Quantification and determination of topical delivery of epidermal growth factor from semisolid formulations

In order to obtain a procedure to quantify EGF by ELISA from semisolid formulations different buffers and organic solvents were used, having different polarities and miscibility with water. We studied it from oil-in-water (o/w) cream, water-in-oil (w/o), polyethylene glycol (PEG) ointment, and a jelly. Precision, accuracy and selectivity were determined and variation coefficients were less than 10% after different extraction method with a recovery of 95.54 -108.98%. According to results, it is possible to estimate the EGF concentration with high precision and reproducibility. No statistically significant differences were detected, when compared a placebo extraction solution with the ELISA standard solution demonstrating that placebo does not produce interferences in the quantification of the molecule. To determine the delivery of the active ingredient from different preparations we used a static diffusion cell system to evaluate the release and penetrability of the active ingredient throughout abdominal pig skin. Results showed that release and penetrability of EGF increased proportionally with the hydrosolubility of the vehicle. Therefore, the rate was obtained in jelly, PEG > o/w > w/o. Additionally, PEG ointment and o/w cream allowed the highest distribution of labeled 125I EGF in the epidermis and dermis and receptor medium.