U.S. patent application number 11/878364 was filed with the patent office on 2008-01-17 for colloidal suspension of submicronic particles for carrying active principles and their mode of preparation.
This patent application is currently assigned to Flamel Technologies, Inc.. Invention is credited to Nathan Bryson, Gerard Soula.
Application Number | 20080015332 11/878364 |
Document ID | / |
Family ID | 8855105 |
Filed Date | 2008-01-17 |
United States Patent
Application |
20080015332 |
Kind Code |
A1 |
Bryson; Nathan ; et
al. |
January 17, 2008 |
Colloidal suspension of submicronic particles for carrying active
principles and their mode of preparation
Abstract
The invention concerns a suspension of biocompatible particles
for carrying active principles. Said carrier particles are based on
a double-block hydrophilic neutral polyaminoacid/hydrophobic
neutral polyaminoacid copolymer. Said hydrophilic neutral
polyaminoacid/hydrophobic neutral polyaminoacid particles are
capable of combining in colloidal suspension in non-dissolved
state, at least an active principle and of releasing same, in
particular in vivo, in prolonged and/or delayed delivery. The
invention also concerns a powdery solid from which are derived the
carrier particles and the preparation of said solid and of said
suspension of active principle based on hydrophilic neutral
polyaminoacids/hydrophobic neutral polyaminoacids. Said carrier
particles form spontaneously and in the absence of surfactants or
organic solvents, stable aqueous suspensions. The invention also
concerns the carrier particles in dry form, the method for
preparing them, and pharmaceutical compositions (in dry form or
suspension) comprising said carrier particles associated with an
active principle.
Inventors: |
Bryson; Nathan; (Millery,
FR) ; Soula; Gerard; (Meyzieu, FR) |
Correspondence
Address: |
PATTON BOGGS LLP
8484 WESTPARK DRIVE
SUITE 900
MCLEAN
VA
22102
US
|
Assignee: |
Flamel Technologies, Inc.
Parc Club du Moulin a'vent 33, Avenue du Dr. georges
Levy
Venissieux Cedex
FR
|
Family ID: |
8855105 |
Appl. No.: |
11/878364 |
Filed: |
July 24, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10398134 |
Apr 1, 2003 |
7270832 |
|
|
PCT/FR01/03083 |
Oct 5, 2001 |
|
|
|
11878364 |
Jul 24, 2007 |
|
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Current U.S.
Class: |
528/335 |
Current CPC
Class: |
B01J 13/0021 20130101;
A61K 2800/413 20130101; A61Q 19/00 20130101; A61K 9/5138 20130101;
A61K 9/5146 20130101; A61K 8/11 20130101 |
Class at
Publication: |
528/335 |
International
Class: |
C08G 69/08 20060101
C08G069/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 10, 2000 |
FR |
FR00/12837 |
Claims
1-20. (canceled)
21. A method of preparing a copolymer that is a particle precursor,
comprising: a) copolymerizing monomers of amino acid N-carboxy
anhydrides (NCA) of at least types (i) and (ii), wherein: type (i)
NCA monomers comprise NCA-Glu-OR CR (R=alkyl), NCA-Asp-OR
(R=alkyl), NCA forms of hydrophilic neutral amino acids (NCA-AANI),
or mixtures thereof, and type (ii) NCA monomers comprise NCA forms
of hydrophobic neutral amino acids (NCA-AANO), wherein the
copolymerization is in the presence of at least one non-aromatic
polar solvent selected from the group consist of
N-methylpyrrolidone (NMP)), dimethylformamide (DFM), dimethyl
sulfoxide (DMSO), dimethylacetamide (DMAc), pyrrolidone, and
mixtures thereof; and b) precipitating the copolymer to obtain a
particle precursor.
22. A copolymer that is a particle precursor produced by the method
of claim 21.
23. The method of claim 21, whereby step a) further comprises
copolymerization in the presence of at least one cosolvent selected
from the group consisting of aprotic solvents, protic solvents,
water, alcohols, and mixtures thereof.
24. The method of claim 21, whereby the copolymer formed is a
random copolymer with a molecular weight that is .gtoreq.2,000
Da.
25. The method of claim 21, whereby the degree of polymerization is
30-600%.
26. The method of claim 21, whereby the particle size of the
copolymer is 0.01 to 0.5 .mu.M.
27. The method of claim 21, whereby the type (i) NCA monomers are
NCA-Glu-OR and/or NCA-Asp-OR, and whereby the method further
comprises an acid hydrolysis step comprising: c) contact the
copolymer formed with an aqueous phase comprising at least one
amine.
28. The method of claim 27, whereby said step c) is carried out
with water and at least one mineral acid and/or at least one
organic acid.
29. The method of claim 28, whereby the mineral acid is
hydrochloric acid.
30. The method of claim 28, whereby the organic acid is selected
from the group consisting of: trifluoroacetic acid (TFA), acetic
acid, dichloroacetic acid, organosulfonic acids, and mixtures
thereof.
31. The method of claim 27, whereby the proportions of water to
acid, as expressed in parts by water, is 60/1 to 2/1.
32. The method of claim 27, further comprising the step of: d)
dialyzing the reaction medium to obtain an aqueous suspension of
submicron particles comprising the copolymer.
33. The method of claim 32, further comprising the step of: e)
concentrating the aqueous suspension by converting the hydrophilic
part of the glutamate monomers to acid, thereby resulting in acidic
amphiphilic polyamino acids intermediates that are insoluble in
water.
34. The method of claim 33, further comprising the step of: f)
filtering, washing, and drying the acidic amphiphilic polyamino
acids intermediates to thereby obtain a copolymer that is a
particle precursor.
35. A copolymer that is a particle precursor produced by the method
of claim 34.
36. The method of claim 21, whereby the NCA-pAAI is a NCA of
O-alkylated gluatamic or aspartic acid.
37. The method of claim 26, whereby the NCA-pAAI is selected from
the group consisting of: NCA-Glu-O-Methyl, NCA-Glu-O-Ethyl,
NCA-Glu-O-Benzyl, and mixtures thereof.
