Effect of vehicles and penetration enhancers on the in vitro percutaneous absorption of celecoxib through human skin

The aim of this study was the comparison of three different formulations (gel, o/w emulsion, oleagenous cream) and two penetration enhancers (oleic acid and menthol) as vehicle systems for celecoxib in respect of release and penetration through excised human skin in vitro. The influence of the vehicle on the release rate was studied in vitro using a cellulose acetate membrane. The release rate could be increased by up to 6.5 and 2.5 times with gel and o/w emulsion compared to oleagenous cream respectively. Further in vitro penetration measurements using human skin on Franz diffusion cells were performed with and without oleic acid and menthol as enhancers. It was shown that the penetration rate is strongly dependent upon the enhancer type and concentration but not on the vehicle itself and could be increased by 48% when 5% oleic acid was used in oleagenous cream. In all formulations tested, celecoxib was released and penetrated into human skin more quickly and to a greater extent from the gel formulations. There is no topical formulation available of celecoxib and its penetration properties through human skin have not been investigated. Since celecoxib creates some gastrointestinal disturbances, topical formulations of celecoxib preferably in gel form including 5% oleic acid could be suggested as an alternative.     

Effect of vehicles and penetration enhancers on the in vitro percutaneous absorption of tenoxicam through hairless mouse skin

The effects of vehicles and penetration enhancers on the in vitro permeation of tenoxicam from saturated solutions through dorsal hairless mouse skin were investigated. Various types of vehicles, including ester-, alcohol-, and ether-types and their mixtures, were used as vehicles, and then a series of fatty acids and amines were employed as enhancers, respectively. Even though the fluxes of tenoxicam from saturated pure vehicles were generally low (0.1-1.1 microg/cm2 per h), the skin permeability of tenoxicam was significantly increased by the combination of diethylene glycol monoethyl ether (DGME) and propylene glycol monolaurate (PGML) or propylene glycol monocaprylate (PGMC); the highest fluxes were achieved at 40% of DGME in both of the two cosolvents. The marked synergistic enhancement was also obtained by using propylene glycol (PG)-oleyl alcohol (OAl) cosolvent. The greatest flux was attained by the addition of unsaturated fatty acids at 3% concentration to PG. But saturated fatty acids failed to show a significant enhancing effect. The enhancement factors with the addition of oleic acid (OA) or linoleic acid (LOA) to PG were 348 and 238, respectively. Tromethamine (TM) showed an enhancing effect by the increased solubility; however, triethanolamine (TEA) did not show a significant enhancing effect. Rather, it decreased the fluxes of tenoxicam when added to PG with fatty acids. The above results indicate that the combinations of lipophilic vehicles like OA, LOA or OAl and hydrophilic vehicles like PG can be used for enhancing the skin permeation of tenoxicam.     

不同促渗剂对盐酸芦氟沙星体外经皮渗透的影响

目的　研究几种常用促渗剂对盐酸芦氟沙星体外经皮渗透的影响。方法　用紫外分光光度法检测浓度 ,采用改进Franz扩散池 ,比较几种常用促渗剂对盐酸芦氟沙星渗透系数的影响。结果　1%氮酮和 1%氮酮 10 %丙二醇可显著增大盐酸芦氟沙星的渗透系数 (P <0 .0 1)。结论　 1%氮酮和1%氮酮 10 %丙二醇可作为促渗剂用于盐酸芦氟沙星的透皮吸收制剂     

Effect of penetration enhancers on the transdermal delivery of bupranolol through rat skin

Bupranolol (BPL) is a suitable drug candidate for transdermal drug delivery system development based on its favorable physicochemical and pharmacokinetic properties. The effect of different penetration enhancers on the permeation of BPL across rat skin was studied using side-by-side diffusion cells. 2-Pyrrolidone (PY), 1-methyl-2-pyrrolidone (MPY), and propylene glycol (PG) at various concentrations were used as penetration enhancers along with 0.4% w/v aqueous suspension of BPL. Menthol at different concentrations in isopropanol-water (6:4) mixture also was used as an enhancer wherein BPL at 0.4% w/v was completely solubilized. Skin pretreatment studies were carried out with all the above enhancers to understand their role in the penetration enhancement effect. PY and MPY at 5% w/v concentrations increased the permeation of BPL by 3.8- and 2.4-fold, respectively, versus control (p < .01). PG at 10% and 30 w/v concentrations increased the flux of BPL by 2.5- and 5.0-fold, respectively, versus control (p < .001). Menthol at 2% w/v concentration increased the flux of BPL by 3.8-fold (p < .01) and further increase in menthol concentration significantly decreased the flux of BPL. Overall, pyrrolidones and menthol at low concentrations (5% w/v or less) and PG at 30% w/v concentration were effective as penetration enhancers for BPL.     

