Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

Ph.D. in Pharmaceutical Sciences

First Advisor

Michael A. Repka

Second Advisor

Michael A. Repka

Third Advisor

Eman Ashour


University of Mississippi

Relational Format



Implants are drug delivery platforms that consist of a drug-polymer matrix with the ability of providing a localized and efficient controlled release of the drug with minimal side effects and achievement of the desired therapeutic outcomes with low drug loadings. Direct powder extrusion (DPE) 3D printing technology involves the extrusion of material through a nozzle of the printer in the form of pellets or powder. Project one involved the preparation of novel polycaprolactone/polyethylene glycol-based raloxifene hydrochloride subdermal solid cylindrical implants using a single-step hot-melt extrusion (HME) continuous process, for the provision of a sustained and prolonged release of RX-HCl, providing clinical advantage over the oral dosage forms of raloxifene hydrochloride. The 11-mm co-rotating twin-screw extruder was used to prepare the implants. The prepared cylindrical-shaped solid implants with dimensions of 10 mm (length) by 2 mm (diameter) were characterized by DSC, PXRD, FTIR, SEM, and in vitro dissolution analysis. Project two was focused on investigating the use of the CELLINK BIO X™ bioprinter using DPE 3D printing technique to fabricate and evaluate the impact of different shapes (cuboid, cylinder, and tube) of raloxifene hydrochloride (RFH)-loaded subdermal implants on the release of RFH from the implants. Project three was aimed at evaluating the impact of different processing techniques, viz., hot-melt extrusion (HME) technology vs. DPE 3D printing technique, on the release of RFH from the implants fabricated by each processing technique. All the fabricated implants were characterized by XRD, DSC, SEM, and FTIR, and evaluated for their water uptake, mass loss, and in vitro RFH release. The current projects successfully demonstrated a great opportunity of controlling and/or tuning the release of RFH from the subdermal implants by altering the implant shape, and hence surface are, and could be a great contribution and/or addition to the personalization of medicines and improvement of patient compliance.



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