38. The method of claim 21, whereby the copolymerization takes
place between a temperature of 20 to 120.degree. C., a atmospheric
pressure and in the presence of an amine initiator.
Description
TECHNICAL FIELD
[0001] The present invention relates to the field of carrier
particles (CP) that are useful for the administration of active
principles (AP). The latter are preferably drugs or nutriments for
administration to an animal or human organism by the oral or nasal,
vaginal, ocular, subcutaneous, intravenous, intramuscular,
intradermal, intra-peritoneal, intracerebral, parenteral or other
route. However, they can also be cosmetic products or plant health
products such as herbicides, pesticides, insecticides, fungicides,
etc. In terms of their chemical nature, the AP to which the
invention relates more particularly, but without implying a
limitation, are e.g. proteins, glycoproteins, peptides,
polysaccharides, lipopolysaccharides, oligo-nucleotides,
polynucleotides and organic molecules.
[0002] The present invention relates more precisely to colloidal
suspensions of carrier particles, advantageously of the submicron
type, that are based on polyamino acids (PAA).
[0003] The present invention relates both to bare particles as
such, and to AP carrier systems consisting of the particles loaded
with the AP in question.
[0004] The present invention further relates to pulverulent solids
comprising these CP.
[0005] The invention further relates to methods of preparing said
colloidal suspensions of particles, with or without AP.
PRIOR ART
[0006] The purpose of encapsulating or adsorbing AP in CP is
especially to modify their duration of action and/or convey them to
the treatment site and/or increase the bioavailability of said AP.
Numerous encapsulation techniques have already been proposed. The
aim of such techniques is on the one hand to enable the AP to be
transported to its site of therapeutic action while at the same
time protecting it from the aggressions of the organism
(hydrolysis, enzymatic digestion, etc.), and on the other hand to
control the release of the AP at its site of action so that the
amount available to the organism is maintained at the desired
level. The AP involved in these changes in transport and residence
in the organism are e.g. proteins, but they can also be products
that are quite different from organic molecules of synthetic or
natural origin. The review by M. J. HUMPHREY (Delivery system for
peptide drugs, edited by S. DAVIS and L. ILLUM, Plenum Press, N.Y.
1986) discusses the problem associated with the improvement of AP
bioavailability and the advantage of carrier and controlled release
systems.
[0007] The CP according to the invention are of the type on which
the AP is adsorbed.
[0008] Of all the materials that can be considered for forming CP,
polymers are increasingly widely used because of their intrinsic
properties. The specifications sheet which it is desired to obtain
for the CP is particularly demanding and comprises the following
specifications in particular: [0009] 1 The first specification
sought for the CP would be that the polymer constituting the CP is
biocompatible, capable of elimination (by excretion) and/or
biodegradable, and particularly that it is metabolized to products
that are non-toxic to the organism. In addition, the biodegradation
in the organism should be of a sufficiently short duration. [0010]
2 It would be advantageous for the CP to be able to form a stable
aqueous suspension without the aid of an organic solvent and/or a
surfactant. [0011] 3 It would also be desirable for the CP to be
sufficiently small to be able to undergo, in suspension in a
liquid, a sterilizing filtration with a filter whose pore diameter
is less than or equal to 0.2 .mu.m. [0012] 4 It is desirable for
the CP and the CP-AP systems to be obtainable by a method that is
non-denaturing towards the AP. [0013] 5 The CP should
advantageously make it possible to control the rate of release of
the AP. [0014] 6 Another important specification would be for the
CP-AP systems to be able to constitute excellent injectable drugs.
This improved suitability for administration by injection--e.g.
intravenous or intramuscular injection--or "injectability" is
characterized by: [0015] (i) a reduced injected volume (for a given
therapeutic dose), and [0016] (ii) a low viscosity. [0017] These
two properties are satisfied when the therapeutic dose of AP is
associated with a minimum amount of CP. In other words the CP must
have a high AP loading factor. [0018] 7 The inherent cost of the CP
in an injectable preparation must be reduced and, here again, the
CP should have a high AP loading factor. In fact, the small size
and high loading factor are major specifications sought for the CP.
[0019] 8 It is also advantageous if the constituent polymer of the
CP does not induce an immune response.
[0020] The earlier technical proposals, described below, attempted
to meet all these specifications. The earlier proposals (a) to (h)
will be mentioned by way of illustration: [0021] (a) U.S. Pat. No.
5,286,495 relates to a method of encapsulation by the vaporization
of proteins in the aqueous phase with the aid of materials carrying
opposite charges, namely alginate (negatively charged) and
polylysine (positively charged). This manufacturing process makes
it possible to produce particles with a size above 35 .mu.m. [0022]
(b) Furthermore, emulsion techniques are commonly used to prepare
microparticles loaded with AP. For example, patent applications WO
91/06286, WO 91/06287 and WO 89/08449 disclose such emulsion
techniques in which organic solvents are used to solubilize
polymers, for example of the polylactic type. However, it has been
found that the solvents can be denaturing, especially for peptide
or polypeptide AP. [0023] (c) Biocompatible CP called proteinoids
are also known, having been described since 1970 by X. FOX and K.
DOSE in "Molecular evolution and the origin of life", published by
Marcel DEKKER Inc. (1977). Thus patent application WO 88/01213
proposes a system based on a mixture of synthetic polypeptides
whose solubility depends on the pH. To obtain the matrix
microparticles according to said invention, the authors solubilize
the mixture of polypeptides and then, with a pH change, they cause
proteinoid particles to precipitate. When the precipitation takes
place in the presence of an AP, the latter is encapsulated in the
particle. [0024] (d) U.S. Pat. No. 4,351,337, which relates to a
different field from that of AP transport peculiar to the present
invention, may also be cited as a matter of interest. Said patent
discloses mass implants fixed and localized in very specific places
in the organism. These implants are tubes or hollow capsules of
microscopic size (160 .mu.m, with a length of 2000 .mu.m) which
consist of polyamino acid copolymers--e.g. poly(glutamic
acid/leucine) or poly(benzyl glutamate/leucine)
copolymers--obtained by the copolymerization of amino acid
N-carboxy anhydride (NCA) monomers. An AP is included by a
technique of solvent evaporation from a mixture of polymer and AP.
