N端为含氮杂环的新型羟乙基胺类BACE1抑制剂的设计、合成与活性评价

目的 开发一类N端含氮杂环结构的新型羟乙基胺（hydroxyethylamine,HEA）类BACE1抑制剂,筛选对抑制活性有贡献的新型N端结构。方法 设计并合成了8个N端为含氮杂环的HEA类化合物并鉴定其结构,同时,以儿茶酚类化合物（－）-表没食子儿茶素没食子酸酯（EGCG）作为阳性对照,分别测定它们对BACE1的抑制活性。结果 所有化合物均通过核磁共振氢谱和质谱确证其结构。BACE1抑制活性评价结果表明,其中N端为吲哚结构的化合物Ⅰ₆表现出明显的抑制活性。结论 含取代基的吲哚结构与BACE1的S2口袋具有一定的相互作用,有利于提高这类化合物对BACE1的抑制活性,可作为进一步研究的先导结构。     

丹参酮ⅡA自微乳制剂在大鼠体内血药浓度测定

目的 建立大鼠血浆中丹参酮ⅡA浓度的测定方法，考察丹参酮ⅡA自微乳制剂的药动学特征。方法 采用乙腈沉淀蛋白进行血浆预处理，以HPLC测定给药后大鼠血浆中丹参酮Ⅱ_A的浓度。色谱柱为Kromasil C₁₈柱(250 mm×4.6 mm，5.0 μm)，流动相为乙腈-0.01 mol·L^-1枸橼酸水溶液(80∶20)，流速1.0 mL·min^-1，检测波长：270 nm，柱温25 ℃。比较丹参酮Ⅱ_A自微乳制剂组和混悬液组大鼠血药浓度曲线的差异。结果 丹参酮Ⅱ_A在0.102~8.2 mg·L^-1内线性关系良好(r=0.998 6)，绝对回收率为77.5%~85.6%，相对回收率为88.3%~96.8%，日内和日间精密度RSD均小于15%。丹参酮Ⅱ_A自微乳制剂比丹参酮Ⅱ_A混悬液的AUC值高约2.5倍。结论 本法可以准确、灵敏地测定大鼠血浆中丹参酮Ⅱ_A的浓度。将丹参酮Ⅱ_A制成自微乳制剂，能提高其生物利用度。     

LC-MS/MS测定人血浆中哌甲酯

目的 建立LC-MS/MS测定人血浆中盐酸哌甲酯的浓度。方法 待测血浆1.0 mL，经1 mol·L^-1的氢氧化钠40 μL碱化后，用4 mL乙醚萃取处理，采用Eclipse XDB-C₁₈ (4.6 mm×150 mm，5 μm)色谱柱，以甲醇和水为流动相梯度洗脱，流速1.0 mL·min^-1。以电喷雾正离子源离子化，检测离子对盐酸哌甲酯为234.0/84.0，内标卡马西平为237.0/194.0。结果 血浆中内源性物质对测定无干扰，最低定量限为0.1 ng·mL^-1，在1~100 ng·mL^-1内盐酸哌甲酯线性关系良好(r=0.999 1)，日内、日间RSD均小于8%，样品分析时间为10 min。结论 该法专属性强、灵敏度高，操作简便快速，测定结果可靠，适于进行盐酸哌甲酯血药浓度监测。     

大麻Ⅰ型受体抑制剂研究进展

临床试验表明，大麻Ⅰ型受体(CB₁)抑制剂利莫那班(rimonabant)在治疗肥胖和戒烟方面具有良好效果^［1］,CB₁受体抑制剂还具有治疗药物成瘾、认知和记忆紊乱、神经错乱等疾病的潜力。CB₁受体抑制剂与诸多疾病的相关性大大推进了新的CB₁受体抑制剂的发展。本文主要对各种CB₁受体抑制剂的结构及活性研究的最新进展进行综述。     

改良RP-HPLC测定全血中环孢素A的浓度

目的 建立一种简便的RP-HPLC法测定全血中环孢素A(CsA)的浓度,为临床合理应用CsA提供依据。方法 全血样品1 mL经乙醚提取,正己烷洗涤去干扰后,采用Zorbax SB-C₁₈ 柱 (4.6 mm×150 mm,3.5 μm) 分离,流动相为乙腈-甲醇-水-异丙醇(60∶10∶29∶1),流速1.5 mL·min^-1,柱温70 ℃,检测波长210 nm;环孢素D(CsD)为内标。结果 CsA全血浓度在25~1 600 ng·mL^-1内线性关系良好(r=0.999 8),平均方法回收率99.51%,日内、日间RSD均小于5%,最低检测限5 ng·mL^-1。结论 本法简便快速,灵敏度高,重复性好,线性范围广。用于患者全血中CsA浓度监测,效果良好。     

