Percutaneous absorption, metabolic profiling, and excretion of the penetration enhancer azone after multiple dosing of an azone-containing triamcinolone acetonide cream in humans

Radioactive Azone (1.6%; 1-dodecylazacycloheptan-2-one) was incorporated in a therapeutic formulation containing triamcinolone acetonide at a concentration of 0.05%. This cream (TAZ) was applied for four consecutive days to human volunteers on the same 24-cm2 application area on the forearm for 12 h under occlusion. The percutaneous absorption of Azone as measured in the excreta appeared to be only 3.47 +/- 0.33% during the whole study period. Azone-derived radioactivity was predominantly excreted by the kidneys (97.8 +/- 0.4%). From the urinary excretion plot, it could be deduced that the flux of Azone through human skin increased during the study period, reaching a plateau within 2-3 d. Accumulation of Azone in the stratum corneum did not occur. Only unchanged Azone could be detected in the stratum corneum. Excretion was mainly in the form of very polar metabolites. Compared with pure Azone, the therapeutic formulation did not influence the metabolism, excretion route, or urinary elimination rate of the penetration enhancer.     

Comparison of two in vitro methods to evaluate the water resistance of sunscreens

For a long time, the water resistance of sunscreens has been determined in vivo, according to Colipa's (Comité de Liaison des Industries de la Parfumerie) procedure. This method is not so ethical as healthy volunteers are irradiated, and can be replaced by an in vitro method which is easy and quick to perform. The objective of this work was to correlate the experimental device proposed by Choquenet et al. and the dissolutest (Sotax AT6). This equipment is used in the pharmaceutical industry to control the tablets. The experimental conditions have been fixed to correlate the results obtained with both methods. The stirring speed for the dissolutest was fixed at 75 rpm, which is the speed value recommended by the European Pharmacopeia to study the dissolution over time of tablets.     

两种定量分析法在成人-儿童转化中的应用

目的通过建立成人-儿童转化模型,为儿童临床用药提供指导性的建议,使得最大程度的减少儿童群体临床重复试验研究,降低儿童用药风险。方法以阿奇霉素为例,根据临床现有的成人药代动力学参数为基础,以儿童文献中的数据作为外部验证,对两种转化方法进行计算,得到参数的相对偏差和相对标准误差。结果通过异速模型、异速+成熟模型模拟出儿童相关的药代动力学参数,计算异速模型的ρ_(max)和t_(max)的相对偏差分别为-0.49、-0.23;相对标准误差分别为0.50、0.35。异速+成熟模型的ρ_(max)和t_(max)的相对偏差分别为-0.48、-0.13;相对标准误差分别为0.50、0.33。结论本研究仅仅是介绍了两种可行的转化思路,并不代表在所有药物临床试验前研究中都可行,要根据具体情况,建立可行的转化方法。     

Comparison of two methods to evaluate drug-cytotoxicity on tumor cell lines cultured in vitro

Some porphyrin compounds: P-NO2 and CVRIV were screened for cytotoxic activity against HT-29, LOVO, human tumor cell lines. The new radiometric assay was used for all cell lines. The soft agar cloning system was also utilized. The tested compounds decrease the growth index, measured in the radiometric assay, as 14CO2 production, and similarly depress the growth of tumor colonies on soft agar in the clonogenic assay. The cytotoxic effects of the compounds tested by these different methods were analysed statistically and resulted quantitatively similar. Based on these findings the radiometric assay represents a method, simple and rapid, which can be used as the clonogenic assay to screen new anticancer drugs.     

Comparison of in vitro model examinaitons with respect to drug release from suppositories

9 lipophilic suppository bases with different physical-chemical parameters were examined. Buspiron-hydrochloride, an anxiolytic drug with good water-solubility was used--partly as a model--as a pharmacon, in a concentration of 10.0 mg/2.00 g. The rate and extent of in vitro drug release was monitored with static and dynamic methods. Kidney-dialysing membranes with various surfaces were used. The quantitative measurements were carried out spectrophotometrically and the amount of the diffused drug was determined at lambda = 298 nm. The mean values were calculated from 5 parallel measurements each time. The percentage values of in vitro relative availability revealed that the results of the two static diffusion studies did not differ significantly (p < 0.05) and were almost independent of the size of the membrane surface. The results of the dynamic diffusion method were well-reproducible but were vehicle-dependent. The process of release was characterized by the mathematical transformation of the release curves, while the correlation coefficients described the closeness of the relation. Two German vehicles, namely Witepsol H 15 with a medium hydroxyl value and Massa Estarinum 299, and a French vehicle, Suppocire AS2X were found to be excellent for the formulation of suppositories containing Buspiron-hydrochloride.     