Effect of some enhancers on the permeation of haloperidol through rat skin in vitro

The objective of this work is to enhance the permeation of haloperidol through the rat skin in vitro by using various enhancers at a concentration of 1 mg/ml in the saturated drug solution and analysing the dose-dependent diffusion profile for the enhancers which significantly increased permeation at this concentration compared with the control. Enhancers belonging to various chemical classes like the vitamins (ascorbic acid), surfactants (cetrimide, polysorbate 20), sulfoxides (dimethyl sulfoxide), glycols (polyethylene glycol 400, propylene glycol) and amides (urea) were used. Amber glass Franz-type diffusion cells were used for the permeation studies and haloperidol was made soluble in aqueous solution with the aid of lactic acid. Ascorbic acid and cetrimide increased flux and permeability coefficient significantly. From the dose-dependent permeation studies, it was concluded that ascorbic acid enhanced the permeation by increasing the solubility of the drug in the vehicle thus providing a high concentration gradient across the skin, whereas cetrimide enhanced the permeation by increasing the thermodynamic activity which may be due to solubilization of skin lipids by micelles. Polysorbate 20 decreased the enhancer index by decreasing the thermodynamic activity. None of the enhancers changed the lag time except for urea which decreased the lag time probably by its binding with keratin. Dimethyl sulfoxide, polyethylene glycol 400 and propylene glycol did not have a significant effect on haloperidol permeation compared with control.     

促渗剂对咪喹莫特体外经皮渗透的影响

目的研究几种促渗剂对咪喹莫特体外经皮渗透的影响。方法采用水平扩散池、离体SD大鼠腹部皮肤用渗透剂预处理的方法,测定接收液中咪喹莫特的含量及皮肤中药物的滞留量。结果在考察的促渗剂中,除卡必醇外(P>0.05),油酸、丙二醇、异硬脂酸、氮酮、月桂酸、松节油对咪喹莫特都有促渗作用;油酸、异硬脂酸能显著提高药物在皮肤中的滞留量(P<0.01),油酸对透过量影响不大(P>0.05);氮酮能使透过量显著增大(P<0.01),质量分数为3%的氮酮并不影响皮肤中的滞留量(P>0.05);松节油能使经皮透过量和皮肤中的滞留量都有所增加(P<0.05)。结论选用异硬脂酸作为咪喹莫特的渗透促进剂,该促渗剂能在不增加皮肤透过量的同时增加药物在皮肤中的滞留量。     

Effect of pH and penetration enhancers on electroosmotic flow and flux through skin

We have investigated the effect of pH and four penetration enhancers on the electroosmotic volume flow (EVF) and flux through skin to get more detailed understanding of this phenomenon and its effect on flux. The results were evaluated in relation EVF and the permeability change by current induced skin damage. At pH 7.4, we have confirmed that the direction of convective solvent flow is from anode to cathode. At pH 4.0, no permselectivity was observed and it seems that this pH is close to the isoelectric point of skin. At pH 3.0, the permselectivity of skin is reversed. From the difference in flux between just before (47 μg/cm² h) and after (32 μg/cm² h) cathodal current-off, the magnitude of EVF is estimated to be smaller than 1.5 μl/cm² h, if we consider the recovery of skin to a lower permeability after current-off. At pH 7.4, Oleic acid (OA) and propylene glycol monolaurate (PGML) increased the passive flux markedly. Synergistic effect in flux between OA and current was observed for both anodal and cathodal current. The use of isopropyl myristate (IPM) in combination with anodal current resulted in reduced flux when compared to the flux of anodal current alone. Cathodal flux of OA or PGML treated skin increased continuously until the current was off. However, to the contrary of our expectation, flux decreased after current-off. We think this is mainly due to the recovery of damaged skin (flux decreasing effect), though the disappearance of EVF may slightly increase the flux. For IPM and propylene glycol, the combination of enhancer with cathodal current inhibited the flux, similar to that observed for anodal delivery. Overall, these results provide further information on the role of electroosmosis and the effect of penetration enhancers in combination with current on flux through skin.     

