(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2008/0226724 A1
`
`
` Ji et al. (43) Pub. Date: Sep. 18, 2008
`
`IJSZOO80226724A1
`
`(54) PREVENTION OF HYDROGEL VISCOSITY
`LOSS
`
`(22)
`
`Filed:
`
`Jan. 22, 2008
`
`(75)
`
`Inventors:
`
`Junyan Andrea Ji, Foster City, CA
`(US) Erika Ingham Berkeley CA
`(US); Yuchang John Wang,
`Burlmgame, CA (US)
`
`(60) Provisional application No. 60/881,260, filed on Jan.
`19’ 2007’
`
`Publication Classification
`
`Related US. Application Data
`
`Correspondence Address:
`QUINE INTELLECTUAL PROPERTY LAW
`GROUP, P.C.
`P 0 BOX 458
`ALAMEDA: CA 94501 (Us)
`
`(51)
`
`Int. Cl.
`(2006.01)
`A61K 9/10
`(2006.01)
`A61K 38/00
`(2006.01)
`B01] 13/00
`(52) us. Cl. ............................ 424/486; 516/106; 514/12
`
`(73) Assignee:
`
`Genentech, Inc., South San
`Francisco, CA (US)
`
`(21) App]. No.:
`
`12/011,027
`
`(57)
`
`ABSTRACT
`
`The present invention comprises methods and compositions
`for decreasing or preventing viscosity loss in hydrogels.
`
`P8961
`
`Teoxane S.A.
`
`Exhibit 102 9
`
`Page 1
`
`

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`Patent Application Publication
`
`Sep. 18, 2008 Sheet 1 0f 9
`
`US 2008/0226724 A1
`
`3500
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`Figure 2A
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`Page 2
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`Page 2
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`

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`Patent Application Publication
`
`Sep. 18, 2008 Sheet 2 0f 9
`
`US 2008/0226724 A1
`
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`
`Page 3
`
`Page 3
`
`

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`Patent Application Publication
`
`Sep. 18, 2008 Sheet 3 0f 9
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`US 2008/0226724 A1
`
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`
`Figure 4
`
`Page 4
`
`Page 4
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`

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`Patent Application Publication
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`Sep. 18, 2008 Sheet 4 0f 9
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`US 2008/0226724 A1
`
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`Page 5
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`Page 5
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`

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`Patent Application Publication
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`Sep. 18, 2008 Sheet 5 0f 9
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`US 2008/0226724 A1
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`Page 6
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`Page 6
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`

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`Patent Application Publication
`
`Sep. 18, 2008 Sheet 6 0f 9
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`US 2008/0226724 A1
`
`120 —
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`
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`Page 7
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`Page 7
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`

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`Patent Application Publication
`
`Sep. 18, 2008 Sheet 7 0f 9
`
`US 2008/0226724 A1
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`
`
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`
`Figure 7C
`
`0.2 mg/ml rhVEGF Methycellose and Hypromellose Gels
`
`
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`
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`
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`
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`
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`
`Figure 8A
`
`Page 8
`
`Page 8
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`

`

`Patent Application Publication
`
`Sep. 18, 2008 Sheet 8 0f 9
`
`US 2008/0226724 A1
`
`1.8 mglml rhVEGF Methycellose and Hypromellose GelsGels
`
`
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`
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`
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`
`Page 9
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`

`

`Patent Application Publication
`
`Sep. 18, 2008 Sheet 9 of 9
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`US 2008/0226724 A1
`
`120 —
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`1
`
`Figure 9B
`
`1.8mg/mL Telbermin Solution Methionine Titration RP-HPLC
`
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`
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`
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`
`Page 10
`
`Page 10
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`

`

`US 2008/0226724 A1
`
`Sep. 18, 2008
`
`PREVENTION OF HYDROGEL VISCOSITY
`LOSS
`
`FIELD OF THE INVENTION
`
`[0001] The current invention relates to the field of hydro-
`gels. More specifically, the present invention provides meth-
`ods for stabilizing hydrogel viscosity, especially for hydro-
`gels that are autoclave sterilized and/or stored for extended
`periods of time, as well as providing compositions of such
`stabilized hydrogels.
