氢化阿托酸在大鼠体内立体选择性时间药代动力学

以余弦法分析氢化阿托酸(HTA)药代动力学参数证明,下列参数具有昼夜节律:标准明暗周期下,S(+)-HTA的T_1/2β和CL,R(-)-HTA的T_1/2β以及外消旋体的CL和MRT;反相明暗周期下,S(+)-HTA的T_1/2β和AUC,R(-)-体的CL以及外消旋体的CL。下列参数具有立体选择昼夜节律:标准明暗周期下,S(+)-HTA的CL,反相明暗周期下,S(+)-HTA的T_1/2β和AUC以及R(-)-HTA的CL。以外消旋体给药后,大鼠体内由R(-)-体向S(+)-体的转化过程,可出现昼夜节律,在两种明暗周期下,峰值相位均位于黑暗期之末,据此,提出HTA的清晨给药治疗方案。     

青蒿琥酯自微乳在大鼠体内的药动学研究

目的 建立大鼠血浆中青蒿琥酯的HPLC-MS/MS测定方法,并研究青蒿琥酯自微乳在大鼠体内的药动学特征。方法 12只SD大鼠随机分为2组,单剂量分别灌胃（50 mg·kg^-1）青蒿琥酯自微乳和青蒿琥酯原料药,以格列吡嗪为内标,用LC-MS/MS测定给药后血浆中的药物浓度,并计算药动学参数。结果 青蒿琥酯血浆样品的线性范围为1.0~1 000.0 ng·mL^-1,回归方程为A=294.74C-439.33（r=0.999 6）,定量下限为1.0 ng·mL^-1。日内、日间变异系数（RSD）均<10%,符合生物样品的分析要求。青蒿琥酯原料药和青蒿琥酯自微乳的药动学参数C_max、t_1/2和AUC_0→t分别为：（87.6±8.80）ng·mL^-1,（1.88±0.33）h和（43.3±1.74）h·ng·mL^-1;（421±41.6）ng·mL^-1,（1.48±0.17）h和（282±17.7）h·ng·mL^-1。其中,C_max和AUC_0→t存在显著性差异（p<0.01）。结论 该方法简便灵敏,可用于血浆中青蒿琥酯的含量测定,经灌胃给药后,与原料药比较,青蒿琥酯自微乳能显著提高生物利用度。     

间硝苯地平在Beagle犬体内的药代动力学

目的用反相高效液相色谱法研究间硝苯地平(m-nifedipine，m-Nif)在Beagle犬体内的药代动力学特征。方法正交设计优化色谱分离条件，Beagle犬分别iv给予m-Nif 0.288 mg·kg^-1和ig m-Nif 1.152，3.456，10.370 mg·kg^-1。用反相高效液相色谱法分析血浆中原型药物浓度，血浆药物浓度-时间数据用3P97药代动力学软件分析。结果Beagle犬iv m-Nif，其体内过程符合二室模型，T_1/2β为116.8 min；ig给予m-Nif 后在Beagle犬体内的代谢符合一室模型，其中低剂量(1.152 mg·kg^-1)组C_max为20 μg·L^-1， T_1/2(k_e)为147 min；中剂量(3.456 mg·kg^-1)组C_max为36 μg·L^-1，T_1/2(k_e) 为122 min；高剂量(10.37 mg·kg^-1)组C_max为69 μg·L^-1，T_1/2(k_e)为144 min。结论Beagle犬ig和iv m-Nif 后，血浆中药物消除迅速，口服绝对生物利用度较低。     

贝诺酯片剂的研制及生物利用度研究

通过减小药物粒径,提高贝诺酯片剂的生物利用度。在市售片以A(500mg)基础上研制了新处方片剂B(400mg)。建立贝诺酯片剂体外溶出度试验方法,即以表面活性剂溶液作溶出介质,以浆法进行溶出度测定。用HPLC法测定贝诺酯在体内的水解产物水杨酸和扑热息痛的血药浓度。结果表明药物研磨粉碎前后体外溶出速度常数分别为0.0152min-1及0.0337min^-1(P<0.001)。A及B体外平均溶出时间分别为42.25min及15.77min(P<0.001)。体内研究表明A及B水杨酸的C_max,T_p,AUC之间均无显著性差异(P>0.1)(A,B的服用量分别为4.5g及3.6g),B的相对生物利用度为125.59%。     

