[Basic and clinical studies on clarithromycin in pediatrics].

Clarithromycin (TE-031, A-56268) is a new macrolide antibiotic developed by Taisho Pharmaceutical Co., Ltd. Basic and clinical studies in the field of pediatrics were carried out on a granular preparation and 50 mg tablets of TE-031 designed for use in children. The following results were obtained. 1. Concentrations of TE-031 in the serum and its excretion in the urine were investigated in children. Six children were orally administered with a TE-031 granular preparation at 10 mg/kg in a cross-over study 30 minutes before meal and 30 minutes after meal. When the drug was ingested before meal, the mean peak serum concentration occurred 1 hour later and was 5.32 +/- 1.20 micrograms/ml. The mean half-life of TE-031 in the serum was 3.6 +/- 1.0 hours, and drug levels decreased to 1.94 +/- 0.55 micrograms/ml at 6 hours after dosing. In cases of the postprandial administration, the mean peak serum level was 4.21 +/- 1.25 micrograms/ml, occurring 2 hours after ingestion. The mean serum half-life in these cases was 3.5 +/- 1.3 hours, and serum levels decreased to 1.66 +/- 0.47 micrograms/ml at 6 hours after dosing. Mean urinary recovery rates during the initial 6 hours after ingestion were 30.5 +/- 6.4% in the cases of preprandial administration and 34.7 +/- 7.3% with postprandial administration. In addition, 30 minutes before meal, 50 mg tablets of TE-031 were orally administered to 3 children in a dose level equivalent to approximately 10 mg/kg, followed by monitoring of serum and urinary levels. It was found that the mean serum concentration showed a peak value of 4.10 +/- 0.44 micrograms/ml at 2 hours after dosing, the mean serum half-life was 3.5 +/- 0.7 hours, and the mean level fell to 1.90 +/- 0.55 micrograms/ml by 6 hours after dosing. The mean 6-hour urinary recovery rate was 32.7 +/- 12.1%. On the basis of the above results, it has been surmised that, in comparison to conventional macrolide antibiotics. TE-031 is better maintained in the blood at a high concentration and is more efficiently excreted into the urine. In addition, the data show that the bioavailability of TE-031 is slightly superior when the drug is administered on an empty stomach compared with after a meal. And finally, it was found that the granular and 50 mg tablet preparations of TE-031 are almost equivalent in terms of the absorption and the excretion of the drug.(ABSTRACT TRUNCATED AT 400 WORDS)