A stability indicating LC method for felodipine

A stability indicating reversed-phase liquid chromatographic (RP-LC) method was developed for the assay of felodipine as a bulk drug and in pharmaceuticals. The chromatography was performed on a C18 column. Eluents were monitored by UV detection at 238 nm using the mobile phase methanol-potassium dihydrogen orthophosphate (pH 3.5; 0.01 M) (75:25, v/v). The method was statistically validated for linearity, accuracy, precision and specificity. The linearity of felodipine peak area responses was demonstrated within the concentration range of 1-7 microg/ml. The limits of detection and quantitation were 150 and 500 ng/ml, respectively. The method was demonstrated to be precise, accurate and specific with no interference from the tablet excipients and separation of the drug peak from the peaks of the degradation products (oxidative degradation, photodegradation, acid and base degradation). The results indicated that the proposed method could be used in a stability assay.     

A stability indicating LC method for zolmitriptan

A gradient, reversed-phase liquid chromatographic (RP-LC) assay method was developed for the quantitative determination of zolmitriptan, used to treat severe migraine headaches. The developed method is also applicable for the related substances determination in bulk drugs. The chromatographic separation was achieved on a Waters X Terra RP18, 250 mm x 4.6 mm, 5 microm column. The gradient LC method employs solutions A and B as mobile phase. The solution A contains a mixture of phosphate buffer pH 9.85:methanol:acetonitrile (70:20:10, v/v/v) and solution B contains a mixture of phosphate buffer, pH 9.85:acetonitrile (30:70). The flow rate was 1.0 ml/min and the detection wavelength was 225 nm. In the developed HPLC method, the resolution between zolmitriptan and its potential impurities, namely Imp-1, Imp-2 and Imp-3 was found to be greater than 3. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. Considerable degradation was found to occur in alkaline medium and oxidative stress conditions. Degradation product formed during base hydrolysis was found to be Imp-3. The stress samples were assayed against a qualified reference standard and the mass balance was found close to 99.5%. The developed RP-LC method was validated with respect to linearity, accuracy, precision and robustness.     

A validated stability indicating LC method for oxcarbazepine

The present paper describes the development of a stability indicating reversed phase liquid chromatographic (RPLC) method for oxcarbazepine in the presence of its impurities and degradation products generated from forced decomposition studies. The drug substance was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. The degradation of oxcarbazepine was observed under base hydrolysis. The drug was found to be stable to other stress conditions attempted. Successful separation of the drug from the synthetic impurities and degradation product formed under stress conditions was achieved on a C18 column using mixture of aqueous 0.02 M potassium dihydrogen phosphate–acetonitrile–methanol (45:35:20, v/v/v) as mobile phase. The developed HPLC method was validated with respect to linearity, accuracy, precision, specificity and robustness. The developed HPLC method to determine the related substances and assay determination of oxcarbazepine can be used to evaluate the quality of regular production samples. It can be also used to test the stability samples of oxcarbazepine.     

高效液相色谱法测定重酒石酸卡巴拉汀胶囊含量

目的:建立测定重酒石酸卡巴拉汀胶囊含量的高效液相色谱法。方法:选用5C18-MS-Ⅱ色谱柱(4.6 mm×250 mm,5μm);流动相:甲醇-水(90∶10);检测波长:217 nm;流速:1.0 mL.min-1;进样量:20μL;柱温:室温。结果:方法的线性范围为:10.9~163.5μg.mL-1,回归方程为:A=2.829×104C-4.103×104(r=0.9997,n=6);日内精密度RSD为1.6%(n=5),日间精密度为1.2%;回收率在97.2%~98.2%之间,RSD在0.72%~1.2%(n=9)。结论:方法简便灵敏,结果准确可靠,可用于重酒石酸卡巴拉汀胶囊的质量控制。     

HPLC法测定重酒石酸卡巴拉汀片含量

目的:建立HPLC法测定重酒石酸卡巴拉汀片中含量.方法:用C18色谱柱,以磷酸盐缓冲溶液(取磷酸二氢钠1.56 g和辛烷磺酸钠2.16 g,加水1000 mL溶解,用磷酸调pH值至4.0)-乙腈(70:30)为流动相,检测波长220 nm;流速为1 mL·min-1,柱温25℃.结果:卡巴拉汀在6.77～27.07μg·mL-1浓度范围内与其相应的峰面积呈良好的线性关系.回归方程为:Y=1 564.79X-2.862 54(r=0.999 8,n=13).精密度试验RSD为0.22%(n=6),平均回收率分别为100.0%,RSD为0.45%(n=9).结论:所建立的HPLC方法灵敏、准确、重现性好,操作简便,可有效测定重酒石酸卡巴拉汀片的含量.     

