Potential of iontophoresis as a drug delivery method for midazolam in pediatrics

Influencing factors and drug application of iontophoresis in transdermal drug delivery: an overview of recent progress

Transdermal drug delivery is limited by the stratum corneum of skin, which blocks most molecules, and thus, only few molecules with specific physicochemical properties (molecular weight < 500 Da, adequate lipophilicity, and low melting point) are able to penetrate the skin. Recently, various technologies have been developed to overcome the strong barrier properties of stratum corneum. Iontophoresis technology, which uses a small current to improve drug permeation through skin, is one of the effective ways to circumvent the stratum corneum. This approach not only provides a more efficient, noninvasive, and patient-friendly method of drug delivery but also widens the scope of drugs for transdermal delivery. In this review, the mechanisms underlying iontophoresis and affecting factors are outlined. The focus will be on the latest advancements in iontophoretic transdermal drug delivery and application of iontophoresis with other enhancing technologies. The challenges of this technology for drug administration have also been highlighted, and some iontophoretic systems approved for clinical use are described.

Electrically controlled transdermal delivery of naproxen and indomethacin from porous cis-1,4-polyisoprene matrix

This study is focused on the inquiry of using a porous polymeric structure to absorb and release transdermally two drugs through a skin from deproteinized natural rubber latex (DPNR). The porous DPNR films were fabricated from the internal formation of surfactant micelles and their subsequent leaching out to generate porous structures. The pore size of DPNR films increased with increasing surfactant amount. The model drugs were naproxen and indomethacin; their releases and release-permeations were investigated under the effects of surfactant amount, electrical potential, and drug size. Without electric field, the drug release mechanism was mainly driven by concentration gradient. The higher amount of drug released was obtained from the matrix with a larger pore size. Under electric field, the higher amounts of drug release were obtained in the shorter drug release durations, via the electrorepulsive force between the negatively charged drugs and the cathode electrode. The molecular drug size was a factor for the drug absorption, release rate and amount. For the drug release-permeation experiment through the pig skin, there were two release-permeation periods as governed by the combination of concentration gradient and swelling in the first period, and the matrix erosion in the second period. The fabricated porous DPNR films have been shown here to be potential to be used as a transdermal patch with electrically controllable drug release rate, amount and duration along with the facile drug-matrix loading and absorption.

Transdermal iontophoresis delivery system for terazosin hydrochloride: an in vitro and in vivo study

This study aimed to construct a transdermal iontophoresis delivery system for terazosin hydrochloride (IDDS-TEH), which included a positive and negative electrode hydrogel prescription. Intact guinea pig skin was used as a model for the skin barrier function, and the current intensity, terazosin hydrochloride (TEH) concentration, pH, competitive salt, and transdermal enhancer properties were studied. The blood drug concentration was determined in Sprague–Dawley (SD) rats using HPLC, and the antihypertensive effects of IDDS-TEH were evaluated in spontaneously hypertensive rats (SHRs). The results showed that the steady-state penetration rate of TEH increased (from 80.36 µg·cm⁻²·h⁻¹ to 304.93 µg·cm⁻²·h⁻¹), followed by an increase in the current intensity (from 0.10 mA·cm⁻² to 0.49 mA·cm⁻²). The pH values also had a significant influence on percutaneous penetration. The blood concentration of IDDS-TEH was significantly higher (p < .05) than with passive diffusion, which could not be detected. The main pharmacokinetic parameters of the high current group (0.17 mA·cm⁻²) and the low current group (0.09 mA·cm⁻²) were AUC_0–t: 5873.0 ng·mL⁻¹·h and 2493.7 ng·mL⁻¹·h, respectively. Meanwhile, the pharmacodynamic results showed that IDDS-TEH significantly decreased the blood pressure of SHRs compared with the TEH hydrogel without loading current. Therefore, TEH could be successfully delivered by the transdermal iontophoresis system in vitro and in vivo, and further clinical studies should be explored to develop a therapeutically useful protocol.

One-Pot Synthesis of Triazolobenzodiazepines Through Decarboxylative [3 + 2] Cycloaddition of Nonstabilized Azomethine Ylides and Cu-Free Click Reactions

A one-pot synthesis of triazolobenzodiazepine-containing polycyclic compounds is introduced. The reaction process involves a decarboxylative three-component [3 + 2] cycloaddition of nonstabilized azomethine ylides, N-propargylation, and intramolecular click reactions.