Quality by design approach for developing emulgel of diclofenac with central composite design and evaluation using In vitro release testing

Topical route of drug administration is more effective therapy for improving patient compliance and bioavailability. The topical administration of analgesics allows effective and painless deliverance of medicament with least side-effects. This investigation was aimed to develop and evaluate Diclofenac emulgel for topical drug delivery with enhanced anti-inflammatory and analgesic potential. Diclofenac is used as a first-line drug for acute and chronic pain and inflammation from a variety of causes. When applied topically the advantage of the drug is the avoidance of the first-pass metabolism, better patient compliance and site-specific for their action. Emulgel was prepared by using HPMC K4M as a gelling agent, light liquid paraffin as the oil base, Kollicream 3C and Kolliphor CS20 as emulsifiers via the QbD method. The emulgel formulation of diclofenac was optimized by central composite design and determines the effect of excipients on in vitro release. Emulgel formulation was evaluated for pH, drug content, viscosity, in vitro drug release and stability study. Optimized formulation showed pH, drug content and viscosity in an acceptable range. Based on the results of this investigation, it was summarized that diclofenac emulgel has a promising potential as an alternative to the conventional marketed dosage form.