HPLC法测定坎地沙坦酯中有关物质和降解产物

目的　研究坎地沙坦酯原料药中有关物质和降解产物的测定方法。方法　采用高效液相色谱法。色谱系统为 :色谱柱KromasllC18柱 ,流动相 0 0 6mol/L醋酸钠 (冰醋酸调节pH4 5 ) 甲醇 (2 0∶80 ) ,检测波长 2 5 5nm。结论　本法可将原料药有关物质和破坏条件下的降解产物与主药有较好的分离度 ,并对合成中间体进行纯度检查 ,适用于原料的质量控制。     

醋酸地塞米松片及其有关物质分析

目的:进一步考察醋酸地塞米松片剂的质量,检测有关物质,防止掺假。方法:采用薄层色谱法和高效液相色谱法,薄层色谱条件,硅胶 G_(F254)板10×20 cm,展开剂二氯甲烷-甲醇(18:2),在254nm 波长下检视。高效液相色谱法 C_(18)反相柱,流动相:甲醇-水(70:30),检测波长在240nm 或254nm,流速0.8mL·min~(-1),r=0.9999。结果:在 TLC 条件下,可检出主成分及有关物质,HPLC 可准确定量主成分,同时检测有关物质。结论:采用薄层色谱法和高效液相色谱法,可测定醋酸地塞米松片及其有关物质,该方法准确灵敏,也可用于药物快速检验。     

HPLC法测定坎地沙坦酯中有关物质和降解产物

目的 研究坎地沙坦酯原料药中有关物质和降解产物的测定方法。方法 采用高效液相色谱法。色谱系统为：色谱柱Kromasll C18柱，流动相0．06mol／L醋酸钠(冰醋酸调节pH4．5)—甲醇(20：80)，检测波长2．55nm。结论 本法可将原料药有关物质和破坏条件下的降解产物与主药有较好的分离度，并对合成中间体进行纯度检查，适用于原料的质量控制。     

奥美沙坦酯中有关物质的HPLC测定

建立了高效液相色谱法测定奥美沙坦酯中的有关物质.采用C18色谱柱,以30mmol/L磷酸二氢钾溶液(用磷酸调至pH 3.5)-甲醇(40:60)为流动相,检测波长256nm.在此条件下奥美沙坦酯与其合成中间体、降解产物分离情况较好.     

HPLC法测定安乃近注射液的有关物质

目的:建立高效液相色谱法测定安乃近注射液中的有关物质。方法:采用C18柱,以甲醇-磷酸盐缓冲液(pH 7.0)(25∶75)为流动相,检测波长为265 nm。结果:安乃近与其降解产物在该色谱条件下能够有效分离。结论:方法简便、专属性强,可用于测定安乃近注射液中有关物质。     

希普林有关物质的检测方法研究

目的:建立希普林的有关物质高效液相色谱检查法。方法:反相高效液相色谱法,用 Diamonsil C_(18)柱(4.6 mm×250mm,5μm),以醋酸-醋酸铵缓冲液(pH 6.0)-甲醇(3:7)为流动相,检测波长为300 nm;正相高效液相色谱法,用 Intersil SIL100A-5柱(4.6 mm×250 mm,5μm),以正己烷-无水乙醇-冰醋酸(80:20:0.01)为流动相,检测波长为300 nm 和263 nm。结果:希普林在反相高效液相色谱分析中发生分解,而在正相高效液相色谱法中性质稳定,满足测定要求。结论:正相高效液相色谱法较反相高效液相色谱法适合检测希普林中的有关物质,方法简便、准确。     

阿莫西林缓释片中有关物质的高效液相色谱法测定

用高效液相色谱法测定阿莫西林缓释片中的有关物质,采用C_(18)色谱柱(4.6×200mm·5μ)为固定相,以磷酸盐缓冲液(pH7.0)-甲醇(80:20)为流动相,检测波长为228nm。该法操作简便,测定结果可靠。     

