Factors Affecting the Use of Impedance Spectroscopy in the Characterisation of the Freezing Stage of the Lyophilisation Process: the Impact of Liquid Fill Height in Relation to Electrode Geometry
Journal Title: AAPS PharmSciTech - Year 2014, Vol 15, Issue 2
Abstract
This study aims to investigate the application of impedance spectroscopy using fixed electrode geometries on a standard glass vial in the characterisation of the freezing process of solutions at different fill liquid volumes. Impedance spectra (between 10 and 106 Hz) were recorded every 3 min, during the freezing cycle on a solution of 30 mg/mL sucrose contained within 10 mL glass vials having an electrode system (two thin copper foils: w, 18 mm; h, 5 mm) affixed to the external surface of the vial. A fill factor (Φ) was defined in terms of the relative height of the solution volume to the height of the electrodes from the base of the vial. Solution volumes of 1.5 to 5 mL (corresponding to Φ= 0.5–1.6) were investigated to establish the applicability of having a fixed electrode geometry for a range of solution volumes. A linear relationship between the time duration of the ice formation/solidification phase and the fill factor suggests that fixed electrode geometries may be used to investigate a range of fill volumes. The benefit of this approach is that it does not invade the solution and hence records the freezing process without providing additional nucleation sites and in a manner which is representative of the entire fill volume.
Authors and Affiliations
Geoff Smith, Muhammad Sohail Arshad, Eugene Polygalov, Irina Ermolina
Keywords
Related Articles
- EP ID EP682347
- DOI 10.1208/s12249-013-0054-y
- Views 95
- Downloads 0
Comments on “Prediction of Drug Solubility in Lipid Mixtures from the Individual Ingredients”
Influence of β-cyclodextrin on the Properties of Norfloxacin Form A
Cyclodextrins are able to form host–guest complexes with hydrophobic molecules to result in the formation of inclusion complexes. The complex formation between norfloxacin form A and β-cyclodextrin was st...
Model Drug as Pore Former for Controlled Release of Water-Soluble Metoprolol Succinate from Ethylcellulose-Coated Pellets Without Lag Phase: Opportunities and Challenges
The objective of the present study was to evaluate the feasibility of using model drug metoprolol succinate (MS) as a pore former to modify the initial lag phase (i.e., a slow or non-release phase in the first 1–...
A Co-blended Locust Bean Gum and Polymethacrylate-NaCMC Matrix to Achieve Zero-Order Release via Hydro-Erosive Modulation
Locust bean gum (LBG) was blended with a cellulose/methacrylate-based interpolyelectrolyte complex (IPEC) to assess the hydro-erosive influence of addition of a polysaccharide on the disposition and drug delivery propert...
Nanoemulsions in Translational Research—Opportunities and Challenges in Targeted Cancer Therapy
Nanoemulsion dosage form serves as a vehicle for the delivery of active pharmaceutical ingredients and has attracted great attention in drug delivery and pharmacotherapy. In particular, nanoemulsions act as an excellent...