In vitro transcutaneous delivery of ketoprofen and essential polyunsaturated fatty acids from a fish oil vehicle incorporating 1,8-cineole

Transcutaneous administration of nonsteroidal anti-inflammatory drugs and essential fatty acids from fish oil, principally eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may simultaneously lead to increased cyclooxygenase inhibition and the production of less potent inflammatory mediators within joints. The objective of our study was to determine the permeation of ketoprofen, EPA, and DHA (from fish oil) across pig ear skin in vitro in the presence of the enhancer 1,8-cineole. Formulations containing 2.5% ketoprofen in fish oil with varying concentrations of 1,8-cineole were prepared and applied to full-thickness pig ear skin mounted in all glass Franz-type diffusion cells. Simultaneous permeation of ketoprofen and EPA and DHA from these formulations was determined by reverse phase HPLC over a 48-hr period (n = 6). We found that fish oil alone enhanced the permeation of ketoprofen across pig ear by a factor of 1.72 relative to a water vehicle. There was a dose-dependent increase in the rate of permeation of ketoprofen relative to the concentration of 1,8-cineole. The highest Q24 and Q48 was obtained with a 20% 1,8-cineole formulation with values of 355.78 +/- 50.73 microg cm(-2) and 963.29 +/- 136.69 microg cm(-2), respectively. Surprisingly, no clear effect upon the permeation of EPA and DHA by 1,8-cineole was observed, with the highest Q24 and Q48 values seen in a formulation containing no 1,8-cineole. This may have been due to differential solvation effects prior to or during the permeation process or modulation of the skin during the permeation process.     

In-vitro transcutaneous delivery of ketoprofen and polyunsaturated fatty acids from a pluronic lecithin organogel vehicle containing fish oil

This work explored the use of pluronic lecithin organogel (PLO) as a base for the delivery of bioactive polyunsaturated fatty acids from fish oil, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and ketoprofen. PLO was adapted to contain fish oil, ketoprofen, or both, and 1,8-cineole as penetration enhancer, and used to determine the in-vitro permeation from infinite and finite dosing protocols across full thickness porcine skin. Oruvail gel (2.5% ketoprofen) was included for comparison. No EPA or DHA was found to permeate skin when applied as an infinite dose. From multiple finite doses, small amount (max. 0.22%) of fish oil were found to permeate the skin. This indicates retention of fish oil within the gel matrix and that the viable domain of full thickness skin was a significant barrier. Greater amounts of EPA and DHA were delivered in the presence of ketoprofen indicating co-transport resulting from selective complexation, although no enhancement was observed using 1,8-cineole. Unlike EPA and DHA, substantial amounts of ketoprofen permeated when applied as infinite doses. Oruvail, a Carbopol 940-based hydrogel containing 2.5% ketoprofen and ethanol, delivered the greatest amount, although similar to the PLO gel containing 5% ketoprofen. The addition of propylene glycol enhanced permeation, although the presence of fish oil in the PLO gel inhibited ketoprofen permeation. When applied as multiple finite doses a maximum of 76 microm cm(-2) (1.12%) was delivered, which was reduced by the presence of 1,8-cineole. Greater permeation was again observed with Oruvail by a factor of two and with half the ketoprofen dose. To conclude, a PLO-based gel is capable of delivering EPA and DHA via a repeat finite dosing regimen, although there is evidence for the retention of these very lipophilic molecules within the gel matrix. Although to a lesser extent than EPA and DHA, ketoprofen was also substantially retained, as exemplified by the superior delivery rates from Oruvail. Finally, this work has highlighted the importance of using an appropriate topical dosing method to match the intended use of a product.     

The in vitro delivery of NSAIDs across skin was in proportion to the delivery of essential fatty acids in the vehicle--evidence that solutes permeate skin associated with their solvation cages?

