Design and Development of Transdermal Film and Gel Using Combination of Shorea robusta and Typha angustata for Wound Healing Activity

Abstract

Shorea robusta (Dipterocarpaceae) is a well known tree for its gum resins with oligomeric stilbenes and triterpenoids like asiatic acid, oleanane and ursane and well reported for its wound healing activity. Many formulations containing oil of S. robusta are available in market for treatment of wounds, burns and scars. Plants belonging to Typha genus have been mentioned in many traditional literatures of different countries for treatment of wound but till date complete scientific study with respect to phytopharmacology and formulation development has not been reported so far for the Indian specie Typha angustata. Inflorescence has been reported to be used in traditional systems of medicine for the treatment of wounds, burns and ulcers. In two of our preliminary studies, both the drugs exhibited significant wound healing property, when evaluted in incision and excision wound models in rats which led us to utilize the concept of synergism to develop more effective therapy for wound, so the major aim of the investigation was to “Design and Develop novel formulations like transdermal films and gels using combination of S. robusta with T. angustata for treatment of wounds. Present study also focuses on evaluation of anti inflammatory activity and anti bacterial activity for ethyl acetate extract of inflorescence of T. Angustata to check for the possibility of underlying mechanism for wound healing. The plants were collected, authenticated and processed to prepare ethyl acetate extract (EAE) of inflorescence of T. angustata and to prepare methanolic extract and oil (MEO) of S. robusta. Initial optimization and evaluations were conducted on the preliminary batches for the transdermal films using two different polymers i.e hydroxyl propyl methyl cellulose (HPMC) 50cps and 15 cps in the concentration range 2- 4% with plasticizers polyethelene glycol 400 (PEG400) and PG (20, 30 and 40%) using methanol as solvent. Physical evaluations (e.g. tensile strength, thickness, folding endurance and % elongation) were carried out and best batches were selected for drug loaded films using combination of T. angustata EAE and S. robusta MEO. For in-vitro release studies the transdermal films were administered to the Franz diffusion cells and the batches prepared with 4 % of HPMC 50 cps with 40 % of both plasticizers gave satisfactory release of both drugs. The UV method was developed by selecting the wavelength maxima for both the extracts and simultaneous equation was derived first time for the developed formulations to check release of both the drugs. The dissolution profile was indicative that all the batches effectively released 100 % drug with in 2 hr of time and dissolution is not the rate limiting step for the drug permeation into the systemic circulation.