Diabetes mellitus poses a major public-health burden. Both in the United States and throughout the world, progressive increases have been observed in the prevalence of both Type 1 diabetes mellitus (T1DM) and Type 2 diabetes (T2DM). This application focuses on the development of thermodynamically stable insulin analogs that may be applied to novel drug-delivery systems. The applicant is an MSTP student who seeks training in biochemistry toward a future career that integrates clinical care with the development of novel therapeutics and devices. Clinical insulin regimens must compensate for the loss of regulated secretion by careful dosing coordinated with the patient's food intake, level of activity, and results of serial glucose monitoring. Adherence to such regimens requires self-injections several times a day. Such delivery methods not only cause discomfort for the patient, but they are also difficult to maintain in terms of timing and accurate administration of doses. The safety and efficacy of current regimens may be enhanced through the development of alternative mechanisms for insulin administration. Insulin's nature as a peptide hormone that is susceptible to chemical and temperature-induced degradation is a major barrier for its implementation in novel delivery systems. This application describes the combination of two previously characterized stabilizing modifications of the insulin hormone that will be used to create heat-stable insulin analogs that can be fabricated into PLGA- polymeric matrices and retain their biological activity. These insulin-infused polymers will be developed into microneedle implants that will serve as basal insulin delivery systems. These implants will reduce the frequency of self-injection while delivering safe, consistent, and continuous doses of insulin. Because of the interdisciplinary nature of the proposed studies, laboratory mentorship by the primary Thesis Advisor (M. Weiss, M.D., Ph.D.; Professor of Biochemistry, Biomedical Engineering & Medicine) will be complemented by a master clinician (diabetologist F. Ismail-Beigi, Professor of Medicine), an X-ray crystallography expert (V. Yee; Associate Professor of Biochemistry), and materials-scientist specializing in macromolecular sciences (J. Pokorski; Professor of Macromolecular Sciences). Additionally, consulting advisors D. Anderson and R. Langer, protein engineers at the Massachusetts Institute of Technology, will provide additional guidance on the development of the project.
Since its advent in 1922, insulin replacement therapy has led to dramatic improvement in health and life span among patients with Type 1 diabetes mellitus (T1DM) and among a subset of patients with Type 2 diabetes (T2DM). Despite the development of insulin analogs with modified pharmacokinetic properties, adherence to insulin regimens (and thus glycemic control) remains difficult for patients, particularly because administration of the protein requires self-injection. A major barrier to the development of alternative delivery mechanisms has been the chemical and temperature-induced degradation of the insulin hormone. In this project we seek to develop ultra-stable insulin analogs (stable through a 95-120oC polymer manufacturing process) that may be used in a novel class of topical polymer-matrix delivery systems (dissolvable microneedle patches); the ready removability of such patches promises to enhance safety by minimizing the amount of insulin actually in the subcutaneous depot and so reducing the risk of hypoglycemia.
