Scientific Papers by Muhammad Wahajuddin
Tamoxifen is used in clinical practice for breast cancer patients and to prevent osteoporosis. Re... more Tamoxifen is used in clinical practice for breast cancer patients and to prevent osteoporosis. Red clover (Trifolium pratense) preparations are consumed worldwide as dietary supplements for relieving postmenopausal symptoms. In the present study we investigated the possible herb-drug interaction between red clover and tamoxifen in rats. 15 days pre-treatment with red clover did not alter the tamoxifen and its active metabolite 4-hydroxytamoxifen pharmacokinetics significantly (p > 0.05). Therefore the therapeutic efficacy of the tamoxifen may not be compromised by the co-administration with red clover. Tamoxifen metabolism is primarily mediated by CYP2D6, CYP3A4 with minor contribution from CYP2C9, CYP2E1 and CYP1A2 isoforms. Although, red clover pre-treatment significantly (p < 0.05) decreased the mRNA expression and activity of CYP3a2, no effect on CYP2d4 and increased expression and activity of CYP2c11 could be the plausible reasons for lack of effect on tamoxifen and its metabolite pharmacokinetics in rats. CYP1a1 and CYP2b2 mRNA expression and activity were also significantly reduced by red clover. To extend the clinical utility of the present study, effect of red clover extract on major CYPs using human liver microsomes and HepG2 cell lines were also determined. Similar finding were observed in the human liver preparations as in rats.
Papers by Muhammad Wahajuddin
Journal of Analytical Toxicology, 2016
United States Environmental Protection Agency has recommended estimating pyrethroids&amp;amp;... more United States Environmental Protection Agency has recommended estimating pyrethroids&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8-2,000 ng/mL with correlation coefficients of ≥0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC-MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity.
Toxicology and applied pharmacology, Jan 3, 2016
The drug, theophylline is frequently used as an additive to medications for people suffering from... more The drug, theophylline is frequently used as an additive to medications for people suffering from chronic obstructive pulmonary diseases (COPD). We studied the effect of theophylline in bone cells, skeleton and parameters related to systemic calcium homeostasis. Theophylline induced osteoblast apoptosis by increasing reactive oxygen species production that was caused by increased cAMP production. Bone marrow levels of theophylline were higher than its serum levels, indicating skeletal accumulation of this drug. When adult Sprague-Dawley rats were treated with theophylline, bone regeneration at fracture site was diminished compared with control. Theophylline treatment resulted in a time-dependent (at 4- and 8weeks) bone loss. At 8weeks, a significant loss of bone mass and deterioration of microarchitecture occurred and the severity was comparable to methylprednisone. Theophylline caused formation of hypomineralized osteoid and increased osteoclast number and surface. Serum bone resor...
Journal of Pharmaceutical and Biomedical Analysis, 2016
The concepts, importance, and application of bioanalytical method validation have been discussed ... more The concepts, importance, and application of bioanalytical method validation have been discussed for a long time and validation of bioanalytical methods is widely accepted as pivotal before they are taken into routine use. United States Food and Drug Administration (USFDA) guidelines issued in 2001 have been referred for every guideline released ever since; may it be European Medical Agency (EMA) Europe, National Health Surveillance Agency (ANVISA) Brazil, Ministry of Health and Labour Welfare (MHLW) Japan or any other guideline in reference to bioanalytical method validation. After 12 years, USFDA released its new draft guideline for comments in 2013, which covers the latest parameters or topics encountered in bioanalytical method validation and approached towards the harmonization of bioanalytical method validation across the globe. Even though the regulatory agencies have general agreement, significant variations exist in acceptance criteria and methodology. The present review highlights the variations, similarities and comparison between bioanalytical method validation guidelines issued by major regulatory authorities worldwide. Additionally, other evaluation parameters such as matrix effect, incurred sample reanalysis including other stability aspects have been discussed to provide an ease of access for designing a bioanalytical method and its validation complying with the majority of drug authority guidelines.
