U.S. patent application number 12/479620 was filed with the patent office on 2009-10-01 for nitroxide radioprotector formulations and methods of use.
This patent application is currently assigned to Mitos Pharmaceuticals, Inc.. Invention is credited to Peter C. Hoyle, Kameron W. Maxwell.
Application Number | 20090247580 12/479620 |
Document ID | / |
Family ID | 32073352 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090247580 |
Kind Code |
A1 |
Maxwell; Kameron W. ; et
al. |
October 1, 2009 |
NITROXIDE RADIOPROTECTOR FORMULATIONS AND METHODS OF USE
Abstract
Pharmaceutical compositions useful in preventing and treating
negative side effects accompanying radiotherapy are disclosed. More
particularly, new formulations that can be applied to the skin and
mucous membranes of patients undergoing radiotherapy and methods of
using these formulations are disclosed.
Inventors: |
Maxwell; Kameron W.; (Rancho
Santa Fe, CA) ; Hoyle; Peter C.; (Lovettsville,
VA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET, FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Assignee: |
Mitos Pharmaceuticals, Inc.
Newport Beach
CA
|
Family ID: |
32073352 |
Appl. No.: |
12/479620 |
Filed: |
June 5, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10675225 |
Sep 29, 2003 |
|
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12479620 |
|
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|
|
60429887 |
Nov 26, 2002 |
|
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60415089 |
Oct 1, 2002 |
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Current U.S.
Class: |
514/315 |
Current CPC
Class: |
A61K 9/0014 20130101;
A61P 1/00 20180101; A61P 39/00 20180101; A61K 47/10 20130101; A61P
17/00 20180101; A61K 9/12 20130101; A61K 47/38 20130101; A61P 17/14
20180101; A61K 31/445 20130101 |
Class at
Publication: |
514/315 |
International
Class: |
A61K 31/445 20060101
A61K031/445; A61P 1/00 20060101 A61P001/00 |
Claims
1. A composition comprising a solvent suitable for topical
administration to a mucous membrane; and an effective amount of a
nitroxide sufficient for treating or preventing mucositis or
proctitis; wherein the composition is a liquid composition suitable
for topical administration to a mucous membrane; whereby upon the
application of radiation, the administered composition does not
leave an amount of residue sufficient to enhance burning of the
mucous membrane.
2. The composition of claim 1, wherein the composition does not
comprise significant amounts of alcohol.
3. The composition of claim 1, wherein the solvent does not
comprise alcohol.
4. The composition of claim 1, wherein the mucous membrane is the
oral mucosa.
5. The composition of claim 4, wherein the effective amount of the
nitroxide is sufficient for treating or preventing mucositis.
6. The composition of claim 5, wherein the mucositis is oral
mucositis.
7. The composition of claim 1, wherein the liquid composition is a
spray.
8. The composition of claim 1, wherein the nitroxide is
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl.
9. The composition of claim 1, wherein the nitroxide is
2,2,6,6-tetramethylpiperidine-1-oxyl.
10. The composition of claim 1, wherein an effective amount of the
nitroxide is about 70 mg/mL.
11. A composition comprising a solvent suitable for topical
administration to the oral mucosa of a human subject; an effective
amount of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl sufficient
for treating or preventing oral mucositis; wherein the composition
is a liquid composition suitable for topical administration to the
mouth; wherein the composition does not contain a significant
amount of alcohol; whereby upon the application of radiation, the
administered composition does not leave an amount of residue
sufficient to enhance burning of the mucous membrane.
12. A method of treating or preventing mucositis or proctitis in a
subject, comprising: administering the composition of claim 1 to a
mucous membrane of a human subject, wherein said administering
prevents or treats mucositis or proctitis.
13. The method of claim 12, wherein the nitroxide is
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl.
14. The method of claim 12, wherein the human subject is a cancer
patient.
15. The method of claim 12, further comprising administering
chemotherapy to the patient.
Description
RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 10/675,225, filed Sep. 29, 2003, which claims
priority to U.S. Provisional Application No. 60/415,089, filed Oct.
1, 2002, and U.S. Provisional Application No. 60/429,887, filed
Nov. 26, 2002, both of which are expressly incorporated by
reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
preventing or treating the negative side effects which accompany
radiotherapy. More particularly, this invention relates to the
discovery of new formulations that can be applied to the skin and
mucous membranes of patients undergoing radiotherapy and methods of
using these formulations.
BACKGROUND OF THE INVENTION
[0003] Radiation therapy is an important tool in the fight against
cancer and is used in the treatment of as many as 50% of all cancer
patients. Accordingly, more than half a million cancer patients
receive radiation therapy each year. While the use of radiation
therapy is an effective way to treat many kinds of cancer, there
are many complications that may result. Common complications can
include negative effects on the patients skin, hair follicles, and
mucous membranes.
[0004] Common skin complications of radiotherapy include erythema
and folliculitis. These disorders can be very irritating to
patients as they both involve pruritus and redness of the skin.
These and other skin complications can arise through oxidative and
other stress caused by radiation. Other examples of skin conditions
caused by radiation include fibrosis, dry desquamation and moist
desquamation.
[0005] In addition, hair follicles are quite sensitive to
radiotherapy. Accordingly, if hair is in the radiation treatment
beam field, it can cease to grow and fall out. Losing one's hair
can be a source of embarrassment and loss of self esteem.
[0006] Radiotherapy can also have negative effects on the mucous
membranes in the eyes, nose, mouth, vagina, rectal mucosa and the
like. For example, oral mucositis, also called stomatitis, results
from the local effects of radiation to the oral mucosa. Mucositis
is characterized by inflammation of the mucosa of the mouth and
ranges from redness to severe ulceration. Symptoms of mucositis
vary from pain and discomfort, to an inability to tolerate food or
fluids. Even worse, oral mucositis may be so severe as to limit the
patient's ability to tolerate further radiotherapy or
chemotherapy.
[0007] Patients with damaged oral mucosa and a reduced immunity
resulting from radiotherapy are also prone to opportunistic
infections in the mouth. Accordingly, mucositis may also further
compromise a patient's response to treatment and/or palliative
care. It is therefore extremely important that mucositis be
prevented whenever possible, or at least treated to reduce its
severity and possible complications.
[0008] Another common mucous membrane condition caused by
radiotherapy is proctitis. Proctitis is an inflammation of the
lining of the rectum (rectal mucosa). The most common symptom is a
frequent, or continuous sensation, or urge to have a bowel
movement. Other symptoms include constipation, a feeling of rectal
fullness, left-sided abdominal pain, passage of mucus through the
rectum, rectal bleeding, and anorectal pain.
[0009] Some have previously suggested the use of Tempol, a stable
nitroxide radical characterized by the chemical formula
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, as a topical
formulation to ameliorate the effects of radiotherapy. (See e.g.
Proctor, U.S. Pat. No. 5,352,442, and Mitchell, U.S. Pat. No.
5,462,946, both of which are hereby incorporated by reference in
their entireties). These references limit the topical use of Tempol
to formulations selected from creams, lotions, shampoos, cream
rinses, and ointments. It is now recognized that these kinds of
topical formulations are unsuitable for administration shortly
before the actual delivery of radiotherapy to the patient. Indeed,
these product forms leave residues that can result in topical
burning, including severe burns, when radiation is administered.
Accordingly, there is a need in the art to provide a topical
formulation that can be administered to a patient shortly before
the actual delivery of radiotherapy.
SUMMARY OF THE INVENTION
[0010] Embodiments of the invention relate to pharmaceutical
compositions for use in ameliorating an effect of radiotherapy on
skin, mucous membranes, or hair follicles including a solvent and
an effective prophylactic or therapeutic amount of a nitroxide
radioprotector in solution in the solvent, preferably a solvent
that is thickened or is in the form of a low-residue gel. Certain
preferred embodiments the nitroxide radioprotector are TEMPO,
2,2,6,6-tetramethylpiperidine-1-oxyl, and TEMPOL,
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl.
[0011] Pharmaceutical compositions can include solvents selected
from the group consisting of water, urea, alcohols, and glycols. In
embodiments where the solvent is an alcohol, the alcohol may
advantageously be selected from the group consisting of methanol,
ethanol, propanol, butanol, and the like. In embodiments where the
solvent is a glycol, the glycol may advantageously be selected from
the group consisting of ethylene glycol, propylene glycol, and the
like. In certain embodiments, it is preferred to use water, or
other non-irritating liquids, as a solvent for formulations to be
administered to the mucous membranes. In additional embodiments,
solvents used for mucous membrane formulations are not irritating
(e.g., alcohol, urea, and the like).
