Combination effects of O-carboxymethyl-O-ethyl-β-cyclodextrin and penetration enhancer HPE-101 on transdermal delivery of prostaglandin E1 in hairless mice

An inclusion complex of prostaglandin E₁ (PGE₁) with β-cyclodextrin (β-Cyd) or O-carboxymethyl-O-ethyl-β-cyclodextrin (CME-β-CyD) was made as topical preparations in a fatty alcohol/propylene glycol ointment base. When the PGE₁ preparations were applied onto the skin of hairless mice, the vasodilating effect of the PGE₁-CME-β-CyD complex supplemented with a penetration enhancer, 1-[2-(decylthio)ethyl] azacyclopentane-2-one (HPE-101) was approximately 100 times that of the PGE₁ alone and approximately 10 times that of PGE₁ with HPE-101 or the PGE₁-β-CyD complex with HPE-101. The combination of CME-β-CyD and HPE-101 enhanced the percutaneous penetration of PGE₁ in a synergistic manner; CME-β-CyD assisted the release of HPE-101 from the ointment base and its entry into the skin which may facilitate the percutaneous penetration of PGE₁. Furthermore, this combination suppressed the bioconversion of PGE₁ to give less pharmacologically active metabolites during the passage through the skin, a situation delivering intact PGE₁ more effectively to the site of action. The present data suggest that the combination of CME-β-CyD and HPE-101 is particularly useful for improving topical bioavailability of PGE₁.     

Evaluation of In-vivo Transdermal Absorption of Cyclosporin with Absorption Enhancer Using Intradermal Microdialysis in Rats

The purpose of this study was to evaluate the effect of absorption enhancer on in-vivo transdermal absorption of cyclosporin using intradermal microdialysis in rats. Cyclosporin oily solutions (0.5, 2, 8% w/v) were prepared from Sandimmun (10% w/v oily oral preparation of cyclosporin) by diluting with olive oil. 1-[2-(Decylthio)ethyl]azacyclopentan-2-one (HPE-101) and glycerin were added to the cyclosporin formulation as an absorption enhancer at various concentrations between 1 and 20%. These formulations were applied to the shaved abdomen of rats treated with intradermal microdialysis at a flow rate of 2.5 μL min^?1 for 6 h. Cyclosporin was immediately detected and attained a plateau in the dermal dialysate after topical application of cyclosporin oily solution alone. Cyclosporin levels in the dialysate increased with increasing cyclosporin concentrations in the formulation from 0.5 to 8% (w/v). HPE-101 did not influence cyclosporin absorption at concentrations less than 6% (w/v). Addition of 10% (w/v) HPE-101 significantly enhanced an apparent absorption rate of cyclosporin by 4.9 times. However, 20% (w/v) HPE-101 did not show the enhancing activity. On the other hand, addition of glycerin at concentrations of 6, 10, and 20% (v/v) significantly enhanced an apparent absorption rate of cyclosporin by 3.0, 64, and 6.9 times, respectively. The time lag for cyclosporin absorption was less than 0.21 h in all tested cases. This microdialysis study shows that glycerin is a suitable enhancer for improving the in-vivo cyclosporin absorption from the skin.     

Effects of HPE-101, a skin penetration enhancer, on human erythrocyte membranes

The primary aim of this study was to investigate the skin permeation-enhancing mechanism of HPE-101 using erythrocyte ghost cells prepared from human whole blood as a biomembrane model. The extent of hemolysis of erythrocytes induced by HPE-101 was measured using a spectrophotometer at 540nm. The effect of HPE-101 on lipid fluidity was examined by observing the change of intramolecular excimer formation and fluorescence polarization using an intramolecular probe (1,3-bis(pyrene) propane) and a lipid probe (1,6-diphenyl 1,3,5-hexatriene), respectively. Hemolysis of erythrocytes was observed at 0.01mM and completed at 1.0mM of HPE-101. The fluorescence polarization of the ghost membrane decreased with the addition of HPE-101, whereas the intramolecular excimer formation increased. HPE-101 thus enhanced the rotational mobility and the lateral diffusion, thereby decreasing the microviscosity of ghost membranes, implying that HPE-101 increases the lipid fluidity of ghost membranes. Therefore, HPE-101 seems to cause an increase in fluidity of the lipid bilayers in the stratum corneum of the skin, resulting in the reduction of diffusion resistance.     

