氯沙坦的合成

目的：探索氨沙坦新的合成方法。方法：以戊腈为原料，经3步反应制备中间体4，以2-氰基-4＇-甲基联苯为原料，经3步反应制备中间体8。中间体4与8经N-烷基化反应、还原反应、脱三苯甲基合成了目标化合物氯沙坦。结果：目标物经红外光谱、核磁共振氢谱、质谱和元素分析确证其化学结构，以戊腈计总收率达51.8％。结论：该方法原料易得，操作简便，易于工业化生产。     

阿那曲唑合成工艺改进

目的改进芳香化酶抑制剂阿那曲唑的合成工艺。方法以3,5-二甲基苯甲酸为起始原料,经过酯化、溴化、氰化、甲基化、还原、氯代、N-烷基化和去氨基化合成阿那曲唑。结果产物结构经1H-NMR和MS确证。八步反应的总收率为24.2%。结论改进后的合成方法操作简便,适合工业化生产。     

米氮平的合成

目的：合成去甲肾上腺素能和特异性5-羟色胺能抗抑郁药米氮平。方法：以苯甲酰甲酸甲酯和N-甲基乙二胺为原料经环合、还原、N-烷基化、水解、还原制得米氮平，并通过改变反应溶剂、催化剂和结晶试剂以及后咎理对其合成工艺进行改进。结果：得到的产品经IR，^1H-NMR，MS和元素分析，证明是米氮平。结论：本法收率和质量都有明显提高。     

抗癌药雷替曲塞的合成

目的研究抗癌药雷替曲塞的合成。方法以2-噻吩甲醛为起始原料,经硝化、氧化、酯化、还原、氨基保护、N-甲基化、水解、缩合、脱保护、N-烷基化、水解11步反应合成雷替曲塞。结果与结论总收率为12.9%,其结构经核磁共振氢谱、质谱确证。     

硝酸异康唑的合成新工艺

目的 文中阐述了硝酸异康唑的新的合成工艺。方法 该新的合成工艺由三氯苯乙酮为起始原料经过还原、N-烷基化,成醚和精制四步合成硝酸异康唑。结果 该反应原料易得,反应简单可行,总收率达到47.1%。结论 该工艺为硝酸异康唑的工业化生产提供了依据,为抗真菌医药行业做出了贡献。     

奈非西坦的合成

目的 合成奈非西坦。方法 以2，6-二甲基苯胺为起始原料，经氯乙酰氯N-酰化反应和2-吡咯烷酮的N-烷基化反应合成了奈非西坦。结果 总收率89．9％。对奈非西坦进行了IR，^1H NMR，^13C NMR，MS确证。结论该合成工艺可行，具有工业生产价值。     

盐酸坦索罗辛的合成

以4-甲氧基苯丙酮为原料,依次经过(R)-苯乙胺诱导的还原胺化、氯乙酰化、氯磺化和氨化反应制得N-(R)-[2-(4-甲氧基-3-氨基磺酰基苯基)-1-甲基乙基]-N-(R)-(1-苯乙基)-氯乙酰胺,再经烷基化、还原和催化脱苄等反应制得盐酸坦索罗辛,总收率约15%.     

厄洛替尼的合成工艺改进

目的研究和优化厄洛替尼的合成工艺。方法以3,4-二羟基苯甲酸乙酯和2-氯乙基甲醚为起始原料,经O-烷基化、硝化、还原、环合、卤代和N-烷基化6步反应制得厄洛替尼。结果总收率为56.8%(以3,4-二羟基苯甲酸乙酯计),纯度大于99%(HPLC法)。结论该合成路线工艺稳定、环境污染小、成本低,有利于工业化生产。     

卢帕他定的合成

目的:合成卢帕他定.方法:以氯雷他定为原料,经水解、烷基化2步反应合成卢帕他定.结果:合成了卢帕他定,总收率32.4%.结论:本方法可以方便地得到卢帕他定,简化了操作,缩短了反应周期.     