As part of our investigations into novel dual action topical anti-arthritis systems, the permeation of ibuprofen or ketoprofen plus eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were determined from a fish oil vehicle across pig ear skin in vitro. The steady state fluxes of ibuprofen and ketoprofen were 9.17+/-1.98 microgram cm(-2)h(-1) and 6.12+/-2.39 microgram cm(-2)h(-1), respectively. At 24h, 5.7 microgram cm(-2) EPA and 3.1 microgram cm(-2) DHA permeated when the solute was ibuprofen; 1.4 microgram cm(-2) EPA and 1.0 microgram cm(-2) DHA when ketoprofen was the solute. At 12h, the ketoprofen/ibuprofen ratio of the moles permeated was 0.27, the ratio of EPA permeated simultaneously with ketoprofen and ibuprofen was 0.22 and the ratio of DHA permeated simultaneously with ketoprofen and ibuprofen was 0.24. We believe this is the first time that simultaneous permeation across skin of a solute and its vehicle has been determined purposefully. The data successfully demonstrated that simultaneous permeation of NSAIDs and essential fatty acids, EPA and DHA from a formulation containing fish oil is feasible. In addition, for both NSAIDs, the relative rates of permeation of EPA and DHA, were in proportion to their levels in the fish oil and the permeation rate of either fatty acid was higher when the permeation rate of the solute was greater. This suggested that the greater the rate of permeation of the NSAID, the greater the rate of permeation of the vehicle, and that a solute permeates skin complete with its vehicular solvation cage. This apparent relationship between solute and vehicle fluxes may be of more widespread significance to skin permeation experimentation.     

In-vitro transcutaneous delivery of tamoxifen and gamma-linolenic acid from borage oil containing ethanol and 1,8-cineole

The objective of this study was to examine the effects of ethanol and 1,8-cineole on the transcutaneous delivery of tamoxifen and gamma-linolenic acid (GLA) as a two-pronged anti-breast cancer therapy. Formulations containing tamoxifen and varying concentrations of borage oil (approximately 25% GLA), 1,8-cineole and ethanol were prepared and the simultaneous permeation of tamoxifen and GLA determined across full-thickness pig skin using Franz-type diffusion cells over 48 h. Analysis of tamoxifen and GLA (as methyl ester) were by reverse-phase HPLC. The highest flux of tamoxifen of 488.2 +/- 191 x 10(-3) microg cm(-2) h(-1) was observed with a formulation containing 20% 1,8-cineole and 20% ethanol. The same formulation also provided the greatest flux of GLA, 830.6 x 10(-3) microg cm(-2 )h(-1). The findings from this work demonstrate the ability of 1,8-cineole and ethanol to enhance the in-vitro permeation of tamoxifen and GLA across the skin and support the plausibility of simultaneously delivering tamoxifen and GLA transcutaneously as a two-pronged anti-breast cancer system.     

Probing the skin permeation of fish oil/EPA and ketoprofen 1. NMR spectroscopy and molecular modelling

The complexation of EPA with ketoprofen was probed in order to rationalise co-operative skin permeation enhancement behaviour observed previously. The modulation of aromatic protons of ketoprofen was determined using (1)H NMR spectra from different formulations containing varying concentrations of fish oil and a control saturated triglyceride. Molecular modelling of possible complexes of ketoprofen with constituents of fish oil was performed. NMR data revealed a dose-dependent change in chemical shift in the aromatic protons of ketoprofen on addition of fish oil and/or EPA. Similar patterns were observed in both cases, although the free fatty acid induced changes in more protons. Molecular modelling results indicate quite large binding energies of all complexes considered, varying between ca. 90 and 160 kJ mol(-1). The geometries of these complexes shows strong O-H...O hydrogen bonds in all cases, and in the case of the complex of ketoprofen with free EPA there is also some evidence of C-H... pi and/or pi-pi interactions, giving rise to regiospecifically solvated complexes. If strongly bound ketoprofen:EPA complexes can form, then the permeation enhancement of EPA by ketoprofen could be attributed to such a complex. Once the complex is formed, the triglyceride/free fatty acid could aid permeation of associated ketoprofen into the lipophilic stratum corneum via the pull effect. Once permeated, the more hydrophilic ketoprofen could aid the permeation of the triglyceride/free fatty acid through the epidermis, again via the pull effect. This could explain the synergistic permeation enhancement seen with these compounds.     

