title: Comparison of ionic and non-ionic drug release from multi-membrane spherical aerogels.
abstract: The presented research was oriented towards the preparation of dry biodegradable alginate aerogels with multi-membranes using a multi-step sol-gel process with potential applications as carriers during oral drug delivery. First alginate spherical hydrogels were formed in CaCl2 or BaCl2 solutions by ionic cross-linking. These cores were further immersed into alginate sodium solution, filtered through a sieve, and dropped into the salt solution again. Multi-membrane hydrogels were obtained by repeating the above process. They were further converted into aerogels by supercritical drying. The effect of the number of membranes was investigated regarding the loading and release of the model drugs nicotinic acid and theophylline. Moreover, the efficiencies of Ba(2+) and Ca(2+) metal ions for forming tridimensional networks that retain and extend drug release were also investigated. Nicotinic acid release was prolonged by adding membranes around the core and using Ca(2+) for cross-linking. However, retarded theophylline release was only obtained by using Ba(2+) for cross-linking. Namely, by increasing the number of membranes and BaCl2 concentration drug release became linear versus time in all studied cases. In the case of nicotinic acid loading increased by adding membranes around the core, however, for theophylline the opposite results were obtained due to the different nature of the model drugs.
authors.affiliation: University of Maribor, Faculty of Chemistry and Chemical Engineering, Smetanova 17, SI-2000 Maribor, Slovenia.
authors.forename: Anja
authors.initials: A
authors.lastname: Veronovski
authors.forename: Zeljko
authors.initials: Z
authors.lastname: Knez
authors.forename: Zoran
authors.initials: Z
authors.lastname: Novak
mesh_terms: D000464:Alginates / Q000737:chemistry*; D017609:Barium Compounds / Q000737:chemistry; D002122:Calcium Chloride / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D002712:Chlorides / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005782:Gels; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D007700:Kinetics; D016014:Linear Models; D008567:Membranes, Artificial; D009525:Niacin / Q000737:chemistry*; D012995:Solubility; D013678:Technology, Pharmaceutical / Q000379:methods; D013696:Temperature; D013806:Theophylline / Q000737:chemistry*
chemical_list: D000464:Alginates; D017609:Barium Compounds; D002712:Chlorides; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005782:Gels; D006603:Hexuronic Acids; D008567:Membranes, Artificial; C024986:barium chloride; D009525:Niacin; D020723:Glucuronic Acid; D013806:Theophylline; D002122:Calcium Chloride
keywords: Alginate gel; Controlled drug release; Drug carrier; Multi-membrane gel; Natural polysaccharide