Discordant genotyping results using DNA isolated from anti‐doping control urine samples

The UGT2B17 gene deletion polymorphism is known to correlate to urinary concentration of testosterone‐glucuronide and hence this genotype exerts a large impact on the testosterone/epitestosterone (T/E) ratio, a biomarker for testosterone doping. The objective of this study was to assess if DNA isolated from athletes’ urine samples (n = 713) obtained in routine doping controls could be targeted for genotyping analysis for future integration in the athlete's passport. A control population (n = 21) including both urine and blood DNA was used for genotyping concordance test. Another aim was to study a large group (n = 596) of authentic elite athletes in respect of urinary steroid profile in relation to genetic variation. First we found that the genotype results when using urine‐derived DNA did not correlate sufficiently with the genotype obtained from whole blood DNA. Secondly we found males with one or two UGT2B17 alleles had higher T/E (mean 1.63 ± 0.93) than females (mean 1.28 ± 1.08), p˂0.001. Unexpectedly, we found that several male del/del athletes in power sports had a T/E ˃1. If men in power sport exert a different urinary steroid profile needs to be further investigated. The other polymorphisms investigated in the CYP17A1, UGT2B7 and UGT2B15 genes did not show any associations with testosterone and epitestosterone concentrations. Our results show that genotyping using urine samples according to our method is not useful in an anti‐doping setting. Instead, it is of importance for the anti‐doping test programs to include baseline values in the ABP to minimize any putative impact of genotype. Copyright © 2016 John Wiley & Sons, Ltd.     

Epidemiological investigation of the UGT2B17 polymorphism in doping control urine samples and its correlation to T/E ratios

The deletion polymorphism of the enzyme UGT2B17 is known to correlate with the level of the testosterone to epitestosterone (T/E) ratio in urine specimen. Due to the importance of the T/E ratio to detect testosterone abuse in doping analysis, a PCR‐ELISA system (Genotype® UGT test, AmplexDiagnostics) was established to identify the UGT2B17 phenotype in urine samples. Epidemiological investigations in a set of 674 routine doping controls (in‐ and out‐of‐competition) resulted in 22.8% homozygote gene‐deleted and 74.5% UGT2B17‐positive athletes. The validated test system has shown to be robust and sensitive: in only 18 cases (2.7%) isolation of cell material from urine failed. Following hydrolysis of glucuronidated conjugates, steroids were analyzed as bis‐TMS derivatives by gas chromatography‐mass spectrometry (GC‐MS), for example, testosterone (T) and epitestosterone (E). Additionally, isotope ration mass spectrometry (IRMS) analysis and luteinizing hormone (LH) measurement were applied. Mean T/E ratios significantly correlated with the UGT2B17 phenotype (del: T/E 0.9; pos: 1.7), however the values did not differ as distinctive as reported in previous studies. Additionally, the T/E ratios in the gene‐deleted group did not show a normal curve of distribution (median of T/E 0.5). Obviously, beside the UGT2B17 deletion further influences have to be taken into account, for example, polymorphisms or induction of other metabolizing enzymes. Our results indicate that the UGT2B17 polymorphism might be insufficient when utilized solely as a crucial parameter for individual interpretation of T/E in urine. Nevertheless, the detection of the UGT2B17‐gene deletion in urine samples would provide additional information important for gathering evidence in analysis of steroids in doping control. Copyright © 2011 John Wiley & Sons, Ltd.     

Determination of 13C/12C ratios of urinary excreted boldenone and its main metabolite 5β‐androst‐1‐en‐17β‐ol‐3‐one

Boldenone (androsta–1,4–dien–17β–ol–3–one, Bo) is an anabolic steroid known to have been used in cattle breeding or equine sport as a doping agent for many years. Although not clinically approved for human application, Bo or its main metabolite 5β‐androst‐1‐en‐17β‐ol‐3‐one (BM1) were detected in several doping control samples. For more than 15 years the possibility of endogenous Bo production in human beings has been discussed. This is a challenging issue for doping control laboratories as Bo belongs to the list of prohibited substances of the World Anti‐Doping Agency and therefore the chance for false positive testing is significant. By GC/C/IRMS (gas chromatography/combustion/isotope ratio mass spectrometry) it should be possible to analyze the ¹³C/¹²C ratio of either Bo or BM1 and to distinguish whether their source is endogenous or exogenous. Therefore a method was developed to determine the ¹³C/¹²C ratios of Bo, BM1, pregnanediol, androsterone, etiocholanolone, and testosterone from a single urine specimen. The validity of the method was ensured by repeated processing of urine fortified with 2–50 ng/mL Bo and BM1. The specificity of the method was ensured by gas chromatography/mass spectrometry determinations. Out of 23 samples investigated throughout the last four years, 11 showed ¹³C/¹²C ratios of Bo or BM1 inconsistent with an exogenous origin. Two of these samples were collected from the same athlete within a one‐month interval, strongly indicating the chance of endogenous Bo production by this athlete. Copyright © 2010 John Wiley & Sons, Ltd.     

