Circular dichroism detection in high-performance liquid chromatography: Evaluation of the anisotropy factor

The application of a circular dichroism (c.d.) detection system in HPLC using a chiral stationary phase is presented. The simultaneous measurement of the absorbance and c.d. signal allows the evaluation of the anisotropy factor (g = Δ/) and thus the determination of the enantiomeric excess (e.e.) of the eluates. When this detection system is used in preparative chiral chromatography the collection of the enantiomeric fractions can be readily optimized.     

D1 Dopamine receptor-mediated substance P depletion in the striatonigral neurons of rats subjected to neonatal dopaminergic denervation: implications for self-injurious behavior

The present study examined the influences of dopamine (DA) receptor stimulation on enkephalin (Met5-enkephalin; ME) and tachykinin (substance P; SP) systems of basal ganglia of Sprague-Dawley rats, lesioned as neonates with 6-hydroxydopamine (6-OHDA). It has been proposed that the neonatal 6-OHDA-lesioned rat could serve as a model for the DA deficiency and self-injurious behavior (SIB) observed in the childhood neurological disorder. Lesch-Nyhan syndrome. In agreement with earlier work, the present study found that the neonatal 6-OHDA treatment at 3 days of age, reduced DA and caused an increase in ME and a decrease in SP content in the striatum and substantia nigra, when tested as adults. Administration of the DA precursor, L-dihydroxyphenylalanine (L-DOPA), to lesioned animals, induced SIB; increased DA and DOPAC levels; produced a greater decrease (-64%) in SP levels in the striatum and substantia nigra than was observed with lesion alone (-28%). The L-DOPA-induced decrease in SP levels and the SIB observed in the lesioned animals were blocked by pretreatment with the D1 receptor antagonist, SCH-23390. Moreover, administration of the D1 receptor agonist, SKF-38393, but not the D2 agonist, LY-171555, to lesioned animals mimicked the L-DOPA responses in all respects, except that the agonists did not alter DA or DOPAC levels. None of the DA agonists or antagonists treatments affected lesion-induced increase in ME levels in the striatum. These results indicate for the first time, that SIB precipitated by DA agonists in neonatal dopaminergic denervated animals, is associated with a marked and selective decrease in SP in the striatonigral SP neurons. This process has two components: (a) a retarded development of the SP system due to neonatal dopaminergic denervation: and (b) a depletion of the remaining SP, presumably by enhanced release due to D1 DA receptor-mediated activation of striatonigral SP neurons.     

Depressed levels of circulating menaquinones in patients with osteoporotic fractures of the spine and femoral neck

Vitamin K₁ functions in the conversion of glutamate residues, present in certain bone peptides, into the putatively active γ-carboxyglutamate form. We have shown previously that the circulating levels of vitamin K₁ are depressed in osteoporotic patients. However, it is known that menaquinones (vitamin K₂:MK) may be more effective than vitamin K₁ in this conversion of the inactive to active form of glutamate residues. A procedure for measuring such menaquinones has now demonstrated a marked deficiency of MK-7 and MK-8 in patients with osteoporotic fractures. It is suggested that estimates of circulating levels of K₁, MK-7, and MK-8 might provide a biochemical risk marker of osteoporotic fractures.     

大鼠脑组织单胺类递质及其代谢产物的检测方法研究

目的 :研究大鼠脑组织中单胺类递质及其代谢产物的高效液相反相离子对色谱测定法。方法 :采用LiChrosorbC18,10 μm色谱柱 ,流动相为甲醇 :水 (4 0 :60 ) ,含 0 .0 2 8g LEDTANa2 ,0 .15g LSDS ,0 .2ml LH2 SO4(pH 2 .5～ 3 ) ,荧光检测波长 :λEX=2 85 ,λEM=3 3 3。结果 :对 87只大鼠脑组织中 4种单胺类递质及其代谢产物的含量进行了同时测定 ,高香草酸 (HVA) 2 .5 0～ 40 .0 μg ml、去甲肾上腺素 (NE) 0 .0 1～ 0 .5 0 μg ml、多巴胺 (DA)0 .0 5～ 1.0 0 μg ml、5 羟色胺 (5 HT) 0 .0 2 5～ 0 .5 0 μg ml,峰面积与其含量呈良好的线性关系。 结论 :该法操作简便、快速、准确 ,为组织中单胺类递质及其代谢产物检测的一种理想方法 ,并适用于临床相关研究。     

顶空气相色谱法检测石茶感冒胶囊中的有机溶剂残留

目的建立石茶感冒胶囊中可能残留的7种有机溶剂（正己烷、苯、甲苯、对二甲苯、邻二甲苯、苯乙烯、二乙烯苯）的检测方法。方法采用顶空气相色谱法，色谱柱为Agilent HP—INNOWAX毛细管柱（30m×1．0mm，0．53μm），载气为高纯氮气；项空温度为70℃，顶空时间30min；柱温自30℃恒定5min，以10℃／min升温速率升至200℃，恒定5min；氢火焰离子检测器（FID），温度为250℃。结果7种有机溶剂残留物在所考察的浓度范围内线性关系良好（r=0．9994～0．9998），精密度RSD均小于5．0％，被测组分的平均回收率在99．16％～102．0％之间。结论该方法操作简便、快速、准确度高，可用于检测石茶感冒胶囊中的有机溶剂残留物。     

