Sildenafil (Viagra, Revatio) is a PDE5 inhibitor which was approved by FDA for the treatment of erectile disfunction and adults with pulmonary arterial hypertension. Upon administration sildenafil inhibits PDE5 and results in elevated level of cyclic guanosine monophosphate and smooth muscle relaxation.

Potassium citrate is indicated for the management of renal tubular acidosis with calcium stones, hypocitraturic calcium oxalate nephrolithiasis of any etiology, uric acid lithiasis with or without calcium stones. WhenPotassium citrate is given orally, the metabolism of absorbed citrate produces an alkaline load. The induced alkaline load in turn increases urinary pH and raises urinary citrate by augmenting citrate clearance without measurably altering ultrafilterable serum citrate. Thus, potassium citrate therapy appears to increase urinary citrate principally by modifying the renal handling of citrate, rather than by increasing the filtered load of citrate. Potassium citrate is used as a food additive (E 332) to regulate acidity.

Imidazole is a planer five-member heterocyclic ring with 3C and 2N atom and in ring N is present in 1st and 3rd positions. The imidazole ring is a constituent of several important natural products, including purine, histamine, histidine and nucleic acid. Being a polar and ionisable aromatic compound, it improves pharmacokinetic characteristics of lead molecules and thus used as a remedy to optimize solubility and bioavailability parameters of proposed poorly soluble lead molecules. The imidazole derivatives possess extensive spectrum of biological activities such as antibacterial, anticancer, antitubercular, antifungal, analgesic, and anti-HIV activities. The organic compound is used in the chemical industry as an intermediate in the production of pharmaceuticals, pesticides, dye intermediates, auxiliaries for textile dyeing and finishing, photographic chemicals and corrosion inhibitors. The chemical possesses properties (corrosivity to skin, irreversible damage to eyes, teratogenic effects) indicating a hazard for human health. Humans are exposed by consumer products (chemical concentrations up to 10%) and at the workplace. Therefore, the chemical is a candidate for further work. An exposure assessment and if indicated a risk assessment is recommended.