The influence of small doses of ethanol on the urinary testosterone to epitestosterone ratio in men and women

Endogenous steroid use can increase urinary testosterone/epitestosterone (T/E) values. In addition, ethanol in amounts >0.5 g per kg of body weight (g/kg) can also increase T/E values. However, the effect of smaller doses of ethanol on T/E values is unknown. The influence of 0.2 and 0.4 g/kg of ethanol on baseline T/E values in 20 men and 20 women with low and high baseline T/E values was investigated and correlated with ethyl glucuronide (EtG) and ethyl sulfate (EtS) concentrations. T/E values for 7 of the women were excluded from the study because of undetectable T concentrations or for other reasons. One man and 1 woman with a high T/E baseline value had a significant increase in their T/E value after ingestion of 0.2 g/kg of ethanol. One man and 2 women with a high T/E baseline, and 1 woman with a low T/E baseline had significantly increased T/E values after ingestion of 0.4 g/kg of ethanol. There was wide variability in peak EtG concentrations and a lack of correlation between ethanol dose and EtG concentrations. Interestingly, 1 man and 2 women with increased T/E values following ethanol ingestion had EtG concentrations below the World Anti‐Doping Agency (WADA) cut‐off of 5000 ng/mL. These findings demonstrate that small amounts of ethanol can elevate T/E values, with women being more susceptible. In addition, consideration should be given to the lowering of the WADA EtG cut‐off to detect samples with elevated T/E values from ingestion of low doses of ethanol.     

False negative results in testosterone doping in forensic cases: Sensitivity of the urinary detection criteria T/E and T/LH

At the Swedish national forensic toxicology laboratory, a measured testosterone/epitestosterone (T/E) ratio ≥ 12 together with testosterone/luteinizing hormone (T/LH) in urine > 400 nmol/IU is considered as a proof of exogenous testosterone administration. However, according to the rules of the World Anti-Doping Agency (WADA), samples with T/E ratio > 4 are considered suspicious and shall be further analysed by gas chromatography–combustion–isotope ratio mass spectrometry (GC-C-IRMS) to confirm the origin of testosterone and its metabolites. The aim of this study was to investigate the possibility of false negative results and to estimate the frequency of negative results using the current criteria for detection of abuse of testosterone in forensic investigations. Urine and serum samples were collected by the police at suspected infringement of the doping law in Sweden. Fifty-eight male subjects were included in the study. Urinary testosterone was determined by gas chromatography–mass spectrometry (GC–MS), serum testosterone and LH—by immunoassay. The origin of testosterone and its metabolites was confirmed by means of GC-C-IRMS. Twenty-six of the 57 analysed subjects tested positive for exogenous testosterone using the criteria T/E ≥ 12 combined with T/LH > 400 nmol/IU. The IRMS analyses confirmed 47 positives; thus, 21 were considered false negatives. Negative predictive value was 32% (95% confidence interval [CI]: 16%–50%) and sensitivity 55%. No false positive subjects were found. The number of false negative cases using the current criteria for the detection of testosterone abuse and hence the low sensitivity indicates a need to discuss introduction of new strategies in forensic doping investigations.     

Inter‐individual variation of the urinary steroid profiles in Swedish and Norwegian athletes

The steroidal module of the Athlete Biological Passport (ABP) aims to detect doping with endogenous steroids, e.g. testosterone (T), by longitudinally monitoring several biomarkers. These biomarkers are ratios combined into urinary concentrations of testosterone and metabolically related steroids. However, it is evident after 5 years of monitoring steroid passports that there are large variations in the steroid ratios complicating its interpretation. In this study, we used over 11000 urinary steroid profiles from Swedish and Norwegian athletes to determine both the inter‐ and intra‐individual variations of all steroids and ratios in the steroidal passport. Furthermore, we investigated if the inter‐individual variations could be associated with factors such as gender, type of sport, age, time of day, time of year, and if the urine was collected in or out of competition. We show that there are factors reported in today's doping tests that significantly affect the steroid profiles. The factors with the largest influence on the steroid profile were the type of sport classification that the athlete belonged to as well as whether the urine was collected in or out of competition. There were also significant differences based on what time of day and time of year the urine sample was collected. Whether these significant changes are relevant when longitudinally monitoring athletes in the steroidal module of the ABP should be evaluated further.     

