Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

M.S. in Pharmaceutical Science

First Advisor

Michael A. Repka

Second Advisor

Walter G. Chambliss

Third Advisor

Eman Ashour


University of Mississippi

Relational Format



The aim of the current study was to prepare and compare acyclovir (ACV) floating gastro-retentive formulations synthesized via hot-melt extrusion (HME) techniques using P-CO2 and sodium bicarbonate. Physical mixtures of ACV (20%, w/w) and HPC EF (70%, 60%, w/w) with HPC MF (10%, w/w) or HPMCAS-LG (10%, w/w) were prepared using a co-rotating twin-screw extruder with a screw configuration shoin Figure 2. P-CO2 was injected into zone 9 of the extruder or NaHCO3 was added (10% w/w) during the extrusion process. In vitro dissolution studies (0.1 N hydrochloric acid medium) demonstrated that the formulations floated on the medium because of their porosity and low density. Formulations with NaHCO3 (F9, F10) shobetter extended release potential than the counterparts with P-CO2 (F7, F8). The in vitro drug release mechanism of the optimized formulation was found to best fit with the first-order (R2=0.9686) and Higuchi models (R2=0.9614). Accelerated stability studies demonstrated similar release profiles between fresh samples and stability samples after 3 months storage. Altogether, the ACV floating gastro-retentive formulations were successfully developed, which can prolong the gastric residence time to extend therapeutic effects.



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