阿昔莫司缓释片的体外释放度及释放机制的初步研究

目的：研制凝胶骨架型阿昔莫司缓释片，考察其体外释放度，并对药物的释放机制进行初步研究。方法：以羟丙基甲基纤维素(HPMC)为骨架材料，将阿昔莫司制成凝胶骨架型缓释片，考察HPMC种类及用量、填充剂种类及用量和制备工艺等因素对阿昔莫司缓释片体外释放速率的影响。结果：HPMC的种类、用量和片剂表面积对阿昔莫司体外释放速率有明显的影响；填充剂的种类及制备工艺对释放速率基本无影响；篮法、桨法及转速对释放速率基本无影响。阿昔莫司缓释片的释放机制为非纯Fickian扩散(non—Fickian)机制，即为药物扩散和骨架溶蚀协同作用的结果，其中扩散机制起主要支配作用。结论：用高黏度HPMC作为亲水凝胶骨架片基质能达到较好的缓释作用。     

家犬单剂量和多剂量口服阿昔莫司缓释制剂的药代动力学和生物等效性研究

目的研究阿昔莫司缓释片在家犬体内单剂量和多剂量的药代动力学和生物等效性。方法测定6只家犬单剂量和多剂量口服缓释片和普通胶囊后的血药浓度。结果阿昔莫司的药-时曲线符合非隔室模型。单剂量给药后，缓释片和普通胶囊的AUC分别为(158±30)和(147±37) μg·h·mL^-1；T_max分别为(4.3±0.8)和(2.6±1.3) h；C_max分别为(29±6)和(42±10) μg·mL^-1；T_1/2分别为(2.3±0.7)和(1.60±0.10) h；MRT分别为(6.0±0.8)和(3.9±0.7) h；F_r为(108±16)%。多剂量给药后，缓释片和普通胶囊的AUC分别为(209±23)和(195±26) μg·h·mL^-1；T_max分别为(6.3±0.8)和(3.4±1.5) h；C_max分别为(27±4)和(36±5) μg·mL^-1；Cmin分别为(2.2±1.0)和(0.20±0.20) μg·mL^-1；C_av分别为(8.7±1.0)和(8.1±1.1) μg·mL^-1；FI分别为(293±73)%和(448±91)%；F_r为(114±19)%。结论单剂量实验的双单侧检验结果表明：缓释片和普通胶囊生物等效；缓释片具有良好的缓释效果。多剂量实验结果表明：缓释片和普通胶囊生物等效；缓释片的波动系数优于普通胶囊。     

Effects of acipimox and cholestyramine on serum lipoproteins,non-cholesterol sterols and cholesterol absorption and elimination

Summary The hypolipidaemic and metabolic effects of cholestyramine combined with acipimox or placebo have been evaluated in a double-blind ninety-day study in 18 patients with xanthomatous familial hypercholesterolaemia.Serum LDL-cholesterol was reduced by 35% in the cholestyramine group and 39% in the acipimoxcholestyramine group. The latter treatment increased the HDL-cholesterol level. Serum VLDL-cholesterol and triglyceride concentrations were unchanged.Cholesterol absorption efficiency was significantly reduced, and bile acid synthesis and faecal cholesterol elimination in both groups were increased. The metabolic changes were similar in the two treatment groups, but the increase in faecal neutral sterol excretion was significant only when acipimox was added.The serum cholesterol precursor sterol contents were similarly increased during the two treatments, indicating enhancement of endogenous cholesterol synthesis.The decrease in cholesterol absorption and the increase in neutral sterol excretion were more pronounced in subjects with >30% than in those with <30% reduction in LDL-cholesterol.The changes in serum total and LDL-cholesterol levels and cholesterol metabolism were not related to apoE phenotype, but the increase in HDL-cholesterol was higher in E4 then in E3 subjects.     

