This document discusses various classes of antineoplastic agents (cancer drugs). It describes:
1. Alkylating agents which form covalent bonds with cells and crosslink DNA, including nitrogen mustards, methanesulfonates, ethylenimines, and nitrosoureas.
2. Antimetabolites which interfere with DNA and RNA synthesis, including folate antagonists, purine and pyrimidine antagonists.
3. Antibiotics such as dactinomycin and daunorubicin which inhibit DNA and RNA polymerase or intercalate into DNA.
2. These are the agents which inhibit the development of
neoplasm, a new & abnormal growth (cancer cells) (or) modify their
growth.
CLASSIFICATION:
A. Alkylating agents:
These are subdivided into four classes such as:
Nitrogen mustards (or) Mustards
Methanesulphonates
Ethylenimines
Nitrosoureas
ANTINEOPLASTIC AGENTS
6. NITROGEN MUSTARDS
1. MECHLORETHAMINE:
Structure:
C.N:
Syn:
M.OA:
Agents have groups that form covalent bond with cell substitutents
a carbonium ion is the intermediate. Most have two alkylating gps
(Bifunctional) can crosslink two nucleophilic sites such as the N7 of
Guanine in DNA.
ALKYLATING AGENTS
7. &thymine, leading to substitution of AT for GC (or) chain breakage.
All alkylating agents depress bone marrow function & cause
gastrointestional disturbances.
With prlonged use, two further unwanted effect occurs.
a) Depression of Gametogenesis in men.
b) Increased risk of acute non-lympholytic leukaemia & other
malignancies.
Use: Used in the treatment for mytosis fungoides & Lymphomas.
2. MELPHANAN
Structure:
C.N:
9. M.O.A:
Serves as a Primary Immunosuppressive drugs.
USE:
Very effective in preventing the reoccurence of cancer in
premenopansal women.
3. CYCLOPHOSPHAMIDE:
Structure:
C.N:
Syn:
12. M.O.A:
Non-specific phase
Almost negligible action on rapidly prloiferative tissues other than
bone marrow.
At relatively lower dose level granulo-cytopoesis may be
suppressed & without causing any effect on erythropoises.
USE:
Used in the treatment for Granuocytic leukemeia.
16. USE:
Possesses the potential to cross BBB.
Employed specifically for brain tumour & other tumours,
for instance leukemias, which have metastasized to the
brain.
Combination of Carmustine & prednisone used for the
treatment of multiple mycloma
Used for the treatment of lymphomas & Hodgkin’s
Disease.
Used for the treatment of Glioblastoma
25. M.O.A:
The ‘drug’ is believed to be a glutamine antagonist that specifically inhiits
purine biosynthesis and thus may exert antitumour activity.
C. ANTIBIOTICS
26. USE:
Useful in the treatment of acute lymphoblastic leukemia in
children. It is normally employed in combination therapy, for instance :
with cytosine arabinoside in the treatment of myclogenous leukemia ; with
cytarabine in the treatment of non-lymphoblastic leukemia in adult.
27. M.O.A:
Dactinomycin
Inhibits the DNA-dependent RNA-polymerase. Interestingly, the drug also
significantly potentiates radiation recall (otherwise known as ‘radiotherapy’).
It also serves as a secondary (efferent) immunosuppressive agent.
does not pass the blood-brain barrier (BBB).
Daunorubicin Hydrochloride
intercalates into DNA, inhibits topoisomerase II, yields oxygen radicals,
and ultimately inhibits DNA synthesis. It can invariably prevent and check cell
division in doses that virtually fail tointerfere directly with the nucleic acid
synthesis.