魔芋葡甘聚糖分子链形态及链参数研究魔芋葡甘聚糖分子链形态及链参数研究

目的研究魔芋葡甘聚糖分子链形态，测定分子链参数。方法采用光散射、凝胶渗透色谱及粘度法测定溶液行为；采用原子力显微镜及透射电镜直接观测分子形貌。结果魔芋葡甘聚糖重均分子量M_w、均方根旋转半径〈S₂〉^1/2以及第二维利系数A₂分别为1.04×10⁶, (105.0±0.9) nm,和 (-1.59±0.28)×10^-3 mol·mL·g^-2，多分散系数M_w/M_n为1.02，Mark-Houwink方程为［η］=5.96×10^-2M^0.73_w；分子链参数M_L=982.82 nm^-1,q=27.93 nm, d=0.74 nm,h=0.26 nm,L=1 054.11 nm。结论直接观察到的分子形貌和根据溶液行为的推测均说明，魔芋葡甘聚糖为伸展的有一定刚性的半屈曲性直链分子，不存在支链。     

2-(3,4-二甲氧基苯基)-4-氧代-4H-色烯-3-基乙酸酯的晶体结构及旋光性

目的 探讨具有降血脂作用的黄酮醇衍生物2-（3,4-二甲氧基苯基）-4-氧代-4H-色烯-3-基乙酸酯（4）晶体结构及旋光性。方法 采用X射线单晶衍射技术获得绝对构型及SGW^®-1自动旋光仪测定化合物旋光性。结果 X射线单晶衍射表明化合物4属于正交晶系,P2₁2₁2₁空间群,晶胞参数a=7.763（2）Å,b=13.930（4）Å,c=14.906（4）Å,α=β=γ=90.00°,V=1 611.91（8）ų,Z=8;该晶态下分子间不存在氢键联系,分子以范德华力维系其在空间的稳定排列。从单晶数据可以看出,化合物4中二甲氧基取代的苯环相对于4H-色烯骨架有33.9（2）°扭转,推测可能存在旋光性;进一步的旋光实验结果证明该化合物具有左旋光性,比旋光度为[α]_D^19.1=-5.077°。结论 从单晶结果可知,由于化合物4中,二甲氧基取代的苯环相对于4H-色烯骨架有33.9（2）°扭转,形成手性,化合物具有旋光性。这类非黄酮苷类黄酮具有旋光性,未曾见报道。     

HPLC法测定那格列奈含量及有关物质

目的 建立那格列奈含量及有关物质的HPLC测定方法。方法 以C₁₈柱,磷酸盐缓冲液(pH 3.0)-乙腈(50∶50)为流动相,流量为1.0 ml·min^-1,柱温30℃,检测波长为210 nm。结果 在浓度为0.0601～1.8030μg范围线形关系良好,相关系数r=0.9993(n=6),重复性试验的RSD为0.9%(n=6)。有关物质分离较好。结论 本方法简单、准确,可作为那格列奈含量和有关物质的测定方法。     

何首乌有效成分二苯乙烯苷的药代动力学研究

目的建立小鼠和兔血浆中二苯乙烯苷浓度的HPLC测定方法,研究何首乌中二苯乙烯苷在小鼠和兔体内的药代动力学行为。方法用Diamonsil^TM C₁₈色谱柱(250 mm×4.6 mm,5 μm),以乙腈-甲醇-1%甲酸(15∶18∶67)为流动相,流速1.0 mL·min^-1,检测波长320 nm。结果线性范围为0.41～42.0 μg·mL^-1(γ=0.9999),最低检测浓度为0.051 μg·mL^-1。高、中、低3种不同浓度的平均回收率分别为97.98%,101.7%和104.5%,日内精密度RSD分别为8.7%,2.9%和5.5%。小鼠和兔iv二苯乙烯苷后药代动力学行为均符合二室模型,药代动力学参数分别为:T_1/2α=1.9,2.7 min;T_1/2β=8.3,13.5 min;K₂₁=6.6,4.2 h^-1;K₁₂=3.8,3.0 h^-1;K₁₀=16.0,11.2 h^-1;V_c=0.090,0.198 L·kg^-1;AUC=6.918,4.530 mg·h·L^-1;CL=1.445,2.208 L·h^-1·kg^-1。小鼠ig给药后二苯乙烯苷在胃肠道内的吸收不规则,且血药浓度很低,药代动力学行为不符合房室模型。结论建立了二苯乙烯苷血药浓度的HPLC测定方法,阐明了二苯乙烯苷的药代动力学特征。方法的专属性高,操作简便,结果准确。     