Stability indicating LC method for the determination of pipamperone

A high performance liquid chromatographic method for the determination of pipamperone in the presence of one related impurity and its degradation products is described. The method is based on the use of an amide functionalized bonded phase column (LC-ABZ⁺ Plus) and a mobile phase of acetonitrile-tetrahydrofuran-sodium phosphate monobasic (0.05 M, pH 6.5) (16:11:73, v/v/v). All peaks are eluted in <8 min. The method was demonstrated to be precise, accurate and specific. Degradation study showed that the drug is stable in acidic medium while it degrades under basic and oxidative conditions. The results indicated that the proposed method could be used in a stability assay.     

A validated stability indicating ion-pair RP-LC method for zoledronic acid

The present paper describes the development of a stability indicating high performance liquid chromatographic (HPLC) assay method for zoledronic acid in the presence of its impurities and degradation products generated from forced decomposition studies. The drug substance was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. The degradation of zoledronic acid was observed under oxidative stress at higher temperature. The drug was found to be stable in other stress conditions attempted. Successful separation of the drug from the degradation products formed under stress conditions was achieved on a C18 column using a mixture of phosphate buffer that contains 7 mM tetra butyl ammonium hydrogen sulphate, an ion-pairing agent and methanol (95:5) as mobile phase. The developed HPLC method was validated with respect to response function, precision, accuracy, specificity and robustness. The developed HPLC method to determine the related substances and assay determination of zoledronic acid can be used to evaluate the quality of regular production samples. It can be also used to test the stability samples of zoledronic acid.     

Determination of zafirlukast by stability indicating LC and derivative spectrophotometry

Two analytical methods have been developed for the determination of zafirlukast, a novel anti-asthmatic drug: high performance liquid chromatography (HPLC) and derivative spectrophotometry (DS). HPLC with ultraviolet detection at 225 nm is carried out with a Symmetry Shield RP18 column and a mobile phase constituted of acetonitrile and 0.01 M potassium dihydrogen phosphate buffer, adjusted the pH to 3.5 with 0.1 M KOH. The LC method is simple, rapid, selective and stability indicating. Indole was used as internal standard for the purpose of quantification of zafirlukast in HPLC. Spectrophotometry uses the third order derivative of the UV spectrum at 251.1 nm (deltalambda value 2.1 nm) for determination. Both methods were fully validated and a comparison was made. The results confirm that the methods are highly suitable for its intended purpose.     

Spectrophotometric and spectrodensitometric methods for the determination of rivastigmine hydrogen tartrate in presence of its degradation product

Three sensitive, selective and precise stability‐indicating methods for the determination of the anti‐Alzheimer's drug, rivastigmine hydrogen tartrate (RIV) in the presence of its alkaline degradation product (major metabolite, NAP 226‐90) and in pharmaceutical formulation were developed and validated. The first method is a second derivative (D₂) spectrophotometric one, which allows the determination of RIV in the presence of its degradate at 262 nm (corresponding to zero crossing of the degradate) over a concentration range of 50–500 µg/ml with mean percentage recovery 100.18 ± 0.628. The second method is the first derivative of the ratio spectra (DD₁) by measuring the peak amplitude at 272 nm over the same concentration range as (D₂) spectrophotometric method, with mean percentage recovery 99.97 ± 0.641. The third method is a TLC‐densitometric one, where RIV was separated from its degradate on silica gel plates using methanol:butanol:H₂O:ammonia (5:4:1:0.01 v:v:v) as a developing system. This method depends on the quantitative densitometric evaluation of thin layer chromatogram of RIV at 263 nm over a concentration range of 20–160 µg/spot, with mean percentage recovery 100.19 ± 1.344. The selectivity of the proposed methods was tested using laboratory‐prepared mixtures. The proposed methods have been successfully applied to the analysis of RIV in pharmaceutical dosage forms without interference from other dosage form additives and the results were statistically compared with reference method. Copyright © 2010 John Wiley & Sons, Ltd.     