U.S. Pat. No. 4,450,150 belongs to the same family as U.S. Pat. No.
4,351,337 studied above, and has essentially the same subject
matter. The constituent PAA are poly(glutamic acid/ethyl glutamate)
copolymers. [0025] (e) Patent application EP 0 734 720 relates to
polyamino acid particles that are useful for carrying AP. These
particles have a size of between 10 and 500 nm, preferably of
between 30 and 400 nm. [0026] The particles according to EP 0 734
720 are formed spontaneously when PAA are brought into contact with
an aqueous solution. The PAA include hydrophobic neutral amino acid
monomers, AANO (Leu, Ile, Val, Ala, Pro, Phe), and hydrophilic
ionizable monomers, AAI (Glu, Asp). These PAA are prepared by
copolymerizing NCA of AAI precursors (e.g. Glu-OMe) and NCA of AAO
(e.g. Leu) in solution in a dioxane/toluene mixture. The
poly(Glu-OMe/Leu) copolymer obtained in solution is recovered by
precipitation in water, filtration and drying. This copolymer is
then subjected to acid hydrolysis by being incorporated into
trifluoroacetic acid [0027] (TFA), in which it dissolves. A
poly(Glu-O-Na/Leu) copolymer is recovered after neutralization,
dialysis, filtration and lyophilization. The coPAA is dispersed in
an aqueous solution of NaCl and a suspension of nanoparticles forms
spontaneously. As soon as these CP in aqueous suspension are
brought into contact with an AP, the latter associates
spontaneously with the CP by adsorption. The CP have a hydrophobic
core formed of hydrophobic amino acids and a hydrophilic external
"lattice" based on hydrophilic amino acids. [0028] It is pointed
out that the carrier particles according to EP 0 734 720 contain
ionizable amino acids (Glu) carrying a negative stabilizing
electric charge, making it possible to prevent the particles, CP,
from flocculating and aggregating. [0029] (f) FR-A-2 746 035
relates to microparticles of composite gel that are
physicochemically stable, integral and capable of being used as
active principle carriers. These microparticles consist of oil (I),
aqueous phase (II) and at least one linear, non-crosslinked,
synthetic copolyamino acid (III) containing at least two different
types of amino acid comonomers: hydrophilic, AAI, and hydrophobic,
AAO. The AAI can be Glu, Asp, Orn, Arg, Lys, Asn, His and
associations thereof. The AAO comonomers can be Leu, Tyr, Phe, Val,
Cys, Ile and associations thereof. On page 27, lines 8 to 18, in
particular, FR-A-2 746 035 describes an aqueous colloidal
suspension of polyamino acids, for example poly(leucine/sodium
glutamate) copolymer.
[0030] However, FR-A-2 746 035 does not disclose the use of the
copolymers by themselves as a nanoparticulate pharmaceutical system
for carrying AP.
[0031] The AAI of FR-A-2 746 035 are not hydrophilic neutral amino
acids selected from the group comprising: [0032] the following
natural neutral amino acids: serine, threonine, hydroxyproline,
glutamine; [0033] the following rare or synthetic neutral amino
acids: methionine S-oxide, O-glycosidylserine; and [0034] the
following derivatives of neutral amino acids:
N-hydroxyethyl-glutamine, N-hydroxypropylasparagine.
[0035] All these earlier technical proposals described above:
[0036] either incompletely meet the specifications of the
specifications sheet indicated above, particularly as regards
suitability for sterilization by filtration, high degradation rate,
adaptability to the constraints of drug administration by
injection, low cost and high AP loading factor; [0037] or could be
replaced by novel technical solutions capable of affording novel
advantages (prior art reference EP 0 734 720).
BRIEF DISCLOSURE OF THE INVENTION
[0038] With these facts established, one essential objective is to
be able to provide novel CP which form stable aqueous suspensions
of CP spontaneously, without the aid of surfactants or organic
solvents.
[0039] Another essential objective of the present invention is to
provide novel CP in stable colloidal aqueous suspension or in
pulverulent form, based on polyamino acids (PAA), these novel CP
preferably meeting specifications 1 to 8 of the specifications
sheet mentioned above.
[0040] Another essential objective of the invention is to improve
the particles disclosed in PCT patent application WO 96/29991.
[0041] Another essential objective of the invention is to provide a
novel suspension of CP whose characteristics are perfectly
controlled, especially in terms of the AP loading factor and in
terms of control of the AP release kinetics.
[0042] Another essential objective of the invention is to provide
injectable medicinal suspensions. The specifications required for
such suspensions are a small injection volume and a low viscosity.
It is important that the mass of colloidal particles per injection
dose be as small as possible, without limiting the amount of active
principle, AP, transported by these particles, so as not to detract
from the therapeutic efficacy.
[0043] Another essential objective of the invention is to provide a
colloidal aqueous suspension or a pulverulent solid which comprises
active principle carrier particles meeting the above-mentioned
specifications, and which constitutes an appropriate galenical form
suitable for administration, for example orally, to humans or
animals.
[0044] Another essential objective of the invention is to provide a
colloidal suspension comprising active principle carrier particles
that can be filtered on 0.2 .mu.m filters for sterilization
purposes.
[0045] Another essential objective of the invention is to propose a
method of preparing PAA particles (dry or in suspension in a
liquid) that are useful especially as active principle carriers,
said method being simpler to carry out and non-denaturing towards
the active principles and additionally always allowing fine control
over the mean size of the particles obtained.
