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Biomedical subjects

D S Sheorey

Publications and source records attributed to D S Sheorey.

9 recordsLinked to original sources
PubMedDate not supplied

Effect of solvents on the characteristics of rosin walled microcapsules prepared by a solvent evaporation technique.

Rosin microcapsules were prepared by a solvent evaporation technique using solvents with different rates of evaporation. Sulphadiazine was used as a model drug. The microcapsules were studied for their size, drug content, wall thickness, surface characteristics and in vitro release. The mean diameter increased and the drug content decreased as the rate of evaporation of the solvent increased. Fast evaporating solvents produced thick walled microcapsules with innumerable surface pores/cracks compared with slow evaporating solvents.

Capsules↗
PubMedDate not supplied

A new technique for the encapsulation of water insoluble drugs using ethyl cellulose.

A new technique for encapsulation of water insoluble drugs has been developed utilizing ethyl cellulose as a wall forming material. Ethyl cellulose was dissolved in a water immiscible, volatile organic solvent, containing sulphadiazine as a model drug. This dispersion was emulsified into an aqueous bentonite suspension and phase separation was induced by solvent evaporation. The effect of bentonite concentration, core to coat ratio, organic solvent, speed of agitation and temperature was studied with respect to the microcapsule size and size distribution, drug content, in vitro release and surface characteristics.

Bentonite↗
PubMedDate not supplied

Study of some improved shellac derivatives as microencapsulating materials.

Shellac was chemically modified to alter its permeability and to prevent its 'after hardening'. Various shellac derivatives such as with succinic anhydride, phthalic anhydride, ethylenediamine and myristic acid were prepared. Salicylic acid granules were coated and evaluated for flow properties, moisture absorption and release characteristics before and after ageing. These derivatives imparted better flow properties and showed excellent ageing properties.

Drug Compounding↗
PubMedDate not supplied

Release kinetics of drugs from rosin-glycerol ester microcapsules prepared by solvent evaporation technique.

Rosin-glycerol ester microcapsules containing sulphadiazine were prepared by solvent evaporation technique. The goodness of fit of the release data was tested with first order, Higuchi matrix model and Hixon-Crowell cube root law. All these models were sufficiently linear. Application of the differential rate treatment showed that release from most of the microcapsules followed first order equation. Whereas up to 40-50 per cent of release, a zero order, membrane controlled kinetics was observed, the release is apparently first order under nonsteady, state conditions.

Capsules↗
PubMedDate not supplied

Rosin coacervate microcapsules: effect of solvent on phase separation of rosin.

The effect of various solvent-non-solvent pairs on phase separation of rosin was studied visually and microscopically. The type of phase separated was found to be a function of viscosity of the solution rather than the dielectric constant of the solvent. Triangular phase diagrams were constructed and optimum coacervation conditions were determined. Of all the solvents tested, only ethanol and acetone yielded a coacervate phase.

Capsules↗
PubMedDate not supplied

Preparation and study of release kinetics of rosin pentaerythritol ester microcapsules.

Rosin was esterified with pentaerythritol and intermediate reaction products with different acid values were isolated. Microcapsules containing sulphadiazine were prepared by a solvent evaporation technique using these esters as wall materials. The microcapsules were evaluated for their size, drug content, and release characteristics in simulated gastric and intestinal fluids. The microcapsule size increased as the acid value of the ester decreased. The release of the drug was studied by using first-order, Higuchi and Hixon-Crowell cube root models. The release mechanism of the microcapsules is discussed.

Chemistry, Pharmaceutical↗