Calculation of the Median Lethal Dose and Low Lethal Dose Using the CombiStats Biometric Software

The median lethal dose (LD₅₀) and low lethal dose (LD₁₀) are calculated in acute toxicity studies, as well as during specific activity assessment of some medicines. The aim of the study was to develop a procedure for using CombiStats to calculate LD₅₀ and LD₁₀. The authors proposed a step-by-step algorithm for processing bioassay results using the CombiStats biometric software (median effective dose determination model, probit analysis) with conversion of doses to simple fractions (fractions of the maximum dose) to calculate LD₅₀ and LD₁₀. They compared LD₅₀ and LD₁₀ calculation results obtained using CombiStats with those obtained using electronic spreadsheets according to the Bliss–Miller–Tainter–Prozorovsky method described in the State Pharmacopoeia of the Russian Federation (General Monograph 1.1.0014.15). It has been demonstrated that the use of CombiStats sometimes has advantages over the use of the pharmacoepoeial method.

1. Bliss CI, McKellen C. Biological assay. Ann Rev Physiol. 1943;5:479–539. https://doi.org/10.1146/annurev.ph.05.030143.002403

2. Burn JH, Finney DJ, Goodwin LG. Biological standardization. 2nd edition. New York: Oxford University Press; 1950.

3. Babich PN, Chubenko AV, Lapach SN. Application of the probit-analysis in toxicology and pharmacology using Microsoft Excel program for the estimation of pharmacological activity in an alternative form of reactions registration. Sovremennye problemy toksikologii = Modern Problems of Toxicology. 2003;(4):80–8 (In Russ.)

4. Belen’kiy ML. Elements of a quantitative evaluation of the pharmacological effect. Leningrad: Medgiz; 1963 (In Russ.)

5. Prozorovskiy VB. Statistical processing of data of pharmacological investigations. Psikhofarmakologiya i biologicheskaya narkologiya = Psychopharmacology and Biological Narcology. 2007;7(3–4):2090–120 (In Russ.)

6. Urbakh VYu. Biometric methods: statistical processing of experimental data in biology, agriculture and medicine. Moscow: Nauka;1964 (In Russ.)