A Novel Analytical Method for the Simultaneous Estimation of Remogliflozin and Metformin Hydrochloride by UPLC/PDA in Bulk and Formulation Application to the Estimation of Product Traces

Objectives: A selective and novel method has been optimized for the evaluation of remogliflozin and metformin hydrochloride in bulk and in the formulation and cleaning of samples by UPLC-PDA in bulk and formulation and product traces. Materials and Methods: The principle analytes were eluted with phosphate buffer (pH: 4.5): acetonitrile (60:40%, v/v) as the mobile phase using the Spherisorb C18, 5 µm, 4.6 mm x 150 mm analytical column with a 1.0 mL/min flow rate and a 10 µL sample volume at 245 nm in a photodiode array detector. Results: The retention times of remogliflozin and metformin hydrochloride were 3.017 min and 5.011 min with a total run time of 8 min. The curve indicates that the correlation coefficient (r2) was superior with a value of 1.000 in the linear range of 10 ng/mL-100.0 ng/mL for remogliflozin and 50 ng/mL-500.0 ng/mL for metformin hydrochloride. The correlation coefficient (r2) for metformin hydrochloride was found to be 1.000. The lower limits of quantification and detection for remogliflozin and metformin hydrochloride were found to be 10 ng/mL and 50 ng/mL, and 5 ng/mL and 10 ng/mL, respectively. Conclusion: The developed method was validated and applied to the bulk drug estimation and drug formulation and cleaning samples. All the results obtained with this method was accurate and precise.

Method development and validation of almotriptan in human plasma by HPLC tandem mass spectrometry: application to pharmacokinetic study.

A simple, sensitive and selective method has been developed for quantification of Almotriptan (AL) in human plasma using Almotriptan-d(6) (ALD6) as an internal standard. Almotriptan and Almotriptan-d(6) were detected with proton adducts at m/z 336.1→201.1 and 342.2→207.2 in multiple reaction monitoring (MRM) positive mode, respectively. The method was linear over a concentration range of 0.5-150.0 ng/mL. The limit of detection (LOD) and limit of quantification (LOQ) for Almotriptan were 0.2 pg/mL and 0.5 ng/mL, respectively. Liquid-liquid extraction was used followed by MS/MS (ion spray). The method was shown to be precise with an average within-run and between-run variation of 0.68 to 2.78% and 0.57 to 0.86%, respectively. The average within-run and between-run accuracy of the method throughout its linear range was 98.94 to 102.64% and 99.43 to 101.44%, respectively. The mean recovery of drug and internal standard from human plasma was 92.12 ± 4.32% and 89.62 ± 6.32%. It can be applied for clinical and pharmacokinetic studies.

Development and validation of amisulpride in human plasma by HPLC coupled with tandem mass spectrometry and its application to a pharmacokinetic study.

In this study, authors developed a simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantification of Amisulpride in human plasma using Amisulpride-d(5) as an internal standard (IS). Chromatographic separation was performed on Zorbax Bonus-RP C18, 4.6 × 75 mm, 3.5 µm column with an isocratic mobile phase composed of 0.2% formic acid:methanol (35:65 v/v), at a flow-rate of 0.5 mL/min. Amisulpride, Amisulpride-d(5) was detected at m/z 370.1→242.1 and 375.1→242.1. The drug and the IS were extracted by a liquid-liquid extraction method. The method was validated over a linear concentration range of 2.0-2500.0 ng/mL for Amisulpride with a correlation coefficient of (r(2)) ≥ 0.9982. This method demonstrated intra- and inter-day precision within 0.9 to 1.7 and 1.5 to 2.8 % and intra- and inter-day accuracy within 98.3 to 101.5 and 96.0 to 101.0 % for Amisulpride. Amisulpride was found to be stable at 3 freeze-thaw cycles, bench top and auto sampler stability studies. The developed method was successfully applied to a pharmacokinetic study.

LC-ESI-MS/MS method for the quantification of entecavir in human plasma and its application to bioequivalence study.

Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was used for a quantitative estimation of entecavir (EV) in human plasma using lamivudine (LM) as internal standard (IS). The method herein described is simple, sensitive, and specific. Chromatographic separation was performed on XBridge-C18, 4.6 mm × 50 mm, 5-µm column with an isocratic mobile phase composed of 10 mM ammonium hydrogen carbonate (pH 10.5):methanol (85:15 v/v), pumped at 0.3 ml/min. EV and LM were detected using proton adducts at m/z 278.1→152.1 and 230.2→112.0 in multiple reaction monitoring (MRM) positive mode. Solid phase extraction method was employed in the extraction of EV and LM from the biological matrix. This method was validated over a linear concentration range of 50.0-20000.0 pg/ml with a correlation coefficient (r) ≥0.9983. Intra and inter-day precision of EV was found within the range of 1.2-4.2 for EV and 4.4-4.5 for LM. EV was stable throughout three freeze/thaw cycles, bench top and postoperative studies. This method was successfully used in the analysis of plasma samples following oral administration of EV (0.5 mg) in 26 healthy human volunteers.

