Transdermal delivery of piroxicam using microemulsions

To improve the skin permeability of piroxicam, a new oil-in-water microemulsion containing 0.5% piroxicam was developed. Among various oils investigated for their suitability as an oil phase for the microemulsion system, oleic acid showed both excellent solubility and skin permeation enhancing effect for piroxicam. Microemulsion existence ranges were identified through the construction of the pseudo-ternary phase diagram. The effect of the content of oleic acid and the ratio of the surfactant/cosurfactant on skin permeation of piroxicam were evaluated with excised rat skins. The optimum formulation with the highest skin permeation rate (47.14 microg/cm2/h) consisted of 0.5% piroxicam, 10% oleic acid, 60% Labrasol/ethanol (1:5) and water.     

Microemulsion and poloxamer microemulsion-based gel for sustained transdermal delivery of diclofenac epolamine using in-skin drug depot: In vitro/in vivo evaluation

Microemulsion (ME) and poloxamer microemulsion-based gel (PMBG) were developed and optimized to enhance transport of diclofenac epolamine (DE) into the skin forming in-skin drug depot for sustained transdermal delivery of drug. D-optimal mixture experimental design was applied to optimize ME that contains maximum amount of oil, minimum globule size and optimum drug solubility. Three formulation variables; the oil phase X₁ (Capryol^®), Smix X₂ (a mixture of Labrasol^®/Transcutol^®, 1:2 w/w) and water X₃ were included in the design. The systems were assessed for drug solubility, globule size and light absorbance. Following optimization, the values of formulation components (X₁, X₂, and X₃) were 30%, 50% and 20%, respectively. The optimized ME and PMBG were assessed for pH, drug content, skin irritation, stability studies and ex vivo transport in rat skin. Contrary to PMBG and Flector^® gel, the optimized ME showed the highest cumulative amount of DE permeated after 8 h and the in vivo anti-inflammatory efficacy in rat paw edema was sustained to 12 h after removal of ME applied to the skin confirming the formation of in-skin drug depot. Our results proposed that topical ME formulation, containing higher fraction of oil solubilized drug, could be promising for sustained transdermal delivery of drug.     

Transdermal delivery of levosimendan

The aim of this study was to determine if transdermal penetration of levosimendan, a novel positive inotropic drug, could be enhanced and controlled by formulation modifications. Penetration of levosimendan across human epidermis in vitro was determined using abdominal excised skin and diffusion cells. Predicted steady-state plasma concentrations of levosimendan were estimated using permeabilities and pharmacokinetic parameters of levosimendan. For penetration enhancement we used different pH values, co-solvents, cyclodextrins, surfactants, penetration enhancers, liposomes, and iontophoresis. Sodium lauryl sulfate, ethanol, oleic acid, and soya phosphatidylcholine or their combinations clearly increased levosimendan permeation across the skin in vitro. Iontophoresis was also an efficient method to increase transdermal permeation of levosimendan. A hydrophilic co-solvent/penetration enhancer is needed to achieve better permeability of levosimendan across the skin. In conclusion, transdermal delivery of levosimendan can be significantly increased by formulation modification. Based on kinetic calculations, therapeutic plasma concentrations may be achievable transdermally.     

Transdermal delivery of ketoprofen using microemulsions

A transdermal preparation containing ketoprofen was developed using O/W microemulsion system. Of the oils tested, oleic acid was chosen as the oil phase of the microemulsion, as it showed a good solubilizing capacity and excellent skin permeation rate of the drug. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant and cosurfactant for microemulsion formation, and the effect of these additives on skin permeation of ketoprofen was evaluated with excised rat skins. The optimum formulation of the microemulsion consisted of 3% ketoprofen, 6% oleic acid, 30% Labrasol/Cremophor RH 40 (1:1) and water. Terpenes were added to the microemulsion at the level of 5% and their effect on the skin permeation of ketoprofen from the microemulsion was evaluated. Of the four terpenes used, only limonene resulted in a powerful enhancing activity (3-fold increase over control).     

双氯灭痛凝胶的透皮试验

用高效液相色谱法测定了双氯灭痛凝胶在离体兔皮肤的透皮吸收率。实验结果表明,24h累积渗透率为30.16％±2.81。     

Transdermal iontophoresis of ranitidine: an opportunity in paediatric drug therapy

The objective of this study was to examine the use of transdermal iontophoresis for the delivery of ranitidine hydrochloride in children. Constant, direct current, anodal iontophoresis of ranitidine was performed in vitro across dermatomed pig skin. The effect of donor vehicle, current intensity, and drug concentration were first examined using aqueous solutions. It was found that drug delivery was higher at pH 7 (donor: 5 mM Tris) than pH 5.6 (donor: water). In the presence of low levels of competing background electrolyte, ranitidine delivery increased linearly with applied current but was independent of the donor drug concentration. The second part of the study evaluated two Pluronic^® F-127 gels as potential vehicles for ranitidine delivery. The formulations were characterised in terms of apparent viscosity, conductivity and passive permeation measurements. Iontophoretic delivery of ranitidine was only slightly affected when delivered from the gels relative to aqueous solutions. Overall the results demonstrated that therapeutic paediatric doses of ranitidine (neonates: 0.09–0.17 μmol/kg h; 1 month to 12 years: 0.36–0.71 μmol/kg h) could be easily achieved by transdermal iontophoresis with simple gel patches of practical surface area (0.2–1.5 cm²/kg).     

