Browsing by Author "RATHINAM, K"
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Item BIOAVAILABILITY OF THEOPHYLLINE FROM GLUTARALDEHYDE CROSS-LINKED CASEIN MICROSPHERES IN RABBITS FOLLOWING ORAL-ADMINISTRATION(JOURNAL OF CONTROLLED RELEASE, 1995) LATHA, MS; RATHINAM, K; Mohanan, PV; JAYAKRISHNAN, ATheophylline loaded bovine casein microspheres were prepared by the glutaraldehyde cross linking of an aqueous alkaline dispersion of the protein containing the drug in a non-aqueous dispersion medium. The cross-linking of the protein droplets was carried out via the organic phase by the addition of varying quantities of glutaraldehyde- saturated toluene. In vitro release of the drug was examined in simulated gastric fluid at 37 degrees C from spheres having three different cross-linking densities. The bioavailability of theophylline released from the microspheres of different cross-linking densities was studied in rabbits following single oral administration. Microspheres with higher cross-linking densities were found to sustain theophylline release even up to 24 h. The peak serum concentrations of such preparations were well within therapeutic limits. Determinations of in vitro/in vivo correlation based on the data showed that a fairly good relationship exists between in vitro and in vivo release. The study demonstrated the potential of cross-linked milk protein as a matrix for sustained release oral preparations.Item CASEIN AS A CARRIER MATRIX FOR 5-FLUOROURACIL - DRUG-RELEASE FROM MICROSPHERES, DRUG-PROTEIN CONJUGATES AND IN-VIVO DEGRADATION OF MICROSPHERES IN RAT MUSCLE(JOURNAL OF PHARMACY AND PHARMACOLOGY, 1994)Glutaraldehyde cross-linked casein microspheres were loaded with 5-fluorouracil (5-FU) from concentrated aqueous solutions of the drug after the microspheres were synthesized and cleaned. In-vitro release of the drug was examined in phosphate buffer in the absence and in the presence of protease at 37 degrees C. Drug release data showed that only about 20% of the drug is released in the absence of protease even after 5 days, while digestion of the matrix with protease released the entrapped drug completely in about 24 h. A protein-drug conjugate was synthesized via carbamoyl linkage using 6-(5-FU-1-yl)hexyl isocyanate and the drug release was examined in phosphate buffer at 37 degrees C. Release from the protein-5-FU conjugate was slower compared with the release from microspheres in the presence of protease. Implantation of placebo microspheres of different cross-linking densities in the gluteal muscle of rats showed no adverse tissue reactions over a one-year period. Histopathological examination of the tissues containing injected microspheres suggested that the biological life of casein microspheres in muscle is about 6 months, which is three times that of cross-linked albumin microspheres.Item EVALUATION OF BONE-WAX EXTRACT ON THE FREQUENCY OF CHROMOSOMAL-ABERRATIONS IN THE BONE-MARROW OF SWISS MICE(VETERINARY AND HUMAN TOXICOLOGY, 1993) Mohanan, PV; RATHINAM, KIndigenously developed bone wax was evaluated for cytogenetic effects of a saline extract of the bone wax. Swiss mice were assigned to 5 groups of 6 animals each. Groups I, II, III were given non-lethal doses of 2.5, 5.0 or 10.0 ml bone-wax saline extract/kg body wt and Groups IV and V received sterile 0.9% saline vehicle or cyclophosphamide ip as controls. After 24 h the mice were sacrificed by cervical dislocation. Bone marrow preparations were stained with Giemsa's stain and examined by light microscopy. Abnormalities such as numbers of chromosome gaps, breaks and translocations were noted. The bone-wax saline extract did not induce