乙酰唑胺对表达水孔蛋白1的非洲爪蟾卵母细胞转运水功能的影响

目的观察乙酰唑胺对水孔蛋白1(AQP1)水转运功能的影响。方法将AQP1 cRNA 10 ng注射入非洲爪蟾卵母细胞,观察并记录给予1×10^-7～1×10^-5 mol·L^-1乙酰唑胺后卵母细胞在低渗溶液中的膨胀率,并计算其渗透水通透性(Pf)的变化。结果非洲爪蟾卵母细胞表达AQP1蛋白后,在低渗溶液中迅速膨胀,Pf值显著增加至1.82×10^-2 cm·s^-1,而注射水的阴性对照仅为0.25×10^-2 cm·s^-1。AQP抑制剂HgCl₂使Pf值降至0.64×10^-2 cm·s^-1;1×10^-7～1×10^-5 mol·L^-1乙酰唑胺处理后,Pf值分别降至1.43,1.24和0.93×10^-2 cm·s^-1。结论乙酰唑胺剂量依赖性地降低AQP1介导的渗透水通透性,抑制AQP1转运水的功能。     

依达拉奉凝胶的制备及体外透皮性能研究

目的 考察依达拉奉凝胶体外经皮渗透性,筛选凝胶剂最佳处方。方法 采用Valin-Chien双室渗透扩散池,以大鼠离体皮肤为渗透屏障,以HPLC测定依达拉奉的浓度,考察含药量、月桂氮（艹卓）酮用量、环糊精的型号和含量对依达拉奉凝胶剂经皮渗透性的影响。结果 凝胶剂最佳处方为6%依达拉奉、10%月桂氮（艹卓）酮、10% β-环糊精、2%羧甲基纤维素钠,依达拉奉12 h累积渗透量平均值为(501.95±27.59)μg·cm^-2,渗透速率平均值为(42.25±7.39)μg·cm^-2·h^-1。结论 依达拉奉凝胶剂具有较好的经皮渗透特性,有望成为新的给药制剂。     

利拉萘酯喷雾剂的经皮渗透研究

目的 研究利拉萘酯喷雾剂的经皮渗透性。方法 采用改良Franz扩散池,以小型猪皮肤为渗透屏障,高效液相色谱法测定利拉萘酯含量。结果 利拉萘酯喷雾剂和乳膏剂的稳态透皮速率分别为(0.017±0.006),(0.014±0.003)μg·cm^-2·h^-1;利拉萘酯喷雾剂和乳膏剂的24 h累积渗透量分别为(0.60±0.23),(0.44±0.15)μg·cm^-2;利拉萘酯喷雾剂和乳膏剂在皮肤中的药物残留量分别为(8.2±1.3),(7.7±1.6)μg·g^-1。结论 利拉萘酯喷雾剂的稳态透皮速率、24 h累积渗透量、在皮肤中的药物残留量均稍大于利拉萘酯乳膏剂,但2种剂型之间没有显著性差异。     

在体猪耳静脉灌流经皮吸收模型的建立与应用

目的建立在体猪耳静脉灌流经皮吸收模型，为经皮吸收制剂研究提供新方法。方法建立在体猪耳静脉灌流经皮吸收模型。以葡萄糖利用试验及乳酸脱氢酶活性检测评价模型的生物学活性，以酮洛芬异丙酯和水杨酸甲酯为模型药物考察系统的应用。结果葡萄糖利用及乳酸脱氢酶活性检测表明系统7 h内保持良好生物学活性。酮洛芬异丙酯经皮渗透过程中被完全代谢为酮洛芬，稳态时酮洛芬累积形成量Q与时间t回归的方程为Q=-0.024+0.120t，形成速率为0.120　μg·cm^-2·h^-1。水杨酸甲酯经皮渗透过程中部分被代谢为水杨酸，稳态时水杨酸甲酯累积渗透量Q与时间t回归的方程为Q=-3.809+6.129　t，渗透速率为6.129　μg·cm^-2·h^-1；水杨酸累积形成量Q与时间t回归的方程为Q=-1.785+0.879　t，形成速率为0.879　μg·cm^-2·h^-1。结论该模型操作简便、价格经济，不仅可以考察药物的经皮吸收，而且能够用于研究药物的皮肤代谢。     

