Compatibility of caffeine, carvedilol, clomipramine hydrochloride, folic acid, hydrochlorothiazide, loperamide hydrochloride, methotrexate, nadolol, naltrexone hydrochloride and pentoxifylline in SyrSpend SF PH4 oral suspensions.

OBJECTIVES: The objective of this study was to evaluate the compatibility of 10 commonly used active pharmaceutical ingredients (APIs) compounded in oral suspensions using a globally available suspending vehicle (SyrSpend SF PH4 liquid): caffeine 10.0 mg/mL, carvedilol 1.0 mg/mL, clomipramine hydrochloride 5.0 mg/mL, folic acid 1.0 mg/mL, hydrochlorothiazide 5.0 mg/mL, loperamide hydrochloride 1.0 mg/mL, methotrexate 2.5 mg/mL, nadolol 10.0 mg/mL, naltrexone hydrochloride 1.0 mg/mL and pentoxifylline 20.0 mg/mL, stored at both controlled refrigerated (2-8°C) and room (20-25°C) temperature. METHODS: Compatibility was assessed by measuring the per cent recovery at different time points throughout a 90-day period. Quantification of the APIs was performed by high performance liquid chromatography (HPLC-UV) using a stability-indicating method. RESULTS: Methods were adequately validated. Forced degradation studies showed that at least one parameter influenced the stability of the APIs. All suspensions were assayed and showed API contents of between 90% and 110% over 90 days. DISCUSSION: Given the percentage of recovery of the APIs within the suspensions, the expiration date of the final products (API+vehicle) was found to be at least 90 days for all suspensions, for both controlled refrigerated and room temperature. CONCLUSIONS: The results suggest that SyrSpend SF PH4 liquid is a stable suspending vehicle for compounding APIs from different pharmacological classes.