U.S. patent application number 12/912441 was filed with the patent office on 2011-03-17 for method of preparing macromolecule deterrent surface on a pharmaceutical packages.
Invention is credited to Hartmut Bauch, Matthias Bicker, Jasmina Buki, Luis Burzio, Daniel HAINES, Robert Hormes, Horst Koller, Manfred Lohmeyer.
Application Number | 20110062047 12/912441 |
Document ID | / |
Family ID | 38110714 |
Filed Date | 2011-03-17 |
United States Patent
Application |
20110062047 |
Kind Code |
A1 |
HAINES; Daniel ; et
al. |
March 17, 2011 |
Method Of Preparing Macromolecule Deterrent Surface On a
Pharmaceutical Packages
Abstract
A method of preparing a macromolecule deterrent surface on a
pharmaceutical package. In particular, the present invention
relates to a method of preparing a protein deterrent surface on a
pharmaceutical package by applying a coating or coatings directly
to the pharmaceutical package that reduces the adsorption of
proteins onto pharmaceutical packaging while not affecting the
activity of the protein solution contained.
Inventors: |
HAINES; Daniel; (Lake Ariel,
PA) ; Burzio; Luis; (Wentzville, MO) ; Bicker;
Matthias; (Mainz, DE) ; Hormes; Robert;
(Wolfertswil, CH) ; Koller; Horst; (Engelburg,
CH) ; Buki; Jasmina; (St. Gallen, CH) ; Bauch;
Hartmut; (Weilrod, DE) ; Lohmeyer; Manfred;
(Nackenheim, DE) |
Family ID: |
38110714 |
Appl. No.: |
12/912441 |
Filed: |
October 26, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11649361 |
Jan 4, 2007 |
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12912441 |
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60757863 |
Jan 11, 2006 |
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60795596 |
Apr 28, 2006 |
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Current U.S.
Class: |
206/524.6 |
Current CPC
Class: |
A61J 1/05 20130101; A61L
31/10 20130101; Y10T 428/1307 20150115; B05D 1/62 20130101; A61L
27/34 20130101; B05D 7/22 20130101; A61L 29/085 20130101; Y10T
428/13 20150115; A61L 2400/10 20130101 |
Class at
Publication: |
206/524.6 |
International
Class: |
B65D 85/00 20060101
B65D085/00 |
Claims
1-11. (canceled)
12. A pharmaceutical package having a macromolecule deterrent
surface prepared by a method comprising: depositing a coating that
deters macromolecule adsorption onto the surface of a
pharmaceutical package by plasma chemical vapor deposition (CVD),
wherein said pharmaceutical package acts as a coating chamber and
wherein said coating is formed from a precursor compound containing
carbon-oxygen bonding, wherein said coating reduces the adsorption
of macromolecules to said surface by >25% compared to the
adsorption on the uncoated surface.
13. A pharmaceutical package according to claim 12, wherein said
coating is applied with a source of electromagnetic radiation.
14. A pharmaceutical package according to claim 12, wherein said
coating is prepared from one or more chemical precursors.
15. A pharmaceutical package according to claim 14, wherein one or
more of said precursors are an ether.
16. A pharmaceutical package according to claim 14, wherein one or
more of said precursors are an ester.
17. A pharmaceutical package according to claim 14, wherein said
precursor contains one or more halogen, alkyl, vinyl, alkynyl,
aromatic, hydroxylic, acid, carbonyl, aldehyde, ketone, amine,
amino, amide, nitro or sulfonyl derivatized functional groups.
18. A pharmaceutical package according to claim 14, wherein said
precursor contains one or more halogen, alkyl, vinyl, alkynyl,
aromatic, hydroxylic, acid, carbonyl, aldehyde, ketone, amine,
amino, amide, nitro, sulfonyl derivatized functional groups.
19. A pharmaceutical package according to claim 14, where said
precursor is a polyether.
20. A pharmaceutical package according to claim 19, wherein said
polyether is diglyme, a triglyme, a tetraglyme, a pentaglyme, a
hexaglyme, or a functionalized derivative thereof.
21. A pharmaceutical package according to claim 14, wherein said
precursor is tetraethylene glycol dimethyl ether.
22. A pharmaceutical package according to claim 14, wherein
multiple precursors are deposited either simultaneously or in
sequence.
23. A pharmaceutical package according to claim 14, wherein the
precursor is applied over a first inorganic oxide layer
coating.
24. A pharmaceutical package according to claim 2, wherein said
inorganic oxide is SiO.sub.2, TiO.sub.2, ZrO.sub.2 or
Al.sub.2O.sub.3.
25. A pharmaceutical package according to claim 14, wherein said
precursor is applied over a first adhesion layer.
26. A pharmaceutical package according to claim 14, wherein the
precursor is applied over a first barrier layer.
27. A pharmaceutical package according to claim 14, wherein said
macromolecule is a naturally occurring or synthetically prepared
biomolecule or a derivative thereof in solution or solid state.
28. A pharmaceutical package according to claim 27, wherein one or
more macromolecule is a nucleic acid, polynucleotide, protein,
peptide, carbohydrate, protein/nucleic acid complex, antibody,
vaccine, in solution or solid state.
29-31. (canceled)
32. A pharmaceutical package having a macromolecule deterrent
surface prepared by a method comprising: depositing a coating that
deters macromolecule adsorption onto the surface of a
pharmaceutical package by plasma chemical vapor deposition (CVD),
wherein said pharmaceutical package acts as a coating chamber and
wherein said coating is formed from a precursor compound containing
carbon-oxygen bonding, wherein said coating is applied with pulsed
electromagnetic radiation, with low or high frequency energy of
40-100 kHz, 13.56 MHz or 2.45 GHz.
33-42. (canceled)
Description
[0001] This application claims the benefit of the filing date of
U.S. Provisional Application Ser. No. 60/757,863 filed Jan. 11,
2006 and Ser. No. 60/795,596 and Apr. 28, 2006.
INTRODUCTION
[0002] This invention pertains to an improved method of preparing a
macromolecule (e.g., protein) deterrent surface on a pharmaceutical
package. The coating that deters macromolecular (e.g., protein)
adsorption is applied to pharmaceutical packaging materials by
plasma chemical vapor deposition. One significant growth area in
the pharmaceutical industry is the increasing prevalence of protein
based drug formulations. As proteins have a strong affinity for the
surface of native packaging materials (e.g., glass, polymers), this
results in the loss the active pharmaceutical ingredient by
interaction of the protein to the surface leading to permanent
immobilization and/or denaturation. For mass produced protein based
drugs like insulin the accepted solution is to compensate for the
protein loss by overfilling--using a higher than needed
concentration and/or volume to provide enough product to passivate
the surface and still maintain the required dosage. With the advent
of more specialized (expensive) protein based drugs, the increased
costs to overfill the packaging container are undesirable both to
the manufacturer and consumer.
