A pre-formulation study of a polymeric solid dispersion of paclitaxel prepared using a quasi-emulsion solvent diffusion method to improve the oral bioavailability in rats.

Objective: To preliminarily develop a surfactant-free, polymeric solid dispersion (PSD) of paclitaxel suitable for oral administration.

Methods: A co-solvent quench method was applied to screen the proper polymer matrix of the PSD which were prepared in a liquid system using a quasi-emulsion solvent diffusion method (QESDM). Three dissolution experiments and two in vivo tests in rats were used to explain the differences among the formulations.

Development of an osmotically-driven pellet coated with acrylic copolymers (Eudragit® RS 30 D) for the sustained release of oxymatrine, a freely water soluble drug used to treat stress ulcers (I): in vitro and in vivo evaluation in rabbits.

Purpose: To develop an osmotically-driven pellet coated with polymeric film for sustained release of oxymatrine (OMT), a freely water soluble drug.

Methods: Pellet containing OMT and sodium chloride (NaCl), an osmotically active agent, were prepared by extrusion/spheronization and then coated with acrylic copolymers (Eudragit(®) RS 30 D) by the fluidized bed coating process. In vitro release and swelling behavior studies were employed to optimize and to evaluate the sustained-release behavior from the osmotically-driven pellets with film coated.

A novel surface modified nitrendipine nanocrystals with enhancement of bioavailability and stability.

In this study, chitosan, a cationic polymer with positive charge, was introduced to modify the nanocrystals of nitrendipine with negative charge. The nanocrystals were prepared via precipitation-high pressure homogenization method. Then the nanocrystals were dispersed into chitosan solution, and the free chitosan was removed by centrifugation to obtain the chitosan modified nanocrystals, which remained the same particle size.

α-Tocopherol succinate-modified chitosan as a micellar delivery system for paclitaxel: preparation, characterization and in vitro/in vivo evaluations.

α-Tocopherol succinate hydrophobically modified chitosan (CS-TOS) containing 17 α-tocopherol groups per 100 anhydroglucose units was synthesized by coupling reaction. The formation of CS-TOS was confirmed by (1)H NMR and FT-IR analysis. In aqueous medium, the polymer could self-aggregate to form micelles, and the critical micelle concentration (CMC) was determined to be 5.

Nitrendipine nanocrystals: its preparation, characterization, and in vitro-in vivo evaluation.

The present investigation was undertaken with the objective of developing a solid formulation containing nitrendipine nanocrystals for oral delivery. Nitrendipine nanocrystals were prepared using a tandem precipitation-homogenization process. Then, spray drying, a cost-effective method very popular in industrial situations, was employed to convert the nanocrystals into a solid form.

Protamine modified metal ion-protein chelate microparticles for sustained release of interferon.

This study focuses on extending the release period of zinc-protein chelate through protamine modification. Recombinant human interferon-α-2b (rhIFN), a highly pleiotropic cytokine with a short intrinsic pharmacokinetic half-life when injected subcutaneously (∼2-6 h), was used as a model drug. Protamine modified zinc-rhIFN chelate microparticles were prepared by co-precipitating rhIFN with zinc and protamine.

Effect of crystal size on the in vitro dissolution and oral absorption of nitrendipine in rats.

Purpose: To investigate the effect of crystal size on the dissolution and oral absorption of nitrendipine, a poorly soluble drug, in rats.

Methods: Five types of nitrendipine crystal suspensions with different particle sizes (200 nm, 620 nm, 2.7 microm, 4.

Preparation of stable nitrendipine nanosuspensions using the precipitation-ultrasonication method for enhancement of dissolution and oral bioavailability.

The aim of this study was to prepare and characterize nitrendipine nanosuspensions to enhance the dissolution rate and oral bioavailability of this drug. Nanosuspensions were prepared by the precipitation-ultrasonication method. The effects of five important process parameters, i.

Insulin-S.O (sodium oleate) complex-loaded PLGA nanoparticles: formulation, characterization and in vivo evaluation.

S.O (sodium oleate) is an anionic surfactant, which is able to forman ionic complex with positively charged insulin at suitable pH. In a previous study, the insulin-S.

Preparation and in vitro evaluation of pH, time-based and enzyme-degradable pellets for colonic drug delivery.

The preparation of pH-dependent, time-based and enzyme degradable pellets was investigated for use as an oral colonic drug delivery system. It was expected that drug would be released immediately once the pellets reached the colon. The pellets were prepared using extrusion-spheronizing equipment and subsequently coated with three layers of three functional polymers by an air-suspension technique.