title: Galenical development of a new sustained-release theophylline pellet formulation for once-daily administration.
abstract: Euphylong is a sustained-release product consisting of encapsulated pellets covered with a porous membrane. Since the mechanism of release is osmotic, this new formulation has been termed a "micro-osmotic system". The course of theophylline release is linear over a wide range and is independent of pH value, surface tension and buffer concentration of the dissolution medium. Furthermore, the in-vitro release remains largely uninfluenced by the dissolution model used and by agitation of the dissolution medium. Variations in the in-vitro release profiles produce variations in the in-vivo absorption profiles determined by deconvolution. It is therefore possible, irrespective of the dissolution model and medium used, to produce in-vitro release profiles that enable in-vivo absorption to be predicted by varying the thickness or porosity of the membrane.
authors.affiliation: Department of Galenical Development, Byk Gulden Research Center, Konstanz, Fed. Rep. of Germany.
authors.forename: G
authors.initials: G
authors.lastname: Benedikt
authors.forename: V W
authors.initials: VW
authors.lastname: Steinijans
authors.forename: R
authors.initials: R
authors.lastname: Dietrich
mesh_terms: D000328:Adult; D001682:Biological Availability; D003692:Delayed-Action Preparations; D005750:Gastric Juice / Q000378:metabolism; D006801:Humans; D008297:Male; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D009995:Osmosis; D011108:Polymers; D012996:Solutions; D013806:Theophylline / Q000008:administration & dosage* / Q000493:pharmacokinetics
chemical_list: D003692:Delayed-Action Preparations; D008567:Membranes, Artificial; D011108:Polymers; D012996:Solutions; D013806:Theophylline