A simple and sensitive HPLC fluorescence method for determination of tadalafil in mouse plasma

Farthing, Christine; Farthing, Don; Koka, Saisudha; Larus, Terri; Fakhry, Itaf; Xi, Lei; Kukreja, Rakesh C.; Sica, Domenic A.; Gehr, Todd W.B.

doi:10.1016/j.jchromb.2010.07.022

Cited by 52 publications

(31 citation statements)

References 18 publications

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“…Desmethylene Tadalafil Assay Concentrations of desmethylene tadalafil in reaction mixtures were determined by a reversed-phase HPLC method, as described by Farthing et al 21) with a minor modification. That is, the total reaction mixture was mixed with 2 mL of 1 M citrate buffer (saturated with NaCl, pH 4.5), and extracted with 5 mL of cyclopentyl methyl ether.…”

Section: Methodsmentioning

confidence: 99%

“…The flow rate of the mobile phase was 0.65 mL/min, and the column temperature was 40°C. Peaks were monitored at an excitation wavelength of 275 nm and an emission wavelength of 335 nm, 21) and the retention time was 3.7 min for desmethylene tadalafil. The quantitation limit for desmethylene tadalafil was 1 nM and the CV for desmethylene tadalafil was 5.13% and 0.85% for concentrations of 5 nM and 50 nM, respectively.…”

Section: Methodsmentioning

confidence: 99%

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Contribution of CYP3A Isoforms to Dealkylation of PDE5 Inhibitors: A Comparison between Sildenafil N-Demethylation and Tadalafil Demethylenation

Takahiro

Nakamura

Kohno

et al. 2015

Biological ^|^ Pharmaceutical Bulletin

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The aim of this study was to characterize the kinetics of metabolite formation of the phosphodiesterase type-5 (PDE5) inhibitors sildenafil and tadalafil by CYP3A4, CYP3A5, and CYP3A7 isoforms. The formations of N-desmethyl sildenafil and desmethylene tadalafil were examined using CYP3A supersomes co-expressing human P450 oxidoreductase and cytochrome b 5 . Both sildenafil N-demethylation and tadalafil demethylenation were catalyzed by CYP3A4, CYP3A5, and to a lesser extent by CYP3A7. The kinetics of desalkyl metabolite formation of the two drugs were well fitted to the Hill equation; however, the Hill coefficients (n) suggested CYP3A-mediated negative cooperativity. Next, we analyzed the kinetics with a two binding sites model assuming two reaction steps: reaction 1 with high-affinity and low-capacity metabolism and reaction 2 with low-affinity and high-capacity metabolism. The kinetics of desalkyl metabolite formation were also fitted to the two binding sites model 1) PDE5 inhibitors have been shown to be an effective vasodilator, and have been used widely as a treatment not only for erectile dysfunction, but also for pulmonary arterial hypertension (PAH).2) Sildenafil and tadalafil are orally active inhibitors of PDE5 that are approved for the treatment of PAH in Japan, but their half-life period in the body differs substantially.3,4) That is, sildenafil has a fairly short half-life of about 4-5 h, whereas tadalafil has a long half-life of about 17.5 h in healthy subjects.5,6) The short half-life of sildenafil makes it the drug of choice in patients with more severe cardiovascular disease, allowing early use of supportive treatment if an adverse clinical event occurs. 7) In contrast, tadalafil has the advantage of once a day dosing compared to sildenafil's three times a day dosing, with implications for patient convenience and compliance. 6,8) Therefore, a transition from sildenafil to tadalafil has been frequently tried in stable patients with PAH. 3,8) In humans, sildenafil is eliminated predominantly by hepatic metabolism and is converted to an active metabolite, N-desmethyl sildenafil, with properties similar to the parent drug.9) The N-demethylation by CYP3A is the major route of metabolism of sildenafil in humans 10) (Fig. 1). Recently, Ku et al. 11) showed that both CYP3A4 and CYP3A5 played a significant role in the metabolism of sildenafil using CYP3A supersomes. That is, the intrinsic clearance for N-dealkylation of sildenafil by CYP3A5 and CYP3A4 were 0.09 and 0.07 µL/ min/pmol P450, respectively. 11) They also demonstrated that the mean rate for N-desalkyl metabolite formation from sildenafil was high in human liver microsome preparations with CYP3A5 activity (heterozygous for CYP3A5*1/*3 alleles) compared to those with null CYP3A5 activity (homozygous for CYP3A5*3 allele).11) These results suggested that genetic polymorphism of CYP3A5 at least partly contributes to interindividual variability in the disposition of sildenafil. On the other hand, tadalafil is eliminated predominantly by oxidative me...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Contribution of CYP3A Isoforms to Dealkylation of PDE5 Inhibitors: A Comparison between Sildenafil N-Demethylation and Tadalafil Demethylenation

