A trilayer microneedle patch for transdermal delivery of the peptide salmon calcitonin for osteoporosis therapy.

Lipid-based nanocarrier systems have multiple advantages, including biocompatibility, biodegradability and drug loading capacity. Combining these findings with the concept of dissolving microneedles (MNs) would aid in the efficient delivery of peptides and improve therapeutic outcomes. Thus, MN-mediated transdermal delivery was explored for the delivery of salmon calcitonin (sCT). The delivery of sCT via MNs is a novel approach with great potential for minimally invasive therapy in chronic osteoporosis patients. This project focused on the transdermal delivery of biomolecular drugs using novel polymeric MN array patch (MAP) systems. Transdermal peptide delivery using lipid-based mixed micellar formulations could provide advantages such as improved stability and enhanced therapeutic efficacy. This work comprises the development and evaluation of dissolving MAPs loaded with Lipoid S 100® based mixed micelles. The physicochemical properties of the micelles were evaluated by loading them into a suitably fabricated and optimized MAP system. The micelle-loaded MAPs were subjected to physicochemical characterization and a 400 μm insertion depth was obtained in Parafilm M® test. Subsequently, ex vivo experiments were conducted in neonatal porcine skin to establish their insertion, dissolution and permeation potential and 42 % sCT was found to permeate in 24 h. The developed MAPs were then analysed in vivo for pharmacokinetics and organ biodistribution in a rat model, where approximately 3-fold rise in relative bioavailability was observed with MAP group. This work highlights the potential of lipid-based mixed micelles loaded MAP systems, especially for the delivery of sensitive peptide molecules such as sCT. The outcome of this research work paves the way for further exploration in this direction.