Physicochemical stability of norepinephrine bitartrate in polypropylene syringes at high concentrations for intensive care units

Physicochemical stability of nefopam and nefopam/droperidol solutions in polypropylene syringes for intensive care units

Introduction

Nefopam has been reported to be effective in postoperative pain control with an opioid-sparing effect, but the use of nefopam can lead to nausea and vomiting. To prevent these side effects, droperidol can be mixed with nefopam. In intensive care units, high concentrations of nefopam and droperidol in syringes can be used with a continuous flow.

Objectives

The first objective of this work was to study the physicochemical stability of a nefopam solution 2.5 mg/mL diluted in NaCl 0.9% in polypropylene syringes immediately after preparation and after 6, 24 and 48 hours at room temperature. The second objective was to study the physicochemical stability of mixtures of nefopam 2.5 mg/mL and droperidol 52 µg/mL diluted in NaCl 0.9% in polypropylene syringes at room temperature over 48 hours.

Materials and methods

Three syringes for each condition were prepared. For each time of analysis, three samples for each syringe were prepared and analysed by high performance liquid chromatography coupled to photodiode array detection. The method was validated according to the International Conference on Harmonisation Q2(R1). Physical stability was evaluated by visual and subvisual inspection (turbidimetry by UV spectrophotometry). pH values were measured at each time of analysis.

Results

Solutions of nefopam at 2.5 mg/mL and the mixture of nefopam 2.5 mg/mL with droperidol 52 µg/mL, diluted in NaCl 0.9%, without protection from light, retained more than 90% of the initial concentration after 48 hours storage at 20-25°C. No modification in visual or subvisual evaluation and pH values were observed.

Conclusion

Nefopam solutions at 2.5 mg/mL and the mixture of nefopam 2.5 mg/mL with droperidol 52 µg/mL diluted in NaCl 0.9% were stable over a period of 48 hours at room temperature. These stability data provide additional knowledge to assist intensive care services in daily practice.

Forced degradation studies of norepinephrine and epinephrine from dental anesthetics: Development of stability-indicating HPLC method and in silico toxicity evaluation

Injectable solutions containing epinephrine (EPI) and norepinephrine (NE) are not stable, and their degradation is favored mainly by the oxidation of catechol moiety. As studies of these drugs under forced degradation conditions are scarce, herein, we report the identification of their degradation products (DP) in anesthetic formulations by the development of stability-indicating HPLC method. Finally, the risk assessment of the major degradation products was evaluated using in silico toxicity approach. HPLC method was developed to obtain a higher selectivity allowing adequate elution for both drugs and their DPs. The optimized conditions were developed using a C18 HPLC column, sodium 1-octanesulfonate, and methanol (80:20, v/v) as mobile phase, with a flow rate of 1.5 mL/min, UV detection at 199 nm. The analysis of standard solutions with these modifications resulted in greater retention time for EPI and NE, which allow the separation of these drugs from their respective DPs. Then, five DPs were identified and analyzed by in silico studies. Most of the DPs showed important alerts as hepatotoxicity and mutagenicity. To the best of our acknowledgment, this is the first report of a stability-indicating HPLC method that can be used with formulations containing catecholamines.

Physicochemical stability of an admixture of lidocaine and ketamine in polypropylene syringe used in opioid-free anaesthesia

Objectives

Opioid-free anaesthesia is a treatment strategy of pain management based on the use of drugs such as lidocaine, ketamine and dexmedetomidine that do not interact significantly with opioid receptors. In particular, these drugs are used by anaesthesiologists to ensure adequate levels of analgesia during surgical procedures for burn patients such as daily wound dressings and graft surgeries. Furthermore, for hypothermia prevention and wound-healing purposes, ambient temperature must be kept high for these patients, usually between 27°C and 30°C. To facilitate the use of this technique, clinicians want to mix lidocaine and ketamine in the same syringe. No stability data is available to determine the feasibility of this admixture and at this temperature. The objective was to study the physicochemical stability of lidocaine 20 mg/mL with ketamine 2.5 mg/mL diluted with 0.9% sodium chloride (0.9% NaCl) stored at 28°C in polypropylene syringe for 48 hours.

Methods

Physical stability was evaluated by visual examination and by measuring turbidity with a spectrophotometer. Chemical stability was determined after preparation and after 6, 24 and 48 hours of conservation with a high performance liquid chromatography and pH measurements. The method was validated according to International Conference on Harmonisation Q2(R1) guidelines.

Results

Both lidocaine (99.98%±1.44%) and ketamine (100.70%±0.95%) retained more than 95% of their initial concentration after 48 hours storage. pH measurements remained stable over the course of the study (less than 0.21 point of variation). No signs of physical instability were observed after visual and subvisual inspections.

Conclusions

The physicochemical stability of lidocaine 20 mg/mL and ketamine 2.5 mg/mL diluted with 0.9% NaCl in a polypropylene syringe stored at 28°C protected from light was demonstrated for 48 hours. This infusion technique is therefore feasible from a pharmaceutical point of view in burn-unit settings.

Long-term stability of ready-to-use norepinephrine solution at 0.2 and 0.5 mg/mL

Objectives

Norepinephrine is a vasopressor frequently administered after dilution to treat hypotension and shocks in intensive care units. The stability of norepinephrine is known to be highly sensitive to storage conditions. Moreover, medication errors linked to the dilution step are frequent and may be deleterious for critically-ill patients, especially in intensive care units. This study aimed to evaluate the stability of ready-to-use diluted norepinephrine solutions prepared at two target concentrations (0.2 and 0.5 mg/mL), according to the summary of product characteristics, and stored for 365 days in two containers: AT-closed cyclic olefin copolymer vials, and polypropylene syringes.

Methods

A fast reversed-phase liquid chromatography method coupled with an ultra-violet detector was developed to assess the chemical stability of norepinephrine solutions. Validation was conducted according to the linearity of the calibration ranges, selectivity, sensitivity, accuracy and precision. Dosage, sub-visible particle contamination, pH monitoring and sterility assays were performed. Chemical stability was maintained if the measured concentration respected the lower limit of 90% of the initial concentration. Containers were stored at -20±5°C, +5±3°C and +25±2°C with 60±5% relative humidity in a dark closed enclosure.

Results

Stability was successfully maintained for every concentration and container tested when stored at -20±5°C and +5±3°C. In these storage conditions, particle contamination, pH monitoring and sterility assay respected the required criteria. Chemical degradation and colouring of solutions appeared before the end of the 1 year study period for most norepinephrine solutions stored at room temperature.

Conclusions

Ready-to-use solutions containing 0.2 and 0.5 mg/mL norepinephrine in polypropylene syringes or cyclic olefin copolymer vials must be stored at refrigerated or frozen temperatures to obtain acceptable 1 year shelf-stability. Exposure to higher temperatures significantly decreases shelf-stability. Our study protocol for compounding polypropylene syringes and cyclic olefin copolymer vials containing norepinephrine is adapted to implementation in centralised intravenous additive services.