Dry adsorbed emulsion: 2. Dissolution behaviour of an intricate formulation

• Published in: International journal of pharmaceutics Vol. 235; no. 1; pp. 169 - 178
• Main Authors: Chambin, O, Bérard, V, Rochat-Gonthier, M.H, Pourcelot, Y
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 20.03.2002; Elsevier
• Subjects: Adsorption; Biological and medical sciences; Bronchodilator Agents - chemistry; Bronchodilator Agents - pharmacokinetics; Chemistry, Pharmaceutical; Delayed-Action Preparations - chemistry; Delayed-Action Preparations - pharmacokinetics; Dissolution; Dry emulsion; Emulsions - chemistry; Emulsions - pharmacokinetics; General pharmacology; Medical sciences; Microscopy, Electron, Scanning; Particle; Particle Size; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Powders; Solubility; Sustained release; Theophylline - chemistry; Theophylline - pharmacokinetics; Particle; Dry emulsion; Sustained release; Dissolution; Delivery system; Particle size; Pharmaceutical technology; Controlled release form; Bronchodilator; Disintegration; Dry; Antiasthma agent; In vitro; Emulsion; Adsorption; Dosage form; Solid form; Active ingredient; Xanthine derivatives; Release; Theophylline
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/S0378-5173(01)00991-7

The behaviour of a pharmaceutical form, called dry adsorbed emulsion (DAE), containing a sparingly soluble drug (i.e. theophylline) was studied for dissolution drug release kinetic, in relation with DAE structure characterisation. In vitro dissolution testings were performed under different experimental conditions (medium at pH 1.2 and 7.4, medium with or without surfactant addition, different particle sizes, discrete or densified particles). Discrete DAE particles showed an extended release, in comparison with the native drug powder, depending on both drug solubility in the medium and particle size. The relevance of dissolution data was not improved by surfactant addition (0.1% sodium lauryl sulfate: SLS). After an initial release due to theophylline of the DAE superficial layer, the dissolution followed the Higuchi model. This suggested that DAE behaved as an inert matrix, which controlled drug release by diffusion through the hydrophobic part of the DAE. Densified DAE particles showed a slower dissolution rate than discrete DAE particles, because of their weak wettability and their poor disintegrant properties due to the particulate rearrangement under pressure. Lastly in a technological point of view, DAE could be considered as a potential drug delivery system in capsules or tablets to better control bioavailability of drugs.