Synthesis and characterization of diltiazem loaded Eudragit RS 100 “Microsponges”.

In this study, we report successful synthesis of porous polymeric microspheres with “microsponge” type morphology by quasi-emulsion solvent diffusion method. Over the past few years the “Microsponge Delivery Systems - MDS” started to stand out as promising carriers in solid and semi-solid drug dosage forms providing a number of benefits for the purposes of cutaneous, mucosal and stomach/colon-targeted drug delivery. In order to evaluate the potential for sustained/controlled drug release of our “microsponges”, diltiazem was used as a model drug. Diltiazem-loaded microsponges were subjected to Scanning Electron Microscopy (SEM) for size and morphology assessment. Drug loading efficacy was evaluated after destruction of the particles in dichloromethane and spectrophotometric quantification. Compatibility study for drug and polymer was performed on FT-IR. In vitro dissolution test was carried out in PBS pH 7,4 and drug release kinetics was determined. The resulting particles showed desired spherical sponge-like morphology and mean size diameter of 59,09±13.00 μm. Satisfactory values of production yield and loading efficacy were observed – 82,78±0.34% and 90,66±1.65%, respectively. FT-IR revealed no chemical interaction between model drug diltiazem and polymer Eudragit RS 100. Drug release was found to follow zero-order kinetics and possessed drug release of 76,44% in 18 hours. These results might be taken in consideration for future studies concerning development of microsponge- enriched dosage forms.