粉末X-射线衍射技术定量测定氨糖美辛肠溶片中吲哚美辛晶型γ的含量

目的 采用粉末X-射线衍射技术（powder X-ray diffraction,PXRD）对氨糖美辛肠溶片中吲哚美辛晶型γ的含量进行定量分析。方法 采用精细扫描方法,扫描范围9~12°,扫描速度5秒/步,步长0.02°。结果 氨糖美辛肠溶片中吲哚美辛晶型γ含量线性方程为y=13 728x+1 131（r=0.990 8）,检测限为21.2 mg·g^-1（S/N=4.6）。胶囊剂中晶型γ含量为45.73%~50.40%。结论 本法操作简单,在辅料没有干扰的情况下可用于氨糖美辛肠溶片中吲哚美辛晶型γ含量的定量分析和快速检测。     

谷胱甘肽在10-甲基吩噻嗪修饰碳糊电极上的电催化氧化及电分析方法

研究了谷胱甘肽(还原型, glutathione, GSH)在10-甲基吩噻嗪(10-methylphenothiazine, MPT)修饰碳糊电极(MPT/CPE)上的电催化氧化行为。GSH在裸碳糊电极(carbon paste electrode， CPE)上的直接电化学氧化过程十分迟缓， 但在MPT/CPE上于0.702 V处出现一个不可逆氧化峰， 氧化电流大幅度增大。计时电流(chronoamperometry， CA)实验测得该电催化氧化反应速率常数k为(5.44±0.03)×10² (mol·L^-1)^-1·s^-1。用线性扫描伏安法(linear sweep voltammetry, LSV)测得催化氧化峰电流与GSH在5.0×10^-6～2.0×10^-3 mol·L^-1呈良好的线性关系， 线性回归方程I_pa=3.536c+2.117， r=0.999 0， 检测限为1.0×10^-6 mol·L^-1。同时用本方法对含GSH的市售药品进行了含量测定， 结果可靠。     

厄贝沙坦多晶型X-射线粉末衍射定量分析

目的 建立厄贝沙坦晶型原料药的晶型含量分析方法，为药品晶型质量控制提供技术支撑。方法 采用X-射线粉末衍射法表征厄贝沙坦晶型A和晶型B。分别选取晶型A的特征衍射峰2θ=4.65°和晶型B的特征衍射峰2θ=7.99°的峰面积比值为定量参数，建立标准曲线检测晶型B的含量。结果 晶型B在晶型A和晶型B混合物中含量为2%~50%（质量分数）内线性关系良好（r=0.999 5），方法仪器精密度为4.7%，检测限浓度为1.12%（S/N=4.4）。结论 本研究建立的方法准确方便，可用于厄贝沙坦原料晶型A和晶型B混合物中晶型B的定量分析。     

RP-HPLC法测定注射用羟喜树碱脂质体含量

目的 建立测定注射用羟喜树碱脂质体含量的方法。方法 采用反相高效液相色谱法。色谱系统为ODS柱,以甲醇-水(60∶40)为流动相,检测波长为266 nm。结果 本品在5.886～10.930μg·ml^-1范围内呈线性关系,回归方程为:A=6.438×10⁴C-2.184×10⁴,r=0.9998。回收率为98.9%,RSD%为0.38(n=9)。结论 本法可测定注射用羟喜树碱脂质体中羟喜树碱的含量,方法快速、简便、准确。     

HPLC法测定妥布霉素滴眼液中5种抑菌剂

目的 建立同时测定妥布霉素滴眼液中5种抑菌剂(羟苯乙酯、硫柳汞、羟苯丙酯、苯扎溴铵和苯扎氯铵)的HPLC方法。方法 采用Agilent Zorbax SB-C₁₈ (4.6 mm×150 mm,5 μm)色谱柱,流动相A为1%三乙胺（磷酸调节pH值至3.5±0.05）;流动相B为甲醇,梯度洗脱,流速为1.0 mL·min^-1,柱温35 ℃,检测波长为214 nm。结果 羟苯乙酯、硫柳汞、羟苯丙酯、苯扎溴铵/苯扎氯铵各峰均分离良好;羟苯乙酯在0.77～192.5 μg·mL-1范围内线性关系良好(r=0.999 5),平均回收率为100.0%(RSD=0.9%,n=9);硫柳汞在2.16～541.0 μg·mL^-1范围内线性关系良好(r=0.999 7),平均回收率为100.1%(RSD=0.6%,n=9);羟苯丙酯在0.84～209.8 μg·mL^-1范围内线性关系良好(r=1.000 0),平均回收率为100.3%(RSD=1.0%,n=9);苯扎溴铵在4.36～1090 μg·mL^-1范围内线性关系良好(r=0.9992),平均回收率为100.2%(RSD=0.5%,n=9);苯扎氯铵（n-C12H25）3.22～805.0 μg·mL^-1范围内线性关系良好(r=0.999 8),平均回收率为100.1%(RSD=1.1%,n=9);苯扎氯铵（n-C14H29）1.66～413.9 μg·mL^-1范围内线性关系良好(r=1.000 0),平均回收率为100.1%(RSD=0.6%,n=9)。结论 该方法准确、灵敏、简便,可用于妥布霉素滴眼液中羟苯乙酯、硫柳汞、羟丙丙酯、苯扎溴铵及苯扎氯铵5种抑菌剂的检查。     

