Alteration in the magnitude of induction of tyrosine transaminase by glucocorticoids. II. Effects of phenobarbital, o,p' DDD and diethylaminoethyl diphenylpropylacetate (SKF 525A) on metabolism of triamcinolone acetonide

Distribution and metabolism of triamcinolone acetonide in the rat embryomaternal unit during a teratogenically sensitive period

The distribution and metabolism of triamcinolone acetonide (TAC) in the rat embryomaternal unit were investigated during a teratogenically sensitive period. Pregnant rats (Day 12 of gestation) were injected im with 0.125 or 0.5 mg/kg [3H]TAC. Maternal plasma and embryos were collected at selected time points and analyzed by HPLC and liquid scintillation counting. No significant differences in the percentage of total radioactivity representing unchanged TAC, concentration of TAC, or its elimination half-life were detected in either plasma or embryos of the two dose groups. These results provide evidence that the metabolism and distribution of TAC in the rat embryomaternal unit are dose independent over this known teratogenic dose range. To determine whether multiple administration of TAC resulted in any alterations in maternal or embryonal exposure, the same parameters were evaluated following one (Day 12), two (Days 12 and 13), or three (Days 12, 13, and 14) injections of [3H]TAC (0.5 mg/kg, im). The only alterations detected were an increase in the percentage of total radioactivity in maternal plasma representing unchanged TAC at 1 hr following the second or third injection and an increase in the embryonal concentration of TAC at the same time points.

Biotransformation rate (in vitro) and systemic potency (in vivo) of the topical glucocorticoid budesonide in male and female rats

Budesonide is a glucocorticoid of clinical interest for the topical treatment of skin and respiratory diseases. The in vitro liver biotransformation rate and in vivo systemic potency (thymus involution) of budesonide were studied in male and female rats. The biotransformation rate of [3H]-budesonide was about 4 times slower in the female than in the male rat liver 9000 g supernatant (t 1/2; 230 and 57 min, respectively). The systemic potency of budesonide after peroral or subcutaneous administration was higher (by factors of 6 and 2, respectively) in the female than in the male rat. These results suggest that the liver biotransformation rate of budesonide is of great importance in reducing its systemic action in the male rat.

Separation of some natural and synthetic corticosteroids in biological fluids and tissues by high-performance liquid chromatography

A high-performance liquid chromatography (HPLC) technique was developed for the determination of radiolabeled triamcinolone acetonide (TAC), cortisol and their metabolites in rhesus monkey plasma, urine and tissue samples. After protein precipitation, the parent compounds and metabolites were simultaneously resolved using a single-column reversed-phase HPLC system. TAC was subsequently verified by mass spectrometry and TAC glucuronide was tentatively identified by enzymatic hydrolysis and mass spectrometry of the hydrolysis product. The endogenous hormones, cortisol and cortisone were presumptively identified by cochromatography with authentic standards on two different HPLC systems and positively identified by reverse-isotope recrystallization. Other metabolites of both compounds were detected by selective enzymatic hydrolysis and HPLC. This method is rapid and reproducible with a total recovery greater than 80%.