[The relative bioavailability of paracetamol following administration of solid and liquid oral preparations and...

Determination of the Relative Bioavailability of Paracetamol Following Administration of Solid and Liquid Oral Preparations and Rectal Dosage Forms. The relative bioavailability of paracetamol from two solid and two liquid oral preparations and two rectal dosage forms, each containing 500 mg of the active ingredient, was investigated in 12 healthy male individuals. The plasma concentration-time curves of paracetamol following administration of the oral formulations were very similar; consequently there were only minor differences of the AUC0-12h (21.4, 21.9; 23.0, 22.8 micrograms.h/ml), cmax (8.8, 9.1; 10.0, 10.7 micrograms/ml), tmax (35, 25; 20, 19 min), and the terminal plasma elimination half-life t1/2 beta (2.95, 2.85; 2.86, 2.99 h) for the solid and the liquid test and reference preparations, respectively. The suppositories (test and reference formulation) differed from the oral dosage forms, but were comparable to each other with respect to AUC0-12h (18.2, 18.8 micrograms.h/ml), cmax (3.3, 3.5 micrograms/ml), tmax (1.6, 2.45 h), and t1/2 beta (3.55, 3.54 h). In all test preparations the 95% confidence limits for AUC0-12h completely were enclosed in the range of 80-120% relative bioavailability (independently of whether parametric or non-parametric statistical methods were applied); the limits for the oral formulations were quite narrow, thus indicating a highly consistent release of the active compound from the tablets as well as from the liquid dosage form. A comparison of the mean values of cmax by analysis of variance at the 80% probability level did not reveal any significant differences between the test and the corresponding reference formulations; based on non-parametric statistical methods, the 95% confidence limits for cmax were enclosed in the range of 70-130%.(ABSTRACT TRUNCATED AT 250 WORDS)