Detail of "72088-94-9"

Reference

Storage stability of dispersions of soybean lecithin liposomes

Storage stability of dispersions of soybean lecithin liposomes. Part 3. Kibat, P. G.; Stricker, H. (Inst. Pharm. Technol. Biopharm., Univ. Heidelberg, Heidelberg 6900, Fed. Rep. Ger.). Pharm. Ind., 48(10), 1184-9 (German) 1986. CODEN: PHINAN. ISSN: 0031-711X. DOCUMENT TYPE: Journal CA Section: 63 (Pharmaceuticals) Carboxyfluorescein (I) [72088-94-9] (model) contg.-liposomes were obtained by different methods using hydrogenated soybean lecithin such as Epikuron 2005H and cholesterol [57-88-5]. Liposomes produced by ultrasound and contg. cholesterol showed the same stability and vesicle size after 6-mo storage at 6° and 25° as the liposomes produced by detergent dialysis, while the particle size of the cholesterol-free small unilamellar vesicles stored at 25° increased. In addn., liposomes from the hydrogenated soybean lecithin and from mixts. with cholesterol were stable. Drug release studies carried out at 6° show a shelf-life of >1 yr. After 1 yr storage of the liposomes contg. the soybean lecithin, the lysolecithin content (degraded product) showed the highest increase in samples stored at 37° whereas for those stored at 6° it showed the smallest increase.

Weak acid-induced release of liposome-encapsulated carboxyfluorescein

Weak acid-induced release of liposome-encapsulated carboxyfluorescein. Barbet, Jacques; Machy, Patrick; Truneh, Alemseged; Leserman, Lee D. (Cent. Immunol., INSERM-CNRS, Marseille 13288/9, Fr.). Biochim. Biophys. Acta, 772(3), 347-56 (English) 1984. CODEN: BBACAQ. ISSN: 0006-3002. DOCUMENT TYPE: Journal CA Section: 63 (Pharmaceuticals) Leakage of the entrapped anionic fluorophore carboxyfluorescein (I) [72088-94-9] was used as a measure of the permeability of liposomes to several different acids. I leakage increased with increasing buffer concn. at a given pH and depended on its chem. nature: apolar weak acids such as AcOH [64-19-7] or pyruvic acid [127-17-3] induced fast leakage at pH 4-5, while glycine [56-40-6], aspartic [56-84-8], citric acid [77-92-9] and HCl induced leakage only at lower pH. Fluorescence leakage measurements reflected the acidification of the liposomes' aq. spaces, which was primarily caused by the diffusion of undissocd. acid mols. across the lipid bilayer. A simple math. model in accord with this hypothesis and assuming that I leakage was directly related to the proportion of its natural lactone form, described satisfactorily the I leakage kinetics and allowed rough estn. of permeability coeffs. for I (neutral lactone form: 9×10-9 cm/s), AcOH (> 1×10-7 cm/s) and glycine (cation: 6×10-9 cm/s). These results are consistent with low effective proton permeability of liposomes (< 5×10-12 cm/s) and with the permeability coeff. of HCl (3×10-3 cm/s) reported by Nozaki and Tanford (1981). Diffusion of weak acid mols. across lipid membranes has implications for drug encapsulation and delivery, and may be of biol. significance.