Formulation and in vitro Evaluation of Dapsone Topical Gel 5%

Dapsone gel (5%) is found to be effective in treating acne. The study was to develop a topical formulation of dapsone in Iran.

Determination of appropriate formulation for generic form of this drug in the treatment of acne.

Samples of the base of gel were made in the range of 0.3%-5% by dissolving Carbomer 934P in distilled water, and their physical properties and pH were evaluated. Then, Dapsone was dissolved in its appropriate solvent, diethylene glycol monoethyl ether (DEG) and were introduced into gel base. Afterwards, using Design Expert software 13 samples and in the next step 17 samples were designed, made and their rheological properties and pH were evaluated. Then, two formulations were selected and were characterized by drug content, physicochemical properties, rheology and stability and found to be in accordance with the US Pharmacopeia.

The gel bases containing carbomer in the range of 1-3% were appropriate. The pH value of gel bases in first 13 samples were between 5-7 and the viscosity range between 16530-2980000(cp). The viscosity of range of 17 designed samples was between 1100-760000(cp). The final sample with 1% carbomer content had the viscosity range of 14075-268000(cp) and drug release of 78/1% after 3 hours. The sample with 2% carbomer content had the viscosity range of 92660-557000(cp) and drug release of 76% after 3 hours.

Viscosity and drug release of both samples were in accordance with pharmacopeia. However, the sample containing 1% carbomer is more commercially suitable and more appropriate lowering pH of the skin.