Biomedical subjects

Aman Trehan

Publications and source records attributed to Aman Trehan.

4 recordsLinked to original sources

PubMed2005

Comparative study of different silymarin formulations: formulation, characterisation and in vitro/in vivo evaluation.

The aim of the present study was to study the synergistic hepatoprotective effect of silymarin with phospholipids when it is encaged in microspheres so as to passively target it to liver and to compare these silymarin formulations with silymarin solution. Various silymarin loaded lipid emulsions were formulated which include formulation A prepared with soyabean oil as an internal oily phase, soya lecithin as surfactant and tween 80 as cosurfactant; formulation B which was same as formulation A but was filtered through 0.45 micro membrane filter and finally steam sterilized for intravenous administration; formulation C containing soyabean oil as an internal oily phase, soya lecithin as surfactant, tween 80 and propylene glycol as cosurfactant/ cosolvent. These formulations were compared for their release profile with silymarin solution in propylene glycol, i.e. formulation D. In vivo evaluation was carried out using three models i.e. phenobarbitone induced sleep time in mice, biochemical estimation of SGOT and SGPT enzyme levels and histopathological examination of rat livers. Results revealed that there was significant reduction in sleep time in the mice treated with silymarin loaded lipid microspheres (both p.o. as well as i.v.) when compared with control and even with plain lipid microspheres and silymarin solution and significant reduction in enzyme levels in silymarin lipid microspheres treated group when compared with control, plain lipid microspheres as well as silymarin solution treated group. Histopathological studies also supported the results obtained from the other two models. A positive outcome of these studies gave an insight that if silymarin is coupled with phospholipid in such microparticulate delivery systems, hepatoprotective effect of drug molecules can be pronounced further by self targeting nature and synergistic action.

Administration, Oral↗

PubMed2003

Biodegradable microspheres for protein delivery.

In a very short time, since their emergence, the field of controlled delivery of proteins has grown immensely. Because of their relatively large size, they have low transdermal bioavailabilities. Oral bioavailability is generally poor since they are poorly absorbed and easily degraded by proteolytic enzymes in the gastrointestinal tract. Ocular and nasal delivery is also unfavorable due to degradation by enzymes present in eye tissues and nasal mucosa. Thus parenteral delivery is currently most demanding and suitable for delivery of such molecules. In systemic delivery of proteins, biodegradable microspheres as parenteral depot formulation occupy an important place because of several aspects like protection of sensitive proteins from degradation, prolonged or modified release, pulsatile release patterns. The main objective in developing controlled release protein injectables is avoidance of regular invasive doses which in turn provide patient compliance, comfort as well as control over blood levels. This review presents the outstanding contributions in field of biodegradable microspheres as protein delivery systems, their methods of preparation, drug release, stability, interaction with immune system and regulatory considerations.

Biodegradation, Environmental↗

PubMedDate not supplied

Formulation, characterization, and in vitro evaluation of silymarin-loaded lipid microspheres.

The objective of our study was to incorporate and evaluate Silymarin, a chemically defined natural hepatoprotective agent, in lipid microstructured systems. Various constituents of lipid microspheres--namely, internal oily core; surfactant such as soyabean lecithin; and cosurfactants such as span 20, tween 20, tween 80, and propylene glycol--were tried in different concentrations to optimize the final formulation characteristics such as globule size range, structural integrity, sustainability, and percent drug-holding capacity. The final formulation (formulation A) was characterized with respect to size and morphology using transmission electron microscopy and laser diffraction technique. The enhanced mean percent release of 56.70+/- 2.03% was observed in 36 hr from silymarin-loaded lipid microspheres (formulation A), as compared to 18.67 +/- 0.192% with silymarin solution (formulation B). Thus, a stable delivery system having synergistic hepatoprotective effect of silymarin and soyabean lecithin could successively be produced for passive targeting to the liver.

Chemistry, Pharmaceutical↗

PubMedDate not supplied

Formulation, characterization, and evaluation of ketorolac tromethamine-loaded biodegradable microspheres.

Ketorolac tromethamine has to be given every 6 hr intramuscularly in patients for acute pain, so to avoid frequent dosing and patient inconvenience we found it to be a suitable candidate for parenteral controlled delivery by biodegradable microspheres for the present study. Ketorolac tromethamine-loaded microspheres were prepared by o/w emulsion solvent evaporation technique using different polymers: polycaprolactone, poly lactic-co-glycolic acid (PLGA 65/35), and poly lactic-co-glycolic acid (PLGA 85/15). To tailor the release profile of drug for several days, blends of PLGA 65/35 and PLGA 85/15 were prepared with polycaprolactone (PCL) in different ratios. The results revealed that microspheres made with 1:3 (PLGA65/35:PCL) blend released 97% of the drug in 5 days as compared 97% in 30 days in with pure PLGA65/35 microspheres. Microspheres made with 1:1 (PLGA65/35:PCL) and 3:1 (PLGA65/35:PCL released 98% of the drug in 30 days. In microspheres made with 1:3 (PLGA85/15:PCL), almost the entire drug was released in a week whereas in batches made with pure PLGA85/15 and 3:1 (PLGA 85/15:PCL) more than 80% of the drug was released in 60 days as compared with 96% in 60 days in 1:1 (PLGA85/15:PCL). Higher encapsulation efficiency was obtained with microspheres made with pure PLGA 65/35. These formulations were characterized for particle size analysis by Malvern mastersizer that revealed particle size in range of 12-15 micron and 12-22 micron for microspheres made with polymer blends of PLGA 65/35:PCL and PLGA85/15:PCL, respectively. In pure PLGA65/35 and PLGA85/15, particle size was 28 micron and 8 micron, respectively. Surface topography was studied by scanning electron microscopy that revealed a spherical shape of microspheres. From our study it as concluded that with careful selection of different polymers and their combinations, we can tailor the release of ketorolac tromethamine for long periods.

Animals↗