TY  - THES
U1  - Dissertation / Habilitation
A1  - Mrazek, Claudia
T1  - Untersuchungen zum Doppelpeak-Phänomen von Talinolol
N2  - keine Angaben
N2  - Oral absorption of the fti-adrenoreceptor blocker talinolol (TAL) is known to be incompletely and erratically. To evaluate the variables in TAL absorption, 100 mg of the drug were given together with paracetamol (100 mg) and retinyl palmitate (100.000 IU) in fast-disintegrating hard capsules, enteric coated capsules and rectal soft capsules to 8 male healthy volunteers (age 21-29 years, body weight 68-86 kg) who fasted for 10 hours before and 5 hours after administration. Food effects on TAL disposition were assessed by eating a continental breakfast at the moment of the expected first TAL peak one hour prior to administration of a hard capsule. Validated HPLC-assays were used for quantitative determinations. Results: Bioavailability of talinolol in enteric-coated and rectal capsules was significantly reduced by about 50 % and 80 %, respectively despite unchanged bioavailability of paracetamol. After TAL in hard capsules, typical double peak phenomena with peaks after 2-3 and 4-6 hours, respectively, occurred in all subjects. Food increased the maximum concentrations significantly (223±76 µg/ml versus 315±122 µg/ml, p<0.05) and shifted the second peak of TAL to shorter tmax (3.8±1.2 h vs 2.1 ±0.6 h, p<0.05) which was in accordance with faster absorption of vitamin A. Pharmacokinetic simulations showed that about half of oral TAL is not directly drained from intestine, which leads to a late second absorption peak in fasting subjects and which reaches blood earlier after a heavy meal. In conclusion, since TAL disposition is under control of P-glycoprotein and MRP2, ABC-transporters of gut mucosa (enterocytes, capillaries) might be involved in splitting TAL absorption into a direct and a delayed part that might be associated with lymphatic flow.
KW  - Talinolol
KW  - Metabolismus
Y2  - 2004
U6  - https://nbn-resolving.org/urn:nbn:de:gbv:9-200426-4
UN  - https://nbn-resolving.org/urn:nbn:de:gbv:9-200426-4
ER  -