Chemical compounds can exist in three basic phases: gaseous, liquid, or solid. In gaseous form, chemicals are comprised of weakly bonded atoms that are able to expand to fill any available space. Liquids, however, are slightly more structured than gases, the component parts that comprise them moving freely among themselves, but tending not to disperse and separate from one another. Solid compounds, which exhibit strong atomic bonding, are the most structured type of chemicals, featuring a rigid shape and a definite volume. Furthermore, many solids exist naturally as crystals, their atoms displaying distinct three-dimensional geometrical patterns. Advances in science and technology have also made it possible to create a tremendous array of artificial crystals in the laboratory, a feat that has many important commercial and industrial applications.

Acetaminophen - Similar to aspirin, acetaminophen can be utilized to treat a variety of aches, pains, and minor ailments. Though the exact processes involved are not fully understood, the compound is generally believed to provide temporary relief for such conditions by hindering the synthesis of substances necessary for the conduction of pain impulses through the body. Acetaminophen can also help reduce fevers by acting upon the temperature-regulating region of the brain, but does not possess any significant anti-inflammatory properties.

Ampicillin - The chief advantage of ampicillin over other types of penicillin is the relative stability of the substance in the stomach. Due to this important characteristic, the antibiotic may be administered orally, usually as a capsule, liquid, or pediatric drop. The ease with which this may be done has resulted in the drug’s immense popularity, it finding use in the treatment of a number of respiratory and urinary-tract infections, as well as bacterial meningitis, typhoid fever, and similar illnesses.

Anthranilic Acid - The former status of anthranilic acid as a vitamin stemmed from work carried out by a Japanese research group working in the 1930s. Led by Dr. W. Nakahara, the group successfully isolated two distinct factors that were believed to be essential for the lactation of female rats. Dubbing them “vitamin L,” the researchers proposed that the factors were essential to the metabolism of humans. Through additional studies, it was determined that the factor L(1), which was extracted from the liver of a bovine calf, was anthranilic acid, while the second factor, which was extracted from yeast, was demonstrated to be adenyl thiomethylpentose.

Atropine - Chemically similar in some regards to acetylcholine, within the body, atropine interferes with the nerve impulses normally conveyed by the neurotransmitter. The effects resulting from this action are numerous and diverse. Inhibition of the vagus nerve, for instance, usually causes an increase in heart rate, while the relaxation of smooth muscle comprising the bronchial tubes as well as the drying of saliva and nasal secretions clear the air passages and make breathing easier. Atropine also eases spasms in the intestines and dilates the pupils.

AZT - When AZT, also known as zidovudine and azidothymidine, was first manufactured, it was intended for use as an anti-cancer drug, but never received approval from the United States Food and Drug Administration (FDA) for that function. In the mid-1980s, however, it became one of the first pharmaceuticals approved to treat the human immunodeficiency virus (HIV), which causes AIDS. In fact, the typical 8 to 10 years of trials and studies that are usually associated with FDA approval of a new drug were significantly reduced for AZT.

Benzeneboronic Acid - Today, the life science and pharmaceutical fields are developing at an amazing pace. In order to carry on such an impressive rate of drug discovery and development, a number of chemical compounds have been created to facilitate organic synthesis and chemistry. Among the most important of these compounds are boronic acids, such as benzeneboronic acid, naphthaleneboronic acid, and trifluoromethylbenzeneboronic acid, which act as versatile chemical precursors from which a wide range of chemical substances may be built.

Beta-Carotene - In 1831, beta-carotene was first isolated from the roots of carrots, but it was not until the Nobel prize-winning research of Paul Karrer in the early 1930s that the structure of the substance was determined. The earliest use of synthesized beta-carotene was as a food colorant, but during the 1980s the vitamin precursor’s growing reputation as an antioxidant and a possible cancer-fighter resulted in its frequent inclusion in vitamin supplements. Since that time, however, conflicting findings about the benefits of taking synthesized beta-carotene have surfaced.

Biotin - Biotin serves an array of functions in the human body, but is particularly important for metabolism of fats, carbohydrates, and amino acids. However, the necessary daily intake of the vitamin, which is typically believed to be 100 to 200 micrograms for adults, is quite low. Thus, naturally occurring biotin deficiencies are extremely rare. When deficiencies of the vitamin do occur it is usually due to one of two different genetic enzyme disorders that effectively result in an increase of the bodily requisite for biotin.

