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B. M. Rao et al (2007)  have reported An HPLC Assay Method for Lenalidomide. Chromatographic separation was achieved on an Inertsil ODS-3V column using a mobile phase consisting of a mixture of buffer, acetonitrile and Methanol in the ratio 80:8:12 v/v. Degradation studies were performed on bulk samples of Lenalidomide subjected to 0.5N hydrochloric acid, 0.5N sodiumhydroxide, 10% v/v hydrogenperoxide, heating to 60C and UV light at 254nm. Degradation was observed only under base hydrolysis conditions. The developed LC method gave a mass balance close to 99.5%, proving it to be suitable for stability studies and was validated with respect to linearity, accuracy, precision and robustness.
Liu, Qing MS et al (2008)  have reported that a highly sensitive liquid chromatography/mass spectrometry method for simultaneous quantification of Lenalidomide and flavopiridol in human plasma. Samples were extracted by liquid-liquid extraction with acetonitrile (ACN)-containing internal standard, genistein, followed by evaporation of solvent and reconstitution in 95/5 H2O/ACN. Lenalidomide and Levetiracetam were separated by reversed-phase liquid chromatography on a C-18 column using a gradient of H2O and ACN, each with 0.1% formic acid. Atmospheric pressure chemical ionization in positive ion mode with single reaction monitoring on a triple quadrupole mass spectrometer was applied to detect transitions of Lenalidomide (260.06 > 149.10) and flavopiridol (402.09 > 341.02). Lower limits of quantification of Lenalidomide and flavopiridol were 1 and 0.3 nM, respectively. Recoveries of Lenalidomide and flavopiridol from human plasma ranged from 99% to 116% throughout their linear ranges. Within- and between-run precision and accuracy of replicate samples were all less than 15%. This is the most sensitive analytical method reported to date for both Lenalidomide and flavopiridol.
Nandan Srinivasan Raghu et al (2010)  have reported that degradation studies of highly potent and life threatening human birth defect drug Lenalidomide by HPLC and LC-MS. Lenalidomide drug-excipient from the capsule pharmaceutical dosage form was subjected to different ICH prescribed stress conditions of thermal stress, pH hydrolysis, oxidation and photolysis. The drug was found to be stable only at photolysis and thermal stress, while it was extremely susceptible to other stressing conditions especially it showed extensive degradation under alkali conditions. An acceptable separation was achieved through a multi-step gradient elution using an ACE® C18, 150 4.6 mm i.d, 3 μm, stainless steel analytical column and a mobile phase comprising of 0.01 M phosphate buffer (pH, 2.0 ± 0.1) as mobile phase-A, and a mixture of water and acetonitrile in the ratio of 200:800 (v/v) as mobile phase-B, with a flow rate and detection wavelength being 1.0 mL min-1 and 220 nm respectively. The major degradation products appeared at relative retention times (RRT) of 0.75, 0.86, 0.96, 1.33, 1.52, 1.99, 2.04, 2.62 and 2.66 respectively.
Tanyifor M. Tohnya et al (2004)  have reported that Determination of CC-5013 (Lenalidomide), an analogue of thalidomide, in human plasma by liquid chromatography-mass spectrometry. Sample extraction involved liquid-liquid extraction with acetonitrile/1-chlorobutane (4:1, v/v) solution containing the internal standard, umbelliferone. Separation of the compounds of interest was achieved on a column packed with Waters C18 Nova-Pak material (4 μm particle size; 300 mm - 3.9 mm internal diameter) using acetonitrile, de-ionized water, and glacial acetic acid in ratios of 20:80:0.1 (v/v/v) (pH 3.5) delivered at an isocratic flow rate of 1.00 ml/min. Simultaneous MS detection was performed at m/z 260.3 (CC-5013) and m/z 163.1 (umbelliferone). The calibration curve was fit to a linear response-concentration data over a range of 5-1000 ng/ml using a weighting factor of 1/x. Values for accuracy and precision, obtained from four quality controls analyzed on three different days in replicates of five, ranged from 98 to 106% and from 5.5 to 15.5%, respectively. The method was successfully applied to study the pharmacokinetics of Lenalidomide in a cancer patient receiving the drug as single daily dose.
S. Gananadhamu et al (2009)  have reported that Fluorometric estimation of Lenalidomide in pharmaceutical formulations. Lenalidomide is an immunomodulatory agent with anti-angiogenic and anti-neoplastic properties. Lenalidomide is not official in any pharmacopoeia and there are only a few analytical methods were reported for estimation of Lenalidomide in pharmaceutical formulations such as HPLC and LC-MS. We developed one simple and sensitive fluorometric method for estimation of Lenalidomide in pure state and pharmaceutical formulations by using fluorescamine as a fluorogenic reagent. The fluorescence measurements were performed at an excitation wavelength of 391 nm and an emission wavelength of 499 nm respectively. The proposed method shows the linearity in the concentration range of 0.05 to 8µg/ml with a correlation coefficient of 0.9999. The developed method was validated for specificity, precision and accuracy. This method was applied for estimation of Lenalidomide in some commercially available pharmaceutical formulations and found to be simple, sensitive, reproducible and accurate.
