Acetate of cyproterone.
With the internal use of the substance, its rapid and complete absorption occurs. Inside the serum, the peak level is observed approximately 1.6 hours after application and is equal to 15 ng / ml. Bioavailability indicators are 88%.
The substance is almost completely synthesized only with plasma albumin. About 3.5-4% of the total serum component of the component has a free form. Ethinyl estradiol causes an increase in the indices of globulin, it is synthesized with sex hormones, but it does not affect the protein bond of cyproterone acetate in any way. The distribution volume of the component is 986 ± 437 liters.
Ciproterone acetate is almost completely metabolized. The main plasma degradation product is 15β-OH-CPA, which is formed with the participation of the CYP3A4 enzyme of the hemoprotein P450. The serum clearance of the substance is 3.6 ml / minute / kg.
Serum index of cyproterone acetate decreases in 2 elimination periods in which the half-life of the substance is 0.8 hours, and also 2.3-3.3 days. Partly the substance is outputted unchanged. Decay products are excreted with bile and urine in a ratio of 2k1. The half-life of the decay products is approximately 1.8 days.
The pharmacokinetic properties of cyproterone acetate do not change under the influence of globulin, which synthesizes the sex hormone. With an everyday intake of drugs, its rate rises by approximately 2.5 times, and at the second stage of the treatment cycle it reaches stability.
With oral use of ethinyl estradiol, it is absorbed completely and quickly. The peak level inside the serum is observed after 1.6 hours and is about 71 pg / ml. During the absorption and during the first hepatic passage the substance undergoes a metabolism, as a result of which the average total bioavailability is about 45% with a significant individual variability (within 20-65%).
Ethinyl estradiol is quite active, but at the same time it is very specific synthesized with serum albumin (by 98%), and also stimulates an increase in the serum levels of globulin, which synthesizes the sex hormone. The distribution volume is approximately 2.8-8.6 l / kg.
The substance undergoes a general conjugation inside the walls of the small intestine, as well as inside the liver. Metabolism occurs mainly through the aromatic hydroxylation process, but a large number of different methylated and hydroxylated degradation products are bound, which have a free form or are conjugated to sulfuric and glucuronic acid. The indicator of the metabolic cleansing factor is 2.3-7 ml / minute / kg.
The indicator of ethinyl estradiol decreases in 2 segments of half-lives, which are approximately 10-20 hours. Excretion of unchanged substance does not occur, and the decay products are excreted with bile, and urine in the proportion of 6k4. The half-life of the decay products is approximately 1 day.
Stable values can be achieved at the 2nd stage of the treatment cycle. Serum values are 60% higher than the individual dosage.