A flexible technology for modified-release drugs: multiple-unit pellet system (MUPS).

Oral modified-release multiple-unit dosage forms have always been more effective therapeutic alternative to conventional or immediate release single-unit dosage forms. With regards to the final dosage form, the multiparticulates are usually formulated into single-unit dosage forms such as filling them into hard gelatin capsules or compressing them into tablets. There are many relevant articles and literature available on the preparation of pellets and coating technology. However, only few research articles discuss the issue of compaction of pellets into tablets. This review provides an update on this research area and discusses the phenomena and mechanisms involved during compaction of multiparticulate system and material and/or process-related parameters influencing tableting of multiparticulates to produce multiple-unit pellet system (MUPS) or pellet-containing tablets, which are expected to disintegrate rapidly into individual pellets and provide drug release profile similar to that obtained from uncoated pellets.

Evaluation of Sterculia foetida gum as controlled release excipient.

The purpose of the research was to evaluate Sterculia foetida gum as a hydrophilic matrix polymer for controlled release preparation. For evaluation as a matrix polymer; characterization of Sterculia foetida gum was done. Viscosity, pH, scanning electronmicrographs were determined. Different formulation aspects considered were: gum concentration (10-40%), particle size (75-420 microm) and type of fillers and those for dissolution studies; pH, and stirring speed were considered. Tablets prepared with Sterculia foetida gum were compared with tablets prepared with Hydroxymethylcellulose K15M. The release rate profiles were evaluated through different kinetic equations: zero-order, first-order, Higuchi, Hixon-Crowell and Korsemeyer and Peppas models. The scanning electronmicrographs showed that the gum particles were somewhat triangular. The viscosity of 1% solution was found to be 950 centipoise and pH was in range of 4-5. Suitable matrix release profile could be obtained at 40% gum concentration. Higher sustained release profiles were obtained for Sterculia foetida gum particles in size range of 76-125 microm. Notable influences were obtained for type of fillers. Significant differences were also observed with rotational speed and dissolution media pH. The in vitro release profiles indicated that tablets prepared from Sterculia foetida gum had higher retarding capacity than tablets prepared with Hydroxymethylcellulose K15M prepared tablets. The differential scanning calorimetry results indicated that there are no interactions of Sterculia foetida gum with diltiazem hydrochloride. It was observed that release of the drug followed through surface erosion and anomalous diffusion. Thus, it could be concluded that Sterculia foetida gum could be used a controlled release matrix polymer.

A flexible technology for modified release of drugs: multi layered tablets.

Modified release dosage forms offer definite advantages over conventional release formulation of the same drug. Hydrophilic polymers are mainly used for preparation of matrix type controlled delivery systems. The system usually provides nonlinear release profile. The multi-layered matrix system overcomes inherent disadvantages of non-linearity associated with diffusion controlled matrix devices by providing additional release surface with time to compensate for the decreasing release rate. This technology also demonstrates a wide flexibility for various applications. In this article, we review system design, various constructions and formulation parameters of modified release dosage forms.