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

S. Narasimha Murthy

Third Advisor

Eman A. Ashour

Relational Format



ABSTRACTAcute and chronic wounds can be a significant source of pain. In the past, pain associated with chronic wounds has been perceived as an inevitable complication of wound care. Fortunately, recent approaches in wound care have developed strategies to prevent and reduce pain when carrying out wound care. Local anesthetics have been used to that end. Lidocaine is the most widely used topical anesthetic in wound care. However, literature on topical Lidocaine has focused almost exclusively on the clinical application on intact skin. This dissertation aims to advance our understanding of anesthetic wound product formulation and development. Anesthetic wound ointments were prepared by two methods: hot melt extrusion (HME) technology and conventional method. Polyethylene glycol (PEG) polymers with different molecular weights were used as ointment base carriers. Various experiments were conducted to understand the interplay between Lidocaine form, preparation method, and formulation critical attributes. The mechanical properties, in vitro release profile, induced microenvironment pH, and drug content were measured. Finally, the effects of hot-melt extrusion processing and lidocaine selection on pH values and microenvironment were investigated. The results showed a significant correlation between Lidocaine form and the induced microenvironment. Another important finding was that Lidocaine base demonstrated a buffering effect and maintained basic pH throughout all preparations regardless of sample concentration or vehicle pH value. Also, extruded formulations have relatively lower pH values compared to conventional formulations. The results suggest that there is an association between the mechanical properties of anesthetic wound products and the incorporated Lidocaine form. The incorporation of Lidocaine HCl has increased the firmness, consistency, cohesiveness, and work of adhesion of all conventional formulations. Also, the firmness, cohesiveness, and consistency of extruded formulations were significantly different when Lidocaine HCl was incorporated. Finally, the cumulative amount of drug released from Lidocaine HCl formulations was significantly higher compared to Lidocaine base formulations with the same composition. In summary, the results confirmed the significant impact of Lidocaine form on the mechanical and physical properties of anesthetic wound ointments.

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