Characterization and in vivo evaluation of novel lipid-chlorambucil nanospheres prepared using a mixture of emulsifiers for parenteral administration.

Purpose: The purpose of the study was to develop and evaluate different lipid-based formulations for parenteral administration, as potential novel carrier systems for lipophilic drugs, and to turn an unstable drug such as chlorambucil into a useful one.

Methods: A two-stage, high-pressure homogenizer was used to yield a very fine monodispersed lipid nanosphere. The strategy of combining egg yolk phospholipid and nonionic emulsifier (Lutrol F 68 and Tween 80) as an emulsifier mixture was adopted to increase safety and tolerance.

A simple and rapid high-performance liquid chromatography method for determination of alendronate sodium in beagle dog plasma with application to preclinical pharmacokinetic study.

A simple and rapid high performance liquid chromatographic (HPLC) method for quantifying alendronate in beagle dog plasma was developed, validated and applied to a pharmacokinetic study. The sample preparation involved coprecipitation with CaCl(2) and derivatization with o-phthalaldehyde. Chromatographic separation was achieved on a Diamonsil C(18 )(250 x 4.

Application of mixture experimental design to simvastatin apparent solubility predictions in the microemulsifion formed by self-microemulsifying.

Self-microemulsifying drug delivery systems (SMEDDS) are useful to improve the bioavailability of poorly water-soluble drugs by increasing their apparent solubility through solubilization. However, very few studies, to date, have systematically examined the level of drug apparent solubility in o/w microemulsion formed by self-microemulsifying. In this study, a mixture experimental design was used to simulate the influence of the compositions on simvastatin apparent solubility quantitatively through an empirical model.

Part I: characterization of solid dispersions of nimodipine prepared by hot-melt extrusion.

The purpose of this study was to prepare and characterize solid dispersions of nimodipine with hydroxypropyl methylcellulose (HPMC, Methocel E5), polyvinylpyrrolidone/vinyl acetate copolymer (PVP/VA, Plasdone S630), and ethyl acrylate, methyl methacrylate polymer (Eudragit EPO). The goal was to investigate whether the solid dispersion prepared by hot-melt extrusion can improve the dissolution rate of nimodipine. The dissolution results indicated that three polymers are suitable carriers to enhance the in vitro dissolution rate of nimodipine in pH 4.

Part II: bioavailability in beagle dogs of nimodipine solid dispersions prepared by hot-melt extrusion.

The aim of the present work was to investigate the in vitro dissolution properties and oral bioavailability of three solid dispersions of nimodipine. The solid dispersions were compared with pure nimodipine, their physical mixtures, and the marketed drug product Nimotop. Nimodipine solid dispersions were prepared by a hot-melt extrusion process with hydroxypropyl methylcellulose (HPMC, Methocel E5), polyvinylpyrrolidone/vinyl acetate copolymer (PVP/VA, Plasdone S630), and ethyl acrylate, methyl methacrylate polymer (Eudragit EPO).

Development and mathematical simulation of theophylline pulsatile release tablets.

Theophylline pulsatile release tablets consisting of a fast-swelling core with a water-insoluble ethylcellulose were developed. Effects of coating material, the amount of the plasticizer, subcoating, the type of the disintegrant, and coating level on the release profiles were investigated. Results showed that ethylcellulose was the best candidate polymer for pulsatile release tablets.