双嘧达莫片中有关物质测定法方法的研究

目的：建立双嘧达莫片中有关物质的方法。方法：采用高效液相色谱法,色谱柱为Agilent XDB-C₁₈(4.6mm×250mm,5μm),流动相为0.1%磷酸氢二钠溶液(用磷酸调节pH值至4.6)-甲醇(25:75),检测波长为288nm,流速1.0mL.min^_-1。结果:双嘧达莫与其降解产物在该色谱条件下能够有效分离。结论:所建方法简便,专属性强,可以用于双嘧达莫片中有关物质的测定。     

降血脂候选新药SIPI-4884有关物质的HPLC法测定

SIPI-4884是由本室自主研发的降血脂候选新药.本研究以其合成路线中的各中间体及可能的副产物或降解产物为对象,建立了高效液相色谱法检测有关物质.采用C18色谱柱,以四氢呋喃-甲醇-0.02 mol/L乙酸铵缓冲液(用乙酸调至pH4.5)(13∶48∶39)为流动相,检测波长255nm,以检测非手性有关物质.SIPI-4884对映异构体的色谱条件为:CHIRALCEL AS-H色谱柱,流动相为正己烷-乙醇-三氟乙酸(80∶20∶0.1),检测波长255 nm.3批样品的总杂质量都小于1％,其中最大杂质是5-羰基物.     

HPLC法测定尼可刹米中有关物质

建立HPLC法测定尼可刹米中有关物质.采用Diamonsil C18色谱柱,以甲醇-水(30:70)为流动相;检测波长263nm;流速1.0mL·min-1.高效液相色谱法测定尼可刹米中有关物质,降解产物与主峰达到有效分离,样品测定符合规定.该法操作简便,结果准确,专属性强,可用于尼可刹米原料中的有关物质的测定.     

Isolation and characterization of some potential impurities in ropinirole hydrochloride

Three impurities in ropinirole hydrochloride drug substance at levels approximately 0.06-0.15% were detected by reverse-phase high performance liquid chromatography (HPLC). These impurities were isolated from the drug substance. These impurities were analyzed using reverse-phase HPLC. Based on the spectral data (IR, NMR and MS), structures of these impurities were characterized as 4-[2-(propylamino) ethyl]-1,3-dihydro-2H-indol-2-one hydrochloride (impurity-A), 5-[2-(diropylamino) ethyl]-1,4-dihydro-3H-benzoxazin-3-one hydrochloride (impurity-B) and 4-[2-(diropylamino) ethyl]-1H-indol-2,3-dione hydrochloride (impurity-C). Synthesis of these impurities is discussed.     

Investigation and structural elucidation of a process related impurity in candesartan cilexetil by LC/ESI-ITMS and NMR

Four impurities were detected in candesartan cilexetil bulk drug samples by HPLC and LC/MS. These impurities were marked as CDC-I, II, III and IV. One of the impurities CDC-II was unknown and has not been reported previously. An optimized method using liquid chromatography coupled with electrospray ionization ion trap mass spectrometry (LC/ESI-ITMS) in positive ion mode has been developed to carry out structural identification of unknown impurity. Based on mass spectrometric data and synthetic specifics the structure of CDC-II was proposed as 2-ethoxy-1-[[2′-(1-ethyl-1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H-benzimidazole-7-carboxylic acid ethyl ester. The impurity was isolated by semi-preparative HPLC and structure was confirmed by NMR spectroscopy. The plausible mechanism for the formation of impurities is also discussed.     

Structural identification and characterization of potential degradants of zotarolimus on zotarolimus-coated drug-eluting stents

