Microneedles: bench to bedside.

Microneedles are tiny micron-sized structures, made of a variety of materials, used to minimally disrupt the outermost layer of the skin for enhancing the delivery of therapeutic molecules across the skin. They are sufficiently long enough just to breach the stratum corneum barrier but too short to reach the nerve endings that perceive pain. Treating the skin using microneedles results in the creation of aqueous microchannels that promote delivery of molecules practically of any size.

Effect of lipophilicity on microneedle-mediated iontophoretic transdermal delivery across human skin in vitro.

The effect of lipophilicity of drug on the microneedle (MN)-mediated iontophoretic delivery across dermatomed human skin was studied. Beta blockers with similar pKa but varied log P values were selected as model drugs in this study. Iontophoresis (ITP) or MNs, when used independently, increased the transdermal flux of beta blockers as compared with passive delivery (PD).

Microneedle assisted iontophoretic transdermal delivery of prochlorperazine edisylate.

This paper investigates the microneedle (MN) mediated in vitro transdermal iontophoretic delivery of prochlorperazine edisylate (PE) across dermatomed human skin. The Dermaroller™ induced microchannels were visualized using methylene blue staining and scanning electron microscopy. In vitro skin permeation studies were performed using vertical static Franz diffusion cells.

Characterization of microchannels created by metal microneedles: formation and closure.

Transdermal delivery of therapeutic agents for cosmetic therapy is limited to small and lipophilic molecules by the stratum corneum barrier. Microneedle technology overcomes this barrier and offers a minimally invasive and painless route of administration. DermaRoller(®), a commercially available handheld device, has metal microneedles embedded on its surface which offers a means of microporation.

Transdermal iontophoretic delivery of selegiline hydrochloride, in vitro.

Transdermal iontophoretic delivery of selegiline hydrochloride (SH) across dermatomed human skin was studied. Electrochemical stability and various factors affecting the skin permeation were investigated. SH was stable under the influence of an electrical field.

In vitro transdermal delivery of therapeutic antibodies using maltose microneedles.

This paper investigates the microneedle-mediated in vitro transdermal delivery of human IgG as a model protein and demonstrates its applicability to deliver a monoclonal antibody. Microchannels created by the treatment of maltose microneedles in full thickness hairless rat skin were visualized using methylene blue staining. Cryostat sections were prepared and stained using hematoxylin and eosin to locate the depth of penetration.

Characterization of solid maltose microneedles and their use for transdermal delivery.

Purpose: To characterize solid maltose microneedles and assess their ability to increase transdermal drug delivery.

Materials And Methods: Microneedles and microchannels were characterized using methylene blue staining and scanning electron microscopy. Diffusion pattern of calcein was observed using confocal scanning laser microscopy.