[0003] The adsorption of macromolecules and in particular proteins
to a surface depends on a variety of factors: substrate surface
chemistry (functional groups present on a native surface or coating
thereon), surface figure (flatness, roughness), the structure of
the protein (molecular weight, distribution of amino acids,
isoelectric point), and the excipients (binders, disintegrants,
diluents, suspension and dispersing agents) present in the protein
formulations. The chemically heterogeneous structure of proteins
allows for surface interaction through hydrogen bonding and a
variety of interaction mechanisms (ionic, hydrophobic, Van der
Waals forces, entanglement, etc.). To mitigate binding through
these mechanisms most protein drug formulators rely on various
excipients such as carbohydrates (e.g., trehalose, sucrose),
buffers systems (e.g., phosphate, tris, citrate) and surfactants
(e.g., polysorbate-80 or polysorbate-20). Though these approaches
may be well established they are not always possible for different
proteins whose activities may be modified by the addition of
excipients resulting in the need for each formulation to be tested
for stability of the protein drug contained in the package and the
effect of the protein adsorption quantified in terms of loss of
protein and protein activity.
[0004] Another approach to deter proteins binding to the surface of
the package is the application of coatings to the package surface,
provided it is feasible in a pharmaceutical packaging scenario (low
cost, sterilizable by 1 or more of the accepted methods of
autoclaving/EtO exposure/gamma irradiation/electron beam
irradiation, non-toxic, 2-3 year stability, 100% coating deposition
verifiable, etc.). A large body of literature has established a set
of generally accepted theoretical parameters (Ostuni E., Chapman R.
G., Holmin R. E., Takayama S., Whitesides G. M. Langmuir 2001, 17,
5605-5620) that determine if a surface is likely to deter protein
adsorption. In general, a surface that is non-ionic, hydrophilic
and hydrogen bond accepting is considered an ideal surface to repel
protein adsorption at the liquid/solid interface. The coating
should also be sterically hindering to the proteins interaction
with the pharmaceutical package and/or component(s) surface (glass,
polymer, copolymer, metal, alloys) to avoid not only adsorption,
but also denaturation. Other theories have been proposed in the
literature to explain the ability of certain coatings to reduce
protein adsorption--for instance, see Gombotz et al (Gombotz W. R.,
Wang G. H., Horbett T. A., Hoffmann A. S. J. Biomed. Mater. Res.
1991, 12, 1547-1562), who postulate that the effectiveness of a
coating (in this case polyethylene oxide) to structure water at the
coating/water interface region influences the ability of a coating
to reduce protein adsorption.
[0005] There is a wealth of general knowledge regarding surfaces
and or coatings that resist protein adsorption. A non-exhaustive
list include polyethylene oxide/glycol-like and other coatings
deposited via plasma assisted chemical vapor deposition that deter
protein adsorption--see, for example, Erika E. Johnston E. E.,
Bryers J. D., Ratner B. D. Langmuir 2005, 21, 870-881; Sardella E.,
Gristina R., Senesi G. S., d'Agostino R., Favia P. Plasma Process.
Polym. 2004, 1, 63-72; Shen M., Martinson L., Wagner M. S., Castner
D. G., Ratner B. D., Horbett T. A. J. Biomater. Sci. Polymer Edn.
2002, 13, 367-390; Shen M., Pan Y. V., Wagner M. S., Hauch K. D.,
Castner D. G., Ratner B. D., Horbett T. A. J. Biomater. Sci.
Polymer Edn. 2001, 12, 961-978; Ratner B. D., Lopez G. P. U.S. Pat.
No. 5,153,072 1992; Lopez G. P., Ratner B. D. J. Polym. Sci.
A--Polym. Chem. 1992, 30, 2415-2425; Ratner B. D., Lopez G. P. U.S.
Pat. No. 5,002,794 1991. For (derivatized) alkanethiol coatings
deposited that deter protein adsorption see, for example, Li L. Y.,
Chen S. F., Ratner B. D., Jiang S. Y. J. Phys. Chem. B 2005, 104,
2934-2941; Chirakul P., Perez-Luna V. H., Owen H., Lopez G. P.
Langmuir 2002, 18, 4324-4330; Prime K. L., Whitesides G. M. J. Am.
Chem. Soc. 1993, 115, 10714-10721; Pale-Grosdemange C., Simon E.
S., Prime K. L., Whitesides G. M. J. Am. Chem. Soc. 1991, 113,
12-20. For organosilane coatings that deter protein adsorption see,
for example, Seigers C., Biesalski M., Haag R. Chem. Eur. J. 2004,
10, 2831-2838; Sunder A., Mulhaupt R. United States Patent
Application 2003/0092879 2003; Yang 2., Galloway J. A., Yu H.
Langmuir 1999, 15, 8405-8411; Lee S. W., Laibinis P. E.
Biomaterials 1998, 19, 1660-1675; Lee S. W., Laibinis P. E. U.S.
Pat. No. 6,235,340 2001. For hydrogel (H) coatings that deter
protein adsorption see, for example, Mao G., Metzger S. W.,
Lochhead M. J. U.S. Pat. No. 6,849,028 2005. For
poly-L-Iysine/polyethylene glycol coatings that deter protein
adsorption see, for example, Hubbel J. A., Textor M., Elbert D. L.,
Finken S., Hofer R., Spencer N. D., Ruiz-Taylor L. United States
Patent Application 2002/0128234 2002; Huang N. P., Michel R., Voros
J., Textor M., Hofer R., Rossi A., Elbert D. L., Hubbell J. A.,
Spencer N. D. Langmuir 2001, 17, 489-498; Kenausis G. L. Voros J.,
Elbert D. L., Huang N., Hofer R., Ruiz-Taylor L., Textor M.,
Hubbell J. A., Spencer N. D. J. Phys. Chem. B 2000, 104, 3298-3309.
For polyethylene oxide graft coatings see, for example, Sofia S.
J., Premnath, V., Merrill E. W. Macromolecules 1998, 31, 5059-5070.
These examples represent but are not an exhaustive compilation of
the large number of available surface treatment and/or coating
possibilities.
[0006] Currently, no commercially available pharmaceutical package
(native or coated) contains all of the favorable characteristics
described above, but tends to have a few desirable ones while still
having some that promote protein adsorption. While glass
(borosilicate, soda-lime, etc.) is hydrophilic and hydrogen bond
accepting, it is highly ionic and has no steric hindrance to deter
protein binding. The high density of negative charges under liquid
formulation conditions (pH 5-9) on the surface will promote the
ionic binding of positively charged residues on the proteins (i.e.
lysine, histidine, and the amino terminus). The siliconization of
glass to passivate the surface and provide lubricity in syringes
results in a relatively non-ionic surface that is sterically
blocked, but the silicone oil renders the surface very hydrophobic
while decreasing its hydrogen bond accepting ability. Hydrophobic
surfaces tend to exclude water and facilitate the adsorption of
proteins. The hydrophobicity of the environment the proteins
encounter can also lead to protein denaturation as the hydrophobic
core of the proteins seeks to interact with the surface and unfold
it's native structure to obtain a minimum free energy conformation.