`
`BACKGROUND OF THE INVENTION
`
`[0002] Hydrogels of various compositions are widely used
`in myriad applications from paints to pharmaceuticals. For
`example, promising advances in wound treatments utilize a
`number of different types of hydrogels. Hydrogels compris-
`ing cellulose and cellulose derivatives are especially common
`in many applications. However, a drawback to some uses of
`hydrogels, and cellulose based hydrogels in particular, is that
`such gels lose their viscosity under certain conditions. For
`example, many cellulose based hydrogels lose viscosity when
`autoclave sterilized, thus, hampering their use in pharmaceu-
`tical compositions where sterility can be of importance (e.g.,
`when hydrogels are used in contact with an open wound).
`Additionally, storage of hydrogels can allow the reaction of
`hydrogel polymers with free radicals, which can also lead to
`viscosity loss. Such loss is often exacerbated by elevated
`temperatures, and is problematic for hydrogels that need to be
`stored or transported. Prior attempts to prevent or reduce
`hydrogel viscosity loss have been unsuccessful and/or
`impractical.
`[0003] Thus, there is a continuing need for better, more
`economical hydrogel compositions and for methods to ensure
`proper viscosity for hydrogels, especially in regard to hydro-
`gels to be autoclave sterilized and/or those that are to be stored
`for various time periods (e.g., for certain pharmaceutical
`applications). The current invention provides these and other
`benefits which will be apparent upon examination.
`
`SUMMARY OF THE INVENTION
`
`In various aspects herein, the invention comprises
`[0004]
`methods (e. g., pharmaceutical methods) for decreasing or
`preventing viscosity loss (e.g., preserving or stabilizing vis-
`cosity, decreasing loss in viscosity, etc.) in various hydrogel
`formulations. Viscosity loss can arise from reaction between
`free radicals (e. g., hydrogen peroxide) and hydrogel compo-
`nents such as the hydrogel polymers, and/or from autoclaving
`or heating of the hydrogel, as well as from other environmen-
`tal conditions. In various embodiments, the methods com-
`prise providing a hydrogel solution (or mixture, colloid, sus-
`pension, or the like) having one or more metal ion chelators
`and/or one or more radical scavenging moieties. In certain
`embodiments, the hydrogel is autoclave treated (e.g., steril-
`ized) or treatable (e.g., sterilizable). Also in certain embodi-
`ments in which the hydrogel is autoclave treated, the chelator
`(if present in the embodiment) is added to the hydrogel solu-
`tion before the hydrogel is autoclave sterilized, while the
`radical scavenging moiety (if present in the embodiment) is
`added to the solution after the solution is autoclave sterilized.
`
`In other embodiments, the hydrogel is not autoclave treated.
`[0005] The methods herein optionally comprise use of any
`ofa variety ofpolymer molecules capable offorming a hydro-
`gel, such as, but not limited to: polysaccharide molecules,
`
`cellulose molecules, cellulose derivative molecules, methyl-
`cellulose molecules,
`hydroxypropyl methylcellulose
`(hypromellose) molecules, carboxymethyl cellulose mol-
`ecules, hydroxypropyl cellulose molecules, hydroxyethyl
`cellulose molecules, hyaluronic acid molecules, Carbopol®
`molecules (Noveon, Cleveland, Ohio) and their derivatives,
`alginate, sodium hyaluronate, gellan, carrageenan, pectin,
`gelatin, polyvinyl pyrrolidone, poloxamer, dextran, etc. The
`concentration of hydrogels herein can be quantified by per-
`cent polymer molecule to hydrogel solution (weight/vol-
`ume). The concentration of polymer molecule for cellulose/
`cellulose derivatives (e.g., methylcellulose, hydroxypropyl
`methylcellulose, hydroxyethylcellulose, Methocel® A4M,
`grade HEC hydroxyethyl cellulose, or Methocel® E4M) in
`the hydrogels can comprise, e.g., from about 1% to about 6%
`polymer molecule to hydrogel solution, from about 1.25% to
`about 5.5% polymer molecule to hydrogel solution, from
`about 1.5% to about 5.0% polymer molecule to hydrogel
`solution, from about 1.75% to about 4.5% polymer molecule
`to hydrogel solution, from about 2% to about 4% polymer
`molecule to hydrogel solution, from about 2.25% to about 4%
`polymer molecule to hydrogel solution, from about 2.5% to
`about 3.5% polymer molecule to hydrogel solution, or about
`3% polymer molecule to hydrogel solution. It will be under-
`stood, however, that specific recitation of polymer concentra-
`tions in the various hydrogels herein should not necessarily be
`taken as limiting and that the methods (and the compositions)
`herein can also comprise lower or higher concentrations of
`hydrogel polymers in the hydrogels (e.g., depending upon the
`desired viscosity and upon the specific polymer used, etc.).
