The correlation of plasma protein binding and molecular properties of selected antifungal drugs

Antifungal agents are the group of drugs commonly prescribed in the treatment of fungal infections, which are widely spread among the global population. Their properties, such as absorption, distribution, metabolism, route of elimination or plasma protein binding (PPB), considerably influence their therapeutic success, while a number of the molecular physicochemical properties of the drug notably influence all these processes. Lipophilicity (log P), molecular weight (Mw), volume (Vol), polar surface area (PSA) and solubility (log S) play important roles in drug absorption, penetration into tissues, distribution and route of elimination or the degree of plasma protein binding. In this study, the relationships between these five molecular properties of eight antifungal drugs and their plasma protein binding data obtained from relevant literature were investigated. The Selected physicochemical molecular descriptors of the drug were calculated using software packages. The established relationships between PPB and PSA; Mw; Vol and log S were showed relatively poor correlation (r < 0.35). The best correlation was obtained for the relationship between PPB data and the lipophilicity descriptor X log P3 (correlation coefficient r = 0.55). In further investigation, multiple linear regression analysis was applied. The best correlation was obtained with application of lipophilicity with polar surface area (r = 0.918) and volume (r = 0.916) or molecular weight (r = 0.896) as independent variables.