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

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.

The bioavailability of cytarabine in dogs with meningoencephalitis of unknown etiology through iontophoresis and rectal delivery

Background: Cytarabine (CA) is used to treat dogs with meningoencephalitis of unknown etiology (MUE) by subcutaneous or intravenous administration. Aim: The objective was to investigate transdermal iontophoresis and rectal administration as alternative routes of CA delivery. Methods: Two client-owned dogs with MUE were studied. The ActivaPatch® IONTOGOTM 12.0 iontophoresis drug delivery system delivered 200 mg/m2 CA transdermally. Blood samples were collected by sparse sampling technique after initiation of the device. At another visit, 100 mg/m2 CA was administered rectally. Blood samples were collected by sparse sampling technique after administration. Plasma CA concentrations were measured by high-pressure liquid chromatography. Results: The concentration of plasma CA after transdermal and rectal administration was below the limits of quantification (0.1 μg/ml) in all samples suggesting inadequate bioavailability with transdermal and rectal administration. Conclusion: Transdermal and rectal CA administration are not reasonable alternative routes of delivery.

Local inhibition of carbonic anhydrase does not decrease sweat rate

Background: The purpose of this study was to measure sweat rate during exercise in the heat after directly inhibiting carbonic anhydrase (CA) in eccrine sweat glands via transdermal iontophoresis of acetazolamide. It was hypothesized that if CA was important for sweat production, local administration of acetazolamide, without the confounding systemic effects of dehydration typically associated with past studies, would have a significant effect on sweat rate during exercise. Methods: Ten healthy subjects volunteered to exercise in the heat following acetazolamide or distilled water iontophoresis on the forearm. Results: The distilled water iontophoresis site had a mean sweat rate during exercise in the heat of 0.59±0.31 μL/cm2/min, while the acetazolamide iontophoresis site had a mean sweat rate of 0.63±0.36 μL/cm2/min (p>0.05). Conclusions: The most important finding of the current study was that iontophoresis of acetazolamide did not significantly decrease sweat rate during exercise in the heat. Such results suggest that in past studies it was systemic dehydration, and not CA inhibition at the level of the sweat gland, that caused the reported decreased sweat rate.

Transdermal Iontophoresis on Gerhardt-Mitchell's Disease of Joints - A rear case report

Gerhardt-Mitchell's disease which is also named as Erythromelalgia is an unusual neurovascular pain syndrome which features with group of three characteristics i.e., raise in temperature, red color pigmentation of skin and pain with a quality of burning. All three characteristics are most importantly seen in the extremities. Erythromelalgia may occur either as a primary or secondary disorder. Clinical presentation of primary erythromelalgia is linked with severe burning pain, pronounced erythemaof the skin, swelling and increased skin temperature, specifically of the feet. We present the case of a patient, 12 years old girl with primary erythromelalgia who came to our physiotherapy department with features of repeated redness, burning pain, increased warmness of the skin on anterior aspect of right foot. Computer Assisted Capillary Microscopy demonstrated reduced capillary density and capillary perfusion. Another observatory test was done by elevating patient's right leg noting the reversal in skin color from red to pale.Her detailed evaluation was carried out and physiotherapy treatment was started.