Comparison of physicochemical characteristics and stability of three novel formulations of paclitaxel: Abraxane, Nanoxel, and Genexol PM
Bibliographic record
Abstract
5622 Background: Abraxane (Abraxis BioScience, Inc., Los Angeles, CA, approved in USA and Canada), Nanoxel (Dabur Pharma, H.P., India, approved in India), and Genexol PM (Samyang Pharmaceuticals, Seoul, Korea, approved in Korea) are 3 commercially approved, novel formulations of paclitaxel. Abraxane consists of albumin-bound injectable nanoparticles of paclitaxel, while Genexol and Nanoxel (utilizing cosolvents) are polymeric-micelle formulations. Abraxane and Genexol are lyophilized products approved for 25°C ± 2°C storage, while Nanoxel is a liquid formulation approved for 2-8°C storage. This study investigated the physicochemical characteristics and short-term stability of the 3 products under recommended clinical use conditions and under accelerated conditions. Methods: The drugs were reconstituted and prepared per the instructions provided in the respective package inserts. Abraxane and Genexol were reconstituted using the recommended saline diluent, while Nanoxel was mixed and diluted in 10% dextrose. Each drug was reconstituted to 0.7 mg/mL and 5 mg/mL. Physical stability was monitored both visually and microscopically; particle size was measured and monitored over time at room temperature (RT, measured to be 23°C) and 40°C using photon correlation spectroscopy (PCS) (Zetasizer 3000, Malvern, UK). Chemical purity was measured by reduced reversed-phase HPLC (Shimadzu Scientific Instruments, MD). Results: Following reconstitution, Abraxane was determined to be stable both physically and chemically at RT and 40°C over 24 hrs, with no evidence of nanoparticle size growth at either 0.7 mg/mL or 5 mg/mL. While reconstituted Genexol was stable at RT over 24 hrs, micelle instability resulting in precipitation of paclitaxel in the form of large needle-like crystals for both 0.7 mg/mL and 5 mg/mL formulations was seen between 2 to 4 hrs at 40°C. These observations were confirmed using orthogonal techniques, visual assessment from photomicrographs, and PCS particle size measurement. For Nanoxel at 0.7 mg/mL, a minor, but consistent, increase in particle size was observed at RT over 24 hrs. However, significant aggregation, particle-size growth, and crystallization were seen within 4 hrs at 40°C. HPLC data comparing pre- and post-filtration confirmed that the crystal formation for both Nanoxel and Genexol resulted from paclitaxel precipitation and aggregation. In addition, analytical results showed that Nanoxel had slightly lower paclitaxel purity as compared to either Abraxane or Genexol. Conclusions: Nanoparticle albumin-bound paclitaxel, Abraxane, showed excellent physicochemical stability as compared to the micellar formulations, Nanoxel and Genexol. Particle size growth and crystal formation were readily apparent in Nanoxel and Genexol, especially in the short term under accelerated conditions.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".