Influence of lipids on the mannitol flux during transdermal iontophoresis in vitro

The role of nitric oxide (NO) in restitution was examined in intact sheets of in vitro guinea pig gastric mucosae after mucosal injury induced by exposure of the luminal surface to 1.25 M NaCl for 10 min. The recovery of transmucosal electrical resistance and [3H]mannitol flux after the injury were significantly greater at luminal pH (pH1) 7.0 than 3.0. The recovery was abolished by pretreatment with 1 mM NG-nitro-L-arginine methyl ester (L-NAME), only at pHL 3.0, an effect reversed by 1 mM L-arginine. Enhancement of the recovery by L-arginine at pHL 3.0 was abolished by 50 microM methylene blue (MB), an effect restored by 1 mM N6,2'-O-dibutyryl guanosine 3',5'-cyclic monophosphate (DBcGMP). In L-arginine- but not L-NAME-treated tissues, recovery was enhanced further by an increase in serosal [HCO3-] and was inhibited by 5% N-acetyl-L-cysteine in the luminal solution or by the removal of serosal HCO3-. Morphological examination showed the formation of a thick "mucoid cap" in L-arginine-but not L-NAME-treated tissues. These results suggest that, in the presence of luminal acid, endogenous NO contributes to restitution in injured gastric mucosa at least in part by facilitating the formation of the mucoid cap.

Download Full-text

The role of electroosmotic flow on in-vitro transdermal iontophoresis

Journal of Controlled Release ◽

10.1016/s0168-3659(96)01468-x ◽

1997 ◽

Vol 43 (1) ◽

pp. 23-33 ◽

Cited By ~ 14

Author(s):

Ruey-Yih Lin ◽

Yih-Chien Ou ◽

Wen-Yih Chen

Keyword(s):

Electroosmotic Flow ◽

Transdermal Iontophoresis

Download Full-text

Controlled Transdermal Iontophoresis of Insulin from Water-Soluble Polypyrrole Nanoparticles: An In Vitro Study

International Journal of Molecular Sciences ◽

10.3390/ijms222212479 ◽

2021 ◽

Vol 22 (22) ◽

pp. 12479

Author(s):

Kamran Tari ◽

Soroush Khamoushian ◽

Tayyebeh Madrakian ◽

Abbas Afkhami ◽

Marek Jan Łos ◽

...

Keyword(s):

Sodium Dodecyl ◽

Chloride Concentration ◽

In Vitro Study ◽

Water Soluble ◽

Drug Permeation ◽

Dodecyl Sulfate ◽

Potential Applicability ◽

Polypyrrole Nanoparticles ◽

Transdermal Iontophoresis

The iontophoresis delivery of insulin (INS) remains a serious challenge due to the low permeability of the drug through the skin. This work aims to investigate the potential of water-soluble polypyrrole nanoparticles (WS-PPyNPs) as a drug donor matrix for controlled transdermal iontophoresis of INS. WS-PPyNPs have been prepared via a simple chemical polymerization in the presence of sodium dodecyl sulfate (SDS) as both dopant and the stabilizing agent. The synthesis of the soluble polymer was characterized using field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), fluorescence spectroscopy, and Fourier transform infrared (FT–IR) spectroscopy. The loading mechanism of INS onto the WS-PPyNPs is based on the fact that the drug molecules can be replaced with doped dodecyl sulfate. A two-compartment Franz-type diffusion cell was employed to study the effect of current density, formulation pH, INS concentration, and sodium chloride concentration on anodal iontophoresis (AIP) and cathodal iontophoresis (CIP) of INS across the rat skin. Both AIP and CIP delivery of INS using WS-PPyNPs were significantly increased compared to passive delivery. Furthermore, while the AIP experiment (60 min at 0.13 mA cm–2) show low cumulative drug permeation for INS (about 20.48 µg cm−2); the CIP stimulation exhibited a cumulative drug permeation of 68.29 µg cm−2. This improvement is due to the separation of positively charged WS-PPyNPs and negatively charged INS that has occurred in the presence of cathodal stimulation. The obtained results confirm the potential applicability of WS-PPyNPs as an effective approach in the development of controlled transdermal iontophoresis of INS.

Download Full-text