(T1530-11-71) Development of Inhalable Inclusion Complexes of Poorly Water Soluble Crizotinib for Treatment of Non-small Cell Lung Cancer

Purpose: Non-small cell lung cancer (NSCLC) is pre-dominant type of lung cancer and is considered a global disorder affecting millions worldwide. Crizotinib (Crizo), an FDA approved drug, is indicated for the treatment of NSCLC. It suppresses cancer growth by inhibiting anaplastic lymphoma kinase (ALK) and hepatocyte growth factor receptor (c-MET) tyrosine kinase. It also activates caspase-3 pathway to induce cell apoptosis. However, despite these multimodal anticancer mechanisms, patients acquire resistance against it and is no longer clinically effective. Additionally, Crizo is a highly hydrophobic compound with poor water solubility and circulation time in the body. In this project, we have used sulfobutylether-β-cyclodextrin (SBECD) to form molecular inclusion complexes with Crizo to increase its aqueous solubility and stability. Moreover, we aim to target Crizo-CD complexes directly to the lungs by using the non-invasive pulmonary delivery by inhalation.

Methods: 1 mg of Crizo was dispersed in different concentrations of aqueous SBECD (0-200 mM). All suspensions were briefly vortexed and kept for end-to-end mixing for a period of 24 h at room temperature. After 24 h, the samples were centrifuged at 10,000×g for10 min and were later filtered using a 0.2 μm polyvinylidenefluoride (PVDF) syringe filter. The filtered solutions were diluted with methanol to quantify Crizo using UV-spectrophotometer at 270 nm. Intrinsic solubility (S₀) of Crizo was also studied in pure water by following the same protocol, but without the addition of CDs. Phase solubility graphs were constructed by plotting the obtained concentration of solubilized Crizo against CD complexations (mM). The aerosolization behavior of the formulation was studied using next generation impactor (NGI). In-vitro anticancer efficacy of the complexes were studied in A549 lung cancer cell lines using MTT assay.

Results: Phase solubility studies (Fig. A) indicated increasing solubility of Crizo with increase in SBECD concentration. The highest solubility of Crizo was observed at 200 mM SBECD concentration and was calculated to be 1,100±0.5 µg/mL, which is a 12-fold increase when compared with the intrinsic solubility of Crizo (95 µg/mL). Particle deposition (%) of Crizo-CD on each stage of the NGI including amount deposited in mouth/throat was studied to determine its aerosolization and deep lung deposition potential (Fig. B). Mean median aerodynamic diameter (MMAD) of 2.9±0.3 μm and fine particle fraction (FPF) of 88.2±2.0% suggested appropriate aerodynamic size range ( < 5 μm) and excellent aerosolization performance of the inclusion complexes that can deliver the drug into the respirable regions of the lungs, especially into the deep lungs. Preliminary in-vitro cytotoxicity studies indicated an IC₅₀ value of 3 and 6 µM for Crizo and Crizo-CD complexes, indicating similar toxicity (Fig C). The higher toxicity of plain Crizo can be attributed to its complete solubility in organic solvents, these results may not reflect in aqueous solution of free drug due to its poor solubility.

Conclusion: These results corroborate SBECD to be a promising drug delivery carrier for Crizo to increase its aqueous solubility. The complexes demonstrated excellent aerosolization characteristics indicating its potential to reach deep lung tissue. In-vitro cytotoxicity studies indicated appreciable toxicity against lung cancer cells.

Fig A

Fig B

Fig C