Electronic Theses and Dissertations

Date of Award


Document Type


Degree Name

Ph.D. in Pharmaceutical Sciences


Pharmaceutics and Drug Delivery

First Advisor

Michael A. Repka

Second Advisor

Jo Seongbong

Third Advisor

S. Narasimha Murthy

Relational Format



Due to preferential site of drug absorption and the need for increased concentration of medication at the required tissues, dosage forms should be designed or formulated in such a way that medication is released at a specific site or after a specific time in the gastrointestinal tract (GIT). Knowledge of transit times of dosage forms in each part of GIT, by use of particular polymers or employing specific delivery systems such as floating systems, delivery of medication to specific sites in the GIT can be achieved. HME coupled FDM 3D printing has the capability to create customized dosage forms for personalized pharmacotherapy with its ability to produce dosage forms with complex structures, customized shapes, and sizes. Chronotherapy deals with synchronizing drug delivery with the body’s circadian rhythm to optimize therapeutic efficacy and minimize side effects. Using the advantage of pH-dependent solubility of Eudragit S100 (ES100) (as an enteric polymer that solubilizes and releases the drug at above pH 7), a chronotherapeutic drug delivery system for KTP and IBU was successfully developed for the treatment of arthritis conditions in the early morning hours. The drug release studies conducted in different media showed the desired lag time and release characteristics. Maintaining a constant plasma drug concentration is not beneficial in all disease conditions. Some diseases may require pulse delivery of drugs to avoid unwanted adverse effects and drug exposure. Various biological factors influence the transit time of drugs in the upper gastrointestinal tract and possess a challenge to the drugs that are locally active in the stomach, unstable at a high pH, or poorly soluble in the lower parts of the gastrointestinal tract. To overcome these issues, a floating pulsatile system was developed which showed a high potential to deliver drugs that need high residence time in the stomach and the pulsatile release of theophylline. Quality by design (QbD) is defined as a systematic approach to development that begins with predefined objectives and emphasizes product and process understanding based on sound science and quality risk management. QbD is combined with FDM 3D printing to develop personalized dosage forms for patient-centric pharmacotherapy.



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