金水宝胶囊生产过程中质量控制方法的建立

目的:完善金水宝胶囊生产过程中的质量控制体系,为该制剂的后续研究与应用提供实验依据。方法:采用高效液相色谱法(HPLC),Ultimate AQ-C18色谱柱(4.6 mm×150 mm,5μm),腺苷、鸟苷、尿苷含量测定的色谱条件为流动相甲醇(A)-0.1%甲酸水溶液(B)梯度洗脱(0~14 min,100%~99%B;14~19 min,99%~89%B;19~39 min,89%~85%B),流速0.4 m L·min^-1,柱温30℃,进样量10μL,检测波长260 nm。麦角甾醇含量测定的色谱条件为流动相甲醇-水(98∶2),流速1 m L·min^-1,柱温25℃,进样量10μL,检测波长283 nm。结果:发酵虫草菌粉不同生产阶段样品的指纹图谱中主要色谱峰差异性较小。腺苷、鸟苷、尿苷的线性关系良好(R2均>0.999);三者的加样回收率分别为106.06%,101.25%,105.88%,RSD均<3.0%。于2016-2018年各抽取的20批样品中腺苷、麦角甾醇的含量均符合2015年版《中国药典》的要求,鸟苷、尿苷的质量分别为0.97~1.36,0.67~1.38 mg/粒。结论:市面所售金水宝胶囊质量较为稳定。建立的方法可用于检测金水宝胶囊的质量,且操作简便、稳定可靠,可为发酵虫草菌粉类产品的检测提供参考。     

Physiologically-based pharmacokinetic modeling for mirabegron: a multi-elimination pathway mediated by cytochrome P450 3A4, uridine 5'-diphosphate-glucuronosyltransferase 2B7, and butyrylcholinesterase

1. This was the first study to construct a physiologically-based pharmacokinetic (PBPK) model for mirabegron which incorporates the overall elimination pathways of metabolism by cytochrome P450 (CYP) 3A4, uridine 5'-diphosphate-glucuronosyltransferase (UGT) 2B7, and butyrylcholinesterase (BChE) and renal excretion. The objective was to assess the risk of drug-drug interactions (DDIs) by estimating the contribution of each elimination pathway and simulating the magnitude of the DDIs with UGT2B7 inhibitors.

2. A PBPK model for mirabegron was constructed to reproduce the plasma concentration-time curves from a phase 1 study and the magnitude of the DDI with ketoconazole taking into account the overall elimination pathways. The PBPK model was subsequently verified using data from other DDI studies.

3. The constructed PBPK model estimated the contribution for each elimination pathway: 44% and 29% for CYP3A4 and UGT2B7 in the liver, 1.6% for UGT2B7 in the kidney, 3.2% for BChE in plasma, and 22% for renal excretion.

4. Co-administration of probenecid (an UGT2B7 inhibitor) or fluconazole (an UGT2B7 and CYP3A4 inhibitor) was predicted to increase area under the curve for mirabegron to 115% or 174%, respectively.

5. In conclusion, PBPK modeling and simulation revealed a low DDI risk for mirabegron following co-administration with BChE or UGT2B7 inhibitors.

     

Carboxylesterase catalyzed 18O-labeling of carboxylic acid and its potential application in LC-MS/MS based quantification of drug metabolites

LC-MS quantification of drug metabolites is sometimes impeded by the availability of internal standards that often requires customized synthesis and/or extensive purification. Although isotopically labeled internal standards are considered ideal for LC-MS/MS based quantification, de novo synthesis using costly isotope-enriched starting materials makes it impractical for early stage of drug discovery. Therefore, quick access to these isotope-enriched compounds without chemical derivatization and purification will greatly facilitate LC-MS/MS based quantification. Herein, we report a novel ¹⁸O-labeling technique using metabolizing enzyme carboxylesterase (CES) and its potential application in metabolites quantification study. Substrates of CES typically undergo a two-step oxygen exchange with H₂¹⁸O in the presence of the enzyme, generating singly- and doubly-¹⁸O-labeled carboxylic acids; however, unexpected hydrolytic behavior was observed for three of the test compounds – indomethacin, piperacillin and clopidogrel. These unusual observations led to the discovery of several novel hydrolytic mechanisms. Finally, when used as internal standard for LC-MS/MS based quantification, these in situ labeled compounds generated accurate quantitation comparable to the conventional standard curve method. The preliminary results suggest that this method has potential to eliminate laborious chemical synthesis of isotope-labeled internal standards for carboxylic acid-containing compounds, and can be developed to facilitate quantitative analysis in early-stage drug discovery.     