中国辽宁栽培西洋参化学成分的研究

中国辽宁栽培西洋参(Panax quinquefolius Linn)的总皂甙用低压硅胶柱和反相Rp18Labar柱层析分离得到18种化合物,用IR,MS(FD-MS,FAB-MS),¹³C-NMR及化学方法鉴定了16种化合物的化学结构;分别为棕榈酸(1),齐墩果酸(2),胡萝卜甙(daucosterin 3),人参皂甙-Rh₁(4),—Rg₃(5),—Rg₂(6),—Rg₁(7),—Rf(8),—Re(9),—Rd(10),—Rb₂(11),—Rb₁(12)、—R₀(13),蔗糖(14),人参三糖(15)及一种新皂甙(16),结构为:20(s)原人参二醇-3-[-O-β-D-吡喃糖基(1→2)β-D-葡萄吡喃糖基(1→2)β-D-葡萄吡喃糖基],20-[-O-β-D-葡萄吡喃糖基(1→6)β-D-葡萄吡喃糖甙,命名为人参皂甙-RAO(ginsenoside-RA₀)。化合物(4)和(5)系首次从西洋参中分离出的已知皂甙。     

甘氨双唑钠在大鼠和小鼠体内药代动力学

目的　观察甘氨双唑钠(CMNa)在动物体内的药代动力学。方法　采用HPLC方法测定生物样品中CMNa及其代谢物甲硝唑的含量。结果　小鼠体外转化试验表明血中90 min CMNa的转化率为91.8%,甲硝唑的生成率为67.3%。小鼠iv CMNa 57.3,171.9和515.7 mg.kg^-1后CMNa的T_{1/2T1/2β约为60 min。大鼠iv CMNa 171.9 mg.kg^-1后2 min及5 min CMNa及甲硝唑在组织含量较高;药后从尿中排泄的CMNa和甲硝唑分别占给药总量的8.4%和16.7%,从胆汁排泄分别占11.5%和5.1%,从粪排泄占0.14%和0.03%。CMNa平均血浆蛋白结合率为14.2%。结论　CMNa在体内迅速代谢为甲硝唑,原型药及代谢物的Cmax和AUC均与剂量正相关,二者主要经尿和胆汁排泄。}     

三七总皂苷油包水微乳的处方筛选及体内外评价

筛选口服油包水(W/O)微乳处方以提高三七总皂苷(panax notoginsenoside，PNS)中人参皂苷Rb₁的体内肠吸收，分别采用大鼠体内肠吸收、脂质体和平行人工膜(parallel artificial membrane permeability assay，PAMPA)等模型分别研究微乳的体内药代动力学及体外对膜流动性和药物膜转运性质的影响。主要以磷脂/乙醇(SP/EtOH)为表面活性剂，与PNS水溶液(400 mg·mL^-1)和不同油相分别制备11个W/O微乳处方。多数微乳处方可提高药物的大鼠体内肠吸收，其吸收促进作用除与所含表面活性剂有关外，不同油相的选用也会产生一定影响，其吸收促进作用大小为月桂酸甘油酯≈肉蔻豆酸异丙脂>棕榈酸异丙脂>棕榈酸异辛酯。长链(>C₁₄)脂肪酸酯的吸收促进作用低于中链脂肪酸酯(C₈~C₁₄)。多数微乳处方可不同程度的提高脂质体的膜流动性。PAMPA研究中，稀释后微乳(D-ME)中药物的有效透过系数(P_e)多数高于PNS对照溶液，表明微乳中的组分可以提高药物的膜透过能力，稀释前微乳(ME)的P_e与大鼠体内肠吸收具有相对较好的直线相关性(r=0.774 0)。W/O微乳可以促进人参皂苷Rb₁的肠吸收，吸收促进作用与其提高生物膜流动性有一定关系。PAMPA可以尝试引入制剂处方研究(如吸收促进剂等)的某些领域中。     

