Designing, optimisation & characterization of sustained release matrix pellets prepared by extrusion spheronization containing mixture of proteolytic enzymes.

A method for developing sustained release multiple unit dosage form consisting of pellets of a proteolytic enzyme blend using extrusion spheronization as a process is demonstrated in this paper. Effect of Cellulose and Methacrylate based polymers and plasticizers on stability of the enzyme blend are determined. The effect of type & concentration of the sustained release polymer, spheronization rpm and plasticizer on the yield & sphericity of pellets is studied. The results indicated that the SR pellets could be formulated for this enzyme blend using both HPMC K15 and EUDRAGIT RSPO. The best rpm for spheronization turned out to be 1200 rpm. Use of plasticizer improved yield and sphericity. Triethyl citrate was better over polyethylene glycol 400 and EUDRAGIT RSPO was better over HPMC K15 with respect to yield and sphericity of pellets. The pellets could be suitably enteric coated for protection of enzyme blend in lower pH of GIT. The in vitro release profile indicated release extension could be extended up to 12 hours in intestinal condition postulating to an acceptable bioavailablity in vivo.

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.