[0046] Another essential objective of the invention is to use the
above-mentioned particles, in aqueous suspension or in solid form,
for the preparation of [0047] drugs (e.g. vaccines), especially for
oral, nasal, vaginal, ocular, subcutaneous, intravenous,
intramuscular, intradermal, intraperitoneal, intracerebral or
parenteral administration, it being possible in particular for the
active principles of these drugs to be proteins, glycoproteins,
peptides, polysaccharides, lipopolysaccharides, oligonucleotides
and polynucleotides; [0048] and/or nutriments; [0049] and/or
cosmetic or plant health products; [0050] and/or medicinal organic
molecules.
[0051] Another essential objective of the present invention is to
provide suspensions of submicron CP based on PAA that are capable
of acting as a carrier for an AP, particularly a medicinal AP for
administration to a human or animal organism, or alternatively a
nutritional, plant health or cosmetic AP.
[0052] Another objective of the present invention is to provide a
drug, of the type consisting of a system for the prolonged release
of active principles, which is easy and economic to produce and
which is also biocompatible and capable of assuring a very high
level of bioavailability of the AP.
[0053] Another essential objective of the invention is to provide a
vaccine carrier system which is non-immunogenic intrinsically and
in combination with one or more antigens.
[0054] The product-related objectives (among others) are achieved
by the present invention, which relates first and foremost to a
stable colloidal suspension of submicron structured particles
capable of being used especially for carrying one or more active
principles, AP, these particles being individualized (discrete)
supramolecular arrangements that are: [0055] based on linear
amphiphilic polyamino acids (PAA) having peptide linkages and
comprising at least two different types of hydrophilic repeating
amino acids, AAI, and hydrophobic repeating amino acids, AAO, the
amino acids of each type being identical to or different from one
another; [0056] capable of associating at least one AP in colloidal
suspension, in the undissolved state, and releasing it, especially
in vivo, in a prolonged and/or delayed manner; [0057] and stable in
the aqueous phase at a pH of between 4 and 13, in the absence of
surfactant(s), characterized: [0058] in that the hydrophilic
repeating amino acids, AAI, are hydrophilic neutral amino acids,
AANI, with the exclusion of asparagine; [0059] in that the
hydrophobic repeating amino acids, AAO, are hydrophobic neutral
amino acids, AANO; [0060] and in that the repeating amino acids of
each type, AANI and AANO, are identical to or different from one
another.
DETAILED DISCLOSURE OF THE INVENTION
[0061] One of the main inventive aspects of these novel carrier
particles, CP, in stable colloidal aqueous suspension or in the
form of a pulverulent solid, concerns the novel selection of a
group of polymers and a novel methodology for obtaining particles
of submicron size which form a stable colloidal aqueous suspension
in the absence of surfactants or solvents.
[0062] Another main inventive aspect of these novel carrier
particles, CP, in stable colloidal aqueous suspension or in the
form of a pulverulent solid, concerns the novel selection of two
neutral amino acids as hydrophilic repeating monomers, AANI, and
hydrophobic repeating monomers, AANO.
[0063] Now, contrary to what those skilled in the art might have
feared, not having ionizable hydrophilic amino acids, AAII, i.e.
negative charges, as in the particles according to WO 96/29991,
does not detract from the stability. In fact, contrary to all
expectations, the colloidal suspension according to the present
invention does not flocculate. The particles based
on-poly(AANI/AANO) do not self-aggregate. Moreover, it was not at
all obvious a priori that these particles of poly(AANI/AANO) would
be capable of associating spontaneously with active principles, AP,
and releasing these AP at the sites of therapeutic action.
[0064] The structure of the PAA polymers and the nature of the
neutral amino acids are chosen so that: [0065] the polymer chains
spontaneously organize themselves into small particles (CP); [0066]
the particles form a stable colloidal suspension in water and in a
physiological medium; [0067] the CP associate with proteins or
other AP in aqueous media by a spontaneous mechanism that is
non-denaturing towards the protein; and [0068] the CP release the
AP in a physiological medium and, more precisely, in vivo; the
release kinetics depend on the nature of the PAA polymer that is
the CP precursor.
[0069] Thus, by varying the specific structure of the PAA, it is
possible to control the AP association and release phenomena from
the kinetic and quantitative points of view.
[0070] It is to the Applicant's credit to have chosen, as the
constituent material of the CP, a specific composition of neutral
polyamino acids which are amphiphilic and therefore possess
properties of CP made of PAA, namely: [0071] the possibility of
spontaneously forming colloidal suspensions of CP that are
compatible with the pH of the physiological media encountered in
the intended therapeutic applications; [0072] spontaneous
association of the AP with CP in the absence of any agent other
than water, which acts as solvent and, in the case of proteins, is
non-denaturing; [0073] the possibility of releasing the AP from the
AP-CP association complex under physiological conditions with
pharmacokinetic and pharmaco-dynamic profiles which lead to the
expectation of valuable uses in the therapeutic field (AP
transport); [0074] filterability with a cut-off threshold less than
or equal to 0.2 .mu.m for sterilization purposes; [0075] improved
biodegradability; and [0076] optimized injectability.
[0077] These PAA can be of the ordered type with alternate
sequences (blocks) or of the disordered type with random
sequences.
[0078] Thus, in a first embodiment of the CP according to the
invention, the constituent PAA are of the "block" type and are
characterized by a molar ratio AANO/(AANI+AANO) which is such that:
[0079] AANO/(AANI+AANO).gtoreq.6%, [0080]
10%.ltoreq.AANO/(AANO+AANI).ltoreq.70%, [0081] preferably,
20%.ltoreq.AANO/(AANI+AANO).ltoreq.60%, [0082] and particularly
preferably, 35%.ltoreq.AANO/(AANI+AANO).ltoreq.50%.
[0083] Advantageously, the absolute length of each block of AANO,
expressed as the number of AANO, is such that: [0084]
AANO.gtoreq.5, [0085] preferably, AANO.gtoreq.10, [0086] and
particularly preferably, AANO.gtoreq.20.