Caffeine - In addition to coffee, caffeine occurs naturally in tea, kola nuts, and ilex plants, as well as cocoa in small amounts. The substance can, however, also be prepared synthetically from uric acid and added to various consumables. In pure form it is odorless, somewhat bitter in taste, white, powdery, and soluble in water. The substance is also rapidly absorbed by the body, which distributes the caffeine through all of its tissues and fluids, producing a stimulating effect on the central nervous system, heart, kidneys, and blood vessels.

Chloroisatin - Chloroisatin is a chemical intermediate that usually appears in the form of a yellowish-red crystal. One of several different isatins currently available, chloroisatin is a versatile substrate that can be utilized to synthesize a wide range of heterocyclic compounds, such as quinolines and indoles. The chemical intermediate also frequently finds use as a raw material for pharmaceutical synthesis and has been recently involved in efforts to create new anticonvulsant drugs.

Cholesterol - As is commonly known, excessive levels of cholesterol in the blood are considered a key cause of atherosclerosis and heart disease. However, the arteriosclerotic deposits, which may accumulate in the blood vessels and impede circulation, are chiefly comprised of cholesterol attached to LDLs, while HDLs may actually function to retard or reduce such buildups. Thus, individuals that have low high-density lipoprotein levels may be at greater health risk than those with higher levels.

Clozaril - There is a certain amount of hesitation in the medical field to prescribe clozaril to any but the most severe sufferers of schizophrenia. This reluctance is due to the serious side effects associated with the drug, which include seizures, decreased blood pressure, accelerated heart rate, myocarditis, and agranulocytosis, or a dangerously reduced white blood cell count. Moreover, a number of more standard drug therapies are often utilized before clozaril is recommended in hopes that treatment with the antipsychotic medication will not be necessary.

DDC (2’,3’-Dideoxycytidine) - A nucleoside reverse transcriptase inhibitor commonly utilized in HIV treatment is 2’,3’-dideoxycytidine, typically abbreviated DDC or ddC. The medication, which is also known by the trade names Zalcitabine and Hivid, can help slow the destruction of the human immune system by blocking HIV reverse transcriptase during the early stage of viral replication through attachment to the enzyme. Thus, production of new HIV within the body is prevented by interference with DNA replication in viral cells, resulting in a subsequent decrease in the bodily amount of the virus.

DDI (2',3'-Dideoxyinosine) - DDI is a synthetic purine nucleoside that acts as a reverse transcriptase inhibitor. As such, the drug may prevent further reproduction of HIV viral cells, but does not affect existing cells. Studies indicate that DDI may also cause an increase in the number of CD4 helper white blood cells in the body, functioning to counteract the depressed counts associated with advanced stages of HIV. However, due to the severe nature of some side effects associated with the drug, when the United States Food and Drug Administration (FDA) initially approved DDI for the treatment of HIV/AIDS in 1991, it was designated solely for use after prolonged AZT treatments.

DDT - Though a German graduate student first synthesized it in 1873, DDT was not used as an insecticide until it was rediscovered by Dr. Paul Mueller, a Swiss entomologist searching for a long-term solution to the clothes moth, in 1939. When further research demonstrated that the synthetic chlorinated hydrocarbon was also effective against flies, lice, and mosquitoes, the military realized its potential for protecting troops against insect-borne diseases during World War II. Then, in 1948, after the substance was credited with staving off countless outbreaks of malaria, typhus, and related illnesses, Mueller was awarded the Nobel Prize in medicine.

Dimethoxyhydroxycinnamic Acid - Sometimes alternatively known as sinapinic acid, dimethoxyhydroxycinnamic acid is often used as a matrix material in matrix-assisted laser ionization. The yellow-brown crystalline powder, which melts at about 203 degrees Celsius, is just one of many derivatives of cinnamic acid that have been introduced for this and other purposes. Cinnamic acid is derived from the amino acid phenylalanine and may be extracted from plants for use or synthesized in the laboratory.

Ephedrine - In the United States, ephedrine is sold under a variety of trade names, usually as a component of over-the-counter drugs intended to treat congestion, coughing, wheezing, and related symptoms of asthma, bronchitis, and lung disease. The alkaloid achieves its effect on the body primarily through the discharge of excitatory chemicals called catecholamines. The catecholamines, which act upon cellular receptors, effectively stimulate lipolysis, dilate the bronchioles, accelerate the heart rate, increase alertness, and often diminish one’s appetite.

Erythromycin - First isolated from the soil fungus Streptomyces erythraeus in 1952 by a team of researchers led by American scientist J. M. McGuire, erythromycin is most successful at fighting gram-positive bacteria, though it also exhibits some action against some types of gram-negative bacteria. The macrolide antibiotic is believed to function within the body by binding to certain ribosomal subunits in susceptible bacteria, the result of which is a suppression of protein synthesis.