HPLC–MS/MS测定赖诺普利血药浓度及其在药动学研究中的应用

目的 建立HPLC-MS/MS测定人血浆中赖诺普利的浓度并研究其药动学特征,为该药的临床应用提供依据。方法 20名健康受试者单剂量口服赖诺普利片20 mg后,采用HPLC-MS/MS测定其血药浓度,利用DAS软件对血药浓度-时间数据进行药动学模型拟合和参数计算,应用AIC法判别房室模型。结果 血浆中赖诺普利在2.0~200 ng·mL^-1内线性关系良好(r=0.997 5),平均回收率为88.8%,日内RSD≤6.62%,日间RSD≤13.0%。最佳房室模型为单室模型(Wi=1/C2, AIC=4.61),主要药动学参数t_1/2为(10.91±3.71)h,t_max为(6.65±1.50)h,C_max为(98.15±23.66)ng·mL^-1,Ka为(0.83±1.28)h^-1,Vd/F为(220.70±62.82)L,AUC_0-72为(1 437.41±399.68)ng·h·mL^-1,AUC_0-∞为(1 516.54±376.83)ng·h·mL^-1。结论 该分析方法专属性强、灵敏度高,适合大样本分析,满足临床血药浓度监测的要求并适用于药动学领域的研究。     

HPLC测定烫伤合剂中盐酸小檗碱的含量

目的 建立烫伤合剂中盐酸小檗碱的含量测定方法。方法 色谱柱为Inertsil C_8-3柱(4.6 mm×250 mm,5 μm),流动相为0.05 mol·L^-1磷酸二氢钠溶液-乙腈-磷酸(70∶30∶0.08 );流速为1 mL·min^-1,柱温：35 ℃,检测波长为260 nm。结果 盐酸小檗碱在5.28~52.8 mg·L^-1内峰面积与浓度呈良好的线性关系,Y=2.45×10⁴X＋4.91×10³(r=0.999 4),平均回收率为100.30%,RSD为1.24% (n=6)。结论 方法简便、准确、重复性好,可作为控制产品质量的定量依据。     

复方氨酚曲马多片中对乙酰氨基酚的人体药代动力学研究

目的 研究氨酚曲马多片在中国健康人体内的药代动力学特性。方法 10名健康志愿者(男女各半)单剂量口服2片氨酚曲马多片（每片曲马多/对乙酰氨基酚为37.5 mg/325 mg）。对乙酰氨基酚血药及尿药浓度采用高效液相色谱-紫外（HPLC-UV）检测法测定。结果 受试者单次口服给药后,以HPLC-UV法测血浆及尿液中对乙酰氨基酚浓度。采用DAS软件计算对乙酰氨基酚的药代参数。C_max为(10.95±7.85)mg·L^-1,T_max为(0.83±0.29)h,t_1/2为(2.09±0.34)h,AUC_0～24为(26.93±11.64)mg·h·L^-1,AUC_0-∞为(27.74±11.57)mg·h·L^-1,尿液中24 h以原形排泄百分比(2.90±1.32)%;受试者各项检查未见异常,无不良反应发生。结论 对血浆药代动力学参数及尿中药物排泄量进行性别单因素方差分析,结果未显示性别差异。该药在试验剂量下具有良好的安全性。     

天麻素血药浓度测定及药动学研究

目的 建立天麻素血浆药物浓度LC-MS/MS测定法,测定健康受试者血浆中天麻素的浓度并评价天麻素胶囊的药动学。方法 建立以阿昔洛韦为内标的天麻素血药浓度LC-MS/MS测定方法,色谱柱为Atlantics T3(100 mm×3.0 mm,3 μm),流动相为乙腈-水(10∶90),对18名健康受试者单剂量口服150 mg天麻素胶囊进行药动学研究。结果 建立了简单、专属的天麻素血浆药物浓度的LC-MS/MS测定法,以沉淀法进行样品前处理,无杂质干扰测定,灵敏度达到了3.00 ng∙mL^-1,每个生物样品分析时间仅为2 min。18名健康受试者口服天麻素胶囊150 mg后,测定血浆样品并估算天麻素的药动学参数,T_max均值为(0.8±0.3)h,t_1/2均值为(2.1±0.4)h,C_max均值为(378±84)ng∙mL^-1,AUC_0-12 均值为(878±175)ng∙h∙mL^-1,AUC_0-∞均值为(897±175)ng∙h∙mL^-1。结论 本法快速、准确、灵敏度高且前处理简单,能很好的应用于药动学研究。     