基于透皮离子导入技术的戒烟药物金雀花碱的可控递送研究

目的 探索烟碱乙酰胆碱受体部分激动剂金雀花碱(cytisine，CTS)经阳极离子导入透过离体猪皮。方法 采用HPLC-PDA建立并验证CTS的分析方法。研究了电流密度、药物浓度和药物基质对CTS透皮离子导入的影响。采用标志物对乙酰氨基酚解析CTS离子导入过程中电迁移和电渗的贡献。结果 CTS从水溶液中被动透皮不佳，但在离子导入条件下CTS的透皮递送量显著增加，将电流密度从0.15 mA·cm^–2增加到0.5 mA·cm^–2可使离子导入CTS的稳态流量呈线性增加(J=452.8I+31.51，r=0.998 3)。在使用0.5 mA·cm^–2电流密度的条件下，给药池药物浓度的增加(2.5，5.0，10.0 mg·mL^–1)可使累积透皮递送量显著增加。共离子导入对乙酰氨基酚证实了电迁移是CTS的主要递送机制(˃90%)。CTS的传导效率良好(6.63%~8.82%)。递送效率，即递送药物占所给予的制剂中的药物的百分数较高(在0.5 mA·cm^–2时>40%)。CTS从离子导入贮库HEC水凝胶中递送时的累积透皮递送量为(1 551.94±322.19)μg×cm^–2，与从CTS溶液中递送时的累积透皮递送量无统计学差异。结论 体外数据表明，使用较小面积的凝胶贴片通过透皮离子导入可以方便地递送治疗剂量的CTS。     

他克莫司软膏的制备及体外经皮渗透评价

目的 研制与原研制剂经皮渗透性能一致的他克莫司软膏。方法 用LC-MS/MS测定样品中他克莫司的含量；以剪切应力、复合黏度等流变性参数和累积释放量为指标，筛选他克莫司软膏处方；采用改良Franz扩散池，以小型猪皮肤为渗透屏障，研究他克莫司软膏的经皮渗透性能。结果 自制他克莫司软膏的剪切应力(剪切速率：30 s^-1)为145.8 Pa、复合黏度为16.11 Pa·s、释放速率为(1 400±243)ng·cm^-2·h^-1/2、经皮渗透速率为(40.28±3.11)ng·cm^-2·h^-1、皮肤内滞留量为(9.515±1.096)ng·mg^-1；原研制剂的剪切应力(剪切速率：30 s^-1)为141.8 Pa、复合黏度为15.88 Pa·s、释放速率为(1 243±133)ng·cm^-2·h^-1/2、经皮渗透速率为(37.61±9.09)ng·cm^-2·h^-1、皮肤内滞留量为(8.463±1.770)ng·mg^-1。结论 自制他克莫司软膏与原研制剂的流变性和释放速率相似，经皮渗透性无显著性差异。     

碳糊电极阳极伏安法测定秋水仙碱

在0.05mol·L^-1H₂SO₄介质中,用碳糊电极(石墨粉:液体石蜡油=1.5∶1)阳极扫描伏安法测定秋水仙碱,检测限1×10^-7mol·L^-1,检测线性范围4.0×10^-7～1×10^-3mol·L^-1,氧化时出现两个氧化峰,峰电位分别为1.07V和1.33VvsSCE,峰电位随pH值升高而正移。对原料和片剂进行了测定,均获得满意的结果。     

遗传算法在经皮给药微乳载体处方优化中的应用

以萘普生为模型药物，用遗传算法优化经皮给药微乳载体的处方。用伪三元相图法确定由Tween 80、IPM、乙醇和水组成的微乳区域。用3因素3水平的中心设计法制备载药量为1.12%的萘普生模型微乳，并进行离体兔皮的体外渗透实验。以稳态渗透速率的二次回归模型为目标函数，用遗传算法对中心设计结果进行优化，筛选出具有最大透皮速率的萘普生微乳载体处方。所得优化处方的组成为：21.41% Tween 80、15.17%乙醇、4.14% IPM和59.28%水，预计的稳态渗透速率为183.57 μg·cm^-2·h^-1。回代试验表明，以优化处方制备的萘普生微乳，其稳态渗透速率的平均值为189.43 μg·cm^-2·h^-1，高于预测值。结果表明，用遗传算法筛选微乳经皮给药载体处方，方法可行，结果合理、可靠。     

