Document Type


Date of Award

Spring 5-31-2013

Degree Name

Master of Science in Chemical Engineering - (M.S.)


Chemical, Biological and Pharmaceutical Engineering

First Advisor

Costas G. Gogos

Second Advisor

Nicolas Ioannidis

Third Advisor

Ecevit Atalay Bilgili

Fourth Advisor

Piero M. Armenante


The effect of the Active Pharmaceutical Ingredient (API) particle size on the dissolution rate in the polymer excipient during hot melt extrusion is investigated using a co-rotating twin-screw extruder with three different screw configurations. Acetaminophen (APAP) and amphiphilic polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (PVCap-PVAc-PEG) (Soluplus) are chosen as the model API and water- soluble polymer excipient, respectively. APAP is milled using a fluid energy mill (FEM) into two different particle sizes. The thermal properties of processed samples are characterized by TGA and DSC. SEM and optical microscopy are also used in the morphological studies. Under quiescent conditions, API particles with small particle size dissolve faster than the large ones. During the extrusion process using a co-rotating twin- screw extruder, fully-filled kneading blocks perform well in dissolving the API into the polymeric excipient matrices for both of APIs’ particle sizes. However, screws with only conveying elements exhibit only limited ability in dispersing, distributing and melting APIs in the physical mixtures fed into the extruder, resulting in delayed and incompletely dissolution for all the API sizes.