抗抑郁药米氮平的新合成方法

目的：合成抗抑郁药米氮平。方法：以N-甲基乙醇胺、氧化苯乙烯和2-氨基烟酸为原料，经亲核开环、氯代、碱化、还原、胺烷基化和环合6步制得了抗抑郁药米氮平。结果：文献报道的相应各步反应条件得以优化，产率由22．6％提高到49．5％，各中间体及产物经红外光谱、核磁共振氢谱确证。结论：本方法简化了操作步骤，优化了反应条件，降低了成本，提高了收率。     

吡贝地尔的合成工艺研究

目的 改进吡贝地尔的合成工艺。方法 以邻苯二酚和二氯甲烷为原料经环和反应合成胡椒环,胡椒环与多聚甲醛经Blanc氯甲基化反应合成重要中间体胡椒基氯(3);以哌嗪和二氯嘧啶为原料经氮烷基化反应合成重要中间体1-(2-嘧啶基)哌嗪(4);(3)和(4)经氮烷基化反应得到目标化合物。结果与讨论 目标化合物的结构经1H-NMR、GC-MS谱确证,总收率为44.2%,改进后的工艺操作简便,成本低廉,有利于工业化生产。     

Synthesis and antiinflammatory activity of various 1,4-benzothiazine derivatives

A new series of dihydro-4H-1,4-benzothiazine derivatives was prepared. These compounds were obtained by reductive N-alkylation reaction with sodium borohydride in acetic acid of the corresponding 4H-1,4-benzothiazine. Some of the latter compounds were synthesized by a new synthetic method employing 2-aminobenzenethiol and alkynes as starting material. Preliminary pharmacological data on the antiinflammatory activity of these compounds by using carrageenin paw edema assay are reported.     

Suppression of the histamine-induced wheal and flare response by fexofenadine HCl 60 mg twice daily, loratadine 10 mg once daily and placebo in healthy Japanese volunteers

BACKGROUND: The effects of the selective H1-receptor antagonist fexofenadine have been widely demonstrated in Western populations; however, to date, limited data comparing the effects of fexofenadine with other antihistamines have been reported in Japanese subjects. OBJECTIVE: To investigate the effect of fexofenadine and loratadine on the histamine-induced cutaneous wheal and flare response in healthy Japanese volunteers. METHODS: Eighteen healthy male and female Japanese volunteers aged 20-53 years were randomized to receive fexofenadine HCl 60 mg twice daily, loratadine 10 mg once daily or placebo in a 1-day, three-period, double-blind, crossover study. For each treatment, the wheal and flare response to 100 mg/mL histamine was assessed at baseline and at 1, 1.5, 2, 2.5, 3, 3.5, 4, 8, 12 and 24 hours post-dose. Blood samples were taken for pharmacokinetic analysis. RESULTS: Fexofenadine produced significantly greater percentage suppression of the overall wheal response compared with placebo and loratadine (43.1% versus 10.0% and 15.2%, respectively; p < 0.001). Similarly, fexofenadine significantly suppressed the overall flare response compared with placebo and loratadine (43.0% versus 3.5% and -8.9%, respectively; p < 0.01). Loratadine was statistically no different from placebo in terms of both overall wheal and flare suppression. Area under the curve analysis for wheal and flare reduction (0-12 hours post-dose) confirmed these findings. For wheal inhibition, fexofenadine had a significantly faster onset of action (defined as time to > or = 35% inhibition) compared with placebo (p < 0.001) and loratadine (p < 0.01); for flare, fexofenadine had a significantly faster onset of action than loratadine (p < 0.01). Mean maximum inhibition (the mean of the greatest inhibition achieved from baseline for each treatment) for wheal was achieved significantly faster with fexofenadine than loratadine (p < 0.01), and fexofenadine had a significantly longer duration of effect on suppressing wheal and flare compared with placebo and loratadine (p < 0.05 for all). The antihistamine effects of fexofenadine correlated significantly with its Cmax, while loratadine activity did not correlate significantly with its plasma levels. CONCLUSIONS: Fexofenadine is a potent suppressor of the histamine-induced wheal and flare response in healthy Japanese volunteers. These results support findings in Caucasian subjects, and confirm that fexofenadine has greater antihistaminergic activity than loratadine in this human model.     