Effect of chemical enhancers on percutaneous absorption of daphnetin in isopropyl myristate vehicle across rat skin in vitro

The percutaneous absorption properties of daphnetin with chemical penetration enhancers were investigated to explore the feasibility of daphnetin as a candidate for transdermal delivery to treat arthritis. Permeation experiments were carried out in vitro using 2-chamber diffusion cells in isopropyl myristate (IPM) vehicle using rat abdominal skin as a barrier. Various enhancers were employed, including O-acylmenthol derivatives synthesized in the laboratory and many conventional enhancers. Among the O-acylmenthol derivatives, 2-isopropyl-5-methylcyclohexyl 2-hydroxypanoate (M-LA) demonstrated a significant enhancing effect on daphnetin permeation. The highest degree of enhancement was obtained when NMP combined with Span 80 and the cumulative transport was 667.29 μg/cm² over 8 h. The solubility parameters, vehicle/stratum corneum partition, and diffusion coefficients were calculated to clarify the enhancing mechanism of classic enhancers on daphnetin. In conclusion, these findings allow a rational approach for designing an effective daphnetin transdermal delivery system.     

Effect of vehicles and enhancers on thein vitro skin penetration of aspalatone and its enzymatic degradation across rat skins

The feasibility of skin penetration was studied for aspalatone (AM, acetylsalicylic acid maltol ester), a novel antithrombotic agent. In this study, hairless mouse dorsal skins were used as a model to select composition of vehicle and AM. Based on measurements of solubility and partition coefficient, the concentration of PG that showed the highest flux for AM across the hairless mouse skin was found to be 40%. The cumulative amount permeated at 48 h, however, appear inadequate, even when the PG concentration was employed. To identify a suitable absorption enhancer and its optimal concentration for AM, a number of absorption enhancers and a variety of concentration were screened for the increase in transdermal flux of AM. Amongst these, linoleic acid (LOA) at the concentration of 5% was found to have the largest enhancement factor (i.e., 132). However, a further increase in AM flux was not found in the fatty acid concentration greater than 5%, indicating the enhancement effect is in a bell-shaped curve. In a study of the effect of AM concentration on the permeation, there was no difference in the permeation rate between 0.5 and 1% for AM, below its saturated concentration. At the donor concentration of 2%, over the saturated condition, the flux of AM was markedly increased. A considerable degradation of AM was found during permeation studies, and the extent was correlated with protein concentrations in the epidermal and serosal extracts, and skin homogenates. In rat dorsal skins, the protein concentration decreased in the rank order of skin homogenate > serosal extract > epidermal extract. Estimated first order degradation rate constants were 6.1 5 +/- 0.14, 0.57 +/- 0.02 and 0.011 +/- 0.004 h(-1) for skin homogenate, serosal extract and epidermal extract, respectively. Therefore, it appeared that AM was hydrolyzed to some extent into salicylmaltol by esterases in the dermal and subcutaneous tissues of skin. Taken together, our data indicated that transdermal delivery of AM is feasible when the combination of PG and LOA is used as a vehicle. However, since AM is not metabolically stable, acceptable degradation inhibitors may be necessary to fully realize the transdermal delivery of the drug.     

Effect of some penetration enhancers on the permeation of glibenclamide and glipizide through mouse skin

The purpose of this investigation was to study the effect of some penetration enhancers on in vitro permeation of glibenclamide and glipizide through mouse skin. Ethanol in various concentrations, N-methyl-2-pyrrolidinone, transcutol, propylene glycol and terpenes like citral, geraniol and eugenol were used as penetration enhancers. The in vitro skin permeation experiments were conducted by both simultaneous application of drug and enhancer solution and by pretreatment of the skin with neat enhancer. At the end of the experiment drug retained in the skin was estimated. The flux values (microg/cm2/h) of both drugs significantly (p < 0.05) increased in the presence of penetration enhancers, except transcutol and propylene glycol. The glibenclamide flux values ranged from 1.42 +/- 0.09 without enhancer, to 18.25 +/- 1.21 in a combination of 50% ethanol and 5% eugenol. Glipizide flux values ranged from 3.21 +/- 0.51 without enhancer, to 57.21 +/- 5.25 in a combination of 50% ethanol and 5% eugenol. Skin retention and solubility of both drugs increased with all penetration enhancers compared to control (except propylene glycol). As the target permeation rates for glibenclamide and glipizide were calculated to be 193.8 and 184.8 microg/h respectively, the present study showed that the required permeation rates for both drugs could be achieved with the aid of enhancers by increasing the area of application in an appreciable range.     

