HEMA/MMA

Tetrafilcon-A terpolymer of HEMA, MMA, and 42.5 Ao s oftAquaflex American Optical Corp.Cooper Vision,... 

Figure 5 The mutual diffusion coefficient, D, of sodium chloride as a function of reciprocal matrix hydration, H, in various methacrylate gels. HPMA-GMA polyfhydroxypro-pyl methacrylate-co-glyceryl methacrylate) HEMA polyfhydroxyethyl methacrylate) MMA-GMA poly(methyl methacrylate-co-glyceryl methacrylate) HEMA-MMA poly-(hydroxyethyl methacrylate-co-methyl methacrylate) HPMA-MMA polyfhydroxypropyl methacrylate-co-methyl methacrylate) HPMA-GDMA polyfhydroxypropyl methacry-late-co-glyceryl dimethacrylate). (From Ref. 64.)...

Hwang JR, Sefton MV. Effect of capsule diameter on the permeability to horseradish peroxidase of individual HEMA-MMA microcapsules. J Controlled Release 1997 49 217-227. 

Figure 5. Amount of absorbed fibrinogen on copolymer surface including hydrophilic domain at 37 C. GEMA glucosyloxyethyl methacrylate, HEMA 2-hydroxyethyl methacrylate, MMA methyl methacrylate, GEMA-MMA poly(GEMA-co-MMA), and HEMA-MMA poly(HEMA-co-MMA).

There is good agreement in wetting behavior between the AA/BMA film (16 mole % AA) cast from t-butanol and HEMA/MMA (5 mole %... 

The pharmacodynamic performance was studied for three drug-polymer matrix systems and comparisons were made between the In vivo and the In vitro results The systems studied were (a) gentamicin In silicone rubber, (b) tetracycline In HEMA/MMA copolymers, and (c) nlrldazole In silicone rubber. In general, the In vitro models fall short of predicting the actual In vivo results accurately, even In those cases where the controlled release of the agent showed positive, desirable results In the test animals. 

Sustained Release of Tetracycline From HEMA/MMA Copolymers... 

Nevertheless we have chosen an alternative approach microencapsulation using synthetic polyacrylates which may be stronger and more biocompatible (or at least have a more reproducible biocompatibility). Most of the effort has been with a particular water insoluble synthetic copolymer (HEMA-MMA), although other polyacrylates (water soluble or insoluble) have been used. In general, two approaches have been used complex coacervation with water soluble polycations and polyanions to generate an insoluble complex and simple coacervation with a water insoluble polymer precipitated from an organic solvent. 

HEMA, MMA, and MAA or DMAEMA (66, 67). Polymer molecular weight control was attempted by adjustment of initiator concentrator through the presumed inverse square root relationship between initiator level and kinetic chain length, (63) and this was reflected in measured intrinsic viscosities. Comparisons across a series are made difficult by changing Mark-Houwink-Sakurada coefficients. However direct comparisons may be made between polymers of similar composition, for example lc, 2c, and 3c, to show an expected increase in hydrodynamic volume from series 1 through series 3. 

Fig. 4, Equilibrium water content of solution cast films of high molecular weight polymers in distilled water (filled circles) and in phosphate buffered saline (open circles), (a) poly MMA, (b) 25/75 HEMA/MMA, (c) 50/50 HEMA/MMA, (d) 75/25 HEMA/MMA, (e) poly-HEMA. (/) poly-HPMA...

An interesting observation with 75% HEMA/25% MMA capsules was the propensity to harden when incubated in tissue culture phosphate buffered saline (PBS). Unlike the biochemist s PBS, tissue culture PBS (Dulbecco s PBS) contains 0.9 mM Ca + 2 (and 0.5 mM Mg + 2). This is a relatively unstable solution and incubation of HEMA-MMA capsules in this medium for even a few days lead to the formation of a calcium phosphate crust on the outside of the capsule. Presumably the polymer acted as a nucleation site for calcification. Such calcium deposits are absent when capsules are incubated in tissue culture medium or calcium free PBS. 

Sulfur removal from gasoline Copolymers of AN widi HEMA/MMA P ranging from 1.5 to 15. [193]... 

Monomers used MAA,TFM, HEMA, MMA,VPY, NVP (Fig. 4) Polymerization mixture EDMA, CH2CI2, AIBN (Fig. 4 )... 

Figures Illustration of common shear rheology measurements for photopolymerization reactions, (a) Evolution of dynamic viscosity with exposure time for HEMA, HEMA MMA, and MMA monomers photo-polymerized with Darocur 1173. The gel point is defined as the time at which viscosity goes to infinity, (b) Typical profile for modulus change in photopolymerizable gels. G and G" denoting shear (storage) and loss (viscous) moduli. Gel point is defined as when G -G".

SMA-HEMA/MMA The copolymerization of PSHA macromonomer with HEMA was carried out in THF-EtOH with AIBN. 

St-HEMA/MMA The copolymerization of PSt macromonomer with HEMA was carried out in DMF. It was found that it is not easy to obtain high molecular graftcopolymers and that methanol soluble fraction consisted of homopolymer of HEMA, Copolymer of MMA and HEMA was selected as a backbone to obtain high molecular graftcopol3nners. The results are shown in Table VI and Figure 6. 

Table VI. St-(HEMA/MMA) Graftcopol3nners feed Graf tcopol3niiers ...

Figure 6. GPC of St-HEMA/MMA graftcopol3nner (—) as compared with PSt macromonomer (-—).

Tetrafilcon-A Terpoljrmer of HEMA, MMA, and VP cross-linked with divinylbenzene 42.5 Aosoft Aquaflex American Optical Corp., Cooper Vision, Inc. 

Sefton MV, Crooks CA, Horvath V et al. HEMA-MMA copolymer for the microencapsulation of mammalian cells. Research Report 1990, University of Toronto. 

A number of papers have discussed the polymerisation of silicon-containing 4-membered ring monomers, DASCB [29-33]. Typical polymerisation conditions are /THF, nHx/nBuLi/ 48 C/ZCHsOH/. Block copolymers of methacrylates and S, HEMA, MMA, and tBMA were prepared with alkyl = Bu (Mn/(kg/mol) < 17 1.13 < Mw/Mn < 1.25 for HEMA block... 

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