渗透促进剂对荜茇提取物中胡椒碱体外经皮吸收的影响

目的研究荜茇提取物中的主要成分胡椒碱的透皮吸收特性,确定最佳促进剂及质量浓度。方法采用卧式双室扩散池,以离体大鼠皮肤作为渗透屏障,用HPLC法测定样品中胡椒碱的质量浓度。以稳态流量(Js)、增渗比(ER)及滞后时间(tlag)为指标考察渗透促进剂对荜茇提取物中胡椒碱体外经皮吸收的影响。结果当用质量分数为10%的N-甲基-2-吡咯烷酮时,胡椒碱的稳态渗透速率最高。结论N-甲基-2-吡咯烷酮为荜茇提取物中胡椒碱经皮给药有效的渗透促进剂。     

氧化苦参碱凝胶体外经皮渗透及大鼠药动学研究

目的 研究氧化苦参碱凝胶的体外经皮渗透影响因素,并对其在大鼠体内的药动学进行研究。方法 采用Valia-Chien 双室扩散池,以大鼠离体皮肤为渗透屏障,HPLC测定氧化苦参碱浓度,以药物累积渗透量为指标,对药物及渗透促进剂的浓度进行筛选。结果 氧化苦参碱经皮凝胶的最优处方12 h累积渗透量为(18.094±1.253)mg·cm^-2,大鼠静注与经皮给药的血浆药动学研究表明,经皮给药的AUC_(0-t)是注射给药的1.9倍(P<0.01)。结论 氧化苦参碱凝胶的经皮吸收能力良好,能长时间持续释放药物,有望成为新的给药剂型。     

促进剂对非洛地平经皮渗透的影响

目的寻找非洛地平经皮渗透促进剂.方法用分光光度法测定非洛地平通过兔皮肤的渗透速率,研究不同的促进剂对非洛地平经皮渗透的影响.结果松节油-氮酮(11)或松节油-油酸(11)的促渗作用比较明显.结论混合促进剂促渗效果比较好.     

新型经皮渗透促进剂的研究进展

介绍国内外近年来报道的新型经皮渗透促进剂的研究与开发进展,重点介绍若干具代表性的新合成的化合物以及新发现的天然产物,包括内酰胺类、糖苷类、氨基酸衍生物、聚合物、挥发油和酶类等,为合成和发现更加安全、高效的促渗剂提供线索.     

普萘洛尔体外经皮渗透及氮酮的促渗作用

本文利用离体兔皮为渗透屏障研究了胶粘剂中分散型普萘洛尔贴膜剂的体外经皮渗透性，考察了透皮吸收促进剂氮酮的增渗效果和该贴膜剂的体外释放行为．结果表明：贴膜剂中普萘洛尔可经皮渗透（渗透速率常数２．２６μｇ／ｃｍ２·ｈ）；氮酮具有促进普萘洛尔经皮渗透作用（渗透速率常数３．０９μｇ／ｃｍ２·ｈ）．普萘洛尔经皮渗透过程遵循零级动力学方程；且体外释药行为可用ｃｈａｎｄｒａｓｅｋａｒａｎ溶出扩散控制转运机制加以解释；该贴膜为皮控型经皮治疗系统．     

芒果苷脂质体的理化性质和体外经皮渗透性能的研究

目的考察制备的芒果苷脂质体的理化性质和经皮渗透性能。方法采用薄膜分散法制备芒果苷脂质体,超速离心法测定包封率,并对粒径、电位进行表征;以大鼠皮肤为渗透屏障,采用Franz扩散池比较芒果苷脂质体和水溶液的体外经皮累积渗透量。结果芒果苷脂质体的粒径为(97.7±1.2)nm、电位为(10.7±0.2)mV,包封率为44.1%。芒果苷脂质体组与水溶液组24 h累积渗透量分别为(171.9±13.43)、(102.5±3.97)μg/cm2。结论脂质体给药系统可有效促进芒果苷的经皮渗透,为芒果苷经皮给药新制剂的研究提供了参考。     

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.     

