Development of modified-release dosage forms containing loratadine and pseudoephedrine sulfate.

Pseudoephedrine sulfate (PES) is a short-acting sympathomimetic amine and decongestant. Loratadine (L) is a long-acting antihistamine, H1 blocker. These drugs administered together provide relief from a whole range of rhinitis (hay fever) symptoms. Combination of both drugs is available in the form of sugar-coated modified-release tablets Clarinase (Schering-Plough). In this product, 5 mg of L and 60 mg of PES is present in the sugar-coating layer ready for an immediate release, and the rest of PES (60 mg) is incorporated in the extended-release core of the tablet. This enables fast as well as prolonged release of PES over 6-8 h. Because the sugar coating technologies are troublesome and rarely used nowadays, the aim of this study was to develop alternative oral dosage forms containing L (5 mg) and PES (120 mg). It was assumed that, similarly to the original product, the total dose of L and the half dose of PES should be released during 1 h and the remaining dose of PES ought to be gradually released for up to 8 h.