Transdermal iontophoretic delivery of selegiline hydrochloride,in vitro

Transdermal iontophoretic delivery of selegiline hydrochloride (SH) across dermatomed human skin was studied. Electrochemical stability and various factors affecting the skin permeation were investigated. SH was stable under the influence of an electrical field. The permeation of SH was very low by passive delivery (2.29?±?0.05 μg/cm²/h) as compared to iontophoresis at 0.5 mA/cm² (65.10?±?5.04 μg/cm²/h). An increase in drug concentration from 1 to 20?mg/mL increased the iontophoretic flux by 13-fold. Optimal pH and salt (NaCl) concentration for iontophoretic delivery of SH were found to be pH 5 and 100?mM, respectively. Overall, with 20?mg/mL SH and a current density of 0.4 mA/cm², a maximum flux of 305.5?μg/cm²/h was obtained. Based on reported pharmacokinetic parameters, input target delivery rate to achieve effective plasma concentration of SH (2.2?ng/mL) was calculated. With a surface area of 40?cm², iontophoretic delivery can provide six to seven times higher levels of SH than the target delivery rate, which enables lowering of the dose and/or patch surface area. Further in vivo studies will be required to prove the efficacy of ionophoresis for enhanced delivery of SH.     

Transdermal delivery system of triamcinolone acetonide from a gel using phonophoresis

Triamcinolone acetonide (TA) is a corticosteroid that is used in the systemic and topical treatment of many inflammatory diseases. In this study, a phonophoretic drug delivery system was designed to enhance the TA permeability and the influence of ultrasound was examined. In order to establish the transdermal delivery system for TA, a hydrophilic carbopol gel containing TA was prepared after adopting phonophoresis. A permeation study through mouse skin was performed at 37 degrees C using a Franz diffusion cell, and the ultrasound treatment was carried out for 10 h. The level of TA permeation through the skin was evaluated under various ultrasound conditions including the frequency (1.0, 3.0 MHz), intensity (1.0, 2.5 W/cm2), and duty cycle (continuous, pulse mode) using a 0.5% TA gel. The highest permeation was observed under the ultrasound treatment conditions of low frequency, high intensity, and in continuous mode.     

苦参碱微乳水凝胶的质量评价及透皮研究

摘 要 目的：考察苦参碱微乳水凝胶（MBH）的质量及其透皮性能,为苦参碱制剂的研发提供依据。 方法: 在4℃条件下放置3个月,考察MBH的稳定性,主要观察MBH粒子外观、黏度、pH、苦参碱含量等指标的变化。以小鼠离体皮肤为模型,采用双室渗透扩散装置考察MBH的经皮渗透情况。以家兔为实验对象,考察MBH对正常皮肤和受损皮肤的刺激性。结果: 苦MBH在4℃条件下放置3个月后,其粒子外观、黏度、pH及苦参碱含量未发生明显变化。体外透皮实验表明,MBH对小鼠皮肤的渗透速率良好,单次或多次给药后无皮肤刺激性。结论:MBH具有良好的稳定性,透皮速率高,皮肤刺激性小,是一个具有开发应用前景的苦参碱经皮给药体系。     

Transdermal permeation of selegiline from hydrogel-membrane drug delivery systems

In the present work, we attempted to design a transdermal system for delivering selegiline using a hydrogel-based drug reservoir and a rate-controlling membrane (Solupor polyethylene membranes). The appearances of these preparations were evaluated by scanning electron microscopy (SEM), and the in vitro skin permeation of selegiline across porcine skin was examined. Both the R- and S-forms of selegiline were examined in this study to elucidate the stereoselectivity of skin to selegiline. Solupor membranes and hydrogels exhibited a cross-linking structure with micropores. R-Selegiline revealed a flux of 1.13 μg/cm²/h across porcine skin. Solupor membranes were rate limiting for skin permeation of selegiline. Around a 2-fold reduction in the drug flux was determined after Solupor membrane incorporation. There were no significant differences in drug flux across the four Solupor membranes tested. The flux of R-selegiline from cellulose hydrogels approximated that from the aqueous solution (control). Both the membrane and hydrogel greatly reduced the inter-subject variations in skin permeation. According to the results of skin permeation and the partition coefficient between the skin and water (log P_skin/water), the S-enantiomer may be preferable for permeation into the skin. However, the R- and S-forms demonstrated equal absorption of the drug fluxed in the presence of the membrane and/or the hydrogel. The results of this study encouraged us to further investigate hydrogel-membrane delivery systems for transdermal selegiline administration.     

