透皮促进剂对胰岛素离子导入大鼠体内血糖水平的影响

研究了几种常用透皮促进剂如月桂氮　酮(azone,AZ),油酸(oleicacid,OA),泊洛沙姆(poloxamer188,POL188)和丙二醇(propyleneglycol,PG)等对胰岛素离子导入大鼠体内血糖水平的影响。结果显示:离子导入3h后,100%AZ和5%AZ/PG处理组,处理后对处理前的大鼠血糖变化百分率(D%)分别为38.58%和25.28%,而对照组的为45.48%。100%OA,10%OA/PG,10%POL188%和100%PG处理组的D%分别为66.28%,60.47%,76.75%和57.93%。表明月桂氮　酮与离子导入有协同作用,丙二醇能够增强这种作用,3者并用有特别显著的促渗作用。而油酸、泊洛沙姆、丙二醇不增强离子导入的作用。离子导入和某些透皮促进剂并用,为多肽类药物的体内给药提供了新的思路和可能性。     

褪黑激素皮肤渗透性的研究(英)

本文考察了渗透促进剂Azone（AZ）、油酸（OA）、丙二醇（PG）等和离子导入法（Ag／AgCl或Pt电极,电流密度0.19mA／cm2,频率2000Hz,占／空比1：1）对褪黑激素（MT）皮肤渗透性的影响。MT能透过小鼠全皮,其稳态流量和渗透系数分别为1622×10-3μg／cm2．s和0.8888×10-6cm／s：100％AZ、5％AZ／PG和10％OA／PG处理皮肤后,MT的稳态流量分别是未处理组的7.61、7.03和2.98倍;MT作为非离子性药物,离子导入对其也有促渗作用,离子导入处理组的稳态流量是未处理组的2.19倍。结果表明渗透促进剂（AZ、OA）、离子导入法均能增加MT的经皮渗透。     

不同促渗剂对盐酸氨酮戊酸原位凝胶体外透皮吸收的影响

目的：研究不同透皮促渗剂对盐酸氨酮戊酸原位凝胶体外透皮吸收的影响,为筛选最佳透皮促渗剂提供实验依据。方法：采用Franz扩散池法,以离体大鼠皮肤为模型,选择3种常用透皮促渗剂月桂氮芯卓酮（azone,AZ）、丙二醇（propylene glycol,PG）、二甲亚砜（dimethyl sulfoxide,DMSO）,分别考察单一促渗剂及二元促渗剂对盐酸氨酮戊酸原位凝胶体外透皮吸收的影响。结果：含促渗剂盐酸氨酮戊酸原位凝胶体外透皮吸收显著高于未添加促渗剂盐酸氨酮戊酸原位凝胶及市售制剂;采用单一促渗剂时,1% PG促渗效果最好;采用二元促渗剂时,3% AZ+1% PG促渗效果最好;3% AZ+1% PG促渗效果优于1% PG,含促渗剂3% AZ+1% PG的盐酸氨酮戊酸原位凝胶透皮性优于市售制剂艾拉。结论：添加促渗剂的方法能够显著改善盐酸氨酮戊酸的体外透皮吸收性,3% AZ+1% PG构成的二元促渗剂用于盐酸氨酮戊酸原位凝胶促渗效果最佳;本研究为设计优良的盐酸氨酮戊酸经皮给药系统药物奠定了重要基础。     

增渗剂和离子导入对尼莫地平体外经皮渗透性的影响

研究了增渗剂和离子导入技术对尼莫地平（ＮＭ）体外经皮渗透性的作用,渗透促进剂如３％和５％月桂氮卓酮及１０％油酸的２０％丙二醇溶液能增加药物的渗透性（Ｐ＜００５）,其增渗比分别为４６６、４３９及１２６４．离子导入技术能够显著增加药物的渗透性（Ｐ＜００１）,渗透比为８０３．同时表明１０％油酸和３％的月桂氮卓酮丙二醇溶液与离子导入并用,渗透比为１５、８５、８９２．     

不同渗透促进剂对复方盐酸多塞平乳膏体外经皮的促渗作用研究

目的研究不同浓度油酸和氮酮及其复合物对复方盐酸多塞平乳膏透皮吸收的影响,提高乳膏中两种主要有效成分盐酸多塞平和醋酸曲安奈德的渗透效果.方法选用1%氮酮(aonze,AZ)、2%AZ、1%油酸(oleic acid,OA)、2%OA、1%OA-AZ 5种渗透吸收促进剂,采用离体小鼠皮为皮肤模型,在Franz扩散池上进行促渗实验.结果 5种渗透吸收促进剂对复方盐酸多塞平乳膏中盐酸多塞平促渗能力为2%AZ＞1%OA-AZ＞2%OA＞1%AZ＞1%OA;对醋酸曲安奈德促渗能力为2%AZ＞1%OA-AZ＞1%AZ＞2%OA＞1%OA.结论在所选的5种渗透促进剂中,选用2%AZ渗透促进剂对复方盐酸多塞平乳膏体外经皮促渗作用最显著,油酸、氮酮联合应用有协同作用,比单用氮酮或油酸促渗能力强.     