Hydrophobic coatings containing fluorine with anti-adherency
properties for solutions/suspensions containing medicinally
relevant particles/agglomerates have been prepared previously by
plasma enhanced chemical vapor deposition--see, for example,
Walther M., Geiger A., Auchter-Krummel P., Spalleck M. U.S. Pat.
No. 6,599,594 2003.
[0007] Therefore, glass and polymeric surfaces would certainly
benefit from a coating that would contain all of the desirable
characteristics and would deter macromolecule and in particular
protein binding. Surfaces susceptible to macromolecule (e.g.,
protein) adsorption include pharmaceutical packaging components
(e.g., glass vials, ampoules, stoppers, caps, ready to fill glass
and plastic syringes, cartridge-based syringes, pure
silica-surfaced vials, plastic-coated glass vials, plastic and
glass storage bottles, pouches, pumps, sprayers and pharmaceutical
containers of all types) and medical devices (e.g., catheters,
stents, implants, syringes etc). Any candidate surface considered
for contact with a protein and is susceptible to protein adsorption
can be coated to reduce the amount of bound protein. Many polymer
coatings have been designed with the theoretical considerations
described above in mind, but there has not been a solution to the
problem for pharmaceutical packages and the rigors that must be met
for the coating to be utilized along with protein drugs. The
results obtained on gold coated substrates (Ostuni E., Yan L.,
Whitesides G. M. Colloids Surfaces B: Biointerfaces 1999, 15, 3-30)
with self-assembled monolayer coatings elucidating the
characteristics that make a coating effective at reducing protein
adsorption (Pertsin A. J., Grunze M., Garbuzova I. A. J. Phys.
Chem. B 1998, 102, 4918-4926; Seigel R. R., Harder P., Dahint R.,
Grunze M., Josse F., Mrksich M., Whitesides G. M. Anal. Chem. 1997,
69, 3321-3328) have little practical application to the realities
of pharmaceutical packages due to cost of such a surface. The
real-life applications are with pharmaceutically relevant surfaces
that are coated (e.g. glass, rubber, elastomers, plastics, and
other polymers) and then tested exposed/filled with proteins that
are possible drug candidates or already established drugs (e.g.,
immunoglobulins, insulin, erythropoietin, etc.).
[0008] FIGS. 1a, 1b, 1c, and 2 depict methods of the present
invention. To produce coatings acceptable under the national
regulatory agency regulations (FDA, USP, EP, JP) there is the
requirement to manufacture coatings that can be 100% verifiable for
quality--current methods of plasma assisted chemical vapor
deposition coating via batch reactors cannot yet achieve the
coating reproducibility required in a cost effective manner nor can
they be verified in a cost effective manner. Barrier coatings, such
as SiO.sub.2, to reduce ion exchange between substrate and solution
and to reduce the exposure of packaged solutions to various gases,
have been successfully applied to the standards required by
pharmaceutical packaging governing agencies via plasma enhanced
chemical vapor deposition methods--see for example (DE 196 29 877
M. Walther et al.; EP 08 210 79 M. Walther et al.; DE 44 38 359 M.
Walther et al.; EP 07 094 85 M. Walther et al.; DE 296 09 958 M.
Walther et al.). U.S. Pat. No. 6,599,594 discloses coatings
comprising Si, O, C, and H; coatings comprising Si, O, C, H, F;
HMDSO (hexamethyldisiloxane) coatings;
C.sub.6F.sub.10(CF.sub.3).sub.2 coatings; and C.sub.6F.sub.6
coatings. These coatings are known from the literature to slightly
reduce the adsorption of certain proteins but not to fully deter
protein adsorption or prevent protein denaturation. See, for
instance, Fang F., Szleifer I. Biophys J 2001 80 2568-2589
(adsorption of albumin and IgG from serum). U.S. Pat. No. 5,900,285
discloses HMDSO (containing Si, C, H, O); polyethylene, parylene,
polybutene, polypropylene, polystyrene (containing C, H);
phthalocyanine (containing C, H, N), and various, mainly
hydrocarbon containing, molecules for use as barrier coatings.
While the barrier coatings act to protect the formulations inside
of a pharmaceutical package against diffusing species such as water
vapor, carbon dioxide, oxygen, etc. and from ion exchange with the
packaging material, they are generally not effective at deterring
protein adsorption or preventing protein denaturation.
[0009] However, coating precursors, specifically organic (ethers,
esters) precursors that reduce protein adsorption having the
aforementioned properties when used as a coating deposited via
plasma assisted chemical vapor deposition, have not been
successfully applied to pharmaceutical packages due to the
technical issues (precursor chemical and temperature stability, low
power deposition, reproducibility of coating properties, uniformity
of coatings, etc.) associated with their deposition.
SUMMARY OF THE INVENTION
[0010] The present invention relates to a method of preparing a
macromolecule deterrent surface on a pharmaceutical package (or
synonymously, a pharmaceutical container) by depositing a coating
that deters macromolecule adsorption directly onto the surface of a
pharmaceutical package by plasma chemical vapor deposition. The
pharmaceutical package acts as the reaction chamber thus creating a
uniform coating. Various pharmaceutical packages and components
thereof such as vials, plastic-coated vials, syringes, plastic
coated syringes, ampoules, plastic coated ampoules, cartridges,
bottles, plastic coated bottles, pouches, pumps, sprayers,
stoppers, plungers, caps, stents, lids, needles, catheters or
implants can be coated according to the method of the present
invention, Any pharmaceutical package that comes in contact with a
pharmaceutical or biotechnological substance or formulation is
contemplated. Pharmaceutical packaging substrates made from glass
(e.g., Type 1, a silicate, a borate, a borosilicate, a phosphate, a
soda-lime silicate, Type 2, Type 3, and colored versions thereof to
protect formulations from various forms of electromagnetic
radiation), chemically treated glass (e.g., to decrease surface and
near surface alkali content or to increase the strength of the
glass), acrylic, polycarbonate, polyester, polypropylene,
polyacetal, polystyrene, polyamide, polyacrylamide, polyimide,
polyolefin, cyclic olefin copolymers (e.g. Topas.TM.--COC), rubber,
elastomers, a thermosetting polymer, a thermoplastic polymer,
metals, or alloys are contemplated. In particular, pharmaceutical
packaging materials that have a siliconized or silanized surface
are useful as are pharmaceutical packaging materials that have a
coating which lowers the surface energy by .gtoreq.5 dynes/cm
relative to the uncoated pharmaceutical package (e.g. silicone oils
and hydrophobic coatings that aid in emptying out the container).
