title: Influence of composition and preparation parameters on the properties of aqueous monoolein dispersions.
abstract: Colloidal cubic phase particles formed in the monoolein/poloxamer/water system are being investigated as potential drug carriers for, e.g., intravenous administration. Preparation methods must, however, still be further developed to reliably yield monoolein dispersions with cubic particles in a size range acceptable for i.v. administration and adequate long-term stability. In this context, the influence of different composition and preparation parameters on the properties of monoolein dispersions prepared by high-pressure homogenization was studied. High pressure homogenization of coarse poloxamer 407-stabilized monoolein/water mixtures leads to dispersions with a large fraction of micrometer-sized particles at low poloxamer concentrations. Higher poloxamer concentrations lead to lower mean particle sizes but the fraction of cubic particles becomes smaller and vesicular particles are observed instead. A study of the characteristics of a dispersion with a standard composition indicated that the homogenization temperature has a much stronger influence on the dispersion properties than the homogenization pressure or the type of homogenizer used. Temperatures around 40-60 degrees C lead to the most favorable dispersion properties. The high temperature sensitivity of the preparation process appears to be at least partly correlated with the phase behavior of the dispersed particles determined by temperature-dependent X-ray diffraction.
authors.affiliation: Institute of Pharmacy, Department of Pharmaceutical Technology, Friedrich Schiller University Jena, Lessingstrasse 8, D-07743 Jena, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Wörle
authors.forename: M
authors.initials: M
authors.lastname: Drechsler
authors.forename: M H J
authors.initials: MH
authors.lastname: Koch
authors.forename: B
authors.initials: B
authors.lastname: Siekmann
authors.forename: K
authors.initials: K
authors.lastname: Westesen
authors.forename: H
authors.initials: H
authors.lastname: Bunjes
mesh_terms: D004655:Emulsions; D005989:Glycerides / Q000737:chemistry; D053758:Nanoparticles; D044367:Phase Transition; D020442:Poloxamer; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D004655:Emulsions; D005989:Glycerides; D014867:Water; D020442:Poloxamer; C005953:monoolein