5-Fluoro-2-deoxycytidine is a fluorinated pyrimidine analog antimetabolite with potential antineoplastic activity. As a prodrug, 5-fluoro-2-deoxycytidine is converted by intracellular deaminases to the cytotoxic agent 5-fluorouracil (5-FU). 5-FU is subsequently metabolized to active metabolites including 5-fluoro-2-deoxyuridine monophosphate (FdUMP) and 5-fluorouridine triphosphate (FUTP). FdUMP binds to and inhibits thymidylate synthase, thereby reducing the production of thymidine monophosphate, which leads to depletion of thymidine triphosphate and the inhibition of DNA synthesis and cell division. FUTP competes with uridine triphosphate (UTP) for incorporation into the RNA strand, which results in the inhibition of RNA and protein synthesis and cell proliferation. 5-Fluoro-2-deoxycytidine undergoing trials to test its effectiveness in treating cancer that has not responded to standard therapies.

Lapachone (aka beta-Lapachone) is an ortho naphthoquinone, originally isolated from a tree whose extract has been used medicinally for centuries. It has garnered interest as a potential therapeutic or lead compound against a number of disease conditions including cancers, and blindness due to retinopathy of prematurity. It is lethal to a number of cancer cell types at micromolar concentrations, and it is capable of enhancing the efficacy of radiation therapies against cultured cells. A number of clinical trials have been conducted.

Pimonidazole (developed as RO 038799) is a derivative of 2-nitroimidazole, which forms adducts (binds to thiol-containing proteins) only at low oxygen tension. Pimonidazole is a novel nontoxic hypoxia marker for the complementary study of tumor hypoxia and cell proliferation in different types of cancer. The drawback of pimonidazole as a hypoxic marker is that it detects only severe hypoxia.

Porfiromycin is an N-methyl derivative of the antineoplastic antibiotic mitomycin-C initially isolated from Streptomyces ardus. Upon administration, the drug undergoes chemical or enzymatic reduction, followed by spontaneous loss of the tertiary methoxy (hydroxyl) group and formation of an aromatic indole system. Thus activated, porfiromycin generates oxygen radicals and alkylates DNA, producing interstrand cross-links and single-strand breaks at guanosine residues. Porfiromycin was tested in phase III for head and neck carcinoma, however, its development was terminated.

PD 176252 is a competitive antagonist of neuromedin-B preferring (BB1) and gastrin-releasing peptide preferring (BB2) receptors. PD176252 inhibited tumor growtn in preclinical model of lung cancer, and exhibited synergy with EGFR inhibitor in the model of head and neck cancer. PD176252 demonstrated anxiolytic properties in preclinical models.

L-fucose is a hexose deoxy sugar found on N-linked glycans on mammalian, insect and plant cell surfaces. Deficiency in L-fucose has been observed in several pathological conditions including cancer and atherosclerosis. On the other hand, L-fucose is an inhibitor of the sodium/myo-inositol transporter which may play a roll in the development of diabetes. L-fucose is has been considered as a diagnostic biomarker in several forms fo cancer.

Amifostine is an organic thiophosphate cytoprotective agent known chemically as 2-[(3¬ aminopropyl)amino]ethanethiol dihydrogen phosphate (ester), it’s adjuvant used in cancer chemotherapy and radiotherapy involving DNA-binding chemotherapeutic agents. It is marketed under the trade name Ethyol. Amifostine is a prodrug and is dephosphorylated by alkaline phosphatase in tissues to a pharmacologically active free thiol metabolite. This metabolite is believed to be responsible for the reduction of the cumulative renal toxicity of cisplatin and for the reduction of the toxic effects of radiation on normal oral tissues. The ability of Ethyol to differentially protect normal tissues is attributed to the higher capillary alkaline phosphatase activity, higher pH and better vascularity of normal tissues relative to tumor tissue, which results in a more rapid generation of the active thiol metabolite as well as a higher rate constant for uptake into cells. The higher concentration of the thiol metabolite in normal tissues is available to bind to, and thereby detoxify, reactive metabolites of cisplatin. This thiol metabolite can also scavenge reactive oxygen species generated by exposure to either cisplatin or radiation. Healthy cells are preferentially protected because amifostine and metabolites are present in healthy cells at 100-fold greater concentrations than in tumor cells.

Beta-carotene is found in many foods and is sold as a dietary supplement. Beta-carotene is a carotenoid, weak antioxidant; precursor of vitamin A, which is essential for vision and growth. Used to reduce the severity of photosensitivity reactions in patients with erythropoietic protoporphyria (EPP). Has been used in high-dose antioxidant supplements containing ascorbic acid and vitamin E with zinc in high-risk patients with age-related macular degeneration. Beta-carotene is also used to decrease asthma symptoms caused by exercise; to prevent certain cancers, heart disease, cataracts; and to treat AIDS, alcoholism, Alzheimer’s disease, depression, epilepsy, headache, heartburn, high blood pressure, infertility, Parkinson’s disease, rheumatoid arthritis, schizophrenia, and skin disorders including psoriasis and vitiligo.

Benzethonium chloride, also known as hyamine, is a synthetic quaternary ammonium salt. It has surfactant, antiseptic, and anti-infective properties and it is used as a topical antimicrobial agent in first aid antiseptics. It is also found in cosmetics and toiletries such as mouthwashes, anti-itch ointments, and antibacterial moist towelettes. Benzethonium chloride exhibits a broad spectrum of microbiocidal activity against bacteria, fungi, mold and viruses. The US Food and Drug Administration (FDA) specifies that the safe and effective concentrations for benzethonium chloride are 0.1-0.2% in first aid products. Aqueous solutions of benzethonium chloride are not absorbed through the skin. It is not approved in the US or Europe for use as a food additive. Being a quaternary ammonium salt, it is more toxic than negatively charged surfactants. However, in a two-year study on rats, there was no evidence of carcinogenic activity. Benzethonium chloride was characterized as a novel anticancer compound possessing both in vitro and in vivo efficacy justifying further investigation.

Proflavine is an acriflavine derivative used as a topical disinfectant agains gram-positive bacteria. Proflavine is toxic and carcinogenic in mammals and so it is used only as a surface disinfectant or for treating superficial wounds. Proflavine acts by interchelating DNA (intercalation), thereby disrupting DNA synthesis and leading to high levels of mutation in the copied DNA strands. This prevents bacterial reproduction. Proflavine was investigated for photodynamic theraphy of herpes but was discontinued due to several presentations of post-treatment Bowen's disease and higher lesion recrudescence periods. Proflavine is also investigated as a topical contrast agent for imaging and diagnosis of esophageal, oral, colon, cervical, uterine cancer and polyps.