避蚊胺缓释霜剂的研制及其体外的经皮渗透

目的 制备避蚊胺缓释霜剂,并研究其体外经皮渗透情况.方法 用正交筛选法优化避蚊胺缓释霜剂的处方,采用HPLC法测定避蚊胺的含量.利用Franz扩散池,进行体外经皮渗透试验.结果 HPLC测定避蚊胺含量的回收率为101.6%,RSD=1.05%.避蚊胺缓释霜剂的体外渗透系数为0.0157 mg·cm-2·h-1,8 h累积渗透量为0.13 mg·cm-2.结论 避蚊胺缓释霜剂中避蚊胺的体外经皮渗透明显减慢,累积渗透量大大减少.     

Comparison of the response of psoriasis,over a 6-month period,to clobetasol propionate and fluocinolone acetonide ointments

Summary

Twenty-nine patients with bilateral psoriasis were treated with clobetasol propionate ointment on one side of the body and fluocinolone acetonide ointment on the other in a double-blind clinical trial lasting 6 months. With one exception, after the first month of treatment, all patients responded better on the clobetasol propionate treated side. There was a tendency for any relapses to be less rapid and less severe in clobetasol propionate treated lesions. No adverse effects from either steroid were observed.     

Effects of triamcinolone acetonide on leukocyte distribution in blood system, mononuclear liver infiltration, and immune response under conditions of stress-induced hypoxia in rats

The effect of triamcinolone acetonide (2 mg/kg) on the distribution of morphologically mature leukocytes in the blood system, the mononuclear liver infiltration, and the immune response was studied in rats under conditions of stress-induced hypoxia. Administered under these conditions, the drug produces a less pronounced effect on the content of circulating lymphocytes, the lymphoid cell number in the bone marrow, and the number of hepatocytes and monocytes/macrophages in the liver. However, the post-stressor immunodepressant effect of triamcinolone acetonide was increased and accompanied by the development of hepatic damage.     

复方甲硝唑克林霉素乳膏的皮肤刺激性、致敏试验及离体透皮释药特性

目的：制备复方甲硝唑克林霉素乳膏,并了解乳膏的皮肤刺激性、致敏性及离体透皮释药特性。方法：采用乳化法将甲硝唑、盐酸克林霉素、螺内酯和维生素B₆制备成复方甲硝唑克林霉素乳膏,并采用HPLC法测定乳膏中的4种主要成分的含量。评价乳膏对大鼠的皮肤毒性和刺激性,评价乳膏对豚鼠的皮肤致敏性。采用离体大鼠皮肤进行离体皮肤透皮释药试验,分别测定1,2,3,6,9、12,24,48 h各时间点甲硝唑、盐酸克林霉素、螺内酯、维生素B₆的单位面积透皮释药量Q及透皮吸收百分率Q%。结果：制得的复方甲硝唑克林霉素乳膏呈乳白色,均匀细腻,无颗粒感,易于涂布。采用梯度洗脱法能同时测定乳膏中4种主要成分的含量。离体透皮释药试验结果表明,给药12 h后甲硝唑、盐酸克林霉素、螺内酯、维生素B₆的Q、Q%均达到稳态值。给药6,12,24 h后,甲硝唑、盐酸克林霉素、螺内酯、维生素B₆均能不同程度地滞留在离体皮肤内。皮肤毒性试验结果可见,在7 d内均未出现死亡大鼠,未观察到急性毒性反应。皮肤刺激性试验结果可见,复方甲硝唑克林霉素乳膏的评分均值0.17,小于0.5,对大鼠皮肤无刺激性。皮肤致敏试验结果显示,复方甲硝唑克林霉素乳膏被评定为Ⅰ级致敏度,实际使用中对豚鼠并无致敏危险。结论：复方甲硝唑克林霉素乳膏的制备工艺简单可行,无皮肤毒性、刺激性和致敏性,且具有良好的透皮释药特性。     

Comparison of the response of psoriasis, over a 6-month period, to clobetasol propionate and fluocinolone acetonide ointments.