Screening of non‐steroidal anti‐inflammatory drugs for inhibitory effects on the activities of six UDP‐glucuronosyltransferases (UGT1A1, 1A3, 1A4, 1A6, 1A9 and 2B7) using LC‐MS/MS

Non‐steroidal anti‐inflammatory drugs (NSAIDs) are used widely to relieve pain and to decrease inflammation. Several clinical studies have reported that NSAIDs inhibit uridine 5′‐diphospho‐glucuronosyltransferase (UGT) enzymes. Therefore, the study evaluated the inhibitory potential of 15 NSAIDs on the activities of six UGT isoforms (i.e. UGT1A1, 1A3, 1A4, 1A6, 1A9 and 2B7) in human liver microsomes (HLMs). Among the 15 NSAIDs tested here, mefenamic acid and diclofenac inhibited all UGTs tested in this study. Piroxicam and niflumic acid inhibited UGT1A9 activity (IC₅₀ = 73.8 μm and 0.38 μm , respectively) and naproxen selectively inhibited UGT2B7 activity (IC₅₀ = 53.1 μm ), whereas it did not inhibit the other UGTs tested (IC₅₀ > 200 μm ). Diflunisal inhibited the UGT1A1 (IC₅₀ = 33.0 μm ) and UGT1A9 (IC₅₀ = 19.4 μm ). Acetaminophen, fenoprofen, ibuprofen, ketoprofen, meloxicam, phenylbutazone, salicylic acid and sulindac showed negligible inhibitory effects on the six UGTs (IC₅₀ > 100 μm ). These results suggest that some NSAIDs have the potential to inhibit UGTs in vitro. Copyright © 2014 John Wiley & Sons, Ltd.     

焦磷酸测序技术检测UGT1A3和UGT2B7在中国汉族人群中的基因多态性

目的建立焦磷酸测序技术(pyrosequencing)研究二相代谢酶UGT1A3和UGT2B7基因多态性在中国汉族人群中的分布。方法应用带生物素标记扩增引物并经PCR扩增和Beads分离,制备UGT1A3和UGT2B7焦磷酸测序单倍摸板。在PYroMarkID焦磷酸测序上进行焦磷酸测序,检测233血样的DNA标本的17个SNP位点,以确定血样DNA标本的的基因型。结果 233例血样的DNA标本中,UGT1A3等位基因有9种表型,分别为UGT1A3*1*1、UGT1A3*1*2、UGT1A3*1*3、UGT1A3*1*4、UGT1A3*1*5、UGT1A3*2*3、UGT1A3*2*4、UGT1A3*3*3和UGT1A3*3*5。UGT2B7-1和UGT2B7-2各有3种基因型,分别为G/G型、G/T型、T/T和C/C型、C/T型、T/T型。结论我国汉族人群中UGT1A3和UGT2B7基因突变较高。     

Involvement of CYP2C9 and UGT2B7 in the metabolism of zaltoprofen,a nonsteroidal anti-inflammatory drug,and its lack of clinically significant CYP inhibition potential