chromosomal aberrations in the bone marrow of Swiss mice under our laboratory conditions.Item HEPATIC STUDIES OF INTRAPERITONEALLY ADMINISTERED TRIS(2-ETHYL HEXYL)TRIMELLITATE (TOTM) AND DI(2-ETHYL HEXYL)PHTHALATE IN RATS(JOURNAL OF APPLIED TOXICOLOGY, 1990)Item HYDROGEL MICROSPHERES FROM CROSSLINKED POLY(METHYL METHACRYLATE) - SYNTHESIS AND BIOCOMPATIBILITY STUDIES(BULLETIN OF MATERIALS SCIENCE, 1989) JAYAKRISHNAN, A; THANOO, BC; RATHINAM, K; MANDALAM, KR; RAO, VRK; LAL, AV; MOHANTY, MItem IN-VIVO AND IN-VITRO EVALUATION OF A BIOMACHINABLE GLASSCERAMIC(BULLETIN OF MATERIALS SCIENCE, 1994) RATHINAM, K; SIVAKUMAR, R; SARASWATI, VIn this paper we describe the toxicological tests done on a machinable glassceramic, prepared at the Defence Metallurgical Research Laboratory. Tests show no toxicity and biocompatibility is inferred.Item INTERACTION OF TRIS (2-ETHYL HEXYL) TRIMELLITATE (HATCOL-200) COTTON SEED OIL AND NORMAL SALINE WITH PENTOBARBITAL SODIUM - A PROSPECTIVE APPROACH(CURRENT SCIENCE, 1989) RATHINAM, K; VEDANARAYANAN, PVItem INVIVO BIOCOMPATIBILITY OF ALIPHATIC SEGMENTED POLYURETHANE IN RABBIT(JOURNAL OF BIOSCIENCES, 1989) JAYABALAN, M; RATHINAM, K; KUMARY, TV; MOHANTY, MItem INVIVO BIOCOMPATIBILITY OF AN ALIPHATIC CROSS-LINKED POLYURETHANE IN RABBIT(JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, 1991)A cage implantation technique has been adopted in a rabbit animal model to investigate the biocompatibility of an aliphatic crosslinked polyurethane based on hexamethylene diisocyanate (HDI). In this study, four cages are represented; the cage containing the candidate polyurethane material, biomedical grade polyurethane (Tecoflex), the commercial grade polyvinylchloride (PVC), and an empty cage which were implanted subcutaneously in rabbits. Exudates were aspirated from these cages at 4, 7, 14, and 21 days postimplantation. Exudates were analyzed for variations in proteins, cell counts, and extracellular enzymes. Results with the four types of cage implants showed that the candidate polyurethane caused an inflammatory response comparable to that caused by medical-grade Tecoflex and the empty cage control.Item LECTIN-IMMOBILIZED ALBUMINATED POLYETHER URETHANE UREA - TISSUE COMPATIBILITY(CURRENT SCIENCE, 1987) RATHINAM, K; SHARMA, CPItem LONG-TERM SOFT-TISSUE RESPONSE TO METALS, CERAMICS AND COMPOSITES - A COMPARATIVE HISTOPATHOLOGICAL EVALUATION(BULLETIN OF MATERIALS SCIENCE, 1987) MOHANTY, M; RATHINAM, K; KARTHA, CCItem PREPARATION AND EVALUATION OF RADIOPAQUE HYDROGEL MICROSPHERES BASED ON PHEMA IOTHALAMIC ACID AND PHEMA IOPANOIC ACID AS PARTICULATE EMBOLI(JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, 1990)Item PULMONARY VASOSPASM IN RABBITS INFUSED WITH STROMA FREE HEMOGLOBIN SOLUTION(INDIAN JOURNAL OF EXPERIMENTAL BIOLOGY, 1989) MOHANTY, M; KUMARI, TV; RATHINAM, K; VIJAYAKUMARIItem STUDIES ON THE EFFECT OF DEGREE OF HYDROPHILICITY ON TISSUE-RESPONSE OF POLYURETHANE INTERPENETRATING POLYMER NETWORKS(BIOMATERIALS, 1992)Interpenetrating polymer networks of polyurethane and vinyl monomers such as polyacrylamide, polyvinyl pyrrolidone, poly(hydroxyethyl methacrylate) and poly(methyl methacrylate) were implanted intramuscularly in rabbits. Attempts were made to correlate the morphological aspects of the interpenetrating polymer networks to their histological response. A relatively increased hydrophillicity of hydrophobicity of the interpenetrating polymer networks as in the case of polyurethane-polyvinyl pyrrolidone and polyurethane-poly(methyl methacrylate) interpenetrating polymer networks, respectively, could elicit an inert response whilst degradation of materials promoted reactivity.