Investigation of enhancer structure activity relationships in congeners of 2-(1-nonyl)-1,3-dioxolane

Twelve analogues of 2-(1-nonyl)-1,3-dioxolane were examined for enhancer activity using occluded hairless mouse skin in vitro with hydrocortisone as the model drug. Controls consisted of no enhancer or vehicle pretreatment (I) or propylene glycol pretreatment 1 h prior to drug application (II). Enhancers were applied at 0.4 M in propylene glycol (PG) 1 h prior to skin application of a saturated suspension of hydrocortisone in the same vehicle. The highest 24-h receptor concentration (Q₂₄) of steroid was observed using 2-(1-nonyl)-1,3-dioxolane: 131.472 ± 20.659 μM compared to Control I of 16.462 ± 4.859 Rm. Control II Q₂₄ values were 34.015 ± 9.959 μm. The highest skin steroid content was produced by 2-(1-nonyl)-2-methyl-1,3-dioxolane: 431.4 ± 212.2 μg g^-1 and 2-(1-nonyl)-2,4-dimethyl-1,3-dioxolane: 385.7 ± 138.7 μg g^-1. Skin steroid content of Control I was 490.2 ± 243.2 μg g^-1 and of II was 112.7 ± 31.3 μg g^-1. Control I and II results indicated that PG was exhibiting enhancer activity. All 12 dioxolanes showed poor skin steroid retention (compared with Control I), suggesting that these compounds could be useful for enhancing systemic rather than local drug delivery.     

In vitro dermal absorption of pesticides: IV. In vivo and in vitro comparison with the organophosphorus insecticide diazinon in rat, guinea pig, pig, human and tissue-cultured skin

In vitro skin absorption tests are currently being developed as an alternative to in vivo animal tests for predicting the degree of occupational exposure to pesticides. In the study reported here, in vitro percutaneous absorption tests were conducted with the ¹⁴C-ring-labelled pesticide, diazinon, dissolved in acetone and applied to the dermatomed skin (0.5 mm) of a number of species at a dose rate of 9.5–16.7 μg/cm². Skin permeation was determined for 48 hr after exposure using an in vitro flow-through system. Skin permeation was calculated from the sum of the percentage recovery of ¹⁴C activity in the receiver solution and the percentage recovery obtained in methanol washes of the skin at 48 hr and in skin digests. Listed in decreasing order, the total percentage in vitro dermal absorptions (mean ± SD) obtained by 48 hr after exposure for the five skin types were: 47 ± 3.4% (rat), 36 ± 0.9% (tissue cultured Testskin), 33 ± 2.8% (hairless guinea pig), 20 ± 3.1% (human) and 15 ± 13.1% (pig). The percentage recoveries in soapy water skin washes at 24 hr, in methanol washes and skin digests at 48 hr and of ¹⁴C-labelled volatiles collected in air traps at 48 hr after exposure are reported. Comparative in vivo studies demonstrated 37 ± 0.8 and 24 ± 5.7% recovery of ¹⁴C in the urine of rats (dose rate, 6 μg/cm²) and hairless guinea pigs (dose rate, 5 μg/cm²), respectively, by 14 days after exposure. Total faecal recovery 14 days after exposure was 18 ± 0.4 and 4 ± 0.9% for rats and guinea pigs, respectively. Analysis of tissue taken at autopsy 14 days after exposure demonstrated a total tissue recovery of 0.6 ± 0.1% [¹⁴C]diazinon in rats and 1 ± 0.2% in hairless guinea pigs. The total recovery in skin removed from the dose site at 14 days after exposure was 0.2 ± 0.02% and 0.1 ± 0.05% in rats and hairless guinea pigs, respectively. Recovery of radioactivity from soapy water skin washes conducted at 24 hr after exposure was 21 ± 3.8% for rats and 2 ± 0.1% for hairless guinea pigs. Recovery in skin patches was 23 ± 5.4% and 73 ± 2.9% in rats and hairless guinea pigs, respectively. The in vitro data for dermal absorption of [¹⁴C]diazinon for rats (47 ± 3.4%) and hairless guinea pigs (33 ± 2.8%) were in good agreement with the data observed for rats (56 ± 1.03%) and hairless guinea pigs (28 ± 6.0%) in vivo. This study supported the use of in vitro skin absorption tests as an alternative to in vivo animal testing.     