Mechanism of in vitro percutaneous absorption enhancement of carvedilol by penetration enhancers

The effect of penetration enhancers like tulsi (basil) oil, eucalyptus oil, clove oil, black cumin oil, oleic acid and Tween 80 on the percutaneous absorption of model lipophilic drug-carvedilol was investigated using excised rat abdominal skin. Transdermal flux, permeability coefficient and enhancement factor were calculated for each penetration enhancer. Black cumin oil (5% v/v) was selected on the basis of its highest enhancement in permeation and was evaluated further for its mode of action using DSC, FTIR and histological studies. The results indicated that the oil shows its action by extraction of lipids from stratum corneum as well as by loosening the hydrogen bonds between ceramides subsequently leading to fluidization of the lipid bilayer.     

氢化可的松对酮康唑经大鼠皮肤透过性的影响

目的研究氢化可的松对酮康唑经大鼠皮肤透过性的影响。方法将12只♂Wistar大鼠随机分为两组,每组6只,分别设置为空白乳膏组和氢化可的松乳膏组,大鼠剃除腹部的毛后分别涂空白乳膏和氢化可的松乳膏,每天1次,连续给药两周(2 g·d-1)。给药结束后取下所有大鼠的腹部皮肤,采用改良的Franz扩散池法比较酮康唑乳膏经两组大鼠腹部皮肤的透过性差异,采用HPLC法检测样品中酮康唑的浓度,将浓度换算得到渗透速率。结果酮康唑乳膏经氢化可的松组大鼠腹部皮肤和空白乳膏组大鼠腹部皮肤的渗透速率分别为(0.403+0.026)和(0.730+0.042)μg·cm-2·h-1,两组实验结果差异有显著性(P<0.01)。结论♂Wistar大鼠腹部皮肤连续使用氢化可的松两周后,可能对皮肤组织产生了影响,从而引起酮康唑经皮透过的改变,导致酮康唑经皮透过量减少,渗透速率降低。这一结果提示,患者在使用氢化可的松乳膏后再使用其他经皮给药制剂时可能需考虑调整剂量。     

Effect of penetration enhancers on the permeation of mannitol, hydrocortisone and progesterone through human skin

Mannitol, hydrocortisone and progesterone were selected as model penetrants to assess the mode of action of eight potential penetration enhancers in human skin. Their partition coefficients, octanol: water and stratum corneum: water were measured and correlated with their postulated routes of penetration through human skin. The results suggest that mannitol penetrated via a polar route, hydrocortisone by a mainly lipid route and progesterone via a lipid pathway but its penetration rate was probably affected by aqueous layers. From permeation studies through cadaver skin in which an in-vivo mimic method was used, it was concluded that the penetration enhancers fell into three main categories: solvents which enhanced permeation of polar and non-polar compounds e.g. 2-pyrrolidone, N-methylpyrrolidone, N-methylformamide and propylene glycol plus Azone; enhancers which preferentially affected the polar route e.g. propylene glycol plus decylmethylsulphoxide, and accelerants which mainly modified the non-polar route e.g. propylene glycol plus oleic acid, propylene glycol alone and, to a limited extent, water.     

尼美舒利醇质体的体外经皮渗透特性及皮肤刺激性

目的:考察醇质体作为尼美舒利经皮给药载体的体外渗透性及刺激性。方法:采用注入法制备尼美舒利醇质体,采用Franz扩散池和鼠皮进行体外渗透实验,HPLC测定药物浓度并计算药物稳态透皮速率、12 h累积释放量及皮内滞留量;采用小鼠皮肤红斑平均积分考察尼美舒利醇质体刺激性。结果:测得尼美舒利醇质体的稳态经皮渗透速率和12 h累积释放量分别是(16.28±1.68)μg.(cm2.h)-1,(195.38±19.89)μg/cm2,与脂质体相比提高了1.9倍(P<0.05);而醇质体的皮内滞留量为(318.67±38.57)μg/cm2,仅是脂质体的1.07倍(P>0.05)。皮肤刺激性实验显示,NIM醇质体的红斑指数与生理盐水的差异并不明显(P>0.05)。结论:尼美舒利醇质体的经皮渗透性和皮肤刺激性都优于脂质体,是一种有效的经皮给药制剂。     

