Possible Correlation between Virus Particle Size and Activity of Antiviral Agents

Abstract

SOME success has already been achieved in the chemotherapy of infections caused by the larger viruses, but compounds with an equal degree of activity against the smaller viruses seem much more difficult to find. It is therefore natural to enquire whether there is any relationship between the size of virus particles and the activity of chemotherapeutic agents. As a working hypothesis one may adopt the postulates that (a) a compound is maximally efficient if 1 molecule can inhibit the maturation of 1 virus particle, and (b) that to obtain maximal activity each volume of the cytoplasm of the infected cell equivalent to the volume of a virus particle must contain 1 molecule of the compound. From these postulates the minimal inhibitory concentration of a maximally effective compound can be calculated. Thus, 1 molecule must be present in a volume of 4πr³/3, where r is the radius of the virus particle in mμ. In 1 l. there will be 3 × 10²⁴/47πr³ molecules. Since there are 0.606 × 10²⁴ molecules in a gram molecule, this represents a molarity of (0.808πr³)−1, whence log molarity = −0.4045 − 3 log r.