皮肤中蛇床子素分布的测定

目的 研究抗银屑病蛇床子素贴剂经皮渗透后蛇床子素在皮肤中不同深层的分布。方法 将抗银屑病蛇床子素贴剂经皮渗透一定时间后，分别采用了胶带剥离技术、皮肤萃取法测定了角质层、去角质层皮肤中蛇床子素含量。结果 蛇床子素在皮肤内的滞留量与贴剂使用的时间呈依赖性，用药时间越长，皮肤药物量达到平台期的深度越深，即意味着药物透过皮肤的量越大。结论 蛇床子素在角质层的滞留量远大于去角质皮肤的量，蛇床子素在角质层中的浓度较高，可以形成贮库效应。在贴剂取下后，角质层中的药物可能缓慢地扩散到皮肤的更深层而产生缓释的效果。     

花椒毒素在人体皮肤及角质层中的渗透动力学探讨

目的探讨花椒毒素在人体完整皮肤及其角质层中的渗透动力学特性。方法采用人体离体皮肤及从完整皮肤中分离出的角质层，在Franz-cell扩散池中进行不同浓度的花椒毒素乙醇溶液(0.1, 0.5, 2.5和5.0 mg·mL^-1)的渗透实验，均采用1.4%的人血清溶液作为接收液，用HPLC法测定各接收液的药物量和皮肤中的贮存药物量。结果花椒毒素乙醇溶液单位面积透过完整人皮肤速率随着浓度增加而增加，2.5 mg·mL^-1以上的浓度对其速率几乎无影响。在角质层中也存在同样的现象，但其单位面积透皮速率最大值提前了约6 h。而且随着给药浓度的增加，24 h后完整皮肤和角质层的药物贮存量也相应增加，但达到一定浓度后存在饱和现象。且花椒毒素乙醇溶液在完整皮肤中的透皮时滞(0.82 h)明显大于在角质层中的透皮时滞(0.47 h)。结论该结果对开发花椒毒素外用制剂时浓度的选择提供了依据，并对其外用药物后照射长波段紫外光(UVA)的时间提供了参考。     

三维荧光光谱法测定蛇床子素在离体皮肤中不同深度的分布

目的 运用三维荧光光谱分析新技术能提供丰富的光谱信息的特点，研究了蛇床子素在不同皮层的分布趋势。方法 将经蛇床子素贴剂渗透后的皮扶进行水平恒冷切片，将切片平铺在石英玻璃上用三维荧光光谱仪测定其荧光强度。结果 以发射波长为X轴，激发波长为Y轴，荧光强度为Z轴，构成了三荧光光谱图，从角质层开始皮肤切片的荧光强度依次减弱。结论 利用三维荧光光谱和指纹图谱可有效地检定出皮肤中分布的蛇床子素，并可以初步判断出蛇床子素在皮肤中的量化分布趋势。     

曲安奈德经皮渗透特性研究

目的 评价曲安奈德经皮渗透的特性.方法 采用Franz扩散池法,考察药物经完整皮肤和去角质层皮肤的体外透皮能力,并采用了胶带剥离、皮肤萃取法分别获取了皮肤角质层、去角质层皮肤样本,用HPLC法测定了样本中的药物含量,考察曲安奈德在皮肤不同层的分布情况.结果 曲安奈德的24h透过量去角质层皮肤约为完整皮肤的1.6倍;8h...     

派瑞松乳膏中3种药物透皮特性的研究

目的:评价派瑞松乳膏中曲安奈德(TACA)、苯甲酸(BEN)、硝酸益康唑(ECN)3种药物的透皮特性.方法:采用Franz扩散池法,考察药物经完整皮肤和去角质层皮肤的体外透皮能力,并采用了胶带剥离、皮肤萃取法分别获取了皮肤角质层、去角质层皮肤样本,用HPLC法测定了样本中的药物含量.结果:经过24 h透皮吸收,TACA和BEN的去角质层皮肤渗透量分别为完整皮肤的1.5和1.3倍,ECN的渗透量基本为零.8h透皮实验,TACA高、中、低3个浓度角质层中药物含量基本相同,真皮层则存在浓度依赖现象;ECN在皮肤各层和接受室均检测不到;BEN在角质层和真皮层中的分布与TACA相似,但透过量比TACA大.结论:角质层是皮肤渗透的重要屏障,派瑞松乳膏应用于皮肤溃疡、受损或者婴幼儿皮肤仍需谨慎.     