Further Evaluation of a New Penetration Enhancer,HPE-101

Abstract— The penetration enhancer, 1-[2-(decylthio)ethyl]azacyclopentan-2-one (HPE-101), significantly enhanced the excretion of topically applied [¹⁴C]indomethacin when dissolved in dipropylene glycol, triethylene glycol, diethylene glycol, 1,3-butylene glycol, trimethylene glycol, glycerin, water, silicone or triethanolamine, but not when dissolved in ethanol, isopropyl alcohol, oleyl alcohol, olive oil, peppermint oil, isopropyl myristate or hexylene glycol. HPE-101 significantly enhanced the excretion of [¹⁴C]indomethacin, [¹⁴C]nicotinic acid, [¹⁴C]5-fluorouracil, [³H]oestradiol and [³H]triamcinolone acetonide, but not that of [³H]testosterone. HPE-101 also significantly enhanced the excretion of [¹⁴C]indomethacin applied to intact skin of rabbit, guinea-pig and rat, and to tape-stripped skin of guinea-pig, but did not enhance the excretion of [¹⁴C]indomethacin applied to tape-stripped skin of rat or rabbit.     

Influence of cyclodextrin complexation on the in vitro permeation and skin metabolism of dexamethasone

The influence of complexation of a model drug, dexamethasone acetate (DMA), with beta-cyclodextrin (beta-CyD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) on the in vitro permeation through hairless mouse skin and on skin metabolism have been investigated. Complexation with CyDs increased the amount of DMA permeated in the order of 2.0 and 3.0 times for beta-CyD and HP-beta-CyD, respectively. The partition coefficient, between stratum corneum and buffer (K(SC/buffer)), for DMA decreased when the drug was an inclusion complex, being greatest for DMA/HP-beta-CyD complex. Complexation protected the drug against skin metabolism. The increase of skin permeation and stability of the model drug in the skin suggest that the complexation with beta-CyD and HP-beta-CyD is a rational way to improve the physical-chemical properties of drugs for use in transdermal delivery systems.     

Improvement of solubility and oral bioavailability of rutin by complexation with 2-hydroxypropyl-beta-cyclodextrin

The object of this study was to enhance the solubility, dissolution rate, and oral bioavailability of rutin by complexation with 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD). The interaction of rutin with cyclodextrins (CyDs) was evaluated by the solubility, and ultraviolet (UV) and circular dichroism (CD) spectrophotometries. The chemical and enzymatic stability of rutin was examined in an alkaline buffer solution and in rat small intestinal homogenates, respectively. Dissolution rates of rutin and its CyD complexes were measured by the dispersed amount method. In vivo absorption studies of rutin after oral administration via conventional tablet containing rutin alone or its beta-CyD complexes was performed on beagle dogs. The stability constants calculated from the phase solubility method increased in the order of HP-gamma-CyD < G2-beta-CyD < beta-CyD < HP-beta-CyD. Spectroscopic studies also revealed that HP-beta-CyD and beta-CyD formed a relatively more stable inclusion complex with rutin. The dissolution rates of rutin increased by the complexation with CyDs in the order of rutin alone < HP-beta-CyD < or = beta-CyD. HP-beta-CyD inhibited the hydrolysis of rutin in the alkaline buffer solution and the small intestinal homogenates of rats, suggesting that HP-beta-CyD may stabilize rutin in a gastrointestinal tract after oral administration. When the tablet containing rutin or its beta-CyD complexes was administered to beagle dogs, the plasma levels of homovanillic acid (HVA) (a major stable metabolite of rutin) after oral administration of HP-beta-CyD complex were much higher than in either that of rutin alone or in its beta-CyD complex. The in vivo absorption study suggests that HP-beta-CyD increased the oral bioavailability of rutin from the gastrointestinal tracts of beagle dogs because of the increase in solubility, faster dissolution rate, and gastrointestinal stability. HP-beta-CyD has a significant advantage with respect to providing high aqueous solubility while maintaining a lack of toxicity in oral pharmaceutical preparations of rutin.     