蛇床子素微乳的制备及其透皮能力的研究

目的:制备蛇床子素微乳,并考察其对离体小鼠皮肤的透皮能力。方法:通过测定蛇床子素在不同油相、乳化剂和助乳化剂中的溶解度,结合伪三元相图筛选空白微乳的处方。考察蛇床子素微乳的黏度、电导率和粒径;用药物渗透扩散仪测定蛇床子素微乳的透皮速率。结果:制得的蛇床子素微乳的黏度为8.07mpa·s,电导率为123μS·cm-1,平均粒径为58.0nm。微乳中药物经小鼠皮肤的稳态渗透速率为(33.042±3.1)μg·cm-2·h-1(r=0.9950),是蛇床子素饱和溶液稳态渗透速率的25.5倍。结论:蛇床子素微乳有很强的透皮能力,有望成为蛇床子素的新型透皮给药制剂。     

氮酮对双氯灭痛透皮吸收作用的研究

本实验采用简单小室法,以离体小白鼠皮肤为透皮屏障,用生理盐水为接受液,研究了不同浓度的氮酮对双氯灭痛透皮吸收的影响。实验结果表明:含2%、1.5%、1.0%、0.5%氮酮的双氯灭痛擦剂与不含氮酮的双氯灭痛擦剂间,其透皮吸收有极显著性差异(P<0.01);含不同浓度氮酮的双氯灭痛擦剂间,其透皮吸收有显著性差异(P<0.05);其中以含1.5%氮酮的双氯灭痛擦剂,其透皮吸收为最好。     

Nanoparticles and microparticles for skin drug delivery

Skin is a widely used route of delivery for local and systemic drugs and is potentially a route for their delivery as nanoparticles. The skin provides a natural physical barrier against particle penetration, but there are opportunities to deliver therapeutic nanoparticles, especially in diseased skin and to the openings of hair follicles. Whilst nanoparticle drug delivery has been touted as an enabling technology, its potential in treating local skin and systemic diseases has yet to be realised. Most drug delivery particle technologies are based on lipid carriers, i.e. solid lipid nanoparticles and nanoemulsions of around 300 nm in diameter, which are now considered microparticles. Metal nanoparticles are now recognized for seemingly small drug-like characteristics, i.e. antimicrobial activity and skin cancer prevention. We present our unpublished clinical data on nanoparticle penetration and previously published reports that support the hypothesis that nanoparticles > 10 nm in diameter are unlikely to penetrate through the stratum corneum into viable human skin but will accumulate in the hair follicle openings, especially after massage. However, significant uptake does occur after damage and in certain diseased skin. Current chemistry limits both atom by atom construction of complex particulates and delineating their molecular interactions within biological systems. In this review we discuss the skin as a nanoparticle barrier, recent work in the field of nanoparticle drug delivery to the skin, and future directions currently being explored.     

Development of udenafil-loaded microemulsions for intranasal delivery: in vitro and in vivo evaluations

To achieve rapid onset of action and improved bioavailability of udenafil, a microemulsion system was developed for its intranasal delivery. Phase behavior, particle size, transmission electron microscope (TEM) images, and the drug solubilization capacity of the microemulsion were investigated. A single isotropic region was found in pseudo-ternary phase diagrams developed at various ratios with CapMul MCM L8 as an oil, Labrasol as a surfactant, and Transcutol or its mixture with ethanol (1:0.25, v/v) as a cosurfactant. Optimized microemulsion formulations with a mean diameter of 120-154 nm achieved enhanced solubility of udenafil (>10 mg/ml) compared with its aqueous solubility (0.02 mg/ml). An in vitro permeation study was performed in human nasal epithelial (HNE) cell monolayers cultured by the air-liquid interface (ALI) method, and the permeated amounts of udenafil increased up to 3.41-fold versus that of pure udenafil. According to the results of an in vivo pharmacokinetic study in rats, intranasal administration of udenafil-loaded microemulsion had a shorter T_max value (1 min) compared with oral administration and improved bioavailability (85.71%) compared with oral and intranasal (solution) administration. The microemulsion system developed for intranasal administration may be a promising delivery system of udenafil, with a rapid onset of action and improved bioavailability.     

