Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

M.S. in Pharmaceutical Science


Pharmaceutics and Drug Delivery

First Advisor

Michael A. Repka

Second Advisor

S. Narasimha Murthy

Third Advisor

Samir A. Ross

Relational Format



The objective of the current study was to investigate the processability of Aquasolve™ HPMC-AS LG via hot-melt extrusion, and to examine the effect of pressurized carbon dioxide (P-CO2) on the physico-mechanical properties of Efavirenz (EFA)-loaded extrudates (EXT). EFA is as a poorly water-soluble drug and HPMC-AS LG was chosen as a carrier for this study. To optimize the process parameters and formulations, various physical mixtures were prepared with the following composition: EFA (30-40-50% w/w) and HPMC-AS LG (70-60-50 % w/w) respectively. Physical mixtures were extruded through the co-rotating twin-screw extruder (16mm Prism Euro Lab, Thermo Fisher Scientific) utilizing a standard screw configuration. P-CO 2 was injected into eight zone of extruder using a high-pressure regulator connected to flexible stainless-steel hose with armor casing. The thermal characterization of extrudates was obtained by using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). A scanning electron microscopy (SEM) was conducted to study morphology and porosity of formulations. The macroscopic morphology changed to a foam-like structure, resulting in increased specific surface area, porosity and dissolution rate. Thus, HPMC-AS LG extrudates with P-CO2 injection exhibited relatively higher dissolution rate than extrudates without P-CO2. Additionally, HPMC-AS LG was able to physically and chemically stabilize the amorphous state of high-loading EFA in the extrudates. The milling efficiency was improved for extrudates with P-CO2 injection due to porous nature and morphology changes.


Emphasis: Pharmaceutics



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.