Also useful are pharmaceutical packaging materials that have a
barrier coating to reduce ion exchange, leachables, extractables,
oxygen permeation, oxygen migration, water migration, water
permeation, carbon dioxide permeation, and electromagnetic
radiation transmission.
[0011] In comparison to uncoated pharmaceutical package substrates
the substrates prepared by the method of the invention reduce the
adsorption of macromolecules to the surface by more than 25%.
Preferred coatings reduce the adsorption of macromolecules to the
surface by more than 50% and particularly preferred coatings reduce
the adsorption of macromolecules to the surface by more than 75%.
Macromolecules that are deterred include naturally occurring or
synthetically prepared biomolecules or a derivative thereof (e.g.,
nucleic acid, polynucleotide, protein, carbohydrate, or
protein/nucleic acid complex) in solution or solid state.
[0012] The coating precursors can be from any chemical family.
Preferred families are ethers, esters, silanes, oxides, and
functionalized derivatives thereof. Most preferably the coatings of
use in the present invention may be prepared from one or more
chemical precursors such as, for example, an ether monomer or ester
monomer or functionalized derivatives thereof, which contains one
or more halogen, alkyl, vinyl, alkynyl, aromatic, hydroxylic, acid,
carbonyl, aldehyde, ketone, amine, amino, amide, nitro or sulfonyl
derivatized functional groups. Particularly preferred coating
precursors are polyethers (e.g., diglyme, a triglyme, a tetraglyme,
a pentaglyme, a hexaglyme, or functionalized derivatives thereof).
Excellent reduction in macromolecule adsorption to pharmaceutical
packages can be achieved with tetraethylene glycol dimethyl ether
(TG). Suitable precursors may be deposited either simultaneously or
in sequence. Additionally they may be applied over an existing
coating such as a first inorganic oxide layer (e.g., SiO.sub.2,
TiO.sub.2, ZrO.sub.2 or Al.sub.2O.sub.3), a first adhesion layer,
or a barrier layer. Suitable precursors are the compounds disclosed
in DE 196 29 877; EP 08 210 79; DE 44 38 359; EP 07 094 85 and DE
296 09 958, which are incorporated by reference herein.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0013] Various features and attendant advantages of the present
invention will be more fully appreciated as the same becomes better
understood when considered in conjunction with the accompanying
drawings, in which like reference characters designate the same or
similar parts throughout the several views, and wherein:
[0014] FIG. 1a: Schematic diagram of a preferred plasma assisted
chemical vapor deposition system using the pharmaceutical article
(vial or syringe) as the coating chamber.
[0015] FIG. 1b: Schematic diagram of one preferred plasma assisted
chemical vapor deposition system using a double chamber reactor
whereby the pharmaceutical article (vial or syringe) is used as a
coating chamber. High frequency energy (preferably microwave energy
with 2.45 GHz) is split into two parts and coupled into the
reaction chamber by separate antennas.
[0016] FIG. 1c: Schematic diagram of one preferred plasma assisted
chemical vapor deposition system using a double chamber reactor
whereby the pharmaceutical article (vial or syringe) is used as a
coating chamber. High frequency energy (preferably radio frequency
energy with 13.56 MHz is coupled into the two reaction chambers
using separate outer and inner electrodes for each chamber. The gas
lances are used as inner electrodes.
[0017] FIG. 2: Schematic diagram of a plasma assisted chemical
vapor deposition system with multiple stations for coating multiple
individual articles simultaneously.
[0018] FIG. 3: The effect of changing the surface charge to affect
the binding of positively and negatively charged proteins {histone,
lysozyme (positive) and human serum albumin (HSA-negative)}. The
proteins are labeled with a fluorescent dye (Cyanine-3) and then
incubated on uncoated and aminosilanized Type 1 formulated glass
slide surfaces. The signal is a direct indication of the amount of
protein adsorbed to the surface.
[0019] FIG. 4: Reduction of protein adsorption on uncoated and
various coated Type 1 formulated glass slides. The table describes
the results with respect to the Fiolax control. The "% decrease vs.
Fiolax" refers to the % less of protein adsorption observed with
respect to Fiolax. The column marked "#>50% Adsorp. Decrease Met
vs Fiolax" refers to the % of time that the reduction in protein
adsorption is reduced by at least 50% with respect to Fiolax. This
is a percentage of 15 samples (5 proteins in three different
formulations).
[0020] FIG. 5: Description of method used to analyze the adsorption
of proteins to pharmaceutical packaging (PP) surface. The method is
based on removing the protein that is adsorbed to the surface by
washing with 50 mM NaOH/0.5% SDS. This solution removes more than
90% of the protein adsorbed onto glass slides.
[0021] FIG. 6: Adsorption of insulin to coated tetraglyme (TG) and
poly-1-lysine/polyethylene glycol (SS) and uncoated vials (Fiolax).
The vials are incubated with the protein solution and the
adsorption is determined using the method described in Example
1.
[0022] FIG. 7: Adsorption of insulin to hydrogel (H) coated
syringes. Glass and Topas.TM. polymer syringes (COC copolymer made
from norbornene and ethylene) are coated with the H coating and the
amount of protein adsorbed is measured using the method described
in Example 1.
[0023] FIG. 8: Comparison of the adsorption of fluorescently
labeled fibrinogen, IgG, insulin, histone, and carbonic anhydrase
at pH 5, 7, 9 for H and TG coated surfaces.
[0024] FIG. 9: Comparison of the coefficient of variation of
fluorescently labeled fibrinogen, IgG, insulin, histone, and
carbonic anhydrase at pH 5, 7, 9 for H and TG coated surfaces.
[0025] FIG. 10: Table of % C/O from deconvoluted photoelectron C1s
spectra from two batch processes and three individual coatings
using the article as the reactor showing the higher % contribution
of C/O and reduced variation using the article as the reactor.
[0026] FIG. 11: Compares protein (histone and insulin) adsorption
onto vials having various surfaces. As can be seen compared to the
Type 1+surface (Type 1 glass with barrier coating), TG reduces the
adsorption of protein by 90%.
[0027] FIG. 12. Depicts the activity of alkaline phosphatase after
adsorption to different coated Type 1 glass slides.
[0028] FIG. 13. Compares fibrinogen adsorption on slides coated
with tetraglyme deposited via a plasma-assisted process vs. slides
coated with tetraglyme deposited via dip-coating or chemical vapor
deposition methods.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The term "pharmaceutical package" as used herein means any
container or medical device or component(s) thereof that comes in
contact with a pharmaceutical, biological or biotechnological
substance or formulation in solution or solid state. Examples
include vials, plastic-coated vials, syringes, plastic coated
syringes, ampoules, plastic coated ampoules, cartridges, bottles,
plastic coated bottles, pouches, pumps, sprayers, stoppers,
plungers, caps, lids, needles, catheters, stents, implants, and
components thereof which come in contact with macromolecules.