Increased affinity of LDL for their receptors after acipimox treatment in hypertriglyceridemia

Summary The regulation of cellular LDL metabolism by hypertriglyceridemic LDL was tested before and after treatment with acipimox, a nicotinic acid derivative, in 11 type IV hyperlipidemic patients. Large, less dense LDL particles were found in plasma after acipimox treatment. HDL subfractions were only slightly modified, with an increase of dense, cholesteryl ester-enriched and triglyceride-poor HDL₃ particles. The LDL (B, E) receptor activity in human skin fibroblasts of LDL isolated before and after treatment was also evaluated. Hypertriglyceridemic LDL proved rather inefficient in regulating receptor activity, with a close to 30% lower capacity than normal LDL to inhibit receptor-mediated uptake and degradation of¹²⁵I-LDL. This abnormality was fully corrected after acipimox. The reported findings indicate that acipimox treatment in type IV patients can normalize the defective interaction of hypertriglyceridemic LDL with the LDL (B, E) receptor.     

苯扎贝特与阿西莫司治疗高脂血症的比较

目的 :观察苯扎贝特降低血脂的疗效。方法 :治疗组 4 1例 (男性 2 5例 ,女性 16例 ;年龄 64±s 8a)给苯扎贝特 0 .2 g ,po ,tid× 4wk。对照组 35例(男性 14例 ,女性 2 1例 ;年龄 61± 7a)给阿西莫司0 .2 5g ,po ,tid× 4wk。结果 :苯扎贝特降低血胆固醇 (TC)和三酰甘油 (TG)的总有效率为 84 %和88%。阿西莫司降低血TC和TG的总有效率为77%和 67%。 2药且均有升高高密度脂蛋白胆固醇、载脂蛋白AI/载脂蛋白B10 0 的作用 ,苯扎贝特降低TG的水平高于阿西莫司 (P <0 .0 5)。结论 :苯扎贝特是一个安全、有效的降脂药物 ,特别适用于高TG的治疗     

Acipimox does not augment thallium-201 redistribution in the fasting state

BACKGROUND: Recently oral glucose loading and a thallium-glucose insulin infusion have been used to augment myocardial uptake of thallium-201 (TI-201). Acipimox is a nicotinic-acid derivative that reduces serum free fatty acid (FFA) levels and enhances myocardial glucose uptake. This study was performed to assess the effects of acipimox on TI-201 redistribution. METHODS: Fourteen patients with coronary artery disease underwent 2 successive TI-201 perfusion studies. Stress was performed by adenosine coupled with ergometer exercise. Patients received either 500 mg of acipimox or placebo immediately after stress, and images were acquired. Redistribution imaging was carried out after 4 hours. Patients returned after 7 to 14 days for a repeat stress protocol, receiving the alternate test article. Both studies were carried out under identical conditions with identical medication with the patient in the fasting state. Image analysis was conducted quantitatively with polar plots and by using segmental uptake as a percentage of maximal counts with a 9-segment model. RESULTS: There were no significant differences between the acipimox and placebo arms of the study of hemodynamic parameters. On polar plot analysis, there were no differences between acipimox and placebo for mean values of stress defect extent (97 +/- 16.1 vs 96.5 +/- 18.8 pixels), defect severity (532.2 +/- 120 vs 537 +/- 133.9 standard deviations [SDs]), for defect reversibility (61.7 +/- 18 vs 55.4 +/- 15.3 SDs), and percentage reversibility (21.2% +/- 5.5% vs 19.2% +/- 5.8%), respectively. Similarly, on segmental uptake analysis there was no significant difference between the acipimox and placebo arms with regard to the proportion of segments classified as normal, fixed defect, reversible defect, or reverse redistribution. CONCLUSION: Although acipimox has been shown to augment myocardial glucose uptake and myocardial glucose uptake has been shown to improve cellular uptake of TI-201, in the fasting state acipimox does not enhance the redistribution after stress. This may be because serum insulin levels are not increased by acipimox, and insulin is instrumental in enhancing the joint transport of glucose and TI-201 into myocytes.     

Metabolism of plasma low density lipoproteins in familial combined hyperlipidaemia: effect of acipimox therapy.