Effect of fruit juices on the oral bioavailability of fexofenadine in rats

Fexofenadine has been identified as a substrate for both the efflux transporter, P-glycoprotein (P-gp), as well as the influx transporter, organic anion transporting polypeptide (OATP). Clinical studies in humans showed that fruit juices reduced the oral bioavailability of fexofenadine by preferentially inhibiting OATP over P-gp. The objective of this study was to investigate the effects of fruit juices on the oral absorption of fexofenadine in rats to establish a preclinical fruit juice-drug interaction model. In rats, fexofenadine was excreted unchanged in the urine, bile, and gastrointestinal tract, indicating minimal metabolism, making it an ideal probe to study transport processes. Coadministration of fexofenadine with ketoconazole, a P-gp inhibitor, increased the oral exposure of fexofenadine by 187%. In contrast, coadministration of fexofenadine with orange juice or apple juice to rats decreased the oral exposure of fexofenadine by 31 and 22%, respectively. Increasing the quantity of orange or apple juice administered further decreased the oral exposure of fexofenadine, by 40 and 28%, respectively. This reduction in fexofenadine bioavailability was moderate compared to that seen in humans. These findings suggest that in rats fruit juices may also preferentially inhibit OATP rather than P-gp-mediated transport in fexofenadine oral absorption, albeit to a lesser extent than observed in humans. This fruit juice--drug interaction rat model may be useful in prediction of potential food--drug interactions in humans for drug candidates.     

In vivo pharmacological characterisation of bilastine, a potent and selective histamine H1 receptor antagonist

OBJECTIVE: We set out to establish the in vivo histamine H(1) receptor antagonistic (antihistaminic) and antiallergic properties of bilastine. METHODS: In vivo antihistaminic activity experiments consisted of measurement of: inhibition of increase in capillary permeability and reduction in microvascular extravasation and bronchospasm in rats and guinea pigs induced by histamine and other inflammatory mediators; and protection against lethality induced by histamine and other inflammatory mediators in rats. In vivo antiallergic activity experiments consisted of measurement of passive and active cutaneous anaphylactic reactions as well as type III and type IV allergic reactions in sensitised rodents. RESULTS: In the in vivo antihistaminic activity experiments, bilastine was shown to have a positive effect, similar to that of cetirizine and more potent than that of fexofenadine. The results of the in vivo antiallergic activity experiments showed that the properties of bilastine in this setting are similar to those observed for cetirizine and superior to fexofenadine in the model of passive cutaneous anaphylactic reaction. When active cutaneous anaphylactic reaction experiments were conducted, bilastine showed significant activity, less potent than that observed with cetirizine but superior to that of fexofenadine. Evaluation of the type III allergic reaction showed that of the antihistamines only bilastine was able to inhibit oedema in sensitised mice, although its effect in this respect was much less potent than that observed with dexamethasone. In terms of the type IV allergic reaction, neither bilastine, cetirizine nor fexofenadine significantly modified the effect caused by oxazolone. CONCLUSIONS: The results of our in vivo preclinical studies corroborate those obtained from previously conducted in vitro experiments of bilastine, and provide evidence that bilastine possesses antihistaminic as well as antiallergic properties, with similar potency to cetirizine and superior potency to fexofenadine.     