透皮促渗方法联合应用的研究进展

透皮给药系统具有传统给药方式不可比拟的优势。但由于药物的低渗透量，使其应用受到一定限制。各种物理的、化学的促渗方法，包括透皮吸收促进剂、超声导入法、离子导入法、电穿孔法等可改善皮肤透过性，增加药物的透皮速率。而且几种方法联合应用的促渗效果更加显著。本文总结了近年来各种促渗方法联合应用的研究进展。     

3种吸收促进剂对酮基布洛芬经不同皮肤层渗透的影响

目的：对不同性质的吸收促进剂影响药物经不同皮肤层渗透的差异进行评价。方法：选择氮酮（AZ），肉豆蔻酸异丙酯（IPM）和单月桂酸甘油酯（GML）为透皮促进剂，以酮基布洛芬为模型药物，采用Franz吸收池法，考察药物单儿或与促进剂合用时，完整皮肤和剥离角质层皮肤的透皮能力。结果：剥离角质层皮肤可明显增加酮基布洛芬的透皮层。3种吸收促进剂对药物经完整皮肤的促透能力为IPM＞GML＞AZ，对药物经剥离角质层皮肤的促透能力为GML＞IPM＞AZ。结论：皮肤的条件能明显影响酮基布洛芬的经皮渗透；吸收促进剂对酮基布洛芬经不同皮肤层的促透能力有差异。     

电致孔-离子导入技术对胰岛素经皮给药促渗作用的研究

目的:以胰岛素为模型药物,大鼠的离体皮肤为皮肤模型,采用电致孔-离子导入联合物理促渗新技术,进行体外经皮导入生物大分子药物的研究。方法:以胰岛素为实验药物,采用经皮被动扩散方法,分别考察人体、家兔、小鼠、大鼠离体皮肤的透皮速率,从而进行皮肤模型的筛选;在预实验的基础上,选择pH值分别为4.0、6.0、7.4的三种渗透介质,采用离子导入法,考察渗透介质对胰岛素经皮渗透量的影响,从而确定渗透介质最适pH;应用电致孔-离子导入并用、电致孔、离子导入技术,在生理pH7.4、阴极转运条件下,对胰岛素的经皮渗透量进行考察,并与胰岛素的被动扩散经皮给药进行比较。结果:胰岛素对人体、家兔、小鼠、大鼠皮肤的透皮速率分别为0.78±0.03×10-1u/cm2·h、2.25±0.18×10-1u/cm2·h、2.02±0.19×10-1u/cm2·h、1.12±0.14×10-1u/cm2·h;在pH值分别为4.0、6.0、7.4的三种渗透介质中,胰岛素的经皮渗透速率分别为18.28±1.06×10-1u/cm2·h、9.42±0.29×10-1u/cm2·h、8.66±0.40×10-1u/cm2·h;采用电致孔-离子导入并用、离子导入、电致孔技术对胰岛素经皮促渗时,胰岛素的渗透速率分别达到19.63±6.37×10-1u/cm2·h、8.66±0.40×10-1u/cm2·h、1.83±0.07×10-1u/cm2·h。结论:电致孔-离子导入并用技术能够显著地促进生物大分子体外经皮给药的渗透速率。     

透皮促进剂对酮基布洛芬体外经皮渗透的影响

酮基布洛芬(KP)体外经皮渗透性实验研究表明,KP经皮渗透是一个零级速率过程。利用离体鼠皮为渗透屏障考察KP在月桂氮艹卓酮(AZ)、油酸(OA)、1-甲基-2-吡咯烷酮(2P)、N,N-二甲基甲酰胺(DMF)、月桂醇(LA)、丙二醇(PG)6种透皮促进剂作用下的透皮效果,发现这些透皮促进剂对KP透皮速率的影响有明显差别。其中油酸、月桂氮艹卓酮、1-甲基-2-吡咯烷酮和丙二醇可促进KP吸收透皮,促进强度依次为OA>AZ>2P>PG,并且两种透皮促进剂OA与AZ或2P合用有较好的协同作用,而DMF、月桂醇和高浓度丙二醇则阻滞KP经皮渗透。     

