normal host cells from which they originate, so finding unique targets against
which anticancer dru gs can be selectively directed is difficult. Many anticancer
drugs have a marginal selectivity for malignant cells because they target the
reproductive apparatus in cells having high proliferation rates. However,
anticancer drugs having this mechanism of action result in high toxicities
against rapidly dividing normal cells, for example, hair follicles, germ cells, and
hematopoeitic cells, leading to dose-limiting side effects like mucositis,
stomatitis, alopecia, and reproductive effects. The side effects associated with
chemotherapy limit the dose or cumulative doses that can be administered to
patients, which can lead to relapse of the tumor and often the development of
drug resistance. [10].
Pharmacokinetics of anticancer drugs play an important role in determining
the quantitative relationship between drug dose, exposure, and drug activity,
thereby allowing adjustment of the dose to achieve maximum benefit [11, 12].
Improving the pharmacokinetics may result in enhanced antitumor activity and
reduce toxicity (pharmacodynamics). Two important factors influencing the
pharmacokinetics of antitumor drugs are route of administration and type of
formulation [12]. Most anticancer drugs are administered intravenously (IV) due
to its advantages of complete and immediate bioavailability and accurate dosing.
However, due to large volumes of distribution and lower specificity, IV route
exposes whole body with anticancer drugs to obtain high concentration of these
drugs specialized parenteral routes such as intraarterial or intrathecal injection
and direct injection to tumor are practiced [12, 13]. However, these routes of
administrations have a limitation in accessing remote and deep cancer tissues.
The medical community has sought alternative therapies that improve
selective toxicities against cancer cells, that is, therapies that increase efficacy
and/or decrease toxicity, resulting in an increase in the therapeutic indices of
the anticancer drugs. Hence, various drug carriers are developed for delivery of
anticancer drugs and most of these carriers are in nanosize range.
16.1.3 Why Nanotechnology for Treating Cancer?
There are several reasons that nanotechno logy could help transform cancer
research and clinical approaches to cancer care [14]. Most biological processes,
including those processes leading to cancer, occur at the nanoscale. For cancer
researchers, the ability of nanoscale devices to easily access the interior of a
living cell affords the opportunity for unprecedented gains on both clinical and
basic research frontiers.
1. The ability to simultaneously interact with multiple critical proteins and
nucleic acids at the molecular level will provide a better understanding of
the complex regulatory and signaling patterns that govern the behavior of
cells in their normal state as well as the transformation into malignant cells.
2. Nanotechnology provides a platform for integrating research in proteo-
micsthe study of the structure and function of proteins, including the
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