`Furthermore, for hydrogels based on non-cellulose/non-cel-
`lulose derivative polymers, the polymer concentration can be
`lower or higher than the polymer concentration for cellulose/
`cellulose derivative hydrogels. For example, hydrogels based
`on poloxamer can comprise, e.g., from about 15% to about
`35%, from about 20% to about 30%, or about 25% polymer
`molecule to hydrogel solution, while pectin based hydrogels
`can comprise, e.g., about 3% to about 6%, or about 5%
`polymer to hydrogel solution and carrageenan based hydro-
`gels can comprise from about 2% to about 10% polymer per
`hydrogel solution. Furthermore, hydrogels based on polyvi-
`nyl pyrrolidone can comprise, e. g., about 10% or more poly-
`mer per hydrogel solution and hydrogels based on dextran can
`comprise, e.g., from about 5% to about 10% polymer per
`hydrogel solution, e.g., depending on the molecular weight of
`the dextran. Those of skill in the art will be familiar with a
`
`range of appropriate polymer concentrations for numerous
`different hydrogel constructions.
`[0006] Additionally, in the various methods, the chelator is
`typically an autoclave stable chelator (or temperature stable
`chelator) such as, but not limited to, an aminopolycarboxy-
`late, EDTA, NTA, EDDS, EGTA, PDTA, or DTPA. In many
`embodiments, the hydrogel comprises from about 50 to about
`2000 ppm chelator, from about 100 to about 1500 ppm chela-
`tor, from about 200 to about 1000 ppm chelator, from about
`300 to about 500 ppm chelator, or about 400 ppm chelator
`(e.g., EDTA), etc.
`[0007]
`Furthermore, the radical scavenging moieties in the
`methods ofthe invention can comprise, but are not limited to,
`methionine or methionine derivatives, or short peptides com-
`prising one or more methionine residues or methionine
`derivatives, etc. In embodiments comprising methionine, the
`hydrogel solutions can comprise from about 0.01 to about 10
`mg/ml, from about 0.05 to about 10 mg/ml, from about 0.1 to
`
`Page 11
`
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`

`US 2008/0226724 A1
`
`Sep. 18, 2008
`
`about 10 mg/ml, from about 0.15 to about 10 mg/ml, from
`about 0.2 to about 10 mg/ml, from about 0.5 to about 8 mg/ml,
`from about 1 to about 5 mg/ml, from about 1.25 to about 3
`mg/ml, from about 1.5 to about 2 mg/ml, or about 1.8 mg/ml
`methionine. In some embodiments, the radical scavenger
`moiety comprises a water-soluble free radical scavenger (e.g.,
`antioxidant), ascorbic acid or its derivatives (e.g., derivatives
`such as thiols, sulfites, metabisulfites, bisulfites, etc.), or
`phosphonates/phosphonic acids, etc. In embodiments com-
`prising methionine, the methionine can comprise any stere-
`oisomer or combination of stereoisomers of methionine, as
`well as peptides comprising one or more methionine residues.
`In embodiments comprising peptides or other molecules hav-
`ing more than one methionine residue, each methionine resi-
`due is typically counted separately in determining the
`methionine concentration. Thus,
`in embodiments having
`polypeptides comprising two methionine residues,
`the
`methionine concentration, for the same number of peptides,
`would be double that of those embodiments comprising
`polypeptides having just one methionine residue each.
`[0008]
`In particular methods, the hydrogel solutions com-
`prise a metal ion chelator and a radical scavenging moiety.
`For example, in particular methods, the hydrogel solutions
`comprise 400 ppm chelator (e.g., EDTA) and 1.8 mg/ml scav-
`enging moiety (e.g., methionine).
