Detail of "38677-81-5"

Reference

Selected ion monitoring assay for the bronchodilator pirbuterol

Selected ion monitoring assay for the bronchodilator pirbuterol. Falkner, Fred C.; McIlhenny, Hugh M. (Drug Metab. Dep., Pfizer Inc., Groton, Conn., USA). Biomed. Mass Spectrom., 3(5), 207-11 (English) 1976. CODEN: BMSYAL. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacodynamics) Section cross-reference(s): 13 A selected ion monitoring assay is reported for the detn. of plasma levels pirbuterol (I) [38677-81-5] in man and animals. I is extd. from plasma with Me2CO and K2CO3 and, after purifn., is converted to the Me3CCO deriv. Using a stable isotope labeled internal std. precisions of 10 and 6% were achieved at plasma concns. of 1 and 20 ng/mL, resp.

Relative efficacy of prenalterol and pirbuterol for beta-1 adrenoceptors: measurement of agonist affinity by alteration of receptor number

Relative efficacy of prenalterol and pirbuterol for beta-1 adrenoceptors: measurement of agonist affinity by alteration of receptor number. Kenakin, Terry P.; Beek, Deborah (Wellcome Res. Lab., Burroughs Wellcome Co., Research Triangle Park, NC 27709, USA). J. Pharmacol. Exp. Ther., 229(2), 340-5 (English) 1984. CODEN: JPETAB. ISSN: 0022-3565. DOCUMENT TYPE: Journal CA Section: 2 (Mammalian Hormones) Section cross-reference(s): 1 Both prenalterol [57526-81-5] and pirbuterol [38677-81-5] are partial agonists (when compared to isoproterenol [7683-59-2]) in rat left atria. Schild anal. with the b1-adrenoceptor selective antagonist atenolol indicated that all 3 agonists stimulate b1-adrenoceptors in this prepn. Atria from rats implanted with mini-osmotic pumps which delivered isoproterenol (400 mg/kg/h) s.c. for 4 days were 9 times less sensitive than control, to isoproterenol, and produced no responses to either prenalterol or pirbuterol. Schild anal. with atenolol on these desensitized atria indicated a homogeneous population of b1-adrenoceptors. In the desensitized atria, both prenalterol and pirbuterol functioned as competitive antagonists of responses to isoproterenol, and Schild anal. yielded ests. of the equil. dissocn. const. (Kp) of prenalterol (0.09 mm) and pirbuterol (2 mm) in these tissues. The ests. of Kp were utilized to calc. the relative efficacy of pirbuterol and prenalterol; pirbuterol had 2.3 times the efficacy of prenalterol on b1-adrenoceptors. The implications of this method as a means of calcg. the Kp for partial agonists are discussed. These data also serve as a caveat to the use of pirbuterol in the detn. of functional cardiac b-adrenoceptor subtypes in exptl. animals and in man.