5297-05-2Relevant academic research and scientific papers
Regioselective Schiff's base mediated deglycosidation of digitalis glycosides. New efficient synthesis of digoxigenin bis-digitoxoside and digoxigenin mono-digitoxoside
Adamczyk, Maciej,Grote, Jonathan
, p. 63 - 66 (1995)
Dialdehydes derived from digoxin glycosides via sodium periodate oxidation were regioselectively deglycosylated by various amino acids in anhydrous methanolic solution to afford excellent yields of digoxigenin bis-digitoxoside and digoxigenin mono-digitoxoside in a single step.
Metabolism of digoxin and digoxigenin digitoxosides in rat liver microsomes: Involvement of cytochrome P4503A
Salphati, Laurent,Benet, Leslie Z.
, p. 171 - 185 (2007/10/03)
1. The sequential metabolism of digoxin (Dg3) to digoxigenin bis-digitoxoside (Dg2), digoxigenin mono-digitoxoside (Dg1) and digoxigenin (Dg0) was investigated in rat liver microsomes. 2. Kinetic studies produced results consistent with a single enzyme mechanism describing the successive oxidative cleavages. Formation of Dg2 was catalysed with mean (± SD) K(m) and V(max) of 125 ± 22 μM and 362 ± 37 pmol/min/mg protein, respectively. The corresponding values for the formation of Dg1 were 61 ± 5 μM and 7 ± 1 pmol/min/mg protein. Dg0 formation was catalysed with the apparent values of 30 ± 9 μM and 310 ± 30 pmol/min/mg protein. 3. Chemical inhibition of cytochrome P450 (CYP) 3A subfamily with ketoconazole and triacetyoleandomycin decreased the formation of Dg2 and Dg1 by up to 90%. Antibodies specific to rat CYP3A2 lowered the rate of oxidative cleavage of Dg3 and Dg2 by up to 85%. Inhibition of CYP2E1, CYP2C subfamily and CYP1A2 by chemical and immunoinhibition did not affect initial rates of metabolism of Dg3 and Dg2. In contrast, Dg1 metabolism was not affected by triacetyloleandomycin as well as by antibodies to CYP3A2, CYP2C11, CYP2E1, CYP2B1/2B2 and CYP1A2. It was however inhibited by > 80% by gestodene and 17α-ethynylestradiol (selective inhibitors of human CYP3A). 4. Collectively, these data support the involvement of CYP3A in the cleavage of Dg3 and Dg2 in rat liver microsomes. The enzyme-metabolizing Dg1 remains to be identified.
Effect of cyclodextrins on the acid hydrolysis of digoxin.
Uekama,Fujinaga,Hirayama,Otagiri,Kurono,Ikeda
, p. 627 - 630 (2007/10/02)
The effects of three cyclodextrins (alpha-, beta-, gamma-CyD) on the acid hydrolysis of digoxin were examined. From the high performance liquid chromatographic tracing of each of the four components (digoxin, bisdigitoxoside, monodigitoxoside, digoxigenin) in reaction mixtures, the individual rate constants (K1-K6) were determined by analogue computer simulation. The hydrolysis was suppressed by CyDs in the order of beta-great than gamma-greater than alpha-greater than-CyD, where beta-CyD inhibited the appearance rates of digoxigenin (k3, K5, and K6) significantly. In the dissolution study of digoxin tablets, the increase in dissolution rate and decrease in acid hydrolysis were attained by inclusion complexation. The data are presented suggesting that CyDs are useful for improving the oral bioavailability of digoxin.
