Propofol (2,6-diisopropylphenol) is an intravenous anaesthetic agent used for induction and maintenance of general anaesthesia. IV administration of propfol is used to induce unconsciousness after which anaesthesia may be maintained using a combination of medications. It is extensively metabolized, with most of the administered dose appearing in the urine as glucuronide conjugates. Favorable operating conditions and rapid recovery are claimed as the main advantages in using propofol, whereas disadvantages include a relatively high incidence of apnea, and blood pressure reductions. The action of propofol involves a positive modulation of the inhibitory function of the neurotransmitter gama-aminobutyric acid (GABA) through GABA-A receptors. Due to its high lipid-solubility, propofol was initially formulated as a solution with the surfactant Cremophor EL, but the occurrence of pain on injection and anaphylactoid reactions prompted to search for alternative formulations. Results from using cyclodextrins, water-soluble prodrugs, and adopting Bodor's approach to the site-specific chemical delivery system (CDS), as well as the advantages provided by computer-controlled infusion systems, are examined in some detail.

Hydroquinone, aka benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, a derivative of benzene, having the chemical formula C6H4(OH)2. Its chemical structure features two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid. Substituted derivatives of this parent compound are also referred to as hydroquinones. The name "hydroquinone" was coined by Friedrich Wöhler in 1843. In human medicine, hydroquinone is used as a topical application in skin whitening to reduce the color of skin. It does not have the same predisposition to cause dermatitis as metol does. In 2006, the United States Food and Drug Administration revoked its previous approval of hydroquinone and proposed a ban on all over-the-counter preparations. The FDA stated that hydroquinone cannot be ruled out as a potential carcinogen. This conclusion was reached based on the extent of absorption in humans and the incidence of neoplasms in rats in several studies where adult rats were found to have increased rates of tumours, including thyroid follicular cell hyperplasias, anisokaryosis (variation in nuclei sizes), mononuclear cell leukemia, hepatocellular adenomas and renal tubule cell adenomas. One of the components in TRI-LUMA Cream, hydroquinone, is a depigmenting agent, and may interrupt one or more steps in the tyrosine-tyrosinase pathway of melanin synthesis. However, the mechanism of action of the active ingredients in TRI-LUMA Cream in the treatment of melasma is unknown.

The mitomycins are a family of aziridine-containing natural products isolated from Streptomyces caespitosus or Streptomyces lavendulae. One of these compounds, mitomycin C, finds use as a chemotherapeutic agent by virtue of its antitumour activity. Mitomycin C has also been used topically rather than intravenously in several areas. The first is cancers, particularly bladder cancers and intraperitoneal tumours. It is now well known that a single instillation of this agent within 6 hours of bladder tumor resection can prevent recurrence. The second is in eye surgery where mitomycin C 0.02% is applied topically to prevent scarring during glaucoma filtering surgery and to prevent haze after PRK or LASIK; mitomycin C has also been shown to reduce fibrosis in strabismus surgery. The third is in esophageal and tracheal stenosis where application of mitomycin C onto the mucosa immediately following dilatation will decrease re-stenosis by decreasing the production of fibroblasts and scar tissue. Mitomycin C is a potent DNA crosslinker. A single crosslink per genome has shown to be effective in killing bacteria. This is accomplished by reductive activation of mitomycin to form a mitosene, which reacts successively via N-alkylation of two DNA bases. Both alkylations are sequence specific for a guanine nucleoside in the sequence 5'-CpG-3'. Potential bis-alkylating heterocylic quinones were synthetised in order to explore their antitumoral activities by bioreductive alkylation. Mitomycin is also used as a chemotherapeutic agent in glaucoma surgery.

Apaziquone (EOquin, EO9) is an indolequinone that is a bioreductive prodrug and a chemical analog of the older chemotherapeutic agent mitomycin C. In hypoxic cells, such as those on the inner surface of the urinary bladder, apaziquone is converted to active metabolites by intracellular reductases (such as NQO1). The active metabolites alkylate DNA and lead to apoptosis. In animal tumour models, EO9 was inactive against the P388 murine leukaemia but exhibited anti-tumour activity against human tumour xenografts and the generally chemo-resistant murine adenocarcinomas of the colon (MAC) tumours. Initial evidence that in vivo response correlated with NQO1 activity. Apaziquone was selected for clinical evaluation based upon its novel mechanism of action (which was distinct from MMC), its preferential activity against cells derived from solid tumours in vitro and in vivo, its ability to target both aerobic and hypoxic cells and the lack of myelosuppression in mice and rats. Apaziquone has been applied in clinical studies sponsored by Spectrum Pharmaceuticals and Allergan, Inc. for the treatment of superficial (non-muscle invasive) bladder cancer. However, the US-FDA determined that it was not statistically effective.

Arbutin, the beta-D-glucopyranoside of hydroquinone, is a skin whitening cosmetic ingredient. Compared with hydroquinone, arbutin is a less potent skin hyperpigmentation agent, but less toxic. Arbutin is found in a number of edible berry-producing plants such as blueberry and cranberry, marjoram, and most pear species. Chinchircoma (Muticia acuminatai) that contains arbutin, has been traditionally used by South American populations internally the fresh juice is used for gastric ulcers and internal tumors; the water of boiled leaves and flowers for illness of the respiratory tract; for hearth disorders or pain. According to pharmacological results in vitro, liver protective effects as well as anti-inflammatory activity were proven. It can also be beneficial for asthma and other anaphylactic reactions. This plant is component of the lsula Rain’s botanical products (Peru): ‘I-Day Digestive Cleanse #2.Herbal Supplement approved by FDA. As a hyperpigmentation agent arbutin inhibits tyrosinase and thus prevents the formation of melanin.

Apaziquone (EOquin, EO9) is an indolequinone that is a bioreductive prodrug and a chemical analog of the older chemotherapeutic agent mitomycin C. In hypoxic cells, such as those on the inner surface of the urinary bladder, apaziquone is converted to active metabolites by intracellular reductases (such as NQO1). The active metabolites alkylate DNA and lead to apoptosis. In animal tumour models, EO9 was inactive against the P388 murine leukaemia but exhibited anti-tumour activity against human tumour xenografts and the generally chemo-resistant murine adenocarcinomas of the colon (MAC) tumours. Initial evidence that in vivo response correlated with NQO1 activity. Apaziquone was selected for clinical evaluation based upon its novel mechanism of action (which was distinct from MMC), its preferential activity against cells derived from solid tumours in vitro and in vivo, its ability to target both aerobic and hypoxic cells and the lack of myelosuppression in mice and rats. Apaziquone has been applied in clinical studies sponsored by Spectrum Pharmaceuticals and Allergan, Inc. for the treatment of superficial (non-muscle invasive) bladder cancer. However, the US-FDA determined that it was not statistically effective.