186例消化系统恶性肿瘤患者UGT1A1*6、UGT1A1*28基因多态性的检测和分析

目的：检测和分析消化系统恶性肿瘤患者UGT1A1^*6、UGT1A1^*28基因多态性。方法：收集186例消化系统恶性肿瘤患者血液标本,采用焦磷酸测序方法对UGT1A1^*6、UGT1A1^*28基因多态性进行检测,并对基因多态性频率进行统计分析。结果：186例消化系统恶性肿瘤患者样本具有群体代表性。UGT1A1^*6基因多态性为野生型G/G占比63.4%、杂合型G/A占比32.8%、突变纯合型AA占比3.8%;UGT1A1^*28基因多态性为野生型TA6/TA6占比75.8%、杂合型TA6/TA7占比21.5%、突变纯合型TA7/TA7占比2.7%;UGT1A1^*6和^*28基因多态性为野生型G/G且TA6/TA6占比48.9%,单点变异型G/G且TA6/TA7占比12.4%、G/A且TA6/TA6占比23.1%,双点变异型G/G且TA7/TA7占比2.2%、G/A且TA6/TA7占比9.1%、A/A且TA6/TA6占比3.8%,三点变异型G/A且TA7/TA7占比0.5%。患者UGT1A1^*6与UGT1A1^*28基因多态性频率分布之间具有显著性差异（P<0.05）。3个不同年龄段患者之间,胃癌、结直肠癌、其他消化系统恶性肿瘤患者之间的UGT1A1^*28、UGT1A1^*6和^*28基因型分布具有显著性差异（P<0.05）。结论：消化系统恶性肿瘤患者应用伊立替康时,应联合检测UGT1A1^*6和UGT1A1^*28基因多态性,同时密切关注患者的肿瘤类型以及年龄差异。     

一测多评法测定板蓝根中6种化学成分的含量

目的建立板蓝根Isatis indigotica中(R,S)-告依春、直铁线莲宁B、胞苷、鸟苷、尿苷、腺苷6种不同类成分的一测多评方法。方法采用HPLC法,以(R,S)-告依春为内参物,建立了(R,S)-告依春与胞苷、鸟苷、尿苷、腺苷和直铁线莲宁B的相对校正因子,并考察相对校正因子的耐用性和重现性。比较外标法和一测多评法对新疆软紫草中6种成分的测定结果。结果各相对校正因子重复性良好,一测多评法测定结果与外标法测定结果无显著差异。结论建立同时测定6种成分的一测多评法控制板蓝根的质量准确、可靠。     

Osteopontin is indispensable for activation of astrocytes in injured mouse brain and primary culture

ABSTRACT

Objectives: Osteopontin (OPN) is an inflammatory cytokine inducer involved in cell proliferation and migration in inflammatory diseases or tumors. To investigate the function of OPN in astrocyte activation during brain injury, we compared OPN-deficient (OPN/KO) with wild-type (WT) mouse brains after stab wound injury and primary culture of astrocytes.

Methods: Primary cultures of astrocytes were prepared from either WT or OPN/KO postnatal mouse brains. Activation efficiency of astrocytes in primary culture was accessed using Western blotting by examining the protein levels of glial fibrillary acidic protein (GFAP) and tenascin-C (TN-C), which are markers for reactive astrocytes, following lipopolysaccharide (LPS) stimulation. Furthermore, the stab wound injury on the cerebral cortex as a brain traumatic injury model was used, and activation of astrocytes and microglial cells was investigated using immunofluorescent analysis on fixed brain sections.

Results: Primary cultures of astrocytes prepared from WT or OPN/KO postnatal mouse brains showed that only 25% of normal shaped astrocytes in a flask were produced in OPN/KO mice. The expression levels of both GFAP and TN-C were downregulated in the primary culture of astrocytes from OPN/KO mice compared with that from WT mice. By the immunofluorescent analysis on the injured brain sections, glial activation was attenuated in OPN/KO mice compared with WT mice.

Discussion: Our data suggest that OPN is essential for proper astrocytic generation in vitro culture prepared from mouse cerebral cortex. OPN is indispensable for astrocyte activation in the mouse brain injury model and in LPS stimulated primary culture.

