DEVELOPMENT AND EVALUATION OF CONTROLLED-RELEASE DILTIAZEM HCL MICROPARTICLES USING CROSS-LINKED POLY(VINYL ALCOHOL)

Hydrogels of cross-linked poly(vinyl alcohol) (PVA) were developed and their properties were evaluated as a controlled-release oral solid do sage form. The concentration of glutaraldehyde involved in cross-linki ng is directly proportional to the compactness of the three-dimensiona l networks of the cross-linked PVA. The theoretical calculations revea l that the release of diltiazem HCl from PVA could be described by the combination of Fickian and diffusion-controlled models. The confirmat ion of cross-linking was done by differential scanning calorimetry and infrared spectroscopy. The microparticles show lower percentage compr essibility but good flowability, hence a capsule dosage form was thoug ht to be suitable. The toxicity level of PVA was confirmed to be 10 g/ kg body weight. The microparticle formulation was optimized with respe ct to size distribution and increased drug loading. The microparticles were physically evaluated with respect to bulk density, angle of repo se, and percent compressibility. The microparticles released a drug fo r 12 hr. The microparticles had a drug loading of 61% to 67%.