青蒿琥酯对人结肠腺癌细胞的放射增敏作用

目的 研究青蒿琥酯对人结肠腺癌SW480细胞的放射增敏作用。方法 用MTT法测定青蒿琥酯的半数抑制浓度(IC₅₀)。将SW480细胞分为4组：对照组、药物组(给予20% IC₅₀的青蒿琥酯)、照射组(给予6 MV 4 Gy X射线照射)、联合组(经20% IC₅₀浓度的青蒿琥酯培养8 h后,给予6 MV 4 Gy X射线照射)。MTT法测定4组细胞增殖抑制率。再测定细胞集落形成情况,计算细胞集落形成率(PE),细胞存活分数(SF)。根据多靶单击公式,计算平均致死剂量、外推值、2 Gy时的细胞存活分数和放射增敏比。用流式细胞仪测定各组细胞的凋亡率。结果 青蒿琥酯的IC50为20.87 μg·mL^-1。与对照组相比,3个实验组的细胞增殖抑制率和凋亡率有显著差异(P<0.05),而与其他3组相比,联合组的细胞增殖抑制率和凋亡率有显著差异(P<0.05)。放射增敏比为1.38。结论 青蒿琥酯对人结肠癌腺癌SW480细胞有一定的放射增敏作用,机制可能与促进凋亡有关。     

片剂释放度研究——四种测定方法的比较

本实验收集了国内阿司匹林生产样品五种及原料一种,作为典型药品进行了四种方法(杯法,崩解仪法,转篮法及循环法)的体外测定并测定了体内狗血药水平,将体内外测定结果进行了统计分析。以T₅₀%(中位数时间),T_d(特征时间63.2%)及m(斜率)三个参数和体内的T_max(高峰时间),C_max(高峰浓度)及血药水平时间曲线下面积A_uc三个参数作F检验,认为在各方法之间有显著性差异,并且循环法的灵敏性较好,但变异系数以杯法最小,体内外有一定的相关。     

维拉帕米对映体在人体的药代动力学

目的： 考察维拉帕米(VPM)和去甲维拉帕米(NVPM)对映体的药代动力学特性。 方法： 8名汉族男性健康志愿者分别po外消旋VPM 80 mg和静滴5 mg,以三甲基-β-环糊精为手性选择剂,毛细管电泳法同时测定VPM和NVPM对映体的血浆浓度,用二房室开放模型拟合药-时曲线。结果： po VPM的R/S(AUC),R/S(CL)和R/S(C_max)比率分别为3.66±1.86,0.3±0.053和4.82±0.58;NVPM的R/S(C_max)和R/S(AUC)比率为2.58和2.36。iv VPM的R/S(AUC),R/S(CL)和R/S(C_max)比率分别为1.04±0.29,1.01±0.3和1.36±0.12。R-(+)-VPM和S-(-)-VPM的绝对生物利用度为30.3±19和9.8±5.9。结论： VPM有较大的对映体特异性首过代谢,选择优对映体S-(-)-VPM为监测对象有利于临床合理使用外消旋VPM。     

麝香酮在大鼠、家兔和狗体内的药代动力学

麝香酮在大鼠体内的药时过程符合二室开放模型,在家兔和狗体内的药时过程则符合三室开放模型。大鼠、家兔和狗之间的药代动力学过程存在着显著的种属差异,大鼠iv麝香酮12,18和24 mg/kg三种剂量间的药代动力学主要参数无显著性差异。iv给药大鼠的T_1/2B为118.1～131.2min。家兔和狗的T_1/2B分别为24.9和30.0 min,T_1/2γ分别为331.9和366.4 min。大鼠、家兔和狗三b种动物的V_ss分别为23.0,51.7和7.3 L/kg.V_c分别为2.33,2.13和0.38 L/kg。     