盐酸奥丹西酮离子导入的研究(英)

本文研究了奥丹西酮在不同电流密度下经小鼠全皮的渗透动力学。当电流密度从0.05mA．cm-2升高到0.3mA．cm-2时，药物的稳态流量从30．29μg．cm-2.h-1增加到160.70μg．cm-2.h-1。研究中药物稳态流量和应用电流之间不严格呈线性关系。铂在供药池中作阳极时，可导致药物溶液变色；而应用银电极代替铂电极，则可以避免此问题的出现。应用铂电极时，供药池和接受池中均发现有pH变化。文章对以上问题以及解决的方法进行了讨论。     

盐酸罂粟碱 卵磷脂微乳的制备与透皮吸收

［摘要］目的探讨以卵磷脂微乳为载体，制备盐酸罂粟碱 卵磷脂微乳透皮给药系统，促进盐酸罂粟碱的透皮吸收。方法以伪三元相图考察油包水型微乳形成区域;以十四酸异丙酯 卵磷脂 乙醇 水作为微乳的组成部分，正交分析法筛选微乳处方，测定微乳黏度;采用智能透皮仪，大鼠离体皮肤作为透皮模型，与盐酸罂粟碱水溶液及盐酸罂粟碱 卵磷脂混悬液对比，用高效液相色谱（HPLC）法测定微乳中盐酸罂粟碱经皮渗透稳态流量。结果微乳各组分及比例对微乳粒径均有影响；盐酸罂粟碱 卵磷脂微乳的经皮渗透稳态流量大于对照组。结论微乳各组分及比例对微乳体系处方的选择具有重要意义；以微乳为载体可以促进盐酸罂粟碱的经皮渗透。     

Transdermal and transbuccal drug delivery systems: enhancement using iontophoretic and chemical approaches

We investigated the enhancement effect of chemical enhancers and iontophoresis on the in vitro transdermal and transbuccal delivery of lidocaine HCl (LHCl), nicotine hydrogen tartrate (NHT), and diltiazem HCl (DHCl) using porcine skin and buccal tissues. Dodecyl 2-(N,N-dimethylamino) propionate (DDAIP), dodecyl-2-(N,N-dimethylamino) propionate hydrochloride (DDAIP HCl), N-(4-bromobenzoyl)-S,S-dimethyliminosulfurane (Br-iminosulfurane), and azone (laurocapram) were used as chemical enhancers. The study results showed that the application of iontophoresis at either 0.1 mA or 0.3 mA significantly enhanced transdermal and transmucosal delivery of LHCl, NHT and DHCl. It was also demonstrated that iontophoresis had a more pronounced enhancement effect on transdermal delivery than on transbuccal delivery of LHCl, NHT and DHCl. In addition, DDAIP HCl was found to be the most effective enhancer for transbuccal delivery of LHCl and NHT.     

油酸微乳对利多卡因透皮吸收的影响

目的研究油酸微乳对利多卡因透皮吸收的影响。方法在制备相图的基础上，考察了微乳的组分对微乳形成的影响。选择适当的表面活性剂/助表面活性剂比例，制备利多卡因的油酸微乳处方，考察微乳、乳剂、胶束和饱和水溶液在透皮吸收方面的差异。结果以Labrasol为表面活性剂，吐温80为助表面活性剂所得油酸微乳的区域较大，微乳对利多卡因有明显的促透作用，透皮速率依次为微乳＞乳剂＞饱和水溶液＞胶束。结论油酸微乳可促进利多卡因的透皮吸收。     

Diclofenac systemic exposure is not increased when topical diclofenac is applied to ultraviolet-induced erythema

Objectives Diclofenac is a non-steroidal anti-inflammatory drug used for a variety of painful and inflammatory conditions. A new low-dose, topical-gel form of diclofenac sodium (diclofenac-Na) has been developed for pain relief and redness reduction after sunburn. The objective was to compare exposure to oral diclofenac-Na with the systemic exposure to diclofenac after application of the new topical diclofenac-Na 0.1% Emulgel gel (diclofenac-Na gel) to normal skin and to that with ultraviolet-induced erythema relative. Methods This study was an open, single-centre, three-period, non-randomised trial in 18 healthy Caucasian subjects. During the first period, 12.5 g gel (12.5 mg diclofenac-Na) was applied twice on a single day to normal skin. During the second period, a 25-mg diclofenac-Na, enteric-coated tablet was given orally three times in a single day. During the third period, the diclofenac-Na gel was applied, as in the first period, but during the early phase of an erythema induced by three times the ultraviolet minimal erythema dose, i.e. a first-degree sunburn associated with pain. During each period, venous blood samples were collected over 24 h and urine was collected over 72 h after first administration for the determination of diclofenac in plasma and urine and of 4-OH-diclofenac in urine. Results The systemic exposure after topical application of 25 mg diclofenac-Na on sunburned skin was less than 3% that of 75 mg oral diclofenac-Na and was not increased to that measured on normal skin. Conclusion The diclofenac-Na 0.1% Emulgel gel can be applied safely to sunburned skin (superficial sunburn, i.e. first degree) as well as to normal skin.