`[0009]
`In certain embodiments, the methods herein pro-
`duce hydrogels that after autoclaving and/or storage (e.g.,
`storage for at least 1 day, at least 2 days, at least 3 days, at least
`4 days, at least 5 days, at least 6 days, at least 1 week, at least
`2 weeks, at least 3 weeks, at least 4 weeks, at least 5 weeks, at
`least 6 weeks, at least 7 weeks, at least 8 weeks, at least 9
`weeks, at least 10 weeks, at least 11 weeks, at least 12 weeks,
`at least 25 weeks, at least 50 weeks, at least 1 year, at least 1.25
`years, at least 1.5 years, at least 1.75 years, at least 2 years, at
`least 2.25 years, at least 2.5 years, at least 2.75 years, at least
`3 years, at least 3.25 years, at least 3.5 years, or at least 3.75
`years or longer, at temperatures such as 5° C., at typical
`ambient room temperature such as 20-250 C., at typical
`human body temperature (either internal or body surface), or
`at 40° C., comprise a greater viscosity than similar hydrogels
`(e.g., hydrogels made of the same or substantially similar
`types of polymers) that do not comprise metal ion chelators
`and/or radical scavenger moieties such as methionine. Thus,
`in other words, the methods herein create hydrogels that
`maintain their viscosity to a greater extent than hydrogels that
`are not created through the methods of the invention. The
`hydrogels produced through the methods of the invention can
`maintain at least 5%, at least 10%, at least 15%, at least 20%,
`at least 25%, at least 30%, at least 35%, at least 40%, at least
`45%, at least 50%, at least 55%, at least 60%, at least 65%, at
`least 70%, at least 75%, at least 80%, at least 85%, at least
`90%, at least 95%, at least 96%, at least 97%, at least 98%, at
`least 99%, at least 99.5%, at least 100%, at least 120%, at least
`140%, at least 160%, at least 180%, at least 200%, at least
`225%, at least 250%, at least 275%, at least 300%, at least
`325%, at least 350%, at least 375%, at least 400%, at least
`425%, at least 450%, at least 475%, at least 500%, at least
`525%, at least 550%, at least 575%, at least 600%, at least
`625%, at least 650%, at least 675%, at least 700%, at least
`725%, at least 750%, at least 775%, at least 800%, at least
`825%, at least 850%, at least 875%, at least 900%, at least
`925%, at least 950%, at least 975%, or at least 1000% or
`more, greater viscosity over such periods (or after such peri-
`ods) as compared to similar hydrogels that do not comprise a
`
`metal ion chelator and/or a radical scavenger moiety. While
`the hydrogels created through the methods of the invention
`maintain their viscosity, hydrogels that are not created by the
`methods of the invention will tend to lose their viscosity over
`such periods, thus leading to the hydrogels of the invention
`having a “greater” viscosity than the other hydrogels.
`[0010] Also, in the various embodiments of the invention,
`the methods produce hydrogels that can comprise pharma-
`ceutically acceptable hydrogels and can also optionally com-
`prise one or more active agents (e.g., components that pro-
`duce or help to produce a desired result or outcome, e.g., in a
`subject, such as a prophylactic and/or therapeutic result).