AIMS: To identify the cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) isoforms responsible for the formation of the primary metabolite(s) of zaltoprofen, and to predict possible drug interactions by investigating the inhibition of CYP isoforms in vitro. METHODS: The metabolism of zaltoprofen was studied in vitro using recombinant CYP and UGT isoform cDNA-expression systems. The effects of selective isoform inhibitors on zaltoprofen metabolism were studied using human liver microsomes. The inhibitory effects of zaltoprofen on the metabolism of selective probe substrates for CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4 were also determined in human liver microsomes. RESULTS: Zaltoprofen was extensively metabolized by CYP2C9 and UGT2B7. CYP2C9 catalysed sulphoxidation but not hydroxylation of zaltoprofen. In the human liver microsomal metabolism study, zaltoprofen metabolism was markedly inhibited by sulphaphenazole, a selective inhibitor of CYP2C9. In the drug interaction study, negligible inhibition (< 15%) of the activities of CYP1A2, CYP2C19, CYP2D6, CYP2E1 and CYP3A4 was apparent at 5 micro g ml(-1), the maximum plasma concentration observed in humans after oral administration of an 80 mg zaltoprofen tablet. However, zaltoprofen inhibited CYP2C9 by 26% at 5 micro g ml(-1). At higher concentrations, zaltoprofen produced some inhibition of CYP2C9 (IC50 = 19.2 micro g ml(-1); 64.4 micro m) and CYP3A4 (IC50 = 53.9 micro g ml(-1); 181 micro m). The free drug concentrations in plasma (0.02 micro g ml(-1), 67.0 nm) at the Cmax of the clinically effective doses are much lower than the IC50 values corrected for the nonspecific binding ratio of zaltoprofen to microsomal protein (15.5 micro g ml(-1) for CYP3A4, 49.5 micro g ml(-1) for CYP3A4). Furthermore, the maximum free drug concentrations in the hepatic intracellular was calculated to be 0.068 micro g ml(-1) and the increase in the AUC in the presence of zaltoprofen was estimated to be only 0.4% for CYP2C9 substrates and 0.1% for CYP3A4 substrates, respectively. CONCLUSIONS: Zaltoprofen is predominantly metabolized by CYP2C9 and UGT2B7, and is considered unlikely to cause significant drug interactions in vivo when coadministered with CYP substrates at clinically effective doses.     

Synthesis and in vitro evaluation of 2‐[11C]methoxyestradiol‐3,17β‐O,O‐bissulfamate for in vivo studies of angiogenesis

In the present study, 2‐methoxyestradiol‐3,17β‐O,O‐bissulfamate (1), a known angiogenesis inhibitor, was prepared in a radiolabeled form by ¹¹C‐methylation of 2‐hydroxyestradiol‐3,17β‐O,O‐bis(N‐trityl)sulfamate (6) followed by detritylation. Synthesis of precursor 6 required a rather long step because of the presence of two sulfamoyl groups. The decay‐corrected radiochemical yield of [¹¹C]1 was 19 ± 2% based on [¹¹C]CH₃I, and the specific activity was 34–39 GBq/µmol. Although 1 is known to significantly inhibit the proliferation of human umbilical vascular endothelial cells (HUVECs), its radiolabeled form, [¹¹C]1 was not avidly taken up by HUVECs, and the uptake increased slightly in a time‐dependent manner (156% at 60 min relative to a value of 100% at 5 min). These results suggest that further studies are warranted to determine the molecular target for [¹¹C]1. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of 13C215N2‐labeled anti‐inflammatory and cytoprotective tricyclic bis(cyanoenone) ([13C215N2]‐TBE‐31) as an internal standard for quantification by stable isotope dilution LC‐MS method

Tricyclic bis(cyanoenone), TBE‐31, one of the most potent activators of the Keap1/Nrf2/antioxidant response element pathway, has been developed as a new anti‐inflammatory and cytoprotective agent. ¹³C₂¹⁵N₂‐labeled TBE‐31 ([¹³C₂¹⁵N₂]‐TBE‐31), which has two ¹³C and two ¹⁵N atoms in two cyano groups, was designed to develop a method for quantification of cell, tissue, and plasma levels of TBE‐31 that involves chromatography/mass spectrometry coupled with the use of a stable isotope‐labeled internal standard. [¹³C₂¹⁵N₂]‐TBE‐31 was successfully synthesized in four steps from a previously reported intermediate, which is prepared in 11 steps from cyclohexanone, by introduction of two ¹³C atoms with ethyl [¹³C]formate and two ¹⁵N atoms with hydroxyl[¹⁵N]amine. The stable isotope dilution liquid chromatography–mass spectrometry method for quantification of TBE‐31 was successfully developed using [¹³C₂¹⁵N₂]‐TBE‐31 to compensate for any variables encountered during sample processing and analysis.     

Expression of pro‐inflammatory cytokines and mediators induced by Bisphenol A via ERK‐NFκB and JAK1/2‐STAT3 pathways in macrophages