Effect of formulation variables on the percutaneous permeation of ketoprofen from gel formulations

The objectives of our study were to evaluate the effect of four terpene enhancers, enhancer lipophilicity, and ethanol concentration using hydroxypropyl cellulose (HPC) and two Pluronic F-127 (PF-127) gel formulations on the percutaneous permeation of ketoprofen. All experiments were conducted using hairless mouse skin in vitro. Data recorded over 24 hr was compared with that for control gels (containing no terpene) using Franz diffusion cells. In the three gel formulations, the highest increase in the ketoprofen permeation was observed using limonene followed by nerolidol, fenchone, and thymol. Relationships were established between terpene lipophilicity, enhancement ratios for ketoprofen flux (ER_flux), and the cumulative amount of ketoprofen after 24 hr (Q₂₄     

Film drying and complexation effects in the simultaneous skin permeation of ketoprofen and propylene glycol from simple gel formulations

This work investigated the simultaneous permeation of ketoprofen and propylene glycol (PG) across pig ear skin from simple gel formulations administered under simulated in-use conditions. The aims were to quantify rates of permeation of both solvent and active, probe the effects of formulation drying and gain insight into drag/complexation interactions. Simple 3-component gels were formulated using a fixed amount of ketoprofen and hydroxypropyl cellulose thickener with decreasing content of solvent propylene glycol. Multiple finite (5 mg x 15 mg) doses were massaged over 24h into full thickness pig ear skin in vertical Franz-type diffusion cells. The permeation of ketoprofen was inversely proportional to the content of PG, whereas the permeation of PG was directly proportional, although the amount of PG permeated was always greater than ketoprofen, even from the driest gel practically achievable. In this state, the molar ratio of PG/ketoprofen was approximately 12, suggesting that this number of PG molecules constitutes the solvation cage of ketoprofen. Dragging/pulling effect extends throughout the skin and into the receptor compartment and probably the system, in an in vivo situation. Although PG may represent a worse case scenario given its well-documented skin permeation enhancement properties, it is probable that other solvents exert a similar effect on solutes across skin. A drying film will behave in different ways depending on the nature of both the thickener and solvent, where the outcomes are not readily predictable. It is important to account for the fate of all species administered from a topical formulation.     

In vitro dermal absorption of pesticides: VI. In vivo and in vitro comparison of the organochlorine insecticide DDT in rat, guinea pig, pig, human and tissue-cultured skin

In vitro dermal absorption tests were conducted with the ¹⁴C-ring-labelled pesticide, 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) dissolved in acetone and applied to dermatomed skin (0.5 mm) of a number of species at dose rates of 16–27 μg/cm². Skin absorption was determined for 48 hr after exposure using in vitro flow-through cells. Skin absorption was calculated from the sum of the percentage recovery of ¹⁴C activity in the receiver solution added to the percentage recovery for the methanol washes of the skin at 48 hr and the skin digest samples. Two receiver solutions, Ringer's saline (used with Moody aluminium cells), and Hanks' HEPES buffered saline with 4% serum albumin (used with Bronaugh flow-through cells) were used. Listed in decreasing order, the total percentage in vitro dermal absorptions obtained by 48 hr after exposure for the five skin types were: 42 ± 2.6% [hairless guinea pig; Hanks' receiver (HR)], 34 ± 10.5% (rat; HR), 28 ± 13.2% [Testskin; Ringer's receiver (RR)], 28 ± 2.9% (human; HR), 22 ± 3.3% (Testskin; HR), 18 ± 6.2% (pig; RR) and 14 ± 2.1% (pig; HR). The percentage ¹⁴C activity recovered in soapy water rinses of the skin specimens at 24 hr, and for methanol skin washes and skin digests at 48 hr, and of ¹⁴C-labelled volatiles collected in air traps are reported. Data obtained with pig and Testskin for DDT using the Moody flow-through permeation cell was compared with that obtained using the Bronaugh cell. Significantly greater (P < 0.05) percentage recovery was obtained for the soap washes at 24 hr of the skin following the Bronaugh procedure than was obtained with the Moody method. Comparative in vivo studies demonstrated urinary recovery was 2 ± 0.5 and 15 ± 1.7% for rats (dose rate; 6 μg/cm²) and guinea pigs (dose rate: 9 μg/cm²), respectively. Total faecal recovery was 20 ± 1.9 and 44 ± 2.75% for rats and guinea pigs, respectively. Analysis of tissue taken at autopsy 14 days after dosing demonstrated total tissue recovery of 51 ± 5.6% in rats but of only 3 ± 0.7% in guinea pigs. Including the ¹⁴C activity extracted from the skin removed from the dose site at 14 days after exposure, the total recovery of dermally absorbed residues was 73 ± 5.9 and 62 ± 4.1% for rats and guinea pigs, respectively. Recovery of ¹⁴C from soapy water skin washes conducted at 24 hr after exposure was 3 ± 1.4 and 14 ± 1.8% for rats and guinea pigs, respectively, and this was significantly less than that obtained by both the Bronaugh and Moody in vitro procedures. Skin patch recovery was 24% for both rats and guinea pigs. In summary, the in vitro data underestimed the degree of dermal absorption observed in vivo for both rats and guinea pigs, and this was thought to be due to an overly vigorous removal of the pesticide skin deposit by the soap washing procedures used in vitro in comparison with the in vivo washing procedure.     

