Physical compatibility and chemical stability of dezocine and ramosetron in 0.9% sodium chloride injection for patient-controlled analgesia administration

As an antiemetic, 5-hydroxytryptamine type 3 (5-HT(3)) receptor antagonist (ramosetron) is generally administered to prevent and treat postoperative nausea and vomiting induced by intravenous dezocine for patient-controlled analgesia. To date, the physicochemical stability of dezocine-ramosetron admixtures has not been assessed. The primary objective of this study was to evaluate the physicochemical stability of a combination of dezocine and ramosetron in 0.9% sodium chloride (normal saline [NS]) injections. Dezocine-ramosetron admixtures were prepared and stored in glass bottles and polyvinyl chloride (PVC) bags refrigerated at 4°C or stored at ambient temperatures (25°C) for up to 14 days. Initial concentrations were 5.0 mg/100 mL for dezocine and 0.3 mg/100 mL for ramosetron used as the diluents. Stability parameters (drug concentrations and pH values) were determined using high-performance liquid chromatography and pH measurements, respectively. Compatibility (cloudiness, discoloration, and precipitation) was assessed visually. After 14 days at 4 °C or 25 °C, the concentration losses of dezocine and ramosetron were both < 4%. Furthermore, there were no significant changes in color, turbidity, or pH values were observed in any of the batches. The results indicated that mixtures of dezocine and ramosetron in NS injections were continuously physically and chemically stable for 14 days in glass bottles or PVC bags stored at 4 °C or 25 °C.