[0012] In particular embodiments, pharmaceutical compounds
described herein can ameliorate conditions caused or enhanced by
radiotherapy including skin conditions, mucous membrane conditions,
hair follicle conditions, and the like. In specific embodiments the
particular skin conditions that the pharmaceutical compositions can
treat or prevent include erythema, folliculitis, fibrosis, dry
desquamation, moist desquamation, hyperpigmentation, dermatitis,
and the like. In some embodiments, pharmaceutical compositions
described herein can prevent mucous membrane conditions such as
oral mucositis, proctitis, and the like, and are particularly
valuable in protecting the rectal mucosa during radiotherapy of
tumors in that area, such as prostate tumors. Additionally, in
other embodiments the pharmaceutical compositions can treat or
prevent hair follicle conditions such as alopecia, and the
like.
[0013] In further embodiments, the effective prophylactic or
therapeutic amount of the nitroxide radioprotector is an amount
from about 0.01 to about 100 mg/ml of the formulation. Specific
examples of particular amounts contemplated include about 0.02,
0.03, 0.04, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45,
0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1, 2,
3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54,
55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71,
72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88,
89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100 or more mg/ml. In
certain embodiments, the nitroxide radioprotector is
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl.
[0014] Additional embodiments include pharmaceutical compositions
including a polymer selected from the group consisting from
ethylene polymers, acrylic polymers, polyvinylpyrrolidones (PVPs),
polyvinyl copolymers, cellulose polymers, natural polymers,
polystyrene polymers, silicone polymers, and inorganic
polymers.
[0015] Further embodiments include pharmaceutical compositions
having a viscosity such that the nitroxide radioprotector will
remain in contact with a treated area for a sufficient period of
time to allow absorption of a pharmacologically effective amount
into said treated area.
[0016] Embodiments of the invention also include pharmaceutical
compositions for use in ameliorating an effect of radiotherapy to
skin, mucous membranes, or hair follicles including a solvent and
an effective prophylactic or therapeutic amount of a nitroxide
radioprotector in solution in the solvent, preferably wherein the
pharmaceutical composition is thickened with a viscosity-enhancing
agent, such as carboxymethylcellulose, a gum such as guar gum, an
alginate, or other low-residue thickening agent, or is in the form
of a low-residue gel. The thickening or gelling agent should be
selected so as not to leave a sufficient residue to enhance burning
to the skin or mucous membranes when radiotherapy is applied. In
certain embodiments, the nitroxide radioprotector is
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl.
[0017] Additional embodiments include pharmaceutical compositions
for use in preventing or treating alopecia including a solvent and
an effective prophylactic or therapeutic amount of
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl in solution in the
solvent, wherein the pharmaceutical composition is in the form of a
low-residue gel.
[0018] Other embodiments include methods of treating a patient
comprising topically applying a sufficient amount of nitroxide
radioprotector to prevent or treat harmful side effects caused by
radiotherapy, wherein the nitroxide radioprotector is in solution
in a solvent. In preferred embodiments the nitroxide radioprotector
is 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl. Other
advantageous embodiments include solutions in the form of a
low-residue gel or thickened liquid. In certain embodiments, the
solvent can be selected from the group consisting of water, urea,
alcohols, and glycols. It is preferred that harmful side effects
are selected from the group consisting of skin conditions such as
erythema, folliculitis, fibrosis, dry desquamation, moist
desquamation, hyperpigmentation, and dermatitis, mucous membrane
conditions such as oral mucositis and proctitis, hair follicle
conditions such as alopecia, cytotoxicity and polynucleic acid
damage.
[0019] Additional embodiments include methods of treating a patient
including topically applying a sufficient amount of nitroxide
radioprotector to prevent or treat a harmful side effect caused by
radiotherapy, wherein the nitroxide radioprotector is in solution
in solvent, evaporating solvent, and applying radiotherapy to the
patient. In certain embodiments, the nitroxide radioprotector is
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl.
[0020] Further embodiments include methods of treating a patient,
including topically applying a sufficient amount of nitroxide
radioprotector to prevent or treat harmful side effects caused by
radiotherapy, wherein the nitroxide radioprotector is in solution
and is in the form of a low-residue gel or thickened liquid. In
certain embodiments the nitroxide radioprotector is
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a bar graph providing the measured concentration
of normal Tempol in receptor fluid after in vitro percutaneous
absorption of four different topical Tempol formulations
(Formulations I-IV) into human skin for 15 minutes.
[0022] FIG. 2 is a bar graph providing the measured concentration
of oxidized Tempol oxidized receptor fluid after in vitro
percutaneous absorption of four different topical Tempol
formulations (Formulations I-IV) into human skin for 15
minutes.
[0023] FIG. 3 is a bar graph providing the measured concentration
of normal Tempol in wipe samples after in vitro percutaneous
absorption of four different topical Tempol formulations
(Formulations I-IV) into human skin for 15 minutes.
[0024] FIG. 4 is a bar graph providing the measured concentration
of oxidized Tempol in wipe samples after in vitro percutaneous
absorption of four different topical Tempol formulations
(Formulations I-IV) into human skin for 15 minutes.
[0025] FIG. 5 is a line graph comparing the measured concentration
of normal and oxidized Tempol in tape strips after in vitro
percutaneous absorption of Formulation I into human skin for 15
minutes.
[0026] FIG. 6 is a line graph comparing the measured concentration
of normal and oxidized Tempol in tape strips after in vitro
percutaneous absorption of Formulation II into human skin for 15
minutes.
[0027] FIG. 7 is a line graph comparing the measured concentration
of normal and oxidized Tempol in tape strips after in vitro
percutaneous absorption of Formulation III into human skin for 15
minutes.
[0028] FIG. 8 is a line graph comparing the measured concentration
of normal and oxidized Tempol in tape strips after in vitro
percutaneous absorption of Formulation IV into human skin for 15
minutes.
[0029] FIG. 9 is a bar graph providing the measured concentration
of normal Tempol in tape strips after in vitro percutaneous
absorption of four different topical Tempol formulations
(Formulations I-IV) into human skin for 15 minutes.
[0030] FIG. 10 is a bar graph providing the measured concentration
of oxidized Tempol in tape strips after in vitro percutaneous
absorption of four different topical Tempol formulations
(Formulations I-IV) into human skin for 15 minutes.
[0031] FIG. 11 is a bar graph providing the measured concentration
of normal Tempol on viable epidermis and dermis after in vitro
percutaneous absorption of four different topical Tempol
formulations (Formulations I-IV) into human skin for 15
minutes.
[0032] FIG. 12 is a bar graph providing the measured concentration
of oxidized Tempol on viable epidermis and dermis after in vitro
percutaneous absorption of four different topical Tempol
formulations (Formulations I-IV) into human skin for 15
minutes.
[0033] FIG. 13 is a bar graph providing the measured concentration
of normal Tempol in receptor fluid after in vitro percutaneous
absorption of a moderately gelled 7% Tempol ethanol/water topical
formulation into human skin for 15 minutes.
[0034] FIG. 14 is a bar graph providing the measured concentration
of oxidized Tempol in receptor fluid after in vitro percutaneous
absorption of a moderately gelled 7% Tempol ethanol/water topical
formulation into human skin for 15 minutes.
DETAILED DESCRIPTION
Radiotherapy and Cancer
[0035] Radiation therapy works by directing ionizing radiation into
the area being treated with the goal of damaging the genetic
material of cancerous cells thereby making it impossible for these
cells to divide. Accordingly, radiotherapy is an important tool in
the fight against cancer and is used in the treatment of as many as
50% of all cancer patients. In fact, more than half a million
cancer patients receive radiation therapy each year, either alone
or in conjunction with surgery, chemotherapy or other forms of
cancer therapy. Other terms for radiotherapy include radiation
therapy, x-ray therapy, electron beam therapy, cobalt therapy, or
irradiation.
[0036] Radiotherapy is especially useful in cases where surgical
removal of the cancer is not possible, where surgery might
debilitate the patient, or where surgical debulking of the tumor
has not absolutely removed all cancerous tissue. Radiotherapy is
routinely used following surgery to destroy any cancer cells that
were not removed by surgery. Further uses of radiotherapy are prior
to surgery where it can "shrink" a previously inoperable tumor down
to a manageable size to enable surgical excision.
[0037] Radiation therapy can also be used to help relieve symptoms
of advanced cancer (such as bleeding or pain), even if a cure is
not possible. Over one-third of the practice of radiation therapy
is palliative. The typical intent of palliative treatment is to
relieve pain quickly and maintain symptom control for the duration
of the patient's life. Accordingly, treatment is usually tailored
to the patient's clinical condition and overall prognosis.
Palliative treatment is often complementary to analgesic drug
therapies and may enhance their effectiveness because it can
directly target the cause of pain.