Estrone - Estrone was first isolated in 1929 by American biochemist Edward Adelbert Doisy, who later isolated estriol (1930) and estradiol (1935) as well. These notable achievements were an important step towards the development of oral contraceptives, which are largely composed of estrogens. The reason that these hormones are effective for such an application is that they inhibit the pituitary gland’s secretion of follicle-stimulating hormone and can, consequently, suppress ovulation.

Folic Acid - Folic acid was initially isolated from spinach leaves, an event that resulted in its common name, which is derived from the Latin word folium, meaning “leaf.” The vitamin was first produced synthetically in 1945, and since that time has been included in a wide array of supplements and many fortified foods, such as cereals. These items have played an important role in ensuring that individuals regularly consume the recommended dietary allowance of folic acid, which is 400 micrograms for adults.

Glutamic Acid - First isolated in 1865, glutamic acid is one of only two amino acids that exhibit a net negative charge at physiological pH, a characteristic that stems from a carboxylic acid moiety on the side chain of the molecule. This negative charge makes glutamic acid a very polar molecule. Consequently, the amino acid is usually found on the outside of proteins and enzymes where it is free to interact with the aqueous intracellular milieu.

Glutaric Acid - Glutaric acid, which is isomeric with pyrotartaric acid, has the lowest melting point of all dicarboxylic acids and is highly soluble in water. Also, the structure of the substance helps facilitate the creation of polymer resins that are more elastic than those formed with many other materials. Due to these and other beneficial characteristics, glutaric acid is utilized as a resin intermediate and for a variety of other applications. The substance is, for instance, often a component in cleaning products and detergents, plasticizers, and pharmaceuticals.

Liquid Crystalline DNA - DNA is found in all prokaryotic and eukaryotic cells, as well as in a number of viruses. The molecule carries the chemical information that is essential for the direction of protein synthesis and cell replication. In human cells, DNA is wrapped around a complex of histone proteins, forming what is known as chromatin. Chromatin undergoes a process of condensation for cell division or the production of gametes, developing into the higher-order structures called chromosomes. Only one human DNA molecule is present per chromosome.

Malonic Acid - Water-soluble, white, and crystalline, malonic acid, which is readily decomposed by heat and relatively unstable in its free form, has little practical use other than acting as a biochemical diagnostic probe for intermediary metabolism. The substance’s diethyl ester, however, is commonly utilized to synthesize barbiturates, vitamins B1 and B6, and various other compounds. The ester is created through a reaction of ethyl alcohol and cyanoacetic acid.

Miconazole - A variety of treatments for fungal infections have been developed over the years, some of which are systemic and others that are normally utilized topically. One of the most popular topical antifungal agents is miconazole, which is available in both over-the-counter and prescription strengths under a variety of trade names, including Micatin and Monistat. Among the conditions that are commonly treated with miconazole are ringworm, athlete’s foot, tinea versicolor, jock itch, and yeast infections.

Mycostatin - Mycostatin is a brand name for the generic drug nystatin, which was first developed by New York Department of Health researchers Elizabeth Lee Hazen and Rachel Fuller Brown. Since it was patented in 1957, the antifungal antibiotic has helped cure countless humans suffering from a variety of fungal infections, such as thrush and intestinal candidiasis. In addition, nystatin has been utilized for a number of less well-known applications, such as treatment of Dutch Elm’s disease and the restoration of artwork damaged by mold.

Naphthaleneboronic Acid - Accounts of the medicinal use of plants and minerals date back to antiquity, but the pharmaceutical profession is generally believed to have originated in 1617, when the Society of Apothecaries was established in London. Since that time, a tremendous array of pharmaceuticals has been developed through a wide variety of means. Some of the earliest pharmaceuticals put into use were anesthetics, such as morphine, ether, and chloroform, all of which were developed in the first half of the nineteenth century.

Nicotine - Despite its seemingly benign effects in small doses, larger quantities of nicotine are highly toxic and may cause dizziness, headaches, vomiting, stomach pain, and, in extreme cases, convulsions and death. Nicotine may also have long-term adverse effects on one’s health and is physiologically addictive. The addictiveness of nicotine is the reason why most smokers who attempt to quit suffer withdrawal symptoms and, often, a relapse. Some products, such as Nicoderm, Nicorette, and ProStep, attempt to ease this transition through topical or systemic intake of nicotine.