Percutaneous penetration of octyl salicylate from representative sunscreen formulations through human skin in vitro

The human skin penetration of [¹⁴C]octyl salicylate from two representative sunscreen vehicles was determined in vitro. ³H-sucrose was incorporated into all formulations and provided a marker for membrane integrity. When applied as a finite dose in an oil-in-water emulsion vehicle containing 5% (w/w) octyl salicylate, the average total absorption of ¹⁴C over 48 hr was 0.65 ± 0.16% of the applied dose (representing a total amount permeated of 1.58 ± 0.36 μg/cm²). When applied as an infinite dose in the oil-in-water emulsion vehicle the average total absorption of ¹⁴C over 48 hr was 0.47 ± 0.22% of the applied dose (representing a total amount permeated of 27.54 ± 13.91 μg/cm²). When applied as a finite dose in a representative hydroalcoholic formulation containing 5% (w/w) octyl salicylate, the average total absorption of ¹⁴C over 48 hr was 0.59 ± 0.09% of the applied dose (representing a total amount permeated of 1.58 ± 0.25 μg/cm²). When applied as an infinite dose in the hydroalcoholic formulation the average total absorption of ¹⁴C over 48 hr was 0.23 ± 0.05% of the applied dose (representing a total amount permeated of 11.28 ± 2.55 μg/cm²). The penetration of [¹⁴C]salicylic acid [applied at a concentration of 2.7% (w/w), in the oil-in-water emulsion] was also determined. When applied as a finite dose the average total absorption of ¹⁴C over 48 hr was 1.14 ± 0.23% of the applied dose (representing a total amount permeated of 1.65 ± 0.39 μg/cm²). These results suggest that the in vitro human skin permeation of octyl salicylate is relatively low. The amounts of octyl salicylate and salicylic acid permeated when applied in similar vehicles were remarkably similar over 48 hr (1.58 μg/cm² and 1.65 μg/cm², respectively). This suggests the possibility that the ¹⁴C label appearing in the receptor fluid may, in both cases, represent salicylic acid. If this is the case, then it is possible that the amount of octyl salicylate permeating through the skin is much less than that suggested by the data obtained here. This supposition is, however, entirely speculative and has yet to be confirmed experimentally.     