Abbreviations: AQP4: aquaporin 4; BBB: blood brain barrier; BrdU: bromo-deoxy uridine; CNS: central nervous system; GFAP: glial fibllirary acidic protein; IgG: immunoglobulin G; LPS: lipopolysaccharide; OPN: osteopontin; OPN/KO: osteopontin-deficient; TN-C: tenascin-C     

Quantitation of UGT1A1 in human liver microsomes using stable isotope-labelled peptides and mass spectrometry based proteomic approaches

1.?UDP-glucuronosyltransferases (UGTs) are a group of drug-metabolizing enzymes that catalyse the conjugation of endogeonous compounds and xenobiotics to yield hydrophilic glucuronides which subsequently undergo excretion. This report describes an approach for the identification and accurate quantitation of human UGT1A1 in complex biological matrices using liquid chromatography/mass spectrometry/mass spectrometry (LC-MS/MS) analysis of protein digests.

2.?A stable isotope-labelled (SIL) peptide of a unique peptide spanning residues 54–69 in exon 1 of the human UGT1A1 protein with the sequence RIYLSADPALVVIEHG was synthesized. The peptide sequence synthesized was in the reverse order of the human peptide with the stable isotope-labels in the amino acid arginine (¹³C₆¹⁵N₄) resulting in an increase in the mass of the SIL peptide of 10 amu, from 1753 to 1763. The SIL peptide was quantitated by injecting increasing concentrations of the peptide into the LC-MS to obtain a standard curve.

3.?The labelled peptide along with precursor ion monitoring was used to quantify the levels of UGT1A1 in commercial recombinant preparations (supersomes) and individual human liver microsomal samples and pooled human liver micrsomes obtained from BD Biosciences.

4.?Glucuronidation activity studies were performed, which demonstrated a positive correlation between enzyme activity levels and the UGT1A1 content in the liver microsomes obtained from individual human donors.     

Multiple variants in UGT1A1 gene are factors to develop indirect hyper-bilirubinemia

Most Taiwanese patients with hyper-bilirubinemia have genetic abnormalities in the uridine diphosphoglucuronate-glucuronosyltransferase 1A1 (UGT1A1) gene beyond the variants in the TATA box upstream of UGT1A1 associated with Gilbert’s syndrome. To investigate the role of UGT1A1 in the pathogenesis of indirect hyper-bilirubinemia, we prospectively studied 97 consecutive patients with indirect hyper-bilirubinemia for genotypes of promoter [(TA)₆TAA6, (TA)₇TAA7] and coding region [nucleotide (nt)-211, nt-686, nt-1,091 and nt-1,456] of UGT1A1. Thirty-six of the patients (45.6%) were found to have Gilbert’s syndrome with 7/7 genotype; among them, 14 also carried variants at nt-686. Forty-two patients (43.3%) had the 6/7 genotype; among them, 36 patients were found to have one or more variants in the coding region. Patients with higher serum total bilirubin are associated with higher likelihood of carrying Gilbert’s syndrome genotype: 60.0% (P=0.007) patients with serum total bilirubin level ≥2.5 mg/dL carried the Gilbert’s syndrome genotype, while only 23.9% of patients with serum total bilirubin level <2.5 mg/dL carry the same genotype (P=0.0006). Forty-one of the 61 non-Gilbert’s patients had one homogenous variants or two or more heterozygous variants in UGT1A1. Further studies are necessary to confirm the role of one homo-zygous variant or two or more hetero-zygous variants in UGT1A1 gene as factors for indirect hyper-bilirubinemia.     

Analysis of the Complicated Nonlinear Pharmacokinetics of Orally Administered Telmisartan in Rats Using a Stable Isotope-IV Method

This study aimed to kinetically analyze the nonlinear absorption and systemic exposure of telmisartan (TEL) after oral administration to rats by using a stable isotope-IV method. Rats were orally administered different dose of TEL, followed by the intravenous injection of 0.005 mg/kg of deuterium-labeled TEL (TEL-d3). Assuming that TEL-d3 shows same pharmacokinetic properties with TEL, systemic clearance (CL_tot), oral bioavailability (F_oral), and intestinal and hepatic availability (F_a*F_g, F_h) of TEL were calculated in each individual rat. AUC_po of TEL increased disproportionately with dose and showed a sigmoid-type relation, indicating the involvement of multi-nonlinear processes in oral absorption of TEL. F_a*F_g of TEL increased with dose at the low-dose range while decreased at the high-dose range. In contrast, F_h increased and CL_tot decreased significantly in the middle range (2 to 6 mg/kg). As main factors of nonlinearity, saturations of solubility, efflux transport in the intestine, and the hepatic uptake of TEL were indicated. In conclusion, this study demonstrated a high possibility of a stable isotope-IV method to characterize complicated pharmacokinetic properties of oral drugs in animals, which can help to consider the future risks in their clinical use.