The effects of fexofenadine on eosinophilia and systemic anaphylaxis in mice infected with Trichinella spiralis

BACKGROUND: The effects of the non-impairing, H(1)-receptor antagonist fexofenadine were investigated in in vivo mouse models of eosinophilia and systemic anaphylaxis. METHODS: Eosinophilia was investigated in C57BL/6 mice (n=5 per group) infected with Trichinella spiralis, with and without administration of fexofenadine HCl (5, 10 and 20 mg/kg/day). Eosinophilia was also studied, with and without fexofenadine administration, in mice with a congenital mast-cell deficiency (W/W(v)) and controls (+/+). The effect of fexofenadine HCl (20 mg/kg/day) on IL-5 and eotaxin blood levels was also investigated in C57BL/6 mice. In a separate model, systemic anaphylaxis was induced in C57BL/6 mice using T. spiralis antigen. Fexofenadine HCl (5, 10 and 20 mg/kg) or vehicle was administered 20 min before antigen challenge (n=5 per group). The effect of fexofenadine on systemic anaphylaxis caused by IgE and anti-IgE was also examined in CBF1 mice injected with serum from NC/Nga mice with high IgE levels. Rectal temperature was measured as an indicator of anaphylaxis. RESULTS: In C57BL/6 mice, repetitive oral administration of fexofenadine HCl (5, 10 and 20 mg/kg/day) resulted in dose-dependent suppression of eosinophilia (p<0.05-0.0001). No suppression was observed in mast-cell deficient W/W(v) mice. In addition, single oral administration of fexofenadine HCl (10 and 20 mg/kg) significantly suppressed the decrease in rectal temperature (p<0.01), a marker for systemic anaphylaxis, in C57BL/6 mice. In CBF1 mice injected with serum from NC/Nga mice with high IgE levels, the decrease in rectal temperature was suppressed by single administration of fexofenadine HCl (10 and 20 mg/kg; p<0.01 and p<0.001, respectively). Fexofenadine had no effect on peripheral IL-5 and eotaxin levels. CONCLUSION: These results indicate that fexofenadine suppresses both eosinophilia and systemic anaphylaxis, both of which are fundamental reactions in allergic diseases.     

Facial thermography is a sensitive tool to determine antihistaminic activity: comparison of levocetirizine and fexofenadine

AIMS: To assess the antihistaminic activity of levocetirizine and fexofenadine 2 h and 24 h after drug administration using facial thermography and to compare the results with those using well-established parameters of antihistaminic activity in the nose and skin. METHODS: This was a randomized, double-blind, three-treatment, three-period, single-dose, cross-over study in healthy males taking levocetirizine 5 mg, fexofenadine 120 mg or placebo. The primary endpoint was nasal skin temperature after nasal histamine challenge recorded for 20 min at 2 and 24 h after drug intake. The secondary endpoints were nasal symptoms and a histamine skin prick test. RESULTS: Thirty subjects were randomized. At 2 h after drug intake the inhibition of the nasal temperature increase from baseline was not significantly different between levocetirizine and fexofenadine. At 24 h it was significantly more pronounced after levocetirizine than fexofenadine (difference: least-squares mean: -0.13 degrees C; P < or = 0.024, 95% CI -0.24, -0.02). Both drugs significantly reduced (P < or = 0.001) the mean temperature increase from baseline compared with placebo at 2 and 24 h (least-squares mean increase and (95% CI): levocetirizine, -0.28 degrees C (-0.42, -0.14) and -0.32 degrees C (-0.43, -0.21); fexofenadine -0.35 degrees C (-0.49, -0.21) and -0.19 degrees C (-0.30, -0.08), respectively). Results of nasal symptom score and wheal and flare were consistent with the thermography results. CONCLUSIONS: Facial thermography is an objective, non-invasive and sensitive method to study antihistaminic activity at the nose level. Levocetirizine and fexofenadine demonstrate the same activity at 2 h after drug intake, but levocetirizine has a more sustained activity at 24 h.     