Macrophages not only play an important role in the innate immune response but also participate in many inflammatory and infectious diseases including asthma, diabetes, obesity, cardiovascular diseases, and cancers. Bisphenol A (BPA) is the most commonly used component for plastic products. However, BPA is an endocrine disruptor for mammals and participates in several inflammatory and infectious diseases. Up until now, there are no researches demonstrated the potential role of BPA in macrophage activation and its relative mechanism. BPA promoted the generation of proinflammatory cytokines IL‐1β, IL‐6, and TNFα in a concentration‐dependent manner (P < 0.05). BPA was identified to increase the expression of proinflammatory mediators NO and PGE2, and its upstream factors iNOS, COX2, and cPLA2 in a concentration‐dependent manner (P < 0.05). Phosphorylation and nuclear translocation of NF‐κB p65 were significantly induced by BPA via IκB degradation (P < 0.05). In addition, phosphorylation of ERK significantly induced by BPA at a concentration which was less than that for phosphorylation of p38 MAPK and JNK (P < 0.05). Furthermore, phosphorylation of STAT3 significantly induced by BPA at a concentration lower than that for phosphorylation of STAT1 (P < 0.05). Phosphorylation of JAK1 and JAK2 was also significantly induced by BPA in a concentration‐dependent manner (P < 0.05).     

围刺配合电针对乳腺增生大鼠血清激素水平和乳腺组织形态、ER 表达的影响

目的观察围刺配合电针对乳腺增生大鼠血清性激素雌与孕激素的比值（E2／P）、泌乳素（PRL）、睾酮（T）、乳腺组织形态和乳腺组织ER表达的影响,以探讨干预治疗乳腺增生的作用机制。方法随机将40只Wistar大鼠分为模型组、针刺组、三苯氧胺组及正常组,每组10只。采用己烯雌酚联合黄体酮肌内注射进行造模。针刺组：将大鼠固定,分别围刺第2对左右乳房后,接通电针仪持续刺激30min,并针刺膻中穴,留针30min;三苯氧胺组予三苯氧胺1．8mg／kg灌胃治疗,1次／d,共30d。于末次治疗后测定血清E2、P、PRL、T含量,计算E2／P比值;取大鼠第2对乳房常规HE染色,光镜下观察组织形态表现;运用免疫组化法对乳房乳腺组织中ER表达情况进行观察。结果治疗后E2／P：针刺组与三苯氧胺组比值均低于模型组（P〈0．05）。PRL：针刺组和三苯氧胺组均低于模型组（P〈0．05）;针刺组与三苯氧胺组比较差异有统计学意义（P〈0．05）。T：针刺组和三苯氧胺组均低于模型组（P〈0．05）。乳腺组织ER表达：针刺组和三苯氧胺组大鼠乳腺组织ER阳性细胞表达情况显著降低,AOD值低于正常组（P〈0．05）。结论围刺配合电针具有降低模型大鼠乳头高度、缩小乳头直径,改善血清E2／P、PRL、T紊乱状态和乳腺组织病理形态,降低乳腺增生模型大鼠乳腺组织ER表达的作用。     

Role of NF‐κB activation and Th1/Th2 imbalance in pulmonary toxicity induced by nano NiO

With the progress of nanotechnology, nano nickel oxide (NiO) has been extensively used as sensors, battery electrodes, catalysts, and cosmetics. Previous researches verified that nano NiO could exert pulmonary toxicity, but its mechanism was unclear. To shed light upon this, the role of nuclear factor‐κ B (NF‐κ B) activation and Th1/Th2 imbalance were to explore in pulmonary damage induced by nano NiO. Male Wistar rats were randomized into control group, nano NiO groups (0.015, 0.06, and 0.24 mg kg^?1) and micro NiO group (0.024 mg kg^?1) and treated by intratracheal instillation twice a week for 6 weeks. The results showed that the abnormal changes induced by nano NiO were found on indicators of nitrative stress (NO, TNOS, and iNOS), inflammatory cytokines (TNF‐α , IL‐2, and IL‐10) and cytokine‐induced neutrophil chemoattractants (CINC‐1, CINC‐2αβ , and CINC‐3) in lung tissue. In addition, nano NiO instillation induced the upregulated mRNA and protein expression of NF‐κ B, inhibitor of κB kinase‐α (IKK‐α ) and nuclear factor‐inducing kinase (NIK). The protein content of GATA‐3 increased as well as T‐bet decreased in nano NiO groups, and the ratio of T‐bet/GATA‐3, as a key evaluation indicator of Th1/Th2 balance, was lower than the control group. The findings indicated that nano NiO could enhance the nitrative stress and inflammatory response in lung tissue, and its mechanism was related to the NF‐κ B activation and Th1/Th2 imbalance. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1354–1362, 2017.     