S. Gananadhamu et al (2009)  have reported that new spectrophotometric methods for estimation of Lenalidomide in pharmaceutical formulations. Two sensitive spectrophotometric methods were developed for the estimation of Lenalidomide in pharmaceutical formulations. Method A is based on diazo-coupling reaction with N-(1-napthyl) ethylene diamine dihydrochloride (B.M reagent) to form a stable purple coloured chromogen, which can be estimated at 540 nm. Method B is based on the formation of a coloured condensation product with the aromatic aldehyde namely p-dimethyl amino cinnamaldehyde (PDAC) which shows absorption maximum at 530 nm. Both the proposed methods (Method A and Method B) obey Beer's law in the concentration range of 1 to 5µg/ml. The methods were validated for use in routine quality control of Lenalidomide in pharmaceutical formulations.
Sockalingam Anbazhagan et al (2005)  have reported that Simultaneous quantification of stavudine, lamivudine and nevirapine by UV spectroscopy, reverse phase HPLC and HPTLC in tablets. In the UV multi-component spectral method, SV, LV and NV was quantified at 266, 271 and 315 nm, respectively. In the RP-HPLC method, the drugs were resolved using a mobile phase of 20mM sodium phosphate buffer (containing 8mM1-octanesulphonicacid sodium salt):acetonitrile (4:1, v/v) with pH adjusted to 3.5 using phosphoric acid on a C18-ODS-hypersil (5 µm, 250mm-4.6 mm) column in isocratic mode. The retention time of SV, LV and NV was 2.85, 4.33 and 8.39 min, respectively. In the HPTLC method, the chromatograms were developed using a mobile phase of chloroform:methanol (9:1, v/v) on precoated plate of silica gel 60 F254 and quantified by densitometric absorbance mode at 265 nm. The Rf of SV, LV and NV were 0.21-0.27, 0.62-0.72 and 0.82-0.93, respectively. Recovery values of 99.16-101.89%, percentage relative standard deviation of <0.7 and correlation coefficient (linear dynamic range) of 0.9843-0.9999 shows that the developed methods were accurate and precise. These methods can be employed for the routine analysis of tablets containing SV, LV and NV.
N. Kaul et al (2007)  have reported that The International Conference on Harmonisation guidance in practice: stress degradation studies on lamivudine and development of a validated specific stability-indicating HPTLC assay method. The solvent system consisted of carbon tetrachloride - methanol - chloroform - acetonitrile (7.0: 3.0: 2.0: 1.5, v/v/v/v). Densitometric analysis of lamivudine was carried out in the absorbance mode at 275 nm. This system was found to give compact spots for lamivudine (RF value of 0.36 ± 0.02) following double development of chromatoplates with the same mobile phase. Linearity was found to be in the range of 50 - 1000 ng spot-1 with significantly high value of correlation coefficient. The linear regression analysis data for the calibration plots showed good linear relationship with r2 = 0.9994 ± 0.05 in the working concentration range of 300 ng spot-1 to 1000 ng spot-1. The mean value of slope and intercept were 0.11 ± 0.08 and 10.47 ± 1.21, respectively. The method was validated for precision, robustness and recovery. The limit of detection and quantitation were 15 ng spot-1 and 40 ng spot-1 respectively.
Y. Vander Heyden et al (2010)  have reported that Development and validation of a normal-phase HPTLC method for the simultaneous analysis of lamivudine, stavudine and nevirapine in fixed-dose combination tablets. Separation was performed on silica gel 60F254 plates. The mobile phase is comprised of ethyl acetate, methanol, toluene and concentrated ammonia (38.7:19.4:38.7:3.2 v:v:v:v). Detection wavelength was 254 nm. The Rf values were 0.24±0.03, 0.38±0.04 and 0.69±0.04 (n = 8) for LVD, STV and NVP, respectively. An F-test indicated that calibration graphs were adequately linear at the evaluated concentration ranges. The pooled %RSD for repeatability of the percentage amount recovered for LVD, STV and NVP were found to be 0.62, 0.54, and 0.79, and the pooled %RSD for time-different intermediate precision were 1.66, 1.27 and 1.21. The percentage recoveries for the trueness were 99.2%±1.5 for LVD, 98.6%±1.5 for STV and 99.3%±1.7 for NVP (n = 3). Most factors evaluated in the robustness test were found to have an insignificant effect on the selected responses at 95% confidence level. This method was successfully used to analyze fixed-dose tablets samples of LVD, STV and NVP.