[0038] Specifically, radiotherapy can be used to treat localized
solid tumors, such as cancers of the skin, head and neck, brain,
breast, prostate, cervix, and the like. Radiation therapy can also
be used to treat cancers of the blood-forming cells and lymphatic
system including leukemia and lymphoma respectively, and the like.
Mucous membranes or hair in the vicinity of the radiation or in the
path of the radiation (e.g., scalp hair in the case of a brain
tumor and rectal mucosa in the case of prostate cancer) can be
protected using the present invention.
Radiation Forms and Dosage
[0039] External beam radiation therapy commonly uses photons, which
are sometimes called "packets of energy," to treat cancer. It is an
object herein to ameliorate the negative effects of all
radiotherapy regardless of the form of the photon or particle,
including x-rays, gamma rays, UV rays including UV-A, UV-B and
UV-C, neutrons, protons, and electrons including beta particles and
the like.
[0040] X-rays are a very common form of radiation used in
radiotherapy. Gamma rays are another form of photons used in
radiotherapy. Gamma rays can be produced spontaneously as certain
elements (such as radium, uranium, and cobalt 60), which release
radiation as they decompose, or decay. Each element decays at a
specific rate and can give off energy in the form of gamma rays and
other particles. Typically x-rays and gamma rays have the same
general effect on cancer cells.
[0041] External beam radiation therapy can be delivered by means of
a linear accelerator. Typically, linear accelerators use powerful
generators to create the high energy rays for external beam
radiation therapy. Generally, linear accelerators are capable of
producing x-rays at various energies. The linear accelerator can
include a special set of lead shutters, called collimators, which
focus and direct the rays to the tumor. The linear accelerator can
be a large "L-shaped" design which allows it to rotate and deliver
radiation from all angles. Multiple angles allow the maximum amount
of radiation to be delivered to the tumor while delivering a
minimal amount of radiation to the surrounding healthy tissue. The
formulations and methods described herein can be used in
conjunction with collimators or other devices and methods that
limit radiation exposure to normal cells.
[0042] Formulations and methods described herein are capable of
ameliorating the effects of most forms of radiotherapy. For
example, the compositions and methods can ameliorate the effects of
local-field radiation and wide-field radiation. Local field
radiation relates to a narrow beam of radiation directed at the
specific metastatic site or sites. Customarily, local field
radiation has tended to be used for patients with a long life
expectancy and fewer metastatic sites. In contrast, wide-field
radiation employs a larger field of radiation and is often used to
treat patients with a shorter life expectancy and multiple
metastatic pain-causing sites.
[0043] Radiotherapy dosage is measured by the scientific unit rad
(radiation absorbed dose) which is a radiation energy dose equal to
an energy of 100 ergs per gram of irradiated material. A patient
who receives radiation therapy as a treatment for cancer can
receive several thousand rads over a very short period of time
(weeks or months). In contrast, a typical scanning x-ray contains
far fewer rads. For example, modern mammography systems used to
take x-ray images of the breast use approximately 0.1 to 0.2 rad
dose per x-ray.
[0044] According to traditional radiotherapy, the larger the daily
dose of radiation, the lower the total dose that can be
administered because of limits to normal tissue tolerance.
Proportionately more tumor cells are killed when the daily
radiation dose is larger. Typically a balance is obtained between
the killing of tumor cells and the adverse radiation effects on
normal tissues, which are largely a function of the daily dose. A
number of different schedules have been developed that take into
account specific tumor characteristics and the tolerance of normal
tissues. The literature is divided regarding the optimal radiation
schedule to achieve tumor regression and disease palliation of
either primary or metastatic sites. Generally, however, radiation
treatment is planned in relation to clinical status. Because a main
objective herein is to ameliorate the negative effects of radiation
therapy, normal tissue can have a higher tolerance to radiation
therapy and larger dosages of radiation can be administered
safely.
Side Effects of Radiation
[0045] In general, radiation therapy is a local treatment. It
typically affects the cells in the treated area. However, as
mentioned above, in addition to damaging cancer cells, radiation
can also damage normal cells located in the treated area. Normal
cells that are located in the treated area can include skin cells,
mucous membranes, hair follicles, and the like.
[0046] Radiation side effects are typically restricted to the
radiation portal and can be classified as either acute, occurring
during or immediately after the course of radiation therapy, or
late, occurring months to years later. Acute radiation effects are
more prominent with radiation schedules that deliver high total
doses of radiation with small daily fractions; they generally begin
at the end of the second week of therapy. Acute radiation effects,
occurring primarily at skin and mucosal surfaces, usually consist
of an inflammatory response such as skin erythema or pigmentation,
or as mucositis. Late radiation effects may arise without any
preceding acute reactions. Fibrosis is the most common type of late
radiation injury and can be observed in many types of tissue,
including skin.
[0047] Other skin conditions caused by radiation therapy include
dry and moist desquamation. Dry desquamation, which is
characterized by dry and flaky skin and pruritus in the area of
irradiation. Moist desquamation, is characterized by sloughing of
the epidermis, exposing the moist, raw, dermis layer of the
skin.
[0048] The rate at which particular hair cells grow is directly
proportional to their sensitivity to radiotherapy. Accordingly, the
following lists represents particular hair cells' sensitivity to
radiotherapy in decreasing order: scalp hair, male beard, eyebrows
axilla, pubis, and lastly fine hair. The hair follicle's epithelium
is derived from the epidermis and is similarly radiosensitive. As a
result, the follicular cells may develop an acute dermatitis, or
hyperpigmentation earlier than other cells in the dermis. Hair
follicles' sensitivity to radiation can often lead to alopecia in a
patient undergoing radiotherapy.
[0049] One objective described herein is to ameliorate the negative
effects of radiation therapy on normal cells, regardless of whether
the effect is acute or late, or whether the effect relates to the
patient's skin, mucous membranes, hair follicles, or other treated
areas.
Nitroxide Radioprotectors
[0050] The term nitroxide radioprotectors, as used herein, includes
any nitroxide capable of ameliorating an effect of radiotherapy.
Typically nitroxides relate to stable free radical compounds that
can react with a variety of biologically relevant compounds,
including other free radicals, such as OH and H. Generally
nitroxide radioprotectors can ameliorate most of the effects of
radiotherapy including, but not limited to, protecting against
cytotoxicity and polynucleic acid (e.g., DNA, RNA) damage,
including mutagenicity. Further examples of effects that nitroxide
radioprotectors can ameliorate include, but are not limited to skin
conditions, mucous membrane conditions, and hair follicle
conditions. In certain embodiments nitroxide radioprotectors
include nitroxides that can react with oxy radicals, such as
antioxidants, for example. In additional embodiments, nitroxide
radioprotectors can neutralize superoxides and hydrogen
peroxide.
[0051] According to certain embodiments the nitroxide
radioprotector can be selected from the following formulas:
##STR00001##
[0052] Wherein X is selected from O. and OH, and R is selected from
COOH, CONH, CN, and CH.sub.2NH.sub.2
##STR00002##
[0053] Wherein X is selected from O. and OH, and R.sub.1 is
selected from CH.sub.3 and spirocylohexyl, and R.sub.2 is selected
from C.sub.2H.sub.5 and spirocyclohexyl
##STR00003##
[0054] Wherein X is selected from O. and OH and R is selected from
CONH.
##STR00004##
[0055] Wherein X is selected from O. and OH and R is selected from
H, OH, and NH.sub.2 and T is selected from O.
[0056] Suitable Nitroxide radioprotectors can also be found in
Proctor, U.S. Pat. No. 5,352,442, and Mitchell et al., U.S. Pat.
No. 5,462,946, both of which are hereby incorporated by reference
in their entireties.
[0057] A non-limiting list of nitroxide radioprotectors include,
2-ethyl-2,5,5-trimethyl-3-oxazolidine-1-oxyl (OXANO),
2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO),
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL),
4-amino-2,2,6,6-tetramethyl-1-piperidinyloxy (Tempamine),
3-Aminomethyl-PROXYL, 3-Cyano-PROXYL, 3-Carbamoyl-PROXYL,
3-Carboxy-PROXYL, and 4-Oxo-TEMPO. These materials can be used as
the sole active ingredient, or can be used with
hair-growth-promoters such as Nicorandil and Minoxidil.
[0058] As used herein, nitroxide radioprotectors are solutes
dissolved in a suitable solvent. This is to be distinguished from
dispersions, suspensions, or emulsions of nitroxide
radioprotectors, as were used in the prior art.
[0059] Although at least one nitroxide radioprotector is an active
ingredient in all compositions described herein, these compositions
can also include other active ingredients that are capable of
ameliorating the negative effects of radiotherapy or chemotherapy.
