title: Drug interaction and location in liposomes: correlation with polar surface areas.
abstract: An important step in liposome characterization is to determine the location of a drug within the liposome. This work thus investigated the interaction of dipalmitoylphosphatidylcholine liposomes with drugs of varied water solubility, polar surface area (PSA) and partition coefficient using high sensitivity differential scanning calorimetry. Lipophilic estradiol (ES) interacted strongest with the acyl chains of the lipid membrane, followed by the somewhat polar 5-fluorouracil (5-FU). Strongly hydrophilic mannitol (MAN) showed no evidence of interaction but water soluble polymers inulin (IN) and an antisense oligonucleotide (OLG), which have very high PSAs, interacted with the lipid head groups. Accordingly, the drugs could be classified as: hydrophilic ones situated in the aqueous core and which may interact with the head groups; those located at the water-bilayer interface with some degree of penetration into the lipid bilayer; those lipophilic drugs constrained within the bilayer.
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Tanta, Tanta, Egypt. gmmelmag@yahoo.com
authors.forename: G M M
authors.initials: GM
authors.lastname: El Maghraby
authors.forename: A C
authors.initials: AC
authors.lastname: Williams
authors.forename: B W
authors.initials: BW
authors.lastname: Barry
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry / Q000493:pharmacokinetics; D002152:Calorimetry, Differential Scanning / Q000379:methods; D002626:Chemistry, Pharmaceutical; D015195:Drug Design; D004347:Drug Interactions; D004958:Estradiol / Q000737:chemistry / Q000493:pharmacokinetics; D005472:Fluorouracil / Q000737:chemistry / Q000493:pharmacokinetics; D057927:Hydrophobic and Hydrophilic Interactions; D007444:Inulin / Q000737:chemistry / Q000493:pharmacokinetics; D008081:Liposomes / Q000737:chemistry* / Q000493:pharmacokinetics; D008353:Mannitol / Q000737:chemistry / Q000493:pharmacokinetics; D016376:Oligonucleotides, Antisense; D012995:Solubility; D013499:Surface Properties / Q000187:drug effects*; D014867:Water
chemical_list: D008081:Liposomes; D016376:Oligonucleotides, Antisense; D014867:Water; D015060:1,2-Dipalmitoylphosphatidylcholine; D008353:Mannitol; D004958:Estradiol; D007444:Inulin; D005472:Fluorouracil