Comparison of assays for determination of peptide content for lyophilized thymalfasin*

Abstract: Precise determination of the peptide content in drug substance samples depends highly upon the particular peptide compound and methodology used. Four independent methods were evaluated and compared to determine which would produce the best experimental precision for analysis of thymalfasin (thymosin α‐1). Four different methods were evaluated including elemental analysis (CHN), quantitative amino acid analysis (AAA), high‐performance liquid chromatography (HPLC), and Kjeldahl. This study demonstrates that the AAA method is highly variable in one laboratory while quite precise in another laboratory. Similarly, HPLC results depended on the laboratory conducting the study with more precise values obtained under cGMP. On the contrary, the CHN method yielded highly precise [i.e. <2% coefficient of variation (CV)] values. As precise knowledge of protein content is fundamental for the compounding of final pharmaceutical product of a specific potency, the CHN analysis is recommended for peptide content determination of the drug substance thymalfasin.     

HPLC法测定滑膜炎颗粒中原儿茶醛的含量

目的建立滑膜炎颗粒剂中原儿茶醛的含量测定方法质量。方法采用高效液相色谱法对方中原儿茶醛进行含量测定。结果高效液相色谱法测定结果表明原儿茶醛在0．1005～1．005μg范围内呈线性关系，平均加样回收率为99．22％；RSD为0．72％。结论本法简便，重现性好、结果可靠，可作为控制滑膜炎颗粒剂的质量方法。     

236例无痛人工流产术的疗效观察

目的:探讨异丙酚和芬太尼混合液静脉麻醉、笑气吸入麻醉及2%利多卡因宫颈局部浸润麻醉三种镇痛方法在人工流产手术中的疗效比较。方法:自2003年8月至2004年1月对236例妇科门诊早孕要求终止妊娠的妇女实施无痛人工流产术。随机分成3组。A组:异丙酚+芬太尼静脉麻醉(85例);B组:N2O(笑气)吸入麻醉(88例);C组:2%利多卡因宫颈局部浸润麻醉(63例),观察人流术中其镇痛效果并对疼痛进行分级。结果:A组85例100%可达到完全不痛(疼痛分级为0级);B组65.90%可达到完全不痛,Ⅰ级23.86%,Ⅱ级9.09%,Ⅲ级1.15%;C组0例可达到完全不痛,Ⅰ级63.49%,Ⅱ级30.16%,Ⅲ级6.35%。结论:受术者如无心肺疾患及人流禁忌证,无痛人工流产术应选择异丙酚+芬太尼静脉麻醉可达到完全无痛,痛苦最小。     

丹参营养器官中脂溶性成分的动态变化规律

目的 测定丹参营养器官中丹参酮Ⅰ和丹参酮Ⅱ_A的含量,并揭示丹参生长过程中,丹参酮Ⅰ和丹参酮Ⅱ_A的动态变化规律.方法 采用反相高效液相色谱法,以Zorbax SB-C_(18)(150mm×4.6mm, 5.0μm)为色谱柱;甲醇-0.4%磷酸为流动相,梯度洗脱,流速为1.0 ml/min;二极管阵列检测器:检测波长分别为246, 270 nm;柱温为30℃.结果 丹参叶和茎中均未检出丹参酮Ⅰ和丹参酮Ⅱ_A,根中丹参酮Ⅱ_A和丹参酮Ⅰ的含量变化呈"单峰"曲线,丹参酮Ⅱ_A的含量在7月份最高,为2.94%,丹参酮Ⅰ含量在5月份最高,为0.78%.结论 4月至7月是丹参根中丹参酮积累的关键时期.     

Quantitative analysis of urinary glycine conjugates by high performance liquid chromatography: excretion of hippuric acid and methylhippuric acids in the urine of subjects exposed to vapours of toluene and xylenes

Summary A new method for the direct determination of hippuric acid (HA) and o-, m- and p-methylhippuric acids (MHAs) in the urine, metabolites of toluene and o-, m- and p-xylenes by high performance liquid chromatography (HPLC) is described. A stainless-steel column packed with silica gel having dinitrophenyl residue and a mixed solution of methanol/water/acetic acid (80/20/0.2) containing tetra-n-butylammonium bromide (0.2% w/v) as mobile phase was used. Concentrations of HA and MHAs were estimated from their peak height at a wave length of 225 nm. Urine can be analyzed directly without solvent extraction or pretreatment to obtain complete separation of HA and o-, m- and p-MHAs. Urine samples from male workers exposed to toluene or xylenes were analyzed for HA or MHAs. The urinary levels of HA and MHAs increased by exposure to toluene and xylenes in proportion to the environmental concentrations of the solvents, although there is a considerable variation in metabolite concentrations. The slope of regression line between toluene and HA and that between m-xylene and m-MHA were similar. The urinary concentrations of HA and MHAs corresponding to 100 ppm (TLV) of toluene was 2.35 g/g creatinine and that of m-MHA corresponding to 100 ppm (TLV) of m-xylene was 2.05 g/g creatinine. The warning levels of the urinary metabolite concentrations of a group of workers and that of an individual worker corresponding to TLV of organic solvent concentration is discussed.