[0030] The term "macromolecule" as used herein means naturally
occurring or synthetically prepared biomolecules or derivatives
thereof such as, for example, nucleic acids, polynucleotides,
proteins, peptides, antibodies, carbohydrates, protein/nucleic acid
complexes, in solution or solid state.
[0031] The term "protein solution" refers to a particular protein
of interest in the presence of (typically) an aqueous solution that
may contain various additives, which can also have an effect on the
adsorption of the proteins to the surface. Typical protein
solutions to be tested include pharmaceutically relevant moieties
such as cells, tissues, and derivatives thereof. Among the proteins
are included any polyaminoacid chain, peptides, protein fragments
and different types of proteins (e.g., structural, membrane,
enzymes, antigens, monoclonal antibodies; polyclonal antibodies,
ligands, receptors) produced naturally or recombinantly, as well as
the derivatives of these compounds, etc. Specific protein drugs
include antibodies (e.g. Remicade and ReoPro from Centocor;
Herceptin from Genentech; Mylotarg from Wyeth, Synagis from
MedImmune), enzymes (e.g. Pulmozyme from Genentech; Cerezyme from
Genzyme), recombinant hormones (e.g., Protropin from Genentech,
Novolin from Zymogenetics, Humulin from Lilly), recombinant
interferon (e.g., Actimmune from InterMune Pharmaceutical; Avonex
from BiogenIdec, Betaseron from Chiron; Infergen from Amgen; Intron
A from Schering-Plough; Roferon from Hoffman-La Roche), recombinant
blood clotting cascade factors (e.g., TNKase from Genentech;
Retavase from Centocor; Refacto from Genetics Institute; Kogenate
from Bayer) and recombinant erythropoietin (e.g., Epogen from
Amgen; Procrit from J&J), and vaccines (e.g., Engerix-B from
GSK; Recombivax HB from Merck & Co.).
[0032] The term "plasma chemical vapor deposition" as used herein
encompasses assisted, enhanced, impulse or continuous chemical
vapor deposition and variations thereof (in the literature assisted
and enhanced are sometimes used interchangeably). Assisted plasma
CVD means the desired coating requires plasma to achieve the
required properties or processing considerations with respect to
its CVD produced counterpart. A coating can be deposited via CVD
but the coating process (rate, uniformity, thickness, etc.) and or
properties (morphology, macromolecule deterrence, etc.) are
enhanced using plasma. Plasmas are useful in coating processes when
generation of charged reactive species and their transport to
substrates for participation in the coating formation are important
parameters. En impulse plasma CVD the energy is supplied in a
non-continuous fashion whereas in continuous plasma CVD the energy
is continuous.
[0033] As used herein the term "reaction chamber" means the
pharmaceutical package, as discussed above, acts, as the coating
chamber. The precursor gas is applied directly into the
pharmaceutical container and electromagnetic radiation is applied
generating a plasma. The resulting reaction creates a coating on
the surface of the pharmaceutical package that will come in contact
with macromolecules. For example, see FIGS. 1a-1c and 2.
[0034] This invention pertains to an improved method of manufacture
and deposition of coatings to deter macromolecule (e.g. protein)
adsorption to pharmaceutical packaging materials by plasma chemical
vapor deposition. The current state of the art for depositing
coatings that reduce protein adsorption via plasma assisted
chemical vapor deposition is described for radio-frequency power
sources using barrel type (Ratner B. D. et al. U.S. Pat. No.
5,002,794; Ratner B. D. et al. U.S. Pat. No. 5,153,072) and
parallel plate (Sardella E. et al Plasma Process. Polym. 2004, 1,
63-72) designs. These reactors enable small batch production with
limited substrate size and control over coating uniformity.
For'application in the pharmaceutical packaging industry, products
have to be produced with processes that are highly controlled and
verifiably reproducible; pharmaceutical packaging products are
typically required by the respective national pharmacopeias
(USP/EP/JP) and/or pharmaceutical manufacturers to go through 100%
quality control of the packaging container production process. The
current designs and resulting process coating methodology need to
be improved to reproducibly manufacture coated articles to these
standards while enabling higher volume production of a variety of
substrate dimensions.
[0035] This invention is a fundamental change in reactor design and
process methodology to the current state of the art. The invention
utilizes the pharmaceutical package and/or component(s) thereof
(e.g. vial, syringe, ampoule, bottle, piston, needle, cap etc.) as
the reaction chamber. By using the substrate as the reaction
chamber a higher degree of control over the applied coating can be
achieved compared to a batch type process in which a larger
reaction chamber is utilized. Systems of these types have been
successfully built and used in the food and pharmaceutical
industries to deposit SiO.sub.2 barrier coatings (oxygen barriers).
A pictorial description of a preferred embodiment is shown in FIGS.
1a-1c. The pharmaceutical package (and/or components thereof) is
brought into contact with a structure (in one preferred embodiment
the structure is a flat-bottom U-shaped structure; see FIG. 1a).
The package is sealed to the flat-bottom U-shaped structure and
sealed via a vacuum pump system. In a first step the package is
evacuated only inside by a vacuum pump. In a next step, after
opening valves, the process gas containing the precursor(s) flows
through a gas channel (e.g. a gas lance) into the chamber and it is
pumped continuously by a vacuum pump. High frequency energy (e.g.
radio frequency, microwave frequency with pulsed energy) is coupled
into the package and used to ignite plasma inside the container.
During the plasma coating process the light emission of the plasma
and other process parameters like pressure, gas flow, and
temperature are monitored. After depositing the coating layer onto
the internal container surface the connection to the vacuum pump
and to the gas source is interrupted by valves and the input of
high frequency energy is stopped. The package is vented to
atmospheric pressure and leaves the structure afterwards. A
preferred method includes one or more additional steps prior to the
process gas being introduced. These additional steps include the
introduction of a carrier gas (i.e. argon, nitrogen, oxygen,
helium, neon, etc.) to the chamber and ignition of a plasma for
surface chemistry modification, removal of contaminants (i.e.
adventitious carbon), sterilization, and/or heating of the chamber.
In a preferred embodiment multiple stations are used to coat
multiple individual articles simultaneously (FIG. 3).
[0036] There are several improvements obtained using the substrate
as the reaction chamber over batch type reactors. Process times can
be shortened due to smaller area to be coated (one substrate vs.
many) and lower volumes of precursors are required. Coating
uniformity is improved by having a stable, reproducible plasma
field over the coating area. The plasma field required for one
substrate is smaller (i.e. easier to make, more uniform and stable)
and more cost effective to generate than a plasma field required
for a larger area that coats many substrates simultaneously. Good
coating uniformities can especially be realized on 3-dimensional
substrates by using a pulsed plasma process leading to a good gas
exchange during the interruption of the plasma ignition. 100%
verification of coating deposition is easier and more cost
effective to achieve using the substrate as the reaction chamber
compared to substrates prepared in a plasma assisted chemical vapor
deposition batch process. For this 100% quality inspection the
light emission of the plasma, the process pressure, the coating
temperature and gas flow can be controlled and verified for each
coated container. Furthermore, another important advantage of using
the pharmaceutical package as a coating reactor is that no
contamination of the surface occurs whereas contamination from
particulates occurs in many batch reactors. Thus, the method of the
present invention avoids the problem of particles falling into the
package and maintenance work for cleaning the reactor chamber is
eliminated. An additional advantage of this method is the use of a
positive temperature gradient, which helps to limit and/or avoid
condensation of the coating onto the article surface.
