Quantitative Prediction of Oral Bioavailability of a Lipophilic Antineoplastic Drug Bexarotene Administered in Lipidic Formulation Using a Combined In Vitro Lipolysis/Microsomal Metabolism Approach

For performance assessment of the lipid-based drug delivery systems (LBDDSs), in vitro lipolysis is commonly applied because traditional dissolution tests do not reflect the complicated in vivo micellar formation and solubilization processes. Much of previous research on in vitro lipolysis has mostly focused on rank-ordering formulations for their predicted performances. In this study, we have incorporated in vitro lipolysis with microsomal stability to quantitatively predict the oral bioavailability of a lipophilic antineoplastic drug bexarotene (BEX) administered in LBDDS. Two types of LBDDS were applied: lipid solution and lipid suspension. The predicted oral bioavailability values of BEX from linking in vitro lipolysis with microsomal stability for lipid solution and lipid suspension were 34.2 ± 1.6% and 36.2 ± 2.6%, respectively, whereas the in vivo oral bioavailability of BEX was tested as 31.5 ± 13.4% and 31.4 ± 5.2%, respectively. The predicted oral bioavailability corresponded well with the oral bioavailability for both formulations, demonstrating that the combination of in vitro lipolysis and microsomal stability can quantitatively predict oral bioavailability of BEX. In vivo intestinal lymphatic uptake was also assessed for the formulations and resulted in <1% of the dose, which confirmed that liver microsomal stability was necessary for correct prediction of the bioavailability.     

液相色谱-串联四极杆质谱测定中药及保健品中非法添加8种化学降糖药

目的建立液相色谱-串联四极杆质谱法检测降糖类中药及保健食品违禁添加的8种化学药物。方法采用ZORBAX SB-C18柱,分别以0.1%甲酸(用氨水调节pH至3.5)-乙腈进行梯度洗脱,检测波长240nm,采用正离子扫描模式,8种药物的检测限为0.5~8ng.mL-1,通过与标准图库中保留时间和MRM图谱比较,以及参照一级、二级图谱比较,筛查出样品中违法违禁添加的8种药物,并通过MRM模式,对供试品进行初步定量。结果与结论在103批供试品中,分别检测到二甲双胍、苯乙双胍、格列本脲、盐酸格列吡嗪、格列齐特、格列喹酮等8种化学降糖药。     

Bariatric surgery in severely obese adolescents improves major comorbidities including hyperuricemia

Objective

Serum uric acid (sUA) is believed to contribute to the pathogenesis of metabolic comorbidities like hypertension, insulin-resistance (IR) and endothelial dysfunction (EDF) in obese children. The present pilot study investigated the association between sUA concentrations and loss of body weight following laparoscopic sleeve gastrectomy (LSG) or laparoscopic Roux-en-Y-gastric bypass (RYGB) in severely obese adolescents.

Materials/Methods

10 severely obese adolescents underwent either LSG (n = 5) or RYGB (n = 5). 17 normal weight, healthy, age- and gender-matched adolescents served as a normal weight peer group (NWPG). Pre- and 12 months postoperatively, sUA and relevant metabolic parameters (glucose homeostasis, transaminases, lipids) were compared.

Results

Preoperatively, sUA was significantly elevated in patients with severe obesity compared to NWPG. Twelve months after LSG and RYGB, a significant decrease in sUA, BMI, CVD risk factors, hepatic transaminases, and HOMA-IR was observed. Reduction in SDS-BMI significantly correlated with changes in sUA.

Conclusions

sUA levels and metabolic comorbidities improved following bariatric surgery in severely obese adolescents. The impact of changes in sUA on long-term clinical complications of childhood obesity deserves further study.     

Magnetic resonance microscopy of mammalian neurons

Magnetic resonance imaging (MRI) is now a leading diagnostic technique. As technology has improved, so has the spatial resolution achievable. In 1986 MR microscopy (MRM) was demonstrated with resolutions in the tens of micrometers, and is now an established subset of MRI with broad utility in biological and non-biological applications. To date, only large cells from plants or aquatic animals have been imaged with MRM limiting its applicability. Using newly developed microsurface coils and an improved slice preparation technique for correlative histology, we report here for the first time direct visualization of single neurons in the mammalian central nervous system (CNS) using native MR signal at a resolution of 4–8 μm. Thus MRM has matured into a viable complementary cellular imaging technique in mammalian tissues.     

