Track: Formulation and Delivery - Chemical - Drug Delivery - Other Routes of Administration - Transdermal and Topical
Category: Poster Abstract
Development of Lysozyme Loaded Microneedles for Dermal Applications
Purpose: Microneedles are being explored for the delivery of macromolecules such as proteins and peptides through a painless disruption of the major barrier of the skin. Microneedles could be engineered and fabricated to encapsulate and enable a bolus or a sustained release on insertion into the skin. Lysozyme is naturally occurring enzymes (14 kDa) having antibacterial activity. Microneedles have the capability and the advantage of entrapping lysozyme within a polymeric matrix using fabrication procedures that do not alter the protein integrity, enable a bolus, or a sustained release. Methods: Polymeric microneedles were fabricated to entrap 100 µg lysozyme using biodegradable polymers such as 50 % w/v Hyaluronic acid (HA) and 1% w/v polylactic co glycolic acid (PLGA). Microneedles were characterized using scanning electron microscopy and texture analysis for their geometry and mechanical properties. The structural integrity of lysozyme entrapped microneedles was observed using circular dichroism and SDS-page analysis. The microneedles were subjected to stability studies for understanding the structural stability of proteins in polymeric microneedles. The biological efficacy of lysozyme in microneedles was evaluated using dose-dependent enzymatic activity. Results: Lysozyme loaded microneedles using HA showed a release of 57± 1.21% release within an initial 15 minutes enabling an immediate release profile. Microneedles fabricated using PLGA showed a release of 28 ± 2.35 % at the end of 72 hours implying a sustained release profile. The lysozyme loaded microneedles were characterized using Circular Dichroism wherein the spectra displayed a strong negative band in the range 200 -280 nm, with signal intensity greater at 208 nm than at 220 nm, which is a characteristic feature of a + b protein. Similarly, SDS-PAGE analysis performed for lysozyme loaded microneedles and native lysozyme, under reducing conditions exhibited strong bands of lysozyme monomer (around 14 kDa) implying that the structural integrity of lysozyme was maintained in the microneedles and the fabrication procedure had no impact lysozyme structure. The enzymatic assay showed a dose-dependent lysis wherein 100 ± 1.73 µg lysozyme entrapped inside microneedles was biologically active indicating that MNs can cause bacterial cell lysis for dermal applications. Conclusion: Our studies showed that microneedles have the capability and the advantage of encapsulating lysozyme within a polymeric matrix using fabrication procedures that enable either an immediate or a sustained release. However, further studies are required to investigate the feasibility of using this platform to deliver active therapeutic proteins for dermal applications in wounds and skin infections.