Salting-out taste-masking system generates lag time with subsequent immediate release.

Salting-out effects were utilized for developing a multiparticulate system balancing numbness masking and high bioavailability. A "salting-out taste-masking system" consisting of a drug core containing acetaminophen as a model drug, a salting-out layer containing sodium carbonate (Na(2)CO(3)) and hydroxypropylmethylcellulose (HPMC), and a water-penetration-control layer consisting of cetanol was designed and prepared. The system successfully generated a long lag time while achieving immediate drug release. In the system, the Na(2)CO(3) release rate was slower and the lag time was longer than when the water-penetration-control layer was not present. During the release of Na(2)CO(3) from the system, the release of HPMC and drug was suppressed. These results indicated that the water-penetration-control layer maintained a high concentration of Na(2)CO(3), prevented HPMC's dissolution, and generated a long lag time of drug release. The system generated longer lag time and released drug more immediately than formulation containing the water-penetration-control layer of same thickness without the salting-out layers. These results indicated the salting-out layers were necessary for obtain a long lag time and subsequent immediate drug release. This novel taste-masking system has the potential to be a useful multiparticulate dosage form for effective, safe, and user-friendly drug therapy.