Sildenafil citrate is the chemical name and active ingredient in the brand-name drugs, Viagra and Revatio, which are marketed by the pharmaceutical company, Pfizer. Sildenafil was approved as Viagra in 1998 by the U.S. Food and Drug Administration to treat erectile dysfunction, and in 2005 as Revatio to treat hypertension, according to Drugs.com. Sildenafil products also contain many components, most of them inactive.
Sildenafil Citrate
According to DrugLib.com, sildenafil citrate is the active ingredient in sildenafil products such as Viagra and Revatio. It enhances the effect of nitric oxide by selectively inhibiting the enzyme phosphodiesterase type 5, which causes increased levels of cyclic guanosine monophosphate in the brain’s corpus cavernosum, resulting in smooth muscle relaxation and increased blood flow to the penis, as well as reduced blood pressure. Thus, Viagra is used to treat impotence in men, while Revatio is used to treat high blood pressure and improve exercise capacity in both men and women.
Binding and Filling Components
According to DailyMed, sildenafil products contain four components that can be labeled as binders and fillers: microcrystalline cellulose, hypromellose, monohydrate lactose and anhydrous calcium phosphate. Binders keep the ingredients intact and ensure that tablets/pills can be formed under the pressures of the compounding process. Binders are usually sugars, cellulose or cellulose derivatives. The cellulose, lactose and phosphate compounds also act as fillers, which make the tablet bigger, making it practical for manufacturing and convenient for the consumer to handle and use, according to the Dictionary of Pharmaceutical Medicine. Fillers are chemically inert, compatible with other ingredients, water soluble, colorless and tasteless.
Disintegrating Component
Sildenafil products also contain croscarmellose sodium, which acts primarily as a filler in pharmaceuticals. It also helps with quick disintegration of the medication and better absorption by the lower intestines, according to the Dictionary of Pharmaceutical Medicine. Specifically, it’s a cross-linked methyl cellulose compound that absorbs water and aids in the absorption of the medication’s active ingredient, sildenafil citrate.
Lubricants and Mixing Components
Magnesium stearate is another component in sildenafil products, and acts as both a lubricant and stabilizer in the compounding process of drug manufacturing. Magnesium stearate combines with another ingredient, triacetin, to help mix the ingredients evenly, according to the Dictionary of Pharamceutical Medicine. Triacetin is a simple fatty acid that is a common food additive and also used as a solvent. Lubricants assist with the flow of powdered ingredients through production and help prevent them from sticking to the equipment.
Coloring Components
All Viagra tablets, regardless of dosage, contain FD&C blue No. 2 dye, giving them the characteristic blue appearance, according to DailyMed. Revatio pills contain no ferric oxides or dyes, which leaves them white in color. Titanium dioxide is used in both products because of its ability to provide brightness and opacity to either tablets or pills.
References
- “Dictionary of Pharmaceutical Medicine”; G. Nahler et al; 2009
- Drugs.com: Revatio / Sildenafil
- RxList.com: Viagra / Sildenafil
- DrugLib.com: Viagra
- DailyMed: Viagra / Revatio Ingredients