蛇床子素在兔体内药物代谢动力学

目的研究蛇床子素在兔体内的药物代谢动力学。方法用高效液相色谱法,以丹皮酚为内标,以甲醇-水(80∶20)为流动相,测定兔血液中蛇床子素(iv,10 mg·kg^-1)的含量。采用3P87程序计算药物代谢动力学参数。结果蛇床子素iv药代动力学符合二房室开放模型,T_1/2α=5.81 min,T_1/2β=42.2 min,K21=0.036 0·min^-1,K₁₂=0.045 0·min^-1,K₁₀=0.054 0·min^-1,AUC=235 mg·min·L^-1,CLs=0.043 0 L·min^-1·kg^-1,V_C=0.780 L·kg^-1。结论蛇床子素在兔体内分布及消除较快     

抗糖尿病药物那格列奈的合成

以异丙苯为原料，经付－克反应，卤仿反应，催化氢化反应得到反－4－异丙基环己烷甲酸，在二环己基碳二亚胺作用下，与N－羟基邻苯二甲酰亚胺反应得到活性酯，与D－苯丙氨酸乙酯发生酰化反应，水解后即得到那格列奈B晶型，再经过转晶得到那格列奈H晶型，反应总收率为9．8％。     

Effect of SLCO1B1 genetic polymorphism on the pharmacokinetics of nateglinide

AIMS: Nateglinide is a meglitinide analogue with antidiabetic action. A recent study showed that SLCO1B1 (which codes the OATP1B1 gene, also known as OATP-C, OATP2) is a major determinant which markedly affects the pharmacokinetics of repaglinide. Our objective was to assess the association between single nucleotide polymorphisms (SNPs) of SLCO1B1 and the pharmacokinetics of nateglinide. METHODS: Seventeen healthy volunteers with different SLCO1B1 genotypes (11 with 521TT, four with 521TC and two with 521CC) were enrolled in this study. Each was given a single oral dose of 90 mg nateglinide. Plasma concentrations of nateglinide were measured up to 8 h by HPLC. RESULTS: The C(max) and AUC(0,infinity) of nateglinide were 83% (P = 0.002) and 82% (P = 0.001) higher in the SLCO1B1521TC subjects (n = 4), and 76% (P = 0.016) and 108% (P = 0.001) higher in the SLCO1B1521CC subjects (n = 2) than in the SLCO1B1521TT subjects (n = 11), respectively. The t(1/2) of nateglinide in SLCO1B1521CC subjects was 78% longer than that in 521TT subjects (P = 0.036). The difference in t(max) values among the three genotypic groups was not statistically significant. CONCLUSIONS: Our results suggest that OATP1B1-mediated hepatic uptake of nateglinide may be the prior step for its metabolism and elimination. SLCO1B1521T > C SNP might play an important role in the pharmacokinetics of nateglinide.     

Stereoselective binding of chiral anti-diabetic drug nateglinide to plasma proteins

The binding of nateglinide (NA) enantiomers with human plasma (HP), human serum albumin (HSA) and bovine serum albumin (BSA) was investigated. The protein binding was studied over a drug concentration range of 5-100 μM at a protein concentration of 600 μM. Unbound drug concentrations were determined by direct chiral liquid chromatography using chiralcel OJ-RH column. At therapeutic drug concentrations, the protein binding of each enantiomer was >98%. The results showed that the binding of NA enantiomers was stereoselective, mutually competitive and non-linear. The binding characteristics were, however, opposite for the two most important plasma binding proteins. Opposite stereo-selectivity was observed between BSA and HSA while stereo-selectivity was identical between HSA and HP. Scatchard analysis was used to illustrate the different binding affinities of NA enantiomers to BSA, HSA and HP. The interaction between enantiomers observed in HP and serum albumins was confirmed as a competitive type interaction at the high affinity site. Scatchard analysis was used to illustrate the different binding affinities of NA enantiomers to BSA, HSA and HP.     

