Potentially mutagenic impurities: Analysis of structural classes and carcinogenic potencies of chemical intermediates in pharmaceutical syntheses supports alternative methods to the default TTC for calculating safe levels of impurities

Potentially mutagenic impurities in new pharmaceuticals are controlled to levels with negligible risk, the TTC (threshold of toxicological concern, 1.5 μg/day for a lifetime). The TTC was based on the more potent rodent carcinogens, excluding the highly potent “cohort of concern” (COC; for mutagenic carcinogens these are N-nitroso, Aflatoxin-like, and azoxy structures). We compared molecules with DEREK “structural alerts” for mutagenicity used in drug syntheses with the mutagenic carcinogens in the Gold Carcinogenicity Potency Database. Data from 108 diverse synthetic routes from 13 companies confirm that many “alerting” or mutagenic chemicals are in structural classes with lower carcinogenic potency than those used to derive the TTC. Acceptable daily intakes can be established that are higher than the default TTC for many structural classes (e.g., mono-functional alkyl halides and certain aromatic amines). Examples of ADIs for lifetime and shorter-term exposure are given for chemicals of various potencies. The percentage of chemicals with DEREK alerts that proved mutagenic in the Ames test ranged from 36% to 83%, depending on structural class, demonstrating that such SAR analysis to “flag” potential mutagens is conservative. We also note that aromatic azoxy compounds need not be classed as COC, which was based on alkyl azoxy chemicals.     

同时测定乳香中杂质和挥发油含量

建立同时测定乳香中挥发油和杂质含量的方法。方法 以能将乳香中杂质以外的部分全部溶解为目标,对提取溶剂数量和种类进行考察。同时,以杂质以外的部分全部溶解所需时间为指标,对比超声提取和回流提取,确定最佳溶剂、溶剂用量和回流时间。通过溶剂种类、溶剂用量及提取时间的考察,确定能将乳香中除树皮等杂质以外的部分全部溶解的方法。结果 单纯一种溶剂,不能将乳香中杂质以外的部分全部溶解。建立的挥发油和杂质测定方法为：取一定量乳香,加入水,采用水蒸气蒸馏法提取挥发油,滤过,药渣再加入乳香量1.25倍的丙酮,回流提取5min,滤过,不溶残渣即为杂质。收集的11个批次乳香及制乳香中挥发油含量范围为1.25～4.24%,杂质为0.75～2.4%。乳香挥发油含量比其制品制乳香高,杂质含量无明显差异。结论 建立了一种同时测定乳香与制乳香中挥发油和杂质含量的方法,为质量标准的制订提供了参考。     

Analytical Method Capable of Quantifying Eight Nitrosamine Impurities from Five Different Commercially Available Metformin Formulations with Glipizide,Glibenclamide, Gliclazide,Evogliptin, and Glimepiride by Ultra High Performance Liquid Chromatography Tripple Quadrupole Mass Spectrometry

Metformin and its combinations are widely used to treat type 2 diabetes. The drugs commonly used in combination with Metformin are Glipizide, Glibenclamide, Gliclazide, Evogliptin, and Glimepiride. Combination therapy is preferred over monotherapy of Metformin in most diabetics. About eighteen pharmaceutical manufacturers have lately recalled metformin formulation batches from the U.S. market due to N-nitrosodimethylamine (NDMA) impurities based on the food and drug administration (USFDA) guideline “Control of Nitrosamine in Human Drugs.” European Medicines Agency (EMA) and Health Canada have also established guidelines for nitrosamine impurities. Nitrosamines are well-known mutagenic impurities and probable human carcinogens found in pharmaceutical formulations. Thus, global regulatory agencies require pharmaceutical and formulation manufacturers to complete risk assessments for nitrosamine impurities for patient safety. Therefore, drug manufacturers must develop analytical techniques for monitoring trace nitrosamine impurities. Quantifying nitrosamine impurities in formulations requires modern equipment like LC-MS/MS and great intellect. The present study intends to give a single pre-packaged LC-MS/MS method parameters, including liquid chromatography and triple quadrupole mass spectrometer configuration. This method could quantify eight nitrosamine impurities from five different Metformin combinations (Metformin with Glipizide, Glibenclamide, Gliclazide, Evogliptin, and Glimepiride). The atmospheric pressure chemical ionisation (APCI) was used as an ionisation source, and the mass spectrometer was set to multiple reaction monitoring (MRM) mode for all eight nitrosamine impurities. A unified pre-packaged analytical setup allows analytical chemists to develop a reliable, sensitive, robust, and precise method for quantifying eight nitrosamine impurities from five different Metformin formulations of varying manufacturers. This analytical method saves time, money, and the environment using fewer pharmaceutical chemicals.     

