Stability of an extemporaneously compounded baclofen oral liquid.

The stability of baclofen in an extemporaneously compounded oral liquid formulation for 35 days was studied. A suspension was prepared by grinding commercially available 20-mg baclofen tablets and adding Glycerin, USP, to form a paste. Simple Syrup, NF, was added as necessary to make a final volume of 60 mL. A control solution was prepared from analytical-grade baclofen powder in Simple Syrup, NF. The final concentration of baclofen in both formulations was 5 mg/mL. Three samples of each preparation were stored in 2-oz, amber glass prescription bottles in the dark under refrigeration at 4 degrees C. Immediately after preparation and at 7, 14, 21, 28, and 35 days, samples were visually inspected, tested for pH, and assayed in duplicate by high-performance liquid chromatography. On day 35, the mean percentages of the initial baclofen concentrations remaining were 95.9% in the suspension and 95.6% in the solution. The color, odor, and pH of the samples did not change appreciably over the study period. In an extemporaneously compounded oral liquid preparation in Simple Syrup, NF, stored in the dark under refrigeration, baclofen was stable for at least 35 days.