Kinetic study and in vitro drug release studies of nitrendipine loaded arylamide grafted chitosan blend microspheres

Hypertension continues to be a significant public health concern because of its associated morbidity, mortality, and economic impact on society. By the year 2025, 1.56 billion individuals will have hypertension. Nitrendipine, an antihypertensive drug, is used in this present study. Hydrophilic matrices are capable of controlling the release of the drug over an extended period. Microsphere based sustained drug delivery systems will provide a suitable alternative to reduce the side effects and increase the dissolution rate of the drug compared to oral drug delivery. We prepared drug encapsulated microspheres of acrylamide grafted chitosan (hydrophilic polymers) by the free radical mechanism. This mechanism involves the use of an initiator, potassium persulfate. Microspheres were synthesized from the grafted copolymers using water in oil emulsion technique with a cross-linking agent. Differential scanning calorimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy were used to characterize the sample. The microspheres at stomach media showed low drug release characteristics, while at the intestinal organ, the drug release prolonged for 14 h. From the drug release kinetic models, Higuchi and zero-order were found to be the best model for the three ratios based on the correlation coefficient. The diffusion component is less than 0.5, which indicates quasi-fickian diffusion. From the kinetic study results, we concluded that the formed acrylamide grafted chitosan microspheres deliver the drug through the diffusion mechanism. Nitrendipine loaded microspheres prepared using water in oil emulsion technique showed favorable sustained drug release behavior. (paper)