Twenty-nine patients with bilateral psoriasis were treated with clobetasol propionate ointment on one side of the body and fluocinolone acetonide ointment on the other in a double-blind clinical trial lasting 6 months. With one exception, after the first month of treatment, all patients responded better on the clobetasol propionate treated side. There was a tendency for any relapses to be less rapid and less severe in clobetasol propionate treated lesions. No adverse effects from either steroid were observed.     

Microemulsion-based delivery of triamcinolone acetonide to posterior segment of eye using chitosan and butter oil as permeation enhancer: an in vitro and in vivo investigation

The aim of the study was to formulate a microemulsion (ME) using chitosan (CH) and the butter oil (BO) as a permeation enhancer for targeting drug to the posterior segment of the eye, via topical route. Triamcinolone acetonide (TA) was selected as the model drug since it undergoes extensive first-pass metabolism, leading to poor oral bioavailability of 23%. For optimisation of BO concentration, different ratios of TA:BO were prepared by simple physical mixing in the ratio of 1:9 to 9:1 and diffusion study was performed. MEs containing TA, TA:BO and TA CH ME were formulated by water titration method. Globule sizes of TA ME, TA:BO ME and TA CH ME were found to be 66.06?±?0.32?nm, 78.52?±?1.50?nm and 97.30?±?2.50?nm, respectively. In ex vivo diffusion studies using goats eye, TA:BO ME (31.33?±?0.46 and 33.98?±?0.23) and TA CH ME (24.10?±?0.41 and 27.00?±?0.18) showed higher percentage of drug diffusion in comparison to TA ME (13.29?±?0.41and 15.56?±?0.34) and TA solution (8.20?±?1.04 and 10.39?±?0.22) in presence and in absence of vitreous humour. Fluorescence intensity of coumarin-6 (as a marker) loaded ME with BO and CH was found to be higher, confirming their role in altering membrane permeability and facilitating coumarin-6 diffusion to the posterior chamber. Overall, it was concluded that BO enhances the bioavailability of TA across the retina, thereby proving its potential as permeation enhancer in facilitating drug delivery to the posterior segment of the eye.     

In vitro and in vivo evaluation of a bondable compact for the prolonged delivery of triamcinolone acetonide to the oral cavity in patients with lichen planus

Compacts weighing 40 mg and containing triamcinolone acetonide 70-90% and polyhydroxybutyric acid (PHB) 30-10% or poly (DL-lactic acid) 20% with a diameter of 5 mm were bonded onto the side-wall of molar teeth. In vitro dissolution studies showed the compacts to release 12% of drug in 30 days with an initial burst effect. Drug loading or polymer matrix type had little effect. In vivo studies in dogs showed that compacts containing 80% drug in PHB produced salivary levels of triamcinolone acetonide for 30 days. When evaluated in five patients with lichen planus resistant to conventional therapy, these compacts produce a slight clinical improvement in three subjects. Differential scanning calorimetry studies confirmed that the drug and polymer were present as a physical mix in these compacts.     

Comparison of in vitro and in vivo release characteristics of acetaminophen from gradient matrix systems

An effort was made to correlate the in vivo and in vitro release data of acetaminophen from two formulations of a recently developed controlled-release system, the Gradient Matrix System (GMS-1 and GMS-2). The in vivo release curves, obtained by deconvolution of the plasma concentration time plots, showed a small inter-subject variability. GMS-1 with fastest in vitro release also showed fastest in vivo release. A good relationship was only found after time-scaling of the release data.     

Matrix metalloproteinase-9 expression and release from skin fibroblasts interacting with keratinocytes: Upregulation in response to sulphur mustard

Matrix metalloproteinases (MMPs), especially MMP-9 and MMP-2, degrade various proteins of the extracellular matrix, including collagen type IV the major component of basement membranes which also separate the epidermis from the dermis. Although previous work indicates the contribution of MMPs and their inhibitors (TIMPs) to the pathophysiology of skin lesions induced by the toxic chemical warefare agent sulphur mustard (SM), little is known about the underlying molecular and cellular mechanisms. In this study we demonstrate in a 3D-skin model that topical application of SM significantly upregulated basal MMP-9 mRNA expression and release from the cells as shown by qRT-PCR and zymography, whereas that of MMP-2, membrane-type 1 (MT1)-MMP, TIMP-1 and TIMP-2 remained almost unaffected by SM. Further studies in neonatal human dermal fibroblasts (NHDF) and HaCaT keratinocytes revealed that MMP-9 was not secreted from these cells, neither with or without exposure to SM. However, when NHDF and HaCaT were cocultivated, MMP-9 was expressed and released from the cell mixture, suggesting that interaction between both cell types is essential for MMP-9 production. Moreover, SM-treatment of NHDF/HaCaT cocultures further upregulated MMP-9 biosynthesis and secretion, which was consistent with our findings obtained in the 3D-skin model. Addition of conditioned medium derived from SM-exposed HaCaT cells to NHDF was able to stimulate MMP-9 secretion and also increased the migratory potential of NHDF as shown in a scratch-wound healing assay and a fluorescent cell invasion assay. In contrast, culture supernatants of SM-treated NHDF had not such an effect on HaCaT cells. Taken together, our findings provide first evidence that SM exposure of skin stimulates keratinocytes to release soluble factors which in turn induce enhanced MMP-9 secretion and invasiveness of fibroblasts in vitro. This provides a potential mechanism probably contributing to SM-evoked tissue injury in vivo.     