曲安奈德经皮渗透特性研究

目的评价曲安奈德经皮渗透的特性。方法采用Franz扩散池法,考察药物经完整皮肤和去角质层皮肤的体外透皮能力,并采用了胶带剥离、皮肤萃取法分别获取了皮肤角质层、去角质层皮肤样本,用HPLC法测定了样本中的药物含量,考察曲安奈德在皮肤不同层的分布情况。结果曲安奈德的24 h透过量去角质层皮肤约为完整皮肤的1.6倍;8 h透皮实验,高、中、低3个浓度角质层中药物含量基本相同,真皮层则存在浓度依赖现象。结论角质层是曲安奈德的透皮吸收重要屏障,但角质层对药物的储留有饱和现象,临床上应用时需特别关注。     

基于药物-皮肤的相互作用探究盐酸特比萘芬体外透皮特性

目的 考察盐酸特比萘芬的体外透皮特性，探究盐酸特比萘芬与皮肤的相互作用，基于药物-皮肤相互作用阐明盐酸特比萘芬透皮特性的机制。方法 比较盐酸特比萘芬经皮渗透及其皮内滞留以及在皮肤各层的分布；利用衰减全反射红外光谱、差示扫描量热、拉曼光谱研究药物与皮肤的相互作用，并对药物与角质层角蛋白及脂质的相互作用进行计算机模拟和计算。结果 盐酸特比萘芬经皮渗透后高滞留低渗透，滞留的药物多分布于角质层。盐酸特比萘芬与角质层中脂质和角蛋白均有相互作用，该作用使药物自身难于透过皮肤，并导致较大的透过变异性。结论 盐酸特比萘芬与皮肤脂质和角蛋白的相互作用是其表现出典型的皮肤低渗透、高滞留特性的机制之一。本研究为盐酸特比萘芬体外透皮高滞留、低渗透特性提供理论依据。     

用电致孔法促进环孢素A的皮肤滞留

目的研究致孔电压、致孔时间及脉冲模式对环孢素A在大鼠皮肤各层中滞留的影响。方法将质量分数为0.5%的环孢素A的乙醇(体积分数为40%)混悬液应用于离体大鼠皮肤,同时在大鼠皮肤施加电致孔。实验结束后,用胶带剥离法分离角质层,HPLC法测定角质层和大鼠去角质层皮肤及接受液中的药物含量。结果大鼠表皮和真皮中环孢素A的含量随致孔电压的升高略有增加,随致孔时间的增加而增加,使用3次/min的脉冲模式大鼠去角质层中的药物滞留量最多,并且使用电致孔这一物理促渗法未显著增加接受液中环孢素A的含量。结论电致孔法能够提高环孢素A皮肤局部用药效果,从而减少药物体循环带来的不良反应。     

角质层与活性皮肤层对硝酸异山梨酯透皮吸收的影响

目的:评价皮肤角质层和真皮层对药物经皮吸收的影响。方法:以硝酸异山梨酯(ISDN)为模型药物,采用Franz吸收池法,考察药物单独或与吸收促进剂肉豆蔻酸异丙酯(IPM)合用时,经完整皮肤和角质层剥离皮肤的透皮能力。结果:IS-DN经剥离角质层皮肤的表观透皮系数的Kp是经完整皮肤的1.68倍,IPM能分布在活性皮肤层,并可明显增加ISDN在角质层或真皮层的分布量及经皮累积透皮吸收百分率。结论:本实验为研究皮肤病态条件下(如皮肤受伤或溃疡等),药物透皮吸收规律,提供了一种新的方法。     

角质层及其类脂对5-氟脲嘧啶经皮渗透的作用

采用离体皮肤扩散等技术研究了5-Fu在人皮肤各层次中的渗透性质和1,8-CN对药物渗透及皮肤热转变的影响。实验表明5-Fu在皮肤各层次中有相近分配系数,但扩散性质不同。角质层、全皮层、脱脂角质层和去角质层全皮扩散系数依次为1.32×10^-7,1.01×10^-7,1.37×10^-6和54.09×10^-6cm²/h。用1,8-CN处理上述皮肤样品12h后,5-Fu在各组织的分配均减少,角质层和全皮的通透性显著增加(P<0.05),对去脂角质层和去角质层全皮的通透性无明显影响。结合DSC分析证明,角质层是5-Fu经皮渗透的重要屏障,类脂对5-Fu的扩散和1,8-CN的增效具重要意义。     

Comparison of poultice-type and tape-type patches containing ketoprofen on human skin irritation

Although the patch test for visual skin observation is widely used clinically, it does not allow the mechanisms of side effects to be assessed. In this study, we examined poultice-type KP801 and tape-type KP-T patches containing ketoprofen. The parameters to measure side effects on skin were peeling intensity, amount of stripped stratum corneum, skin moisture and redness of skin color under various mechanical conditions. Since the amount of stripped stratum corneum with the tape-type KP-T patch was higher than with the poultice-type KP801 patch, the bio-adhesive strength of the latter was concluded to be lower. A clear relationship exists between the amount of stripped stratum corneum and skin moisture after tape-type patch removal, but this was not found with the poultice-type patch because of its hydration effects. Peeling intensity, one parameter to predict pain at the time of patch removal, was higher with the KP-T. As for mechanical conditions, when the patch is removed, it is important to remove it as slowly as possible and horizontally, and to avoid any rise in skin temperature. Finally, when a patch is applied to a region with little skin moisture, the amount of stripped stratum corneum may increase accordingly.     

