Development of Smart Polymers in Drug Delivery Application

Abstract

The polymers that respond to very small changes in the surrounding environment and display a significant macroscopic change are known as “smart polymers.” They respond to external stimuli such as temperature, pH, light, redox potential, electric and magnetic field, ionic factors. These polymers find applications many areas including drug delivery. The present work focuses on developing smart polymers as carriers for drug delivery application. Three different pharmaceutical applications have been explored (i.e.) synthesis of polymers for their use as excipients in tablets, developing a novel polymeric gum base for Medicated Chewing Gum (MCG) and synthesizing co-polymer hydrogel films. A combination of Chitosan and Polyvinyl alcohol co-polymers was selected to synthesize a smart polymer. The synthesis process was carried out using different initiators and crosslinking agents and the synthesized polymers were used as excipients in tablets and tested for drug release. An attempt has also been made to synthesize a novel polymeric gum base for Medicated Chewing Gum using hydrophilic polymers unlike elastomers which are resistant in environment and add to environmental pollution. The gum base and chewing gum formulations were optimized, chewing gum was made by direct compression method and tested for drug release using Fluconazole as a model drug. Another application explored was that of pH responsive hydrogel films. Chitosan and Polyvinyl alcohol co-polymers were synthesized using Ammonium Ceric Nitrate as initiator and Glutaraldehyde as crosslinking agent and hydrogel films were formed. Amoxicillin trihydrate, an antibiotic drug was used in the formulations and the films were tested for drug release in 0.1 N HCl (pH 1.2) and Phosphate buffer (pH 7.4). The films showed maximum drug release at acidic pH and the drug release at neutral pH was comparatively lower. Further, Design of Experiments (DOE) were conducted based on Response Surface Method and Box Behnken design was applied to determine the effect of polymer ratio, initiator and crosslinking agent on the pH responsive nature of films. The structural, morphological and thermal changes in films were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), tensile strength and water uptake capacity. Ex-vivo studies were carried out using gastric mucosa of rat for identifying the mucoadhesivenes of films. These formulations can be used for the treatment of gastric ulcers, stomach cancer caused by Helicobacter pylori bacteria which reside in the digestive tract and attacks the stomach lining.