Skin penetration enhancement of mefenamic acid by ethanol and 1,8-cineole can be explained by the 'pull' effect

The simultaneous skin permeation of drug and penetration enhancer have been studied in vitro. Simple formulations of mefenamic acid in PEG400 incorporating various proportions of ethanol or 1,8-cineole were prepared and applied to porcine ear skin in diffusion cells under infinite conditions. Receptor phases were assayed for mefenamic acid by HPLC and ethanol or 1,8-cineole by GC. Concentration-dependent permeation profiles were obtained for both ethanol or 1,8-cineole, in addition to concentration-dependent enhancement of mefenamic acid. When the steady state flux of mefenamic acid was plotted against ethanol or 1,8-cineole, linear relationships were observed with r2 values of 0.988 and 0.999, respectively. The close connection between rates of excipient and solute permeation is generally referred to as the 'pull' (or 'drag') effect, where in this case permeation of the enhancer facilitated permeation of the solute. This appears to be sufficient to account for the enhancing activity of ethanol and 1,8-cineole, notwithstanding initial modulations that may occur within the stratum corneum.     

Solvent content and macroviscosity effects on the in vitro transcutaneous delivery and skin distribution of ketoprofen from simple gel formulations

The effects of decreasing solvent content and macroviscosity of simple topical gel formulations on the transcutaneous delivery and distribution of ketoprofen through skin were studied. Simple topical gels, based on ketoprofen, PEG 400 and either Cabosil M-5 or hydroxypropylcellulose were formulated and applied to freshly excised pig ear skin in vitro. Receptor phase samples were taken to determine permeation and depth profiles of ketoprofen were constructed, following tape stripping and membrane separation. Reduction of solvent from the Cabosil-thickened gels resulted in a rank order reduction in the permeation and distribution of ketoprofen. Reduced amounts of ketoprofen were distributed through the skin, particularly the dermis, with decreasing solvent. Two gels sharing the same macroviscosity exhibited significantly different skin permeation and distribution characteristics. The rank order reduction in both permeation and distribution of ketoprofen was attributed to the physiochemical properties of the formulation and how they may change after application, in particular the increased adsorptivity of ketoprofen to the Cabosil relative to the amount of solvent present in the system. This effect appeared to be predominant over any interactions occurring between the formulation and the skin. The data provided further evidence that adsorption to the thickener, rather than changes in viscosity, were primarily responsible for reduced permeation and distribution in the system examined.     

In vitro percutaneous absorption studies and in vivo evaluation of anti-inflammatory activity of essential fatty acids (EFA) from fish oil extracts

The aim of the present study was to evaluate the in vitro percutaneous absorption and the in vivo anti-inflammatory activity of EPA and DHA fatty acids from three oily extracts, obtained by acetonic extractions from the entrails of different varieties of Mediterranean fishes such as mackerel (Scomber scombrus), sardine (Sardina pilchardus) and horse mackerel (Trachurus mediterraneus). In the first part of our research, we focused our attention on the characterization of the oily extracts to determine their omega-3 polyunsaturated fatty acid content, then, we evaluated the in vitro percutaneous absorption through excised human skin (stratum corneum/epidermis membranes; SCE) of EPA and DHA contained in the extracts. In the second part, the fish oil which guaranteed the best in vitro permeation profile of these omega-3 fatty acids was studied in order to evaluate its inhibiting ability towards the in vivo UVB-induced skin erythema. From the results obtained, all the fish oils tested in this study presented significant amounts of omega-3 fatty acids EPA and DHA, and particularly sardine oil extract showed higher concentrations of these substances compared to the other two fish oils. The in vitro experiments revealed interesting fluxes of these compounds from sardine extract through the stratum corneum/epidermis membranes and an appreciable anti-inflammatory activity against UVB-induced erythema in human volunteers was also observed.     

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).     