Simultaneous detection and quantitation of organic impurities in methamphetamine by ultra‐high‐performance liquid chromatography–tandem mass spectrometry,a complementary technique for methamphetamine profiling

The analysis of organic impurities plays an important role in the impurity profiling of methamphetamine, which in turn provides valuable information about methamphetamine manufacturing, in particular its synthetic route, chemicals, and precursors used. Ultra‐high‐performance liquid chromatography – tandem mass spectrometry (UHPLC – MS/MS) is ideally suited for this purpose due to its excellent sensitivity, selectivity, and wide linear range in multiple reaction monitoring (MRM) mode. In this study, a dilute‐and‐shoot UHPLC – MS/MS method was developed for the simultaneous identification and quantitation of 23 organic manufacturing impurities in illicit methamphetamine. The developed method was validated in terms of stability, limit of detection (LOD), lower limit of quantification (LLOQ), accuracy, and precision. More than 100 illicitly prepared methamphetamine samples were analyzed. Due to its ability to detect ephedrine/pseudoephedrine and its high sensitivity for critical target markers (eg, chloro‐pseudoephedrine, N‐cyclohexylamphetamine, and compounds B and P), more impurities and precursor/pre‐precursors were identified and quantified versus the current procedure by gas chromatography – mass spectrometry (GC – MS). Consequently, more samples could be classified by their synthetic routes. However, the UHPLC – MS/MS method has difficulty in detecting neutral and untargeted emerging manufacturing impurities and can therefore only serve as a complement to the current method. Despite this deficiency, the quantitative information acquired by the presented UHPLC – MS/MS methodology increased the sample discrimination power, thereby enhancing the capacity of methamphetamine profiling program (MPP) to conduct sample‐sample comparisons.     

液质联用法测定七宝美髯丸中5种成分的含量

目的：建立UPLC-PDA-MS/MS法同时测定七宝美髯丸中二苯乙烯苷、阿魏酸、金丝桃苷、补骨脂素、异补骨脂素的含量。方法：采用InertSustain^® C₁₈（3.0 mm×100 mm,3.0 μm）色谱柱,甲醇-0.05%甲酸水溶液,梯度洗脱,流速0.4 mL·min^-1,进样量10 μL;PDA扫描范围：200~400 nm;质谱采用电喷雾离子源（ESI源）,正负离子扫描切换,多重反应监测模式进行定量分析。结果：七宝美髯丸中5种成分在线性范围内峰面积与质量浓度均呈良好的线性关系,加样回收率为99.06%~102.24%,精密度RSD值小于2%。在所设定的色谱条件下,七宝美髯丸中5个成分（二苯乙烯苷、阿魏酸、金丝桃苷、补骨脂素和异补骨脂素）于10 min内完全分离。结论：建立的UPLC-PDA-MS/MS方法快速简便、精密度好、灵敏度高,可用于七宝美髯丸中多种成分的含量测定和质量控制。     

Dynamic MR-Mammography as the best method for diagnosis of invasive lobular breast carcinoma: A retrospective study

Aim of the study

It is a retrospective study aiming to provide diagnostic characterization of ILC in Dynamic MR-Mammography and to compare its diagnostic performance to mammography and ultrasonography.

Material and Method

A total of 56 cases of ILC were selected in retrospective review of mammography, ultrasonography and Dynamic MRM of 420 patients with invasive breast cancer.

Results

Asymmetric density was the commonest mammography finding and the measured sensitivity of mammography in detecting ILC was 87.5% (9/56 FN).The most common US manifestation of ILC was focal shadowing without a discrete mass and its sensitivity in detecting ILC was 84.9% (10/56 FN). At MR imaging, the most common manifestation of ILC was a solitary irregular or angular mass with speculated or ill-defined margins (33.9%of cases [n = 19]).The measured sensitivity is 96.5% (2/56 FN). Additional data such as those affected the patient management including the presence of multifocal or multicentric disease, chest wall involvement and contralateral breast cancer were encountered in 48.2% of cases [n = 27]. ILC has a tendency to demonstrate delayed maximum enhancement with washout exhibited by only a minority of lesions (21.4% [n = 12]).

Conclusion

MR imaging has proved to be superior to mammography and US in the detection and management of ILC. It provides useful information for further management and pre-surgical planning.     

