Skin Penetration and Metabolism of Topical Glucocorticoids in Reconstructed Epidermis and in Excised Human Skin

Purpose. To investigate pharmacokinetic differences between the non-halogenated double ester prednicarbate (PC) and the fluorinated monoester betamethasone 17-valerate (BM17V) their metabolism in human keratinocytes and fibroblasts as well as their permeation and biotransformation in reconstructed epidermis and excised human skin was compared. Special attention was given to the 17-monoesters because of their high receptor affinity and antiproliferative effects. Methods. Glucocorticoid penetration was determined using Franz diffusion cells, quantifying metabolite concentrations by HPLC. Chemical stability and reactivity of the monoesters was determined by molecular modeling analysis. Results. PC accumulated in the stratum corneum. A considerable amount of penetrating PC was hydrolyzed by viable keratinocytes to prednisolone 17-ethylcarbonate (P17EC). P17EC permeated the skin very rapidly when compared to BM17V. Overall P17EC concentrations in viable tissue were low. Inside of the acceptor fluid, but not within the tissue, P17EC was converted to the more stable prednisolone 21-ethylcarbonate (P21EC). Conclusions. The inactivation of highly potent, but also cell toxic, 17-monoesters to almost inactive 21-congeners seen with isolated cell monolayers appears less important in the skin. In vitro determination of the dermal 17-monoesters concentrations may allow the prediction of the atrophogenic risk in man. BM17V levels exceeding P17EC concentrations about 6-fold may contribute to its lower tolerance when compared to PC.     

Varian直线加速器全碳纤维治疗床对放疗剂量的影响

目的:探讨Varian直线加速器全碳纤维治疗床对放疗剂量的影响。方法:将固体水模置于主床板、衔接处、延长板的中心处,改变机臂角度,从不同角度让不同能量的高能X射线穿透治疗床,通过对比测量计算出穿透因子。利用放射治疗计划系统设计加床和不加床的计划,测量绝对剂量的误差。结果:6、15 MV X线,主床板和延长板的穿透因子在机架角105～120°区间较低,主床板在115°时最小,穿透因子分别为0.954 4、0.968 5;延长板在110°时最小,穿透因子分别为0.914 7、0.924 7;衔接处的穿透因子远小于主床板和延长板,120°时最小,分别为0.484 8、0.586 0。利用TPS设计放射治疗计划加虚拟床后,实测剂量更接近计划中的计算值。结论:随着床板厚度的增加,穿透因子减小;主床板和延长板对剂量的衰减接近,衔接处衰减最大,摆位时应避免射野穿过;能量越高,穿透因子越大;在设计放射治疗计划时,加虚拟床是必要的。     

不同透皮吸收促进剂对复方水杨酸凝胶透皮作用的影响

目的：探讨不同的促进剂对复方水杨酸凝胶透皮吸收的影响。方法：配制含不同促进剂的复方水杨酸凝胶，采用简单扩散小室装置，用紫外分光光度法测定不同处方凝胶剂中水杨酸和苯甲酸的透皮吸收药量。结果：水杨酸和苯甲酸的累积透皮吸收百分率与时间呈线性关系。与不合吸收促进荆的凝胶比较，吸收促进剂对水杨酸和苯甲酸透皮吸收的影响为薄荷脑＋油酸〉薄荷脑〉薄荷脑＋月桂氮[艹卓]酮〉油酸〉不合促渗剂〉软膏剂〉月桂氮[艹卓]酮。结论：薄荷脑，油酸对复方水杨酸凝胶的透皮吸收有明显的促进作用，其中以薄荷脑＋油酸的作用最明显，单独使用月桂氮[艹卓]酮对复方水杨酸凝胶剂有抑制作用。     

兔眼准分子激光原位角膜磨镶术后托吡卡胺滴眼前房浓度的改变

目的探讨准分子激光原位角膜磨镶术(LASIK)对托吡卡胺角膜通透性的影响。方法 24只新西兰白兔24只眼施行LASIK手术,于术前和术后30 d测量并比较1%托吡卡胺滴眼液扩瞳后10、15、30 min以及1、2h时的瞳孔大小,记录瞳孔达到6.0 mm大小所需时间,高效液相色谱法(HPLC)测量扩瞳后15 min托吡卡胺的房水浓度。结果术后30 d 1%托吡卡胺滴眼液扩瞳后15、30 min及1 h时的瞳孔直径明显大于术前对应时间点的瞳孔大小,而10 min以及2 h时的瞳孔大小无显著性差别;瞳孔达到6.0 mm大小所需平均时间由术前(16.40±4.28)min减少至(14.06±2.36)min;术后30 d托吡卡胺的房水浓度高于术前对应时间点。结论 LASIK术后托吡卡胺的前房浓度增加。LASIK导致的角膜生理特性的改变增强了托吡卡胺的角膜通透性。     