Nicotinic Acid - Involved in various functions within the body, nicotinic acid aids in red blood cell formation, plays an active role in more than 50 different enzymatic reactions, and is considered necessary to maintain the health of the skin and digestive tract. Consequently, a dietary deficiency of the vitamin is primarily characterized by digestive disturbances and skin lesions. Known as pellagra, this condition may also lead to dementia in severe or prolonged cases.

Pantothenic Acid - Essential for animal metabolism, pantothenic acid plays a variety of roles within the body. It is, for instance, a basic component of coenzyme A and is involved in the decarboxylation of pyruvate in the citric acid cycle. The vitamin is also necessary for the bodily production of red blood cells and steroid metabolism, as well as the stimulation of antibody synthesis and proper neuron activity. Some of the many dietary sources of pantothenic acid include yogurt, mushrooms, eggs, lentils, meats, soybeans, and wheat germ.

Para-Aminobenzoic Acid (PABA) - PABA has been most often utilized by humans as a component in sunscreens, successfully protecting the skin from harmful ultraviolet radiation. However, the frequent occurrence of PABA-related skin irritations has led many companies to introduce suntan oils and lotions that are PABA-free. Many people may also be familiar with ethyl-PABA, more commonly known as benzocaine, the key ingredient in many pain and itch relief ointments.

Progesterone - Synthetic derivatives of progesterone, often referred to as progestins, are commonly utilized in oral contraceptives, Depo-Provera, and other birth control methods. Progestins, which may help reduce the risk of some cancers, are also frequently prescribed to women suffering from undesirable effects associated with menopause. Yet, administration of synthetic progesterone may itself be problematic at times, occasionally contributing to the development of blood clots, cardiovascular problems, and decreased levels of high-density lipoprotein.

Retinoic Acid - An essential part of the human diet, retinoic acid is involved in a variety of bodily functions. The substance, for instance, plays a part in the embryonic development of the hindbrain and faciocranial nerves, as well as the differentiation of neurons. Maintenance of healthy skin, hair, mucous membranes, bones, and teeth, are also facilitated by retinoic acid. In fact, the biochemical, which is believed to increase the rate of cell division and turnover, is often used topically in skin-improvement treatments.

Riboflavin - Riboflavin derives its name from the Latin word for “yellow,” an indication of the lush color of crystals formed from the pure vitamin. Biochemically, the substance, which is metabolized to form the coenzymes flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), is involved in an array of bodily functions, such as the breakdown of fats and the syntheses of red blood cells, steroids, and glycogen. Approximately 1.2 to 1.7 milligrams of riboflavin a day is believed to be sufficient to successfully sustain such activities in the adult body.

Succinimide - Succinimide is a diketopyrrolidine that is prepared by rapid distillation of ammonium succinate. It and other modern anticonvulsants commonly utilized to treat epileptics generate their beneficial effects by acting on the central nervous system, which generally reduces the severity and frequency of seizures. Obtainable only by prescription and often more commonly known by the brand names Celontin and Zarontin, succinimide is available in both capsule and syrup form for oral consumption.

Tacrine - In 1993, tacrine became the first pharmaceutical approved by the United States Food and Drug Administration to treat Alzheimer’s disease, the most common form of dementia in the world. Often better known by the trade name Cognex, the drug cannot cure or prevent the degenerative brain disorder, but can improve the cognitive ability of some of its sufferers, especially if they are not yet in an advanced state of the disease. Tacrine achieves its effect in the body by slowing the breakdown of the chemical messenger acetylcholine, which is heavily associated with learning and memory processes.

Taxol - Taxol, which is initially harvested in the form of a white powder, appears as a colorless liquid when it is prepared for medical use. This liquid is provided to patients intravenously, usually once every three weeks. The drug, which is most commonly utilized for treatment of ovarian, breast, lung, and testis cancers, interferes with the process of mitosis within the body, stemming the uncontrolled cell proliferation associated with tumor growth. Taxol does often produce, however, a number of undesirable side effects, many of which are similar to those generated by chemotherapy.

Testosterone - Testosterone is the primary male sex hormone, but is also found in women, though in much smaller amounts. An average man, for instance, may contain as many as 1,000 nanograms of testosterone in a deciliter of blood plasma, while a typical female does not usually exhibit more than 60 nanograms of the hormone in the same amount of plasma. The location of testosterone production is also different between the sexes, males producing the substance primarily in the testes and females manufacturing it in the ovaries and adrenal glands.

