Hollow Microneedle for Drug Delivery Applications to Improve Patient Compliance

Abstract

In recent years, microfluidic Drug Delivery System (DDS) using microneedle have been given much attention as a novel way for transdermal drug delivery. In this paper, the orthogonal array design is applied for the first time to optimize the bevel tip hollow microneedle suitable for efficient transdermal drug delivery applications. An analytical model has been presented considering the puncture force and friction forces acting on the microneedle during insertion into the soft tissue. The stiffness coefficients are derived as a function of the internal behaviour of the microneedle. Based on these outcomes, an L16 orthogonal Taguchi experiment with two factors, each having four levels, has been utilized to determine the optimal microneedle tip angle (α0) and insertion force (F) for successful penetration of microneedle into the soft tissue during drug delivery. The output responses accounted for investigation are the stiffness coefficients, forces and moments acting on the microneedle, deflection, strain and contact stress. These output response variables must be optimal to avoid failure of microneedle and their effects are studied using Analysis of Variance (ANOVA) to determine the relationship between the levels and the responses. The Taguchi experiment performed using Signal-to-Noise Ratio suggests that microneedle tip angle of 10o and insertion force of 0.25N is optimal. The microneedle tip angle is found to be the most significant control factor for the robust design of hollow microneedle to obtain successful insertion of microneedle into the soft tissue during drug delivery applications.