[0037] This method is applicable to all electromagnetic energy
sources. Preferred frequencies are high frequencies, mainly 40 kHz,
13.56 MHz, 2.45 GHz. This method is applicable to all
pharmaceutical packaging components (e.g., vials, syringes,
ampoules, plungers, stoppers, needles, gaskets etc.) and their
materials (e.g., glass, elastomer, polymer, metal, alloys, etc.).
The pharmaceutical package material can be any glass, polymer,
copolymer, metal, or alloy. Preferred materials are borosilicate
(FIOLAX.TM., SUPRAX.TM., and DURAN.TM.) and soda lime glasses,
Topas COC.TM. resins (cyclic olefin copolymer made from ethylene
and norborene), iron/titanium/aluminum and alloys thereof, rubber,
silicone, and silanized or siliconized coated materials thereof.
Exemplary borosilicate glass compositions are disclosed in W.
Kiefer U.S. Pat. No. 4,870,034 1989 and E. Watzke et al U.S. Pat.
No. 5,599,753 1997. Another form of preferred materials are
thermoplastic polymer coated versions of the aforementioned
container materials (PURGARD.TM.).
[0038] The coating precursors may be from any chemical family.
Preferably, the coating will be universal, and as such deter the
adsorption of all potential proteins formulations. In some
instances, this will not be the case and an initial analysis of
some of the proteins properties {e.g., pI, charged residues,
modifications (glycosilations), hydrophobicity/hydrophilicity}
could lead to specific characteristics to be included in the
coating formulation. Analysis of the surface (e.g., energy,
roughness, charge, and functional groups) of various packaging
components could also lead to specific characteristics and/or
modifications of the coating formulation to reduce the adsorption
of the protein. With this in mind, preferred coating families are
glycols, ethers, esters, alcohols, methacrylates, silanes and
derivatized members thereof. Especially preferred coating
precursors for use in the present invention include compounds
containing carbon-oxygen bonding. Particularly preferred coating
precursors include compounds having the elements C, H and O;
polyethylene glycols, glycol ethers, commonly known as glymes
(e.g., monoglyme, ethyl glyme, diglyme, ethyl diglyme, triglyme,
butyl diglyme, tetraglyme, pentaglyme, hexaglyme and their
respective corresponding monoalkyl ethers) and functionalized
derivatives such as, for example, polyethylene glycol with an end
functionalized silane. Coatings applied by this method may be
deposited over pre-existing coatings such as barrier coatings
(e.g., oxides such as SiO.sub.2) and silicone formulations sprayed
or dipped and baked on surfaces (i.e. used to provide lubricity for
syringes).
[0039] Although this application is written preferably in terms of
proteins, it can also be applied to other macromolecules or
biomolecules such as nucleic acids, peptides, antibodies,
polynucleotides (e.g., DNA, RNA, pDNA, etc., oligonucleotides),
protein/nucleic acid complexes (e.g., viral particles for gene
therapy) in a liquid ("solution") or solid state ("lyophilized"),
etc. by straightforward extension. Certain approaches to the
methods of the present invention are preferred. For example, the
coating may be applied with pulsed electromagnetic radiation,
preferably with low or high frequency energy of 40-100 kHz, 13.56
MHz or 2.45 GHz. The coating may be deposited onto the surface of a
pharmaceutical package by plasma chemical vapor deposition (CVD),
wherein said coating is prepared from a mixture of one or more
chemical precursors and an additional carrier gas, such as, an
inert gas. Preferable gases include Argon, Helium, Neon, Xenon,
Krypton or Nitrogen. The precursor concentration, defined as the
ratio total precursor flow/(total carrier gas flow+total precursor
flow), is generally between 5% and 95%, preferably between 10% and
90%, and most preferably between 30% and 50%. Pre-conditioning of
the substrate by a heat or plasma treatment process before
deposition of the coating is desirable. If the substrate
temperature is nearly equal to the temperature of the process gas
introduced into the reaction chamber, condensation of the process
gas on the substrate before, during and after the coating process
can be avoided. Thus, it is preferred that the coating is deposited
while maintaining an equal or positive temperature difference
between the substrate and other parts of the coating system.
Typically, the coating is deposited by using an average power
density, defined by the ratio average power/plasma volume, between
0.05 W/cm.sup.3 and 50 W/cm.sup.3. Preferably, the power density is
between 0.08 W/cm.sup.3 and 10 W/cm.sup.3 and most preferably
between 0.1 W/cm.sup.3 and 5 W/cm.sup.3. The coated substrate
surfaces may be defined by a fibrinogen adsorption of the coated
substrate that is less than 500 ng/cm.sup.2, preferably less than
200 ng/cm.sup.2 and most preferably less than 150 ng/cm.sup.2 (for
a .ltoreq.10 .mu.g/ml fibrinogen solution over a incubation period
of 72 hours). Coating time may vary depending on the pharmaceutical
packaging. Generally, the functional coating that deters
macromolecule adsorption onto the surface of a pharmaceutical is
deposited in 10 minutes or less, preferably 3 minutes or less, and
most preferably 1 minute or less. Coating thickness may also vary.
Generally, the functional coating that deters macromolecule
adsorption onto the surface of a pharmaceutical package has a
coating layer thickness between 0.3 nm and 500 nm, preferably
between 0.5 nm and 200 nm, most preferably between 1 nm and 50
nm.
[0040] Without further elaboration, it is believed that one skilled
in the art can, using the preceding description, utilize the
present invention to its fullest extent. The preceding preferred
specific embodiments are, therefore, to be construed as merely
illustrative, and not limitative of the remainder of the disclosure
in any way whatsoever. The entire disclosure[s] of all patent
applications, patents, and papers cited herein are incorporated by
reference herein.
Examples
1) Testing of Generally Accepted Principles for Coatings that
Reduce Binding of Proteins
Deterring Binding of Positively Charged Proteins.
[0041] Proteins such as histone and lysozyme are positively charged
at physiological pH (around 7.4) and it is postulated that a
positively charged surface should reject the regions of the
proteins abundant in positive charges resulting in an overall
decrease in the amount of protein adsorbed. Fluorescently labeled
histone, human serum albumen, and lysozyme are incubated on a
surface that has been coated with an aminosilane (C. G. Panto, E.