脉冲电流对胰岛素经皮渗透的促进作用

实验结果表明,脉冲电流能有效地提高胰岛素的透皮扩散速率,并随着释放池中胰岛素浓度的递增,透皮扩散速率呈线性增加。同时,胰岛素在pH值偏离等电点的酸性溶液(pH3.6)中透皮速率最高,为324.2±33.4μU/(cm²·h),而在pH值高于等电点的溶液(pH7.4)中其透皮速率降至143.7±27.3μU/(cm²·h),在pH值接近等电点(pH5.3)时,胰岛素的透皮速率最低,为78.4±21.9μU/(cm²·h)。     

水溶性帕利哌酮前体药物的合成及其体外透皮研究

目的 合成帕利哌酮（PPD）的水溶性前体药物,使其能通过离子导入技术快速透过皮肤。方法 合成PPD的水溶性前体药物,即PPD的β-丙氨酸酯（PPD-β-Ala）,并对前药进行结构确证;利用高效液相色谱（HPLC）建立PPD及PPD-β-Ala的定量分析方法,并进行方法学验证;测定PPD及PPD-β-Ala的饱和溶解度,并对PPD-β-Ala的脂水分配系数（P_o/w）和pKa进行考察;进行PPD-β-Ala体外透皮实验,包括被动透皮吸收和离子导入透皮研究;在体外离子导入研究中,考察给药池介质[纯水、HEPES溶液（pH 5.5）或HEPES溶液（pH 6.5）]、给药池药物浓度（10、20、30 mmol·L^-1）和电流密度（0.1、0.3、0.5 mA·cm^-2）对PPD-β-Ala透皮递送量的影响。结果 前体药物PPD-β-Ala结构通过核磁共振氢谱得以确证。建立的HPLC法可对PPD及PPD-β-Ala同时检测,方法专属性、精密度和检测限均满足实验要求。PPD-β-Ala在纯水中的饱和溶解度为33.46 mmol·L^-1,远高于PPD的水溶解度;PPD-β-Ala的lg P_o/w小于PPD;PPD-β-Ala可充分质子化,带1个正电荷,PPD不具备易解离或易质子化的基团。PPD-β-Ala不易透皮吸收,但在离子导入条件下可在接收池中检出大量PPD-β-Ala,如在施加电流0.5 mA·cm^-2条件下,当给药池中PPD-β-Ala的浓度为30 mmol·L^-1时,7 h后的累积透皮递送量可达250 nmol·cm^-2。所选给药池介质的变化未对PPD-β-Ala的累积透皮递送量产生明显改变,但给药池药物浓度和电流强度的增加均能提高PPD-β-Ala的累积透皮递送量。在体外离子导入研究各组中均发现大量的PPD和PPD-β-Ala蓄积于皮肤,以0.5 mA·cm^-2电流强度、给药池药物浓度为20 mmol·L^-1（HEPES溶液为介质,pH 5.5）的给药条件为例,蓄积于皮肤中的PPD和PPD-β-Ala的量分别可达（144.21±41.73）、（890.61±106.40） nmol·cm^-2。结论 水溶性离子化的PPD前药PPD-β-Ala可在离子导入过程中通过电迁移作用快速透皮,理论上可利用尺寸适中的离子导入透皮贴片满足PPD的最小日给药剂量。     

Effect of electroporation and iontophoresis on skin permeation of Defibrase--a purified thrombin-like enzyme from the venom of Agkistrodon halys ussuriensis Emelianov

