István Budai

BGP-15 is an active ingredient with many advantages, e.g., beneficial cardiovascular and anti-inflammatory effects. The transdermal administration of BGP-15 has great potential, which has not been investigated yet, despite the fact that it is a non-invasive and safe form of treatment. The aim of our study was to formulate transdermal patches containing BGP-15 and optimize the production with the Box–Behnken design of experiment. The most optimal formulation was further combined with penetration enhancers to improve bioavailability of the active ingredient, and the in vitro drug release and in vitro permeation of BGP-15 from the patches were investigated. FTIR spectra of BGP-15, the formulations and the components were also studied. The most optimal formulation based on the tested parameters was dried for 24 h, with 67% polyvinyl alcohol (PVA) content and low ethanol content. The selected penetration enhancer excipients were not cytotoxic on HaCaT cells. The FTIR measurements and SEM photography proved the compatibility of the active substance and the vehicle; BGP-15 was present in the polymer matrix in dissolved form. The bioavailability of BGP-15 was most significantly enhanced by the combination of Transcutol and Labrasol. The in vitro permeation study confirmed that the formulated patches successfully enabled the transdermal administration of BGP-15.

The development of oral insulin drug delivery systems is still an ongoing challenge for pharmaceutical technology researchers, as the formulation process has to overcome a number of obstacles due to the adverse characteristics of peptides. The aim of this study was to formulate different sodium-alginate microparticles as a possible method for oral insulin administration. In our previous studies, the method has been successfully optimized using a small model peptide. The incorporation of insulin into alginate carriers containing nonionic surfactants has not been described yet. In order to enhance the absorption of insulin through biological barriers, Labrasol ALF and Labrafil M 2125 CS were selected as permeation-enhancing excipients. They were applied at a concentration of 0.10% (v/v%), along with various combinations of the two, to increase oral bioavailability. Encapsulation efficiency showed sufficient drug incorporation, as it resulted in over 80% in each composition. In vitro dissolution and enzymatic stability test results proved that, as a pH-responsive polymer, alginate bead swelling and drug release occur at higher pH, thus protecting insulin against the harsh environment of the gastrointestinal tract. The remaining insulin content was 66% due to SIF degradation after 120 min. Permeability experiments revealed the impact of permeation enhancers and natural polymers on drug absorption, as they enhanced drug transport significantly through Caco-2 cells in the case of alginate microparticle formulations, as opposed to the control insulin solution. These results suggest that these formulations are able to improve the oral bioavailability of insulin.