`Such active agents can include, e.g., vascular endothelial
`growth factor, lidocaine, local anesthetics, etc. The methods
`can produce hydrogels that can also optionally include, e. g.,
`pharmaceutically acceptable excipients, buffers, etc. In some
`embodiments, the methods produce hydrogels suitable for
`topical wound dressings. In particular embodiments,
`the
`methods produce hydrogels comprising 400 ppm chelator
`(e.g., EDTA or DTPA) and/or 1.8 mg/ml scavenging moiety
`(e.g., methionine). In some embodiments, the methods can
`produce hydrogels that comprise 1.8 mg/mL methionine. In
`embodiments wherein the hydrogel is autoclave treated, any
`metal ion chelator can be added prior to such treatment, while
`any scavenging moiety (e. g., methionine) can be added after
`such treatment. In particular embodiments, the methods can
`produce hydrogels that comprise a composition as set forth in
`Table 1 herein. For example, the methods can produce a
`hydrogel that comprises (as measured in a one liter volume)
`0.2, 0.6, or 1.8 g/L rh VEGF, 0.26 g/L succinic acid (or
`between about 0.2 and about 0.3 g/L), 0.76 g/L succinic acid,
`disodium salt, hexahydrate (or between about 0.7 and about
`0.8 g/L), 37.8 g/L 0t,0t-Trehalose, dihydrate (or between
`about 37 and 38 g/L), 0.036 g/L Polysorbate 20 (or between
`about 0.03 and 0.04 g/L), 30 g/L Hypromellose (hydroxypro-
`pyl methylcellulose) (or between about 25 and 35 g/L), 1.8
`g/L Methionine-L (or between about 1.5 and 2.0 g/L), 0.1 g/L
`Benzalkoniun chloride solution (or between about 0.007 and
`0.15 g/L), and water to qs to 1 L at a pH ofabout 4.7 to about
`5.3, at a pH ofabout 5.0, or at a pH of5.0. Such hydrogels can
`optionally be autoclave treated, wherein any chelator is
`optionally added prior to autoclaving and any scavenging
`moiety (or the rh VEGF) is added after autoclaving.
`[0011]
`In some aspects, the invention comprises a hydrogel
`composition (optionally a pharmaceutically acceptable
`hydrogel) comprising a hydrogel solution (e.g., a solution/
`slurry comprising a hydrogel polymer and, e.g., buffer), one
`or more metal ion chelators (e.g., an autoclave stable chelator,
`such as an aminopolycarboxylate, EDTA, NTA, EDDS,
`EGTA, PDTA, or DTPA), and/or one or more radical scav-
`enging moieties (e. g., methionine, a methionine derivative, or
`one or more peptides comprising methionine or a methionine
`derivative, etc.).
`[0012]
`In various embodiments, the hydrogel is an auto-
`claved hydrogel, while in other embodiments, the hydrogel is
`a filtered or similarly treated hydrogel. In hydrogels that are
`autoclaved, the metal ion chelator, if present, can have been
`added prior to autoclaving, while the radical scavenger moi-
`ety, if present, can have been added after autoclaving.
`[0013]
`In various embodiments, the hydrogels ofthe inven-
`tion can comprise a plurality of polymer molecules, such as,
`but not limited to: polysaccharide molecules, cellulose mol-
`ecules, cellulose derivative molecules, methylcellulose mol-
`ecules, hydroxypropyl methylcellulose (hypromellose) mol-
`
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`Sep. 18, 2008
`
`ecules, carboxymethyl cellulose molecules, hydroxypropyl
`cellulose molecules, hydroxyethyl cellulose molecules,
`hyaluronic acid molecules, Carbopol® molecules (Noveon,
`Cleveland, Ohio) and their derivatives, alginate, sodium
`hyaluronate, gellan, carrageenan, pectin, gelatin, polyvinyl
`pyrrolidone, poloxamer, dextran, etc. The concentration of
`hydrogels herein can be quantified by percent polymer mol-
`ecule to hydrogel solution (weight/volume). For cellulose/
`cellulose derivative hydrogels, the polymer molecule (e.g.,
`methylcellulose, hydroxypropyl methylcellulose, hydroxy-
`ethylcellulose, Methocel® A4M, grade HEC hydroxyethyl
`cellulose, or Methocel® E4M) can comprise from about 1%
`to about 6% polymer molecule to hydrogel solution, from
`about 1.25% to about 5.5% polymer molecule to hydrogel
`solution, from about 1.5% to about 5.0% polymer molecule to
`hydrogel solution, from about 1.75% to about 4.5% polymer
`molecule to hydrogel solution, from about from about 2% to
`about 4% polymer molecule to hydrogel solution, from about
`2.25% to about 4% polymer molecule to hydrogel solution,
`from about 2.5% to about 3.5% polymer molecule to hydro-
`gel solution, or about 3% polymer molecule to hydrogel
`solution. It will be understood, however, that specific recita-
`tion of polymer concentrations in the various hydrogels
`herein should not necessarily be taken as limiting and that the
`methods (and the compositions) herein can also comprise
`lower or higher concentrations of hydrogel polymers in the
`hydrogels (e.g., depending upon the desired viscosity and
`upon the specific polymer used, etc.). For hydrogels based on
`non-cellulose/non-cellulose derivative polymers, the poly-
`mer concentration can be lower or higher than the polymer
`concentration for cellulose/cellulose derivative hydrogels.