HPLC测定人血浆中霉酚酸及其代谢物浓度

目的 建立反相高效液相色谱法,同时测定人血浆中霉酚酸(mycophenolic acid, MPA)、酚化葡萄糖醛麦考酚酸(phenol glucuronide metabolite, MPAG)、酰基化MPAG(acyl-MPAG, AcMPAG)的浓度。方法 用蛋白沉淀法对样品进行处理。固定相为Zorbax Eclipse XDB C₁₈柱(4.6 mm×250 mm,5 mm),流动相：甲醇: 20 mmol×L^-1 NaH₂PO₄(用20%磷酸调至pH 3.0)为55∶45,流速：1.2 mL×min^-1,检测波长：304 nm,柱温：45 ℃。结果 MPA、MPAG、AcMPAG浓度在0.2~50 mg×mL^-1(r=0.999 7)、2.8~531 mg×mL^-1(r=0.999 9)、0.3~24 mg×mL^-1( r=0.999 4)内呈良好的线性关系。MPA及其代谢物的绝对回收率均大于80%,MPA、MPAG、AcMPAG的相对回收率分别为94.0%~101.4%,98.4%~101.9%和96.1%~104.2%。日内及日间RSD远低于15%。结论 采用反相高效液相色谱法测定人血浆中MPA、MPAG、AcMPAG的浓度和进行药物代谢动力学研究,方法灵敏度高、重复性强     

外源性硫化氢对嗜铬细胞瘤细胞β位淀粉样前体蛋白裂解酶1表达的影响

 目的观察外源性硫化氢（H2S）对嗜铬细胞瘤细胞（PC12）茁位淀粉样前体蛋白裂解酶1（BACE1）表达的影响,并探讨可
能涉及的细胞信号机制。方法用不同浓度的硫氢化钠（NaHS）处理体外培养的PC12细胞,利用RT-PCR和Western blot法检
测细胞内BACE1mRNA及蛋白表达;继以LY294002 和PD98059 分别阻断磷脂酰肌醇3-激酶/丝氨酸苏氨酸蛋白激酶（PI3-K/
Akt）及丝裂酶原活化蛋白激酶/细胞外信号调节激酶1/2（MAPK/ERK1/2）通路,Western blot 法检测其对NaHS 诱导的通路下游
蛋白Akt1 和ERK1/2 磷酸化的影响及其对BACE1 蛋白表达变化的调节;ELISA法检测细胞培养液中A茁42 水平的变化。结果
NaHS 在实验浓度范围内呈剂量依赖性下调BACE1mRNA 及蛋白表达,200 μmol/L 时最明显,各NaHS 组与对照组相比,差异
均有统计学意义（ P<0.05）;LY294002 抑制NaHS 诱导的Akt1蛋白磷酸化,削弱NaHS 对BACE1 蛋白的下调作用,其表达在
LY294002 预处理组与NaHS 200 μmol/L组相比,差异具有统计学意义（ P<0.05）;而PD98059 虽能抑制NaHS 导致的ERK1/2
蛋白磷酸化,但对其调节BACE1 蛋白表达无影响,PD98059 预处理组与NaHS 200 μmol/L 组相比,差异无统计学意义（ 跃
0.05）;不同处理条件下的A茁42 表达与BACE1 变化趋势基本一致。结论外源性H2S 下调PC12 细胞BACE1 表达,其机制可
能与PI3-K/Akt 信号通路的激活有关,而与MAPK/ERK1/2 通路无关。     