[0087] In a second embodiment of the CP according to the invention,
the constituent PAA are of the "random" type, i.e. prepared by the
simultaneous copolymerization of AANI and AANO monomers, and the
molar ratio AANO/(AANO+AANI) is such that: [0088]
AANO/(AANO+AANI).gtoreq.10%, [0089] preferably,
AANO/(AANO+AANI).gtoreq.20%, [0090] and particularly preferably,
30%.ltoreq.AANO/(AANI+AANO).ltoreq.70%.
[0091] Advantageously, the molecular weight, Mw, of these random
PAA is such that: [0092] Mw.gtoreq.2000 g/mol, [0093] preferably,
Mw.gtoreq.5500 g/mol, [0094] and particularly preferably, 5500
g/mol.ltoreq.Mw.ltoreq.200,000 g/mol.
[0095] According to a preferred characteristic of the invention,
the block or random PAA constituting the particles have degrees of
polymerization, DP, of between 30 and 600, preferably of between 50
and 200 and particularly preferably of between 60 and 150.
[0096] Advantageously, the PAA constituting the particles, CP, are
"di-block" PAA.
[0097] Preferably, the hydrophilic AANI is (are) selected from the
group comprising: [0098] natural neutral amino acids, preferably
those selected from the group comprising serine, threonine,
hydroxyproline and glutamine; [0099] the rare or synthetic neutral
amino acids, preferably those selected from the group comprising
methionine S-oxide and O-glycosidylserine; and [0100] derivatives
of neutral amino acids, preferably those selected from the group
comprising N-hydroxyethylglutamine, N-hydroxypropylasparagine,
N-hydroxyethylasparagine and N-hydroxypropylglutamine.
[0101] Advantageously, the hydrophobic AANO is (are) selected from
the group comprising: [0102] natural neutral amino acids,
preferably those selected from the group comprising Leu, Ile, Val,
Ala, Pro and Phe; [0103] rare or synthetic neutral amino acids,
preferably those selected from the group comprising norleucine and
norvaline; and [0104] derivatives of polar amino acids, preferably
those selected from the group comprising methyl glutamate, ethyl
glutamate, benzyl aspartate and N-acetyllysine.
[0105] According to an advantageous characteristic, the carrier
particles (CP) of the suspension have a mean size of between 0.01
and 0.5 .mu.m, preferably of between 0.01 and 0.2 .mu.m.
[0106] Another preferred characteristic of the suspension is that
it is aqueous and stable.
[0107] The present invention relates not only to suspensions of
bare particles as defined above, but also to suspensions of
particles comprising at least one active principle, AP. Preferably,
the suspension according to the invention is aqueous and stable.
These particles, whether loaded with AP or not, are advantageously
in a form dispersed in a liquid (suspension), preferably an aqueous
liquid, but can also be in the form of a pulverulent solid obtained
from the suspension of CP as defined above.
[0108] It follows from this that the invention relates not only to
a colloidal (preferably aqueous) suspension of CP, but also to a
pulverulent solid comprising CP which is obtained from the
suspension according to the invention.
[0109] Another essential object of the invention concerns the
preparation of: [0110] selected particles as described above;
[0111] and other selected particles which are structured, submicron
and capable of being used especially for carrying one or more
active principles, AP, these particles being individualized
(discrete) supramolecular arrangements that are: [0112] based on
linear amphiphilic polyamino acids (PAA) having peptide linkages
and comprising at least two different types of hydrophilic
repeating amino acids, AAI, and hydrophobic repeating amino acids,
AAO, the amino acids of each type being identical to or different
from one another; [0113] capable of associating at least one AP in
colloidal suspension, in the undissolved state, and releasing it,
especially in vivo, in a prolonged and/or delayed manner; [0114]
and stable in the aqueous phase at a pH of between 4 and 13, in the
absence of surfactant(s), where: [0115] the hydrophilic repeating
amino acids, AAI, consist at least partly of asparagine; [0116] and
the hydrophobic repeating amino acids, AAO, are hydro-phobic
neutral amino acids, AANO, which are identical to or different from
one another, it being possible for these particles to be either in
the form of a colloidal suspension or in the form of a pulverulent
solid obtained from a stable colloidal suspension of particles.
[0117] The method of preparation in question consists essentially
in synthesizing precursor PAA and converting them to structured
particles.
[0118] More precisely, the method of preparation is first and
foremost a method of preparing submicron structured particles
capable of being used especially for carrying one or more active
principles, these particles being discrete supramolecular
arrangements that are: [0119] based on linear amphiphilic polyamino
acids (PAA) having peptide linkages and comprising at least two
different types of hydrophilic repeating amino acids, AAI, and
hydrophobic repeating amino acids, AAO, the amino acids of each
type being identical to or different from one another; [0120]
capable of associating at least one AP in colloidal suspension, in
the undissolved state, and releasing it, especially in vivo, in a
prolonged and/or delayed manner; [0121] and stable in the aqueous
phase at a pH of between 4 and 13, in the absence of
surfactant(s).
[0122] This method is characterized in that: [0123] 1) a
copolymerization is carried out between monomers formed of amino
acid N-carboxy anhydrides (NCA) of at least two different types:
[0124] on the one hand starting NCA monomers comprising NCA-Glu-OR
and/or NCA-Asp-OR and/or NCA-AANI, [0125] and on the other hand
NCA-AANO, in the presence of: [0126] at least one non-aromatic
polar solvent preferably selected from the group comprising
N-methylpyrrolidone (NMP), dimethylformamide (DMF), dimethyl
sulfoxide (DMSO), dimethylacetamide (DMAc) and pyrrolidone, NMP
being more particularly preferred; [0127] and optionally at least
one cosolvent selected from aprotic solvents (preferably
1,4-dioxane) and/or protic solvents (preferably pyrrolidone) and/or
water and/or alcohols, methanol being particularly preferred;
[0128] 2) in the case where the starting NCA monomers are
NCA-Glu-OR and/or NCA-Asp-OR(R=alkyl), an aminolysis is carried out
which consists in bringing the copolymer obtained in step 1 into
contact with an aqueous phase comprising at least one amine, and
which makes it possible to convert Glu-OR to Gln and Asp-OR to Asn;
[0129] 3) the reaction medium is optionally dialyzed to purify the
aqueous suspension of structured particles; [0130] 4) this
suspension of step 3 is optionally concentrated; and [0131] 5) the
liquid medium is removed so that the pulverulent solid comprising
the particles can be collected.
