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Khan M.,Aptuit Laurus Private Ltd | Jayasree K.,Aptuit Laurus Private Ltd | Reddy K.V.S.R.K.,Aptuit Laurus Private Ltd | Dubey P.K.,Jawaharlal Nehru University
Journal of Pharmaceutical and Biomedical Analysis | Year: 2012

A simple and rapid capillary zone electrophoretic method was developed for determining dimethyl sulfate a possible human carcinogen and mutagen and chloroacetyl chloride a potential genotoxic agent at trace levels in pharmaceutical drug substances by indirect photometric detection. A systematic screening of various anionic probes was performed to obtain the best separation conditions and sensitivity. High sensitivities with low quantification and detection levels were achieved for dimethylsulfate and chloroacetyl chloride using a background electrolyte (BGE) containing 5. mM pyridine dicarboxylic acid as the probe ion. The method is specific, precise and accurate for the two genotoxins. The optimized method was validated for specificity, precision, linearity, accuracy and stability in solution. Calibration curves were linear (R> 0.999) for both dimethylsulfate and chloroacetyl chloride in the range LOQ - 300% of nominal concentrations. The CE method was effectively implemented for estimating dimethylsulfate and chloroacetyl chloride in two different active pharmaceutical ingredients (APIs). © 2011 Elsevier B.V.

Khan M.,Aptuit Laurus Private Ltd | Reddy C.N.K.,Aptuit Laurus Private Ltd | Ravindra G.,Aptuit Laurus Private Ltd | Reddy K.V.S.R.K.,Aptuit Laurus Private Ltd | Dubey P.K.,Jawaharlal Nehru University
Journal of Pharmaceutical and Biomedical Analysis | Year: 2012

A series of novel 6-fluoro1,4-dihydro-4-oxo-3-quinoline carboxylic acid dimers were synthesized as potential antibacterial agents from commercially available substituted fluorobenzoic acids. A stability indicating HPLC method was developed to determine these novel fluoroquinolone dimers using a systematic method development approach. Samples were subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation; and analyzed to demonstrate the specificity and stability indicating ability of the developed method. The precision for all four fluoroquinolone dimers was within 2.0% RSD. Calibration curves were linear (LOQ, 150%), with regression coefficients >0.99 for all dimers. The method was conveniently applied for determining purity and assay of these four novel fluoroquinolone dimers. © 2011 Elsevier B.V.

Ravindran J.,University of Texas M. D. Anderson Cancer Center | Subbaraju G.V.,Aptuit Laurus Private Ltd | Ramani M.V.,Aptuit Laurus Private Ltd | Sung B.,University of Texas M. D. Anderson Cancer Center | Aggarwal B.B.,University of Texas M. D. Anderson Cancer Center
Biochemical Pharmacology | Year: 2010

Curcumin, a component of turmeric (Curcuma longa), exhibits anti-inflammatory and anti-proliferative activities through the generation of reactive oxygen species (ROS). Curcumin (diferuloylmethane) contains two hydroxyl, two methoxy and two phenyl groups but how these groups contribute to its activity is poorly understood. We synthesized analogues that varied in inclusion of these groups and compared their activity. We found that bisdemethylcurcumin (BDC) was more potent than curcumin as an anti-inflammatory agent as indicated by suppression of TNF-induced NF-κB activation, more potent as an anti-proliferative agent, and more potent in inducing ROS. Hispolon, which lacks one aromatic unit in relation to curcumin, also exhibited enhanced anti-inflammatory and anti-proliferative activities. When synthetic curcumin (Cur-S) was compared with bisdemethylcurcumin (BDC), hispolon, hispolon methyl ether (HME), dehydroxy hispolon (DH), hydroxy hispolon (HH), methoxy hispolon methyl ether (MHME), and methoxy hispolon (MH), we found that following order of anti-inflammatory activity: BDC=Hispolon>HME>HH>Cur-S>MHME>MH>DH; for anti-proliferative: Hispolon>BDC>MHME>Cur-S>MH>HME=HH>DH; and for prooxidant: BDC>Cur-S=MHME>HH>MH+HME>DH (254-1414 mean fluorescence intensity). Thus, dehydroxy hispolon was least potent for all three activities. Overall the results indicate that the substitution of a hydroxyl group for a methoxy group at the meta positions of the phenyl rings in curcumin significantly enhanced the anti-inflammatory activity, and the removal of phenyl ring at the 7th position of the heptadiene back bone and addition of hydroxyl group significantly increased the anti-proliferative activity of curcumin. © 2010 Elsevier Inc.

Kumar I.V.S.,Aptuit Laurus Private Ltd | Ramanjaneyulu G.S.,Aptuit Laurus Private Ltd | Bindu V.H.,Jawaharlal Nehru Technological University
Letters in Organic Chemistry | Year: 2011

Synthesis of Sildenafil by the O-alkylation of 5-[2-hydroxy-5-(4- methylpiperazin-1-ylsulphonyl)phenyl]-1-methyl-3-n-propyl-1,6-dihydro-7H- pyrazolo-[4,3-d]pyrimidin-7-one 8 proved difficult because concomitant alkylation of the pyrimidine moity also occurred. The selective O-alkylation was carried by DCC assisted decarboxilative etherification of the carbonate 9. © 2011 Bentham Science Publishers.

Nageswari A.,Jawaharlal Nehru University | Nageswari A.,Aptuit Laurus Private Ltd | Krishna Reddy K.V.S.R.,Aptuit Laurus Private Ltd | Mukkanti K.,Jawaharlal Nehru University
Chromatographia | Year: 2012

Formaldehyde has been highlighted as potential genotoxic impurity (GTI). Trace-level quantification of GTIs in drug substances requires sensitive, precise and accurate analytical methodologies for their estimation in drug substances and control. Analysis and estimation of formaldehyde is very challenging due to its properties namely volatility, high polarity, low molecular weight and over and above the absence of chromophore. This article presents a validated HPLC-UV method which is sensitive to quantification of formaldehyde in active pharmaceutical ingredient. As formaldehyde does not possess chromophore, the developed HPLC method involves derivatization with 2,4-dinitrophenylhydrazine. Using this method, the detection and quantitation limits achieved are 0.5 and 1.5 ppm, respectively. The calibration curve of formaldehyde was linear over the concentration range of 1.5-20 ppm. The method was found to be sensitive, precise and accurate and the proposed method has been successfully applied to estimate formaldehyde content in scale-up batches of bulk drug. © 2012 Springer-Verlag.

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