Cysteine (cysteine hydrochloride is a salt) is a thiol-containing amino acid that is oxidized to form cystine. Cysteine is synthesized from methionine via the trans-sulfuration pathway in the adult, but newborn infants lack the enzyme, cystathionase, necessary to effect this conversion. Therefore, cysteine is generally considered to be an essential amino acid in infants.

Droxidopa (Northera, Chelsea Therapeutics) is a synthetic catecholamino acid precursor of norepinephrine indicated for the treatment of orthostatic dizziness or lightheadedness in adult patients with symptomatic neurogenic orthostatic hypotension (NOH) caused by primary autonomic failure, dopamine beta-hydroxylase deficiency, and non-diabetic autonomic neuropathy. Droxidopa was approved as oral therapy in February 2014 under the FDA’s accelerated approval program. Droxidopa is directly metabolized to norepinephrine by dopadecarboxylase. The specific mechanism of action of the drug is not known completely, but it is supposed to exert the pharmacological effects through norepinephrine and not through the parent molecule or other metabolites. It increases blood flow to the brain by stimulating peripheral arterial and venous vasoconstriction.

Cyanocobalamin (commonly known as Vitamin B12) is the most chemically complex of all the vitamins. Cyanocobalamin's structure is based on a corrin ring, which, although similar to the porphyrin ring found in heme, chlorophyll, and cytochrome, has two of the pyrrole rings directly bonded. The central metal ion is Co (cobalt). Cyanocobalamin is naturally found in foods including meat (especially liver and shellfish), eggs, and milk products.Vitamin B12 is essential to growth, cell reproduction, hematopoiesis, and nucleoprotein and myelin synthesis. Cells characterized by rapid division (e.g., epithelial cells, bone marrow, myeloid cells) appear to have the greatest requirement for vitamin B12. Vitamin B12 can be converted to coenzyme B12 in tissues, and as such is essential for conversion of methylmalonate to succinate and synthesis of methionine from homocysteine, a reaction which also requires folate. In the absence of coenzyme B12, tetrahydrofolate cannot be regenerated from its inactive storage form, 5- methyltetrahydrofolate, and a functional folate deficiency occurs. Vitamin B12 also may be involved in maintaining sulfhydryl (SH) groups in the reduced form required by many SH-activated enzyme systems. Through these reactions, vitamin B12 is associated with fat and carbohydrate metabolism and protein synthesis. Vitamin B12 deficiency results in megaloblastic anemia, GI lesions, and neurologic damage that begins with an inability to produce myelin and is followed by gradual degeneration of the axon and nerve head. Cyanocobalamin is the most stable and widely used form of vitamin B12, and has hematopoietic activity apparently identical to that of the antianemia factor in purified liver extract. Parenteral (intramuscular) administration of vitamin B12 completely reverses the megaloblastic anemia and GI symptoms of vitamin B12 deficiency.

Panthenol (pantothenol) is an alcohol form of the B5 vitamin pantothenic acid. It easily penetrates the skin retaining water and is a humectant, emollient and moisturizer. Panthenol mitigates signs of inflammation and stimulates epithelization. Panthenol comes in two enantiomers, D and L. Only D-panthenol (dexpanthenol) is biologically active, however both forms have moisturizing properties. Because of the ability to attract and hold moisture panthenol is used in skincare products as a humectant. It also has a role as provitamin (called pro-vitamin B5) and is used as a vitamin supplement in complex ( M.V.I. ADULT injection, Hospira Worldwide, Inc.) and alone, and as a cholinergic drug. Panthenol is a highly viscous transparent liquid at room temperature, but salts of pantothenic acid (sodium pantothenate) are powders (typically white). It is soluble in water, alcohol, propylene glycol, ether and chloroform, and slightly soluble in glycerin. Panthenol mixes readily with many different types of ingredients, making it a versatile ingredient to be used in formulas because it improves skin’s barrier function and maintains the proliferation of fibroblasts. In organisms it is quickly oxidized to pantothenate (pantothenic acid). Defficiency of Vitamin B5 results in many dermatological disorder. Due to the fact that only D-Panthenol is converted to Vitamin B5 and not L-Panthenol, the racemic mixture of D- and L- panthenol (DL-panthenol) has only half of the physiological activity of the D-Panthenol. These include stimulation of epithelisation, wound healing effect and anti-infl ammatory effect. Panthenol is FDA approved for cosmetic use and comes either in D form, or as a racemic mixture. It is also in the FDA list of over-the-counter drug products that are not generally recognized as safe and effective or are misbranded: as "Insect Bite and Sting Drug Products" and "Poison Ivy, Poison Oak, and Poison Sumac Drug Products".

Pyridoxine is the 4-methanol form of vitamin B6 and is converted to pyridoxal 5-phosphate in the body. Vitamin B6 (pyridoxine) is a water-soluble vitamin used in the prophylaxis and treatment of vitamin B6 deficiency and peripheral neuropathy in those receiving isoniazid (isonicotinic acid hydrazide, INH). Vitamin B6 has been found to lower systolic and diastolic blood pressure in a small group of subjects with essential hypertension. Hypertension is another risk factor for atherosclerosis and coronary heart disease. Another study showed pyridoxine hydrochloride to inhibit ADP- or epinephrine-induced platelet aggregation and to lower total cholesterol levels and increase HDL-cholesterol levels, again in a small group of subjects. Vitamin B6, in the form of pyridoxal 5'-phosphate, was found to protect vascular endothelial cells in culture from injury by activated platelets. Endothelial injury and dysfunction are critical initiating events in the pathogenesis of atherosclerosis. Human studies have demonstrated that vitamin B6 deficiency affects cellular and humoral responses of the immune system. Vitamin B6 deficiency results in altered lymphocyte differentiation and maturation, reduced delayed-type hypersensitivity (DTH) responses, impaired antibody production, decreased lymphocyte proliferation and decreased interleukin (IL)-2 production, among other immunologic activities. Used for the treatment of vitamin B6 deficiency and for the prophylaxis of isoniazid-induced peripheral neuropathy.