Scientific reports, 2016
A simple, sensitive and high throughput LC-MS/MS method was developed and validated for quantific... more A simple, sensitive and high throughput LC-MS/MS method was developed and validated for quantification of fipronil, fipronil sulfone and fipronil desulfinyl in rat and human dried blood spots (DBS). DBS samples were prepared by spiking 10 μl blood on DMPK-C cards followed by drying at room temperature. The whole blood spots were then punched from the card and extracted using acetonitrile. The total chromatographic run time of the method was only 2 min. The lower limit of quantification of the method was 0.1 ng/ml for all the analytes. The method was successfully applied to determine fipronil desulfinyl in DBS samples obtained from its toxicokinetic study in rats following intravenous dose (1 mg/kg). In conclusion, the proposed DBS methodology has significant potential in toxicokinetics and biomonitoring studies of environmental toxicants. This microvolume DBS technique will be an ideal tool for biomonitoring studies, particularly in paediatric population. Small volume requirements, ...
Scientific Reports, 2015
The pharmacokinetic compatibility of short-acting CDRI candidate antimalarial trioxane derivative... more The pharmacokinetic compatibility of short-acting CDRI candidate antimalarial trioxane derivative, 99-411, was tested with long-acting prescription antimalarials, lumefantrine and piperaquine. LC-ESI-MS/MS methods were validated for simultaneous bioanalysis of lumefantrine and 99-411 and of piperaquine and 99-411 combinations. The interaction studies were performed in rats using these validated methods. The total systemic exposure of 99-411 increased when administered with either lumefantrine or piperaquine. However, co-administration of 99-411 significantly decreased the systemic exposure of piperaquine by half-fold while it had no effect on the kinetics of lumefantrine. 99-411, thus, seemed to be a good alternative to artemisinin derivatives for combination treatment with lumefantrine. To explore the reason for increased plasma levels of 99-411, an in situ permeability study was performed by co-perfusing lumefantrine and 99-411. In presence of lumefantrine, the absorption of 99-411 was significantly increased by 1.37 times than when given alone. Lumefantrine did not affect the metabolism of 99-411 when tested in vitro in human liver microsomes. Additionally, ATPase assay suggest that 99-411 was a substrate of human P-gp, thus, indicating the probability of interaction at the absorption level in humans as well.
Toxicology letters, Jan 13, 2015
Formononetin (FMN) and Biochanin A (BCA) are the principal isoflavones present in commercially av... more Formononetin (FMN) and Biochanin A (BCA) are the principal isoflavones present in commercially available extracts of red clover that are widely been consumed for various health benefits. We investigated the in vitro effects of FMN and BCA on catalytic activity of human/rat cytochrome P450 enzymes to assess the drug interaction potential of red clover. IC50 and Ki values of FMN and BCA for CYPs were determined in human/rat liver microsomes. FMN and BCA showed concentration-dependent inhibition of CYP1A2 activity with IC50 values of 13.42 and 24.98μM in human liver microsomes and 38.57 and 11.86μM in rat liver microsomes, respectively. The mode of inhibition of human CYP1A2 by FMN was found to be competitive with apparent Ki value of 10.13±1.96μM. FMN also inhibited human CYP2D6. BCA exerted moderately inhibitory effects on human CYP2C9. The predicted in vivo inhibition for CYP1A2 was insignificant (R value < 1.1) at hepatic level while at intestinal level, it was significant (R va...
RSC Adv., 2015
An efficient, mild and cost-effective method has been developed utilizing CuBr with N-methylmorph... more An efficient, mild and cost-effective method has been developed utilizing CuBr with N-methylmorpholine N-oxide (NMO/NMMO) for the oxidative coupling of anilines to access symmetrical and unsymmetrical azo compounds in high yield. The reactivity was found to be governed by electronic and steric factors of anilines.
