• George R. Lankas
  • Lea R. Gordon


Abamectin (MK-0936) is a natural fermentation product of Streptomyces avermitilis. Ivermectin (MK-0933) is a synthetic derivative of abamectin. The chemical structure of abamectin differs from ivermectin only in the bond between carbons 22 and 23; abamectin has a double bond where ivermectin has a single bond and additional hydrogens on C-22 and C-23 (Figure 6.1). Both compounds are a mixture of homologous products with B1a and B1b components. The B1b component differs chemically from the B1a component by only 1 methylene (CH2) unit at the 26-carbon position: the ethyl group (C2H5) is a methyl group (CH3) in the B1b form. Abamectin and ivermectin are defined as containing a minimum of 80% B1a, and a maximum of 20% B1b components. Studies in our laboratories have clearly demonstrated that the individual components have very similar biological and toxicological properties and, for all practical purposes, can be considered equivalent.


Body Weight Gain Cleft Palate Developmental Toxicity Cleave Palate Oral Toxicity Study 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Amano Y (1967) Changes of the levels of blood glucose during pregnancy in the rat. Jap. J. Pharmacol. 17:105–114PubMedCrossRefGoogle Scholar
  2. Ames BN, McCann J, Yamasaki E (1975) Methods for detecting carcinogens and mutagens with the Salmonella/mammalian microsome mutagenicity test. Mutat. Res. 31:347–364PubMedGoogle Scholar
  3. Betz L, Goldstein GN (1981) Developmental changes in metabolism and transport properties of capillaries isolated from rat brain. J. Physiol. 312:365–376PubMedGoogle Scholar
  4. Bohr V, Mollgard K (1974) Tight junctions in human fetal choroid plexus visualized by freeze-etching. Brain Res. 81:314–318PubMedCrossRefGoogle Scholar
  5. Brent RL (1986) Definition of a teratogen and the relationship of teratogenicity to carcinogenicity. Teratol. 34:359–360CrossRefGoogle Scholar
  6. Campbell WC, Benz GW (1984) Ivermectin: a review of efficacy and safety. J. Vet. Pharm. & Therap. 7:1–16CrossRefGoogle Scholar
  7. Chiu SH, Sestokas E, Taub R, Buhs RP, Green M, Sestokas R, Vandenheuval WJ, Arison BH, Jacob TA (1986) Metabolic disposition of ivermectin in tissues of cattle, sheep, and rats. Drug Me tab. & Dispos. 14:590–600Google Scholar
  8. Clive D, Flamm W, Machesko M, Bernheim J (1972) A mutational assay system using the thymidine binase locus in mouse lymphoma cells. Mutat. Res. 16:77–87PubMedGoogle Scholar
  9. Clive D, Spector JASF (1975) Laboratory procedure for assessing specific locus mutations at the TK locus in cultured L5178Y mouse lymphoma cells. Mutat. Res. 31:17–29PubMedGoogle Scholar
  10. Cooper JR (1982) Amino acids. In Cooper JR, Bloom FR, Roth RH (eds), The Biochemical Basis of Neuropharmacology, 4th ed., Oxford University Press, p 250Google Scholar
  11. Cutler SJ, Ederer F (1958) Maximum utilization of the life table method in analyzing survival. J. Chron. Dis. 8:699–712PubMedCrossRefGoogle Scholar
  12. Greene BM, Taylor HR, Cupp EW, Murphy RP, White AT, Aziz MA, Schulz-Key H, D’Anna SA, Newland HS, Goldschmidt LP, Auer C, Hanson AP, Freeman SV, Reber EW, Williams PN (1985) Comparison of ivermectin and diethylcarbamazine in the treatment of onchocerciasis. New Eng. J. Med. 313:133–138PubMedCrossRefGoogle Scholar
  13. Harter HL (1957) Error rates and sample sizes for range tests in multiple comparisons. Biometrics 13:511–36CrossRefGoogle Scholar
  14. Khera KS (1984) Maternal Toxicity—A possible factor in fetal malformation in mice. Teratol. 29:411–416CrossRefGoogle Scholar
  15. Mantel N (1963) Chi-square tests with one degree of freedom; extensions of the Mantel-Haenszel procedure. J. Am. Stat. Assoc. 58:690–700CrossRefGoogle Scholar
  16. Mantel N (1980) Assessing laboratory evidence for neoplastic activity. Biometrics 36:381–99PubMedCrossRefGoogle Scholar
  17. Mantel N, Ciminera J (1979) Use of log-rank scores in the analysis of litter- matched data on time to tumor appearance. Cane. Res. 39:4308–4315Google Scholar
  18. Mantel N, Tukey JW, Ciminera JL, Heyse, JF (1982) Tumorigenicity assays, including use of the jackknife. Biomet. J. 24:579–596CrossRefGoogle Scholar
  19. Peto R (1974) Guidelines on the analysis of tumor rates and death rates in experimental animals. Brit. J. Cane. 29:101–105CrossRefGoogle Scholar
  20. Peto R, Pike MC, Day NE, Gray RC, Lee PN, Parish S, Peto J, Richards S, Wahrendorf J (1980) Guidelines for simple, sensitive significance tests for carcinogenic effects in long term animal experiments. In International Association for Research on Cancer Monographs, Supplement 2, Lyon, France, pp. 365–367Google Scholar
  21. Robson DS (1959) A simplified method for constructing orthogonal polynomials when independent variable is unequally spaced. Biometrics 15:187–191CrossRefGoogle Scholar
  22. Saunders NR (1977) Ontogeny of the blood-brain barrier. Exper. Eye Res. (Suppl.), pp 523–550Google Scholar
  23. Scow RO, Chernick SS, Brinley MS (1964) Hyperlipemia and ketosis in the pregnant rat. Am. J. Physiol. 206:796–804PubMedGoogle Scholar
  24. Setlow RB, Carrier WL (1964) The disappearance of thymine dimers from DNA: An error correcting mechanism. Proc. Natl. Acad. Sci. USA 51:226–231PubMedCrossRefGoogle Scholar
  25. Tukey JW, Ciminera JL, Heyse JF (1985) Testing the statistical certainty of a response to increasing doses of a drug. Biometrics 41:295–301PubMedCrossRefGoogle Scholar
  26. Wester RC, Maibach HI (1975) Percutaneous absorption in the rhesus monkey compared to man. Toxicol. & App. Pharm. 32:394–398CrossRefGoogle Scholar
  27. Wester RC, Maibach HI (1983) Cutaneous pharmacokinetics. 10 steps to percutaneous absorption. Drug Metab. Rev. 14(2): 169–205PubMedCrossRefGoogle Scholar
  28. Wilkins RJ, Hart RW (1973) Preferential DNA repair in human cells. Nature 247:35–36CrossRefGoogle Scholar
  29. Williams GM, Laspia MF, Dunkel, VC (1982) Reliability of the hepatocyte primary culture/DNA repair test in testing coded carcinogens and non- carcinogens. Mutat. Res. 97:359–370PubMedGoogle Scholar

Copyright information

© Springer-Verlag New York Inc. 1989

Authors and Affiliations

  • George R. Lankas
    • 1
  • Lea R. Gordon
    • 1
  1. 1.Department of Safety AssessmentMerck Sharp & Dohme Research LaboratoriesWest PointUSA

Personalised recommendations