Stability of labetalol hydrochloride in distilled water, simple syrup, and three fruit juices

Labetalol hydrochloride (HCl) is an effective antihypertensive drug. It is available in a tablet dosage form, which may be difficult to administer to geriatric and pediatric patients. The tablets can be suspended in various liquid vehicles, but its stability under these conditions is unknown. The objective of our study was to determine the stability of labetalol HCl in five liquid vehicles, in both plastic and glass prescription bottles, over a four-week period at room temperature and under refrigeration. Labetalol HCl tablets (Trandate, Glaxo) were triturated, and suspended in distilled water, simple syrup, apple juice, grape juice, and orange juice to approximate concentrations of 7-10 mg/mL. After filtration, the liquids were stored in five amber, plastic prescription bottles, and five amber, glass prescription bottles at 4 degrees C and 23 degrees C. The samples were collected at 0, 24, and 72 hours, and 1, 2, and 4 weeks after initiation of the study. Labetalol HCl was measured by an HPLC method. Because there was no substantial change in labetalol HCl concentration during the study period, the tablet dosage from can be reformulated, stored, and administered to elderly or pediatric patients as a liquid dosage form.