`For example, hydrogels based on poloxamer can comprise,
`e.g., from about 15% to about 35%, from about 20% to about
`30%, or about 25% polymer molecule to hydrogel solution,
`while pectin based hydrogels can comprise, e.g., about 3% to
`about 6%, or about 5% polymer to hydrogel solution. Fur-
`thermore, hydrogels based on polyvinyl pyrrolidone can
`comprise, e. g., about 10% polymer per hydrogel solution and
`hydrogels based on dextran can comprise, e.g., from about
`5% to about 10% polymer per hydrogel solution. Those of
`skill in the art will be familiar with a range of appropriate
`polymer concentrations for numerous different hydrogel con-
`structions.
`
`In various embodiments, the hydrogels ofthe inven-
`[0014]
`tion can comprise from about 50 to about 2000 ppm metal ion
`chelator
`(e.g., an aminopolycarboxylate, EDTA, NTA,
`EDDS, EGTA, PDTA, or DTPA), from about 100 to about
`1500 ppm, from about 200 to about 1000 ppm chelator, from
`about 300 to about 500 ppm chelator, or about 400 ppm
`chelator. Alternatively or additionally, the hydrogels of the
`invention can comprise from about 0.01 to about 10 mg/ml,
`from about 0.05 to about 10 mg/ml, from about 0.1 to about 10
`mg/ml, from about 0.15 to about 10 mg/ml, from about 0.2 to
`about 10 mg/ml, from about 0.5 to about 8 mg/ml, from about
`1 to about 5 mg/ml, from about 1.25 to about 3 mg/ml, from
`about 1.5 to about 2 mg/ml, or about 1.8 mg/ml radical scav-
`enging moiety (e. g., methionine) per volume ofhydrogel. The
`radical scavenging moieties in the methods of the invention
`can comprise, but are not limited to, methionine or methion-
`ine derivatives, or short peptides comprising one or more
`methionine residues or methionine derivatives, etc. In some
`embodiments,
`the radical scavenger moiety comprises a
`water-soluble free radical scavenger
`(e.g., antioxidant),
`ascorbic acid or its derivatives (e.g., derivatives such as thiols,
`
`sulfites, metabisulfites, bisulfites, etc.), or phosphonates/
`phosphonic acids, etc. In embodiments comprising methion-
`ine, the methionine can comprise any stereoisomer or com-
`bination of stereoisomers of methionine, as well as peptides
`comprising one or more methionine residues. In embodi-
`ments comprising peptides or other molecules having more
`than one methionine residue, each methionine residue is typi-
`cally counted separately in determining the methionine con-
`centration. Thus, in embodiments having polypeptides com-
`prising
`two methionine
`residues,
`the methionine
`concentration (for the same number of peptides) would be
`double that of those embodiments comprising polypeptides
`having just one methionine residue each.
`In particular
`embodiments, the compositions comprise 400 ppm chelator
`(e.g., EDTA or DTPA) and/or 1.8 mg/ml scavenging moiety
`(e.g., methionine). In some embodiments (either autoclaved
`or not), the compositions comprise 1.8 mg/mL methionine
`(optionally without chelator). In embodiments wherein the
`hydrogel is autoclave treated, the metal ion chelator can be
`added prior to such treatment, while any scavenging moiety
`(e.g., methionine) can be added after such treatment.
`[0015]
`In particular embodiments, the hydrogel formula-
`tions herein can comprise a composition as set forth in Table
`1 herein. For example, the composition can comprise (as
`measured in a one liter volume) 0.2, 0.6, or 1.8 g/L rh VEGF,
`0.26 g/L succinic acid (or between about 0.2 and about 0.3
`g/L), 0.76 g/L succinic acid, disodium salt, hexahydrate (or
`between about 0.7 and about 0.8 g/L), 37.8 g/L 0t,(x-Treha-
`lose, dihydrate (or between about 37 and 38 g/L), 0.036 g/L
`Polysorbate 20 (or between about 0.03 and 0.04 g/L), 30 g/L
`Hypromellose (hydroxypropyl methylcellulose) (or between
`about 25 and 35 g/L), 1.8 g/L Methionine-L (or between
`about 1.5 and 2.0 g/L), 0.1 g/L Benzalkoniun chloride solu-
`tion (or 0.01% or 0.008% benzalkoniun chloride or between
`about 0.007 and 0.15 g/L), and water to qs to 1 L at a pH of
`about 4.7 to about 5.3, at a pH of about 5.0, or at a pH of5.0.