磁共振弥散张量成像对轻度脊髓型颈椎病的诊断价值

目的探讨3.0T磁共振DTI技术对无信号改变脊髓型颈椎病的诊断价值。方法选择21例健康志愿者作为对照组和42例无T2信号改变的脊髓型颈椎病患者行颈髓DTI成像,根据患者有无颈椎病体征将其分为阴性体征组（A组）和阳性体征组（B组）。分析各组表观弥散系数(ADC)、分数各向异性值(FA)、平行于颈髓长轴、前后径和左右径本征值λ₁、λ₂、λ₃值的变化。结果所有受检者DTI成像显示满意。对照组颈髓平均ADC值为（0.78±0.08）×10^-3mm²/s,FA值为0.72±0.03,λ₁、λ₂、λ₃值分别为（1.51±0.15）×10^-3、（0.42±0.09）×10^-3、（0.41±0.10）×10^-3mm²/s。A组FA值大于B组（P＜0.01）,B组ADC、λ₁、λ₂、λ₃值均大于A组（P＜0.05）;对照组与A组比较,ADC、FA、λ₁值无统计学差异（P＞0.05）,A组λ₂、λ₃值大于对照组（P＜0.05）;对照组FA值大于B组（P＜0.01）,B组ADC、λ₂、λ₃值大于对照组（P＜0.05）,而对照组和患者组间λ₁值无统计学差异（P＞0.05）。结论ADC、FA、λ₁、λ₂、λ₃值是检测脊髓型颈椎病早期颈髓微结构改变的敏感指标。     

聚乙二醇化重组人粒细胞集落刺激因子的药代动力学与组织分布研究

目的 研究聚乙二醇化重组人粒细胞集落刺激因子(PEG-rhG-CSF)在动物体内的药代动力学与组织分布.方法 猕猴给予不同剂量(30、100和300μg/kg)的PEG-rhG-CSF,酶联免疫吸附法(ELISA)测定猕猴血浆中PEG-rhG-CSF浓度;[(125)I]标记示踪法结合分子排阻色潜法观察PEG-rhG-...     

积雪草中积雪草酸的分离、纯化及其含量测定

目的分离纯化积雪草中积雪草酸,并建立高效液相色谱法(high-performance liquid chromatography,HPLC)测定积雪草酸的含量。方法超声提取积雪草中积雪草酸,将粗提物用石油醚-丙酮体系在硅胶柱上梯度洗脱,HPLC法测定积雪草酸的含量。色谱条件:采用Waters Symmetry C18色谱柱(4.6 mm×250 mm,5μm),流动相为乙腈-10 mmol.L-1乙酸铵溶液(38∶62,V/V),检测波长为210 nm,流速为1.0 mL.min-1,柱温25℃,进样体积为20μL。结果积雪草酸在浓度10～200 mg.L-1线性关系良好(R2=0.999 5),其日内、日间RSD均小于5.4%,回收率为100.5%。积雪草中积雪草酸含量为0.99 g.kg-1。经提取、分离、纯化得到积雪草酸白色粉末,纯度为79.0%。结论本实验所用分析方法简便、准确、重复性好,可用于积雪草酸的含量测定;所用提取分离及纯化积雪草酸的方法可使中药中积雪草酸得到有效富集。     

液相色谱-串联质谱法测定阿德福韦及其前体化合物在大鼠血浆中的浓度

目的 建立测定大鼠血浆中阿德福韦（PMEA）及其前体药物APD2、PMEA-CA的液相色谱-串联质谱(LC-MS/MS)法。方法 分别采用不同的血浆样品处理方法和色谱条件测定PMEA及其前体化合物。测定PMEA时,血浆样品经甲醇沉淀蛋白后,用Discovery C₁₈柱分离,以甲醇-0.5％甲酸（20∶80,V/V）为流动相,9-(3-膦酸甲氧基丙基)腺嘌呤为内标,采用ESI源以多反应监测方式对血浆样品中的PMEA进行定量分析。测定APD2和PMEA-CA时,血浆样品经固相萃取后,用Hypersil ODS2柱分离,以甲醇-5 mmol·L^-1乙酸铵（70∶30,V/V）为流动相,格列本脲为内标,采用ESI源以多反应监测方式对血浆中APD2和PMEA-CA进行定量分析。结果 PMEA和PMEA-CA线性范围为25～5 000 μg·L^-1,ADP2的线性范围为10～2 500 μg·L^-1,日内、日间精密度均<5.5 %。结论 本方法专属性强、灵敏度高,适用于PMEA前体药APD2及PMEA-CA的临床前药代动力学研究。     

Relationship between fasting plasma glucose and glycosylated hemoglobin: potential for false-positive diagnoses of type 2 diabetes using new diagnostic criteria

Mayer B. Davidson, MD; David L. Schriger, MD, MPH; Anne L. Peters, MD; Brett Lorber, MPH

JAMA. 1999;281:1203-1210.