Comparison of the tissue affinity of glucocorticoids to human lung, nasal and skin tissue in vitro.

High affinity binding of topically applied glucocorticoids to their target tissues is the basis for prolonged action of the drug and reduces efflux into the systemic circulation that might account for adverse effects. Since little information on the accumulation and depletion of glucocorticoids to tissues of therapeutic interest is available the binding behavior of different glucocorticoids to human lung, nasal and skin tissue is now evaluated and drug concentrations in different tissues are compared. Furthermore, the role of tissue lipids and proteins in glucocorticoid binding is investigated. Therefore, sliced human lung, nasal and skin tissues are incubated with glucocorticoid containing buffers and time course of adsorption and desorption is monitored. Two model glucocorticoids, the highly lipophilic fluticasone propionate (CAS 80474-14-2) and the rather hydrophilic hydrocortisone (CAS 50-23-7) are compared respecting their binding to native and lipid-depleted tissues. While total adsorption rates to different tissues were highly comparable for each glucocorticoid the observed initial desorption was clearly different. Highest initial depletion was seen for lung tissue, lowest for skin tissue. After initial depletion a prolonged desorption of very low concentrations is observed for all tissues. Lipid depletion of tissues did neither change accumulation not depletion behavior except that about twice as high concentrations were bound and depleted, probably due to protein denaturation. It is concluded that glucocorticoids primarily bind to protein components of human lung, nasal and skin tissues. Connective tissue proteins are discussed to bind glucocorticoids with higher affinity than other protein components, thus preventing high initial release rates. While total amounts of adsorption to different tissues are equivalent and initial desorption of glucocorticoids from saturated tissues varies, highest total remaining concentrations should be observed in skin tissue followed by nasal and lung tissue. Although tissue lipids seem to play no role in total glucocorticoid binding they are suggested to influence the rate constant of uptake and depletion.     

Comparison of in vitro dissolution profiles by ANOVA-based, model-dependent and -independent methods

In this study, the aim was to apply different comparison methods to dissolution profiles of immediate release commercial film-coated tablets of naproxen sodium in order to (1) evaluate each method in terms of easy application and usefulness and (2) identify the advantages and disadvantages of each method. Dissolution testing was conducted using the USP monograph of naproxen sodium. The applied methods for the comparison of in vitro dissolution profiles are ANOVA-based methods, model-dependent methods, and model-independent methods including difference factor, f(1), and similarity factor, f(2). All the methods appear to be applicable and useful in comparing dissolution profiles. The results show that ANOVA-based methods and model-dependent methods are more discriminative than the f-factors. f-Factors seem to be easier to apply and interpret; only one value is obtained to describe the closeness of the two dissolution profiles. However, a last point for dissolution had to be determined, since the values of the f-factors depend on this point. The application and evaluation of model-dependent methods are more complicated; these methods present an acceptable model approach to the true relationship between percent dissolved and time variables, including statistical assumptions which could be checked. Dissolution profiles can be tested for differences in both level and shape by ANOVA-based methods and these methods provide detailed information about dissolution data which can be useful also in formulation development to match release to a reference product.     