Journal of Chromatography B, 2015
Medicarpin is the active phytoalexin found in the stem bark of Butea monosperma having potent ost... more Medicarpin is the active phytoalexin found in the stem bark of Butea monosperma having potent osteogenic activity. An LC-ESI-MS/MS was developed and validated for quantification of medicarpin in rat plasma using liquid-liquid extraction technique and diethyl ether as the extraction solvent. Medicarpin was separated on RP18 column (4.6mm×50mm, 5.0μm) using methanol and 10mM ammonium acetate (pH 4.0) in the ratio of 80:20 (v/v) as mobile phase. The method was linear within the concentration range of 1-500ng/mL and its sensitivity was 1ng/mL. The precision value for intra- and inter-day assays and stability assays was within 0.88-14.22% while the accuracy ranged between 87.46-116.0% at all four QC levels. The validated method was successfully applied to study the preclinical pharmacokinetics of medicarpin in rats. Medicarpin showed multiple peak phenomenon upon oral administration. Its oral bioavailability was 17.43%. It was found to be a rapidly absorbed (Tmax=15min), 81.61% protein bound and pH stable compound. The present study provides important information regarding preliminary pharmacokinetics of medicarpin for its further exploration as a potential therapeutic agent.
Bioanalysis, 2015
Tamoxifen and centchroman are two non-steroidal, selective estrogen receptors modulators, intende... more Tamoxifen and centchroman are two non-steroidal, selective estrogen receptors modulators, intended for long term therapy in the woman. Because of their wide spread use, there is a possibility of co-prescription of these agents. We studied the probable pharmacokinetic interaction between these agents in breast cancer model rats. A simple, sensitive and rapid LC-ESI-MS/MS method was developed and validated for the simultaneous determination of tamoxifen, centchroman and their active metabolites. The method was linear over a range of 0.2-200 ng/ml. All validation parameters met the acceptance criteria according to regulatory guidelines. LC-MS/MS method for determination of tamoxifen, centchroman and their metabolites was developed and validated. Results show the potential of drug-drug interaction upon co-administration these two marketed drugs.
Drug Testing and Analysis, 2015
Malaria Journal, 2015
Lumefantrine is the mainstay of anti-malarial combination therapy in most endemic countries prese... more Lumefantrine is the mainstay of anti-malarial combination therapy in most endemic countries presently. However, it cannot be used alone owing to its long onset time of action. CDRI 97-78 is a promising trioxane-derivative anti-malarial candidate that is currently being investigated as a substitute for artemisinin derivatives owing to their emerging resistance.
Phytochemistry Reviews, 2015
Isoflavonoids are the biologically active secondary metabolites of plants that are being used for... more Isoflavonoids are the biologically active secondary metabolites of plants that are being used for several health promoting and restoring effects mediated through different pathways. Isoflavonoids are structurally similar to estrogens due to which also known as phytoestrogens and have shown potent estrogenic and anti-estrogenic activity. Association with large biological activity lead to the need of rapid, sensitive and precise quantitation of different isoflavonoids in different plant extracts, food materials and biological matrices as the biological activities mainly depends on the quantities and nature of isoflavonoids present in them. The characterisation, standardisation and quantification of herbal extracts or food products require techniques that are highly selective, sensitive and also provide mass measurement precisions and structural information. Liquid chromatography with tandem mass spectroscopy has made it possible to analyse and characterize several constituents and their metabolites in a single run along with high selectivity and sensitivity. In this review, we have summarised the application of LC-MS/MS for the identification and quantification of isoflavonoids reported for various plant extracts and food products along with their general extraction procedures and factors affecting extraction providing a view towards the conditions used for their analysis. The most suitable and widely acceptable extraction solvent system for the isoflavonoids is methanol or ethanol in combination with water ranging from 40 to 60 % organic solvent based on the type of tissues and the isoflavonoids to be extracted by different extraction techniques. ESI ionization with Q-TOF MS was the most useful detection system for the characterisation and quantification of the diverse isoflavonoids with molecular insights.
Medicinal Chemistry Research, 2011
Biochanin A (BCA) is a methoxylated isoflavone which is the major constituent in red clover and i... more Biochanin A (BCA) is a methoxylated isoflavone which is the major constituent in red clover and in commercially available extracts of this plant. The objective of this study was to evaluate the bioavailability and pharmacokinetics of BCA in female rats after oral and intravenous routes of administration. The bioavailability of BCA was found to be approximately 4.6%. BCA was found
Malaria Journal, 2011
Despite the wide spread use of lumefantrine, there is no study reporting the detailed preclinical... more Despite the wide spread use of lumefantrine, there is no study reporting the detailed preclinical pharmacokinetics of lumefantrine. For the development of newer anti-malarial combination(s) and selection of better partner drugs, it is long felt need to understand the detailed preclinical pharmacokinetics of lumefantrine in preclinical experimental animal species. The focus of present study is to report bioavailability, pharmacokinetics, dose linearity and permeability of lumefantrine in rats.