[0132] The first step of the method is based on the known
techniques of polymerizing .alpha.-amino acid N-carboxy anhydrides
(NCA), which are described for example in the article "Biopolymers,
15, 1869 (1976)" and in the work by H. R. KRICHELDORF entitled
".alpha.-Amino acid N-carboxy anhydride and related heterocycles",
Springer Verlag (1987).
[0133] Using carefully chosen polar, non-aromatic aprotic
copolymerization solvents that avoid any precipitation, and using
acid hydrolysis in the presence of water and a non-aromatic, polar
organic solvent, affords submicron, discrete structured particles
with a high AP loading capacity which form a stable colloidal
suspension in aqueous media. These particles are in no way
comparable to a macroscopic agglomerated precipitate of the kind
referred to above in respect of earlier proposal (d).
[0134] In one variant, after step 1, the poly(AANO/AANI) copolymer
obtained is precipitated--preferably in water--and this precipitate
is collected. This variant corresponds to a batch mode of preparing
particles in which the poly-(AANO/AANI) copolymer is isolated in
the form of a precipitate constituting a stable intermediate. This
precipitate can be filtered off, washed and dried, for example.
[0135] Particularly preferably, the NCA-pAAI are NCA of O-alkylated
glutamic or aspartic acid, for example NCA-Glu-O-Me, NCA-Glu-O-Et
or NCA-Glu-O-Bz (Me=methyl-Et=ethyl-Bz=benzyl).
[0136] In known manner, the copolymerization takes place at a
temperature of between 20 and 120.degree. C., at atmospheric
pressure and in the presence of an amine initiator, e.g.
NH.sub.3.
[0137] Other experimental parameters, such as the concentration of
NCA and/or polymer in the non-aromatic polar solvent (preferably
NMP) and/or the concentration or nature of the protic cosolvent,
during the synthesis, will be adjusted according to the desired
effects known to those skilled in the art.
[0138] The acid hydrolysis (step 2) is carried out with water and
at least one mineral acid such as phosphoric or hydrochloric
acid--the latter being preferred--and/or at least one organic acid
such as trifluoroacetic acid (TFA), acetic acid, dichloroacetic
acid or organosulfonic acids.
[0139] The proportions of water/acid--expressed in parts by
weight--in an acidic aqueous hydrolysis phase are advantageously:
[0140] from 60/1 to 2/1, [0141] preferably 40/1 to 2/1, [0142] and
particularly preferably 20/1 to 2/1.
[0143] The proportions of acidic aqueous hydrolysis
phase/NMP--expressed in parts by weight--are advantageously: [0144]
from 5/100 to 200/100, [0145] preferably 10/100 to 100/100, [0146]
and particularly preferably from 20/100 to 80/100.
[0147] Other parameters, such as the polymer concentration, the
temperature of the reaction mixture, the mode of addition of the
acidic aqueous hydrolysis phase, the use of reduced pressure, the
reaction time, etc., are adjusted according to the desired effects
well known to those skilled in the art.
[0148] In practice, the neutralization (step 3) is carried out e.g.
with sodium hydroxide. The salt formed at the end of the
neutralization, and the solvent, are then removed by any
appropriate physical separation treatment, for example by
diafiltration (dialysis) (step 4), filtration, pH modification,
chromatography, etc.
[0149] This yields an aqueous suspension of structured particles
which can be concentrated, for example by distillation or any other
suitable physical means such as ultrafiltration or
centrifugation.
[0150] In step 6, to separate the particles from their liquid
suspension medium, the aqueous phase is optionally removed, for
example by drying (e.g. in an oven), lyophilization or any other
suitable physical means such as ultrafiltration or centrifugation.
A white pulverulent solid is recovered at the end of this step
6.
[0151] In one variant, the concentration step can be carried out by
means of a chemical treatment, such as a lowering of the pH, which
converts the hydrophilic part of the glutamate monomers to acid,
making them insoluble in water. These acidic PAA intermediates can
be filtered off, washed and dried. Said acidic intermediates can be
neutralized with a chemical base in a subsequent step to give a
suspension of particles.
[0152] It is pointed out that the implementation of steps 1, 2, 3,
4 and optionally 5 of the above method corresponds to a preparation
of a colloidal suspension of submicron particles with a high AP
loading factor.
[0153] In this preparation of a colloidal suspension, the
amphiphilic PAA, poly(AANO/AANI), of step 2 are placed in an
aqueous medium in which at least part of the AANI is soluble and at
least part of the AANO is insoluble. The PAA exist in the form of
nanoparticles in this aqueous medium.
[0154] An alternative preparation of the suspension of CP according
to the invention consists in bringing the pulverulent solid, as
described above as a product and by its method of preparation, into
contact with an aqueous medium that is a non-solvent for the
AANO.
[0155] One or more AP can be associated with the particles by using
several methods according to the invention. Non-limiting examples
of these methods are listed below.
[0156] According to a first method, an AP is associated with the
particles by bringing a liquid phase (aqueous or non-aqueous)
containing the AP into contact with the colloidal suspension of
particles which may or may not comprise Asp as AANI.
[0157] According to a second method, the AP is associated with the
particles by bringing an AP in the solid state into contact with
the colloidal suspension of particles which may or may not comprise
Asp as AANI. The solid AP can be e.g. in the form of a
lyophilizate, precipitate or powder or in another form.
[0158] According to a third method, the pulverulent solid (PAA
which may or may not comprise Asp as AANI), as described above as a
product and by its preparative characteristics, is brought into
contact with a liquid phase (aqueous or non-aqueous) containing the
AP.