Accordingly, nitroxide radioprotectors can be used alone or in
combination with other nitroxide radioprotectors, hair growth
stimulants or additaments. Other hair growth stimulants and
additaments include hydroxyl radical scavengers, antiandrogens and
other compounds described in International Publication No. WO
87/00427 and European Patent application No. 89300785.6, both of
which are hereby incorporated by reference in their entirety. In
certain embodiments, nitroxide radioprotectors can be used along
with other anti-oxidative agents such as glutathione and the
like.
[0060] Nitroxide radioprotectors can ameliorate numerous negative
effects of radiotherapy including conditions to the skin, mucous
membranes, hair follicles, and the like. Skin conditions that
nitroxide radioprotectors can help prevent or treat include
erythema, folliculitis, fibrosis, dry desquamation moist
desquamation, hyperpigmentation and dermatitis and the like. Mucous
membrane conditions that nitroxide radioprotectors can help prevent
or treat include oral mucositis, proctitis, and the like. Nitroxide
radioprotectors can also help prevent or treat alopecia and the
like by stimulating hair growth. Stimulating hair growth can
include increasing rate of growth, increasing hair diameter,
follicular neogenesis, and the like. Nitroxide radioprotectors can
also inhibit hair loss or alopecia from progressing.
[0061] Further embodiments herein include methods of preventing or
treating hair loss or alopecia regardless of whether the condition
was brought about by radiation therapy or other means. For example,
it is well known that hair loss or alopecia can result from genetic
factors, aging, local skin conditions, systemic diseases, and
chemotherapy, for example. Those with skill in the art will
recognize that the embodiments described herein encompass
compositions and methods relating to formulations that are
effective at treating or preventing any type of hair loss without
leaving an unwanted residue on the treated area. Further
embodiments include compositions and methods relating to
formulations that are effective at treating or preventing any type
of hair loss and have a sufficient viscosity such that the
formulation does not immediately run off the treated area upon
application to a patient.
[0062] Developing low-residue formulations can be done by preparing
solutions of nitroxide radioprotectors in low-residue gels,
thickened liquids, liquids and the like. Developing low-residue
formulations with sufficient viscosity can be done by preparing
solutions of nitroxide radioprotectors in low-residue gels or
thickened liquids.
[0063] In certain embodiments, the nitroxide radioprotector is
present in a topical solution at between approximately 5-15% by
weight. In other embodiments, the nitroxide radioprotector is
present in a topical solution at between approximately 7-12% by
weight. In more specific embodiments, the nitroxide radioprotector
makes up 7% by weight of the topical solution. Preferably the
nitroxide radioprotector is dissolved in an ethanol based
solution.
[0064] A gel according to the present invention will typically
comprise a major amount of a liquid phase and a minor amount of a
thickening or gelling agent. The gelling agent, in preferred
embodiments, will comprise only 5%, 4%, 3%, 2%, 1%, 0.5% or less of
the total volume or weight of the composition; thus, when applied
to the skin or mucosa, the liquid can evaporate, leaving only the
gelling agent and the active ingredient. In this manner, 98%, 99%,
or more of the carrier for the drug can disappear prior to
radiotherapy, greatly reducing or eliminating topical burning due
to the bolus effect.
[0065] It should be noted that in a preferred embodiment of the
invention, the liquid phase of a rectal gel (or other gel for
mucosal use) is specifically selected for non-irritating mucosal
properties. Thus, an aqueous vehicle is appropriate, as well as
non-irritating alcohols (such as glycols or polyols) and other
non-irritating solvents. It may be desirable, in practicing the
present invention, to rectally administer an effective,
radioprotective quantity of a nitroxide gel, and then preferably to
retain the gel in the rectum during radiotherapy, or less
preferably to remove the gel prior to radiotherapy.
Tempol
[0066] As mentioned above, one preferred nitroxide radioprotector
that can be used in the pharmaceutical formulations described
herein is Tempol. Tempol is a stable nitroxide radical which is
readily available from commercial suppliers. Tempol is
characterized by the chemical formula
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl.
[0067] Tempol can ameliorate numerous negative effects of
radiotherapy including conditions to the skin, mucous membranes,
hair follicles, and the like. Skin conditions that Tempol can help
prevent or treat include erythema, folliculitis, fibrosis, dry
desquamation moist desquamation, hyperpigmentation, dermatitis, and
the like. Mucous membrane conditions that Tempol can help prevent
or treat include oral mucositis, proctitis, and the like. Hair
follicle conditions that Tempol can help prevent or treat include
alopecia and the like by stimulating hair growth. Stimulating hair
growth relates to increasing rate of growth, increasing hair
diameter, follicular neogenesis and the like. Tempol is also
capable of inhibiting hair loss or alopecia from progressing.
[0068] As mentioned in the Background, the prior art has limited
the topical use of Tempol to the formulations selected from creams,
lotions, shampoos, cream rinses, and ointments. This invention
focuses on the discovery that prior art topical forms of Tempol
should not be administered shortly before the actual delivery of
radiotherapy to the patient. These prior art topical formulations
leave a residue or film on the patient's treated area (e.g., skin,
mucous membranes). If this residue or film is left on the treated
area before radiotherapy, it can intensify or absorb the radiation
and can cause potentially severe burning. This burning caused by
the residue or film can be described as a bolus effect. (See
generally, Hilderley, Oncology Nursing Forum, vol. 10 No. 1, pp.
51-56 (1983)) Accordingly, compositions and methods herein include
topical formulations that can be administered to a patient shortly
before the actual delivery of radiotherapy. This can be done by
topically applying Tempol in the form of a low-residue formulation,
including, but not limited to solutions of Tempol in low-residue
gels, thickened liquids, liquids and the like.
Suitable Solvents
[0069] Nitroxide radioprotectors, such as Tempol, are readably
soluble in aqueous solutions. In some embodiments nitroxide
radioprotectors can be dissolved in a solvent and prepared into a
formulation including low-residue gels, low-residue thickened
liquids, and low-residue liquids. Those skilled in the art will
readily appreciate that any water miscible liquid, at appropriate
levels, can be used as a solvent, including, but not limited to,
glycerin, PEG's, polysorbates, etc. Because a main objective of the
formulations and methods provided herein is to prepare low-residue
nitroxide radioprotector formulations, embodiments herein include
solvents that are relatively volatile. The term "relatively
volatile" relates to solvents that are readily vaporizable at
relatively low temperatures. For example, embodiments herein
include solvents that are readily vaporizable between about
0-38.degree. C. Such liquids, for example, may advantageously have
a vapor pressure of at least 50 mmHg at 25.degree. C., and more
preferably a vapor pressure of at least 75, 90, 100, 150, 200, 250,
or 300 mmHg. Accordingly, further embodiments include formulations
and methods wherein the solvent has completely or substantially
evaporated prior to the application of radiotherapy to the treated
area.
[0070] The following is a non-exclusive list of solvents that can
be used as a solvent for nitroxide radioprotectors: water, urea,
alcohols and glycols. Any alcohol capable of dissolving nitroxide
radioprotectors can be used in the formulations and methods
described herein; examples include methanol, ethanol, propanol,
butanol and the like. Likewise, any glycol capable of dissolving
nitroxide radioprotectors can be used in the formulations and
methods described herein; examples include ethylene glycol,
propylene glycol and the like. In one preferred embodiment, the
solvent not only dissolves the nitroxide radioprotector, but also
facilitates transdermal delivery. Thus,
transdermal-delivery-facilitating agents, particular those that
disrupt or solubilize components of the stratum corneum, are
particularly preferred. We have found that various alcohols, for
example, facilitate penetration of nitroxide radioprotectors into
the skin. Additional embodiments include available transdermal
enhancers that allow for systemic treatment of a patient.
[0071] In certain embodiments of the invention, the concentration
of the active ingredient, a nitroxide radioprotector, can be at a
concentration level at or near its solubility limit. For example a
nitroxide radioprotector can be about 80%, 81%, 82%, 83%, 84%, 85%,
86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%,
99% and 100% of saturation in the solution. Embodiments also
include formulations where a nitroxide radioprotector is soluble
enough in the solvent to promote its release at the desired rate
upon application to the treated area.
[0072] In certain embodiments, the solvent can comprise between
approximately 70-90% of the solution. In other embodiments, the
solvent comprises between approximately 75-86% of the solution. In
more specific embodiments, the solvent comprises approximately 79%
of the solution.
[0073] All of the above described solvents can be used with both
the low-residue gels, thickened liquids and liquids described
herein.
Characteristics of Nitroxide Radioprotector Formulations
[0074] Embodiments herein include topical formulations containing a
nitroxide radioprotector dissolved in solution. All of the solvents
described above can be used in the formulations described
herein.
[0075] Topical formulations can be prepared such that they can
readily be applied to all areas of a patients skin, including the
scalp, face, neck, chest, arms, legs, torso, back, and the like.
