DIFLUNISAL TRANSETHOSOMAL GEL FOR TOPICAL DRUG DELIVERY: FORMULATION AND CHARACTERIZATION

Abstract

Transethosomes are modern vesicular systems designed to enhance the transdermal delivery of various types of drugs, including lipophilic and hydrophilic drugs. This system features a flexible and easily deformable membrane resulting from the combination of phospholipids, ethanol, and surfactants as edge activators. Diflunisal, a lipophilic non-steroidal anti-inflammatory drug classified in the BCS class II, requires a delivery system that can overcome the limitations of permeation through the skin. The objective of the present research work is to develop a diflunisal-loaded transethosomal system, incorporate it into gel formulations, and characterize the developed transethosomal gel to optimize its applicability for topical delivery. Diflunisal transethosomes were produced by thin film hydration and sonication using Phospholipon 90G and Span 80 as edge activators in 30% ethanol. The vesicles were characterized based on their size, zeta potential, entrapment efficiency, and polydispersity index. The transethosome suspension was incorporated into Carbopol 934 gel at 0.5%, 1%, and 2%. The gels were tested for organoleptic properties, homogeneity, pH, viscosity, and spreadability. Transethosomes were nanosized (75.74 ± 1 nm), monodisperse (PDI of 0.244 ± 0.014), exhibited high entrapment efficiency (76.66 ± 0.99%), and demonstrated stability with a zeta potential of –32.67 ± 0.38 mV; gel incorporation maintained vesicle integrity. Increasing the gel-base concentration increases viscosity and reduces spreadability. However, 1% carbopol 934 concentration provided the optimal balance, offering the best physicochemical properties, including ideal pH (5.89 ± 0.06), spreadability (6.45 ± 0.06 cm), and viscosity (236770 ± 41.33 cPs), making it most suitable for topical delivery.