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Biomedical subjects

A R Ray

Publications and source records attributed to A R Ray.

15 recordsLinked to original sources
PubMed1998

Sustained release of antimicrobial drugs from polyvinylalcohol and gum arabica blend matrix.

Synthetic polymers are widely used in biomedical applications. Polymer blends have recently paved their way in this field. An attempt to prepare blend of synthetic polymer polyvinylalcohol and natural macromolecule gum arabica is made in this paper. Characterization of these blends by NMR, DSC and viscoelastic studies reveal preparation of a blend composition with synergistic properties. The blend composition with synergistic properties was used to release various antimicrobial drugs. The duration and release of the drug depends on the amount of drug loaded in the matrix and solubility of the drug in the matrix and release medium. The advantage of this system is that the release kinetics of the drug from the system can be tailored by adjusting plasticizer, homopolymer and crosslinker composition depending on the drug to be released.

Anti-Bacterial Agents↗
PubMed1994

Sustained release of ferrous sulfate from polymer-coated gum arabica pellets.

Sustained release of ferrous sulfate (FeSO4) from gum arabica pellets has been achieved for 7 h. Release is further sustained for 12 to 600 h by coating the pellets with polyvinyl acetate and ethylene vinyl acetate, respectively. An increase in the amount of gum arabica in the pellets decreases the rate of release due to the gelling property of gum arabica. The gel layer acts as a barrier and retards the rate of diffusion of FeSO4 through the pellet. In coated pellets, an increase in thickness of membrane helps to sustain the release of FeSO4 for a longer duration. Thus, the release of FeSO4 can be sustained for the required duration by adjusting the amount of gum arabica in the pellet and the composition and thickness of polymeric coat. The mechanism of release accordingly varies from Fickian to zero-order and super case II transport.

Chemical Phenomena↗
PubMed1991

Antibacterial multifilament nylon sutures.

Multifilament nylon fibers were made antibacterial by dopping with iodine. Nylon fibers were immersed in acetone solution of iodine for 48 hours at room temperature for dopping of iodine. It was observed that iodine uptake by the nylon fibers increased with the increase in concentration of iodine in the solution. Antibacterial activity of these iodine dopped samples was evaluated by measuring the zone of inhibition. The bacterial species used for this study were Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Klebsiella pneumoniae. Iodine dopped fibers exhibited good antibacterial activity against these bacterial species. Release of iodine in distilled water is sustained for about 30 days. Antibacterial activity of the fibers decreases with the release of iodine in water. Ultra-violet and visible spectroscopic studies showed that tri-iodide ions were released from the dopped samples in the aqueous medium. These I3- ions might be responsible for the observed antibacterial activity. Fiber shrinks on iodine dopping leading to increase in the denier of the fiber. However effect of iodine dopping on the breaking load of fibers is not significant.

Anti-Infective Agents, Local↗
PubMed1990

Radiation-induced graft copolymerization of methacrylic acid on to poly(vinyl chloride) films and their thrombogenicity.

Methacrylic acid (MAA) was radiation grafted on to poly(vinyl chloride) (PVC) films to improve the blood compatibility of PVC. The thromobogenicity of MAA grafted PVC was evaluated by thrombus formation, platelet adhesion and haemolytic activity in vitro. The hydrophilicity of grafted PVC films was investigated by contact angle measurement. Methacrylic acid grafted PVC film showed lower thrombogenicity than that of PVC. It was found that the weight of thrombus formed on grafted PVC was less than that of PVC and glass and decreased with the increase in the graft level. The adhesion of platelets on grafted PVC was retarded after grafting with MAA hydrogels.

Biocompatible Materials↗
PubMed1984

Effect of anionic polymeric hydrogels on spermatozoa motility.

The effects of a few synthetic polymers on the motility of human spermatozoa in vitro have been studied. An alternate copolymer of styrene and maleic anhydride, poly(S-MA), poly (styrene-maleic acid), poly(S-MC), poly(hydroxy-ethyl methacrylate-methacrylic acid) copolymer, poly(HEMA-MAC), poly(HEMA) homopolymer and poly(MAC) homopolymer were chosen for this purpose. It was found that all the carboxylic acid containing polymers are strong inhibitors of the motility of spermatozoa. Poly(HEMA) did not have any inhibitory effect on the motility of spermatozoa.

Contraceptive Agents, Male↗
PubMed1982

Novel mode of contraception using polymeric hydrogels. I.

A new method of fertility control has been proposed and tested. The technique involves the use of the polymer, which when injected into the vas deferens lowers the pH sufficiently so as to kill the spermatozoa passing through. The polymer provides an acidic environment for a prolonged time and slowly erodes. The fertility may be restored after complete solubility of the polymer itself over a period of time or by flushing it with a suitable solvent. This method of male contraception is nonsurgical, nonocclusive, and reversible.

Contraception↗
PubMed1981

An insulin delivery system from oxidized cellulose.

Cellulose oxidized with periodate (OC) has been shown to be a biocompatible, biodegradable matrix suitable for immobilization and sustained release of drugs. In the present work, insulin was immobilized on the OC-matrix and the release profile in vivo and in vitro was examined. The hormone is bound to the matrix by Schiff's bond formation and is released by hydrolysis of this bond as well by degradation of the OC-matrix. The release can be sustained over longer periods by reducing the Schiff's base with NaBH4. The insulin depots could be conveniently injected as suspensions and are able to maintain glucose levels in diabetized rabbits at normal values over several days.

Animals↗
PubMed1979

Injectable non-occlusive chemical contraception in the male-I.

A new contraceptive technique has been proposed and tested. The method uses a novel polymer which when injected into the vas deferens, lowers the pH sufficiently kill the spermatozoa passing through. The polymer itself does not degrade in the process but can be flushed out to regain fertility. Experiments carried out on rats demonstrate the efficacy of the technique so as to have non-surgical, non-occlusive and reversible male contraception.

Animals↗
PubMed1979

Potential biosoluble carriers: biocompatibility and biodegradability of oxidized cellulose.

The biocompatibility and biodegradability of periodate oxidized cellulose is assessed in vivo. Morophological and histopathological studies over a period of six months indicate that oxidized cellulose degrades slowly without producing excessive tissue reaction. Preliminary investigations on the kinetics of degradation of oxidized cellulose in vitro, immobilization of alpha-chymotrypsin on it and the rate of the enzyme release in a solution of pH 7.4 are also briefly reported.

Animals↗