J. Jiang

Enhancing effect of electret on transdermal drug delivery

Abstract The present work was undertaken to study the enhancing effect of electret on in vitro transdermal drug delivery. The experiment was conducted using the improved Franz diffusion cells, with the skin of rat mounted between the two half cells and the electret film covered on the model compound in the donor cell. The receiver solution was withdrawn at a predetermined time and the concentration was measured by high performance liquid chromatography (HPLC). The results showed that the penetration flux of methyl salicylate in the electret group was 1.55 times greater than that in the control group. This indicated that the microcurrent and static field that the electret produced could influence the drug permeation through the skin.

Evaluation of penetration enhancement of lidocaine by porous PTFE/PE/PP electret through mouse skin in vitro

The main object of this study was to systemically evaluate the effect of porous PTFE/PE/PP electret on lidocaine transdermal delivery and to compare its enhancing effect with some commonly used chemical permeation enhancers, that is propylene glycol, oleic acid and menthol. The composite electret was prepared by heat melting method at 130/spl square/. The modified Franz diffusion cell was used to carry out the in vitro permeation experiment and a high performance liquid chromatography (HPLC) was employed to analyze the drug concentration. The drug solution containing no chemical permeation enhancer or no electret application was taken as control group. The results indicated that: (1) The feasibility of using porous PTFE/PE/PP electret to enhance the lidocaine transdermal delivery was achieved by applying positively charged electrets with different surface potentials. The enhancing effect was proportional to the surface potential of the electret. (2) The chemical permeation enhancers used were shown to be less effective than the +1000 V electret on lidocaine transdermal permeation. The 24 hours cumulated permeation amount of lidocaine reached to 3.649, 6.029, 8.619, 6.330 and 17.218 mg for control group, 10% oleic acid, 20% propylene glycol, 1% menthol and porous PTFE/PE/PP electret, respectively. In conclusion, positively charged electret can be used as the enhancer to increase the transdermal permeation of lidocaine.

Preparation of porous PTFE/PE/PP composite electret and study of its charge storage stability

In this paper we introduced the preparing process and corona charging method of the porous PTFE/PE/PP composite electret film, and furthermore, studied its charge storage stability by using the method of isothermal surface potential decay measurement, open-circuit thermally stimulated discharge current spectra. It was shown that 1) charge storage stability for negative porous PTFE/PE/PP composite electret corona charged at high temperature was almost the same as that of porous PTFE electret charged at room temperature. 2) The charge storage stability of porous PTFE/PE/PP electret was closely related to the structure of porous PTFE and charging condition. 3) Porous PTFE/PE/PP electret exhibited higher charge storage stability than porous PTFE electret under high humidity.

Enhanced transdermal delivery of cyclosporine a by PP electret and ethyl oleate

Transdermal delivery of high molecular weight compound is a great challenge due to the barrier function of the skins outer stratum corneum (SC) layer. The aim of the present work was to characterize in vitro transdermal delivery of cyclosporine A through rat skin and the drug transdermal enhancing effect of PP electret applied individually and in combination with chemical enhancer. The permeated cumulative amount and steady state flux of the cyclosporine A were determined in following situations: (a) under application of PP electret, (b) after application of ethyl oleate, (c) combination PP electret and ethyl oleate. All the techniques could enhance cyclosporine A transdermal delivery. The combination of PP electret and ethyl oleate proved to be the most effective technique.

Effect of electret on surface charge of red blood cell in scalded rats

The electrophoretic mobility (EPM) and contents of sialic acid (SA) on the red blood cell (RBC) were determined by means of cell electrophoresis and SA micro-chemical calorimetry to explore the mechanism of effect electret on surface charge of RBC in scalded rats. The results indicated that (1) EPM and SA contents of RBC in each period after rat scalded were decreased significantly as compared with those of in control group. (2) In negative electret group, EPM and SA contents were increased markedly with time. (3) Positive electret showed no notable effect on EPM and SA contents of RBC after rats were scalded. Negative electret can improve the microcirculation and hematological rheology index of scalded rats by stabilizing the SA contents of RBC to repair the electret state of RBC in scalded rats.

Optimizing the formulation of cyclosporine A electret patch and the controlled release of drug

The polypropylene (PP) film coated with/without aluminum electrode were charged with the gird voltages of −500 V, −1000 V and −2000 V to prepare the electrets and produce electric field for control of drug release. The model drug of cyclosporine A (CsA) was loaded on a patch and ethyl oleate was used as the chemical enhancer in the manufacturing process. The formulation of the CsA drug patch enhanced by chemical was optimized, and the in vitro release behaviours of drug in the patches were studied to explore the enhancing effect of the external electrostatic field on the CsA release from the patch. Besides, the piezoelectric d33 coefficient was also determined to study the polarization of the drug in the patch under the action of the internal electrostatic field of the electret. The results indicate that the electrostatic field produced by the electret could polarize the drug in patch and enhance the release of CsA from the patch, and the effect depended on the electrode coating condition and charging voltage of the electret.

Thermal analysis for studies of electret states of rat skin

The open thermally stimulated discharge (TSD) and differential thermal analysis (DTA) were employed to study the electret state and its forming mechanism of the rat skin. The appearance of one dipole peak and two space charge peaks in open TSD current spectra indicated that skin is an excellent natual electret. Corresponding to the TSD spectra, three typical phase transition were detected in DTA spectra at about 63°C, 82.7°C and 115.1°C, respectively. The lamellar lipid structure, collegan network structure and protein space structure are the main explanation of the formation of skin electret state. Besides, hydration in skin will strengthen the electret effect of the skin.

Evaluation of pharmacodynamics of porous PTFE/PE/PP electret meloxicam patch

In this paper, the pharmacodynamic effects of porous PTFE/PE/PP electret meloxicam patch on anti-inflammatory and analgesia were evaluated. The results showed that electret meloxican patch took advantage of the pharmacological effects of meloxicam and characteristics of electret that can adjust skin in biological electret state and weaken pain caused by injure and enhance the effect of analgesia and anti-inflammation.

In vivo study of percutaneous absorption of lidocaine using electret in the rat

The present work was undertaken to study the effect of electret on transdermal drug delivery in vivo. The experiment was carried out in depilated abdominal rat skin using lidocaine hydrochloride as a model compound. Rats were divided into control and electret group. The electrets were applied on the drug in a vial and the blood samples were taken from jugular vein at predetermined time intervals. The concentration of lidocaine in plasma was measured by high proficiency liquid chromatograph (HPLC) after extraction. The plasma lidocaine concentration was significantly increased in electret group. The results suggested that electret could promote the permeability of drug by its effect on the structure of epidermis and blood flow change.