Stability of Methadone Hydrochloride for Injection in Saline Solution

ABSTRACTBackground: Until October 2014, methadone hydrochloride forinjection (10 mg/mL) was available in Canada through Health Canada’s Special Access Programme. Diluted to 5 mg/mL in saline, it was used in pediatrics for acute and cancer-related pain. More recently, the department of pharmacy of the Centre hospitalier universitaire Sainte-Justine in Montréal, Quebec, proposed compounding a solution of methadone hydrochloride for injection (5 mg/mL) from bulk powder and saline solution for pediatric administration.Objective: To assess the stability of the proposed compounded preparation.Methods: Solutions of methadone hydrochloride in saline were prepared from bulk powder and stored in clear glass vials for up to 180 days at room temperature (25 °C) or with refrigeration (5 °C), with testing on days 0, 7, 14, 30, 60, 90, and 180. The appearance of the solutions and presence of particulate matter were assessed. A stability-indicating highperformance liquid chromatography (HPLC) method was developed to assay the concentration of methadone over time.Results: No notable changes in appearance of the methadone solution were observed, particle counts did not exceed limits specified by the United States Pharmacopeia, and no microbial growth was observed. The HPLC analysis showed that the concentration of methadone remained above 90% on all study days.Conclusions:Methadone hydrochloride for injection prepared from bulk powder in saline solution at a concentration of 5 mg/mL remained chemically stable for at least 180 days when stored in clear glass vials at 5 °C and at 25 °C.RÉSUMÉContexte : Jusqu’en octobre 2014, le chlorhydrate de méthadone pourinjection (10 mg/mL) était disponible au Canada à l’aide du Programme d’accès spécial de Santé Canada. Dilué à 5 mg/mL dans une solutionsaline, il était utilisé en pédiatrie contre les douleurs aigües et celles liées au cancer. Plus récemment, le département de pharmacie du Centre hospitalier universitaire Sainte-Justine de Montréal au Québec a proposé de préparer une solution de chlorhydrate de méthadone pour injection (5 mg/mL) à partir d’une poudre en vrac et d’une solution saline en vue de l’administrer en pédiatrie.Objectif : Évaluer la stabilité de la préparation proposée.Méthodes : Les préparations de chlorhydrate de méthadone diluées dans une solution saline se font à partir d’une poudre en vrac, elles sont stockées dans des fioles en verre transparent pendant180 jours à la température ambiante (25 °C) ou réfrigérées (5 °C) et sont soumises à des tests les jours 0, 7, 14, 30, 60, 90 et 180. L’apparence des solutions et la présence de substances particulaires ont fait l’objet d’une évaluation. Une méthode de chromatographie liquide à haute performance (CLHP) indiquant la stabilité a été développée pour tester la concentration de methadone dans le temps.Résultats : Aucun changement notable de l’apparence de la solution de méthadone n’a été observé, le nombre de particules ne dépassait pas les limites précisées par l’United States Pharmacopeia et aucune croissance microbienne n’a été observée. L’analyse CLHP a indiqué que la concentration de méthadone était demeurée au-delà de 90% durant toute la durée de l’étude.Conclusions : Le chlorhydrate de méthadone pour injection préparé à partir de poudre en vrac dans une solution saline à une concentration de5 mg/mL est resté chimiquement stable pendant au moins 180 jours lorsqu’il était stocké dans des fioles en verre transparent à 5 °C et à 25 °C

Stability of Extemporaneously Compounded Suspensions of Trimethoprim and Sulfamethoxazole in Amber Plastic Bottles and Amber Plastic Syringes

Background

Trimethoprim (TMP) and sulfamethoxazole (SMX) are widely used, in combination, to treat or prevent various infections. Unfortunately, no liquid oral formulation is currently available in Canada for patients who are unable to swallow tablets.

Objective

To evaluate the stability of suspensions of TMP and SMX (8 and 40 mg/mL, respectively) prepared in Oral Mix or Oral Mix SF vehicle (Medisca Pharmaceutique Inc) and stored for up to 90 days in amber plastic bottles or amber plastic syringes at 5°C or 25°C.

Methods

Suspensions were prepared from bulk powder and from tablets in Oral Mix and Oral Mix SF vehicles, then transferred to amber plastic (polyethylene terephthalate glycol) bottles and plastic oral syringes and stored at 5°C and 25°C. Samples were collected on predetermined study days (0, 7, 14, 23, 45, 60, 75, and 90 days) and analyzed using a validated high-performance liquid chromatography - ultraviolet detection method. A suspension was considered stable if it maintained at least 90% of its initial concentration with 95% confidence. Observations of organoleptic characteristics such as colour and odour, as well as pH, were used to assess physical stability.