`Such hydrogels can optionally be autoclave treated, wherein
`any chelator is optionally added prior to autoclaving and any
`scavenging moiety (or the rh VEGF) is added after autoclav-
`mg
`
`In the compositions of the invention after autoclav-
`[0016]
`ing and/or storage (e.g., storage for at least 1 day, at least 2
`days, at least 3 days, at least 4 days, at least 5 days, at least 6
`days, at least 1 week, at least 2 weeks, at least 3 weeks, at least
`4 weeks, at least 5 weeks, at least 6 weeks, at least 7 weeks, at
`least 8 weeks, at least 9 weeks, at least 10 weeks, at least 11
`weeks, at least 12 weeks, at least 25 weeks, at least 50 weeks,
`at least 1 year, at least 1.25 years, at least 1.5 years, at least
`1.75 years, at least 2 years, at least 2.25 years, at least 2.5
`years, at least 2.75 years, at least 3 years, at least 3.25 years,
`at least 3.5 years, or at least 3.75 years or longer at tempera-
`tures such as 5° C., at typical ambient room temperature such
`as 20-250 C., at typical human body temperature (either inter-
`nal or body surface), or at 40° C., the hydrogels of the inven-
`tion comprise a greater viscosity than similar hydrogels (e. g.,
`hydrogels made of the same or substantially similar types of
`polymers) that do not comprise the metal ion chelator and/or
`the radical scavenger moiety. Thus, in other words, the hydro-
`gels of the invention maintain their viscosity to a greater
`extent than hydrogels that are not ofthe invention. The hydro-
`gels ofthe invention can maintain at least 5%, at least 10%, at
`least 15%, at least 20%, at least 25%, at least 30%, at least
`35%, at least 40%, at least 45%, at least 50%, at least 55%, at
`least 60%, at least 65%, at least 70%, at least 75%, at least
`
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`US 2008/0226724 A1
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`Sep. 18, 2008
`
`80%, at least 85%, at least 90%, at least 95%, at least 96%, at
`least 97%, at least 98%, at least 99%, at least 99.5%, at least
`100%, at least 120%, at least 140%, at least 160%, at least
`180%, at least 200%, at least 225%, at least 250%, at least
`275%, at least 300%, at least 325%, at least 350%, at least
`375%, at least 400%, at least 425%, at least 450%, at least
`475%, at least 500%, at least 525%, at least 550%, at least
`575%, at least 600%, at least 625%, at least 650%, at least
`675%, at least 700%, at least 725%, at least 750%, at least
`775%, at least 800%, at least 825%, at least 850%, at least
`875%, at least 900%, at least 925%, at least 950%, at least
`975%, or at least 1000% or more, greater Viscosity over such
`periods (or after such periods) as compared to similar hydro-
`gels that are not of the invention (e.g., those that do not
`comprise a metal ion chelator and/or a radical scavenger
`moiety). While the hydrogels of the invention maintain their
`viscosity, the hydrogels that are not of the invention will tend
`to lose their viscosity over such periods, thus leading to the
`hydrogels of the invention having a “greater” viscosity than
`the other hydrogels.
`[0017]
`In the various embodiments, the hydrogels herein
`can comprise pharmaceutically acceptable hydrogels and/or
`can comprise one or more pharmaceutically active agent such
`as vascular endothelial growth factor, lidocaine, local anes-
`thetics, etc. and/or pharmaceutically acceptable excipients,
`buffers, etc. In some embodiments, the hydrogels are topical
`wound dressings.
`[0018] These and other features of the invention will
`become more fully apparent when the following detailed
`description is read in conjunction with the accompanying
`figures and claims.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1, illustrates loss of gel viscosity over time in
`[0019]
`different lots of HPMC (without added chelator or radical
`scavenger) after autoclave sterilization.
