Beyond use dating of nanoparticle albumin-bound paclitaxel (Pazenir) infusion

Prepared infusions of nanoparticle albumin-bound (nab) paclitaxel are stable for seven days, when stored in a refrigerator, according to researcher Helen Linxweiler (University Medical Centre of Johannes Gutenberg University, Mainz, Germany).

Paclitaxel is widely used in cancer chemotherapy e.g. for treatment of metastatic breast, pancreas and lung cancer. The nab formulation has to be reconstituted and diluted in a carrier solution before administration, but the stability of the prepared solutions is limited to 24 hours in the fridge and four hours at room temperature (15-25°C), according to the manufacturer.

Ms Linxweiler says that this gives rise to some problems in use. It would be helpful to prepare the infusions in advance to avoid delays. Currently, if treatment is postponed, the infusion has to be discarded. Moreover, longer stability would permit use of part-used vials allowing for greater economy.

She conducted a study in which test solutions were prepared in triplicate and stored in the original glass vials or in EVA infusion bags at room temperature and under refrigeration (2-8°C). Serial samples were taken to determine the stability of the drug and also the stability of the nanoparticles.

The results showed that paclitaxel concentrations were unchanged until day 7 in all storage conditions. Particle size increased slowly over time in the refrigerated dispersions but increased rapidly after day 7 in dispersions stored at room temperature.  The SmPC says that dispersion with visible precipitate can be administered if the precipitate is redispersible. In this study non-redispersible particles started to appear at day 5 in the test products stored at room temperature.

Ms Linxweiler concluded that prepared dispersions of nab paclitaxel should be stored at 2-8°C for a maximum period of seven days, in order to ensure microbiological and physicochemical stability.