Use of an in vitro human skin permeation assay to assess bioequivalence of two topical cream formulations containing butenafine hydrochloride (1%, w/w)

The primary objective of this work was to investigate, using an in vitro human skin permeation study, whether changes in the excipients of butenafine hydrochloride cream would have any effect on bioperformance of the formulation. Such in vitro data would be a surrogate for any requirement of a bioequivalence (BE) study to demonstrate formulation similarity. A LC-MS/MS method for quantitation of butenafine in various matrices was developed and validated. A pilot study was performed to validate the in vitro skin permeation methodology using three cream formulations containing butenafine hydrochloride at concentrations of 0.5, 1.0 and 1.5% (w/w). Finally, a definitive in vitro human skin permeation study was conducted, comparing the extent of butenafine hydrochloride permeation from the new formulation to that from the current formulation. The results of the study comparing the two formulations showed that there was no statistically significant difference in the extent of butenafine permeation into human skin. In conclusion, these in vitro data demonstrated that the formulation change is likely to have no significant impact on the bioperformance of 1% (w/w) butenafine hydrochloride cream.     

Formulation, characterization, and in vitro release of glyburide from proliposomal beads

The objective of our study was to formulate and evaluate proliposomes in the form of enteric-coated beads using glyburide as a model drug. The beads were enteric coated with Eudragit L-100 by a fluidized bed coating process using triethyl citrate as plasticizer. Content uniformity of glyburide was estimated using HPLC analysis of beads dissolved in methanol. These proliposomal beads formed liposomes on disintegration in phosphate buffered saline (pH 7.4), which was confirmed by transmission electron microscopy. The dissolution study of enteric-coated beads exhibited enhanced dissolution compared with pure drug and a marketed product. Liposomes can be successfully prepared for oral administration in the form of enteric-coated beads that may offer a stable system to produce liposomes for oral administration.     

Absorption and evaporation of N,N-diethyl-m-toluamide from human skin in vitro

The penetration of DEET through split-thickness cadaver skin was measured in non-occluded Franz cells placed either in a fume hood or on a laboratory workbench. DEET, dissolved in a small volume of ethanol and spiked with (14)C radiolabel was applied to skin at doses from 0.02 to 11000 microg/cm(2). DEET penetration was greater for cells placed on the workbench, and the percentage of radioactivity penetrated after 72 h increased gradually with dose, for doses up to 680 microg/cm(2). At higher doses, it declined. Percent penetration ranged from 11.5 +/- 3.2% for a dose of 0.021 microg/cm(2) in the fume hood to 71.9 +/- 5.5% for a dose of 260 microg/cm(2) on the workbench. Results were interpreted in terms of a diffusion/evaporation model having three parameters-a solubility value for the chemical in the upper stratum corneum, M(sat); a mass transfer coefficient for evaporation, k(evap); and a characteristic time for diffusion, h(2)/D. The parameters obtained from fitting the model to the data (normalized to the fume hood environment) were M(sat) = 18 microg/cm(2) and k(evap) = 2.6 x 10(-5) cm/h. The value of h(2)/D decreased from 16 h at a DEET dose of 25 microg/cm(2) to 10 h at 1480 microg/cm(2), consistent with an increase in skin permeability of about 1.5-fold over this dose range. This effect was confirmed by means of an additional study in which skin samples pretreated with increasing amounts of unlabeled DEET were washed and redosed with (14)C-benzyl alcohol. A small (1.7-fold), but significant, increase in benzyl alcohol penetration with increasing amount of DEET was obtained. Thus, DEET enhanced its own skin permeation rate as well as that of another compound, but the effect was modest and not likely to be a major concern for compounds coadministered with DEET.     

The release of prostaglandin D2 from human skin in vivo and in vitro during immediate allergic reactions.

1. The release of prostaglandin D2 (PGD2) during immediate allergic reactions in human skin was investigated in vivo and in vitro. 2. Skin exudates were collected from abraded sites on the thigh of atopic subjects sensitive to D. pteronyssinus antigen and from non-atopic control subjects. Challenge with antigen caused the release of PGD2 and histamine, but not PGE2, from the skin of the atopic subjects. The molar ratio of histamine to PGD2 was about 140:1. Control subjects were unresponsive. 3. PGD2 was released from passively sensitized human skin challenged with antigen in vitro. The time course was similar in vitro and in vivo. The ratio of histamine to PGD2 in vitro was 78:1. 4. The identities of the prostaglandins were confirmed by high performance liquid chromatography and radioimmunoassay to PGD2 and PGE2. 5. PGD2 is the major arachidonic acid cyclo-oxygenase product synthesized by human mast cells. It is pro-inflammatory in human skin but its functions as a mediator in immediate hypersensitivity reactions in human skin are not clear. The results of this study suggest that, relative to histamine, PGD2 contributes little to the oedema and erythema of immediate reactions in human skin.