The purpose of this study was to investigate electroporation and iontophoresis as a means for in vitro delivery of Defibrase--a thrombin-like enzyme (TLE) from Agkistrodon halys ussuriensis Emelianov snake venom--through human epidermis membrane (HEM). Electroporation was carried out using an exponential decay pulse generator (BioR-ad Genepulser, USA) for a period of 0.5 h, followed by a period of 5.5 h passive diffusion or iontophoresis. The results indicated that the combined use of electroporation and anodal iontophoresis in pH 6.4 permeation medium could effectively enhance the skin permeation of Defibrase, whose apparent permeability coefficient was 1.6 +/- 0.8 x 10(-4) cm.h-1. The delivery of Defibrase by the combined use of electroporation and anodal iontophoresis was more effective than by electroporation alone (P < 0.01) or by the combined use of electroporation and cathodal iontophoresis (P < 0.01). Moreover, when the pH of the permeation medium was raised from 6.4 to 7.4 the permeation of Defibrase caused by a combined use of electroporation and anodal iontophoresis showed a tendency to increase. These results implied that electroosmotic flow effect might be important for the iontophoretic (following electroporation) skin permeation of Defibrase.     

The effects of pH and ionic strength on topical delivery of a negatively charged porphyrin (TPPS4)

Meso-tetra-[4-sulfonatophenyl]-porphyrin (TPPS(4)) is a charged porphyrin derivate used in photodynamic therapy (PDT) by parenteral administration. This study means to investigate potential enhancement for its topical delivery by determining the TPPS(4) dependence on the environmental characteristics and applying iontophoresis. In order to accomplish this task, cathodal and anodal iontophoresis as well as passive delivery of the drug were studied in vitro and in vivo in function of its concentration, pH and ionic strength. A reduction in drug concentration as well as the NaCl elimination from donor formulation at pH 2.0 increased TPPS(4) passive permeation through the skin in vitro. Iontophoresis improved TPPS(4) delivery across the skin when applied in solutions containing NaCl at pH 2.0, regardless electrode polarity. However, at pH 7.4, the amount of TPPS(4) permeated by iontophoresis was not different from that one permeated after passive experiments from a solution containing NaCl. Despite the fact that iontophoresis did not improve TPPS(4) transdermal delivery at this specific condition, in vivo experiments showed that 10 min of iontophoresis quickly and homogeneously delivered TPPS(4) to deeper skin layers when compared to passive administration, which is an important condition for topical treatment of skin tumors with PDT.     

The Influence of Iontophoresis on Acyclovir Transport and Accumulation in Rabbit Ear Skin

Purpose The aim of this work was to explore the effect of iontophoresis on acyclovir (ACV) accumulation and permeation. In particular, the objectives were to check the efficacy of the transport mechanisms, electromigration and electroosmosis, on drug accumulation.Methods Permeation experiments were performed in vitro, using rabbit ear skin as barrier, from donor solutions at pH 3.0, 5.8, and 7.4. At the end of the experiments, drug accumulation in epidermis and dermis was measured. Anodal and cathodal iontophoresis were applied at pH 3.0, whereas only anodal iontophoresis was used at pH 5.8 (current densities 0.06–0.50 mA/cm²) and 7.4.Results Cathodal iontophoresis was more efficient than anodal iontophoresis on ACV permeation across the skin at pH 3.0. At pH 5.8, ACV flux and accumulation increased with current density during anodal iontophoresis. At pH 7.4, anodal iontophoresis produced a remarkable increase of flux and a modest increase of accumulation. Overall, anodal flux increased as the pH of the donor solution was increased as a result of the increase of the skin net negative charge.Conclusions From the results obtained in the present work, it can be concluded that iontophoresis application increases ACV flux and, to a limited extent, accumulation in the skin.     

The effects of iontophoresis and electroporation on transdermal delivery of buprenorphine from solutions and hydrogels

The in-vitro permeation of buprenorphine across skin was investigated to assess the effects of iontophoresis and electroporation on drug permeation from solutions as well as from hydrogels. Iontophoresis (0.3 mA cm(-2)) increased the buprenorphine permeation from solution by a factor of 14.27 as compared with passive diffusion; the application of electroporation increased the buprenorphine permeation from solutions by a factor of 8.45. The permeation experiments using cellulose membrane and stratum corneum (SC)-stripped skin as permeation barriers suggested that the enhancement with iontophoresis was primarily due to strong electrophoretic drift of buprenorphine molecules, whereas the enhancement seen with electroporation was mainly attributed to the creation of transient aqueous pores in the SC layer. Application of high-voltage pulses followed by iontophoresis resulted in a shorter permeation onset time from both solutions and hydrogels as compared with iontophoresis or electroporation alone. The charge repulsion between buprenorphine and chitosan vehicles as well as the competition effects of counter-ions for carboxymethylcellulose (CMC)-based polymers may account for the different permeation rates under electrical field. This study demonstrates the feasibility of using hydrogels for delivery of buprenorphine under the application of iontophoresis or electroporation, separately or together.     