Low glutathione<Emphasis Type="Italic"> S</Emphasis>-transferase dogs

Liver and kidney glutathione S-transferase (GST) activities to 1,2-dichloro-4-nitrobenzene (DCNB) as a substrate (GST-D activities) were measured in 280 dogs from five different breeders, and significant individual differences in this activity were observed in both organs. Interestingly, 34 out of the 280 dogs (i.e. 12.1%) were those in which liver GST-D activities were less than 10 nmol/min per mg cytosolic protein, low GST dogs, and the other dogs were classified as middle and high GST dogs for which the liver GST-D activities were 10–80 and >80 nmol/min per mg protein, respectively, and occurred at similar percentages (41.4% for the middle GST dog and 46.4% for the high GST dog). Furthermore, the existence of the low GST dogs was not limited to one particular breeder. There was a good correlation (r=0.910) between the liver and kidney GST-D activities, showing low activity in not only the liver but also the kidney in the low GST dogs. Although liver GST activity to 1-chloro-2,4-dinitrobenzene as a substrate (GST-C activity), catalyzed by various GST isozymes in dogs, was significantly correlated with liver GST-D activity, GST-C activity showed more than 450 nmol/min per mg protein even in the low GST dogs. There was no significant difference in cytochrome P450 content, 7-ethoxycoumarin O-deethylase activity or UDP-glucuronosyltransferase activity to p-nitrophenol as a substrate between low GST dogs and the other dogs. Finally, remarkably high plasma concentrations of DCNB were observed in the low GST dogs after single doses of DCNB at 5 or 100 mg/kg. The individual differences in GST-D activity are probably attributable to the content and/or activity of the theta class GST isozyme Yd_fYd_f since it has been reported that glutathione conjugation of DCNB is specifically catalyzed by GSTYd_fYd_f in dogs. In conclusion, we identified a number of low GST dogs in which the GST-D activities were not observed either in vivo or in vitro. The feasibility of using a single low dose of DCNB to phenotype dogs based on GST-D activity was confirmed. It was also suggested that low GST dogs have high susceptibility, including unexpected toxicity or abnormal exposure, to chemicals metabolized by GSTYd_fYd_f.     

川芎嗪对犬心脏血流动力学的作用

给麻醉犬静脉滴注川芎嗪1、2及4 mg/kg/min,连续10分钟;动物出现心率加快,心肌收缩力加强,血管扩张。这些作用随剂量的增加而加强。滴注1 mg/kg/min时,心率、LVP及dp/dt max增加,2 mg/kg/min时,心率、LVP、dp/dt max及冠脉血流明显增加。剂量增至4 mg/kg/min时,除上述指标明显增加外,还出现LVEDP、CI,心肌氧耗和脑血流增加,冠状动脉和脑血管阻力及总外周阻力降低。给清醒高血压犬滴注川芎嗪4 mg/kg/min及一次静注20'mg/kg也引起心率加速。心得安(ⅳ1～2 mg/kg)能对抗川芎嗪对麻醉和清醒犬的上述作用,而利血平则不能完全对抗川芎嗪的作用。     

青蒿素类似物的研究——Ⅰ、还原青蒿素的醚类、羧酸酯类及碳酸酯类衍生物的合成

青蒿素是当前治疗抗恶性疟疾的首选药物。为克服它的近期复燃率高的缺点,我们以还原青蒿素为中间体,在酸或碱的催化下与各种醇、羧酸酐或酰氯、氯甲酸酯反应,合成了它的醚类,羧酸酯类和碳酸酯类衍生物47个。经鼠疟(P.berghei)抗氯喹原虫株筛选,发现其中大多数化合物的抗疟效果超过青蒿素;以SD₉₀)作比较标准,超过青蒿素十倍左右的化合物有12个。     