Topical formulations can also be prepared such that they can be
applied to all mucous membranes of a patient including areas of the
eyes, mouth, nose, vagina, rectum, and the like. In certain
embodiments it is preferred that formulations used to treat mucous
membranes include water, or another non-irritating solvents. In
additional embodiments, the formulations to be applied to mucous
membranes lack irritating solvents such as alcohol, urea, and the
like.
[0076] In topical formulations, the total quantity of a nitroxide
radioprotector or other active ingredients absorbed can vary
greatly based on many factors including application area size, the
frequency and vigor of application, and the viscosity or thickness
of the applied vehicle. Other factors influencing drug absorption
are the application site, age and condition of the skin. For
example, non-keratinized, aged, broken or abraded skin will result
in higher drug absorption, because these skin types are more
readily penetrated by an active ingredient. Accordingly, one
embodiment herein is to optimize the absorption of a nitroxide
radioprotector by the treated patient while maintaining a
low-residue formulation.
[0077] Because a primary objective herein is to ameliorate the
negative effects of radiotherapy while not enhancing a bolus
effect, topical composition embodiments should be low-residue. As
used herein, the term "low-residue" refers to formulations that can
be applied to a patient, shortly before undergoing radiotherapy,
without leaving a residue capable of enhancing a bolus effect upon
delivering radiotherapy to the treated area. Any low-residue
formulation can be used according to the methods described herein.
Low-residue formulations include, but are not limited to, gels,
liquids, thickened liquids, and the like. Those with skill in the
art can readily appreciate how to prepare low-residue gels,
low-residue liquids, and low-residue thickened liquids to be used
according to the methods described herein.
[0078] Other embodiments include topical formulations with
sufficient viscosity such that the formulation does not immediately
run off the treated area upon application. In certain embodiments
the pharmaceutical composition should have a viscosity that keeps
the nitroxide radioprotector and other active ingredients in
contact with the treated area for a sufficient period of time to
allow suitable absorption to the treated area. In some embodiments,
gels and thickened liquid formulations can have a suitable
viscosity such that the formulation will not immediately run off
the treated area. Accordingly, methods of retaining the formulation
in place are encompassed herein. As mentioned above, regardless of
the composition's viscosity, there should not be a residue
sufficient to produce a dangerous bolus effect when radiotherapy is
applied to the treated area.
[0079] Alternative embodiments include topical formulations with
low viscosity, including, but not limited to, low-residue liquids
and low-residue thickened liquids. In some embodiments, liquids and
thickened liquids can be applied with the aid of an applicator to
allow suitable application of the nitroxide radioprotector to the
treated area. Applicators can include, but are not limited to,
cloths, rags, sponges, towels, gauze, and like absorbent materials,
and the combination of the applicator and the nitroxide
radioprotector solution is one aspect of the methods described
herein.
[0080] In addition to including a nitroxide radioprotector and a
solvent, the topical compositions herein can also include polymers,
colorants, antimicrobials, preservatives, antioxidants, alcohols,
emollients, additional active ingredients, ingredients that enhance
the permeability of the treated area, water, and other ingredients
commonly used in low-residue topical formulations. Additional
ingredients in the compositions herein are acceptable as long as
the formulation, as a whole, remains low residue.
[0081] Those with skill in the art can readily modify the thickness
of nitroxide radioprotector formulations, whether gels or liquids,
with polymers. Embodiments include formulations including one or
more suitable polymers with moderate to high degree of
compatibility with the solvent used to dissolve the nitroxide
radioprotector. In certain embodiments the polymers can be selected
from ethylene polymers, acrylic polymers, polyvinylpyrrolidones
(PVPs), polyvinyl copolymers, cellulose polymers, including
modified cellulose, natural polymers including collagen,
polystyrene polymers, silicone polymers, inorganic polymers, and
the like.
[0082] Examples of ethylene polymers that can be used include, but
are not limited to, oxidized polyethylene, polyethylene,
polyethylene glycol, and the like.
[0083] Examples of acrylic polymers that can be used include, but
are not limited to, acrylic esters, methacrylic esters copolymer,
acrylic polymer emulsion, carbomer, ethylene acrylates, methacryiol
ethyl betaine, methacrylates copolymer, octylacrylamide, acrylates,
butylaminoethyl methacrylate copolymer, polyacrylamidomethylpropane
sulfonic acid, polyquaternium-5, polyquaternium-6,
polyquaternium-7, polyquaternium-15, and the like.
[0084] Examples of polyvinylpyrrolidones (PVPs) include, but are
not limited to, polyquaternium-11, polyvinylpyrrolidone (PVP),
PVP/dimethylaminoethylmethacrylate copolymers, PVP/Elcosene
copolymer, PVP/ethyl methacrylate/methacrylic acid terpolymer.
PVP/hexadecene copolymer, PVP/VA copolymers, styrene/PVP copolymer,
and the like.
[0085] Examples of polyvinyl copolymers include, but are not
limited to, ethylene vinyl acetate copolymer, PVM/MA copolymer
esters, vinyl acetate/crotonic acid copolymer, vinyl
acetate/crotonic acid/methacryloxybenzophenone-1 copolymer, vinyl
acetate/cotonic acid/vinyl neodecanoate copolymer, carboxymethyl
cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose,
hydroxypropyl methylcellulose, PEG celluloses, polyquaternium-4,
polyquaternium-10, and the like.
[0086] Examples of natural polymers include, but are not limited
to, acacia, agar, alginate, carrageenan, furcelleran, gelatin,
ghatti gum, glycosaminoglycans, guar gum, guar gum derivative,
hydroxypropyl guar, hyaluronic acid, karaya, locust bean gum,
maltodextrin, pectin, tragacanth gum, xanthan, and the like.
[0087] Examples of polystyrene polymers include, but are not
limited to, sodium polystyrene sulfonate.
[0088] Examples of silicone polymers include amino bispropyl
dimethicone, cyclomethicone, dimethicone, dimethicone copolyol,
hexamethyldisiloxane, methicone, octadecyl dimethicone, phenyl
dimethicone, stearoxy dimethicone, and the like.
[0089] Examples of inorganic polymers, include but are not limited
to bentonite, modified bentonite, magnesium aluminum silicate,
modified hectorite, sodium magnesium silicate, and the like.
[0090] The above listed polymers can be used in all compositions
described herein. For example, the polymers can be used in
low-residue gels. The polymers can also be used as thickening
agents in low-residue thickened liquids.
Gels
[0091] As discussed above, in some embodiments, the pharmaceutical
composition is a topical formulation in the form of a low-residue
gel. As used herein, a gel relates to a semisolid system of either
suspensions made up of small inorganic particles or large organic
molecules interpenetrated by a liquid. Generally, if left
undisturbed for some time, gels may be in a semisolid or gelatinous
state. With some gels, small amounts of water may separate on
standing.
[0092] Those with skill in the art will readily know how to prepare
low-residue gels. Detail on how to prepare such gels is provided in
Remington's Pharmaceutical Sciences, 18.sup.th ed. 1990, which is
hereby incorporated by reference in its entirety. In one embodiment
a gel can be prepared by slowly dispersing one or more suitable
polymers in the requisite amount of suitable solvents. A discussion
of suitable solvents and polymers is provided above. According to
one method of preparation, a polymer and a solvent can be stirred
until the polymer is completely dissolved. Water can be added to
the polymer/solvent solution as it is being stirred. A sufficient
amount of a nitroxide radioprotector can be added to the stirred
mixture until the nitroxide radioprotector is adequately
dissolved.
[0093] Gels can be one-phase or multiple phase systems. A gel mass
consisting of a network of small discrete particles is generally
termed a two-phase system while singe-phase gels typically consist
of organic macromolecules distributed uniformly throughout a liquid
in such a manner that no apparent boundaries exist between the
dispersed macromolecules and the liquid.
[0094] In certain embodiments, the low-residue gel can be a
hydroalcoholic gel. In some embodiments an alcohol such as ethanol
can be used to dissolve the nitroxide radioprotector while avoiding
the use of solubilizers such as PEG-40, hydrogenated castor oil,
polysorbate 20 or similar ingredients. The absence of these
solubilizers can greatly improve the cosmetic feel of the product
as the stickiness and rubbery feel can be virtually absent. In
embodiments where the pharmaceutical composition has a significant
alcohol (e.g., ethanol) content, additional preservation may not be
required.
[0095] Those with skill in the art can use numerous methods to
readily prepare hydroalcohol gels with the formulation
characteristics described herein. According to one method of
preparing hydroalcohol gels, a solution can be prepared by
dissolving the nitroxide radioprotector in ethanol. The nitroxide
radioprotector/ethanol solution can be added to a hydrogel.
According to certain embodiments, the nitroxide
radioprotector/ethanol solution can be added to a premade hydrogel
using a slow moving anchor mixer, which can reduce the creation of
air bubbles in the hydroalcohol gel.