Stability indicating LC method for the estimation of venlafaxine in pharmaceutical formulations

A rapid, selective and stability indicating high performance liquid chromatographic method was developed and validated for the estimation of venlafaxine in pharmaceutical dosage forms. The analysis was done on a Spherisorb C8 (4.6×250 mm, 5 μm) column. The mobile phase consisted of acetonitrile:sodium dihydrogen orthophosphate [0.04 M], pH 6.8 (75:25) at a flow rate of 1.5 ml/min. Detection was carried out at a wavelength of 224 nm. The developed method was found to give good separation between the pure drug and the degraded product. The polynomial regression data for the calibration plots showed good linear relationship in the concentration range of 1–10 μg/ml with r=0.9999. The method was validated for precision, accuracy, ruggedness and recovery. The minimum detectable and minimum quantifiable amounts were found to be 150 and 600 ng/ml, respectively. The drug was stable under basic and oxidative conditions. However, the sample treated with acid showed an additional peak at a retention time of 4.32 min other than the main peak at a retention time of 5.32 min. Statistical analysis proves that the method is reproducible and selective for the estimation of venlafaxine. As the method could effectively separate the drug from the degradation product, it can be employed as a stability indicating one.     

The stability of norepinephrine hydrogen tartrate, epinephrine hydrogen tartrate and isoprenaline sulfate. 29. The stability of drugs and preparations

Stability testing of derivatives of brenzcatechine [norepinephrine hydrogentartrate (1), epinephrine hydrogentartrate (2), isoprenaline sulfate (3)] was carried out by stress investigation storing them at different temperatures. Substances of different charges which had been stored under normal conditions were analyzed. After a period of induction all three substances had been decomposed with a higher velocity. The order of kinetic process could not be determined. The storage life time was calculated by the aid of nonlinear regression. Time limit for storage of 5 years for 1 and 2 were confirmed. We suggest to extend it for 3 to 10 years.     

Trimetazidine: stability indicating RPLC assay method

An accurate, specific and reproducible reversed phase liquid chromatographic method for the determination of trimetazidine hydrochloride in presence of its degradation products is reported. The mobile phase consisted of water-acetonitrile-triethylamine (90:10:0.1, v/v/v) adjusted with o-phosphoric acid to a pH of 3.3. Chromatography was performed using C-18 column at a flow rate of 1.0 ml/min and the drug along with its degraded products was detected at 270 nm. The calibration curve of trimetazidine hydrochloride in methanol was linear in the range 500-3000 ng. The mean value of correlation coefficient, slope and intercept were 0.99859 &# 0.001, 17.7986 &# 0.0709 and 482.56 &# 147.03, respectively. The limits of detection and quantitation were 5 and 20 ng, respectively. The recovery of trimetazidine hydrochloride was about 99-100%. This method was utilized to analyze trimetazidine hydrochloride from conventional tablets and controlled release pellets in the presence of commonly used excipients.     

Development and validation of a stability indicating LC method for the assay and related substances determination of Exemestane, an aromatase inhibitor

A selective stability indicating HPLC method was developed and validated for quantification of impurities (process related and degradants) and assay determination of Exemestane. Stability indicating power of the method was established by forced degradation experiments and mass balance study. The chromatographic separation was achieved with Hypersil BDS-C-18 using gradient elution. The developed method is validated for parameters like accuracy, linearity, LOD, LOQ, ruggedness. Box–Behnken experimental design was applied to check the robustness of the method.     

A stability indicating HPLC method for the determination of clobazam and its basic degradation product characterization

Background

Clobazam is used for the treatment of different types of seizure and epilepsy. The present research is undertaken to study the systematic forced degradation of clobazam and to identify its main degradation product under basic conditions.

Methods

The degradation of clobazam was studied under different conditions. Clobazam and its degradation products were separated using a Nova-Pak C18 column and a mixture of KH₂PO₄ 50 mM (pH 8.5) and acetonitrile (50:50, v/v) as the mobile phase with UV detection at 230 nm.

Results

The within-day and between-day precision values in the calibration range of 0.1-20 μg/ml were within 0.5-1.5%. Clobazam was relatively stable in solid from under exposure to visible and UV light and also heat. The clobazam aqueous solution of clobazam was more labile under exposure to visible and UV light. The bulk drug was significantly degraded under exposure to 2 M HCl, 0.1 M NaOH or 3% H₂O₂. Using the tablet powder, higher degradation rates were observed under different stress conditions. The main degradation product of clobazam under basic condition was subsequently characterized.