Facilitated skin penetration of lidocaine: combination of a short-term iontophoresis and microemulsion formulation

The objective of this study was to demonstrate the potential of the application of a short-term iontophoresis on the topical delivery of lidocaine hydrochloride from a microemulsion-based system. Five- and 10-min durations of anodal iontophoresis applied onto porcine skin were examined in combination with a microemulsion containing 2.5% lidocaine hydrochloride. A similar combination (10-min iontophoresis with microemulsion in the anodal electrode) was also examined in vivo in a rat model. It was shown in vitro that by combining microemulsion application with a 10-min iontophoresis of 1.13 mA/cm2 electric current density, a significantly increased flux was obtained compared with a combination of aqueous drug solution with the same iontophoresis protocol. In vivo studies revealed that 57.71 +/- 18.65 and 18.43 +/- 9.17 microg cm(-2) were reached in the epidermis and dermis, respectively, at t = 30 min of microemulsion application, when iontophoresis was applied for 10 min. In contrast, the application of aqueous solution-iontophoresis resulted in a relatively lower drug accumulation (21.44 +/- 10.42 and 5.30 +/- 2.25 microg cm(-2) in the epidermis and dermis, respectively, at t = 30) with more rapid clearance of the drug from the skin. Ten-minute application of a low-current electric field on a new topical microemulsion appears to make significant changes in skin permeability. The potential advantages of this procedure include significantly increased flux, accumulation of a large skin drug depot, short lag times, reduced irritation (compared to long-term iontophoresis), simplicity and ease of compliance.     

Improvement of epidermal barrier properties in cultured skin substitutes after grafting onto athymic mice

Barrier function in cultured skin substitutes (CSS) prepared from human cell sources was measured by noninvasive (surface hydration, transepidermal water loss) and invasive methods (water permeation, niacinamide flux) before and after grafting onto athymic mice. In vitro measurements were made on days 7 and 14. Although three of the four measures of barrier function improved markedly from day 7 to 14, the values obtained were still far from those obtained with native human skin controls. Additional CSS were grafted onto athymic mice on day 14, and skin was harvested 2 and 6 weeks after grafting. Grafting brought about a substantial decrease in all measurements by 2 weeks and almost complete normalization of barrier function after 6 weeks. The most sensitive measure of this recovery was niacinamide permeability, which decreased from (280 +/- 40) x 10(-4) cm/h in vitro to (17 +/- 30) x 10(-4) cm/h 2 weeks after grafting and (5 +/- 2) x 10(-4) cm/h 6 weeks after grafting, versus control values of (2 +/- 2) x 10(-4) cm/h in human cadaver skin and (0.6 +/- 0.4) x 10(-4) cm/h in human epidermal membrane prepared from freshly excised breast skin. These results demonstrate the reformation of epidermal barrier function after transplantation and provide insights for the development of a functional epidermal barrier in CSS in vitro.     

Transdermal iontophoretic delivery of methylphenidate HCl in vitro

Methylphenidate is prescribed orally for Attention Deficit Disorder in children and adults, and for narcolepsy patients. Methylphenidate has a short plasma half-life (1-2 h) and thus needs to be frequently administered for effective therapy. Such therapy has limitations in terms of patient compliance, particularly in young children. For such reasons, the development of a transdermal dosage form of methylphenidate may be useful. This study was undertaken to evaluate the passive and electrically assisted transport (iontophoresis) of methylphenidate from aqueous methylphenidate hydrochloride solutions across excised human skin. A maximum flux of 12.0 micrograms/(cm2 h) of protonated methylphenidate was estimated from the passive transport data at pH 3.5. Iontophoresis significantly enhanced protonated methylphenidate transport as compared with passive delivery. From the present experiments, the efficiency of iontophoretic delivery of methylphenidate was approximately 700 micrograms/(mA h). Based on in vitro skin flux data, the daily dose of 15-40 mg methylphenidate can be achieved using a current density of 0.5 mA/cm2 and a minimum transport area of 2-5 cm2 for 24-h application, or an area of 4-10 cm2 for 12-h (daytime) application. From methylphenidate skin flux values, methylphenidate mobility of 2.2 x 10(-4) cm2/(V s) was estimated, which compares reasonably with its free solution mobility of 6.6 x 10(-4) cm2/(V s).     