[0096] Due to reduced hydrogen bonding, the viscosity of a
hydroalcoholic gel is generally lower than the viscosity of a
corresponding hydrogel. Regardless those with skill in the art can
adjust the ingredients of the hydroalcoholic gel to prepare a
composition with a suitable viscosity tailored to the desired
characteristics. For example the use of the thickening agents or
polymers discussed above can be used to raise the viscosity of a
particular formulation.
[0097] In some embodiments the low-residue gel can be sprayable.
Methods of preparing sprayable gels are well known in the art.
According to one embodiment of preparing a sprayable gel, a
suitable polymer can be added to water. Upon hydration and
development of structure, the thickened polymer/water mixture can
be added to a nitroxide radioprotector/solvent solution.
Liquid Formulations
[0098] Further embodiments herein include nitroxide
radioprotector-containing liquid formulations. For example, a
nitroxide radioprotector can be dissolved in any of the suitable
solvents discussed above. The following is a non-exclusive list of
solvents that can be used as a solvent for Tempol: water, urea,
alcohols, glycols and the like. These liquid formulations can be
used with the aid of an applicator such as a towel, cloth, rag,
sponge, gauze or like absorbent material in order to apply the
formulation to a patient in need.
[0099] Further embodiments include adding polymers to thicken
nitroxide radioprotector containing liquid solutions. Any of the
above described polymers can be used as a thickener for these
formulations. For example, the following polymers can be used as
thickening agents ethylene polymers, acrylic polymers,
polyvinylpyrrolidones (PVPs), polyvinyl copolymers, cellulose
polymers, natural polymers, polystyrene polymers, silicone
polymers, inorganic polymers, and the like.
[0100] Those with skill in the art will readily know how to prepare
thickened liquid solutions according to the methods described
herein. Detail on how to prepare such liquids is provided in
Remington's Pharmaceutical Sciences, 18.sup.th ed. 1990, which is
hereby incorporated by reference in its entirety.
[0101] When the invention is practiced with a thickened liquid, it
is advantageous to thicken the liquid to a viscosity of 20-100,000
or more centipoise. In certain embodiments the formulations
provided herein can have a viscosity between 400-2000 cps, or even
more specific between 900-1500 cps. In more particular embodiments,
the formulations can have a viscosity of approximately 1215
cps.
Methods of Using Compositions
[0102] Method embodiments include using any of the low-residue
formulations described herein on a patient undergoing radiotherapy.
In some embodiments the formulation can be applied shortly before
radiotherapy. Suitable areas for applying the low-residue
formulation include all areas of the skin and mucous membranes.
Methods include, but are not limited to, applying formulations to
the scalp, face, neck, chest, arms, legs, torso, back, and the
like. Further methods include, but are not limited to, applying the
formulations to mucous membranes, including but not limited to,
areas of the mouth, nose, eyes, vagina, rectum and the like.
[0103] Some embodiments include rubbing a low-residue nitroxide
radioprotector containing formulation onto an area of a patient
undergoing radiotherapy. Rubbing can be accomplished using the
practitioner's hands, typically gloved, or may alternatively be
done with an applicator such as a cloth, towel, sponge, rag, gauze
and the like. Other embodiments include spraying the low-residue
formulation onto a treated area of a patient undergoing
radiotherapy. Upon being sprayed on the treated area, the
formulation may be left alone to absorb, or may be rubbed in to
facilitate the absorption of the nitroxide radioprotector.
[0104] Further embodiments include topically applying a sufficient
amount of a nitroxide radioprotector such as
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl to prevent or treat
harmful side effects caused by radiotherapy, wherein the
4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl is in solution and
is in the form of a low-residue gel or thickened liquid.
[0105] In some embodiments, the formulations and methods described
herein can be used to treat or prevent negative side effects of
radiotherapy selected from skin conditions, mucous membrane
conditions, and hair follicle conditions. In some embodiments the
methods herein can be used to treat or prevent skin conditions
including erythema, folliculitis, fibrosis, dry desquamation, moist
desquamation, hyperpigmentation, dermatitis and the like.
Additional embodiments include methods of treating mucous membrane
conditions such as oral mucositis, proctitis, and the like. Further
embodiments include methods of treating hair follicle conditions
such as alopecia.
EXAMPLES
[0106] The following examples teach methods of making and using
nitroxide radioprotector formulations. These examples are
illustrative only and are not intended to limit the scope of the
teachings herein.
Example I
Introduction
[0107] The following study was conducted to evaluate the in vitro
percutaneous absorption of Tempol (4-hydroxy Tempo) from four
vehicles using excised human skin from elective surgery. This study
was conducted using procedures described in the FDA and AAPS Report
of the Workshop on Principles and Practices of In Vitro
Percutaneous Penetration Studies: Relevance to Bioavailability and
Bioequivalence (Pharm. Res. 4:265, 1987), which is hereby
incorporated by reference in its entirety.
Methods
[0108] The Tempol formulations used in this in vitro percutaneous
absorption study were formulated by Dow Pharmaceutical Sciences,
Petaluma, Calif. The composition of these formulations is
summarized in Table 1.
TABLE-US-00001 TABLE 1 Tempol Formulation Composition Reference
Lightly Gelled Moderately Sprayable Ethanol Ethanol/ Gelled
Ethanol/ Ethanol/ Solution Water Water Water Formulation ID: I II
III IV % by wt. % by wt. % by wt. % by wt. 4-Hydroxy 7 7 6.1 7
tempo Ethanol 93 76.5 79.5 33 Water 0 15.5 13.1 56.87 Klucel 0 1
1.3 0 Laponite XLG 0 0 0 3.24 Total: 100 100 100 100.11 pH of
Formulations II, III, and IV were adjusted to 7-7.5 with citric
acid
[0109] As indicated in Table 1, four Tempol containing formulations
were prepared. Formulation I, was a reference ethanol solution,
Formulation II was lightly gelled ethanol/water solution,
Formulation III was a moderately gelled ethanol/water solution, and
Formulation IV was a sprayable ethanol/water gel.
[0110] Franz static diffusion cells FDC-400 (15 mm diameter
orifice, O-ring joint, Crown Bio Scientific, Clinton, N.J.) were
mounted on 9-cell manifolds and maintained at a constant
temperature of 32.degree. C. by use of recirculating water baths.
These cells had an opening with a nominal area of 1.767 cm.sup.2
and a receptor compartment with a volume ranging between 12 to 14
mL. Each diffusion cell was assembled by placing the excised human
abdominal skin from a single donor dermal-side down and then a
Teflon.RTM. O-ring (which rested in the groove of the receptor
side, bottom half, of the diffusion cell). The donor side, top
half, of the diffusion cell was then placed on top of the O-ring
which rested on the skin and was held in place by a pinch clamp.
The joint between the donor and receptor compartments of each cell
was wrapped with PARAFILM.RTM. to prevent evaporation of the
receptor solution.
[0111] Each cell was then filled with receptor solution consisting
of degassed PBS with 0.1% sodium azide and 1.5% Oleth-20. Air
bubbles were dispelled from under the skin. The receptor fluid was
continuously stirred using a Teflon magnetic stir bar and an
inoculating loop cut to .about.5.0 cm from the top of the loop. The
skin was allowed to equilibrate with the receptor solution for 1
hour prior to application of formulation.
[0112] A finite dose (0.1 mL/cm.sup.2) of each formulation was
applied onto the skin using a syringe. Each formulation was applied
in an alternating fashion to 6 diffusion cells at 0.18 mL of
formulation per cell. The diffusion cell sampling port was sealed
with PARAFILM.RTM. to prevent evaporation. Following the 15-minute
exposure period, the entire contents of the receptor fluid was
collected into a scintillation vial. The skin was wiped twice
consecutively with a dry cotton swab, and cell caps were removed.
Residual formulation was removed from the stratum corneum with
multiple cellophane tape-strips until no more material was removed
from the skin. The epidermis was physically separated from the
dermis using tweezers. Each section of skin was placed into
separate vials and labeled. All receptor, wipes, tape-strips,
epidermis, and dermis samples were shipped to an analytical
laboratory for analysis. Tempol content was reported as "Normal"
and "Oxidized".
Results
[0113] Skin penetration of Tempol ranged from 0.003 to 0.01 percent
of applied dose from the four formulations. The viable epidermis
and dermis levels ranged from 0.2 to 2.8 percent of applied dose
for the normal analysis and 1.1 to 6.6 percent of applied dose for
the oxidized analysis. The moderately gelled ethanol/water
formulation, Formulation III, exhibited the highest viable
epidermis/dermis levels, 2.8% of applied dose for normal analysis
and 6.6% applied dose for the oxidized analysis. The sprayable
ethanol/water gel formulation, Formulation IV, obtained a result of
2.1% of applied dose for normal analysis. The reference ethanol
solution, Formulation I, obtained a result of 4.4% of applied dose
for the oxidized analysis. Skin deposition and penetration along
with dose recovery are summarized in Tables 2 and 3. More specific
results are provided in FIGS. 1-12.
