Optimal Design of Needle Array for Effective Drug Delivery

Recently, the multi-needle drug injection has been adopted to overcome the shortcomes of conventional single-needle injection, enhancing the efficiency of drug delivery. However, the effect of needle array on the efficacy of drug delivery has not been fully elucidated. In this study, the interactions of drug analogous solution injected from a pair of needles were analyzed to examine the design criteria of effective multi-needle devices for drug delivery. Temporal and spatial variations of relative contents of the solution in the tissues were compared according to the distance between two adjacent needles (DN). As the DN increases from 5 to 20 D, where D is the needle diameter, the solution from each needle encounters 3.5 times faster, and 4.22 times more solution was accumulated. At the same time, the effective spreading area was continuously increased from 54.2 to 177.8 mm2 and RCS gradient decreases from 0.087 to 0.037, due to the overlapping effect of the spreading solution from neighboring needles. Finally, based on the experimental results, an optimal design criterion of needle array for effective drug delivery was proposed. The present results would be helpful in the design of multi-needle injection devices and eventually offer advantage to patients with effective drug delivery.