[0159] According to a fourth method, the pulverulent solid, as
described above as a product and by its preparative characteristics
(PAA which may or may not comprise Asp as AANI), is brought into
contact with the AP in solid form. This mixture of solids is then
dispersed in a liquid phase, preferably an aqueous solution.
[0160] In all these methods, the AP used can be in the pure form or
a preformulated form.
[0161] Given the nanometric size of the particles, the suspension
can be filtered on sterilization filters, enabling sterile
injectable medicinal liquids to be obtained easily and at lower
cost. The ability, afforded by the invention, to control the
particle size and reach Dh values of between 25 and 100 nm is an
important asset.
[0162] The present invention further relates to novel intermediates
of the method described above, characterized in that they consist
of PAA copolymers (which may or may not comprise Asp as AANI) that
are particle precursors.
INDUSTRIAL APPLICATION
[0163] According to another of its features, the invention relates
to a suspension and/or a pulverulent solid (PAA which may or may
not comprise Asp as AANI) as defined above and/or as obtained by
the method described above, this suspension and this solid
comprising at least one active principle preferably selected from:
[0164] vaccines; [0165] proteins and/or peptides, among which the
following are more preferably selected: hemoglobins, cytochromes,
albumins, interferons, antigens, antibodies, erythropoietin,
insulin, growth hormones, factors VIII and IX, interleukins or
mixtures thereof, and hemopoiesis-stimulating factors; [0166]
polysaccharides, heparin being more particularly selected; [0167]
nucleic acids and preferably RNA and/or DNA oligonucleotides;
[0168] non-peptido-protein molecules belonging to various
anticancer chemotherapy categories, particularly anthracyclines and
taxoids; [0169] and mixtures thereof.
[0170] The invention further relates to a suspension and/or a
pulverulent solid (PAA which may or may not comprise Asp as AANI)
loaded with a nutritional, plant health or cosmetic AP.
[0171] Finally, the invention relates to a pharmaceutical,
nutritional, plant health or cosmetic proprietary product,
characterized in that it contains a suspension and/or pulverulent
solid as defined above, loaded with AP.
[0172] According to another of its objects, the invention further
relates to the use of these CP (in suspension or in solid form: PAA
which may or may not comprise Asp as AANI), loaded with AP, for the
manufacture of drugs of the type consisting of systems for the
controlled release of AP.
[0173] In particular, the invention relates to the use of a stable
colloidal suspension of submicron structured particles loaded with
one or more active principles, AP, these particles being
individualized (discrete) supramolecular arrangements that are:
[0174] based on linear amphiphilic polyamino acids (PAA) having
peptide linkages and comprising at least two different types of
hydrophilic repeating amino acids, AAI, and hydrophobic repeating
amino acids, AAO, the amino acids of each type being identical to
or different from one another; [0175] capable of associating at
least one AP in colloidal suspension, in the undissolved state, and
releasing it, especially in vivo, in a prolonged and/or delayed
manner; [0176] and stable in the aqueous phase at a pH of between 4
and 13, in the absence of surfactant(s), where: [0177] the
hydrophilic repeating amino acids, AAI, consist at least partly of
asparagine; [0178] and the hydrophobic repeating amino acids, AAO,
are hydrophobic neutral amino acids, AANO, which are identical to
or different from one another, for the preparation of an aqueous
suspension or a pulverulent solid as above defined, loaded with at
least one AP.
[0179] Examples of drugs are those that can preferably be
administered by the oral, nasal, vaginal, ocular, subcutaneous,
intravenous, intramuscular, intradermal, intra-peritoneal,
intracerebral or parenteral route.
[0180] Examples of cosmetic applications that can be considered are
compositions which comprise an AP associated with the CP according
to the invention and which can be administered transdermally.
[0181] Examples of possible plant health products are herbicides,
pesticides, insecticides, fungicides, etc.
[0182] The Examples which follow will provide a better
understanding of the invention according to its different
product/method/application features. These Examples illustrate the
preparation of particles of polyamino acids which may or may not be
loaded with active principles, and also present the structural
characteristics and the properties of these particles.
EXAMPLES
Example 1
Preparation of Poly(Leucine/Methyl Glutamate) Block Copolymer
[0183] The techniques used to polymerize NCA to polymers with block
or random structures are known to those skilled in the art and are
described in detail in the work by H. R. KRICHELDORF entitled
".alpha.-Amino acid N-carboxy anhydrides and related heterocycles",
Springer Verlag (1987). The synthesis of one such polymer is
specified below.
[0184] Synthesis of poly(Leu).sub.40poly(GluOMe).sub.80: 10 g of
NCA-GluOMe are solubilized in 150 ml of NMP at 60.degree. C. 5 ml
of a solution of 0.91 g of benzylamine in 50 ml of NMP are added
all at once to the monomer. After 1 h, 14.1 g of NCA-Leu,
previously solubilized in 20 ml of NMP, are added. Polymerization
continues for a further 3-4 h.
[0185] Sampling of the reaction medium affords the following
characterizations: Yield: 90%. Composition by .sup.1H NMR (TFA-d):
66 mol % of GluOMe. Reduced viscosity (0.5% of TFA at 25.degree.
C.): 0.4 dl/g. Molecular weight by GPC: 20,000 g/mol.
Example 2
Aminolysis of Poly(Leucine/Methyl Glutamate) Block Copolymer with
Hydroxyethylamine
[0186] 10 g of hydroxyethylamine are added all at once to the NMP
solution of polymer prepared according to Example 1. The medium is
heated to 80.degree. C. and kept at this temperature for 2 days.
150 ml of water are then added to the polymer solution, which is
then purified by a dialysis step to ensure removal of the excess
amine and the NMP. Finally, the particles are isolated by
lyophilization.
[0187] Yield: quantitative. .sup.1H NMR (TFA-d): 8% of residual
methoxy (3.5 ppm); 92% of hydroxyethylglutamine. Composition by
.sup.1H NMR (TFA-d): 34% of Leu. Particle size (light scattering,
QLS mode): 100 nm.