Short-Chain Alkyl Esters of L-Dopa as Prodrugs for Rectal Absorption

The bioavailability of L-dopa following rectal administration of a series of short-chain alkyl esters of L-dopa was determined in rats and dogs. The esters were stable (>360 min) to hydrolysis in physiological buffer. In vitro enzymatic hydrolysis of the esters in plasma was species dependent, with the hydrolytic rate being faster in rat plasma (t _1/2 < 5 min) than dog plasma (t _1/2 = 68–181 min) or human plasma (t _1/2= 96–238 min). In vivo hydrolysis in dogs, as indicated by the L-dopa plasma profile following intravenous administration of the esters, was very rapid (high extravascular esterase activity). Significant L-dopa bioavailability was observed in rats following rectal administration of the methyl (46%), ethyl (14%), isopropyl (48%), butyl (100%), and 4-hydroxybutyl (13%) esters of L-dopa (rectal L-dopa absorption, <5%). In dogs, significant L-dopa bioavailability was also observed for the methyl (28%), isopropyl (30%), butyl (32%), and 4-hydroxybutyl (34%) esters of L-dopa in the presence of carbidopa. The data indicate that these highly water-soluble (>600 mg/ml) esters of L-dopa are potential candidates for controlled-release rectal delivery systems designed to provide more constant plasma L-dopa levels.     

Comparison of the Rates of Disintegration,Gastric Emptying,and Drug Absorption Following Administration of a New and a Conventional Paracetamol Formulation,Using γ Scintigraphy

Purpose. To investigate the hypothesis that faster drug absorption from a new paracetamol formulation containing sodium bicarbonate compared to that from a conventional formulation results from a combination of enhanced gastric emptying and disintegration/dissolution. Methods. Each formulation was administered in both fasted and fed states to 12 healthy volunteers. Gastric emptying and disintegration times were assessed by scintigraphy, and serum paracetamol concentrations were determined by HPLC. Results. The mean time to complete disintegration of the new tablets was faster than that for conventional tablets in both fasted (10.2 min vs. 22.5 min) and fed (14.3 min vs. 46.4 min) states, although this difference was statistically significant in the fed state only (p = 0.0053). Mean gastric emptying times for the new tablets, as measured by t₅₀ and t₉₀, were also faster than those for conventional tablets in both fasted (t₅₀ = 22.4 min vs. 47.5 min, t₉₀ = 30.9 min vs. 64.1 min) and fed (t₅₀ = 76.9 min vs. 106.4 min, t₉₀ = 152.7 min vs. 155.5 min) states, although these differences were not statistically significant. Two subjects showed dramatically retarded gastric emptying of the new tablets in the fasted state: if these atypical data are excluded, the differences in both t₅₀ and t₉₀ in the fasted state are significant (p = 0.0110 and 0.0035, respectively). Rate of paracetamol absorption reflected the gastric emptying profiles as shown by significant correlation of emptying times with partial AUC. Conclusions. It would seem that a combination of faster disintegration and gastric emptying of the new tablets is responsible for the faster rate of absorption of paracetamol from PA compared to P observed in both this study and in previous studies. The differences in gastric emptying are more pronounced in the fasted state, and the differences in disintegration are more pronounced in the fed state.     

青蒿素及其两个活性衍生物在狗体内药代动力学的研究

给狗静脉注射青蒿酯6 mg/kg后,血药时程符合一房室模型,药代动力学参数T_1/2为0.45 h,Cl_T为0.2 L/kg·h,Vd为0.15 L/kg。肌内注射蒿甲醚油剂10 mg/kg或30 mg/kg,吸收较快,血药浓度达峰时间分别在给药后4.0或1.9 h,峰浓度分别为0.7和3.7μg/ml。峰后末相消除半衰期分别为4.0和6.5 h。按矩量法计算得MRT值分别为7.0和9.2 h。青蒿素肌内注射后2 h血药浓度达高峰,峰浓度为0.2μg/ml,末相消除半衰期为1.6 h,MRT值为3.3 h。口服或直肠给药。血中未测到青蒿素。     

Bioavailability studies with ciglitazone in beagles II. Effect of propantheline bromide and metoclopramide HCL on bioavailability of a tablet