Reverse Hexagonal Phase Nanodispersion of Monoolein and Oleic Acid for Topical Delivery of Peptides: in Vitro and in Vivo Skin Penetration of Cyclosporin A

Purpose To obtain and characterize reverse hexagonal phase nanodispersions of monoolein and oleic acid, and to evaluate the ability of such system to improve the skin penetration of a model peptide (cyclosporin A, CysA) without causing skin irritation. Methods The nanodispersion was prepared by mixing monoolein, oleic acid, poloxamer, and water. CysA was added to the lipid mixture to obtain a final concentration of 0.6% (w/w). The nanodispersion was characterized; the skin penetration of CysA was assessed in vitro (using porcine ear skin mounted in a Franz diffusion cell) and in vivo (using hairless mice). Results The obtainment of the hexagonal phase nanodispersion was demonstrated by polarized light microscopy, cryo-TEM and small angle X-ray diffraction. Particle diameter was 181.77 ± 1.08 nm. At 0.6%, CysA did not change the liquid crystalline structure of the particles. The nanodispersion promoted the skin penetration of CysA both in vitro and in vivo. In vitro, the maximal concentrations (after 12 h) of CysA obtained in the stratum corneum (SC) and in the epidermis without stratum corneum (E) + dermis (D) were ∼2 fold higher when CysA was incorporated in the nanodispersion than when it was incorporated in the control formulation (olive oil). In vivo, 1.5- and 2.8-times higher concentrations were achieved in the SC and [E+D], respectively, when the nanodispersion was employed. No histopathological alterations were observed in the skin of animals treated with the nanodispersion. Conclusion These results demonstrate that the hexagonal phase nanodispersion is effective in improving the topical delivery of peptides without causing skin irritation.     

粗茎秦艽醇提物体内外经皮渗透性研究

目的建立粗茎秦艽Gentianacrassicaulis透皮吸收液中多种环烯醚萜类化学成分含量测定方法,并对粗茎秦艽体内外经皮渗透特性进行研究,为粗茎秦艽经皮给药制剂的研发、临床用药和传统剂型改革提供科学依据。方法在课题组前期研究的基础上,采用醇提法制备粗茎秦艽提取液,选用3种常用的透皮促渗剂氮酮、冰片和丙二醇,利用HPLC定量评价单一促渗剂或二元复合促渗剂对粗茎秦艽中马钱苷酸、山栀苷甲酯、獐芽菜苦苷、龙胆苦苷和獐芽菜苷5种主要成分的体外经皮渗透特性的影响;以龙胆苦苷、马钱苷酸和獐芽菜苦苷3种成分为评价指标研究粗茎秦艽醇提物在活体小鼠皮肤模型的渗透特性。结果与对照组相比,促渗剂的使用可显著增加粗茎秦艽中5种主要成分的体外吸收,A(5%氮酮)、B(5%冰片)、C(5%丙二醇)、A+B(2.5%氮酮+2.5%冰片)、A+C(2.5%氮酮+2.5%丙二醇)、B+C(2.5%冰片+2.5%丙二醇)5组中马钱苷酸、山栀苷甲酯、獐芽菜苦苷、龙胆苦苷和獐芽菜苷的透皮吸收速率(J)分别可达12.306 0、1.248 8、4.187 5、153.0300、5.0126μg/(cm~2·h),促渗效果分别是对照组的9.73、2.57、13.94、15.92、8.08倍。其中,A+C组,即2.5%氮酮+2.5%丙二醇组体外促渗效果最为明显。体内经皮渗透实验表明,与空白组对比,2.5%氮酮+2.5%丙二醇组对于活体小鼠皮肤的促渗透效果表现较好。结论氮酮和丙二醇对粗茎秦艽中马钱苷酸、山栀苷甲酯、獐芽菜苦苷、龙胆苦苷和獐芽菜苷5种主要成分有良好的促渗透效果,为研究粗茎秦艽经皮给药制剂质量控制奠定基础。     

