Development and Characterization of Sucralfate-Loaded Liposomes for Topical Delivery: Physicochemical Characterization, Sustained Release and In-Vitro Antibacterial Evaluation

Abstract

Background: Sucralfate is widely used for its protective and therapeutic effects; however, its physicochemical properties can present challenges for formulation development. Liposomal drug delivery provides an approach for incorporating therapeutic agents into vesicular carriers and modifying their release and delivery characteristics.

Objective: The present study aimed to develop and characterize Sucralfate-loaded liposomes and to evaluate the optimized formulation for physicochemical properties, entrapment efficiency, in-vitro drug release, topical cream characteristics, and antibacterial activity.

Methods: Sucralfate was subjected to preformulation studies including organoleptic evaluation, solubility analysis, pH determination, melting-point analysis, UV spectrophotometric analysis and Fourier-transform infrared spectroscopy (FTIR). Five liposomal formulations (F1-F5) containing different ratios of soya lecithin and cholesterol were prepared by the thin-film hydration method. The formulations were evaluated for physical appearance, particle size, zeta potential and entrapment efficiency. The optimized formulation was further examined by scanning electron microscopy (SEM), incorporated into a topical cream base, and evaluated for appearance, viscosity, pH and spreadability. In-vitro drug release was investigated using a Franz diffusion cell, and the release data were fitted to different kinetic models. Antibacterial activity was assessed by the agar well-diffusion method against Escherichia coli.

Results: Sucralfate appeared as a white to off-white, odourless fine powder and showed poor solubility in water and phosphate buffer pH 7.4. The observed melting point was 220.17°C and the λmax was 288 nm. The calibration curve over 2-12 µg/mL demonstrated a linear relationship, with an R² value of 0.9998. Among the five formulations, F1 exhibited the smallest particle size (290.6 nm), highest negative zeta potential (-41.4 mV), and highest entrapment efficiency (93.48%). SEM examination demonstrated predominantly spherical nanosized vesicular structures. The optimized liposomal cream showed a smooth and homogeneous appearance, viscosity of 1694 cps, pH 6.5 and spreadability of 17.45 g·cm/s. The formulation exhibited progressive drug release, reaching 90.63% at 12 h. Among the evaluated kinetic models, the present work data reported the highest correlation for the zero-order model (R² = 0.980). In the antibacterial study, F1 produced a zone of inhibition of 11.23 mm against E. coli, compared with 5.61 mm for free Sucralfate and 0 mm for the control.