`[0020]
`FIG. 2, Panels A and B, illustrates loss of gel vis-
`cosity over time in HPMC (without added chelator or radical
`scavenger) in the presence of various concentrations of
`hydrogen peroxide at 5° C. (Panel A) and 40° C. (Panel B).
`[0021]
`FIG. 3, Panels A and B, illustrates loss of gel vis-
`cosity over time in MC (without added chelator or radical
`scavenger) in the presence of various concentrations of
`hydrogen peroxide at 5° C. (Panel A) and 40° C. (Panel B).
`[0022]
`FIG. 4, shows the percent of gel viscosity remaining
`for autoclaved HPMC and MC hydrogels comprising EDTA,
`in the presence of various concentrations of hydrogen perox-
`ide.
`
`FIG. 5, Panels A through C, illustrates the percent of
`[0023]
`gel viscosity remaining over time in different autoclaved
`HPMC gels in the presence of various concentrations of
`hydrogen peroxide at 40° C., with Panel A showing HPMC
`gels comprising 400 ppm EDTA, Panel B showing HPMC
`gels comprising 1.8 mg/ml methionine, and Panel C showing
`HPMC gels comprising 400 ppm EDTA and 1.8 mg/ml
`methionine.
`
`FIG. 6, illustrates the mechanism of hydroxyl radi-
`[0024]
`cal cleavage of 1,4-anhydrocellobitol.
`[0025]
`FIG. 7, Panels A through C, illustrates the percent of
`gel viscosity remaining over time in different autoclaved
`HPMC gels in the presence of various concentrations of
`hydrogen peroxide at 5° C., with Panel A showing HPMC
`gels comprising 400 ppm EDTA, Panel B showing HPMC
`
`gels comprising 1.8 mg/ml methionine, and Panel C showing
`HPMC gels comprising 400 ppm EDTA and 1.8 mg/ml
`methionine.
`
`FIG. 8, Panels A and B, illustrates comparison of
`[0026]
`release characteristics of methylcellulose and HPMC
`(hypromellose) hydrogel formulations with 0.2 mg/mL rh
`VEGF (Panel A) and 1.8 mg/mL rh VEGF (Panel B).
`[0027]
`FIG. 9, Panels A through D, shows the percent vis-
`cosity, in various concentrations of H202 at 40° C. and 5° C.,
`of a 3% HPMC hydrogel comprising methionine (Panels A
`and B) as well as the percent of oxidized VEGF in the pres-
`ence of methionine in HPMC hydrogels (Panels C and D).
`
`DETAILED DESCRIPTION
`
`[0028] The present invention comprises viscosity stable
`hydrogel compositions and methods to decrease or prevent
`viscosity loss in hydrogels. Hydrogels as a class are useful in
`a wide range of applications. Pharmaceutical/biomedical
`uses for hydrogels are especially useful. Particular formula-
`tions and constructions of hydrogels can be used in, e.g.,
`contact lenses, lubrication of catheters, and as artificial skin
`or as artificial membranes (e.g., kidney membranes). Recent
`work has focused on the use ofhydrogels as wound dressings
`or covers, e.g., in order to protect wounds from infection, to
`create a proper healing milieu, or to allow for drug delivery
`from the hydrogel itself. See, e.g., U.S. Ser. No. 11/455,017,
`US. Ser. No. 60/691,909, and US. Ser. No. 60/794,008.
`[0029] However, it is often useful to have hydrogels of the
`proper viscosity in such applications. For example, in wound
`dressings, hydrogels with too low a viscosity may not prop-
`erly adhere to wound areas. Furthermore, even if a hydrogel
`has the proper viscosity when manufactured or applied, envi-
`ronmental conditions can often decrease the viscosity,
`thereby making the hydrogel less useful. Such viscosity loss
`can arise in several situations. For example, autoclaving a
`hydrogel can decrease its viscosity. Of course,
`it will be
`appreciated that such problem is especially of concern for
`certain hydrogel pharmaceuticals. Hydrogel pharmaceuticals
`need to be pharmaceutically acceptable for medical uses.
`Particular medical uses (e.g., ophthalmic use, use