Showing papers by "Birla Institute of Technology, Mesra published in 1996"

Dynamic effects during a high-speed sinter-forging process

Abstract: The paper reports on an investigation into the various technological aspects of a high-speed sinter-forging process. Experiments were conducted and measurements were made in the development of barrelling, strain variations at the free surface and densilication during dry and lubricated high-speed cold forging of sintered copper powder discs. The relationship between the frictional stress at the interface and other process variables is discussed and an analysis is given for the calculation of pressure distribution and die load by the solution of the equations of equilibrium taking barrelling into consideration for axial symmetry and plane strain sinter-forging conditions. Results are discussed critically to illustrate the interaction of various processing parameters involved during high-speed sinter-forging process and are presented graphically.

Studies on melothria maderasapatana (linn). Cogn.

Abstract: This communication is a report of some preliminary studies followed by chemical investigations done on the aerial parts of Melothria maderaspatana (Linn) Cogn., a plant drug used in traditional system of medicine in India against a variety of diseases.

Sustained Release of Theophylline from Eudragit RLPO and RSPO Tablets

Abstract: Newer polymeric grades of Eudragit, RLPO and RSPO, were explored for their utilities by formulating a sustained-release tablet of theophylline as a model drug. Formulations selected on the basis of their lower polymer content and drug release content, over the period of 12 hr, were compared with the marketed formulation. These were evaluated for dissolution characteristics. In vitro release showed zero-order kinetics (r = 0.9879-0.994.5; p < 0.001). In vivo evaluations were carried out on healthy human volunteers (23 ± 2.68 years old; 48.64 ± 6.31 kg). Dissolution rate constant (k), Cmax, Tmax, AUC0-12, AUC0-24, and t1/2 were evaluated statistically by two-way ANOVA. Upon t test, a highly significant difference between test products and the marketed product was observed. Wagner-Nelson analysis of the in vivo data revealed controlled-release absorption profiles for selected formulations. Linear regression analysis of the mean % of dose absorbed versus mean in vitro release, resulted in statisticall...

In vitro evaluation of some ayurvedic antacids.

Abstract: The ayurvedic proprietary antacid preparations available in the Indian market were analysed for their antacid activity and compared with allopathic antacid preparations. This study urges the need for standardization of antacid products with in vitro parameters.

Further studies on chemical evaluation of lauha bhasma iii.

Abstract: Samples of marketed Lauha bhasma from different manufactures were evaluated chemically. Apart from the 81 -85% iron content, the 15-19% other constituents were determined therein. Ferrous ferric and total iron in a single aliquot were determined spectrophotometrically, Qualitative and chromatographic analysis indicate the presence of sodium, potassium, calcium copper and cobalt in the samples, silicious matter and traces of ascorbic acid were present while tannin was absent in Lauha bhasma . Quantitatively sodium and potassium were determined by flame spectrometry. Upon fractionation, water soluble and acid soluble contents were determined.

Transdermal Delivery of Verapamil Using Mixed Grades of Eudragit: Design, In-vitro and In-vivo Evaluation

Abstract: A matrix-dispersion-type transdermal drug delivery system of verapamil was designed and developed using different ratios of mixed polymeric grades of Eudragit. Formulations were selected on the basis of their drug release content and release pattern. These were evaluated for in-vitro dissolution characteristics using a Cygnus sandwich patch holder. The release followed Higuchi kinetics (r = 0.972-0.996; P < 0.001). In-vivo evaluation was carried out on healthy human volunteers (24.00 ± 0.82 y; 60.58 ± 6.29 kg). In-vitro dissolution rate constant (K) and pharmacokinetic parameters generated from plasma and urine were evaluated by two-way analysis of variance. Statistically excellent correlation was found between percentage of drug absorbed from patch vs Cmax, AUC0-24, AUC0-∞. The time at which maximum lowering of blood pressure was found coincided with the tmax. A highly significant difference (P < 0.001) was observed when Cmax and AUC0-∞ generated from plasma and urine data were compared but when k, t½e, ka, t½a were compared, the differences were not significant. We conclude that urinary excretion data may be used as a simpler alternative to blood level data in studying the kinetics of absorption.

Verapamil‐releasing Transdermal Drug Delivery Using Hydroxypropylmethylcellulose Matrices: Design, In‐vitro and In‐vivo Evaluation

Abstract: Verapamil-releasing transdermal delivery systems were designed and developed using different ratios of hydroxypropylmethylcellulose (HPMC) K4M, K15M, K100M. Formulations were selected on the basis of their drug-release content and release pattern. These were evaluated for in-vitro dissolution characteristics using a Cygnus' sandwich patch holder. The release followed Higuchi kinetics as its coefficient of correlation (r = 0.993–0.997; P 0.1) difference was observed. Urinary excretion data is suggested as a simpler alternative to blood level data in studying the kinetics of absorption and deriving the absorption parameter.