(51h) Zeolite Microneedle: Design for Drug Delivery

The most common routes for drug delivery are by oral administration, hypodermic injection and transdermal delivery. For transdermal delivery, the rigid stratum corneum is an effective barrier against the effective delivery of drugs. Different innovative strategies were developed to breach this barrier including iontophoresis, phonophoresis, skin ablation using chemicals, laser or radiofrequency and microneedle. Microneedle offers a simple, painless and less invasive transdermal delivery of drug that can be inexpensively manufactured and implemented. Unlike hypodermic injection, less medical wastes are produced and it poses a smaller risk for disease transmission.

This work presents for the first time the use of porous zeolite as material for microneedle for use in drug delivery. The study includes the fabrication of zeolite microneedle, mechanical properties of zeolite microneedles and its use for transdermal delivery of insulin and influenza vaccine in rodents (i.e. rats and mice animal models). Pure silica zeolite that has similar chemical composition as glass but porous, was grown on needle template to create an array of free standing hollow zeolite microneedles. The needle lumen and length were designed for efficient drug delivery, while maintaining good mechanical strength for skin insertion. The zeolite growth conditions were adjusted to obtain different inter- and intra-crystalline pore size for controlled drug delivery and strength that has a high safety margin comparable to metal microneedles.

The zeolite microneedles did not cause noticeable skin irritation or redness during their use in the animal study. The in vitro and in vivo studies of insulin delivery using zeolite microneedles were carried out. The blood glucose and insulin levels in diabetic rats were monitored during the insulin study for the in vivo study. Influenza vaccination using zeolite microneedle was done on mice, and the IgG level in blood serum was measured to determine the effectiveness of microneedles for vaccination.