SEQUENTIAL-INJECTION SYSTEM FOR DRUG-DISSOLUTION STUDIES OF IBUPROFENTABLETS AND SUSTAINED-RELEASE FORMULATIONS

An automated system for drug-dissolution studies based on the sequenti al-injection (SI) technique is described and evaluated for monitoring of dissolution profiles of ibuprofen tablets, sustained-release capsul es and controlled-release matrix tablets. The system was composed of a computer-controlled syringe pump and a multi-position selection valve and coupled to a spectrophotometric detector. An 800 mu l test soluti on in dissolution vessel was aspirated sequentially into a PTFE holdin g coil via on-line filters. After delivering an aliquot (40 mu l) of e ach aspirated solution into the transferring line connected to the det ector, the residual dissolution solution in the holding coil was fed b ack to the dissolution vessel to clear the filter and decrease sample consumption. The sampled aliquot was carried to the detector and monit ored at 222 nm. Every hour, seven samples run in hexa-replicates were processed with a total of 42 measurements. The system was continuously run for 12 h with an overall relative standard deviation of 2.18% (n= 72) at 50% final concentration level of the dissolution solution, whic h demonstrates the stability and robustness of the automated SI system . (C) 1998 Elsevier Science B.V.