Abstract
In order to improve previous results obtained with studies of PK of Pol in plasma, we set-up a new direct, sensitive Pol assay to compare PK of Pol (the active metabolite of Pon) in S and P. This RIA uses a Cortisol (C) antisera (crossreactions are 46% and 3% with Pol and Pon, respectively), C as standard and 125C as tracer. Parallel displacements of the curves are obtained with both C and Pol. Intra and interassay dispersions are 2.5 and 4.6%, respectively. Each assay uses either 50 (S) or 25 μl (P) in duplicate and the sensitivity threshold is 8 ng/ml. Ten children were studied. All of them were previously treated with Pon (1 to 2 mg/kg/d) and their 0800h C levels were <50 (P) or <8 (S) ng/ml. Ten P and S samples were collected simultaneously before and over 12 hours periods following a unique dose of oral Pon (1mg/kg). Pol peaks occured at similar times in Saliva (77 ± 12 mn) and in Plasma (63 ± 12 ml. S peak values (118 ± 23 ng/ml) were 21 ± 4% (range 3.5 to 44) of those of P peak levels (559 ± 36 ng/ml). Half lifes of Pol were shorter (88 ± 13 mn) and slopes of disappearance (λ) (−9.8 × 10−3) steeper in S than in P (143 ± 13′, p<.001 and −5.2 × 10−3, p<.02, respectively). Correlation between S and P λ was significant (r=.80, p<.01). In conclusion, S samplings provide a non invasive, accurates method for further studies of PK of Pol. In addition the studies reflect the PK of unbound fraction of circulating Pol.
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Raux Demay, M., Simassamy, P. & Girard, F. 154 SALIVARY (S) AND PLASMA (P) PHARMACOKINETICS (PK) OF PREDNISOLONE (Pol) IN CHILDREN TREATED WITH PREDENISONE (Pon). Pediatr Res 24, 542 (1988). https://doi.org/10.1203/00006450-198810000-00175
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DOI: https://doi.org/10.1203/00006450-198810000-00175