Ten male patients with familial combined hyperlipidaemia (FCHL) were studied with regard to LDL metabolism and composition. The FCHL patients had higher LDL levels than healthy controls (5.4 +/- 1.4 vs. 3.7 +/- 0.7 mmol l-1; P < 0.005) and a higher rate of production of the lipoprotein (15.8 +/- 3.1 mg kg-1 d-1 in FCHL vs. 13.1 +/- 1.8 mg kg-1 d-1 in the normals; P < 0.005). The fractional catabolic rate of LDL was low-normal in the FCHL patients, with a high level of interindividual variation. The actual individual LDL cholesterol level within the FCHL patient group appeared to be more closely associated with the LDL apoB FCR value than the rate of production of the particle. Analysis of the LDL particles from FCHL patients revealed a relative enrichment in triglycerides, while the cholesterol content of the lipoprotein was normal. Institution of acipimox therapy in 8 patients reversed the high rate of synthesis of LDL (15.2 +/- 3.5 mg kg-1 d-1) to a more normal level (13.9 +/- 4.0 mg kg-1 d-1; P = 0.08), while the FCR did not change significantly. In conclusion, patients with FCHL show an apparent overproduction of LDL apoB, while the actual degree of LDL elevation appears to be dependent on the clearance capacity of the lipoprotein, measured as LDL apoB FCR. The overproduction defect of LDL apoB can, at least in part, be managed by treatment with the nicotinic acid analogue acipimox.     

新型代谢综合征治疗药物的设计、合成及生物活性评价

目的 设计合成新型代谢综合征治疗药物.方法 以具有降脂活性的阿昔莫司做为基本结构单元,与贝特类药物的"苯氧脂酸类"药效团有机结合,设计了一类新型的苯氧脂肪酸酯类化合物,以对羟基苯胺、对羟基苄胺以及对羟基苯乙胺为原料,首先将氨基保护,然后与相应的卤代脂肪链羧酸酯成醚,然后脱除Boc保护基得到相应的胺类中间体,最后与阿昔莫司成酰胺得目标化合物,并考察了目标化合物对Triton WR-1339所致急性高脂血症小鼠血清甘油三酯和总胆固醇的影响.结果和结论 合成目标化合物5个,均经1H NMR和ESI-MS确证结构正确.初步活性评价结果表明,所合成化合物均具有一定的降脂活性,其中化合物4c的调脂活性与阳性对照苯扎贝特接近,对于新型代谢综合征药物的发现具有积极意义.     

阿昔莫司缓释片的体外释放度与犬体内吸收相关性

目的:研究阿昔莫司缓释片的体外释放度与其在家犬体内吸收的相关性。方法:以水为溶出介质,测定阿昔莫司缓释片的体外释放度。采用高效液相色谱法测定家犬单剂量口服阿昔莫司胶囊和缓释片后的血药浓度,用非隔室模型对阿昔莫司的体内过程进行拟合,以反卷积分法求算积分方程中的输入函数。以输入函数与同时间点体外累积释放度回归求得相关系数并与相关系数临界值进行比较。结果:以累积释放度Y与输入函数R建立的回归方程为:Y=18.118R+35.717(r=0.9309),相关系数临界值r4,0.05=0.811,r>r4,0.05,表明回归方程显著。结论:自制阿昔莫司缓释片体内外相关性良好。     

A pilot study of the long-term effects of acipimox in polycystic ovarian syndrome

BACKGROUND: To evaluate the effects of long-term acipimox administration on glucose-induced insulin secretion and peripheral insulin sensitivity in polycystic ovarian syndrome (PCOS), 20 PCOS subjects (eight lean and 12 obese) and 14 body mass index-matched controls (seven lean and seven obese) were investigated. METHODS: Fasting blood samples were collected for basal hormone and lipoprotein assays, after which patients underwent an oral glucose tolerance test (OGTT). The following day a euglycaemic-hyperinsulinaemic clamp was performed. After 4-6 weeks of treatment with acipimox at a dose of 250 mg given orally three times a day, the patients repeated the study protocol. RESULTS: No significant differences were found in the glucose, insulin or C-peptide responses to OGTT before and after anti-lipolytic drug administration in any group, nor was there any effect on insulin sensitivity. Concerning the lipid profile, acipimox administration led to a significant decrease of cholesterol and low-density lipoprotein levels in obese PCOS patients as well as in obese and lean controls. Lower triglycerides were found after the drug administration in both obese groups. Post-treatment free fatty acid levels were not significantly different when compared with basal values. CONCLUSIONS: Acipimox does not appear to be an effective insulin-lowering drug in PCOS, even if it can be used in obese women with PCOS as an additional therapeutic agent to ameliorate the atherogenic lipid profile of the syndrome.