Dimethyl maleate is an organic compound, the (Z)-isomer of the dimethyl ester of fumaric acid. Dimethyl maleate can be synthesized from maleic anhydride and methanol, with sulfuric acid acting as acid catalyst, via a nucleophilic acyl substitution for the monomethyl ester, followed by a Fischer esterification reaction for the dimethyl ester. Dimethyl maleate is used in many organic syntheses as a dienophile for diene synthesis. It is used as an additive and intermediate for plastics, pigments, pharmaceuticals, and agricultural products. It is also an intermediate for the production of paints, adhesives, and copolymers.

Sulfadiazine is a sulfonamide antibiotic. The sulfonamides are synthetic bacteriostatic antibiotics with a wide spectrum against most gram-positive and many gram-negative organisms. However, many strains of an individual species may be resistant. Sulfonamides inhibit multiplication of bacteria by acting as competitive inhibitors of p-aminobenzoic acid in the folic acid metabolism cycle. Bacterial sensitivity is the same for the various sulfonamides, and resistance to one sulfonamide indicates resistance to all. Most sulfonamides are readily absorbed orally. However, parenteral administration is difficult, since the soluble sulfonamide salts are highly alkaline and irritating to the tissues. The sulfonamides are widely distributed throughout all tissues. High levels are achieved in pleural, peritoneal, synovial, and ocular fluids. Although these drugs are no longer used to treat meningitis, CSF levels are high in meningeal infections. Their antibacterial action is inhibited by pus. Sulfadiazine is a competitive inhibitor of the bacterial enzyme dihydropteroate synthetase. This enzyme is needed for the proper processing of para-aminobenzoic acid (PABA) which is essential for folic acid synthesis. The inhibited reaction is necessary in these organisms for the synthesis of folic acid. Used for the treatment of rheumatic fever and meningococcal meningitis.

Niacin (also known as vitamin B3 and nicotinic acid) is bio converted to nicotinamide which is further converted to nicotinamide adenine dinucleotide (NAD+) and the hydride equivalent (NADH) which are coenzymes necessary for tissue metabolism, lipid metabolism, and glycogenolysis. Niacin (but not nicotinamide) in gram doses reduces LDL-C, Apo B, Lp(a), TG, and TC, and increases HDL-C. The increase in HDL-C is associated with an increase in apolipoprotein A-I (Apo A-I) and a shift in the distribution of HDL subfractions. These shifts include an increase in the HDL2:HDL3 ratio, and an elevation in lipoprotein A-I (Lp A-I, an HDL-C particle containing only Apo A-I). The mechanism by which niacin alters lipid profiles is not completely understood and may involve several actions, including partial inhibition of release of free fatty acids from adipose tissue, and increased lipoprotein lipase activity (which may increase the rate of chylomicron triglyceride removal from plasma). Niacin decreases the rate of hepatic synthesis of VLDL-C and LDL-C, and does not appear to affect fecal excretion of fats, sterols, or bile acids. As an adjunct to diet, the efficacy of niacin and lovastatin in improving lipid profiles (either individually, or in combination with each other, or niacin in combination with other statins) for the treatment of dyslipidemia has been well documented. The effect of combined therapy with niacin and lovastatin on cardiovascular morbidity and mortality has not been determined. In addition, preliminary reports suggest that niacin causes favorable LDL particle size transformations, although the clinical relevance of this effect is not yet clear. April 15, 2016: Based on several large cardiovascular outcome trials including AIM-HIGH, ACCORD, and HPS2-THRIVE, the FDA decided that "scientific evidence no longer supports the conclusion that a drug-induced reduction in triglyceride levels and/or increase in HDL-cholesterol levels in statin-treated patients results in a reduction in the risk of cardiovascular events" Consistent with this conclusion, the FDA has determined that the benefits of niacin ER tablets for coadministration with statins no longer outweigh the risks, and the approval for this indication should be withdrawn.

Phosphoric acid, also known as orthophosphoric acid, is used in dentistry and orthodontics to clean and roughen the surfaces of teeth where dental appliances or fillings will be placed. In addition, this acid is a part of product ProcalAmine, which is indicated for peripheral administration in adults to preserve body protein and improve nitrogen balance in well-nourished, mildly catabolic patients who require short-term parenteral nutrition. In combination with dextrose (glucose) and levulose (fructose), phosphoric acid relieves nausea due to upset stomach from intestinal flu, stomach flu, and food or drink indiscretions. In addition, homeopathic product, Brain power contains also phosphoric acid and this product is used to temporarily relieve symptoms of general physical weakness and listlessness, including: fatigue; sore muscles & joints; dry skin; absence of sexual desire; occasional sleeplessness.

Benzoic acid is a natural ingredient occurring in many foodstuffs and in plant extracts. Benzoic acid, its salts and esters are used as preservatives in cosmetic products, with a maximum concentration of 0.5 %. Benzoic acid and sodium benzoate are on the FDA list of substances that are generally recognized as safe (GRAS). Both may be used as antimicrobial agents, flavouring agents and as adjuvants with a current maximum level of 0.1% in food. Benzoic acid is a constituent of Whitfield Ointment, which is used for the treatment of fungal skin diseases such as tinea, ringworm, and athlete's foot. Adverse effect of Whitfield Ointment: occasionally, a localized mild inflammatory response occurs.