Tadalafil  (Synonyms: IC-351)

Tadalafil (IC-351) is a PDE5 inhibitor with an IC₅₀ value of 1.8 nM.

IC50: 1.8±0.4nM (PDE 5)^[1].

Biochemical potencies (affinities) of these compounds for PDE5 determined by IC(50), K(D) (isotherm), K(D) (dissociation rate), and K(D) ((1/2) EC(50)), respectively, were the following: sildenafil (3.7 +/- 1.4, 4.8 +/- 0.80, 3.7 +/- 0.29, and 11.7 +/- 0.70 nM), tadalafil (1.8 +/- 0.40, 2.4 +/- 0.60, 1.9 +/- 0.37, and 2.7 +/- 0.25 nM); and vardenafil (0.091 +/- 0.031, 0.38 +/- 0.07, 0.27 +/- 0.01, and 0.42 +/- 0.10 nM). Thus, absolute potency values were similar for each inhibitor, and relative potencies were vardenafil >> tadalafil > sildenafil^[1]. 0.5 ml tadalafil solutions with different concentrations were added (0.2, 0.1, 0.05 and 0.025 μg ml-1, respectively) into semen samples. In both groups, samples treated with 0.2 μg ml-1 tadalafil had significant increase in sperm motility after 2 h incubation^[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

The Tadalafil-treated group showed enhanced erectile function (intracavernosal pressure/mean arterial pressure) at 0.3, 0.5, 1, 3, and 5 Hz compared with diabetic group values at the respective frequencies that approached control values^[3]. oral administration of tadalafil (20 mg) or sildenafil (100 mg) was given. In both groups, computer-assisted semen analysis parameters showed no significant difference. After the administration of tadalafil (2 h) and sildenafil (1 h), there was no significant difference observed in premature acrosome reaction incidence rate^[2].

MCE has not independently confirmed the accuracy of these methods. They are for reference only.

389.40

Solid

C₂₂H₁₉N₃O₄

171596-29-5

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Room temperature in continental US; may vary elsewhere.

• [1]. Blount MA, et al. Binding of tritiated sildenafil, tadalafil, or vardenafil to the phosphodiesterase-5 catalytic site displays potency,specificity, heterogeneity, and cGMP stimulation. Mol Pharmacol. 2004 Jul;66(1):144-52.  [Content Brief]

  [2]. Yang Y, et al. Effect of acute tadalafil on sperm motility and acrosome reaction: in vitro and in vivo studies. Andrologia. 2013 Apr 14. [Epub ahead of print]  [Content Brief]

  [3]. Mostafa ME, et al. Effect of Chronic Low-dose Tadalafil on Penile Cavernous Tissues in Diabetic Rats. Urology. 2013 Jun;81(6):1253-60.  [Content Brief]