In Vitro Evaluation of a Hydroxypropyl Cellulose Gel System for Transdermal Delivery of Timolol

Abstract

In this work, the development of a gel reservoir for a timolol (TM) transdermal iontophoretic delivery system is investigated. TM gel is prepared using hydroxypropyl cellulose (HPC) and the permeability of TM from the gel through an artificial membrane (Polyflux) and pig stratum corneum (SC) is studied. For a constant TM donor concentration, the TM transport across the Polyflux membrane alone decreases when the concentration of the gel increases due to increase of the gel viscosity. For constant gel concentration, however, the TM permeation across the membrane increases when the TM donor concentration increases. In addition, no effect of the electrical current (iontophoresis, current density 0.5 mA cm-2) on the TM permeation is found. For the combination of the Polyflux membrane with pig SC, the TM transport is much lower than for the membrane alone and the SC fully controls the TM delivery. In this case, the application of electrical current enhances the TM delivery 13-15 times in comparison to passive (no current) transport. According to our estimation, the daily TM dose (10-60 mg) can be delivered by an iontophoretic patch with Polyflux membrane area of 6-36 cm2 containing 20% (w/w) HPC gel and 15 mg cm-3 of TM.

Medical applications of membranes: Drug delivery, artificial organs and tissue engineering

“…In almost all patches, an artificial membrane is used in direct contact with the skin which should be made of biocompatible material to avoid skin irritation and have low drug adsorption. In recent studies in our group, several membranes have been evaluated in transdermal patches containing TM [44,[54][55][56] and salmon calcitonin (sCT) [57]. Tables 1 and 2 present some results of drug adsorption to commercial membranes [44,57].…”

Cellulose-Derivatives-Based Hydrogels as Vehicles for Dermal and Transdermal Drug Delivery

“…The therapeutic effects of above-mentioned electrically assisted techniques, used alone as well in combination or further, in conjunction with chemical enhancers, for transdermal drug delivery were intensively investigated [110,[142][143][144][145][146][147]. Furthermore, hydrogels proved to be suitable formulations for assisted transdermal delivery by ionophoresis, sonophoresis, and electroporation due to their advantageous characteristics such as ease of loading into the device, suitability with the electrode design, good flexibility and fitting with the skin contour, strength, transparency, stability, and high electrical conductivity, which is attributed to their high water content [116,148,149].…”

Emerging Concepts in Analysis and Applications of Hydrogels

“…The therapeutic effects of above-mentioned electrically assisted techniques, used alone as well in combination or further, in conjunction with chemical enhancers, for transdermal drug delivery were intensively investigated [110,[142][143][144][145][146][147]. Furthermore, hydrogels proved to be suitable formulations for assisted transdermal delivery by ionophoresis, sonophoresis, and electroporation due to their advantageous characteristics such as ease of loading into the device, suitability with the electrode design, good flexibility and fitting with the skin contour, strength, transparency, stability, and high electrical conductivity, which is attributed to their high water content [116,148,149].…”