Selective removal of stratum corneum by microdermabrasion to increase skin permeability

This study sought to determine if microdermabrasion can selectively remove stratum corneum to increase skin permeability. Although, microdermabrasion has been used for cosmetic treatment of skin for decades, no study has assessed the detailed effects of microdermabrasion conditions on the degree of skin tissue removal. Therefore, we histologically characterized the skin of rhesus macaques and human volunteers after microdermabrasion at different conditions. Using mobile tip microdermabrasion, an increase in the number of treatment passes led to greater tissue removal ranging from minimal effects to extensive damage to deeper layers of the skin. Of note, these data showed for the first time that at moderate microdermabrasion conditions selective yet full-thickness removal of stratum corneum could be achieved with little damage to deeper skin tissues. In the stationary mode of microdermabrasion, selective stratum corneum removal was not observed, but micro-blisters could be seen. Similar tissue removal trends were observed in human volunteers. As proof of concept for drug delivery applications, a model fluorescent drug (fluorescein) was delivered through microdermabraded skin and antibodies were generated against vaccinia virus after its topical application in monkeys. In conclusion, microdermabrasion can selectively remove full-thickness stratum corneum with little damage to deeper tissues and thereby increase skin permeability.     

蛇床子素凝胶药物经皮吸收的体外研究

目的体外测定含有渗透促进剂的蛇床子素凝胶经人体皮肤的吸收.方法以离体人皮肤为渗透模型,应用Franz扩散池进行实验.样品以高效液相法测定蛇床子素的含量.结果与对照组相比,渗透促进剂Azone、薄荷醇、土荆芥油可以使得蛇床子素的稳态流量分别提高3.12、2.00、1.25倍.结论三种渗透促进剂的作用机理为破坏了皮肤角质层的屏障作用,降低了药物的扩散阻力,因而提高了蛇床子素的扩散系数.     

Fluorescence recovery after photo-bleaching as a method to determine local diffusion coefficient in the stratum corneum

Fluorescence recovery after photo-bleaching experiments were performed in human stratum corneum in vitro. Fluorescence multiphoton tomography was used, which allowed the dimensions of the photobleached volume to be at the micron scale and located fully within the lipid phase of the stratum corneum. Analysis of the fluorescence recovery data with simplified mathematical models yielded the diffusion coefficient of small molecular weight organic fluorescent dye Rhodamine B in the stratum corneum lipid phase of about (3-6) × 10(-9)cm(2) s(-1). It was concluded that the presented method can be used for detailed analysis of localised diffusion coefficients in the stratum corneum phases for various fluorescent probes.     

Human stratum corneum penetration by copper: in vivo study after occlusive and semi-occlusive application of the metal as powder.

Aim of the study was to shed light on the long-standing controversy whether wearing copper bangles benefits patients suffering from inflammatory conditions such as arthritis. Sequential tape stripping was implemented on healthy volunteers to examine the diffusion of copper through human stratum corneum in vivo following application of the metal as powder on the volar forearm for periods of up to 72 h. Exposure sites were stripped 20 times and the strips analyzed for metal content by inductively coupled plasma-mass spectroscopy with a detection limit for copper of 0.5 ppb. Untreated skin was stripped in the same fashion, to determine baseline copper levels for comparison with exposure values resulting from exposure in respective volunteers. Under occlusion with exclusion of air, up to 72 h copper values decreased from the superficial to the deeper layers of the stratum corneum with gradients increasing commensurately with occlusion time, characteristic of passive diffusion processes. From the tenth strip on, however, levels reverted to background values. Under semi-occlusion allowing access of air by covering the skin with "breathable" tape, initial copper values lay significantly above baseline values and concentration gradients increased proportionally with occlusion time. At 72 h, from the tenth to the twentieth strip reaching the glistening epidermal layer, copper values continued at constant levels, significantly above baseline values. The results indicate that, in contact with skin, copper will oxidize and may penetrate the stratum corneum after forming an ion pair with skin exudates. The rate of reaction seems to depend on contact time and availability of oxygen. A marked inter-individual difference was observed in baseline values and amounts copper absorbed.     