Passive and iontophoretic transdermal penetration of methotrexate

The in vitro iontophoretic transdermal delivery of methotrexate (MTX) across pig skin was investigated. Cathodal iontophoresis considerably increased MTX skin permeation and accumulation as compared to the passive controls. The effect of NaCl and MTX concentrations in the vehicle were also studied. As expected, MTX iontophoretic transport decreased with NaCl content. On the other hand, MTX concentration did not modify its electrotransport in the range of concentrations considered (4.4-6.6 mM). The influence of the current density (0.25-0.5 mA/cm2) was also investigated. The iontophoretic transport of MTX tends to increase with current density although this effect was not always statistically significant. Finally, the possibility of using anodal iontophoresis from an acid (pH 4.0-5.0) donor solution to deliver MTX was explored. This was limited due to the low solubility of MTX in acid pH. On the whole, this work that iontophoresis may be used to improve the topical application of MTX for the treatment of psoriasis.     

Combined effects of iontophoretic and chemical enhancement on drug delivery. II. Transport across human and murine skin

This paper reports measurements of the release characteristics of the model drug salbutamol from a liquid crystalline vehicle across both human and hairless murine skin in vitro. The use of oleic acid and iontophoresis as penetration enhancement techniques, used separately and simultaneously, was also investigated. Over a period of 12h, salbutamol base did not diffuse from the vehicle across excised human skin while, in contrast, over a period of 2h, the drug passively transported across hairless murine skin. The diffusion co-efficient for the drug in this tissue was estimated to be 4.54+/-0.60x10(-9)cm(2)s(-1) with a permeability co-efficient of 7.03+/-0.83x10(-7)cms(-1). A current of density of 0.39mAcm(-2) facilitated a significant transport of salbutamol from the liquid crystalline vehicle across excised human skin but with a small (<0.1) transport number. The quantity of salbutamol transported across excised hairless murine skin under the same conditions was significantly greater with a transport number of 0.68. The alteration of the permeability of the tissue was less than that of the human skin and a full recovery of the pre-iontophoretic permeability of murine skin was consistently observed. The incorporation of either oleic or lauric acid into the monoglyceride component of the vehicle at a concentration of 0.1M had a marked effect on the transport of salbutamol across both human and murine skin. The initial passive permeation of the drug across the skin was not affected but the rate of drug delivery during iontophoresis was typically observed to increase by a factor greater than two. The post-iontophoretic transport of salbutamol across either tissue was also substantially enhanced in the presence of the fatty acid. The analogous use of stearic acid did not significantly influence the iontophoretic or the post-iontophoretic transport of salbutamol across excised human skin. The investigation also revealed a synergistic combination of the fatty acid and anodal iontophoresis to enhance the in vitro transport of other drug substances, including nicotine and diltiazem hydrochloride across murine skin. Oleic acid increased both the iontophoretic and post-iontophoretic transport of nicotine, so that the enhancement of drug delivery was greater than that caused by the current alone. The investigation also indicated that the barrier properties of the skin recover following the constant current iontophoresis in the presence of oleic or lauric acids.     

Quantification and localization of fentanyl and trh delivered by iontophoresis in the skin

Autoradiography and the technique of stripping/slicing were used in order to investigate the pathways and to quantify drug penetration into skin after iontophoresis of two model compounds: fentanyl, a lipophilic molecule and TRH, a hydrophilic molecule. Iontophoresis was performed for 1, 4 and 6 h at a mean current density of 0.33 mA/cm² and was compared to passive diffusion. The quantification studies showed that iontophoresis increases the drug concentration in the part of the skin limiting molecule permeation: viable skin for fentanyl and stratum corneum for TRH. Even though, besides accumulation, autoradiography allows one to localize the route of passage, observations tend to confirm that transepidermal penetration can take place and that an important route of penetration is the transappendageal pathway.