TD50 | definition of TD50 by Medical dictionary
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TD50 A numerical description of carcinogenic potency, which corresponds to the daily dose-rate (in mg/kg/body weight/day) for life, to induce tumours in half of test animals that would have remained tumour-free at zero dose. TD50 provides a standardised quantitative measure that can be used for comparing and analysing various issues in carcinogenesis. The range of TD50 values across chemicals that are rodent carcinogens is more than 100-million fold.
References in periodicals archive
Cinetica de Primeira Ordem (cm) [k.sub.sul] [TD.sub.50] [TD.sub.90] Erro [chi ([d.sup.-1]) (dias) square] (%) 0-30 0,012 [+ or 59 195 15,4 - ] 0,002 * 50-70 0,026 [+ or 26 87 17,7 - ] 0,004 * * Significativo pelo teste t a 5%; TD50
- tempo para degradacao de 50% da dose Inicial aplicada; TD90 - tempo para degradacao de 90% da dose inicial aplicada
The HERP for each substance is a ratio, of which the denominator is the substance's TD50
-- daily lifetime dose rate estimated to halve the proportion of tumor-free rodents by the end of a standard lifetime -- and the numerator is a dose that might reasonably be taken daily by humans, adjusted for their greater size.