Identification and characterization of unknown zotarolimus impurities on zotarolimus-coated drug-eluting stents is an important aspect of product development since the presence of impurities can have a significant impact on quality and safety of the drug product. Four zotarolimus degradation products have been characterized by LC/UV/PDA, LC/MS, LC/MS/MS and NMR techniques in this work. Zotarolimus drug substance and zotarolimus-coated stents were subjected to degradation under heat, humidity, acid or base conditions. The HPLC separation was achieved on a Zorbax Eclipse XDB-C8 column using gradient elution and UV detection at 278 nm. All four impurities generated through the degradation were initially analyzed by LC/MS and/or LC/MS/MS for structural information. Then the isolation of these degradants was carried out by semi-preparative HPLC method followed by freeze-drying of the collected fractions. Finally the degradants were studied by ¹H and ¹³C NMR spectrometry. Based on LC/MS, ¹H NMR and ¹³C NMR data, the structures of these impurities were proposed and characterized as zotarolimus ring-opened isomer (1), zotarolimus hydrolysis product, 16-O-desmethyl ring-opened isomer (2) and zotarolimus lower fragment (3). Degradants 1, 2 and 3 have been observed on degraded zotarolimus-coated stent products.     

TLC determination of meloxicam in tablets and after acidic and alkaline hydrolysis

A simple and rapid method for separation and determination of meloxicam and its degradation products by thin-layer chromatography with densitometric detection in pharmaceutical preparations was described. The method employed TLC F254 plates as the stationary phase. The solvent system consisted of ethyl acetate : toluene : butylamine (2:2:1, v/v/v). Densitometric analysis was carried out in absorbance mode at wavelength of 297 nm. The method was validated for linearity, precision and accuracy. The limits of detection and determination were 0.96 μg per spot and 2.90 μg per spot, respectively. The drug was degraded in acidic and basic environment, at different temperatures. The degradation products were well resolved from the active substance. The HPLC-MS/MS method for the identification of degradation products of meloxicam (i.e. 5-methylthiazol- 2-ylamine and 5-(dioxide-l(6)-sulfanylidene)-6-methylidenecyclohexa-1,3-diene) was investigated. Because the presented method allows the efficient separation of the drug from some of its degradation products, so it can be used as a stability-indicating analysis.     

LC determination of glimepiride and its related impurities

Five impurities in glimepiride drug substance were detected and quantified using a simple isocratic reverse phase HPLC method. For the identification and characterization purpose these impurities were isolated from a crude reaction mixture of glimepiride using a normal phase HPLC system. Based on the spectroscopic data like NMR, FTIR, UV and MS these impurities were characterized and used as impurity standards for determining the relative response factor during the validation of the proposed isocratic reverse phase HPLC method. The chromatographic separation was achieved on a Phenomenex Luna C8 (2) 100 Å, 5 μm, 250 mm × 4.6 mm using a mobile phase consisting of phosphate buffer (pH 7.0)–acetonitrile–tetrahydrofuran (73:18:09, v/v/v) with UV detection at 228 nm and a flow rate of 1 ml/min. The column temperature was maintained at 35 °C through out the analysis. The method has been validated as per international guidelines on method validation and can be used for the routine quality control analysis of glimepiride as active pharmaceutical ingredient (API).     

Isolation, identification, and synthesis of two oxidative degradation products of olanzapine (LY170053) in solid oral formulations

Two impurities found in both stressed and aged solid-state formulations of olanzapine have been identified as (Z)-1,3-dihydro-4-(4-methyl-1-piperazinyl)-2-(2-oxopropylidene)-2H-1,5-benzodiazepin-2-one (1) and (Z)-1-[1,2-dihydro-4-(4-methyl-1-piperazinyl)-2-thioxo-3H-1,5-benzodiazepin-3-ylidene]propan-2-one (2). The structures indicate that the two impurities are degradation products resulting from oxidation of the thiophene ring of olanzapine. The impurities were isolated by preparative HPLC from a thermally stressed formulation, and characterized by UV, IR, MS, and NMR. A synthetic preparation of compounds 1 and 2 by reaction of olanzapine with the singlet oxygen mimic 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) is presented. The structure of 2 was also determined by single-crystal X-ray diffraction analysis. A degradation pathway for the formation of 1 and 2 is proposed.     