电场方向对电穿孔技术促进咖啡因经皮渗透的影响

目的研究电场方向对电穿孔技术促进咖啡因经皮渗透的影响。方法应用水平双室扩散池,Ag-Ag/AgCl电极和人尸体皮肤,进行咖啡因的经皮渗透实验,考察电场方向对电穿孔(指数衰减型脉冲,脉冲幅度为350 V,脉冲率为4 pulses·min-1,脉冲数为25,电容为22μF )促渗作用的影响,并与离子导入(0.25 mA·cm-2,持续4小时)进行比较。结果 1)电穿孔与离子导入均可显著增加咖啡因的经皮渗透速率和累积渗透量。2)阳极离子导入(电场方向为从供应室到接受室)的促渗作用显著大于阴极离子导入(电场方向为从接受室到供应室)的促渗作用。3)阳极电穿孔的促渗作用与阴极电穿孔的促渗作用无显著差异。4)阳极离子导入的促渗作用显著大于阳极电穿孔及阴极电穿孔的促渗作用。结论电场方向对离子导入的促渗作用有显著影响,而对电穿孔的促渗作用没有影响。     

Transdermal iontophoresis

Iontophoresis is a technique used to enhance the transdermal delivery of compounds through the skin via the application of a small electric current. By the process of electromigration and electro-osmosis, iontophoresis increases the permeation of charged and neutral compounds, and offers the option for programmed drug delivery. Interest in this field of research has led to the successful delivery of both low (lidocaine) and high molecular drugs, such as peptides (e.g., luteinising hormone releasing hormone, nafarelin and insulin). Combinations of iontophoresis with chemical enhancers, electroporation and sonophoresis have been tested in order to further increase transdermal drug permeation and decrease possible side effects. In addition, rapid progress in the fields of microelectronics, nanotechnology and miniaturisation of devices is leading the way to more sophisticated iontophoretic devices, allowing improved designs with better control of drug delivery. Recent successful designing of the fentanyl E-TRANS iontophoretic system have provided encouraging results. This review will discuss basic concepts, principles and applications of this delivery technique.     

Transdermal iontophoresis of sodium nonivamide acetate. V. Combined effect of physical enhancement methods

The effect of iontophoresis combined with treatment of other physical enhancement methods such as electroporation, low frequency ultrasound, and erbium:YAG (yttrium-aluminum-garnet) laser on the transdermal delivery of sodium nonivamide acetate (SNA) was examined in this present study. Iontophoresis increased the transdermal flux of SNA in vitro as compared to the passive diffusion without any enhancement. Furthermore, iontophoresis was always the most potent enhancement method for SNA permeation among the physical enhancement methods tested. Pulsing of high voltages (electroporation) followed by iontophoresis did not result in increased transport over iontophoresis alone. However, electroporation shortened the onset of transdermal iontophoretic delivery of SNA. Pretreatment of low frequency ultrasound (sonophoresis) alone on skin did not increase the skin permeation of SNA. The combination of iontophoresis and sonophoresis increased transdermal SNA transport more than each method by itself. The enhancement of drug transport across shunt routes and reduction of the threshold voltage in the presence of an electric field may contribute to this synergistic effect. Use of an erbium:YAG laser was a good method for enhancing transdermal absorption of SNA because it allows precise control of stratum corneum (SC) removal, and this ablation of SC could be reversible to the original normal status. The combination of laser treatment and iontophoresis also synergized the skin permeation of SNA, possibly due to a gradual drop in the electric resistance of the skin. The results in this present study point out that the choice of certain conditions with suitable physical enhancement methods can induce a synergistic effect on transdermal delivery of SNA during iontophoresis.     

Passive and iontophoretic delivery of three diclofenac salts across various skin types

The in vitro permeation of three diclofenac salts--diclofenac sodium (DFS), diclofenac potassium (DFP) and diclofenac diethylammonium (DFD)-across skin by both passive and iontophoretic transport were investigated. Various skin types were used as the barriers to elucidate the mechanism controlling transdermal delivery of diclofenac salts. The importance of the intercellular (paracellular) route for both DFS and DFP in passive permeation was elucidated. The transfollicular route constitutes an important permeation pathway for DFS but not for DFP. The route and mechanism for transdermal iontophoresis of DFD across the skin was somewhat different to that of the other salts. Hair follicles may be a more important pathway for DFD than for DFS and DFP under iontophoresis, while the intercellular lipid pathway showed the opposite result. Combination of iontophoresis and a penetration enhancer, cardamom oil, did not show a synergistic effect on diclofenac salt permeation. The results of this investigation suggest that the transdermal mechanism and the route of diclofenac salt uptake via passive and iontophoretic transport can be affected by their counterions.     