Enhanced penetration of mitomycin C through hairless mouse and rat skin by enhancers with terpene moieties

The effects of four new percutaneous absorption enhancers containing an azacyclo ring and terpene chain (1-geranylazacycloheptan-2-one (GAH), 1-farnesylazacycloheptan-2-one (FAH), 1-geranylazacyclopentan-2,5-dione (GAPD), and 1-farnesylazacyclopentan-2-one (FAP] and 1-dodecylazacycloheptan-2-one (Azone) on the percutaneous penetration of mitomycin C (MMC) through hairless mouse and rat skin in-vitro has been investigated. GAH, FAH, FAP and Azone enhanced MMC penetration by 20 to 60 times that of the control (ethanol). During the early part of the experiments, when the sink condition was maintained, FAH was the most effective for hairless mouse skin, whereas Azone showed the highest effect in the rat skin. The enhancing effect of GAPD was only about half that of the other enhancers, suggesting the importance of the polar group of the ring moiety in these compounds. The penetration of MMC through rat skin was also increased by pretreatment with these compounds, suggesting that the enhancers had a direct effect on the skin.     

不同透皮促进剂对马钱子碱体外透皮吸收的影响

目的考察不同透皮促进剂对马钱子碱体外透皮吸收的影响。方法采用改良Franz扩散池,选用离体猪耳朵皮为屏障,考察不同类型的透皮促进剂对马钱子碱体外透皮吸收速率、增渗倍数等参数的影响。结果除吐温-80外,各透皮促进剂均能提高马钱子碱的透皮速率,促透能力由弱至强依次为桉叶素<油酸<氮酮<肉豆蔻酸异丙酯<柠檬烯。结论本研究可为马钱子碱外用剂型的选择与优化提供指导。     

渗透促进剂对莫达芬尼透皮作用的影响

目的：研究10种渗透促进剂对莫达芬尼透皮吸收的影响。方法：采用改良的Franz扩散池，以40％PEG-400生理盐水溶液为接受介质，以大鼠离体腹部皮肤为透皮屏障，计算不同单元渗透促进剂作用下莫达芬尼累积渗透量Q、稳态流量Js及相关参数。结果：不同促渗剂对莫达芬尼有不同程度的促渗作用，氮酮、丁香油、月桂酸、薄荷醇对莫达芬尼促透作用比较显著，其增渗倍数分别是空白对照组的17．3850，16．3303，9．3297，8．7037倍。结论：此研究为莫达芬尼透皮吸收制剂处方的设计提供依据。     

Effect of counter-ions and penetration enhancers on the skin permeation of flurbiprofen

The aim of this work was to investigate the percutaneous absorption of flurbiprofen (FP) using counter-ions as enhancers as well as to compare their enhancing activity with penetration enhancers in vitro. The in vitro permeation studies of FP were performed in isopropyl myristate (IPM) solution by two-chamber diffusion cells, using rat abdominal skin as a model. Among the penetration enhancers examined, including the cosolvents of propylene glycol and ethanol (EtOH), oleic acid, menthol, laurocapram, sorbitan monooleate, and N-methyl-2-pyrrolidone (NMP), 10% (w/w) EtOH and NMP exhibited the most potent solubilization and enhancing effects of FP from IPM, with a flux of (372.60 ± 45.12) µg/cm²/h and (474.21 ± 46.64) µg/cm²/h, respectively. Ten percent (w/w) EtOH/IPM binary system was used to investigate the effect of the counter-ions, namely diethylamine (DEA), triethylamine (TEA), ethanolamine (EtA), diethanolamine (DEtA), triethanolamine (TEtA), and N-(2′-hydroxyethanol)-piperdine (HEPP). The cumulative amounts were markedly increased in the presence of the counter-ions, and the highest flux of (1297.53 ± 121.81) µg/cm²/h was obtained by DEA. This was related to the decreased lipophilicity and different physicochemical properties of the ion-pairs. In particular, we proved the formation of an FP/amine ion-pair in solution by ¹H-NMR. The results suggest that the counter-ions are more efficient than penetration enhancers. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1826–1837, 2010     

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。