Paclitaxel ( CAS: 33069-62-4)

Paclitaxel is a mitotic inhibitor used in cancer chemotherapy. It was discovered

in a US National Cancer Institute program at the Research Triangle Institute in

1967 when Monroe E. Wall and Mansukh C. Wani isolated it from the bark of the

 Pacific yew tree, Taxus brevifolia and named ittaxol. Later it was discovered that

 endophytic fungi in the bark synthesize paclitaxel.

When it was developed commercially by Bristol-Myers Squibb (BMS), the generic

name was changed to paclitaxel and the BMS compound is sold under the trademark

 Taxol. In this formulation, paclitaxel is dissolved in Kolliphor EL and ethanol, as a

delivery agent. A newer formulation, in which paclitaxel is bound to albumin, is sold

under the trademark Abraxane.

Paclitaxel is used to treat patients with lung, ovarian, breast, head and neck cancer, and

advanced forms of Kaposi’s sarcoma. Paclitaxel is also used for the prevention of restenosis.

Paclitaxel stabilizes microtubules and, as a result, interferes with the normal breakdown

of microtubules during cell division. Together withdocetaxel, it forms the drug category

of the taxanes. It was the subject of a notable total synthesis by Robert A. Holton 

of Florida State University.

While offering substantial improvement in patient care, paclitaxel has been a relatively

controversial drug. There was originally concern because of the environmental impact

of its original sourcing (no longer used) from the Pacific yew. In addition, the assignment

of rights to Bristol-Myers Squibb and even the name itself were the subject of public

debate and Congressional hearings. Clinicians sometimes use the abbreviation “PTX”

for paclitaxel, although (like many medical abbreviations) it is not a unique identifier.

It is on the World Health Organization’s List of Essential Medicines, a list of the most

important medication needed in a basic health system.