Iontophoresis - an approach for controlled drug delivery: a review

The recent approval of lidocaine hydrochloride and epinephrine combined iontophoretic patch (Lidosite Vysteris Inc.) for localized pain treatment by FDA has invigorated the gaining interest in iontophoretic drug delivery systems for the transdermal delivery of drugs. This technique of facilitated movement of ions across a membrane under the influence of an externally applied electric potential difference, is one of the most promising physical skin penetration enhancing method. The rationale behind using this technique is the capability of this method to increase the systemic delivery of high molecular weight compounds with controlled input kinetics and minimum inter-subject variability, which is otherwise achieved only when parentral route of administration is used. Recently, good permeation of larger peptides like insulin has been achieved through this technique in combination with chemical enhancers. This review briefly describes the factors which affect iontophoretic drug delivery and summarizes the studies conducted recently using this technique in order to achieve higher systemic absorption of the drugs having low passive diffusion otherwise. The effect of permeation enhancers (chemical enhancers) on iontophoretic flux of drugs has also been described. Present review also provides an insight into reverse iontophoresis. Various parameters which affect the transdermal absorption of drugs through iontophoresis like drug concentration, polarity of drugs, pH of donor solution, presence of co-ions, ionic strength, electrode polarity etc. have also been reviewed in detail.     

Transdermal iontophoresis of insulin: III. Influence of electronic parameters

Transdermal iontophoresis is a physical enhancement strategy primarily for charged molecules and offers a number of advantages for the delivery of peptides and proteins. The singular advantage of iontophoresis lies in the precise control of dose by manipulating the current protocol. The objective of the present investigation was to understand the role of electronic parameters on iontophoretic transport of large peptides using insulin as a model peptide. Ex vivo permeation experiments were conducted using excised rat skin and the influence of varying current strengths, duration, on/off ratios and switching iontophoresis on insulin permeation were studied. High performance liquid chromatography (HPLC), polyacrylamide gel electrophoresis (SDS-PAGE) and thin layer chromatography (TLC) were used to assess the electrochemical stability of insulin; while Fourier transform infra-red (FT-IR) spectroscopy and thermogravimetric analysis (TGA) were used to understand the biophysical changes in skin during iontophoresis. The permeation of insulin was found to increase as a function of current strength and duration of current application. Skin barrier integrity and electrochemical stability of insulin was dependent on the charge applied during iontophoresis. FT-IR spectroscopy and TGA studies showed that the skin hydration increased with increase in the charge applied and thus facilitated the transport of insulin. Periodic iontophoresis did not show any significant difference in insulin permeation compared with continuous current application; 1:1 on/off ratio resulted in higher amount of insulin permeation, while flux was highest with mixed duty cycle. Switching iontophoresis was useful in reducing the pH shift and in improving the electrochemical stability of insulin at pH 3.6 and 7.4, respectively. The electroosmotic flow was influenced by the pH of the donor medium, as well as by the electrode polarity during switching and non-switching iontophoresis. Overall, the study demonstrates the issues related to the optimization of electronic parameters for the iontophoretic delivery of a large peptide.     

Transdermal iontophoresis of insulin. VI. Influence of pretreatment with fatty acids on permeation across rat skin

The delivery of large peptides through the skin poses a significant challenge, and various strategies are under active investigation for enhancing the transdermal permeation. For large peptides, it is difficult to achieve significant permeation using iontophoresis alone. Hence a combination of fatty acids with iontophoresis was hypothesized to result in higher enhancement than achieved with either of them alone. Saturated fatty acids and cis unsaturated fatty acids were studied in combination with iontophoresis using excised rat skin. The skin was pretreated for 2 h with an ethanolic (EtOH) solution of 5% w/v or v/v fatty acids, namely lauric acid (LA), oleic acid (OA), linoleic acid (LOA) and linolenic acid (LLA), followed by either passive or iontophoretic permeation (0.5 mA/cm2 for 6 h). Fourier transform infrared spectroscopy (FT-IR) was used to investigate the biophysical changes on treatment with fatty acid/EtOH or neat fatty acid, mainly focusing on the infrared region at 2,920, 1,710 and 1,720 cm(-1). Unsaturated fatty acids showed higher enhancement than LA, and the enhancement increased with the number of double bonds. On the other hand, in the presence of iontophoresis, LA/EtOH showed the highest enhancement. Neat LOA did not show any significant difference (p > 0.05) compared to the LOA/EtOH combination. FT-IR studies revealed that fatty acids act by interacting with the skin lipids. All the fatty acids showed synergistic enhancement when combined with iontophoresis. The flux enhancement was highest with LA, which in the presence of iontophoresis showed 20 times enhancement of insulin flux in comparison to passive flux and 9 times enhancement as compared to iontophoresis alone. Flux enhancement of unsaturated fatty acids was in the following decreasing order LOA > OA > LLA.