Influence of liposomal formulation variables on the interaction with Candida albicans in biofilm; a multivariate approach.

Candida albicans is a species commonly associated with biofilm formation. The aim of this study was to identify liposomal formulation variables influencing the adhesion of liposomes to C. albicans in biofilm. C. albicans was grown on microtiter plates. Charged liposomes containing a fluorescent phospholipid (fatty acid labeled) were adsorbed onto biofilms of C. albicans in the wells. The adsorption was quantified by fluorescence measurements. Statistical experimental design and multivariate evaluation were used in the studies. The liposomal formulation factors investigated were the type of the main phospholipid (egg-PC, DMPC, and DPPC), the amount of charged component in the liposomes, and the type of the charged lipid (diacyl-TAP, DC-chol, diacyl-PA, diacyl-PG, diacyl-PS, and PI). Full factorial mixed levels designs were created. Saturated positively charged liposomes, with diacyl-TAP as the charged component and a low level of positive charge, was found to be the best choice for interaction with C. albicans. When formulating negatively charged liposomes, liposomes with DPPC as the main lipid adsorbed significantly better than liposomes with egg-PC. The amount of charge and the nature of the charged component were not found to influence the adsorption of the negatively charged liposomes to C. albicans. No synergy was detected between any of the formulation variables studied.