Formulation and characterization of calcium chloride guar gum microsphere of theophylline

Aim: The aim of the present work was to formulate and characterize an effective colonic drug delivery system for nocturnal asthma based on the time- and pH-dependent system. Materials and Methods: The microsphere of calcium chloride guar gum was prepared by using theophylline. It was prepared by the method of emulsification and coating was done by the method of solvent evaporation with the pH-sensitive eudragit polymers. The prepared microsphere was characterized by particle size, surface morphology, entrapment efficiency, and degree of swelling. Results: The drug release was confirmed by the in vitro drug release in various pH progression medium and dissolution medium. The controlled release of theophylline after a lag time was achieved with developed formulation for colon drug delivery. Conclusion: The pH-dependent solubility behavior of eudragit and gelling properties of guar gum are found to be responsible for delaying the release.