LC-HR-MS/MS法鉴定头孢丙烯干混悬剂中的未知杂质

目的:检测头孢丙烯干混悬剂中的未知杂质,并对其进行结构鉴定。方法:采用高效液相色谱-串联高分辨质谱法检测并鉴定头孢丙烯干混悬剂中的未知杂质。色谱柱为Thermo HyPURITYTMC18,流动相为乙腈-0.013%甲酸水溶液(梯度洗脱),检测波长为230 nm,流速为1.0 m L/min,柱温为40℃,进样量为20μL;以电喷雾离子源行正离子全扫描,扫描范围为质荷比(m/z)100~1500,喷雾电压为3.8 kV,金属毛细管温度为320℃,鞘气压力为60 Arb,辅助气压力为10 Arb,喷雾温度为280℃。结果:在该色谱条件下,杂质K的检测限为0.202μg/mL,精密度、重复性试验的RSD均小于4%。杂质K附近发现3个未知杂质,且互为异构体,离子保留时间为17.83~19.31 min,二级母离子均为m/z 436.1500[M+H]+,可能为头孢丙烯开环、脱水后的产物。结论:本方法检测出头孢丙烯干混悬剂中杂质K附近的3个未知杂质。     

Gradient high performance liquid chromatography method for simultaneous determination of ilaprazole and its related impurities in commercial tablets

A methodology (HPLC) proposed in this paper for simultaneously quantitative determination of ilaprazole and its related impurities in commercial tablets was developed and validated. The chromatographic separation was carried out by gradient elution using an Agilent C₈ column (4.6 mm × 250 mm, 5 μm) which was maintained at 25 °C. The mobile phase composed of solvent A (methanol) and solvent B (solution consisting 0.02 mmol/l monopotassium phosphate and 0.025 mmol/l sodium hydroxide) was at a flow rate of 1.0 ml/min. The samples were detected and quantified at 237 nm using an ultraviolet absorbance detector. Calibration curves of all analytes from 0.5 to 3.5 μg/ml were good linearity (r ≥ 0.9990) and recovery was greater than 99.5% for each analyte. The lower limit of detection (LLOD) and quantification (LOQ) of this analytical method were 10 ng/ml and 25 ng/ml for all impurities, respectively. The stress studies indicated that the degradation products could not interfere with the detection of ilaprazole and its related impurities and the assay can thus be considered stability-indicating. The method precisions were in the range of 0.41–1.21 while the instrument precisions were in the range of 0.38–0.95 in terms of peak area RSD% for all impurities, respectively. This method is considered stability-indicating and is applicable for accurate and simultaneous measuring of the ilaprazole and its related impurities in commercial enteric-coated tablets.     

Influence of elemental impurities in aluminum hydroxide adjuvant on the stability of inactivated Japanese Encephalitis vaccine,IXIARO®

Aluminum hydroxide is a critical raw material in the production of many vaccines. It is used as an adjuvant in the formulation of the final bulk vaccine, and for this it must meet the specifications of the European Pharmacopeia Monograph. We investigated whether vaccine stability was affected by the presence of trace amounts of elemental impurities in commercially available aluminum hydroxide. The content of residual elemental impurities in commercially available aluminum hydroxide was determined by selective and sensitive inductively coupled-plasma mass spectrometry and inductively coupled plasma atomic emission spectroscopy. We found significant differences between different suppliers, but also between different lots from the same supplier. Inactivated Japanese encephalitis vaccine, IXIARO^®, was used to study the effect of residual metals in aluminum hydroxide on antigen stability. We propose that antigen degradation occurred via a pathway involving the metal-catalyzed, auto-oxidation of a process-related impurity (sulfite). Thus, sulfite auto-oxidation resulted in antigen degradation when residual Cu was present at elevated concentrations in aluminum hydroxide.     