黄连膏体外透皮吸收及抗炎活性研究

目的：采用改良的Franz透皮扩散池考察黄连膏中主要活性成分的体外透皮吸收情况,同时对黄连膏的抗炎活性进行初步研究。方法：选用改良Franz透皮扩散池,接收液为30%乙醇生理盐水,以小鼠背部皮肤为透皮材料,采用紫外分光光度法及高效液相色谱法测定透皮接收液中盐酸小檗碱、芝麻酚、芝麻素及总生物碱的含量,计算透皮吸收动力学参数,考察黄连膏中抗炎活性成分的累计透过量及吸收规律;取30只SPF级小鼠,随机分为5组,即模型组、醋酸地塞米松乳膏组（100 mg·kg^-1）、黄连膏高剂量组0.075 g·g^-1（生药/膏）、黄连膏中剂量组0.15 g ·g^-1（生药/膏）、黄连膏低剂量组0.3g ·g^-1（生药/膏）,每组6只。阳性对照组为醋酸地塞米松乳膏组,进行2,4-二硝基氯苯（DNCB）致小鼠耳肿胀实验,观察黄连膏对炎症的抑制作用。结果：黄连膏中芝麻酚、盐酸小檗碱、芝麻素及总生物碱在24 h内的累积透过量分别为2.82,4.10,0.78,16.54 μg·cm^-2;稳态透皮速率（J_s）分别为0.125 2,0.181 4,0.034 2,0.745 7 μg·cm^-2·h^-1;与阳性对照组比较,黄连膏高剂量组显著抑制DNCB所致小鼠耳肿胀。结论：黄连膏具有良好的体外透皮性能及抗炎活性,24 h内单位面积累积透过量随药物中主要有效成分含量升高而增加,经皮渗透行为符合零级动力学方程。     

在体猪耳静脉灌流经皮吸收模型的建立与应用

目的建立在体猪耳静脉灌流经皮吸收模型，为经皮吸收制剂研究提供新方法。方法建立在体猪耳静脉灌流经皮吸收模型。以葡萄糖利用试验及乳酸脱氢酶活性检测评价模型的生物学活性，以酮洛芬异丙酯和水杨酸甲酯为模型药物考察系统的应用。结果葡萄糖利用及乳酸脱氢酶活性检测表明系统7 h内保持良好生物学活性。酮洛芬异丙酯经皮渗透过程中被完全代谢为酮洛芬，稳态时酮洛芬累积形成量Q与时间t回归的方程为Q=-0.024+0.120t，形成速率为0.120　μg·cm^-2·h^-1。水杨酸甲酯经皮渗透过程中部分被代谢为水杨酸，稳态时水杨酸甲酯累积渗透量Q与时间t回归的方程为Q=-3.809+6.129　t，渗透速率为6.129　μg·cm^-2·h^-1；水杨酸累积形成量Q与时间t回归的方程为Q=-1.785+0.879　t，形成速率为0.879　μg·cm^-2·h^-1。结论该模型操作简便、价格经济，不仅可以考察药物的经皮吸收，而且能够用于研究药物的皮肤代谢。     

In vitro dermal absorption of pesticides: V. In vivo and in vitro comparison of the herbicide 2,4-dichlorophenoxyacetic acid in rat, guinea pig, pig, human and tissue-cultured skin

In vitro dermal absorption tests were conducted with the ¹⁴C-ring-labelled herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), dissolved in acetone and applied to dermatomed skin (0.5 mm) of a number of species at dose rates of 7–8 μg/cm². Skin absorption was determined for 48 hr after exposure using an in vitro flow-through system. Skin absorption was calculated from the sum of the percentage recovery of ¹⁴C activity in the receiver solution and the percentage recovery in the methanol washes of the skin at 48 hr and the skin digest samples. Two receiver solutions, Ringer's saline, and Hanks' HEPES buffered saline with 4% serum albumin were used. Listed in decreasing order, the total percentage in vitro dermal absorptions obtained by 48 hr after exposure for the five skin types were: 47 ± 4.3% [tissue cultured Testskin; Hanks' receiver (HR)], 40 ± 4.5% (rat; HR), 19 ± 1.8% (human; HR), 14 ± 2.3% (hairless guinea pig; HR), 14 ± 8.8% (pig; Ringer's receiver). The percentage recovery of the radiolabel in soapy water skin washes at 24 hr, methanol washes and skin digests at 48 hr, and of ¹⁴C-labelled volatiles collected in air traps at 48 hr after exposure are reported. Comparative in vivo studies were conducted for 14 days after exposure and demonstrated 32 ± 3.9 and 28 ± 7.8% recovery of ¹⁴C in the urine of rats (dose rate, 3 μg/cm²) and guinea pigs (dose rate, 4 μg/cm²), respectively. Total faecal recovery was 2 ± 0.3 and 9 ± 3.5% for rats and guinea pigs, respectively. Analysis of tissue taken at autopsy 14 day after dosing demonstrated a total tissue recovery of ¹⁴C activity of 1 ± 0.1 and 2 ± 0.5% in rats and guinea pigs, respectively. Including the ¹⁴C activity extracted from the skin removed from the dose site at 14 days after exposure, the total recovery of dermally absorbed residues was 49 ± 10.4 and 40 ± 9.9% in rats and guinea pigs, respectively. Recovery of ¹⁴C activity from soapy water skin washes conducted at 24 hr after exposure was 28 ± 8.1 and 43 ± 9.0% for rats and guinea pigs, respectively. Recovery in skin patches was 18% (guinea pigs) and 26% (rats). In summary, the in vitro/in vivo concordance for the rat dermal absorption data was good but the in vitro data for hairless guinea pigs underestimated the in vivo absorption, and therefore for 2,4-D, rat skin may provide a better model of percutaneous absorption.     