Takahiro

Nakamura

Kohno

et al. 2015

Biological ^|^ Pharmaceutical Bulletin

View full text Add to dashboard Cite

show abstract

“…Also, as per literature there are many methods used to validate of tadalafil alone or in combined with other drugs in drug formulation, plasma and other fluids; HPLC (Farthing et al, 2010;Kamepalli Sujana et al, 2012;Rajpar et al, 2012;Nagaraju et al, 2012;Samala et al, 2013). Many methods indicated that HPLC was a consistent way for the evaluation of esomeprazole and tadalafil separately in several samples, such as pharmaceutical formulations, drinks, plasma and other biological fluids, and it can be used to study the pharmacokinetics parameters of these drugs (Onal and Oztunç, 2006;Farthing ;Dilip et al, 2011;Kumar et al, 2011;Jain et al, 2011;Nalwade et al, 2012;Kamepalli Sujana et al, 2012;Rajpar et al, 2012;Nagaraju et al, 2012;Samala et al, 2013). Up to date literature survey indicate no method for simultaneous estimation of both esomeprazole and tadalafil in pharmaceutical formulation.…”

Section: Tadalafilmentioning

confidence: 99%

Simultaneous estimation of Esomeprazole and Tadalafil in pharmaceutical formulations using High Performance Liquid Chromatography

Hamad¹,

Al-Sharqawi²,

Dayyih³

et al. 2016

J App Pharm Sci

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An easily, specific, precise, and accurate reversed-phase HPLC method was developed and validated for simultaneous estimation of esomeprazole ( Nexium ® ) and tadalafil (Cialis ® ) in pharmaceutical formulation. The separation was achieved by using Hypersil BDS C18 column (250 mm × 4.6 mm; 5.0 μm) and acetonitrile: 0.05 M potassium dihydrogen phosphate buffer at pH 6 adjusted with phosphoric acid as a mobile phase at a flow rate of 1 mL/min. Detection was carried out at wavelength 285nm. The retention time of esomeprazole and tadalafil were 3.1, 3.7 min, respectively. The linearity was established over the concentration ranges of 60-180μg/mL and 40-120μg/mL with correlation coefficients 0.9998 and 0.9996 for esomeprazole and tadalafil, respectively. The mean recoveries were found to be in the ranges of 98-102% for esomeprazole and tadalafil. The proposed method has been validated as per ICH guidelines and successfully applied to the simultaneous estimation of esomeprazole and tadalafil in pharmaceutical formulation.

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“…[8] Thus far, several chromatographic methods have been developed for tadalafil determination in plasma, including liquid chromatography (LC) coupled with ultraviolet (UV) [9,10] and fluorescence detection. [11] In recent pharmacokinetic studies, LC-tandem mass spectrometry (LC-MS/MS) has primarily been used for measuring tadalafil in plasma because of its high sensitivity and selectivity. [12][13][14][15][16][17][18][19] Proença et al published a validated ultra-performance liquid chromatography (UPLC)-MS/ MS method for the analysis of sildenafil, vardenafil, and tadalafil in postmortem blood samples.…”

Section: Introductionmentioning

confidence: 99%

Validated UPLC-MS/MS method for the determination of tadalafil in human plasma and its application to a pharmacokinetic study

Kim

Nam

Kwon

et al. 2017

Transl Clin Pharmacol

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A simple, rapid, and reliable UPLC-MS/MS method was developed and validated for the determination of tadalafil in human plasma. The plasma samples were deproteinized with acetonitrile. Chromatographic separation was performed on a Shiseido C18 (100 × 2.1 mm, 2.7 μm) column with isocratic elution using 2.0 mM ammonium acetate and acetonitrile (55:45, v/v) with 0.1% formic acid at a flow rate of 0.7 mL/min. The total run time was 1 min per sample. The quantitative analysis was performed using multiple reaction monitoring at transition of m/z 390.4 → 268.3 for tadalafil and m/z 475.3 → 283.3 for sildenafil as an internal standard. The method was fully validated over a concentration range of 5-1,000 ng/mL with a lower quantification limit of 5 ng/mL. Intra-and inter-day precision (relative standard deviation, %RSD) were within 8.4% and accuracy (relative error, %RE) was lower than -3.2%. The developed and validated method was successfully applied to a pharmacokinetic study of tadalafil (20 mg) in Korean healthy male subjects (n = 12).

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A simple and sensitive HPLC fluorescence method for determination of tadalafil in mouse plasma

Cited by 52 publications

References 18 publications

Contribution of CYP3A Isoforms to Dealkylation of PDE5 Inhibitors: A Comparison between Sildenafil N-Demethylation and Tadalafil Demethylenation

Contribution of CYP3A Isoforms to Dealkylation of PDE5 Inhibitors: A Comparison between Sildenafil N-Demethylation and Tadalafil Demethylenation

Simultaneous estimation of Esomeprazole and Tadalafil in pharmaceutical formulations using High Performance Liquid Chromatography

Validated UPLC-MS/MS method for the determination of tadalafil in human plasma and its application to a pharmacokinetic study

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