气相色谱串联质谱法测定二甲双胍格列本脲胶囊(Ⅱ)中N-亚硝基二甲胺的含量

目的:建立了二甲双胍格列本脲胶囊(Ⅱ)中基因毒性杂质N-亚硝基二甲胺(NDMA)的测定方法。方法:采用气相色谱-三重四级杆质谱仪,以多反应监测模式(MRM)进行测定,按外标法定量。仪器条件:EI源温度:230℃;电子能量:70 eV;碰撞气:高纯氮气,碰撞气流速:1.5 mL/min。载气:高纯氦气,载气流速为1.0 mL/min。结果:NDMA在0.243~48.626 ng/mL的浓度范围内呈良好的线性相关,相关系数(R²)大于0.9997,方法检出限均为0.005μg/g,定量限为0.01μg/g,平均回收率为92.41%~101.02%(n=9),RSD为2.4%,重复性试验RSD(n=6)为3.0%,NDMA在定量限浓度及限度浓度的精密度试验RSD(n=6)分别为4.2%和3.2%。结论:方法适合用于二甲双胍格列本脲胶囊(Ⅱ)中基因毒性杂质NDMA的检测。     

Validated stability-indicating HPLC method for the determination of pridinol mesylate. Kinetics study of its degradation in acid medium

The stability of pridinol mesylate (PRI) was investigated under different stress conditions, including hydrolytic, oxidative, photolytic and thermal, as recommended by the ICH guidelines. Relevant degradation was found to take place under acidic (0.1N HCl) and photolytic (visible and long-wavelength UV-light) conditions, both yielding the product resulting from water elimination (ELI), while submission to an oxidizing environment gave the N-oxidation derivative (NOX). The standards of these degradation products were synthesized and characterized by IR, (1)H and (13)C NMR spectroscopy. A simple, sensitive and specific HPLC method was developed for the quantification of PRI, ELI and NOX in bulk drug, and the conditions were optimized by means of a statistical design strategy. The separation employs a C(18) column and a 51:9:40 (v/v/v) mixture of MeOH, 2-propanol and potassium phosphate solution (50mM, pH 6.0), as mobile phase, delivered at 1.0 ml min(-1); the analytes were detected and quantified at 220 nm. The method was validated, demonstrating to be accurate and precise (repeatability and intermediate precision levels) within the corresponding linear ranges of PRI (0.1-1.5 mg ml(-1); r=0.9983, n=18) and both impurities (0.1-1.3% relative to PRI, r=0.9996 and 0.9995 for ELI and NOX, respectively, n=18). Robustness against small modifications of pH and percentage of the aqueous mobile phase was ascertained and the limits of quantification of the analytes were also determined (0.4 and 0.5 microg ml(-1); 0.04% and 0.05% relative to PRI for ELI and NOX, respectively). Peak purity indices (>0.9997), obtained with the aid of diode-array detection, and satisfactory resolution (R(s)>2.0) between PRI and its impurities established the specificity of the determination, all these results proving the stability-indicating capability of the method. The kinetics of the degradation of PRI in acid medium was also studied, determining that this is a first-order process with regards to drug concentration, with an activation energy of 25.5 Kcal mol(-1) and a t(1/2)=10,830 h, in 0.1N HCl at 38 degrees C.     

A validated reversed phase HPLC method for the determination of process-related impurities in almotriptan malate API

An isocratic reversed phase liquid chromatographic (RP-LC) method has been developed and subsequently validated for the determination of almotriptan malate and its process-related impurities. Separation was achieved with a Phenomenex, Gemini, C-18 column and sodium phosphate buffer (pH adjusted to 7.6): acetonitrile (80:20, v/v) as eluent, at a flow rate of 1.5 mL/min. UV detection was performed at 227 nm. The method is simple, rapid, selective, accurate and stability indicating. The described method is linear over a range of LOQ, 1.5 ug/mL (150% of the specification limit) for all the process-related impurities. The method precision for the determination of related compounds was below 1.0% R.S.D. The accuracy of the method demonstrated at 4 levels in the range of 25-150% of the specification limit and the recovery of impurities were found to be in the range of 96-102%. The method is useful in the quality control of bulk manufacturing.     

HPLC测定奥格列汀中基因毒性杂质残留量

目的 建立奥格列汀原料药中基因毒性杂质的HPLC测定方法。方法 采用Zorbax SB-C₁₈色谱柱（250 mm×4.6 mm,5μm）,进样量：20 μl;流动相为0.1%乙酸水-乙腈（65：35）;流速为1mL·min^-1;紫外检测器,检测波长为220 nm;柱温为25℃,色谱乙腈为溶剂。结果 该方法专属性良好,测得苯磺酸异丙酯在4~60 μg·mL^-1内线性关系良好,平均回收率为98.56%（n=9,RSD=3.78%）,溶液在8 h内稳定。结论 该法操作简便,重复性好,结果准确可靠,可用于奥格列汀原料药中基因毒性杂质的测定。