PubMed · 8206298
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M Watanabe, T Tanaka, S Yokoyama, H Kobayashi. 1994. Methoxyacrylates having oxinimo side chains.. https://doi.org/10.1042/bst022067s
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Copolymers of N-(2-hydroxypropyl)methacrylamide with p-nitrophenyl esters of unsaturated phenoxyacetic acids and N-methacryloylglycylleucine and with acrylic acid were synthesized as polymer carriers for obtaining water-soluble polymer forms of an antibiotic gramicidin-S. The kinetics of the aminolysis of copolymers of N-(2-hydroxypropyl) methacrylamide (HPMA) which contain reactive p-nitrophenoxycarbonyl groups by gramicidin-S were investigated. It was established that aminolysis rate depends on the structure of the bridge group which binds p-nitrophenoxycarbonyl group to the main chain of the copolymer. On the basis of these copolymers of HPMA polymer amide and salt derivatives of gramicidin-S were obtained and their composition was determined. It was shown, that the antibacterial activity of these polymer derivatives of gramicidin-S depends on the bond type of the antibiotic with the polymer and attains a relatively high level for polymer salts of gramicidin-S.
A novel approach to immobilize nonuniform initial drug concentration profiles in multilaminated matrix devices utilizing photopolymerization techniques is presented. Solution polymerization of 2-hydroxyethyl methacrylate (HEMA) and diethylene glycol dimethacrylate (DEGDMA) in the presence of a model compound, acid orange 8 (AO8), was conducted using UV light and photoinitiators to construct a laminated matrix device. In this process, each layer was polymerized with a different AO8 concentration to form a nonuniform initial concentration profile in the matrix devices. The AO8 diffusion coefficients measured in this work were used in a concurrently developed model to predict the effects of nonuniform AO8 concentration profiles on AO8 release patterns. The release data predicted by the model agreed well with the experimentally determined data. The results indicate that a zero-order release pattern can be approximated by employing a suitable nonuniform initial drug concentration profile.
Ion exchange resins have several applications in pharmacy for controlled or sustained release of drugs. In the present study, effects of the ionic strengths of adsorption medium and dissolution medium on drug adsorption onto and release from a acrylic acid grafted poly(vinylidene fluoride) (PAA-PVDF) were studied. Despite their porosity, PAA-PVDF membranes act reasonable well as cation exchange membranes. It was observed, that ionic strength of adsorption medium, degree of grafting and concentration of propranolol-HCl in adsorption medium affect propranolol-HCl adsorption onto the membrane. The fluxes of smaller molecules (MW < 500) across the membrane decreased with ionic strength of buffer solution, whereas the fluxes of the large molecules (FITC-dextran, MW 4400) increased with ionic strength. Release rate of adsorbed propranolol-HCl from the membrane into phosphate buffer was greatly affected by ionic strength of adsorption medium. These results can be explained by a cation exchange process between membrane and cations present in the buffer solution and swelling behavior of the grafted PAA chains.