Context  New criteria for the diagnosis of type 2 diabetes mellitus have recently been introduced that lowered the diagnostic fasting plasma glucose (FPG) concentration from 7.8 to 7.0 mmol/L (140 to 126 mg/dL).

Objective  To determine if individuals with diabetes diagnosed by the new FPG concentration criterion would have excessive glycosylation (elevated hemoglobin [HbA_1c] levels).

Definitions  We determined the distribution of HbA_1c levels in individuals using 4 classifications: (1) normal by the new criterion (FPG concentration <6.1 mmol/L [110 mg/dL]); (2) impaired fasting glucose by the new criterion (FPG concentration of 6.1-6.9 mmol/L [110-125 mg/dL]); (3) diabetes diagnosed solely by the new FPG concentration criterion of 7.0 through 7.7 mmol/L (126-139 mg/dL); and (4) diabetes diagnosed by the previous FPG concentration criterion of 7.8 mmol/L (140 mg/dL) or higher.

Design  Cross-sectional analysis of 2 large data sets (NHANES III and Meta-Analysis Research Group [MRG] on the Diagnosis of Diabetes Using Glycated Hemoglobin) that contained individuals in whom FPG concentrations, 2-hour glucose concentrations using an oral glucose tolerance test, and an HbA_1c level were simultaneously measured. We cross-tabulated FPG concentrations (<6.1 mmol/L [110 mg/dL], 6.1-6.9 mmol/L [110-125 mg/dL], 7.0-7.7 mmol/L [126-139 mg/dL], and 7.8 mmol/L [140 mg/dL]) and HbA_1c levels separated into 3 intervals: normal, less than the upper limit of normal (ULN); slightly elevated, ULN to ULN plus 1%; and high, higher than ULN plus 1%.

Results  Among subjects with normal FPG concentrations, HbA_1clevels in the NHANES III (and the MRG) data sets were normal in 97.3% (96.2%), slightly elevated in 2.7% (3.6%), and high in 0.1% (0.2%). Among individuals with impaired fasting glucose, HbA_1c concentrations were normal in 86.7% (81.4%), slightly elevated in 13.1% (16.4%), and high in 0.2% (2.2%). Among diabetic patients diagnosed by the new FPG criterion only, HbA_1c levels were normal in 60.9% (59.6%), slightly elevated in 35.8% (32.8%), and high in 3.4% (7.6%). In diabetic patients diagnosed by the former FPG criterion, HbA_1c levels were normal in 18.6% (16.7%), slightly elevated in 32.5% (21.0%), and high in 48.9% (62.3%).

Conclusions  About 60% of the new cohort of diabetic patients in both data sets have normal HbA_1c levels. We believe that diabetes should not be diagnosed in those with FPG concentrations less than 7.8 mmol/L (140 mg/dL) unless excessive glycosylation is evident. Individuals without excessive glycosylation but with moderate elevations of FPG concentrations (6.1-7.7 mmol/L [110-139 mg/dL]) should be diagnosed as having impaired fasting glucose and treated with an appropriate diet and exercise. This diagnostic labeling achieves the goal of early intervention without subjecting these persons to the potentially negative insurance, employment, social, and psychological consequences of a diagnosis of diabetes mellitus.

     