Conclusion

The developed method could be used for the determination of clobazam in the presence of its degradation products with acceptable precision and accuracy. The applicability of the proposed method was evaluated in commercial dosage forms analysis.     

异硫氰酸苯甲酰酯稳定性指示性气相分析方法开发和验证

目的:建立异硫氰酸苯甲酰酯稳定性指示性气相分析方法.方法:气相色谱柱DB-1(30m×0.25mm×0.25μm);载气:氦气;检测器:氢焰离子化检测器;起始柱温为100℃,维持1.3min,每分钟15℃的速率升温至200℃,然后以每分钟5℃的速率升温至240℃,再以每分钟10℃的速率升温至300℃,维持6min;进样口温度:200℃;检测器温度:300℃;柱流量:1.0mUmin;进样量:1μL.结果:专属性、线性、定量限、检测限、精密度、溶液稳定性、准确度经验证,结果均良好.结论:本法可用于异硫氰酸苯甲酰酯的初步稳定性研究.     

A validated LC method for imatinib mesylate

An isocratic reversed-phase liquid chromatography method with UV detection has been developed for the purity evaluation of imatinib mesylate in bulk drug. The method is selective and is capable of detecting all process intermediates and other related compounds, which may be present at trace levels in the drug substance. The method was validated on a Symmetry Shield RP18 analytical column (150×4.6 mm, 5 μm), mobile phase consisting of 30 mM sodium octane sulphonic acid in 10 mM aqueous KH₂PO₄ (pH 2.5 with H₃PO₄): MeOH in the ratio of 42:58 v/v. The flow rate was set at 1.0 ml/min and the column was maintained at room temperature. The injection volume was set to 10 μl and the detector was set at a wavelength of 237 nm. The method was validated in terms of system precision, method precision, linearity, accuracy, limit of detection and limit of quantification.     

Development and validation of a specific stability indicating high performance liquid chromatographic method for rizatriptan benzoate

A gradient, reversed-phase liquid chromatographic (RP-LC) method was developed for the quantitative determination of rizatriptan benzoate, used to treat relieves migraine headache symptoms. The developed method can be also employed for the related substance determination in bulk samples. Forced degradation studies were performed on bulk sample of rizatriptan benzoate using acid (0.5 N hydrochloric acid), base (0.1 N sodium hydroxide), oxidation (3.0% hydrogen peroxide), water hydrolysis, heat (60 degrees C) and photolytic degradation. Mild degradation of the drug substance was observed in base hydrolysis and considerable degradation observed during oxidative stress. The chromatographic method was fine tuned using the samples generated from forced degradation studies. Good resolution between the peaks corresponds to degradation products and the analyte was achieved on Agilent Zorbax SB-CN (250 mm x 4.6 mm, 5 microm) column. The mobile phase consists of a mixture of aqueous potassium di hydrogen ortho phosphate (pH 3.4), acetonitrile and methanol. The stress sample solutions were assayed against the qualified reference standard of rizatriptan benzoate and the mass balance in each case was close to 99.7% indicating that the developed method is stability indicating. Validation of the developed method was carried out as per ICH requirements.     

Development and validation of a stability indicating RP-UPLC method for determination of quetiapine in pharmaceutical dosage form

The present work reports a stability indicating reversed phase ultra performance liquid chromatography (RP-UPLC) method for the quantitative determination of quetiapine in pharmaceutical dosage form. The chromatographic separation is performed on an Agilent Eclipse Plus C18, RRHD 1.8 μm (50 mm x 2.1 mm) column using gradient elution. The optimized mobile phase consists of 0.1 % aqueous triethylamine (pH 7.2) as a solvent-A and 80:20 v/v mixture of acetonitrile and methanol as solvent-B. The eluted compounds are monitored at 252 nm wavelength using a UV detector. The developed method separates quetiapine from its five impurities/degradation products within a run time of 5 min. Stability indicating capability of the developed method is established by analyzing forced degradation samples in which the spectral purity of quetiapine is ascertained along with the separation of degradation products from analyte peak. The developed RP-UPLC method is validated as per International Conference on Harmonization (ICH) guidelines with respect to system suitability, specificity, precision, accuracy, linearity, robustness and filter compatibility.