Bioavailability studies in fasted dogs with ciglitazone (CGZ), an oral hypoglycemic agent, suggested that an absorption window could contribute to the poor oral availability of CGZ. If so, propantheline bromide (PPB) could increase the residence time of CGZ at absorption sites and increase its bioavailability. Using this rationale, a Latin square study was conducted with CGZ in fasted dogs (n = 10) using treatments of a single 125mg tablet with and without 1.2 mg kg⁻¹ i.m. PPB. PPB was given in a single dose 1 h prior to administration of CGZ. Plasma concentrations of CGZ were assayed by HPLC. PPB significantly increased the AUC of CGZ by a ratio of 1.2 : 1 (p < 0.01). PPB also increased T_max from 2–8 h (p<0.001), and appeared to produce first order absorption of CGZ. In a separate CGZ study using fasted dogs (n = 10), a single 125mg tablet was administered with and without i.v. metoclopramide HCI (MCP). A 10mg dose of MCP was given 15 min prior to dosing with CGZ and repeated 1 h after dosing. MCP increases GI motility and was expected to decrease residence time of CGZ. MCP had no effect on T_max, but significantly decreased AUC by 8 per cent (p = 0.05). MCP also reduced C_max by 16 per cent (p = 0.06). Taken as a whole, these data suggest that the effect of meals to increase bioavailability of CGZ could be mediated at least in part, through an increase in GI residence time.     

Pharmacokinetics and pharmacodynamics of midazolam in the enflurane-anesthetized dog

Midazolam (Mid) is widely used as an anesthetic adjunct. To test its anesthetic effect vs. concentration relationships, it is desirable to establish stable and predictable Mid concentrations in plasma (and brain). Therefore, the pharmacokinetics of Mid in the enflurane-anesthetized dog were determined, and the ability of Mid to reduce the enflurane concentration required for anesthesia was measured and correlated with the Mid concentration in plasma [MID]. Mongrel dogs (n=9) were anesthetized with enflurane and the enflurane EC₅₀ (MAC—the end-tidal concentration at which one-half the dogs respond to the noxious stimulation of clamping of the tail, and one-half do not) was determined. Group 1 (n=5) received Mid 2.5mgJkg iv over 60 sec. Plasma for determination of [MID] was collected and the enflurane EC₅₀ was determined repeatedly over the 7–8-hr period following injection. Based on the pharmacokinetic parameters determined for Group 1, dogs in Group 2 (n=4) received Mid as a continuous infusion of 21 kg^–1 min^–1 for 5hr accompanied by an initial loading dose (3 mg/kg infused over 20 min) designed to produce a stable [MID] of 1000 ng/ml in plasma. Enflurane MAC and [MID] were determined regularly during the infusion and for 6hr after discontinuation of the infusion. There were no important differences in the pharmacokinetic parameters determined for Group 1 vs. Group 2: t_1/2,z=98±5 vs. 95±10min (mean ±SEM); V=3.94±0.27 vs. 2.98±25 L/kg; Cl=28.5±3.1 vs. 22.3±1.1 ml kg^–1 min^–1,respectively. When administered as a continuous intravenous infusion (Group 2), [MID] remained stable at 949 ± 53 ng/ml for more than 5hr. The enflurane EC₅₀ was reduced by 55% and the reduction remained stable during the 5 hours of Mid infusion. After a single iv bolus dose or after discontinuation of the continuous infusion, the degree of enflurane EC₅₀ reduction diminished toward the control (i.e., enflurane alone) value as [MID] declined. Midazolam's pharmacokinetics and plasma concentration vs. effect relationships have been determined to be consistent under two different experimental conditions.     

Hydralazine Pharmacokinetics and Interaction with Food: An Evaluation of the Dog as an Animal Model

The intravenous and oral dose-dependent pharmacokinetics of hydralazine and the effect of concurrent administration of food with hydralazine in dogs were evaluated for comparison with published human data. Four dogs were given intravenous and oral doses of hydralazine at 0.25, 1.0, 2.5, and 4.0 mg/kg. In addition, the oral 2.5 mg/kg dose was given with a meal. Blood samples were collected at appropriate intervals and analyzed for hydralazine. Pharmacokinetic analysis showed that AUC_oral/ dose (5552 to 13218 mg-min/ml) and F (0.36 to 0.77) increased significantly with dose, indicating saturation of first-pass metabolism, as is seen in humans. Total-body clearance (70 ml/min/kg) and steady-state volume of distribution (9 L/kg) were similar to human values. The bioavailability of hydralazine in the dog was decreased by 63% when the dose was given with a meal, which is comparable to some human data. It was concluded that the dog may be a useful model in which to study mechanisms of the hydralazine-food interaction.