Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

M.S. in Pharmaceutical Science


Pharmaceutics and Drug Delivery

First Advisor

Micheal A Repka

Second Advisor

S. Narasimha Murthy

Third Advisor

Samir A. Ross


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.