Follicular delivery of a novel peptide therapeutic for the treatment of androgenic alopecia

Abstract

Androgenic alopecia (AGA), commonly known as pattern baldness, along with “loss of hair” following chemotherapy induced alopecia (CIA) are widespread maladies with treatments of little to no effectiveness. Following the discovery of a novel 4.2-kDa peptide’s (murikal/SPR4) ability to markedly increase hair growth when injected intradermally in wild type mice, liposomal topical formulations were developed and optimized to facilitate greater follicular delivery of the therapeutic peptide. Significant enhancement of hair growth rate was seen in mice treated with the peptide and liposomal vehicle when compared to commercial minoxidil (Rogaine®) formulations and peptide alone. An array of lipid formulations and preparation protocols were screened for follicular penetration efficiency utilizing biotinylated or fluor-labeled peptide and confocal microscopy. Two lead formulations were selected for a month long stability study of particle and peptide integrity. Each lead formulation showed near constant retention of encapsulated peptide. Formulation 3 showed a steady profile of ideal particle characteristics, particle size (~300 nm) and zeta potential (~70 mV), over the time period and temperatures tested. The two lead formulations were also applied ex-vivo to donor human scalp skin to determine translatability to a human follicle anatomy. Results of confocal microscopy imaging of treated human tissue were inconclusive on peptide penetration and follicle localization. Further testing is required to demonstrate translatability to human tissues. Overall, these results indicate the clear therapeutic potential of murikal formulated into an optimized liposomal solution for the treatment of AGA and CIA.