Tracking the Effect of Phosvitin (PV) Concentration on the Skin Permeation of Somatotropin (STH) from Semi-Solid Hydrogel Formulations

Recombinant human growth hormone (rhGH) is utilized in pediatric patients with short stature for a variety of indications, including those in which the primary growth defect is not related to growth hormone deficiency (GHD). However, due to the instability of the hormone in the gastrointestinal tract and its short half-life, an alternative route of administration is being sought, which may be the skin. One strategy to extend the half-life of proteins involves the use of biodegradable polymeric matrices for transdermal drug delivery systems. While hydrogels are recognized for their high stability, the transport of proteins through the skin may be hindered. To address this, the use of active carriers is being investigated to enhance the efficiency of protein permeation through the skin. In this study, an effort was made to optimize the concentration of phosphitin (PV) as a carrier for somatotropin (STH). PV is a protein that possesses a distinctive cation chelating capability and amphiphilic character. As the concentration of PV increased, the rate of its emulsifying activity increased concomitantly. Methylcellulose (MC) was used as the hydrogel matrix. The study investigated three distinct concentrations of PV to ascertain the most optimal concentration to enhance STH availability. Following the formulation of hydrogel compositions containing STH and PV, the permeation process through porcine skin was examined using Franz's chambers. The findings revealed that the incorporation of PV significantly impacted both the penetration time of STH and the extent of STH penetration. Subsequently, an extensive evaluation of the physicochemical parameters of the formulations, encompassing pH, rheological, and textural properties, was conducted to assess their suitability for skin application. This evaluation aimed to ensure not only adequate persistence time of the formulation on the skin surface but also formulation stability and persistence of the active substance (STH).