UHPLC-MS/MS测定天仙藤中5种马兜铃酸类成分

目的 建立天仙藤中马兜铃酸类成分的液质联用检测分析方法。方法 采用Agilent SB-C₁₈(2.1 mm×50 mm,1.8 μm)色谱柱,以乙腈-体积分数0.1%-甲酸溶液为流动相梯度洗脱,流速0.3 mL·min^-1,以多反应监测模式,建立了同时测定天仙藤中马兜铃内酰胺AⅡ(ALAⅡ)、马兜铃酸Ⅳa(AAⅣa)、马兜铃内酰胺FⅠ(ALFⅠ)、马兜铃内酰胺Ⅰ(ALⅠ)和马兜铃酸Ⅰ(AAⅠ)共5种马兜铃酸类成分的液质联用检测方法。结果 ALAⅡ、AAⅣa、ALFⅠ、ALⅠ和AAⅠ分别在1.12~22.34、258.60~10 344.10、0.98~19.52、11.64~232.85、90.70~2 267.41 ng·mL^-1内线性关系良好;平均加样回收率分别为100.9%(相对标准偏差RSD 4.53%)、105.2%(RSD 4.83%)、102.6%(RSD 8.54%)、104.6%(RSD 3.64%)、114.6%(RSD 3.50%)。一共9批样品,其中有4批均检出上述5种马兜铃酸类成分;4批样品均检出除ALFⅠ外的其余4种马兜铃酸类成分;1批样品未检出AAI,检出其余4种马兜铃酸类成分。结论 上述建立的同时测定2种马兜铃酸和3种马兜铃内酰胺成分的液质联用方法经验证准确、可靠,能够用于马兜铃酸类成分的检测与分析。     

A UPLC–MS/MS method for in vivo and in vitro pharmacokinetic studies of psoralenoside,isopsoralenoside, psoralen and isopsoralen from Psoralea corylifolia extract

Ethnopharmacological relevance

The dried fruit of Psoralea corylifolia L. has been used to prevent and treat vitiligo, osteoporosis, arthralgia and asthma in Traditional Chinese Medicine for some 1600 years. Psoralen (P), isopsoralen (IP), psoralenoside (PO) and isopsoralenoside (IPO) are the major coumarins and coumarin-related benzofuran glycosides in Psoraleae Fructus, which have been reported to show estrogen-like activity, osteoblastic proliferation accelerating activity, antitumor effects and antibacterial activity. The first aim of this study is to develop a rapid, sensitive and selective ultra performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) approach for simultaneous determination of PO, IPO, P and IP in rat plasma and samples collected from in vitro incubation experiments. The second aim is to investigate the pharmacokinetic properties of PO, IPO, P and IP after oral administration of Psoralea corylifolia extract (PCE) to rats. The third aim is to confirm the biotransformation of PO to P or IPO to IP under gastrointestinal conditions.

Materials and methods

A UPLC–MS/MS method with a C18 column and a mobile phase of methanol-0.1% aqueous formic acid was validated according to the criteria in FDA guidelines about bioanalytical method, which was developed to investigate the pharmacokinetic behavior of PO, IPO, P and IP from PCE and the metabolic pathways of PO to P or IPO to IP.

Results

The criteria for establishment of a new UPLC–MS/MS method including selectivity, linearity, accuracy, precision, extraction recovery, matrix effect and stability were validated. This method was successfully applied to the quantitative determination of PO, IPO, P and IP in biological samples collected from both in vitro incubations and in vivo rat experiments. After oral administration of PCE to rat, pharmacokinetic parameters of these four compounds indicated that in vivo biotransformation may occur between PO and P or IPO and IP. Purified benzofuran glycosides fraction (PBGF), containing only PO and IPO, was orally administered to rats to further confirm the biotransformation of PO to P or IPO to IP under gastrointestinal conditions. An in vitro incubation study elucidated that PO and IPO were metabolized to P and IP by intestinal microflora through de-glucosylation.

Conclusions

This paper developed a rapid, sensitive and selective UPLC–MS/MS method for simultaneous determination of PO, IPO, P and IP from PCE in biological samples, and investigated on their comprehensive in vivo and in vitro pharmacokinetic studies. These obtained results showed that the metabolism by intestinal bacteria plays an important role in pharmacological effects of orally administered PCE.