Title : In vitro model of diclofenac sodium gel delivery through pig skin
At first sight transdermal drug delivery appears to be a simple form of treatment, but closer examination reveals that dermatological form doses represent one of the most difficult aspects of the science of pharmaceutical formulation. Modern formulation methods nowadays, however, have to concentrate on biopharmaceutical principles. The idea is to formulate topical pharmaceutical drugs that improve the delivery of the active principles in the local target site of action by selection of the best and appropriate vehicles. The vehicle composition can affect drug release, and a number of vehicles, including simple creams, gels and emulsion based formulations (Emulgel) have been utilized in topical preparations. Gel based formulations are better percutaneously absorbed than creams and ointment bases. From the literature, the formulation with HEC gel base exhibited better properties for topical delivery of drugs when compared with the other formulations.
Diclofenac sodium (DS) is a nonsteroidal anti-inflammatory drug (NSAIDs) widely used clinically to reduce inflammation and pain. The present research has been undertaken with the aim to develop topical hydrophilic gels of diclofenac sodium 1% and evaluation of in vitro drug release of diclofenac sodium through pig skin using vertical diffusion cell comparing with diclofenac commercial gels.
In the presented work were prepared three batch hydrophilic diclofenac sodium gels (DC) of hydroxyethylcellulose (HEC). Skin permeability of the preparations were evaluated in vitro using abdominal hairless pig skin, into water medium at 370C and determined using spectrofotometer UV at 276 nm. For each formulation were evaluated the cumulative drug release and were calculated the plots of release rate of DS.
The HEC diclofenac sodium gels were clearly transparent. All preparations were easily spreadable, with acceptable bioadhesion and fair mechanical properties. The pH values ranged from 7.33 to 8.35, which are considered acceptable to avoid the risk of irritation after skin application.
From the study was concluded that HEC gels containing diclofenac showed good homogeneity, spreadability, pH value and rheological properties within the limits allowed for dermatological preparations. HEC DS gels exhibited significantly better drug release when compared to commercial gel.
Audience take away:
• A new topical hydrophilic vehicle for dermatological formulation
• A easy way to realize a vertical diffusion cell
• A appropriate in vitro method proposed with the used of abdominal pig skin as a useful dialyze membrane