Evaluation of a Sustained-release Theophylline Liquid Medicine on Dispensing and Patient-teaching

Abstract

THEODUR®syrup (TDRsyr) is the first liquid dosage form of a long-acting theophylline in Japan. The dosage form design, a matrix form containing theophylline, is suspended in Dsorbitol solution having a high viscosity. To ensure its efficacy, it is necessary to develop precise dispensing technigue. The content of theophylline in TDRsyr was measured by highperformance liquid chromatography (HPLC) after methanol extraction. The concentration of theophylline, after being shaken in a container of TDRsyr (20mg/ml), was 101.5w/v% of the indication value. And its coefficient of variation was 0.7%(n=5), conforming that the quantitative method has good reproducibility. For reliable dispensing, shaking the commercial TDRsyr for longer than 40 minutes is required, and shaking must be done in an up-and-down manner 8 times (8 cycles) per second. Moreover, prior taking it as a dosage, it must be shaken for longer than 2 minutes for 4 cycles per second. When a patient measures out the TDRsyr dosage, a measuring cup is found to be more suitable for reliable dispensing than a small pipette.