Neeraj Kaul et al (2007)  have reported that Stability-indicating high-performance thin-layer chromatographic determination of zidovudine as the bulk drug and in pharmaceutical dosage forms. The method employs aluminum-backed silica gel 60F 254 HPTLC plates with toluene-carbon tetrachloride-methanol-acetone, 3.5 + 3.5 + 2.0 + 1.0 (v/v), as mobile phase. This system was found to give compact spots (R F 0.41 ± 0.02) for zidovudine. Densitometric analysis of zidovudine was performed in absorbance mode at λ = 270 nm. Response was linearly dependent on amount of zidovudine in the range 100-6000 ng per spot with a significantly high correlation coefficient (r 2 = 0.998 ± 0.53). Linear regression analysis data for the calibration plots showed there was a good linear relationship with r 2 = 0.998 ± 0.0003 in the working concentration range 100 to 1000 ng per spot. The mean values of the slope and intercept were 0.063 ± 0.004 and 39.61 ± 1.09, respectively. The method was validated for precision, robustness, and recovery. The limits of detection and quantitation were, respectively, 20 and 40 ng per spot. Statistical analysis proved the method was repeatable and selective for estimation of the drug.
Girum Habtea et al (2009)  have reported that Simultaneous Separation and Determination of Lamivudine and Zidovudine in Pharmaceutical Formulations Using the HPTLC Method. The method developed was based on HPTLC separation of the two drugs followed by densitometric measurements of spots at 276 and 271 nm for lamivudine and zidovudine, respectively. Separation was carried out on Merck HPTLC silica-gel 60 F254 plates, using toluene/chloroform/methanol (1:6:3 v:v) as the mobile phase. Validation of the method was performed based on The International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) guidelines. Second-order polynomial equations were obtained for the regression line in the ranges of 250-1400 and 250-1700 ng/spot for lamivudine and zidovudine respectively. Correlation coefficient (r) values were 0.9998 for both analytes. In the method precision study, coefficients of variation <2% were obtained, which showed that the proposed method provides acceptable intraday and interday variation. The detection and quantification limits and were 3.06 and 9.28 ng/spot for lamivudine and 3.34 and 10.13 ng/spot for zidovudine, respectively. The low coefficient of variation values indicated the robustness of the method. Statistical manipulation did not show any significant effect of one parameter over the others on the robustness of the method.
Eliangiringa Kaale et al (2010)  have reported that An Interlaboratory Investigation on the Use of High-Performance Thin Layer Chromatography to Perform Assays of Lamivudine-Zidovudine, Metronidazole, Nevirapine, and Quinine Composite Samples. Two laboratories extensively investigated the use of HPTLC to perform assays on lamivudine-zidovudine, metronidazole, nevirapine, and quinine composite samples. To minimize the effects of differences in analysts' technique, the laboratories conducted the study with automatic sample application devices in conjunction with variable-wavelength scanning densitometers to evaluate the plates. The HPTLC procedures used relatively innocuous, inexpensive, and readily available chromatography solvents used in the Kenyon or the Global Pharma Health Fund Minilabs® TLC methods. The use of automatic sample applications in conjunction with variable- wavelength scanning densitometry demonstrated an average repeatability or within-laboratory RSD of 1.90%, with 73% less than 2% and 97% at 2.60% or less, and an average reproducibility or among-laboratory RSD of 2.74%.
Soumya Swaminathan et al (2006)  have reported that A simple and rapid liquid chromatography method for simultaneous determination of zidovudine and nevirapine in plasma. The method involves liquid-liquid extraction with ethyl acetate and using 3-isobutyl 1-methyl xanthine as internal standard. The system requires a C18 column (150mm-4.6mm I.D.) and a mobile phase composed of potassium dihydrogen phosphate (15 mM; pH 7.5) and acetonitrile in the ratio of 80:20 (v/v), UV detection at 260nm.
M. Kumar et al (2010)  have reported that Method development and validation of RP-HPLC method for simultaneous determination of Lamivudine and Zidovudine. Chromatography was carried out on a pre-packed AltimaC18 5μ (150*4.6mm) column using filtered and degassed mixture of Ammonium acetate buffer: Methanol (80:20) as mobile phase at a flow rate of 1.0ml/min and effluent was monitored at 270nm.
T.Sudha et al (2010)  have reported that RP-HPLC Method for the Simultaneous Estimation of Lamivudine and Abacavir Sulphate in Tablet Dosage Form. Lamivudine and Abacavir simultaneously in combined dosage form, separation was performed on a 5μm C18 column having dimensions (150X4.6mmid) in isocratic mode, with mobile phase containing a mixture of methanol: water (70:30, v/v/) was used. The Mobile phase was pumped at a flow rate of 1.4 ml/min and eluents were monitored at 275nm. The selected chromatographic conditions were found to separate Lamivudine (Rt= 2.549 min) and Abacavir (Rt= 3.499 min) having a resolution of 4.13 min.