Mechanisms underlying the inhibitory actions of the pentacyclic triterpene alpha-amyrin in the mouse skin inflammation induced by phorbol ester 12-O-tetradecanoylphorbol-13-acetate

The present study evaluated some of the mechanisms through which alpha-amyrin, a pentacyclic triterpene isolated from Protium Kleinii and other plants, exerts its effects against 12-O-tetradecanoylphorbol-acetate (TPA)-induced skin inflammation in mice. Topical application of alpha-amyrin (0.1-1 mg/ear) dose-dependently inhibited TPA-induced increase of prostaglandin E2 (PGE2) levels. In contrast with the selective cyclooxygenase (COX)-1 SC560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethylpyrazole] or COX-2 rofecoxib inhibitors, alpha-amyrin failed to alter either COX-1 or COX-2 activities in vitro. Western blot analysis revealed that alpha-amyrin dose-dependently inhibited TPA-induced COX-2 expression in the mouse skin. The evaluation of nuclear factor-kappaB (NF-kappaB) pathway revealed that topical treatment with alpha-amyrin is able to prevent IkappaB alpha degradation, p65/RelA phosphorylation and NF-kappaB activation. Moreover, alpha-amyrin given topically dose-dependently inhibited the activation of upstream protein kinases, namely extracellular signal-regulated protein kinase (ERK), p38 mitogen-activated protein kinase (MAPK) and protein kinase C (PKC)alpha, following topical TPA treatment. Collectively, present results suggest that topical skin application of alpha-amyrin exerts a strong and rapid onset inhibition of TPA-induced inflammation. These effects seem to be associated with the suppression of skin PGE2 levels by mechanisms involving the suppression of COX-2 expression, via inhibition of upstream protein kinases--namely ERK, p38 MAPK and PKCalpha--and blocking of NF-kappaB activation. These results indicate that alpha-amyrin-derivative could be potentially relevant for the development of a topical agent for the management of inflammatory diseases.     

Specific augmentation of plantar skin blood flow by lipo-PGE1 assessed in tetrodotoxin- and N(G)-nitro-L-arginine-treated rats

1Vasodilating effects of prostaglandin E1 incorporated in lipid microspheres (lipo-PGE1) were compared with those of prostaglandin E1 (PGE1) or its cyclodextrin clathrated preparation (PGE1-CD) on plantar skin blood flow in rats treated with tetrodotoxin and N(G)-nitro-L-arginine (L-NNA). Tetrodotoxin (50 microg/kg, i.v.) could totally inhibit the pressor response to electrical stimulation of the spinal cord, and the reflex tachycardia due to the depressor response to acetylcholine. Furthermore, L-NNA (30 mg/kg, i.v.) was used to counteract the lowering of the systemic blood pressure and peripheral vascular tone by elimination of sympathetic nerve activity, and to maintain the arterial blood pressure at the control level. Lipo-PGE1 increased plantar skin blood flow 4 to 6 times more potently than PGE1-CD or PGE1 in the treated rats. Furthermore, lipo-PGE1 increased plantar skin blood flow about 3 times more selectively than PGE1-CD. We also assessed several vasodilators, including terbutaline, nitroprusside, nicardipine, and papaverine in tetrodotoxin- and L-NNA-treated rats. However, none of them could selectively increase plantar blood flow despite the prominent depressor responses achieved. These results suggest that PGE1 preparations, especially lipo-PGE1 could potently and selectively increase plantar skin blood flow in rats treated with tetrodotoxin and L-NNA.     