微针与新型经皮给药载体结合的研究进展

经皮给药系统具有给药方便、血药浓度稳定、无首过效应等优点,但皮肤的屏障作用使得药物难以透过皮肤。近年来,出现了很多新型经皮给药的药物载体,如脂质体、醇质体、囊泡等,这些能通过化学方法促进药物的经皮渗透。而微针能穿透皮肤角质层形成微孔通道,通过物理方法促进药物的渗透,将微针与新型经皮给药载体结合能显著提高药物的经皮吸收的速率。本文对微针与新型经皮给药载体结合的最新研究进行了综述,并展望了微针辅助新型药物载体经皮给药的发展前景。     

口腔黏膜促透剂研究进展

通过查阅资料并选取有代表性的文献进行综述,发现口腔黏膜吸收促进剂是一种能可逆地改变口腔黏膜角质层屏障作用以促进药物的透黏膜吸收,而不对口腔黏膜形成严重刺激和损害的化学物质。常用的促透剂有表面活性剂类、胆盐类、醇类、脂肪酸、萜烯类、环糊精、螯合剂、壳聚糖、Azone等类型,其能增加药物的口腔黏膜透过率,这对于口腔黏膜给药的应用具有重要指导意义。     

透皮促进剂对白花前胡甲素体外经皮渗透的影响

目的:考察透皮促进剂对白花前胡甲素(dl-praeruptorin A,Pd-Ia)体外经皮渗透的影响。方法:采用改进的Franz扩散池,以大鼠离体皮肤为渗透屏障,用高效液相色谱法对Pd-Ia进行含量测定,考察月桂氮酮(Azone)及1%Azone与不同浓度丙二醇(PG)混合物对Pd-Ia透皮吸收的影响。结果:使用Azone对Pd-Ia有促透作用,1%Azone效果较好,平均渗透速率达到4.064μg.cm-2.h-1;1%Azone与15%PG合用促透效果最好,平均渗透速率达到4.889μg.cm-2.h-1,且与单用1%Azone有显著性差异(P<0.05)。结论:1%Azone与15%PG合用时,含0.5%Pd-Ia溶液体外渗透具有最大促透效果,体现出协同作用。     

Overcoming the stratum corneum: the modulation of skin penetration. A review

It is preferred that topically administered drugs act either dermally or transdermally. For that reason they have to penetrate into the deeper skin layers or permeate the skin. The outermost layer of the human skin, the stratum corneum, is responsible for its barrier function. Most topically administered drugs do not have the ability to penetrate the stratum corneum. In these cases modulations of the skin penetration profiles of these drugs and skin barrier manipulations are necessary. A skin penetration enhancement can be achieved either chemically, physically or by use of appropriate formulations. Numerous chemical compounds have been evaluated for penetration-enhancing activity, and different modes of action have been identified for skin penetration enhancement. In addition to chemical methods, skin penetration of drugs can be improved by physical options such as iontophoresis and phonophoresis, as well as by combinations of both chemical and physical methods or by combinations of several physical methods. There are cases where skin penetration of the drug used in the formulation is not the aim of the topical administration. Penetration reducers can be used to prevent chemicals entering the systemic circulation. This article concentrates on the progress made mainly over the last decade by use of chemical penetration enhancers. The different action modes of these substances are explained, including the basic principles of the physical skin penetration enhancement techniques and examples for their application.     

Liposome–skin interactions and their effects on the skin permeation of drugs

The aim of the study was to evaluate the interaction of phospholipid liposomes with skin and stratum corneum lipid liposomes (SCLLs). The influence of phospholipid liposomes on the skin permeability of model drugs was also studied. The transdermal flux of the drugs applied in various phospholipid containing formulations through human epidermis was studied in diffusion chambers. Liposomes in water solutions did not enhance the skin permeability of the drugs, but when ethanol (32% w/v) was present in the donor with EPC (egg yolk lecithin), permeabilities of some model drugs were substantially increased. Confocal microscopy studies revealed that EPC do not penetrate into the skin from water solutions, while from ethanol solutions, EPC penetrates deeply into the stratum corneum. Also, resonance energy transfer between different liposome compositions and the release of calcein from SCLLs showed that interactions between phospholipid liposomes and SCLLs increased with increasing ethanol concentration in the liposome solutions.     

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.     

Transfersomes for transdermal drug delivery

Transfersomes^® (Idea AG) are a form of elastic or deformable vesicle, which were first introduced in the early 1990s. Elasticity is generated by incorporation of an edge activator in the lipid bilayer structure. The original composition of these vesicles was soya phosphatidyl choline incorporating sodium cholate and a small concentration of ethanol. Transfersomes are applied in a non-occluded method to the skin and have been shown to permeate through the stratum corneum lipid lamellar regions as a result of the hydration or osmotic force in the skin. They have been used as drug carriers for a range of small molecules, peptides, proteins and vaccines, both in vitro and in vivo. It has been claimed by Idea AG that intact Transfersomes penetrate through the stratum corneum and the underlying viable skin into the blood circulation. However, this has not been substantiated by other research groups who have extensively probed the mechanism of penetration and interaction of elastic vesicles in the skin. Structural changes in the stratum corneum have been identified, and intact elastic vesicles visualised within the stratum corneum lipid lamellar regions, but no intact vesicles have been ascertained in the viable tissues. Using the principle of incorporating an edge-activator agent into a bilayer structure, a number of other elastic vesicle compositions have been evaluated. This review describes the research into the development and evaluation of Transfersomes and elastic vesicles as topical and transdermal delivery systems.     