促渗剂对茶多酚搽剂体外经皮渗透的影响

目的：考察促渗剂氮酮和丙二醇对茶多酚搽剂体外经皮渗透的影响,为该制剂的组方提供实验依据。方法：采用小鼠离体皮肤作为渗透屏障,以茶多酚中主要活性成分表没食子儿茶素没食子酸酯（EGCG）为检测指标,采用HPLC测定,研究氮酮和丙二醇对茶多酚的促渗作用。结果：含2%氮酮和10%丙二醇的1%茶多酚搽剂、含2%氮酮的1%茶多酚搽剂以及含10%丙二醇的1%茶多酚搽剂24h累积渗透量分别为不含促渗剂的1%茶多酚搽剂的5.86,5.02和1.18倍。结论：10%丙二醇对茶多酚搽剂具有一定的促渗作用,2%氮酮促渗效果显著,二者联合使用对茶多酚搽剂的促渗效果最好,其渗透动力学行为可用Higuchi方程描述。     

丙二醇-肉豆蔻酸异丙酯系统中促透剂对来曲唑经皮透过性的影响

目的考察在丙二醇(propylene glycol,PG)-肉豆蔻酸异丙酯(isopropyl myristate,IPM)系统(简称PI系统)中经皮促透剂对来曲唑经皮透过性的影响。方法采用水平双室扩散池,以离体大鼠皮肤作为透过屏障进行体外透过实验。结果在不含经皮促透剂时,来曲唑的累积透过量随体系中PG浓度的增加而增大。在PI系统[m(PG)∶m(IPM)=20∶100]中,N-甲基-2-吡咯烷酮、月桂氮卓酮、乳酸对来曲唑的透过具有显著的促进作用,司盘-80和二乙二醇单乙基醚具有轻微抑制作用,而油酸和吐温-80则有显著的抑制作用。结论在PI系统中经皮促透剂对来曲唑的经皮透过性具有不同的促透作用,为开发来曲唑的透皮给药贴剂提供参考数据。     

Skin penetration behaviour of sesquiterpene lactones from different Arnica preparations using a validated GC-MSD method

Preparations of Arnica montana L. are widely used for the topical treatment of inflammatory diseases. The anti-inflammatory activity is mainly attributed to their sesquiterpene lactones (SLs) from the helenalin and 11alpha,13-dihydrohelenalin type. To study the penetration kinetics of SLs in Arnica preparations, a stripping method with adhesive tape and pig skin as a model was used. For the determination of SLs in the stripped layers of the stratum corneum (SC), a gas chromatography/mass spectrometry method was developed and validated. Thereby the amount of helenalin derivatives was calculated as helenalin isobutyrate, and 11alpha,13-dihydrohelenalin derivatives as 11alpha,13-dihydrohelenalin methacrylate. This GC-MSD method is suitable also to determine low amounts of SLs in Arnica preparations. The penetration behaviour of one gel preparation and two ointment preparations was investigated. The SLs of all preparations show a comparable penetration in and a permeation through the stratum corneum, the uppermost part of the skin. Interestingly, the gel preparation showed a decrease of the penetration rate over 4h, whereas the penetration rate of ointments kept constant over time. Moreover, we could demonstrate that the totally penetrated amount of SLs only depends on the kind of the formulation and of the SLs-content in the formulation but not on the SLs composition or on the used extraction agent.     

Complexation of the sunscreen agent, 4-methylbenzylidene camphor with cyclodextrins: effect on photostability and human stratum corneum penetration

The interaction between the sunscreen agent, 4-methylbenzylidene camphor (4-MBC) and hydrophilic alpha-, beta- and gamma-cyclodextrin derivatives was investigated in water by phase-solubility analysis. Among the studied cyclodextrins, random methyl-beta-cyclodextrin (RM-beta-CD) had the greatest solubilizing activity. The complexation of the sunscreen agent with RM-beta-CD was confirmed by nuclear magnetic resonance spectroscopy and powder X-ray diffractometry. The light-induced decomposition of 4-MBC in emulsion vehicles was markedly decreased by complexation with RM-beta-CD (the extent of degradation, determined by HPLC, was 7.1% for the complex compared to 21.1% for free 4-MBC). The influence of RM-beta-CD on the human skin penetration of the sunscreen was investigated in vivo using the tape stripping method, a useful procedure for selectively removing the outermost cutaneous layers. Considerable quantities (21.2-25.1% of the applied dose) of 4-MBC permeated in the stratum corneum. However, no significant differences in the amounts of UV filter in the 10 first strips of the horny layer were observed between the formulations containing 4-MBC free or complexed with RM-beta-CD. Therefore, RM-beta-CD complexation did not alter the retention of 4-MBC in the superficial layers of the stratum corneum, where its action is more desirable.