Effect of calcium carbonate on the absorption of levothyroxine

Context  The effect of calcium carbonate on the absorption of levothyroxine has not been studied systematically. Such a potential drug interaction merits investigation because concurrent treatment with both drugs is common, particularly in postmenopausal women. Objective  To investigate the potential interference of calcium carbonate in the absorption of levothyroxine. Design  Prospective cohort study conducted from November 1998 to June 1999, supplemented with an in vitro study of thyroxine (T₄) binding to calcium carbonate. Setting  Veterans Affairs Medical Center in West Los Angeles, Calif. Patients  Twenty patients (age range, 27-78 years; n=11 men) with hypothyroidism who were taking a stable long-term regimen of levothyroxine were included in the study. All patients had serum free T₄ and thyrotropin values in the normal range before beginning the study. Intervention  Subjects were instructed to take 1200 mg/d of elemental calcium as calcium carbonate, ingested with their levothyroxine, for 3 months. Main Outcome Measures  Levels of free T₄, total T₄, total triiodothyronine (T₃), and thyrotropin, measured in all subjects at baseline (while taking levothyroxine alone), at 2 and 3 months (while taking calcium carbonate and levothyroxine), and 2 months after calcium carbonate discontinuation (while continuing to take levothyroxine). Results  Mean free T₄ and total T₄ levels were significantly reduced during the calcium period and increased after calcium discontinuation. Mean free T₄ levels were 17 pmol/L (1.3 ng/dL) at baseline, 15 pmol/L (1.2 ng/dL) during the calcium period, and 18 pmol/L (1.4 ng/dL) after calcium discontinuation (overall P<.001); mean total T₄ levels were 118 nmol/L (9.2 µg/dL) at baseline, 111 nmol/L (8.6 µg/dL) during the calcium period, and 120 nmol/L (9.3 µg/dL) after calcium discontinuation (overall P=.03). Mean thyrotropin levels increased significantly, from 1.6 mIU/L at baseline to 2.7 mIU/L during the calcium period, and decreased to 1.4 mIU/L after calcium discontinuation (P=.008). Twenty percent of patients had serum thyrotropin levels higher than the normal range during the calcium period; the highest observed level was 7.8 mIU/L. Mean T₃ levels did not change during the calcium period. The in vitro study of T₄ binding to calcium showed that adsorption of T₄ to calcium carbonate occurs at acidic pH levels. Conclusions  This study of 20 patients receiving long-term levothyroxine replacement therapy indicates that calcium carbonate reduces T₄ absorption and increases serum thyrotropin levels. Levothyroxine adsorbs to calcium carbonate in an acidic environment, which may reduce its bioavailability.      

Glycemic Control With Diet, Sulfonylurea, Metformin, or Insulin in Patients With Type 2 Diabetes Mellitus: Progressive Requirement for Multiple Therapies (UKPDS 49)

Context  Treatment with diet alone, insulin, sulfonylurea, or metformin is known to improve glycemia in patients with type 2 diabetes mellitus, but which treatment most frequently attains target fasting plasma glucose (FPG) concentration of less than 7.8 mmol/L (140 mg/dL) or glycosylated hemoglobin A_1c(HbA_1c) below 7% is unknown. Objective  To assess how often each therapy can achieve the glycemic control target levels set by the American Diabetes Association. Design  Randomized controlled trial conducted between 1977 and 1997. Patients were recruited between 1977 and 1991 and were followed up every 3 months for 3, 6, and 9 years after enrollment. Setting  Outpatient diabetes clinics in 15 UK hospitals. Patients  A total of 4075 patients newly diagnosed as having type 2 diabetes ranged in age between 25 and 65 years and had a median (interquartile range) FPG concentration of 11.5 (9.0-14.4) mmol/L [207 (162-259) mg/dL], HbA_1c levels of 9.1% (7.5%-10.7%), and a mean (SD) body mass index of 29 (6) kg/m². Interventions  After 3 months on a low-fat, high-carbohydrate, high-fiber diet, patients were randomized to therapy with diet alone, insulin, sulfonylurea, or metformin. Main Outcome Measures  Fasting plasma glucose and HbA_1c levels, and the proportion of patients who achieved target levels below 7% HbA_1c or less than 7.8 mmol/L (140 mg/dL) FPG at 3, 6, or 9 years following diagnosis. Results  The proportion of patients who maintained target glycemic levels declined markedly over 9 years of follow-up. After 9 years of monotherapy with diet, insulin, or sulfonylurea, 8%, 42%, and 24%, respectively, achieved FPG levels of less than 7.8 mmol/L (140 mg/dL) and 9%, 28%, and 24% achieved HbA_1c levels below 7%. In obese patients randomized to metformin, 18% attained FPG levels of less than 7.8 mmol/L (140 mg/dL) and 13% attained HbA_1c levels below 7%. Patients less likely to achieve target levels were younger, more obese, or more hyperglycemic than other patients. Conclusions  Each therapeutic agent, as monotherapy, increased 2- to 3-fold the proportion of patients who attained HbA_1c below 7% compared with diet alone. However, the progressive deterioration of diabetes control was such that after 3 years approximately 50% of patients could attain this goal with monotherapy, and by 9 years this declined to approximately 25%. The majority of patients need multiple therapies to attain these glycemic target levels in the longer term.