An Overview of Paclitaxel Delivery Systems

As per the World Health Organization, cancer is the second leading cause of death globally and is responsible for an estimated 9.6 million deaths in 2018. More than 2 million cases of lung and breast cancer have been reported in 2018. Paclitaxel is a natural product based anti-mitotic agent useful for the treatment of lung cancer, ovarian cancer and breast cancer. Paclitaxel exhibits low oral bioavailability due to poor aqueous solubility and poor permeability. Paclitaxel is the first blockbuster anticancer drug with annual sales of more than US $1 billion in 1997. Taxol®, Abraxane® and Genexol PM® are commercial injectable preparations of paclitaxel with a drug loading of not more than 17% w/w. The toxicity issues of Cremophor® EL used in Taxol® led to the development of different delivery systems sans Cremophor® EL. The maximum tolerated dose of Taxol® is 135 mg/m2. Taxol® exhibited hypersensitivity reactions and required use of special IVEX-2 filter to avoid leaching of plasticizer into the product. Genexol PM® was physically unstable and was ineffective against multidrug-resistant tumor treatment. Abraxane® exhibited limited tumor exposure, tumor uptake, tumor regression and higher half-maximal inhibitory concentration.