Acta Pharm. 64 (2014) 299-309

full paper

Original research paper

Development of novel formulations to enhance in vivo

transdermal permeation of tocopherol

ALY H. NADA, ABDELAZIM A. ZAGHLOUL, MOHSEN M. HEDAYA and IBRAHIM S. KHATTAB^a

alynada@hsc.edu.kw, alynada@gmail.com

Department of Pharmaceutics, Faculty of Pharmacy, Kuwait University, Kuwait

^a Current address: Kuwaiti Saudi Pharmaceutical Company (KSPICO), Kuwait

Accepted May 26, 2014

Tocopherol represents a big challenge for transdermal permeation owing to its extreme hydrophobicity and large molecular mass. The aim of the present study was to develop alpha-tocopherol (T) topical formulations and evaluate the ex vivo and in vivo permeation. Franz diffusion cells were used for the ex vivo permeation, and neonatal rats were used for in vivo permeation. Seven gel formulations and 21 liquid formulations were investigated for physical stability, viscosity and permeation of T. Analysis of T was performed by a validated HPLC method using a UV detector.The ex vivo permeation from gel and emulsion formulations was very poor (0.001–0.015 %). The highest permeation was observed from monophasic liquid formulations containing dimethyl sulfuxide (DMSO), tocopheryl polyethylene glycols (TPGs), propylene glycol, ethanol, and 9.5 % T. The in vivo results demonstrated higher retention in the epidermis compared to subcutaneous tissues; 1377 and 1.13 µg g^–1, respectively. Increasing T concentration from 4.8 to 9.5 % did not increase the amount permeated or % of T retained. It was concluded that simple solutions of T in presence of DMSO and TPGs are more promising systems for effective transdermal permeation; compared to gel, emulsion or oleaginous systems.

Keywords: tocopherol, topical formulation, chemical analysis, ex vivo and in vivo, skin barrier