Drug‐drug interaction and doping,part 2: An in vitro study on the effect of non‐prohibited drugs on the phase I metabolic profile of stanozolol

The present study was designed to provide preliminary information on the potential impact of metabolic drug‐drug interaction on the effectiveness of doping control strategies currently followed by the anti‐doping laboratories to detect the intake of prohibited agents. In vitro assays based on the use of human liver microsomes and recombinant cytochrome P450 isoforms were developed and applied to characterize the phase I metabolic profile of the prohibited agent stanozolol, both in the absence and in the presence of substances (ketoconazole, itraconazole, miconazole, cimetidine, ranitidine, and nefazodone) not included in the World Anti‐Doping Agency (WADA) list of prohibited substances and methods and frequently administered to athletes. The results show that the in vitro model utilized in this study is adequate to simulate the in vivo metabolism of stanozolol. Furthermore, our data showed that ketoconazole, itraconazole, miconazole, and nefazodone caused a marked modification in the production of the metabolic products (3’‐hydroxy‐stanozolol, 4β‐hydroxy‐stanozolol and 16β‐hydroxy‐stanozolol) normally selected by the anti‐doping laboratories as target analytes to detect stanozolol intake. On the contrary, moderate variations were registered in the presence of cimetidine and no significant modifications were measured in the presence of ranitidine. This evidence confirms that the potential effect of drug‐drug interactions is duly taken into account also in anti‐doping analysis. Copyright © 2014 John Wiley & Sons, Ltd.     

Bufalin inhibits migration and invasion in human hepatocellular carcinoma SK‐Hep1 cells through the inhibitions of NF‐kB and matrix metalloproteinase‐2/‐9‐signaling pathways

Metastasis plays an important role in mortality of cancer patients. Migration and invasion are the major characteristics of tumor metastasis. The induction of matrix metalloproteinases (MMPs) such as MMP‐2 and ‐9 are particularly important for the invasiveness of various cancer cells. Bufalin, a class of toxic steroids, was purified from the skin glands of Bufo gargarizans or Bufo melanostictus; it is known to inhibit proliferation of human cancer cells. In this study, we investigated the antiinvasive mechanisms of bufalin in the human hepatocellular cancer cell line SK‐Hep1. Bufalin significantly reduced serum‐induced cell invasion and migration. Furthermore, bufalin markedly inhibited MMP‐2 and ‐9 activity, mRNA expression and protein levels in SK‐Hep1 cells. Bufalin attenuated phosphoinisitide‐3‐kinase (PI3K) and phosphorylation of AKT which was associated with reduced levels of nuclear factor kappa B (NF‐κB). Bufalin also suppressed protein levels of FAK and Rho A, VEGF, MEKK3, MKK7, and uPA and it diminished NF‐κB translocation. Based on these observations, we propose that bufalin is acts as an antiinvasive agent by inhibiting MMP‐2 and ‐9 and involving PI3K/AKT and NF‐κB pathways. Bufalin is a potential therapeutic agent that may have efficacy in preventing the invasion and metastasis of malignant liver tumors. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 74–82, 2015.     

Pharmacokinetic evaluation and studies on the clinical efficacy of guar gum‐–based oral drug delivery systems of albendazole and albendazole‐β‐cyclodextrin for colon‐targeting in human volunteers

The present investigation assessed the in vivo properties of the guar gum–based colon‐targeted matrix tablets of albendazole‐β‐cyclodextrin (KA), albendazole matrix tablet (GA), and an immediate‐release albendazole tablet (CA) in humans. A single oral dose was administered in healthy human volunteers and a completely randomized, two‐way, three‐period crossover design was adopted. The data were statistically analyzed and a value of P<0.05 was considered statistically significant. In healthy human volunteers, guar gum colon‐targeted tablets showed delayed t_max and absorption time, decreased absorption rate constant, and unaltered t_1/2indicating that albendazole is not released in stomach and small intestine, but is delivered to the colon, resulting in a slow absorption of the drug and making the drug available for local action in the colon. The increase in C_max and AUC_0‐∞ of KA shows that the bioavailability of albendazole in humans could be definitely improved by complexing the drug with β‐cyclodextrin. Furthermore, an open, parallel, single‐blind clinical study was conducted in patient volunteers who had helminthiasis. Clinical studies showed that the guar gum colon‐targeted tablets could reduce eggs per gram faster than conventional tablets could, resulting in improved clinical symptoms, Hb content, and decreased total count as compared to conventional tablets of albendazole. The investigation shows that albendazole, when complexed with β‐cyclodextrin, improves in vivo bioavailability of the drug and colon targeting using guar gum ensures drug delivery in the colonic fluids, and therefore improves clinical efficacy in human beings with helminthiasis. Drug Dev. Res. 67:154–165, 2006. © 2006 Wiley‐Liss, Inc.