Application of in Vivo Microdialysis to Transdermal Absorption of Methotrexate in Rats

Microdialysis was applied to determine the in vivo transdermal absorption of methotrexate (MTX) in rats with or without a new penetration enhancer, l-[2-(decylthio)ethyl]azacyclopentan-2-one (HPE-101). A solution composed of 2.5 mM MTX and 3% (w/v) HPE-101 was applied to the shaved abdomen, in which a semipermeable membrane cannula of 10-mm length was inserted intracutaneously with the use of an L-shaped needle. Intradermal microdialysis was performed at a flow rate of 1.0 µL/min for 12 hr. The concentration of MTX in the dialysate was measured by fluorescence polarization immunoassay (FPIA). HPE-101 (3%, w/v) significantly increased the dermal MTX concentration from 0.06±0.04 µM in the control to 56±26 µM in the dialysate from 8 to 12 hr. HPE-101 at concentrations of 0.75, 1.5, 2.25, and 3% (w/v) enhanced the total recovery of MTX in dermal dialysate from 0 to 10 hr by approximately 5, 18, 42, and 500 times compared with the control, respectively. The microdialysis system is useful for assessing in vivo transdermal drug absorption.     

Pep-1 peptide-conjugated elastic liposomal formulation of taxifolin glycoside for the treatment of atopic dermatitis in NC/Nga mice

In order to develop topical preparations of taxifolin glycoside (TXG) for the treatment of atopic dermatitis (AD), formulations of Pep-1 peptide-conjugated elastic liposomes (Pep1-EL) were examined for their in vitro skin permeation profile and in vivo therapeutic efficacy. TXG-loaded Pep1-EL - a nanovesicle consisting of phosphatidylcholine, Tween 80, N-[4-(p-maleimidophenyl)butyryl]-phosphatidylethanolamine (MPB-PE), and Pep-1 peptide - is 130nm in size, and has a zeta potential of 25mV and a deformability index value of 60. Here, we examined the skin permeability of several topical preparations using a Franz diffusion cell mounted with depilated mouse skin and found that formulations of Pep1-EL exhibited superior absorption when compared to aqueous solution, EL or Pep-1 peptide-admixed EL formulations. Both transepidermal water loss and skin surface hydration were also measured using AD-induced NC/Nga mice, and the TXG-loaded Pep1-EL treatment group displayed a significantly expedited recovery in skin barrier function when compared to the controls treated with a TXG aqueous solution (p<0.05). AD-associated immune responses - including serum interleukine-4, immunoglobulin E, and interferon-gamma - were also regulated by topical application of TXG-loaded Pep1-EL. In conclusion, the novel Pep1-EL formulation of TXG shows substantial promise in the treatment of AD as a result of its desirable skin delivery-promoting capability.     

Moisture adsorption-desorption effect on the structure of inclusion complex of 6-chloro-2-pyridylmethyl nitrate and beta-cyclodextrin

A new anti-anginal drug, 6-chloro-2-pyridylmethyl nitrate (FR46171), was found to form a complex with beta-cyclodextrin (beta-CyD), molecular ratio 1:1. The FR46171/beta-CyD complex thus prepared showed a moisture adsorption-desorption hysteresis characteristic of hydrophilic polymers. The moisture adsorption-desorption isotherm and differential scanning calorimetry indicated that the moisture adsorbed FR46171/beta-CyD complex includes 13-15 mol of water while the moisture desorbed complex includes 5 mol of water. X-ray diffraction patterns of these samples confirmed their different structures. The scanning electron photomicrographs and the surface areas (BET) suggested that the moisture adsorption-desorption hysteresis observed in FR46171/beta-CyD complex can be attributed to reversible hydrogen bonding between water molecules and hydroxyl groups.     

Interference of WEB 2086 and BN 52021 with Paf-induced effects on guinea-pig trachea.