Percutaneous and Systemic Disposition of Hexamethylene Lauramide and Its Penetration Enhancement Effect on Hydrocortisone in a Rat Sandwich Skin-Flap Model

The percutaneous absorption and distribution profile of hexamethylene lauramide (hexahydro-1-lauroyl-lH-azepine) were examined using a rat skin-flap model. After a topical dose to the skin flap, the drug concentrations in the vasculature at the site of drug application and in the systemic blood were monitored simultaneously. Hexamethylene lauramide penetrated the skin and reached a steady state in stratum corneum, viable epidermis, dermis, and cutaneous blood in 3 hr. Its concentration in the skin was much higher than that in the blood. Its apparent concentration in the epidermis was 19 times that in the dermis and about 3000 times that in the cutaneous blood. The percutaneous absorption of ¹⁴C-hexamethylene lauramide resulted in ascending systemic blood concentrations throughout the experimental period, whereas the cutaneous blood levels remained steady. The topically absorbed hexamethylene lauramide was quantitatively recovered in urine (85%) and feces (13%). The half-lives of urinary and fecal excretion of ¹⁴C-hexamethylene lauramide were 17 and 30 hr, respectively. Hexamethylene lauramide, when topically coadministered in an experimental formulation, enhanced the skin penetration of hydrocortisone with increased drug contents in the stratum corneum (2-fold) and with increased hydrocortisone concentrations in the cutaneous blood (3.4-fold) and the systemic blood (3.5-fold). The results indicated that the high concentration and retention of hexamethylene lauramide in stratum corneum and viable epidermis may contribute to its penetration enhancement effect in the skin. A steady state in percutaneous tissues was observed before the drug reached distribution equilibrium systemically. The systemic blood concentration of a topically applied agent therefore may not reflect its percutaneous kinetic processes before a systemic distribution equilibrium is reached. Temporal profiles of a topical penetration enhancer in the skin and in the body are important information for the development of dematologic preparations for the treatment of skin disorders.     

Examination of the mechanism of oleic acid-induced percutaneous penetration enhancement: an ultrastructural study

The epidermal permeability barrier appears to be regulated primarily by the lamellar arrangement of lipid bilayers between coneocytes of the stratum corneum and presents a significant barrier to the transdermal delivery of drugs. The aim of the present study was to investigate the effects of oleic acid on the ultrastructure of stratum corneum lipids in rat skin. Wistar rats were treated topically with 10% oleic acid/propylene glycol for 2 h, the structure of stratum corneum was examined by electron microscopy using osmium tetroxide or ruthenium tetroxide postfixation, and the epidermal barrier function was evaluated in a lanthanum tracer study. Ultrastructural examination revealed that there was a marked alteration in the stratum corneum and the tracer penetrated into the intercellular spaces of the stratum corneum after application of oleic acid. These results suggest that ruthenium tetroxide postfixation is a powerful tool for the study of the stratum corneum lipid structure. Oleic acid might increase the epidermal permeability through a mechanism involving the perturbation of stratum corneum lipid bilayers and lacunae formation to enhance transdermal drug delivery.     

Skin Structure and Metabolism: Relevance to the Design of Cutaneous Therapeutics

The outer layer of the epidermis or stratum corneum is the major barrier to percutaneous absorption. It has been shown that there are numerous enzyme systems beneath the stratum corneum in the viable epidermis capable of metabolizing drugs. A number of prodrug and soft drug topical therapeutic agents have been designed. After these agents penetrate the stratum corneum, they are metabolized by the cutaneous esterase systems to the desired metabolites.     

