Promoting effects of chemical permeation enhancers on insulin permeation across TR146 cell model of buccal epitheliumin vitro

Abstract

To find potential enhancers for facilitating the buccal delivery of insulin, a TR146 cell-culture model of buccal epithelium, cultured on commercially available insert plates, was used to evaluate the permeability-enhancing effects of several traditional and new types of chemical enhancers, including N-acetyl-L-cysteine (NAC), sodium deoxycholate (SDC), sodium nitroprusside (SNP), reduced glutathione (GSH), glutamine (Gln), chitosan (CS), L-arginine (Arg), 1-dodecylazacycloheptan-2-one (Azone), and soybean lecithin (SPC) (50 and 10 μg/mL respectively). Permeability studies were performed to determine the enhancing effects of these compounds on insulin permeation across the cell-culture model. The enhancing effects of the enhancers were assessed by calculating the apparent permeability coefficients and enhancement ratio. Cytotoxicity of the permeation enhancers at different concentrations was investigated by using the methylthiazolydiphenyl-tetrazolium bromide (MTT) assay. Results showed that 50 μg/mL of NAC, SDC, GSH, CS, Arg, Azone, SPC, SNP, and 10 μg/mL of SNP had a significant enhancing effect on promoting the transport of insulin across the TR146 cell model. MTT assays showed that 50 μg/mL of Gln, Azone, SDC, SNP, Arg, 10 μg/mL SDC, and Arg had obvious toxic effects on TR146 cells. Therefore, NAC, GSH, CS, SPC, and SNP appear to be safe, effective permeability enhancers that promote the transport of insulin across the TR146 cell-culture model of buccal epithelium and may be potential enhancers for buccal delivery of insulin with both low toxicity and high efficiency.

Pre-formulation and systematic evaluation of amino acid assisted permeability of insulin across in vitro buccal cell layers

“…S3. TEER results showed the formation of a stable stratified layer between days 28 to 29 which were used for experiments, as reported by other authors21.…”

“…The TEER results for arginine exhibited no significant reduction in TEER values across all concentrations of arginine used. Thus, cell layer integrity can be said to have been maintained throughout the 4 hours of the permeability experiment112133. Elshaer11 reported similar findings where high concentrations of arginine did not significantly affect the TEER measurements before and after permeability studies using Caco-2 cells.…”

“…HBSS also enabled the circumvention of the potential toxicity related to solubilising insulin in 0.01N HCl prior to permeation experiments as reported by other authors2122. For HBSS solubility studies, a range of ionisable amino acids was utilised, their physicochemical properties are presented in Supplementary Table S1.…”

Amino-Terminated Generation 2 Poly(amidoamine) Dendrimer as a Potential Broad-Spectrum, Nonresistance-Inducing Antibacterial Agent

“…(a) MTT assay The cytotoxicity of G1.0, G2.0, G3.0, and G4.0 PAMAM-NH 2 to the human gastric epithelial cell line GES-1 was determined by a standard MTT assay (24,25). Briefly, cells were maintained in DMEM media with 10% fetal bovine serum (FBS) and 30 μg/mL gentamicin.…”

A potent and selective antimicrobial poly(amidoamine) dendrimer conjugate with LED209 targeting QseC receptor to inhibit the virulence genes of gram negative bacteria

“…23 Briefly, cells were maintained in DMEM medium with 10% FBS and 30 μg/mL gentamicin. Cells (5.0 × 10 3 /well) were grown for 24 or 48 hours at 37°C to confluence in 96-well plates.…”