Naftopidil-d5 (Synonyms: KT-611-d5; BM-15275-d5)

Naftopidil-d₅ is intended for use as an internal standard for the quantification of naftopidil by GC- or LC-MS. Naftopidil is an antagonist of α₁-adrenergic receptors (α₁-ARs; K_is = 3.7, 20, and 1.2 nM for α_1A-, α_1B-, and α_1D-ARs, respectively).¹ It is selective for α₁-ARs over α₂-ARs (K_i = 1,793 nM).² Naftopidil inhibits norepinephrine-induced contractions in various blood vessels isolated from dog, rabbit, guinea pig, or rat with pA₂ values ranging from 6.73 to 8.15.² It reduces prostatic pressure and mean blood pressure in anesthetized dogs when administered at doses of 100 or 1,000 µg/kg.³ Naftopidil also inhibits the growth of androgen-sensitive LNCaP cells and androgen-insensitive PC3 cancer cells with IC₅₀ values of 22.2 and 33.2 µM, respectively.⁴ Formulations containing naftopidil have been used in the treatment of benign prostatic hyperplasia.

1.Masumori, N.Naftopidil for the treatment of urinary symptoms in patients with benign prostatic hyperplasiaTher. Clin. Risk Manag.7227-238(2011) 2.Muramatsu, I., Yamanaka, K., and Kigoshi, S.Pharmacological profile of the novel α-adrenoceptor antagonist KT-611 (naftopidil)Jpn. J. Pharmacol.55(3)391-398(1991) 3.Takei, R.-i., Ikegaki, I., Shibata, K., et al.Naftopidil, a novel α1-adrenoceptor antagonist, displays selective inhibition of canine prostatic pressure and high affinity binding to cloned human α1-adrenoceptorsJpn. J. Pharmacol.79(4)447-454(1999) 4.Kanda, H., Ishii, K., Ogura, Y., et al.Naftopidil, a selective α-1 adrenoceptor antagonist, inhibits growth of human prostate cancer cells by G1 cell cycle arrestInt. J. Cancer122(2)444-451(2008)