Swelling Behavior and Controlled Release of Theophylline and Sulfamethoxazole Drugs in β-Lactoglobulin Protein Gels Obtained by Phase Separation in Water/Ethanol Mixture

• Published in: Biomacromolecules Vol. 7; no. 1; pp. 323 - 330
• Main Authors: Reddy, Thimma T, Lavenant, Laurence, Lefebvre, Jacques, Renard, Denis
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.01.2006
• Subjects: Applied sciences; Biological and medical sciences; Chemical and Process Engineering; Engineering Sciences; Ethanol - chemistry; Exact sciences and technology; Food engineering; Gels - chemistry; General pharmacology; Kinetics; Lactoglobulins - chemistry; Life Sciences; Medical sciences; Natural polymers; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Phase Transition; Physicochemistry of polymers; Proteins; Solubility; Solvents - chemistry; Sulfamethoxazole - chemistry; Theophylline - chemistry; Water - chemistry; Solvent effect; Swelling; Control release polymer; β-Lactoglobulin; Physical gel; Drug carrier; Antiasthma agent; Experimental study; In vitro; Protein; Sulfamethoxazole; Medium effect; Antiinfectious; Kinetics; Hydrogel; Release; Theophylline; DRUG; SWELLING; LACTOGLOGULINE BETA; LIBERATION CONTROLEE; BETA LACTOGLOBULIN; CONTROLLED RELEASE; GELATION
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm050688d

Physically cross-linked β-lactoglobulin (BLG) protein gels containing theophylline and sulfamethoxazole low molecular weight drugs were prepared in 50% ethanol solution at pH 8 and two protein concentrations (6 and 7% (w/v)). Swelling behavior of cylindrical gels showed that, irrespective of the hydrated or dehydrated state of the gel, the rate of swelling was the highest in water. When the gels were exposed to water, they first showed a swelling phase in which their weight increased 3 and 30 times for hydrated and dehydrated gels, respectively, due to absorption of water, followed by a dissolution phase. The absorption of solvent was however considerably reduced when the gels were exposed to aqueous buffer solutions. The release behavior of both theophylline and sulfamethoxazole drugs from BLG gels was achieved in a time window ranging from 6 to 24 h. The drug release depended mainly on the solubility of the drugs and the physical state of the gel (hydrated or dry form). Analysis of drug release profiles using the model of Peppas showed that diffusion through hydrated gels was governed by a Fickian process whereas diffusion through dehydrated gels was governed partly by the swelling capacities of the gel but also by the structural rearrangements inside the network occurring during dehydration step. By a judicious selection of protein concentration, hydrated or dehydrated gel state, drug release may be modulated to be engineered suitable for pharmaceutical as well as cosmetics and food applications.