Example 3
Demonstration of Nanoparticles by Light Scattering (LS) and
Transmission Electron Microscopy (TEM)
[0188] 10 mg of particles of polymer 1 are suspended in 10 ml of
water or an aqueous solution of salt. This solution is then
introduced into a Coulter granulometer (or laser diffractometer).
The results of particle size analysis of the different products
tested are shown in Table 1 below. TABLE-US-00001 TABLE 1
Measurement of the size of the CP Example Polymer Size (nm) 2
poly[(Leu).sub.0.66]-poly[(Gln-N- 100 hydroxyethyl).sub.0.37].sub.x
block copolymer
Example 4
Test of Association of Nanoparticles with a Protein (Insulin)
[0189] An isotonic phosphate buffer solution of pH 7.4 is used to
prepare a solution of human insulin containing 1.4 mg/ml,
corresponding to 40 IU/ml. 10 mg of the CP prepared in Example 1
are dispersed in 1 ml of this insulin solution. After 15 hours of
incubation at room temperature, the insulin associated with the CP
and the free insulin are separated by centrifugation (60,000 g, 1
hour) and ultrafiltration (filtration cut-off: 300,000 D). The free
insulin recovered from the filtrate is assayed by HPLC or ELISA and
the amount of associated insulin is deduced by difference. The
amount of insulin associated with the CP is greater than 0.77 mg,
representing more than 55% of the total insulin used.
[0190] The Table below collates the results of the measurements of
degree of association performed on different CP. The degree of
association expresses the percentage of associated insulin relative
to the insulin used in a preparation containing 1.4 mg/ml of
insulin and 10 mg/ml of CP. This value is converted to a loading
factor which expresses a formulation with 100% protein binding, in
mg of insulin per 100 mg of CP. TABLE-US-00002 TABLE 2 Measurement
of the degree of association with insulin for a mixture of 0.14 mg
INSULIN/mg CP Degree of Loading association factor Example Polymer
(%) mg/100 mg CP 2 poly[(Leu).sub.0.66]-poly[(Gln- 99 13.6
N-hydroxyethyl).sub.0.37].sub.x block copolymer
Example 5
Pharmacokinetics and Pharmacodynamics of Insulin-Loaded CP in
Fasted Healthy Dogs
[0191] The particle+insulin preparation of Example 4 was injected
into dogs which had been rendered diabetic by total pancreatectomy
and fasted since the previous evening. At 11 am the preparation was
administered subcutaneously into the thorax at a dose of 0.5 IU of
insulin per kg of live weight of the animal. The volume
administered is between 0.18 and 0.24 ml. At the times -4, -2, 0,
1, 2, 4, 6, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44 and 48 hours, 1
ml of blood is taken by jugular puncture under vacuum into a sodium
heparinate tube. 30 .mu.l of whole blood are used immediately to
measure the glycemia. The tube is then centrifuiged, the
supernatant is decanted and the plasma is stored at -20.degree. C.
to assay the insulin. The results shown in FIG. 1 below show that
the insulin is released up to 12 hours (solid line) and that there
is a substantial hypoglycemic effect extending up to 20 hours
(broken line) after injection. TABLE-US-00003 TABLE 3 Measurement
of the duration of action of insulin (hypoglycemic effect) in the
presence of CP according to the invention Time to return to Example
Polymer basal level (h) soluble insulin (without CP) 1 2
poly[(Leu).sub.0.66]-poly[(Gln-N- 20 hydroxyethyl).sub.0.37].sub.x
block copolymer
[0192] This Example demonstrates the non-denaturation of insulin in
the presence of CP according to the invention.
[0193] Also, Example 2 makes it possible to demonstrate the
increase in the duration of action of insulin compared with
non-formulated insulin, and hence the usefulness of the CP as a
delaying system for the controlled release of insulin. It also
shows how it is possible to control the duration of action by the
appropriate choice of hydrophobic group.
Example 6
Aminolysis of Poly(Phenylalanine/Methyl Glutamate) Block Copolymer
with Hydroxyethylamine
[0194] 10 g of hydroxyethylamine are added all at once to the NMP
solution of polymer prepared according to Example 1 using the
monomers NCA-GluOMe and NCA-phenylalanine. The medium is heated to
80.degree. C. and kept at this temperature for 2 days. 150 ml of
water are then added to the polymer solution, which is then
purified by a dialysis step to ensure removal of the excess amine
and the NMP. Finally, the particles are isolated by
lyophilization.
[0195] Yield: quantitative. .sup.1H NMR (TFA-d): 6% of residual
methoxy (3.5 ppm); 94% of hydroxyethylglutamine. Composition by
.sup.1H NMR (TFA-d): 34% of Leu. Particle size (light scattering,
QLS mode): 100 nm.
Example 7
Aminolysis of Poly(Leucine/Benzyl Glutamate) Block Copolymer with
3-aminopropylene-1,2-glycol
[0196] 10 g of 3-aminopropylene-1,2-glycol are added all at once to
the NMP solution of polymer prepared according to Example 1 using
the monomers NCA-GluOBzl and NCA-Leu. The medium is heated at
80.degree. C. for 2 days. 150 ml of water are then added to the
polymer solution, which is then purified by a dialysis step to
ensure removal of the excess amine and the solvent. Finally, the
particles are isolated by lyophilization.
[0197] Yield: quantitative. Particle size (QLS, according to
Example 3): 100 nm.
Example 8
Test of Association of Nanoparticles with a Protein (Insulin)
[0198] According to Example 4, the isolated particles of Example 6
and human insulin are used to give a loading factor expressed in mg
of insulin per 100 mg of CP. TABLE-US-00004 Loading Degree of
factor in Example Polymer association mg/100 mg CP 6
poly[(Phe).sub.0.79]-poly[(Gln- 99 8.5
N-dihydroxypropyl).sub.0.21].sub.x block copolymer 7
poly[(Leu).sub.0.66]-poly[(Gln- 99 13.7
N-dihydroxypropyl).sub.0.33].sub.x block copolymer
* * * * *