Stability of pentoxifylline in an extemporaneously prepared oral suspension

The stability of pentoxifylline in an extemporaneously prepared suspension was studied. Twelve 400-mg pentoxifylline tablets were crushed and mixed with water to prepare a 20-mg/mL suspension. The suspension was transferred to 10 amber glass and 10 amber plastic prescription bottles. Five glass and five plastic bottles were stored at 25 degrees C, and the rest were stored at 4 degrees C. Samples were collected before storage and on days 7, 14, 21, 28, 42, 56, 70, and 91 and analyzed in duplicate by stability-indicating reverse-phase high-performance liquid chromatography. Pentoxifylline was stable in the suspension under all storage conditions for the duration of the study. The color, odor, and pH of the suspension did not change appreciably. Some settling of the suspension was noted in all bottles beginning on day 21, but shaking resuspended the settled material. Pentoxifylline 20 mg/mL was stable in an extemporaneously prepared suspension for at least 91 days at 25 or 4 degrees C.