1. The thienotriazolodiazepine WEB 2086 and the gingkolide BN52021 have been evaluated as antagonists of Paf-acether (Paf) by studying their effects on Paf-induced relaxation and Paf-induced prostaglandin E2 (PGE2) production in histamine-contracted guinea-pig tracheal preparations. 2. Relaxation induced by Paf 4 microM in histamine-contracted guinea-pig tracheal preparations was 39.67 +/- 3.5% (n = 30). At the same concentration, Paf significantly increased PGE2 production from histamine-contracted guinea-pig tracheal preparations. 3. WEB 2086 inhibited in a dose-related manner (IC50 = 21.2 nM) the relaxant effect induced by Paf and, at 1 microM, suppressed Paf-induced release of PGE2. 4. BN 52021 100 microM inhibited to about 60% Paf-induced relaxation of histamine-contracted guinea-pig tracheal preparations, but completely abolished Paf-induced increase in PGE2. 5. Both antagonists had no effects on relaxations induced by arachidonic acid 10 microM or PGE2 0.1-1 microM in histamine-contracted guinea-pig tracheal preparations. 6. The results are consistent with the presence of specific Paf receptors in guinea-pig trachea and indicate that a relaxant prostanoid, namely PGE2, at least partially mediates Paf-induced relaxation in this experimental model.     

Inclusion complex formation of captopril with alpha- and beta-cyclodextrins in aqueous solution: NMR spectroscopic and molecular dynamic studies

The inclusion complex formation of alpha-cyclodextrin (alpha-CyD), beta-cyclodextrin (beta-CyD), and 2-hydroxylpropyl-beta-cyclodextrin (HP-beta-CyD) with an angiotensin converting enzyme inhibitor, captopril, in aqueous solution was studied by (1)H- and (13)C-nuclear magnetic resonance spectroscopies, including ROESY and GROESY techniques, by kinetic methods and by molecular dynamic calculations. The oxidative degradation of captopril was markedly suppressed in alpha-CyD solutions, whereas beta-CyD and HP-beta-CyD had negligible stabilizing effects. These NMR and kinetic results suggested that alpha-CyD includes preferably the propyl thioalcohol moiety of captopril, depositing the proline moiety outside the cavity. On the other hand, beta-CyD includes a whole molecule of captopril in the cavity, locating the carboxylic acid within the cavity and the terminal thiol moiety outside the cavity. These inclusion structures were supported by molecular dynamic studies.     

Topical delivery of cyclosporin A: an in vitro study using monoolein as a penetration enhancer.

Topical delivery of cyclosporin A (CysA) is of great interest for the treatment of autoimmune skin disorders, but it is frequently ineffective due to poor drug penetration in the skin. The present study was aimed at investigating whether the presence of monoolein (a lipidic penetration enhancer) in a preparation of propylene glycol can improve CysA delivery to the skin. CysA was incorporated in a propylene glycol preparation containing 5-70% (w/w) of monoolein. The topical (to the skin) and transdermal (across the skin) delivery of CysA were evaluated in vitro using porcine ear skin mounted in a Franz diffusion cell. CysA was quantified by UV-HPLC. At 5%, monoolein increased only the transdermal delivery of CysA. At 10%, it increased both topical and transdermal delivery. When the concentration of monoolein was further increased (20-70% w/w), an interesting phenomenon was observed: the topical delivery of CysA was still elevated but its transdermal delivery was substantially reduced. It was concluded that monoolein (in propylene glycol formulations) can promote the topical delivery of CysA, with reduced transdermal delivery.     

Spectrophotometric and electrochemical study of the inclusion complex between beta-cyclodextrin and furnidipine

Inclusion complexation between furnidipine (2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-tetrahydrofurfuryl 5-methyl diester), a calcium-channel antagonist, and beta-cyclodextrin (beta-CyD) was studied in aqueous solution by using both spectrophotometric and electrochemical measurements. The phase solubility profile was classified as A(L)-type, indicating the formation of 1:1 stoichiometric inclusion complex of furnidipine with beta-CyD. Based on the spectrophotometric absorbance's variations, a formation constant value, K(f), of 156 M(-1) was determined. Electrochemical measurements using chronocoulometric experiments were used for the determination of the diffusion coefficients. In absence of beta-CyD, a diffusion coefficient value of 4.32 x 10(-6) cm2 s(-1) was obtained for furnidipine. The addition of beta-CyD produced a decrease of 30% for the diffusion coefficient. Formation of inclusion complexes of furnidipine with beta-CyD was proved to increase more than three times the solubility of furnidipine.     