TABLE-US-00002 TABLE 2 Percutaneous Absorption of Tempol (Normal
and Oxidized) Values are in % of Applied Dose Receptor Wipes Tape
Strips Viable E/D Dose Formulation Normal (%) Normal (%) Normal (%)
Normal (%) Recovered I mean 0.01 15.02 0.27 1.52 16.82 7.00% tempol
SD 0.005 8.02 0.05 1.05 8.25 % cv 81.00 53.40 18.94 69.22 49.03 II
mean 0.003 25.17 0.29 0.20 25.66 6.98% tempol SD 0.004 10.11 0.10
0.18 10.25 % cv 121.12 40.17 35.92 92.27 39.95 III mean 0.01 35.16
0.28 2.81 38.25 6.09% tempol SD 0.01 6.55 0.15 1.96 6.49 % cv 78.56
18.62 54.91 69.89 16.98 IV mean 0.003 41.54 0.14 2.11 43.80 7.00%
tempol SD 0.004 14.45 0.07 0.82 14.44 % cv 110.22 34.79 48.66 39.11
32.97 Receptor Wipes Tape Strips Viable E/D Dose Formulation
Oxidized (%) Oxidized (%) Oxidized (%) Oxidized (%) Recovered I
mean 0.01 22.96 0.35 4.37 27.69 7.00% tempol SD 0.01 9.74 0.10 2.59
11.72 % cv 91.52 42.43 28.14 59.23 42.33 II mean 0.004 30.75 0.52
1.06 32.34 6.98% tempol SD 0.004 11.42 0.18 1.11 12.05 % cv 111.15
37.13 35.54 104.64 37.27 III mean 0.01 82.24 0.50 6.60 44.50 6.09%
tempol SD 0.01 109.93 0.27 5.61 8.80 % cv 78.70 133.68 55.03 85.04
19.78 IV mean 0.004 45.95 0.26 3.34 49.54 7.00% tempol SD 0.004
14.49 0.12 1.05 14.54 % cv 109.70 31.54 48.20 31.61 29.34
TABLE-US-00003 TABLE 3 Percutaneous Absorption of Tempol (Normal
and Oxidized) Values are in .mu.g Receptor Wipes Tape Strips Viable
E/D Cumm Tempol Dose Formulation Normal (.mu.g) Normal (.mu.g)
Normal (.mu.g) Normal (.mu.g) Amount (.mu.g) Amount (.mu.g)
Recovered I mean 0.58 1511.36 27.30 153.62 1692.86 10094.00 16.82
7.00% tempol SD 0.47 788.38 5.34 106.56 809.35 100.76 8.25 % cv
80.93 52.16 19.55 69.37 47.81 1.00 49.03 II mean 0.32 2618.10 29.95
20.45 2668.82 10397.87 25.66 6.98% tempol SD 0.39 1062.63 10.64
18.89 1077.32 147.06 10.25 % cv 121.02 40.59 35.54 92.37 40.37 1.41
39.95 III mean 0.69 3213.88 25.12 256.44 3496.12 9125.87 38.25
6.09% tempol SD 0.54 622.82 13.58 178.77 623.95 239.04 6.49 % cv
78.16 19.38 54.08 69.71 17.85 2.62 16.98 IV mean 0.39 4889.76 16.68
248.48 5155.32 11763.50 43.80 7.00% tempol SD 0.43 1702.51 8.03
98.89 1702.76 200.73 14.44 % cv 110.15 34.82 48.13 39.80 33.03 1.71
32.97 Receptor Wipes Tape Strips Viable E/D Cumm Tempol Dose
Formulation Oxidized (.mu.g) Oxidized (.mu.g) Oxidized (.mu.g)
Oxidized (.mu.g) Amount (.mu.g) Amount (.mu.g) Recovered I mean
0.73 2312.23 35.43 439.36 2787.75 10094.00 27.69 7.00% tempol SD
0.66 964.49 10.22 257.30 1158.30 100.76 11.72 % cv 91.56 41.71
28.85 58.56 41.55 1.00 42.33 II mean 0.39 3196.10 54.03 110.24
3360.77 10397.87 32.34 6.98% tempol SD 0.44 1191.31 19.00 115.65
1257.47 147.06 12.05 % cv 111.16 37.27 35.17 104.91 37.42 1.41
37.27 III mean 0.78 7359.87 45.10 606.41 8012.16 9125.87 89.34
6.09% tempol SD 0.61 9631.31 24.44 528.16 9637.88 239.04 110.11 %
cv 78.53 130.86 54.20 87.10 120.29 2.62 123.25 IV mean 0.45 5409.74
30.07 392.67 5832.94 11763.50 49.54 7.00% tempol SD 0.50 1722.82
14.33 126.28 1729.43 200.73 14.54 % cv 109.61 31.85 47.68 32.16
29.65 1.71 29.34
Conclusion
[0114] The percentage of the applied dose and amount of Tempol
penetrating the skin into the receptor fluid was very low and
ranged from 0.003% to 0.01% and 0.32 ug/1.77 cm.sup.2 to 0.78
ug/1.77 cm.sup.2 of skin respectively, following a 15 minute
duration of skin exposure. This study shows that the moderately
gelled ethanol/water formulation, Formulation III, achieved higher
skin (epidermis/dermis) levels (2.8% of applied dose for normal
analysis and 6.6% applied dose for the oxidized analysis) of Tempol
but not higher skin penetration compared to the reference ethanol
formulation, Formulation I. Results from this initial study suggest
that Formulation III would achieve comparable or better clinical
efficacy following topical application to the head. In addition,
Formulation III should have better formulation retention to the
skin (low run-off) compared to Formulation I.
Example II
Introduction
[0115] This study evaluated the effect of multiple applications of
a moderately gelled 7% Tempol ethanol/water formulation
(Formulation V) on the in vitro percutaneous absorption of Tempol
using similar test procedures as employed in Example I. These test
procedures were consistent with the FDA and AAPS Report of the
Workshop on Principles and Practices of In Vitro Percutaneous
Penetration Studies: Relevance to Bioavailability and
Bioequivalence (Pharm. Res. 4:265, 1987), which is hereby
incorporated by reference in its entirety.
[0116] Test formulations used in this in vitro percutaneous
absorption study were prepared by Dow Pharmaceutical Sciences,
Petaluma, Calif. Formulation compositions are summarized in Table 4
The viscosity of Formulation V was measured using a Brookfield
RVDV-1+viscometer. A sample weighing 8.4134 grams had a measured
viscosity of 1215 cps at 22.9.degree. C.
TABLE-US-00004 TABLE 4 Tempol Formulation Composition Tempol
Vehicle Formulation Formulation Formulation ID: Formulation
Formulation V VI % by wt. % by wt. Supplier 4-Hydroxy 7 0 Mitos
Tempo Ethanol 79.0 86.0 Spectrum Water 13.0 13.0 McGaw Klucel 1.0
1.0 Hercules Total: 100 100
[0117] Each of the four application regimens were performed on six
cells: (1) a single application of Tempol formulation (Formulation
V) 2) two applications of Tempol formulation (Formulation V), (3)
three applications of Tempol formulation (Formulation V), and (4)
one application of Tempol formulation (Formulation V) followed by
one application of Vehicle formulation (Formulation VI). Each
application of formulation had a 30 minute duration of exposure to
the skin surface.
[0118] The skin was wiped with two dry cotton swabs after each
application. Upon completion of the final application and skin
wiping, the stratum corneum was removed from the skin. All samples
of stratum corneum along with the remaining skin (viable
epidermis/dermis), receptor fluid, and skin surface wipes collected
during the study were analyzed in a laboratory for Tempol content.
Tempol content was reported as "Normal", "Oxidized", and
"Reduced."
Methods
[0119] Franz static diffusion cells (15 mm diameter orifice, O-ring
joint, Crown Bio Scientific, Clinton, N.J.) were mounted on 9-cell
manifolds and maintained at a constant temperature of 32.degree. C.
by use of re-circulating water baths. These cells had an opening
with a nominal area of 1.77 cm.sup.2 and a receptor compartment
with a volume ranging between 12 to 14 mL. Each diffusion cell was
assembled by placing the excised human abdominal skin from a single
donor dermal-side down and then a Teflon.RTM. O-ring (which rested
in the groove of the donor side, top half, of the diffusion cell.
