Compatibility and Stability of VARUBI (Rolapitant) Injectable Emulsion Admixed with Intravenous Palonosetron...

Prophylaxis or therapy with a combination of a neurokinin 1 (NK-1) receptor antagonist (RA), a 5-hydroxytryptamine-3 (5-HT3) RA, and dexamethasone is recommended by international antiemesis guidelines for the prevention of chemotherapy-induced nausea and vomiting for patients receiving highly emetogenic chemotherapy and for selected patients receiving moderately emetogenic chemotherapy. VARUBI (rolapitant) is a substance P/NK-1 RA that was recently approved by the U.S. Food and Drug Administration as an injectable emulsion in combination with other antiemetic agents in adults for the prevention of delayed nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy, including, but not limited to, highly emetogenic chemotherapy. Palonosetron is one of the 5-HT3 RAs indicated for the prevention of nausea and/or vomiting associated with initial and repeat courses of emetogenic cancer therapy, including high-dose cisplatin. Herein, we describe the physical and chemical compatibility and stability of VARUBI injectable emulsion (166.5 mg/92.5 mL [1.8 mg/mL, free base], equivalent to 185 mg of rolapitant hydrochloride) admixed with palonosetron injection 0.25 mg free base in 5 mL (equivalent to 0.28 mg hydrochloride salt) and with either 5 mL (20 mg) or 2.5 mL (10 mg) of dexamethasone sodium phosphate. Admixtures were prepared and stored in VARUBI injectable emulsion ready-to-use glass vials as supplied by the rolapitant manufacturer and in four types of commonly used intravenous administration (tubing) sets. Assessment of the physical and chemical compatibility and stability of the admixtures in the VARUBI ready-to-use vials stored at room temperature (20°C to 25°C) under fluorescent light and under refrigeration (2°C to 8°C protected from light) was conducted at 0, 1, 6, 24, and 48 hours, and that of the admixtures in the intravenous tubing sets was evaluated at 0, 2, and 6 hours of storage at 20°C to 25°C. Physical stability was evaluated by visual examination of the container contents under normal room light, and measurement of turbidity, globule size, and particulate matter. Chemical stability was assessed by measuring the pH of the admixture and determining drug concentrations (potency) and impurity levels by high-performance liquid chromatographic analysis. All samples were physically and chemically compatible throughout the study duration. The pH, turbidity, globule size, and particulate matter of the admixture stayed within narrow and acceptable ranges. VARUBI injectable emulsion admixed with intravenous palonosetron and dexamethasone was chemically and physically stable in the ready-to-use glass vials for at least 24 hours at room temperature and 48 hours under refrigeration, as well as in the four selected intravenous tubing sets for at least 6 hours at room temperature. No decrease of drug concentration (or potency) of any admixed components occurred in the samples stored at the two temperature ranges and time periods studied as measured by high-performance liquid chromatographic analysis.