Probing the skin permeation of eicosapentaenoic acid and ketoprofen 2. Comparative depth profiling and metabolism of eicosapentaenoic acid.

Unexpected enhancement of the topical delivery of eicosapentaenoic acid (EPA) across porcine skin was observed previously when fish oil was co-formulated with ketoprofen. In the current work depth profile analysis was used to probe the epidermal conversion of EPA to its 15-hydroxy metabolite in the presence and absence of ketoprofen. Freshly excised full-thickness porcine skin in Franz diffusion cells was dosed (both infinite and finite) with simple formulations based on fish oil as source of EPA. After 24h the skin was subjected to tape stripping and depth profiles were constructed. Typical depth profiles were obtained, with an inverse relationship between depth and permeant concentration. 15-HEPE was generated in the skin when Hepes-modified Hanks' balanced salt solution was used, but none was detected when a cetrimide receptor phase was used, highlighting the importance of maintaining skin viability in such exercises. Ketoprofen had a direct influence on the metabolism of EPA and resulting in conversion to its 15-LOX metabolite 15-HEPE. However, this link appears to be only part of the solution of EPA enhancement however, as even in non-viable skin ketoprofen had an enhancing affect.     

SB-616234-A (1-[6-(cis-3,5-dimethylpiperazin-1-yl)-2,3-dihydro-5-methoxyindol-1-yl]-1-[2'methyl-4'-(5-methyl-1,2,3-oxadiazol-3-yl)biphenyl-4-yl]methanone hydrochloride): a novel, potent and selective 5-HT1B receptor antagonist

SB-616234-A possesses high affinity for human 5-HT_1B receptors stably expressed in Chinese hamster ovary (CHO) cells (pK_i 8.3 ± 0.2), and is over 100-fold selective for a range of molecular targets except h5-HT_1D receptors (pK_i 6.6 ± 0.1). Similarly, affinity (pK_i) for rat and guinea pig striatal 5-HT_1B receptors is 9.2 ± 0.1. In [³⁵S]-GTPγS binding studies in the human recombinant cell line, SB-616234-A acted as a high affinity antagonist with a pA₂ value of 8.6 ± 0.2 whilst providing no evidence of agonist activity in this system. In [³⁵S]-GTPγS binding studies in rat striatal membranes, SB-616234-A acted as a high affinity antagonist with an apparent pK_B of 8.4 ± 0.5, again whilst providing no evidence of agonist activity in this system. SB-616234-A (1 μM) potentiated electrically stimulated [³H]-5-HT release from guinea pig and rat cortical slices (S₂/S₁ ratios of 1.8 and 1.6, respectively). SB-616234-A (0.3–30 mg kg⁻¹ p.o.) caused a dose-dependent inhibition of ex vivo [³H]-GR125743 binding to rat striatal 5-HT_1B receptors with an ED₅₀ of 2.83 ± 0.39 mg kg⁻¹ p.o. Taken together these data suggest that SB-616234-A is a potent and selective 5-HT_1B autoreceptor antagonist that occupies central 5-HT_1B receptors in vivo following oral administration.