The donor side (top half) of the diffusion cell was then placed on
top of the O-ring resting on the skin and held in place by use of a
pinch clamp. The joint between the donor and receptor compartments
of each cell was wrapped with Parafilm.RTM. to prevent evaporation
of the receptor solution.
[0120] Each cell was then filled with receptor solution consisting
of degassed PBS with 0.1% sodium azide and 1.5% Oleth-20. Air
bubbles were dispelled from under the skin. The receptor fluid was
continuously stirred using a Teflon magnetic stir bar and an
inoculating loop cut to .about.3.0 cm from the top of the loop. The
skin was allowed to equilibrate with the receptor solution for 1
hour prior to the application of formulation.
[0121] A finite dose (0.1 mL/cm.sup.2) of formulation was applied
on to the skin using a displacement pipette. The formulation was
applied in an alternating fashion to 6 diffusion cells at 0.18 mL
of formulation per cell. The diffusion cell sampling port was
sealed with PARAFILM.RTM. to prevent evaporation. Following the
30-minute exposure period, the entire contents of the receptor
fluid were collected into a scintillation vial. If appropriate, the
cell was re-dosed with test formulation after removal of the
previous dose using two cotton swabs wiped across the skin surface.
After exposure to the last application of test formulation, the
skin was wiped twice consecutively with a dry cotton swab. Cell
caps were removed. Residual formulation was removed from the
stratum corneum with multiple cellophane tape-strips until no more
material was removed from the skin. The remaining viable
epidermis/dermis was collected. All receptor, wipes, tape-strips,
and viable epidermis/dermis samples were shipped to an analytical
laboratory for analysis.
Results
[0122] Data was provided from the analytical lab in the form of
normal and oxidized Tempol concentrations. Since reduced Tempol is
not detectable by the analytical method, Tempol in the samples was
oxidized such that all Tempol present was in the oxidized form.
Oxidized Tempol represents the total amount of Tempol recovered.
Reduced Tempol was calculated as the oxidized Tempol minus the
normal Tempol.
[0123] Skin penetration of reduced Tempol ranged from 0 .mu.g/1.77
cm.sup.2 to 0.62 .mu.g/1.77 cm.sup.2 of skin following a 30 minute
duration of skin exposure. The second application of Tempol and
additional 30 minute exposure to the skin surface resulted in a
cumulative range from 2.94 .mu.g/1.77 cm.sup.2 to 3.80 .mu.g/1.77
cm.sup.2 of skin. Application of the vehicle formulation
(Formulation VI) following a dose of Tempol formulation
(Formulation V) did not increase the amount of reduced Tempol
penetrating the skin. The third application of Tempol and
additional 30 minute exposure to the skin surface resulted in a
cumulative amount of 8.8 .mu.g reduced Tempol/1.77 cm.sup.2 of
skin.
[0124] The viable epidermis and dermis levels ranged from 153.7
.mu.g/1.77 cm.sup.2 to 496.5 .mu.g/1.77 cm.sup.2 for the normal
analysis, 248.0 .mu.g/1.77 cm.sup.2 to 595.5 .mu.g/1.77 cm.sup.2
for the oxidized analysis, and 57.3 .mu.g/1.77 cm.sup.2 to 96.9
.mu.g/1.77 cm.sup.2 for the reduced result. The highest viable
epidermis/dermis levels were seen with two applications of Tempol,
184.1 .mu.g reduced Tempol/1.77 cm.sup.2 of skin. Skin penetration
and deposition are summarized in Tables 5(a and b) and 6(a and b).
Other results are provided in FIGS. 13 and 14.
Tables 5a & 5b
Percutaneous Absorption of Tempol in .mu.g
TABLE-US-00005 [0125] TABLE 5a Intact Values are in .mu.g, n = 6
cells Viable Viable Viable Test Normal Oxidized Reduced 1 mea 156.
253. 96.9 Single SD 84.6 113. 44.0 Form. V % 54.2 44.8 45.4 2
mea.sup.1 479. 663. 184. Two applications SD.sup.1 232. 345. 167.
Form. V % 48.5 52.1 91.2 3 mea 425. 595. 170. Three SD 180. 310.
130. Form. V % 42.5 52.2 76.8 4 mea 153. 248. 94.3 Form. V then SD
90.6 141. 58.0 Form. VI % 58.9 57.2 61.5 .sup.1Test 2,
TABLE-US-00006 TABLE 5b Normal Values are in .mu.g, 30 minutes 60
minutes 90 minutes Test Normal (.mu.g) Normal (.mu.g) Normal
(.mu.g) 1 mea 3.97 n/a n/a Single SD 2.25 n/a n/a Form. V % 56.7
n/a n/a 2 mea 1.93 57.7 n/a Two applications SD 1.11 29.4 n/a Form.
V % 57.2 50.8 n/a 3 mea 3.48 53.8 98.7 Three SD 1.65 55.9 56.1
Form. V % 47.4 103.9 56.8 4 mea 2.41 21.5 n/a Form. V then SD 1.88
12.5 n/a Form. VI % 78.1 58.1 n/a
Tables 6a & 6b
Percutaneous Absorption of Tempol in .mu.g
TABLE-US-00007 [0126] TABLE 6a Oxidized Values are in .mu.g, 30
minutes 60 minutes 90 minutes Test Oxidized (.mu.g) Oxidized
(.mu.g) Oxidized (.mu.g) 1 mea 3.55 n/a n/a Single SD 1.95 n/a n/a
Form. V % 54.9 n/a n/a 2 mea 1.96 60.7 n/a Two SD 0.86 30.6 n/a
applications Form. V % 43.6 50.3 n/a 3 mea 3.71 57.6 107.5 Three SD
1.51 61.6 61.9 Form. V % 40.6 106.9 57.5 4 mea 3.03 19.6 n/a Form.
V then SD 1.53 13.8 n/a Form. VI % 50.5 70.4 n/a
TABLE-US-00008 TABLE 6b Reduced Values are in .mu.g, 30 minutes 60
minutes 90 minutes Test Reduced (.mu.g) Reduced (.mu.g) Reduced
(.mu.g) 1 mea -- n/a n/a Single SD 0.42 n/a n/a Form. V % -- n/a
n/a 2 mea 0.03 2.94 n/a Two SD 0.42 1.41 n/a applications Form. V %
1424. 47.9 n/a 3 mea 0.24 3.80 8.80 Three SD 0.25 5.96 6.05 Form. V
% 106.5 156.7 68.7 4 mea 0.62 -- n/a Form. V then SD 0.87 10.0 n/a
Form. VI % 139.1 -- n/a
[0127] Drug deposition and penetration was statistically evaluated
by performing unpaired t-tests (significant differences between
formulations are defined with a value of p<0.05). After 30
minute duration of skin exposure, the four application regimens are
statistically comparable to each other in penetration for the
oxidized and normal Tempol (p<0.05) with the exception the
oxidized Tempol for Test 2 versus Test 3 (p=0.033). The amount of
normal, oxidized, and reduced Tempol in Test 2 was statistically
comparable to Test 3 after the second application of Tempol and
additional 30 minute duration of skin exposure. Test 2 after the
second application of Tempol was significantly higher than Test 4
after the application of vehicle and additional 30 minute duration
of skin exposure for the normal and oxidized analysis. Test 2, 3,
and 4 produced comparable levels of reduced Tempol after the second
dosing and additional time. The third application results from test
3 produced levels that were twice as high as the levels in the
second time point. This is suggestive of Tempol reaching a steady
state of absorption.
[0128] Skin deposition of normal and oxidized Tempol after multiple
applications (test 2 and 3) was significantly higher (p<0.05)
than a single application (test 1 and 4). Reduced Tempol was
statistically comparable between all four application tests. In
test 4, application of the vehicle did provide a washing-in effect,
increasing the levels of normal and oxidized Tempol, but it was not
as great of an effect as multiple applications of the active
formulation.
CONCLUSION
[0129] This study shows that two sequential applications of the
moderately gelled ethanol/water formulation achieved higher
deposition and penetration levels of Tempol than a single
application.
Example 3
Prophylactic Treatment for Brain Tumor
[0130] The moderately gelled 7% Tempol ethanol/water formulation of
Example II (Formulation V) is applied twice to the scalp of a brain
tumor patient prior to radiation treatment, and the solvent is
allowed to evaporate. Each application of the formulation has a
minute duration of exposure to the scalp. Conventional radiation
therapy is then administered to the tumor through the scalp.
Following treatment, the patient does not experience epidermal
burning, and hair loss that would otherwise result within 1-2
weeks.
[0131] Although the teachings herein have been described with
reference to embodiments and examples, it should be understood that
various modifications can be made without departing from the spirit
of the invention. Accordingly, the teachings herein are limited
only by the following claims. All references cited herein are
hereby expressly incorporated by reference in their entireties.
* * * * *