Preparative isolation and structural elucidation of impurities in fluconazole by LC/MS/MS

Three impurities were detected in the LC/MS analysis of fluconazole bulk drug substance. Two of the impurities were unknowns having not been reported previously. Structural assignment of these impurities was carried out by LC/MS/MS using electrospray ionization source and an ion trap mass analyzer. Structural elucidation using nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy was facilitated by newly developed rapid preparative isolation method. These impurities were characterized as 1-(1-H-1,2,4-triazole-1-yl) propane-2,3-diol and Z-2-(2,4-difluorophenyl)-3-(1-H-1,2,4-triazole-1-yl)-2-propen-1-ol. Their formation and synthesis are discussed.     

Characterization and quantitative determination of impurities in piperaquine phosphate by HPLC and LC/MS/MS

Four impurities in piperaquine phosphate bulk drug substance were detected by a newly developed gradient reverse phase high performance liquid chromatographic (HPLC) method. These impurities were identified by LC/MS/MS. The structures of impurities were confirmed by spectroscopic studies (NMR and IR) conducted using synthesized authentic compounds. The synthesized reference samples of the impurity compounds were used for the quantitative HPLC determination. The system suitability of HPLC analysis established the validity of the separation. The method was validated according to ICH guidelines with respect to specificity, precision, accuracy and linearity. Forced degradation studies were also performed for piperaquine phosphate bulk drug samples to demonstrate the stability indicating power of the newly developed HPLC method.     

Identification of new impurities of enalapril maleate on oxidation in the presence of magnesium monoperoxyphthalate

Stress stability testing and forced degradation were used to determine the stability of enalapril maleate (EM) and to find a degradation pathway for the drug. The degradation impurities, formed under different stressed conditions, were investigated by HPLC and UPLC–MS methods. HPLC analysis showed several degradation impurities of which several were already determined, but on oxidation in the presence of magnesium monoperoxyphthalate (MMPP) several impurities of EM were observed which were not yet characterized. The HPLC methods for determination of EM were validated. The linearity of HPLC method was established in the concentration range between 0.5 and 10 μg/mL with correlation coefficient greater than 0.99. The LOD of EM was 0.2 μg/mL and LOQ was 0.5 μg/mL. The validated HPLC method was used to determine the degradation impurities in samples after stress stability testing and forced degradation of EM. In order to identify new degradation impurities of EM after forced degradation UPLC–MS/MSⁿ, Orbitrap has been used. It was found that new impurities are oxidation products: (S)-1-((S)-2-((S)-1-ethoxy-4-(o,m,p-hydroxyphenyl)-1-oxobutan-2-ylamino)propanoyl)pyrrolidine-2-carboxylic acid, (2S)-1-((2S)-2-((2S)-1-ethoxy-4-hydroxy-1-oxo-4-phenylbutan-2-ylamino)propanoyl)pyrrolidine-2-carboxylic acid. (S)-2-(3-phenylpropylamino)-1-(pyrrolidin-1-yl)propan-1-one was identified as a new degradation impurity.     

LC-UV-PDA and LC-MS studies to characterize degradation products of glimepiride

Degradation products of glimepiride formed under different forced conditions have been characterized through LC-UV-PDA and LC-MS studies. Glimepiride was subjected to forced decomposition under the conditions of hydrolysis, oxidation, dry heat and photolysis, in accordance with the ICH guideline Q1A(R2). The reaction solutions were chromatographed on reversed phase C8 (150 mm x 4.6mm i.d., 5 microm) analytical column. In total, five degradation products (I-V) were formed under various conditions. The drug degraded to products II and V under acid and neutral hydrolytic conditions while products I, III and IV were formed under the alkaline conditions. The products II and V were also observed on exposure of drug to peroxide. No additional degradation product was shown up under photolytic conditions. All the products, except I, could be characterized through LC-PDA analyses and study of MS fragmentation pattern in both +ESI and -ESI modes. Product I could not be identified, as it did not ionize under MS conditions. The products II, III and V matched, respectively, to impurity B (glimepiride sulfonamide), impurity J and impurity C (glimepiride urethane) listed in European Pharmacopoeia. The product IV was a new degradation product, characterized as [[4-[2-(N-carbamoyl)aminoethyl]phenyl]sulfonyl]-3-trans-(4-methylcyclohexyl) urea. The degradation pathway of the drug to products II-V is proposed, which is yet unreported.