Intradermal delivery of vaccine nanoparticles using hollow microneedle array generates enhanced and balanced immune response.

Hollow microneedles can help overcome the skin permeation barrier imposed by the stratum corneum and facilitate transcutaneous delivery of nanoparticle delivery systems. In the present study, we investigated the use of the hollow microneedle array for intradermal delivery of polymeric nanoparticles (NPs) in rats. Compared to intravenous and subcutaneous routes of administration, intradermal delivery of polymeric NPs via a hollow microneedle array resulted in a unique pharmacokinetic profile, characterized by an early burst transit through the draining lymph nodes and a relatively limited overall systemic exposure. Based on high local lymphatic concentrations achieved, we investigated the use of this modality for vaccine delivery. A model antigen ovalbumin (OVA) and TLR agonists imiquimod and monophosphoryl Lipid A encapsulated in poly(d,l-lactide-co-glycolide) (PLGA) NPs were used as the vaccine formulation. Compared to soluble OVA-based vaccine, OVA loaded NPs demonstrated faster antibody affinity maturation kinetics. Moreover, antigen loaded NPs delivered via a hollow microneedle array elicited a significantly higher IgG2a antibody response and higher number of interferon (IFN)-γ secreting lymphocytes, both markers of Th1 response, in comparison to antigen loaded NPs delivered by intramuscular injection and soluble antigen delivered through hollow microneedle array. Overall, our results show that hollow microneedle mediated intradermal delivery of polymeric NPs is a promising approach to improve the effectiveness of vaccine formulations.

Rapid intradermal delivery of liquid formulations using a hollow microstructured array.

PURPOSE: The purpose of this work is to demonstrate rapid intradermal delivery of up to 1.5 mL of formulation using a hollow microneedle delivery device designed for self-application. METHODS: 3M's hollow Microstructured Transdermal System (hMTS) was applied to domestic swine to demonstrate delivery of a variety of formulations including small molecule salts and proteins. Blood samples were collected after delivery and analyzed via HPLC or ELISA to provide a PK profile for the delivered drug. Site evaluations were conducted post delivery to determine skin tolerability. RESULTS: Up to 1.5 mL of formulation was infused into swine at a max rate of approximately 0.25 mL/min. A red blotch, the size of the hMTS array, was observed immediately after patch removal, but had faded so as to be almost indistinguishable 10 min post-patch removal. One-mL deliveries of commercial formulations of naloxone hydrochloride and human growth hormone and a formulation of equine anti-tetanus toxin were completed in swine. With few notable differences, the resulting PK profiles were similar to those achieved following subcutaneous injection of these formulations. CONCLUSIONS: 3M's hMTS can provide rapid, intradermal delivery of 300-1,500 µL of liquid formulations of small molecules salts and proteins, compounds not typically compatible with passive transdermal delivery.