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In Vitro Characterization Of Simvastatin Loaded Microspheres In The PolyRing Device

Vishwanathan, Anusha

Abstract Details

2008, Master of Science in Engineering, University of Akron, Biomedical Engineering.
Intimal hyperplasia is the most common mechanism of failure for interventional and revascularization procedures like coronary artery bypass grafts (CABG), peripheral artery bypass surgery and dialysis access grafts. It is characterized by the thickening of intima within the artery wall. The reason for the thickening is due to the proliferation of medial vascular smooth muscle cells in the intima of the vessel wall. In a previous study, a novel targeted drug delivery system named the PolyRing was devised, using the drug cyclosporin A (CyA). The objective of our present research was to modify the previously established PolyRing system using the drug simvastatin, a hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor. The research hypotheses were that the loading of simvastatin in the PLGA microspheres could be optimized, and that there was controlled local release of the drug from the PolyRing device over a period of time. In this system, simvastatin was encapsulated within PLGA microspheres, which in turn were entrenched in a PEG block as a polymeric vascular wrap. The microspheres were prepared by an oil-in-water (o/w) emulsion technique. In order to achieve the maximum load, a total of eight runs with various formulation parameters including drug to polymer ratio, surfactant concentration, emulsification time and aqueous volume were conducted. Characterization of the microspheres was then completed to examine the surface morphology, particle size distribution, drug loading, encapsulation efficiency and the device in vitro release behavior. For this study, the null hypothesis was that there were no significant effects of the formulation parameters on encapsulation efficiency. Approximately 100µm size diameter spherical, smooth microspheres were obtained with no appreciable drug loss on the surface. The highest drug loading was observed to be 81.5 ± 6.3 µg drug/mg of microspheres. Only the drug to polymer ratio had significant effect on the encapsulation efficiency with the highest simvastatin encapsulated within the microspheres being 81 ± 9%. In vitro release behavior could not be determined due to the extremely low levels of drug detection in the release medium. Results from a series of experiments performed suggested that there was detection of simvastatin acid, an active metabolite of simvastatin. Alternate means for a suitable detection method have been proposed as future work.
Stephanie Lopina, Ph.D. (Advisor)
Daniel Sheffer, Ph.D. (Committee Member)
Steven Schmidt, Ph.D. (Committee Member)
Michelle Evancho-Chapman, Ms (Committee Member)
79 p.

Recommended Citations

Citations

  • Vishwanathan, A. (2008). In Vitro Characterization Of Simvastatin Loaded Microspheres In The PolyRing Device [Master's thesis, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1205934178

    APA Style (7th edition)

  • Vishwanathan, Anusha. In Vitro Characterization Of Simvastatin Loaded Microspheres In The PolyRing Device. 2008. University of Akron, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1205934178.

    MLA Style (8th edition)

  • Vishwanathan, Anusha. "In Vitro Characterization Of Simvastatin Loaded Microspheres In The PolyRing Device." Master's thesis, University of Akron, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1205934178

    Chicago Manual of Style (17th edition)