DEVELOPMENT OF DISSOLVING POLYMERIC MICRONEEDLES AS AN APPLICATOR FOR OCULAR DRUG DELIVERY SYSTEM

Abstract

Dissolving polymeric microneedles are micron scale technology and very attractive for minimally invasive intraocular tissue. The application and development of dissolving polymeric microneedles by using biodegradable polymer has been explored as a novel physical method for ocular drug delivery. The purpose of this study was to investigate the appropriate polymer for fabrication of the dissolving polymeric microneedles as an applicator for ocular drug delivery system. The microneedles were fabricated by micro-molding technique using hydroxypropyl methylcellulose (HPMC) mixed with polyvinylpyrrolidone K30 (PVP K30) in various concentrations: C1 (10%HPMC), C2 (10%HPMC:10%PVP K30), C3 (10%HPMC:15%PVP K30) and C4 (10%HPMC:20%PVP K30). The physical appearance under microscope, mechanical strength by texture analyzer, and dissolution study by measuring the microneedle height inserting in the ocular tissues at predetermined time were evaluated. All formulations could produce microneedle arrays (11 rowsx11 columns) with 10 mm² of microneedle patch area and conical shape needle. The height and base diameter of microneedle were 530 ± 25 μm and 300 ± 3 μm, respectively.  The change of percent needle height of C1, C2, C3 and C4 in the mechanical strength (bending force and fracture force; 1.8, 2.8, 3.8, 5.8 and 8.8 N) showed that formulations were added 15% and 20%PVP K30 changing percent needle height significantly less than C1 and C2. However, some needle of C4 could be fractured since 5.8 N. The dissolution result showed that dissolving polymeric microneedles were completely dissolved within 180 seconds. In conclusion, the fabrication of dissolving polymeric microneedles by mixing HPMC and PVP K30 polymer in the appropriate ratio provided the suitable microneedle properties for ocular drug delivery.