In Vitro Release of Sodium Diclofenac from Poloxamer 188 Modified Montmorillonite as an Oral Drug Delivery Vehicle

The aim of the present work was to investigate poloxamer 188 (F-68) modified montmorillonite (Mt) clay as an oral drug delivery vehicle for in vitro release of anti-inflammatory drugdiclofenac sodium (DS). The clay (Mt) was treated with F-68 and the synthesized modified Mt, (F-68-Mt) was characterized by X-Ray diffraction (XRD) studies (which confirmed the intercalation of F-68 in the clay interlayers) and Fourier transformed infrared (FTIR) studies. The adsorption of diclofenac sodium on to the synthesized F-68-Mt was then studied as a function of pH of the aqueous drug solution, contact time and initial drug concentration. A maximum drug loading of 107.5 mg/g was obtained. The optimal drug adsorbed F-68Mt composite was subsequently characterized by XRD studies (which confirmed the drug to be intercalated in the clay interlayers); FTIR, differential scanning calorimetric (DSC), thermogravimetric (TG), zeta potential, scanning electron microscopic (SEM) and high resolution transmission electron microscopic (HRTEM) techniques. The HRTEM image of the drug loaded sample (F-68-Mt-DS) shows the presence of drug particles less than 10 nm in dimension. The in vitro drug release studies of the intercalated drug in simulated intestinal fluid (PBS 7.4) exhibited a prolonged release as compared to the pure drug.