Physicochemical stability of azacitidine suspensions at 25 mg/mL in polypropylene syringes stored under different conditions of storage

Objectives

Azacitidine is a pyrimidine nucleoside analogue whose stability is temperature dependent. Numerous publications have studied the stability of this drug with discordant results. The purpose of this work is to study the stability of azacitidine suspensions under different conditions to allow preparation in advance: vials stored at room temperature or between 2 and 8 °C, reconstituted with refrigerated water for injection (WFI) or frozen/thawed WFI, azacitidine suspensions stored at room temperature, 2–8 °C or at −20 °C. The feasibility of a vented ChemoClave® Spike vial was also tested to reconstitute and collect azacitidine to aid the preparation stage.

Methods

The stability study was performed by HPLC coupled to a photodiode array detector. The method was validated according to ICH Q2(R1). Two syringes were prepared for each analysis condition and two samples were realised for each syringe at each time of the analysis. For a storage at 2–8 °C, analyses were performed for up to 168 h. The stability was studied after 2 h at room temperature. For frozen storage, the stability was studied after 28 days.

Results

Azacitidine 25 mg/mL suspensions stored between 2 and 8 °C, prepared with refrigerated WFI or frozen/thawed WFI, retained more than 90% of the initial concentration for 96 h and then for 2 h at room temperature. Prepared with frozen/thawed WFI, azacitidine 25 mg/mL suspensions stored at −20 °C for 28 days and then 72 h between 2 and 8 °C after thawing, retained more than 90% of the initial concentration. When using a Spike system compared to using a needle for reconstitution and collection of the suspension, the results obtained by HPLC showed a decrease of 1.47% in the concentration of azacitidine. The comparisons of the volumes withdrawn after reconstitution were similar when using a Spike system or a needle.

Conclusions

Azacitidine 25 mg/mL suspensions reconstituted with refrigerated WFI were chemically stable for 4 days when stored at 2–8 °C whatever the storage of vials (refrigerator or room temperature), and 2 h at room temperature. A storage of azacitidine 25 mg/mL suspensions in syringes prepared with frozen/thawed WFI at −20 °C has been validated for up to 28 days, leading to the possibility to prepare in advance. A Spike device can be used to reconstitute and collect azacitidine.

Azacitidine Omega-3 Self-Assemblies: Synthesis, Characterization, and Potent Applications for Myelodysplastic Syndromes

5-Azacitidine, a cytidine analogue used as a hypomethylating agent, is one of the main drugs for the treatment of myelodysplastic syndromes (MDSs) and acute myeloid leukemia (AML) in the elderly. However, after administration, it exhibits several limitations, including restricted diffusion and cellular internalization due to its hydrophilicity, and a rapid enzymatic degradation by adenosine deaminase. The aim of this study was to improve the drug cell diffusion and protect it from metabolic degradation via the synthesis of amphiphilic prodrugs and their potential self-assembly. Azacitidine was conjugated to two different omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The carboxylic acid group of the omega-3 fatty acids was effectively conjugated to the amine group of the azacitidine base, yielding two amphiphilic prodrugs. Nanoprecipitation of the obtained prodrugs was performed and self-assemblies were successfully obtained for both prodrugs, with a mean diameter of 190 nm, a polydispersity index below 0.2 and a positive zeta potential. The formation of self-assemblies was confirmed using pyrene as a fluorescent dye, and the critical aggregation concentrations were determined: 400 µM for AzaEPA and 688 µM for AzaDHA. Additionally, the stability of the obtained self-assemblies was studied and after 5 days their final stable arrangement was reached. Additionally, cryo-TEM revealed that the self-assemblies attain a multilamellar vesicle supramolecular structure. Moreover, the obtained self-assemblies presented promising cytotoxicity on a leukemia human cell line, having a low IC50 value, comparable to that of free azacitidine.

Development and Validation of a New Storage Procedure to Extend the In-Use Stability of Azacitidine in Pharmaceutical Formulations

Stability studies performed by the pharmaceutical industry are principally designed to fulfill licensing requirements. Thus, post-dilution or post-reconstitution stability data are frequently limited to 24 h only for bacteriological reasons, regardless of the true physicochemical stability which could, in many cases, be longer. In practice, the pharmacy-based centralized preparation may require preparation in advance for administration, for example, on weekends, holidays, or in general when pharmacies may be closed. We report an innovative strategy for storing resuspended solutions of azacitidine, a well-known chemotherapic agent, for which the manufacturer lists maximum stability of 22 h. By placing the syringe with the azacitidine reconstituted suspension between two refrigerant gel packs and storing it at 4 °C, we found that the concentration of azacitidine remained above 98% of the initial concentration for 48 h, and no change in color nor the physicochemical properties of the suspension were observed throughout the study period. The physicochemical and microbiological properties were evaluated by HPLC–UV and UHPLC-HRMS analysis, FTIR spectroscopy, pH determination, visual and subvisual examination, and sterility assay. The HPLC-UV method used for evaluating the chemical stability of azacitidine was validated according to ICH. Precise control of storage temperature was obtained by a digital data logger. Our study indicates that by changing the storage procedure of azacitidine reconstituted suspension, the usage window of the drug can be significantly extended to a time frame that better copes with its use in the clinical environment.