Formulation and Development of Diclofenac Topical Emulgels

Abstract

Introduction: Topical drug delivery system has been the most appropriate and convenient approach over the past two decades. Many conventional semisolid dosage forms such as creams, gels, and lotions found to have problems such as sticky in nature, lesser spreading coefficient, and stability issues.[1] To overcome such issues, a novel, stable topical drug delivery approach can be used to formulate successful drug delivery for hydrophobic drugs. In recent years, the concept of emulgel has gained significant interest in the topical drug delivery system.[2] An emulgel is a combination of emulsion and gel system, which is formulated by mixing emulsion either o/w or w/o with a gelling agent.[3] Emulgel provides several benefits such as better loading capacity, stability, controlled release, improved patient compliance, avoids first pass metabolism, and gastric complications.[4,5] In the present investigation, a model anti-inflammatory drug

Objectives: The present research work was aimed to develop a novel emulgel for Diclofenac to enhance the drug absorption by the topical application, which overcomes the demerits of oral dosage form and conventional gel system of Diclofenac.

Methods: Methodology Preparation of Diclofenac emulgel The gel phase and emulsion phase were prepared separately. First, the gel phase was prepared by dispersing the different concentrations of carbopol 934 in distilled water and mixed by a mechanical stirrer. The emulsion phases were prepared by the addition of varying amounts of span 20 in varying quantities of liquid paraffin followed by mechanical stirring. The aqueous phase of emulgel was prepared by incorporating tween 20 in distilled water with continuous stirring, then methyl and propylparaben were added in propylene glycol, and Diclofenac (0.5 g) was dissolved in ethanol, and both the solutions were mixed with water phase of the emulsion. Both the water and oil phases were heated at 70–80°C for 20 min. Later, the oily phase was added to the aqueous phase by gentle stirring and allowed to cool. Finally, the prepared emulsion was mixed with gel base in a 1:1 ratio by manual stirring to get a clear emulgel of Diclofenac.

Results: All the Diclofenac emulgels formulations were found to be homogenous and showed no clogging and lumps which indicate good texture of system. All formulation batches were found to be homogenous yellowish milky emulsions previously while emulgels were found to be whitish viscous creamy preparation. The pH of all the formulations was ranging in between 6.1-6.5 which is comparable to the human skin pH which is around. Emulgel is considered to be good if it takes minimum time to spread on the surface. Among the various gels studied F3 emulgel has better spreadability. The values of spreadability indicate that the gel is easily spreadable by small amount of shear.

Conclusions: In this study emulgels were prepared by using two different gel forming polymers in which the gel formulation with Carbomer 934 showed better clarity and stability for longer period of time. In the study it was observed that the concentration of tween80 and linseed oil have shown effect on viscosity, spreadability and in-vitro drug permeability.In terms of pH the observed value of all the formulations were comparable to human skin pH. All the formulation were found to be easily spreadable. In drug permeation study and drug release data showed that F6 formulation showed better drug release data compared to other formulations. So it is considered as the optimized batch. Hence, Diclofenac emulgel was successfully prepared and evaluated.