Effect of 2-Hydroxypropyl-β-cyclodextrin on Percutaneous Absorption of Methyl Paraben

A potential use of 2-hydroxypropyl-β-cyclodextrin (HP-β-CyD) to solubilize methyl paraben and to suppress its percutaneous absorption was examined, and compared with nonionic surfactant HCO-60. HP-β-CyD significantly increased the solubility of methyl paraben in water, where the apparent 1:1 stability constant of the soluble complex was determined to be 2150 M^?1. The in-vitro cutaneous permeability of methyl paraben through an isolated skin of hairless mouse was suppressed by HP-β-CyD, thus promoting the bioconversion of methyl paraben to the less toxic metabolite, p-hydroxybenzoic acid (p-HBA) in the epidermis. These effects of HP-β-CyD were greater than those of HCO-60. HP-β-CyD (2% w/v) reduced the in-vivo percutaneous absorption of methyl paraben by 66% 24 h after the topical application of a solution containing [¹⁴C]methyl paraben to hairless mouse skin. Additionally, the percutaneous absorption of [¹⁴C]HP-β-CyD was confirmed to be extremely low. These results suggest that HP-β-CyD is useful in liquid preparations of methyl paraben for topical application.     

Improvement of stability and bioavailability of 1-hexylcarbamoyl-5-fluorouracil (HCFU) by O-carboxymethyl-O-ethyl-beta- cyclodextrin]

The possible utility of O-carboxymethyl-O-ethyl-beta-cyclodextrin (CME-beta-CyD) as a novel drug carrier was studied in vitro and in vivo, by using 1-hexylcarbamoyl-5-fluorouracil (HCFU) as a model drug. The chemical instability of HCFU in solution and solid state was improved by CME-beta-CyD complexation. The in vitro release of HCFU from the CME-beta-CyD complex was decelerated in acidic solution, while accelerated at neutral pH regions, showing a typical delayed-release pattern. This pattern was clearly reflected in the blood levels after the oral administration of the complex to dogs, increasing the bioavailability. The present results suggested that CME-beta-CyD is useful as a delayed-release-type carrier for the oral administration of chemically labile HCFU.     

Design of two liquid Ibuprofen-poloxamer-limonene or menthol preparations for dermal administration

The purpose of our study was to prepare liquid forms of 20% ibuprofen in 30% poloxamer 407, while avoiding gel formation and to assess their drug diffusion-penetration (permeation) into the skin. Two series of poloxamer-based formulations were prepared, both containing ibuprofen and one of two terpenes: d-limonene and 1-menthol. A rheological characterization of all preparations made allowed their grouping in two modalities: gels and fluids. Data revealed a statistically superior enhanced permeation terpene-dependent of ibuprofen in fluid preparations, specially the one containing d-limonene. Cumulative permeation in 24 hr was 2500 micro g/cm(2) and 4500 micro g/cm(2) for the 1-menthol and d-limonene, respectively, for fluid preparations as compared with 2000 micro g/cm(2) and 1600 micro g/ cm(2) for d-limonene and 1-menthol on gels and only 1200 micro g/cm(2) of the control solution (p < 0.05). Results postulate that a liquid 30% poloxamer-based preparation of ibuprofen with d-limonene is possible and that it may be useful as a topical preparation of ibuprofen.     

中药制剂不良反应100例监测分析

目的根据我院患者服用中药制剂之后发生的不良反应,探讨中药毒性与临床合理用药方法,为临床安全用药提供可靠和准确的参考。方法选取我院2011年8月至2013年8月期间服用中药制剂发生不良反应患者病例共100例,回顾性分析患者临床病例报告,统计和总结不良反应发生情况,寻找合理的用药管理对策。结果使用中药制剂后发生不良反应的患者年龄段集中于49⁶0岁,导致患者用药之后发生不良反应的主要中药制剂包括注射剂、外用膏剂和口服制剂等,发生不良反应的服用途径为静脉注射和局部外用给药;患者不良反应病灶主要集中于表皮损害和消化系统伤害。结论中药毒性会导致患者发生不良反应,在临床使用过程中,一定要制定用药管理规定,严密监测用药后的不良反应,提高不良反应控制意识,做好防范工作,降低不良反应发生率。