Transdermal delivery of human growth hormone via laser-generated micropores.

The epidermal skin barrier plays an important role in protecting underlying structures. It allows the passage of low molecular weight lipophilic molecules, but restricts the passage of hydrophilic molecules and macromolecules. The objective of this study was to investigate the feasibility of transdermal delivery of human growth hormone (hGH) through laser-microporated dermatomed porcine ear skin. The permeation of hGH was evaluated at different laser fluences and micropore densities. In vitro permeation studies were performed on vertical Franz diffusion cells using dermatomed porcine ear skin treated with ablative laser (2940 nm; P.L.E.A.S.E®, Pantec Biosolutions AG). The effect of different fluences (34.1, 45.4, and 68.1 J/cm2) at 10% pore density as well as different densities of micropores (5, 10, and 15%) at fluence of 34.1 J/cm2, on the permeation of hGH was evaluated. After 48 h, 77.12 ± 10.77 μg/cm2 hGH was delivered into the receptor with the application of fluence of 45.4 J/cm2, which was significantly higher than that observed from 34.1 J/cm2 group (53.13 ± 1.75 μg/cm2, p < 0.05). Application of fluence of 68.1 J/cm2 showed permeation of 90.94 ± 3.93 μg/cm2 that was significantly higher than that from 34.1 J/cm2 group (p < 0.05), but not as compared to the 45.4 J/cm2 group (p > 0.05). With the increase in density of micropores from 5 to 15%, permeation of hGH increased significantly from 7.1 ± 2.63 μg/cm2 to 95.89 ± 13.43 μg/cm2 after 48 h (p < 0.05). Thus, overall, the variations in the fluence as well as micropore density of the laser were observed to influence hGH permeation, through laser-microporated dermatomed porcine skin.