Results

Suspensions prepared from bulk powder maintained concentrations of TMP and SMX of at least 97% of the initial concentration over the 90-day study period. No obvious changes in colour, odour, or pH were observed. However, acceptable suspensions could not be prepared from the commercial tablets. A persistent foam that developed at the surface of all suspensions prepared from tablets could result in inconsistent dosing.

Conclusions

Extemporaneously compounded oral suspensions of TMP and SMX (8 and 40 mg/mL, respectively) prepared from bulk powder in Oral Mix and Oral Mix SF vehicles and stored in amber plastic bottles or syringes at 5°C or 25°C remained stable for at least 90 days. Suspensions made from tablets produced unacceptable formulations.

Stability of Dapsone in Extemporaneously Compounded Oral Suspensions

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Stability of N-Acetylcysteine 60 mg/mL in Extemporaneously Compounded Injectable Solutions

Background

N-Acetylcysteine (NAC) administered by the IV route is the current treatment of choice for acetaminophen overdose. However, the protocol approved by health authorities in most countries has a complex dosing regimen, which leads to dosage errors in one-third of cases. Therefore, the Canadian Antidote Guide in Acute Care Toxicology and individual poison centres have begun to recommend a simplified regimen using continuous IV infusion. Unfortunately, no study has demonstrated the stability of IV solutions of NAC at concentrations above 30 mg/mL or in solutions other than 5% dextrose.

Objective

To evaluate the stability of solutions of NAC 60 mg/mL in 0.9% sodium chloride, 0.45% sodium chloride, or 5% dextrose, stored for up to 72 hours in polyvinyl chloride (PVC) bags at 25°C.

Methods

Solutions of the desired concentration were prepared from a commercial solution of NAC 200 mg/mL, with dilution in 0.9% sodium chloride, 0.45% sodium chloride, or 5% dextrose, and were then stored at room temperature in PVC bags for up to 72 hours. At predetermined time points (0, 16, 24, 40, 48 and 72 h), samples were collected and analyzed using a stability-indicating high-performance liquid chromatography method. A solution was considered stable if it maintained at least 90.0% of its initial concentration. Particulate matter count was also evaluated to confirm chemical stability. Finally, organoleptic properties, such as odour and colour, were evaluated to assess the stability of the solutions.

Results

All solutions maintained at least 98.7% of their initial concentration. No obvious changes in odour or colour were observed. Moreover, particle counts remained acceptable throughout the study, according to the criteria specified in United States Pharmacopeia (USP) General Chapter <788>.

Conclusions

NAC 60 mg/mL, diluted in 0.9% sodium chloride, 0.45% sodium chloride, or 5% dextrose and stored in PVC bags at 25°C, was chemically and physically stable for a period of at least 72 hours.

Stability of Methadone Hydrochloride for Injection in Saline Solution

BACKGROUND

Until October 2014, methadone hydrochloride for injection (10 mg/mL) was available in Canada through Health Canada's Special Access Programme. Diluted to 5 mg/mL in saline, it was used in pediatrics for acute and cancer-related pain. More recently, the department of pharmacy of the Centre hospitalier universitaire Sainte-Justine in Montréal, Quebec, proposed compounding a solution of methadone hydrochloride for injection (5 mg/mL) from bulk powder and saline solution for pediatric administration.

OBJECTIVE

To assess the stability of the proposed compounded preparation.

METHODS

Solutions of methadone hydrochloride in saline were prepared from bulk powder and stored in clear glass vials for up to 180 days at room temperature (25 °C) or with refrigeration (5 °C), with testing on days 0, 7, 14, 30, 60, 90, and 180. The appearance of the solutions and presence of particulate matter were assessed. A stability-indicating high-performance liquid chromatography (HPLC) method was developed to assay the concentration of methadone over time.

RESULTS

No notable changes in appearance of the methadone solution were observed, particle counts did not exceed limits specified by the United States Pharmacopeia, and no microbial growth was observed. The HPLC analysis showed that the concentration of methadone remained above 90% on all study days.

CONCLUSIONS

Methadone hydrochloride for injection prepared from bulk powder in saline solution at a concentration of 5 mg/mL remained chemically stable for at least 180 days when stored in clear glass vials at 5 °C and at 25 °C.