Different effects of SLCO1B1 polymorphism on the pharmacokinetics and pharmacodynamics of repaglinide and nateglinide

Thirty-two healthy volunteers with different SLCO1B1 genotypes ingested a 0.5-mg dose of repaglinide and 60-mg dose of nateglinide with a washout period of 1 week. Participants with SLCO1B1 c.521CC genotype (n = 4) had a 59% (P = 0.001) or 72% (P < 0.001) greater mean area under the plasma repaglinide concentration-time curve (AUC(0-infinity)) than participants with c.521TC (n = 12) or c.521TT (n = 16) genotypes. The AUC(0-infinity) of repaglinide metabolites M2 and M4 were 112% (P = 0.004) and 81% (P = 0.002) larger in participants with c.521CC genotype than in those with c.521TT genotype, but no differences existed in the pharmacokinetics of M1. Maximum decrease in blood glucose concentration correlated with repaglinide AUC(0-infinity) (r = 0.412, P = 0.019). SLCO1B1 polymorphism had no significant effect on the pharmacokinetics or pharmacodynamics of nateglinide or its M7 metabolite. Thus, in contrast to repaglinide, the disposition of nateglinide is unaffected by the SLCO1B1 c.521T>C polymorphism.     

那格列奈的合成

目的：合成抗2型糖尿病药物那格列奈。方法：以对异丙基苯甲醛为原料，经氧化、催化氢化、在高温高压碱性条件下，将顺式-对异丙基环己甲酸异构化为反式-异构体，然后与D-苯丙氨酸甲酯盐酸盐缩合、水解，合成那格列奈。结果：反应中间体以及目标产物的化学结构均经过了光谱分析确证，反应总收率为28．7％。结论：本方法步骤简单，易于工业化生产。     

那格列奈片的高效液相色谱分析

目的:建立那格列奈片中主药那格列奈及杂质的高效液相色谱测定方法。方法:采用Shim-Pack CLC-ODS(150mm×6.0mm)色谱柱,甲醇-0.02mol.L~(-1)磷酸盐缓冲液(pH6.6)(75:25)作流动相,检测波长210nm,含量测定采用外标法, 杂质检查采用面积归一化法。考察了不同流动相下那格列奈的色谱行为及其与杂质的分离情况。结果:在优化的色谱条件下,片剂辅料不干扰测定,有关杂质与主药那格列奈分离良好,那格列奈线性范围5.1～101.0 mg·L~(-1),最低检测限0.2 mg·L~(-1),含量测定的回收率99.4％～100.4％,RSD<1.7％。结论:此法简便,准确,专属性强,重现性好,可用于那格列奈片的质量控制、稳定性考察和有效期预测。     

那格列奈片的稳定性研究

目的:建立那格列奈片的稳定性分析方法,研究那格列奈片的稳定性。方法:采用HPLC法;色谱柱为ZY1104型YWG-C_(18)为(250mm×4.6mm,10μm);流动相:乙腈—[醋酸—醋酸钠缓冲液(pH3.6)]—甲醇(2:2:1);紫外检测波长258nm;流速1.0mL·min~(-1);内标法室温测定。结果:那格列奈在0.1～0.8mg·mL~(-1)范围内线性关系良好(r=0.9999);回收率为(100.05±0.88)％。结论:该稳定性分析方法操作简便,结果准确可靠,可排除分解产物的干扰。本片对湿、热及光均稳定,加速试验3个月其含量基本不变。     

I. Technological approaches to improve the dissolution behavior of nateglinide,a lipophilic insoluble drug: Nanoparticles and co-mixing

Nateglinide is a non-sulphonylurea insulinotropic oral antidiabetic agent. The main problem in formulating an oral dosage form is its low solubility in aqueous media. This problem is particularly critical for an anti-diabetic drug because it should be administered just before the meals and be quickly bioavailable to cover the post-prandial glycemic peak. In this work, some technological approaches have been studied to improve the dissolution rate of nateglinide. Furthermore, two different polymorphs of nateglinide (H and B) have been tested to evaluate the influence of the crystal habitus on the dissolution behavior of the drug. The results have clearly demonstrated that wettability plays a key role in the dissolution behavior of nateglinide. As a matter of fact the physical dispersion of the drug with colloidal silica or hydrophilic swellable polymers strongly enhances the dissolution rate of nateglinide. The two polymorphs tested did not show significant differences in terms of dissolution behavior.     

II. Technological approaches to improve the dissolution behavior of nateglinide,a lipophilic insoluble drug: Co-milling

Nateglinide is an oral antidiabetic agent that should be administered 10–30 min before the meal, but it shows low and pH-dependent solubility that may reduce its oral bioavailability.