Journal of Chromatography B, 2009
A simple, sensitive and rapid method for the analysis of lumefantrine in rat plasma using liquid ... more A simple, sensitive and rapid method for the analysis of lumefantrine in rat plasma using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed. Detection was performed by positive ion electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode. The method included a chromatographic run of 5 min using a C 18 analytical column and the calibration curve was linear over the concentration range of 2-500 ng/mL with a correlation coefficient (r) of 0.996 or better. The intra-and inter-day assay precision ranged from 1.5 to 7.5% and 5.5 to 7.7%, respectively, and intraand inter-day assay accuracy was between 91.3-109.7% and 97.0-104.7%, respectively. The method was successfully applied for the pharmacokinetic study in rats.
Journal of Chromatography B, 2010
A new simple, rapid, sensitive and accurate quantitative detection method using liquid chromatogr... more A new simple, rapid, sensitive and accurate quantitative detection method using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for the measurement of formononetin (FMN) and daidzein (DZN) levels in rat plasma is described. Analytes were separated on a Supelco Discovery C18 (4.6x50 mm, 5.0 microm) column with acetonitrile: methanol (50:50, v/v) and 0.1% acetic acid in the ratio of 90:10 (v/v) as a mobile phase. The method was proved to be accurate and precise at linearity range of 5-100 ng/mL with a correlation coefficient (r) of &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; or = 0.996. The intra- and inter-day assay precision ranged from 1.66-6.82% and 1.87-6.75%, respectively; and intra- and inter-day assay accuracy was between 89.98-107.56% and 90.54-105.63%, respectively for both the analytes. The lowest quantitation limit for FMN and DZN was 5.0 ng/mL in 0.1 mL of rat plasma. Practical utility of this new LC-MS/MS method was demonstrated in a pharmacokinetic study in rats following intravenous administration of FMN.
Journal of Chromatography B, 2008
A highly sensitive and specific HPLC-ESI-MS/MS method has been developed and validated for the es... more A highly sensitive and specific HPLC-ESI-MS/MS method has been developed and validated for the estimation of centchroman with 100 L rat plasma using tamoxifen as an internal standard (IS). The assay procedure involved a single-step, liquid-liquid extraction of centchroman and IS from plasma with 2.5% (v/v) isopropanol in n-hexane, which yielded consistent recoveries of 109.5 and 107.8% for centchroman and IS in rat plasma, respectively. The total chromatographic run time was 3.8 min. Peaks were resolved using 0.01 M ammonium acetate (pH 4.5):acetonitrile (10:90, v/v) mobile phase on a Supelco Discovery C 18 column. Specificity and matrix effect on ionization was determined and found that method was specific and there was no significant matrix effect. Linearity range was found to be 0.5-100.0 ng/mL with a correlation coefficient (r) of 0.9959 or better. The intra-and inter-day assay precision ranged from 3.3 to 9.0% and 5.5 to 6.8%, respectively, and intra-and inter-day assay accuracy was between 93.4-107.1% and 96.2-104.2%, respectively. Stability of centchroman in rat plasma was >89.0% in the battery of stability studies viz., bench-top, auto-sampler, freeze/thaw cycles and 30 days storage in a freezer at −80 • C. The assay was successfully applied to determine the pharmacokinetic parameters in Sprague-Dawley rats after an oral administration of centchroman at 20 mg/kg. As a result, the plasma half-life was 29.4 ± 2.3 h and the AUC (0-∞) was 7345.1 ± 21.9 ng h/mL. The maximum plasma concentration (C max ) 117.5 ± 15.7 ng/mL was achieved at 9.0 ± 8.6 h (t max ).
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Scientific Papers by Muhammad Wahajuddin
Papers by Muhammad Wahajuddin