Method development and validation for naratriptan determination in human plasma by HPLC with tandem mass spectrometry detection, and its application to bioequivalence study / Desenvolvimento de método e validação para determinação de naratriptan em plasma humano por HPLC com detecção de espectrometria de massa em tandem, e sua aplicação ao estudo de bioequivalência

The authors developed a simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of naratriptan (NP) in human plasma using naratriptan-d3 (NPD3) as an internal standard (IS). Chromatographic separation was performed on a Zorbax SB-C18, 75 x 4.6 mm, 3.5 µm column with an isocratic mobile phase composed of 0.1 percent formic acid : acetonitrile (50:50 v/v), at a flow-rate of 0.6 mL/min. NP and NPD3 were detected with proton adducts at m/z 336.5→98.0 and 339.4→101.0 in selected reaction monitoring (SRM) positive mode, respectively. The liquid-liquid extraction method was used to extract the NP and NPD3. This method was validated over a linear concentration range of 0.1-25.0 ng/mL with a correlation coefficient of (r2) > 0.9998. The Intra-day and Interday precision was found to be 1.8 to 3.6 percent, and 2.3 to 2.6 percent, and accuracy to be 101.7- 104.2 percent and 101.8 to 102.9 percent, respectively. NP was found to be stable throughout freeze-thaw (three cycles), bench top and auto sampler stability studies. This method was successfully applied for the analysis of plasma samples following oral administration of NP (2.5 mg) in 31 healthy Indian male human volunteers under fasting conditions.

Os autores desenvolveram um método simples, sensível e específico de cromatografia líquida-espectrometria de massa-tandem (LC-MS/MS) para a quantificação de naratriptan (NP) em plasma humano empregando naratriptan-d3 (NPD3) como padrão interno de referência (IS). A separação cromatográfica foi realizada em coluna Zorbax SB-C18, 75 x 4,6 mm, 3,5 μm com fase móvel isocrática composta por 0,1 por cento ácido fórmico : acetronitrila (50:50 v/v) e taxa de fluxo de 0,6 mL/min. NP e NPD3 foram detectados com adutos de prótons a m/z 336.5→98.0 e 339.4→101.0 in em modo positivo do tipo monitoramento de reação selecionada (SRM), respectivamente. Extração líquido-líquido foi empregada para extrair NP e NPD3, sendo o método validado para uma faixa linear de concentração de 0,1-25,0 ng/mL resultando em coeficiente de correlação (r2) > 0,9998. A variação intra e interdia observada para precisão foi de 1,8 a 3,6 por cento e 2,3 a 2,6 por cento, respectivamente; para exatidão a variação foi de 101,7 a 104,2 por cento e 101,8 a 102,9 por cento, respectivamente. O NP se mostrou estável frente a processos de congelamento-descongelamento (3 ciclos), e estudos de estabilidade de bancada e amostragem automática. O método desenvolvido foi aplicado com sucesso para a análise de amostras de plasma após a administração oral de 2,5 mg de NP em 31 voluntários humanos, de nacionalidade indiana, sexo masculino, sob condições aceleradas.

Method development and validation of montelukast in human plasma by HPLC coupled with ESI-MS/MS: application to a bioequivalence study.

A simple, sensitive, and specific LC-ESIâMS/MS method for quantification of Montelukast (MO) in human plasma using Montelukast-d(6) (MOD6) as an internal standard (IS) is discussed here. Chromatographic separation was performed on YMC-pack pro C(18), 50 x 4.6 mm, S-3 Îm column with an isocratic mobile phase composed of 10mM ammonium formate (pH 4.0):acetonitrile (20:80 v/v), at a flow-rate of 0.8 mL min(â1). MO and MOD6 were detected with proton adducts at m/z 586.2â568.2 and 592.3â574.2 in multiple reaction monitoring (MRM) positive mode respectively. MO and MOD6 were extracted using acetonitrile as precipitating agent. The method was validated over a linear concentration range of 1.0â800.0 ng mL(â1) with correlation coefficient (r(2)) â 0.9996. The intraday precision and accuracy were within 1.91â7.10 and 98.32â99.17. The inter-day precision and accuracy were within 3.42â4.41% and 98.14â99.27% for MO. Both analytes were found to be stable throughout three freeze-thawing cycles, bench top, and autosampler stability studies. This method was utilized successfully for the analysis of plasma samples following oral administration of MO (5 mg) in 31 healthy Indian male human volunteers under fasting conditions.

Quantitative estimation of riluzole in human plasma by LC-ESI-MS/MS and its application to a bioequivalence study.

A novel simple, sensitive, selective, and rapid high-performance liquid chromatography coupled with tandem mass spectrometry method was developed and validated for quantification of riluzole in human plasma. The chromatography was performed by using a Zorbax-SB-C18 (4.6 x 75 mm, 3.5 microm) column , isocratic mobile phase 0.1% formic acid/acetonitrile (10:90 v/v), and an isotope-labeled internal standard (IS), [(13)C,(15)N(2)]riluzole. The extraction of drug and internal standard was performed by liquid-liquid extraction and analyzed by MS in the multiple reaction monitoring (MRM) mode using the respective [M+H](+) ions, m/z 235.0/165.9 for riluzole and m/z 238.1/169.0 for the IS. The calibration curve was linear over the concentration range 0.5-500.0 ng/ml for riluzole in human plasma. The limit of quantification (LOQ) was demonstrated at 0.5 ng/ml. The within-batch and between-batch precision were 0.6-2.3% and 1.4-5.7%, and accuracy was 97.1-101.1% and 98.8-101.2% for riluzole respectively. Drug and IS were eluted within 3.0 min. The validated method was successfully applied in a bioequivalence study of riluzole in human plasma.