Distribution of fibroblast growth factor‐2 (FGF‐2) within model excisional wounds following topical application

Objective To characterise the magnitude and distribution of fibroblast growth factor‐2 (FGF‐2) following topical application in hypromellose gel and film formulations or a solution in an animal wound model, in order to assess the potential of this route for treatment of chronic wounds. Method Topical formulations of FGF‐2 were applied to punch biopsy wounds, and FGF‐2 levels within the wound measured. Each 12 mm diameter wound received 0.3 μg FGF‐2 in solution, a 7% (w/w) hypromellose gel, a dried hypromellose film on Melolin‐backing or a saline control. After 2, 5 or 8 h the wounds were horizontally dissected into four sections (surface granulation, subcutaneous fat, superficial muscle and deep muscle) which were then analysed for FGF‐2 concentration using ELISA. Confocal microscopy was used to evaluate the distribution of FGF‐2 within the wound. Key findings There were significant differences in the mean FGF‐2 levels with respect to formulation and time following application (P < 0.05). FGF‐2 penetrated faster into tissue when formulated as a solution than as a gel or a film. There did not appear to be a significant difference between the gel and the film with respect to total concentrations achieved in the tissue, although confocal microscopy showed differences in FGF‐2 distribution within the wound. Conclusions Delivery of FGF‐2 to wounds in a solution gave the greatest increase in tissue FGF‐2 concentration when measured by ELISA and visualised using confocal microscopy. Gel and film formulations prolonged the release of FGF‐2 into the wound, although FGF‐2 levels were not significantly different from controls when measured by ELISA. Confocal microscopy highlighted the differences in the penetration and distribution of the FGF‐2 within the wound when released from different formulations.