In vitro skin penetration of acetyl hexapeptide-8 from a cosmetic formulation

There is a concern that peptides in cosmetic creams marketed as anti-aging/anti-wrinkle may penetrate into the deep layers of the skin and potentially stimulate biological activity. Claims for one cosmetic peptide, acetyl hexapeptide-8 (Ac-EEMQRR-amide), suggest interference with neuromuscular signaling as its anti-wrinkle mechanism of action. Therefore, the skin penetration of commercially available Ac-EEMQRR-amide from a cosmetic formulation (oil-in-water (O/W) emulsion) was determined in hairless guinea pig (HGP) and human cadaver skin assembled into in vitro diffusion cells. An O/W emulsion containing 10% Ac-EEMQRR-amide was applied to skin at a dose of 2?mg/cm². After a 24-h exposure, the skin surface was washed to remove unabsorbed peptide. Skin disks were tape stripped to determine the amount of peptide in the stratum corneum. Removal of the stratum corneum layers was verified by confocal microscopy. The epidermis was heat separated from the dermis and each skin fraction was homogenized. Skin penetration of Ac-EEMQRR-amide was measured in skin layers by hydrophilic interaction liquid chromatography with tandem mass spectrometry using electrospray ionization (ESI) in the positive mode. Stable isotopically labeled hexapeptides were used as internal standards for the quantitation of native hexapeptides to correct for matrix effects associated with ESI. The results (percent of applied dose) showed that the majority of the Ac-EEMQRR-amide was washed from the surface of both HGP and human skin. Ac-EEMQRR-amide that penetrated skin remained mostly in the stratum corneum of HGP (0.54%) and human (0.22%) with the peptide levels decreasing as each layer was removed by tape stripping. Total Ac-EEMQRR-amide found in the epidermis of HGP and human skin was similar at 0.01%. No peptide was detected in the dermis or buffer collected underneath the skin for both human and HGP. There was no hexapeptide metabolite (H₂N-EEMQRR-amide) detected in any layers of HGP skin, human skin or buffer collected underneath the skin. This skin penetration data will be useful for evaluating the safety of cosmetic products containing small peptide cosmetic ingredients.     

Strategies for overcoming the stratum corneum

Transdermal drug delivery has many advantages over the oral administration of drugs. This is the reason why many researchers have extensively investigated the transdermal absorption of drugs. However, a much smaller number of drugs are marketed using this route of delivery, compared to oral dosage forms, because drug absorption across the skin is very low due to the stratum corneum (the main barrier for drug absorption across the skin). Overcoming the penetration barrier would significantly improve the development of an efficient transdermal drug delivery system. Several techniques have been developed, or are under development, to bypass the stratum corneum. Approaches that have been made to overcome the stratum corneum fit into five different categories: (i) device and formulation; (ii) modification of stratum corneum by chemical enhancers; (iii) ablation; (iv) bypassing the stratum corneum via appendages; and (v) electrically assisted methods such as iontophoresis and electroporation. Furthermore, possible combinatorial uses of several approaches have been studied. Although the safety issues of these synergistic approaches still require clarification, several combinations could be promising. Finally, there is a necessity to regulate the intradermal disposition of drugs to develop a more efficient transdermal drug delivery system after overcoming the skin barrier.     

In Vitro Percutaneous Absorption of Arildone,a Highly Lipophilic Drug,and the Apparent No-Effect of the Penetration Enhancer Azone in Excised Human Skin

Purpose. Arildone, a novel lipophilic antiviral drug when evaluated in Clinical Trials showed limited skin absorption and antiviral efficacy. These studies were conducted to explain the apparent poor absorption characteristics and attempt to promote skin absorption by using Azone, a penetration enhancer. Methods. Standard in vitro skin permeation methods using excised human skin were employed to characterise the absorption of Arildone. ¹⁴C-Arildone was used to estimate the distribution in skin layers by scintigraphic and autoradiographic procedures. Results. The aqueous solubility and distribution constant values for Arildone were 2 µg ml^–1 and 5 × 10⁵ (isopropyl myristate/water), respectively. Absorption through full thickness skin or stratum corneum-viable epidermal membranes (diffusional resistant dermis removed), from a propylene glycol vehicle, was slow and the addition of Azone had no effect on the permeation rate. Distribution studies showed accumulation of Arildone in the stratum corneum. The concentration of Arildone in the viable epidermis was estimated from sectioning the skin and was found to be in sufficient amounts (400 µg cm^–3) to have potential antiviral activity. Conclusions. The apparent accumulation of Arildone in the stratum corneum suggested that the hydrophilic skin region presented the main barrier to permeation. Azone which affected the permeability of the stratum corneum was therefore not effective at enhancing Arildone absorption. Vehicles which readily permeate and enhance the transfer of lipophilic drugs from the stratum corneum into the viable epidermis were recommended.