Physicochemical properties, in vitro release and skin permeation studies of a topical formulation of standardized pomegranate rind extract

ABSTRACT

The aim of the present study was to develop a stable formulation containing standardized pomegranate rind extracts [SPRE] for topical use in the treatment of dermal diseases. Ellagic acid [EA] as the major active constituent of SPRE [not less than 13%] was quantified by HPLC as an indicator for studies on the stability, in vitro drug release, and skin penetration/retention. The formulation prepared with polyethylene glycols [PEG 400 and PEG 4000] containing 5% SPRE has been found to be stable and provide a release rate of 36.6741 +/- 5.0072 micro g/cm2 /h that was best fitted to the zeroorder kinetic model. EA from SPRE did not penetrate the full-thickness rat skin but the skin retention of EA was determined to be 2.22 +/- 0.16 micro g/cm2 with a total recovery of 95.14 +/- 5.51%. The results indicated that this 5% SPRE PEG ointment was of satisfactory physicochemical properties and worth further in vivo investigations