PROCAINE INTERACTIONS WITH PHOSPHOLIPID MONOLAYERS AT THE AIR-WATER-INTERFACE

Compressional isotherms of L-alpha-distearoylphosphatidylcholine (DSPC ) monolayers spread on an aqueous subphase containing various concentr ations of procaine (PR) have been recorded. The influence of PR upon t he surface characteristics of DSPC monolayers is studied using the sur face thermodynamics methods. Therefore, the PR adsorption values and p enetration/binding numbers are derived from the compressional isotherm s by means of Gibbs' equation. Results are compared with those obtaine d in the case of stearic acid and L-alpha-dipalmitoylphosphatidylcholi ne monolayers. Differences are discussed in terms of the molecular str ucture and hydrophobic interactions.