Trifluoromethylbenzeneboronic Acid - Boronic acids, which are stable in air, easy to handle, and form nontoxic byproducts, are most heavily utilized in Suzuki coupling reactions that quickly and effectively form carbon-carbon bonds, an essential step in innumerable chemical reactions. The development of these acids has significantly affected the life science and pharmaceuticals industries, since they act as versatile chemical precursors from which a wide array of chemical compounds may be built.

Urea - Although the greatest concentration of urea within the body is found in the urine, the nitrogenous substance also occurs in the blood, bile, and perspiration, as well as the milk of lactating females. The substance is periodically excreted in the urine, but reaccumulates during protein metabolism, when amino groups are removed from the amino acids of proteins and are converted to ammonia. Since ammonia is toxic, the body quickly converts the compound to urea by filtering it through the liver.

Uridine - Uridine is one of four nucleosides used in genetic coding for RNA, and its complement is the nucleoside adenosine. The melting point of purified crystalline needles of uridine, which are soluble in water, is 165 degrees Celsius. Within the body, the nucleoside plays an important role in the metabolism of carbohydrates, and, in the laboratory, the white odorless powder that can be extracted from yeast ribonucleic acids using a weak alkali solution is utilized in a variety of biochemical experiments and studies.

Viagra - Viagra is the trade name of sildenafil citrate, a synthetic heterocyclic piperazine derivative marketed by Pfizer, Incorporated. Within the body, the drug acts by selective inhibition of cyclic guanosine monophosphate (cGMP) phosphodiesterase type 5, which facilitates the relaxation of smooth muscles and an influx of blood to the corpus cavernosum. The production of these conditions typically results in erection during sexual stimulation. In fact, studies indicate that as many as four out of five men suffering from impotence are restored sexual function when Viagra is taken, no matter what originally caused the dysfunction.

Vitamin B6 - Vitamin B6 is found in a wide variety of foods, including meats, corn, nuts, soybeans, wheat germ, oats, and molasses. Exposure to sunlight or heat can, however, decrease the natural levels of the vitamin in these items. The United States Food and Drug Administration’s Recommended Dietary Allowance (RDA) of the vitamin is 2 milligrams, but the effects of consuming inadequate amounts of it are rather non-specific, dependent on other factors in the diet, and difficult to reproduce.

Vitamin B12 - It is generally agreed that adults should consume approximately 3 micrograms of vitamin B12 daily. Since plants are unable to synthesize the substance, they are not a good source of the vitamin. However, animal tissues, such as the liver and kidneys of cows and other ruminants, may contain significant quantities of the biochemical although they are also unable to synthesize the vitamin. This is because microorganisms in the gut of ruminants produce vitamin B12 and it is then transported to other tissues.

Vitamin C - Within the human body, vitamin C is involved in a number of key activities. One of the most important of these activities is assisting in the production of collagen, the primary protein utilized to synthesize connective tissue, which is necessary for proper bone, skin, and cartilage formation. Vitamin C, which is also known as ascorbic acid, is a critical antioxidant and free radical scavenger as well, though its effectiveness as an antiviral agent is debatable. Due to the importance of its functions, vitamin C intake is necessary for humans on a regular basis since it quickly passes through the body.

Vitamin D - The United States Food and Drug Administration’s Recommended Dietary Allowance (RDA) of vitamin D is 10 micrograms for men, women, and children. Most people are able to easily obtain such a dosage through regular exposure to sunlight, which reacts with the vitamin D precursor, 7-dehydrocholesterol, present in the skin to produce adequate levels of the vitamin. In some northern locations during winter or areas suffering from severe air pollution, however, individuals may not come into contact with enough ultraviolet rays to produce sufficient quantities of vitamin D.

Vitamin E - Vitamin E is present in significant amounts in a wide variety of foods, such as nuts, wheat germ oil, whole grains, green leafy vegetables, vegetable oils, and eggs. In fact, the ubiquity of vitamin E makes naturally occurring deficiencies of the vitamin extremely rare. However, the symptoms of such a deficiency can be relatively serious. Most often mild anemia and a decreased level of the lipid-soluble compounds known as tocopherols in the blood plasma occur. However, in chronic cases, ataxia, pigmentary alteration of the retina, and the improper absorption of fats also frequently transpire.

Vitamin K3 - While a vitamin K deficiency can be dangerous, especially to infants that may easily suffer from extensive hemorrhaging, an overdose can be as equally detrimental. Newborns that are administered too great a dosage of vitamin K3 can suffer from kernicterus, a form of severe brain damage that may produce decreased movement, loss of appetite, seizures, deafness, mental retardation, and even death. This condition is associated with an abnormally high concentration of bilirubin, a bile pigment, in the tissues of the brain, which can be caused by the presence of K3.