Metwalli, S. Conzone, D. Haines U.S. Pat. No. 6,916,541 B2). The
proteins are incubated at different pH values. A control of bovine
serum albumin (BSA) is also included. This protein has an acidic pI
(5.2) and would be mostly negatively charged at the pH values
tested.
[0042] The results shown in FIG. 3 demonstrate the effect of the
positively charged surface, where the positively charged proteins
(i.e., histone and lysozyme) show a 2-4-fold decrease in adsorption
when compared to uncoated glass slides that will have a net
negative charge {pI of the aminosilane is around pH 9 (E. Metwalli,
D. Haines, O. Becker, S. Conzone, C. Pantano J. Colloid Interfac.
Sci. 2006, 298, 825-831; U. Jonas, A. del Campo, C. Kruger, G.
Glasser, D. Boos PNAS 2002, 99, 5034-5039}. The behavior of BSA
also agrees with the theoretical considerations of ionic attraction
of the negatively charged protein to the amino-coated surface,
resulting in an increase in the adsorption to the surface.
2) Testing of Generally Accepted Principles for Coatings that
Reduce Binding of Proteins
Deterring Protein Adsorption by Various Coatings.
[0043] A matrix of proteins and formulations is used to test
various coated surfaces. These tests are done on a multiplexed
slide (coated and uncoated glass and COC polymer materials) format
as disclosed in U.S. Patent Application 60/617,192 titled
"Multiplexed protein adsorption assay" where a coated surface is
exposed to multiple proteins under different conditions
simultaneously. After incubation, the absorbance of proteins to the
surface is compared under different conditions, proteins and for
different surfaces. The results are then confirmed in the final
pharmaceutical package coated with the different coatings.
[0044] Fluorescently labeled fibrinogen, insulin, histone,
immunoglobulins gamma, and carbonic anhydrase are formulated in 100
mM phosphate at three different pH values (5, 7, and 9). The
protein solutions are incubated in different wells on coated and
uncoated borosilicate glass slides for a period of 3 days. After
the incubation period, the wells are washed and the slides are
scanned using a laser fluorimeter to quantify the amount of protein
adsorbed. The results are compared to the amounts of protein
adsorbed to an uncoated Fiolax control slide (a borosilicate Type 1
glass Schott uses to make pharmaceutical packages).
[0045] The results in FIG. 4 describe the average reduction in
protein adsorption for all the proteins tested when comparing the
performance on the coated slide surface to the control slide
surface.
[0046] Also indicated is the frequency with which the coatings
produced a reduction of at least 50% protein adsorption. Each
coating is tested .gtoreq.five times with three repeats on each
occasion. The coatings and surfaces utilized to obtain the data in
FIG. 5 are described below: [0047] 1. Fiolax: Glass slide made of
type 1 glass composition produced by SCHOTT Form a Vitrum. [0048]
2. TG: Tetraglyme (tetraethylene glycol dimethyl ether) coating
applied by radio-frequency plasma assisted chemical vapor
deposition methods in a batch reactor process. Samples are
purchased from the University of Washington Bioengineered Materials
Consortium. Coatings are applied as per disclosed in U.S. Pat. No.
5,002,794 and U.S. Pat. No. 5,153,072. [0049] 3. H: A formulation
based on an aminosilane and a PEG polymer capped with one NHS-ester
applied via spin-coating. The coated slides are purchased from and
produced by Accelr8 Corporation according to previously disclosed
methods G. Mao, S. W. Metzger, M. J. Lochhead U.S. Pat. No.
6,844,028. [0050] 4. SS: A formulation prepared by first depositing
poly-L-Lysine onto the surface and then modifying this polymeric
surface with PEG groups applied via dip-coating. The binding of the
coating is through electrostatic interaction. The coated slides and
vials are purchased from and produced by Surface Solutions, GmbH.
Zurich, Switzerland. [0051] 5. AMC: A multilayer coating combining
a metal oxide with fluorinated moieties. The slide coatings
(AMC148-18) are provided as free samples, produced by Advanced
Materials Components Express LLC (Lamont, Pa.). [0052] 6. TBF: a
perfluoropolyether coating purchased from and produced by Tribofilm
Research, Inc. (Raleigh, N.C.) according to the previously
disclosed method (V. G. Sakhrani, J. L. Williams, C. Tomasino, P.
M. Vernon Jr.--United States Patent Application 2004/0231926).
[0053] The results demonstrate that coatings having one or more
protein deterring characteristics (non-ionic, sterically shielding,
hydrophilic, hydrogen bond accepting, not hydrogen bond donating)
reduce the adsorption of proteins to different extents. Coatings
with all the protein deterring characteristics demonstrate the
highest reduction of protein adsorption, with the tetraglyme
producing the largest reduction within the set of protein
tested.
3) Protein Adsorption in Pharmaceutical Packaging
[0054] To corroborate the slide based results shown in FIG. 4, a
method is developed to quantify the amount of protein adsorbed to
the surface of pharmaceutical packaging. The method described in
FIG. 5 relies on the removal of the adsorbed protein. Briefly, the
fluorescently labeled protein solution is incubated in the
pharmaceutical package (PP) for 3 days. The excess is removed and
the PP is washed with water for injection three times. The PP is
then incubated with 50 mM NaOH supplemented with 0.5% SDS for a
period of one hour to remove the adsorbed protein from the surface.
After incubation an aliquot is removed and allowed to dry in a well
of a multiplexed slide. The wells are then scanned and the
fluorescent signal is used to calculate the amount of protein
adsorbed. These results can be extrapolated to determine how much
total protein is adsorbed.
a) TG and SS coated vials. Fiolax vials are coated with TG (from a
batch process) and SS and the adsorption of insulin in these PP is
compared to those in Fiolax glass vials (control). The results in
FIG. 6 have been normalized to Fiolax and demonstrate that the
results seen in the slide assays (FIG. 4) correlate with those seen
in PP assays. The tetraglyme coating reduces the adsorption of
insulin in a PP by >90% while the SS coating reduces the
adsorption by approximately 80%. b) H coated syringes. Syringes are
coated with the H coating solution and tested for the adsorption of
insulin. In this case the coating is applied to both glass and
polymer (a COC copolymer) syringes and the adsorption is compared
to uncoated polymer syringes. The method utilized is the same as
that described above and shown in FIG. 5. The results shown in FIG.
7 demonstrate that there is a reduction of protein adsorption of
around 90% in the coated syringes when compared to the uncoated
control.
