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Speaker at Drug Delivery Events - Shereen M. Assaf
Jordan University of Science and Technology, Jordan
Title : Design and assessment of transdermal delivery system containing Levodopa-Loaded Nanoparticles


Levodopa, an essential precursor of dopamine, was widely used to address motor disorders in the early stages of Parkinson's disease. However, its effectiveness was hindered by a short plasma half-life, enzymatic conversion in the systemic circulation, limited absorption in the upper small intestine, and difficulties in swallowing, particularly common in Parkinson's patients. To overcome these challenges, transdermal delivery of levodopa was explored in this study. The research focused on formulating and characterizing levodopa-chitosan nanoparticles and subsequent integration into transdermal patches. Ionic gelation was employed to prepare the nanoparticles, and their essential attributes, including particle size, zeta potential, encapsulation efficiency, and loading capacity, were evaluated. The transdermal patches were crafted using a film casting technique, incorporating Eudragit® RL as the drug reservoir and ethylene-vinyl acetate as the backing layer. The patches underwent thorough assessment for thickness, weight, drug content, flexibility, drug release, and permeation. Further analyses involved Fourier transform infrared spectral analysis, differential scanning calorimetry analysis, thermogravimetric analysis, and X-ray diffraction for both the nanoparticles and patches. Scanning electron microscopy was employed to observe the morphology of the nanoparticles and their uniform distribution within the polymeric film. A chitosan to tripolyphosphate weight ratio of 3:1 was identified as optimal for subsequent analyses and transdermal preparation. The selected nanoparticles exhibited favorable characteristics, with a size of 141.44 nm, a polydispersity index of 0.29, a zeta potential of 27.30 mV, an encapsulation efficiency of 49.21%, and a loading capacity of 20.40%. The patches, assessed for thickness, weight, and drug content, demonstrated the reproducibility of the solvent casting method. Physicochemical characterization confirmed the absence of interaction between the nanoparticles and Eudragit® RL, and SEM images validated the uniform distribution of nanoparticles in the polymeric film. In vitro permeation studies revealed that nanoparticles enhanced the drug permeation, and patches loaded with nanoparticles exhibited significantly higher permeability than those with pure drug. Notably, the transdermal patches demonstrated prolonged drug permeation compared to free nanoparticles, offering potential advantages in reducing the frequency of applications and enhancing patient compliance.

Audience Take Away Notes:

  • This study addresses challenges in transdermal drug delivery, discussing how they were addressed and overcome

  • The findings could spark new research on levodopa-loaded nanoparticles for targeted brain delivery, potentially eliminating the need for combining therapy with carbidopa

  • Valuable for researchers in nanotechnology or transdermal drug delivery, this work offers practical solutions to common issues

  • Interesting discoveries in this study suggest promising avenues for future research

  • The work outlines a systematic design and approach to optimize the properties of levodopa-loaded nanoparticles and their skin delivery


Dr. Shereen M. Assaf is a distinguished pharmaceutical sciences professor. After receiving her PhD from the University of Strathclyde, Glasgow, in 1992, she joined the faculty of pharmacy at Jordan University of Science and Technology. She has nine years of administrative experience and extensive contributions to academia. She is also a consultant and committee member at the Jordanian Food and Drug Administration since 2012. Her research focuses on designing pharmaceutical dosage forms, specializing in microencapsulation, nanocarriers, liposomes, and polymeric drug delivery systems across various administration routes.