BIOPHARMACEUTICAL PROPERTIES OF SLOW-RELE ASE CODEINE PHOSPHATE - STUDIES OF DRUG-RELEASE FROM A CATION-EXCHANGER IN-VITRO AND IN-VIVO

Biopharmaceutical Properties of Slow-release Codeine Phosphate / Studi es of drug release from a cation exchanger in vitro and in vivo The re lease of bound codeine (CAS 76-57-3) from a cation exchanger was exami ned in vitro by the flow- through method in vivo by measuring the plas ma concentrations of codeine after administration of slow-release (Cod ipront(R) Retard) and standard non-retarded drops. Both sets of result s show that codeine release from the ion exchanger is protracted and c ontinuous. Relative to the standard formulation the slow-release codei ne drops give a lower maximal plasma concentration (C-max), a delayed time of maximal concentration (t(max)), slower absorption (t(0,5)) and protracted plasma levels. The in vitro and in vivo results were in go od agreement.