长春西汀透皮贴剂的研制及体外释药机理的探讨

目的:制备长春西汀透皮贴剂,研究其体外释药机理.方法:在单层贴剂优化处方的基础上制备了单层、双层和三层贴剂,比较不同类型贴剂经不同皮肤的体外渗透速率,对三层贴剂进行了质量考察并研究了其释药机理.结果:三层贴剂和双层贴剂的经皮渗透量大于单层贴剂.去除角质层的皮肤对药物经皮渗透的屏障作用明显小于完整皮肤. 结论:长春西汀贴剂质量可控,刺激性小,药物经皮吸收的主要屏障为角质层,在经皮渗透中有较微弱的储库效应,其渗透行为主要是零级释药模式.     

Correlation between stratum corneum/water-partition coefficient and amounts of flufenamic acid penetrated into the stratum corneum

The stratum corneum of various donors differs in particular in the composition of the lipoidal phase. Considering the drug amounts penetrating into the stratum corneum a simple methodology to correlate these differences in the stratum corneum composition with the drug amounts detectable within the stratum corneum is desirable. Penetration experiments investigating several incubation times were carried out with three different skin flaps using the Saarbruecken penetration model and the lipophilic model drug flufenamic acid. The drug amounts within the stratum corneum were obtained with the tape-stripping technique, while the drug amounts present in the deeper skin layers were achieved by cryosectioning. The stratum corneum/water-partition coefficient was determined with the same three skin flaps to characterize the lipoidal stratum corneum phase in general, and the differences were attributed to the different amounts of ceramides and sterols. In addition, for the lipophilic drug flufenamic acid, a direct linear correlation was found between the stratum corneum/water-partition coefficients and the drug amounts penetrated into the stratum corneum for all investigated time intervals (correlation coefficients of r(30 min) = 0.998, r(60 min) = 0.998 and r(180 min) = 0.987). In contrast to the stratum corneum/water-partition coefficients, the determination of a corresponding relationship for the stratum corneum and the deeper skin layers failed due to the reason that steady-state conditions could not be achieved for the deeper skin layers during the investigated time intervals. In summary, the stratum corneum/water-partition coefficients offer the possibility to predict drug amounts within the stratum corneum of different donor skin flaps without a time consuming determination of the lipid composition of the stratum corneum.     

Penetration,distribution and kinetics of 2,3,7,8-tetrachlorodibenzo-p-dioxin in human skin in vitro

The in vitro penetration of³H-labeled 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) into human cadaver skin was studied at concentrations of 65 and 6.5 ng TCDD per cm² of skin surface. Vehicles used were acetone to simulate exposure to TCDD as a dry material, and mineral oil to simulate exposure to TCDD in an oily medium. Penetration was performed for 30, 100, 300, and 1000 min in improved Franz cells. Skin was used either intact, or with stripped horny layer. Skin was sectioned along its natural layers and radioactivity determined in epidermis and dermis. TCDD did not readily penetrate into human skin in vitro. The vehicle of exposure to TCDD played an important role in dermal penetration. The rapidly evaporating acetone allowed TCDD to penetrate deeply into the loose surface lamellae of the horny layer, but then appeared to be poorly available for further penetration. Mineral oil as the vehicle, on the other hand, represented a lipophilic compartment which competed with lipophilic constituents of the stratum corneum for TCDD and hence slowed its penetration even more. The stratum corneum acted as a protective barrier, as its removal increased the amount of TCDD absorbed into layers of the skin. Hourly rates of absorption of TCDD per unit area of skin were calculated in two ways: a worst case scenario where TCDD absorbed into any layer of skin including the stratum corneum was used for regression analysis; and a physiological approach where only that amount of TCDD was considered absorbed which had penetrated beyond the epidermis into the region of dermal vascularization. Under worst case scenario conditions the stratum corneum appeared to mediate dermal absorption of TCDD, since calculated rates of absorption decreased when skin stripped of its stratum corneum was exposed to TCDD. This was, however, not the case with the physiological approach. There was a consistent relationship between concentration of TCDD applied and concentration of TCDD found in skin. Also, a clear-cut correlation was found between the amount of TCDD that penetrated and the time of exposure. The rate of penetration into intact skin of different concentrations of TCDD from acetone ranged from 100 to 800 pg TCDD per hour and cm² of skin (worst case scenario), or 6 to 170 pg per hour and cm² with the physiological approach. With mineral oil as the vehicle the rate of penetration into intact skin was lower, ranging from 20 to 220 pg and 1.4 to 18 pg, respectively, per hour and cm² of skin. Our results on the distribution of TCDD in human skin also suggest that as yet unknown constituents of epidermis and upper dermis have a somewhat higher affinity towards TCDD than those of the lower dermis.Presented in part at the 28th Annual Meeting of the Society of Toxicology, Atlanta, GA, 1989