4) Variation in Radio-Frequency Plasma Assisted Chemical Vapor
Deposition Tetraglyme Coating Uniformity
[0055] Using the method described in Example 2, hydrogel coated
slides prepared by spin-coating and tetraglyme coated slides
prepared in a batch process by radio-frequency plasma assisted
chemical vapor deposition are compared for protein adsorption and
coating uniformity. FIG. 8 shows the relative protein adsorption
for hydrogel and tetraglyme coatings--tetraglyme coated substrates
adsorb less proteins in all 4 tests that had statistical
differences between the two coatings. FIG. 9 shows the high
variability of the tetraglyme coating macromolecule absorption
deterring uniformity compared to the hydrogel coating--coefficient
of variation is obtained by dividing the standard deviation by the
signal intensity.
5) Deposition of Protein Deterrent Coating Wherein Container Acts
as Reaction Chamber
[0056] Two Fiolax vials (10 ml total volume) are put into a double
chamber reactor and are simultaneously evacuated to a basic
pressure below 0.1 mbar. After evacuation of the vials argon flows
into the reactor with mass flow rates of 50 seem at a pressure of
0.2 mbar. The total mass flow is divided into two separate mass
flows being nearly the same for each vial. The energy of a pulsed
microwave source with a microwave frequency of 2.45 GHz and an
average power of 500 Watts is split and coupled into the two
separate chambers. A pulsed microwave plasma is ignited inside the
two vials and the container is pretreated by the plasma and heated
up to a process temperature of 120.degree. C. During a gas exchange
time a mixture of tetraethyleneglycoldimethylether gas
("tetraglyme") and argon carrier gas with a tetraglyme
concentration of 35% flows into the reactor at a pressure of 0.2
mbar and distributed into the two chambers. The energy of a pulsed
microwave source with a frequency of 2.45 GHz and an average power
of 5.2 Watts is split and coupled into the two separate chambers. A
pulsed microwave plasma is ignited inside the two vials for a
duration of 300 seconds and an organic coating with a thickness of
about 50 nm is deposited only onto the inner surfaces of the vials.
Using a carrier gas in addition to the coating precursor gas
reduces or avoids condensation in comparison to a deposition
process with only a coating precursor gas.
[0057] The fibrinogen adsorption of coated vials and uncoated
Fiolax reference vials is tested according to the method presented
in FIG. 5. The vials are incubated with 2 ml fibrinogen solution
with a fibrinogen concentration of 5 .mu.g/ml containing a
phosphate buffer solution with pH 7. In comparison to the uncoated
reference samples the amount of adsorbed fibrinogen of the coated
vials is reduced by 76%.
6) Comparing Coatings being Made from Radio-Frequency Plasma
Assisted Chemical Vapor Deposition (Barrel Reactor, Batch Process)
Vs. Microwave Frequency Plasma Assisted Chemical Vapor Deposition
(Article as Reactor, Individual Process)
[0058] Tetraglyme coated vials are prepared by radio-frequency
plasma assisted chemical vapor deposition in a barrel reactor by a
batch process and by microwave frequency plasma assisted chemical
vapor deposition using the vial as the reaction chamber as depicted
in FIGS. 1a-1c and 2, and compared for coating uniformity by
photoelectron spectroscopy. In particular, the C1s high resolution
spectra for batch and individually produced tetraglyme coated vials
are compared, showing the higher control of coating uniformity
possible by using the article as the reactor. FIG. 10 shows, in
tabular form, the carbon/oxygen contribution to the C1s
deconvoluted peak from the batch process of two identical batch
runs vs. three samples using the article as the chamber. These
results clearly indicate higher amounts of the carbon/oxygen
contribution are obtained in a more reproducible fashion from the
article as the reactor method. The higher percent contribution of
the 286.5 peak from the deconvoluted spectrum indicates a higher
percent retention of the tetraglyme monomer from the article as the
reactor method vs. the batch method.
7) Difference in Deterring Protein Adsorption Between Uncoated
Control Glass, SiO.sub.2 Barrier Coatings Produced by Plasma
Impulse Chemical Vapor Deposition, Siliconized Coatings Applied
Over Control Glass and SiO.sub.2 Barrier Coating, and Tetraglyme
Coatings Produced by Plasma Assisted Chemical Vapor Deposition.
[0059] Using the method described in Example 2 and pictorially
shown in FIG. 5 several different coatings are evaluated for their
ability to reduce the binding of histone-cy3 and insulin-cy3 in
vials. The results shown in FIG. 11 demonstrate the following: 1)
control uncoated glass samples strongly adsorb histone-cy3 and
insulin-cy3; 2) SiO.sub.2 barrier coating ("Type 1+") adsorbs
histone-cy3 and fibrinogen-cy3 even more strongly then uncoated
control glass; 3) Topas vials adsorb histone-cy3 and insulin-cy3 to
a slightly greater extent than uncoated control glass; 4)
siliconization of control glass and SiO.sub.2 coating do not reduce
histone-cy3 and insulin-cy3 adsorption relative to non-siliconized
samples; 5) tetraglyme coated vials reduce the adsorption of
histone-cy3 and insulin-cy3 by a factor of 10.
8) Protein Stability Due to Coatings
[0060] The effect of the glass surfaces on proteins can be very
detrimental. The adsorption of proteins through ionic interaction
can lead to protein denaturation and loss of activity. Some
coatings can also more strongly bind proteins (even through
covalent linkages), which can have an immediate effect on the
proteins activity. To demonstrate the importance of the inertness
of the coating, enzymes are deposited on aldehydesilane,
epoxysilane, and H coated Type 1 glass slides and allowed to
immobilize for two hours. After that time the activity of the
enzymes is determined. As can be observed in FIG. 12, the alkaline
phosphatase immobilized onto aldehyde or epoxy coated surfaces have
lost all of their activity, while the enzyme immobilized to the H
coated surface retains almost all of the activity, indicating that
the enzyme is still active.
9) Plasma Deposition Method Necessary for Deterring Protein
Adsorption
[0061] Cyclic olefin copolymer microscope slides are coated with
tetraglyme from a radio frequency plasma assisted chemical vapor
deposition batch process from a barrel reactor system and their
deterrence for fibrinogen binding are compared with Type 1
borosilicate glass microscope slides uncoated and coated with
tetraglyme from both dip-coating and chemical vapor deposition
processes. The objective of this experiment is to determine the
importance of the deposition process on the coating properties. The
samples are evaluated for fibrinogen binding by the method
disclosed in Example 2 using 5 .mu.g/mL fibrinogen in phosphate
buffer at pH 7. The results are shown in FIG. 13. FIG. 13 clearly
demonstrates that tetraglyme coatings are effective at reducing the
adsorption of fibrinogen when deposited via a plasma-assisted
process but not when deposited via dip-coating or chemical vapor
deposition methods.
[0062] The preceding examples can be repeated with similar success
by substituting the generically or specifically described reactants
and/or operating conditions of this invention for those used in the
preceding examples. From the foregoing description, one skilled in
the art can easily ascertain the essential characteristics of this
invention and, without departing from the spirit and scope thereof,
can make various changes and modifications of the invention to
adapt it to various usages and conditions.
* * * * *