Enhanced transdermal insulin basal release from silk fibroin (SF) hydrogels via iontophoresis

Abstract

Insulin is the peptide hormone used to treat the diabetes patient. The hormone is normally taken by injection. The transdermal drug delivery system (TDDS) is an alternative route. The silk fibroin (SF) hydrogels were fabricated via solution casting as the insulin matrix. The release and release-permeation experiments of the insulin loaded SF hydrogels were carried out using a modified Franz-diffusion cell at 37 °C for 36 h, under the effects of SF concentrations, pH, and electric field. The release-permeation mechanism through the pig skin was from the Case-II transport with the constant release rate. The diffusion coefficient (D) increased with decreasing SF concentration due to a larger mesh size, and with increasing electric field due to the electroreplusive forces between the insulin and the SF hydrogels against the negatively-charged electrode, and the induced SF hydrogel expansion. The rate and amount of insulin release-permeation became relatively lower as it required a longer time to generate aqueous pathways through the pig skin. The present SF hydrogels are demonstrated here deliver insulin with the required constant release rate, and the suitable amount within a prescribed duration.

Poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as an insulin carrier in silk fibroin hydrogels for transdermal delivery via iontophoresis

“…The T d value of insulin of the insulin-loaded SF hydrogel shied from 299 °C to 278 °C, conrming that insulin was successfully loaded into the SF hydrogel. 38 The thermogram of the insulin-loaded PEDOT:PSS/SF hydrogel, as shown in Fig. 2B(f), shows 4 decomposition stages, which are similar to the thermograms of the insulinloaded PEDOT:PSS and the insulin-loaded SF hydrogel.…”

“…The SF solution was prepared following the procedure previously reported by Sakunpongpitiporn et al, 2022. 38,39 First, 2.0 g of silk cocoon was added into 0.5 g Na 2 CO 3 solution (100 ml) at 100 °C for 30 min to remove sericin. The silk broin precipitate was rinsed with 250 ml DI-water.…”

“…The individual insulin molecules attached to the PEDOT:PSS molecules were released from the SF hydrogel matrix by the possible four mechanisms: the insulin concentration gradient in the initial period; the electro-repulsive force between the cathode and the insulin molecules; the electroosmosis; and lastly, the PEDOT:PSS_3% w/v SF expansion from the electro-repulsive force between the cathode and the SF chains presumably in the later period. 38,47 3.6 Release-permeation behavior 3.6.1 Release kinetics of insulin from PEDOT:PSS/SF hydrogels. The release-permeation proles of insulin under the effects of pH values and electric voltages from insulinloaded PEDOT:PSS_3.0% w/v SF are shown in Fig.…”

Silk Fibroin Microneedles for Transdermal Drug Delivery: Where Do We Stand and How Far Can We Proceed?

“…The most common method of loading drugs with silk fibroin protein is to dissolve or blend the medicine directly into silk fibroin solution. This method is commonly used to prepare films [ 60 ] and hydrogels [ 61 , 62 ]. However, it is necessary to ensure that the structure and activity of the drug will not be affected during the manufacturing process.…”

Silk peptide-hyaluronic acid based nanogels for the enhancement of the topical administration of curcumin

“…In recent years, silk fibroin has attracted great interest due to its biological adhesion and its application in drug stabilization, and is currently used in various drug delivery systems such as nanoparticles, hydrogels and nanofibers ( Chen et al, 2015 ; Sakunpongpitiporn et al, 2022 ; Selvaraj et al, 2022 ). Silk peptide is produced by hydrolysis of silk fibroin.…”