title: A New Approach for Quantitative Determination of γ-Cyclodextrin in Aqueous Solutions: Application in Aggregate Determinations and Solubility in Hydrocortisone/γ-Cyclodextrin Inclusion Complex.
abstract: Fast and simple high-pressure liquid chromatographic (HPLC) method with charged aerosol detector (CAD) was developed for quantitation of γ-cyclodextrin (γCD) in aqueous solutions. The chromatographic system consisted of a C18 column (i.e., the stationary phase) and an aqueous mobile phase containing 7% (v/v) methanol. Calibration curve was obtained over the γCD concentration range of 0.005%-1% (w/v). The limit of detection and quantitation of γCD were 0.0001% and 0.0002% (w/v), respectively. Formation of γCD aggregates in aqueous solution and their critical aggregation concentration (cac) were determined by both conventional dynamic light scattering method and permeation method using HPLC-CAD for quantitative determination of γCD. The cac of γCD was determined to be 0.95% (w/v) and the amount of γCD self-aggregates increased with increasing γCD concentrations. Also, the developed HPLC-CAD method was used to determine the γCD phase-solubility profile in an aqueous hydrocortisone (HC)/γCD complexation medium. The maximum concentration of dissolved γCD and HC was determined to be 1.47% and 0.31% (w/v), respectively. The membrane permeation method was shown to be a reliable method for determination of metastable γCD aggregates. The HPLC-CAD method was successfully applied for quantitative determination of γCD in aqueous solutions during permeation and phase-solubility studies.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Iceland Reykjavík Iceland.
authors.forename: Phennapha
authors.initials: P
authors.lastname: Saokham
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Iceland Reykjavík Iceland. Electronic address: thorstlo@hi.is.
authors.forename: Thorsteinn
authors.initials: T
authors.lastname: Loftsson
mesh_terms: D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D000067493:Dynamic Light Scattering; D006854:Hydrocortisone / Q000008:administration & dosage / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry; D047408:gamma-Cyclodextrins / Q000737:chemistry*
chemical_list: D000893:Anti-Inflammatory Agents; D047408:gamma-Cyclodextrins; D014867:Water; C023792:gamma-cyclodextrin; D006854:Hydrocortisone
keywords: HPLC (high-performance/pressure liquid chromatography); complex; cyclodextrin; nanoparticle; permeation; self assembly