A structurally related series of fluorinated nonionic oxyethylene glycol surfactants of the type CmF2m+1(CH2)(n)O[(CH2CH2O)(p)H], denoted Cm.nEp (where m = 4, 6, or 7, m = 1 or 2, and p = 4 or 6) were synthesized and their surface behavior in aqueous solution was characterized. The ability of these surfactants to form water-in-hydrofluorocarbon (HFC) propellant 134a microemulsions suitable for use in the aerosolized delivery of water-soluble drugs has been investigated. Phase studies showed that, regardless of the composition used, clear one-phase systems could not be prepared if a fluorinated nonionic surfactant was used alone, or in combination with a short or medium fluorocarbon alcohol cosurfactant. Clear one-phase systems could, however, be prepared if a short-chain hydrocarbon alcohol, such as ethanol, n-propanol, or n-pentanol, was used as cosurfactant, with the extent of the one-phase region increasing with decreased chain length of the alcohol cosurfactant. Light-scattering studies on a number of the hydrocarbon-alcoholcontaining systems in the propellant-rich part of the phase diagram showed that only systems prepared with C4.2E6 and propanol contained microemulsion droplets (all other systems investigated were considered to be cosolvent systems). (C) 2003 Elsevier Science (USA). All rights reserved.