Dry Adsorbed Emulsion: 1. Characterization of an Intricate Physicochemical Structure

• Published in: Journal of pharmaceutical sciences Vol. 89; no. 8; pp. 991 - 999
• Main Authors: Chambin, O., Bellone, C., Champion, D., Rochat‐Gonthier, M.H., Pourcelot, Y.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Inc 01.08.2000; John Wiley & Sons, Inc; Wiley; American Pharmaceutical Association
• Subjects: Adsorption; Biological and medical sciences; dry emulsion; Electron Spin Resonance Spectroscopy; Emulsions; ESR; General pharmacology; Medical sciences; Microscopy, Electron, Scanning; Models, Structural; Particle Size; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; physicochemical characterization; structural model; physicochemical characterization; dry emulsion; ESR; structural model; Particle size; Water oil emulsion; Pharmaceutical technology; Physical properties; Silica; Powder; Manufacturing process; Dosage form; Polarity; Xanthine derivatives; Adsorbent; Surface area; Pulverulent material; Physicochemical properties; Theophylline; Physical structure
• ISSN: 0022-3549; 1520-6017
• DOI: 10.1002/1520-6017(200008)89:8<991::AID-JPS3>3.0.CO;2-#

A recent solid pharmaceutical form called “Dry Adsorbed Emulsion” (DAE) was characterized in morphological and structural fields. A DAE is an intricate system initiated by a water‐in‐oil emulsion including the active drug (i.e., theophylline). Each emulsion phase is adsorbed on pulverulent adsorbents with a suitable polarity (silica) to obtain a free‐flowing powder with nonporous particles of size from 125 to 710 μm, with small specific surface area and a spherical shape. Different methods, such as scanning electron microscopy combined with chemical microanalysis, dying tests, and electron spin resonance studies, allow the formulator to follow the behavior of DAE aqueous and oily phases during the manufacturing process and then to set up a structural model for DAE particles. These DAE particles appear to be made up of a random pack of hydrophilic and hydrophobic particles, containing a liquid phase adsorbed on silica by weak bonds. © 2000 Wiley‐Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 89:991–999, 2000