Gellan Gum‐Sodium Alginate Novel <i>p</i> H‐Sensitive Microspheres: Formulation and Characterization for Chronotherapy of Arthritis

Abstract Chronotherapy of arthritis that is to reduce the early morning pain in the joints using p H sensitive hydrogel microspheres for colon targeting is a novel approach. Novel ketoprofen‐loaded p H‐sensitive Gellan gum‐Sodium alginate (Gg‐NaAlg) microspheres were developed by emulsion crosslinking method using Ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The formulations were characterized by Scanning Electron Microscopy (SEM), Fourier Transforms Infrared Spectroscopy (FT‐IR), and Thermogravimetry. The influence of process parameters such as particle size distribution, drug encapsulation efficiency and matrix swelling has been investigated. The average particle size of microspheres varied from 50 to 100 μm giving an encapsulation efficiency of 70 %. Due to the p H‐sensitive swelling nature of microspheres, the drug was released in the colonic medium of p H of 7.4, but almost no release in acidic media. The kinetics of drug release was analyzed using empirical equations to understand the transport of drugs through polymeric matrices. Drug release was extended up to 10 hr and pulsatile release was observed depending upon the variation in the p H from stomach to colon region.