Enantioselective uptake of fexofenadine by Caco‐2 cells as model intestinal epithelial cells

Objectives Fexofenadine contains a chiral carbon in its chemical structure and is orally administered as a racemic mixture. This study evaluated the selective uptake of fexofenadine enantiomers by Caco‐2 cells as a model of intestinal epithelial cells. Methods R(+)‐fexofenadine or S(?)‐fexofenadine was applied to Caco‐2 cells, followed by incubation. After incubation, the amounts of fexofenadine enantiomers in cells were determined. The kinetic parameters for the uptake of fexofenadine enantiomers by Caco‐2 cells were estimated using the Michaelis–Menten equation. Key findings The transporter‐mediated uptake rate of R(+)‐fexofenadine was 1.7‐fold higher than that of S(?)‐fexofenadine. The difference in transporter‐mediated R(+)‐fexofenadine and S(?)‐fexofenadine uptake was completely diminished under ATP‐depleted conditions and in the presence of organic anion transporter peptide (OATP) inhibitors. Also, a Dixon plot showed that each fexofenadine enantiomer was competitively inhibited by the other enantiomer. The ratio of R(+)‐fexofenadine uptake to S(?)‐fexofenadine uptake in the case of a racemic mixture was higher than that in the case of a single enantiomer. Conclusion This study suggested that the selective absorption of fexofenadine enantiomers by intestinal epithelial cells might have been due to the selective uptake mediated by OATPs and that the difference in intestinal absorption was enhanced with a racemic mixture.     

Comparative study of acute effects of single doses of fexofenadine, olopatadine, d-chlorpheniramine and placebo on psychomotor function in healthy volunteers

Since most classical (first-generation) antihistamines have undesirable sedative effects on the central nervous system (CNS), newer (second-generation) antihistamines have been developed to relieve the sedative effects and to improve the patient's quality of life. However, the psychomotor profiles of second-generation antihistamines are not fully elucidated. In this randomized, double-blind, crossover study, the acute effects of single doses of second-generation antihistamines, fexofenadine (120 mg) and olopatadine (10 mg), on cognitive and psychomotor performance were investigated in comparison with those of placebo and d-chlorpheniramine (4 mg), a first-generation antihistamine, using objective and subjective assessments, in 11 healthy Japanese volunteers. In a battery of psychomotor tests, d-chlorpheniramine impaired tracking ability in the compensatory tracking task and caused a reduction in behavioural activity as continuously measured by wrist actigraphy. Olopatadine, like d-chlorpheniramine, reduced the behavioural activity, while fexofenadine had no effect in any of the tests. No significant changes in the subjects' self-ratings of drowsiness were found with the three antihistamines. These results suggest that d-chlorpheniramine and olopatadine, but not fexofenadine, produce sedative effects on psychomotor performance, and that the CNS profile of fexofenadine is different from that of olopatadine.     

Stability-indicating HPLC Method for Simultaneous Determination of Montelukast and Fexofenadine Hydrochloride

A simple, specific, accurate, and stability-indicating reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of montelukast and fexofenadine hydrochloride, using a Lichrospher^® 100, RP-18e column and a mobile phase composed of methanol:0.1% o-phosphoric acid (90:10 v/v), pH 6.8. The retention times of montelukast and fexofenadine hydrochloride were found to be 10.16 and 12.03 min, respectively. Linearity was established for montelukast and fexofenadine hydrochloride in the range of 2-10 μg/ml and 24-120 μg/ml, respectively. The percentage recoveries of montelukast and fexofenadine hydrochloride were found to be in the range of 99.09 and 99.81%, respectively. Both the drugs were subjected to acid and base hydrolysis, oxidation, photolytic, and thermal degradation conditions. The degradation products of montelukast and fexofenadine hydrochloride were well resolved from the pure drug with significant differences in their retention time values. This method can be successfully employed for simultaneous quantitative analysis of montelukast and fexofenadine hydrochloride in bulk drugs and formulations.