Emtricitabine was discovered by Emory researchers Dr. Dennis C. Liotta, Dr. Raymond F. Schinazi and Dr. Woo-Baeg Choi and licensed to Triangle Pharmaceuticals by Emory University in 1996. Triangle was acquired by Gilead in 2003. Emtricitabine, marketed by Gilead as Emtriva, was first approved by the U.S. Food and Drug Administration in July 2003 for the treatment of HIV infection in combination with other antiretroviral agents. Emtricitabine, a synthetic nucleoside analog of cytidine, is phosphorylated by cellular enzymes to form emtricitabine 5'-triphosphate. Emtricitabine 5'-triphosphate inhibits the activity of the HIV-1 reverse transcriptase by competing with the natural substrate deoxycytidine 5'-triphosphate and by being incorporated into nascent viral DNA which results in chain termination.

Lamivudine is a reverse transcriptase inhibitor used alone or in combination with other classes of anti-human immunodeficiency virus (HIV) drugs in the treatment of HIV infection. This molecule has two stereo-centers, thus giving rise to four stereoisomers: (+/-)-cis-lamivudine and (+/-)-trans-lamivudine. The latter is considered to be impurity of the pharmaceutically active isomer, (-)-cis-lamivudine.

Methyl salicylate (or methyl 2-hydroxybenzoate), also known as wintergreen oil, is a natural product and is present in white wine, tea, porcini mushroom Boletus edulis, Bourbon vanilla, clary sage, red sage and fruits including cherry, apple, raspberry, papaya and plum. Methyl salicylate is topically used in combination with methanol and under brand name SALONPAS to temporarily relieves mild to moderate aches and pains of muscles and joints associated with: strains, sprains, simple backache, arthritis, bruises. The precise mechanism of action of methyl salicylate is not known, but there is suggested, that it cause dilation of the capillaries thereby increasing blood flow to the area.

(+)-cis-Lamivudine is an enantiomer of lamivudine, considered to be impurity. Lamivudine is a reverse transcriptase inhibitor used alone or in combination with other classes of anti-human immunodeficiency virus (HIV) drugs in the treatment of HIV infection.

Cytosine is a pyrimidine nucleobase, one of the five main bases of nucleic acids. In DNA and RNA cytosine is paired with guanine. Only small amounts of cytosine administered with food are incorporated in DNA. The majority of cytosine is synthesized de-novo starting from carbamoyl phosphate.

Uracil is a common and naturally occurring pyrimidine derivative, one of the four nucleobases in the nucleic acid of RNA In RNA, uracil binds to adenine via two hydrogen bonds. In DNA, the uracil nucleobase is replaced by it’s methylated form -- thymine. Originally discovered in 1900 by Alberto Ascoli, it was isolated by hydrolysis of yeast nuclein;[4] it was also found in bovine thymus and spleen, herring sperm, and wheat germ. It is a planar, unsaturated compound that has the ability to absorb light. Uracil readily undergoes regular reactions including oxidation, nitration, and alkylation. While in the presence of phenol (PhOH) and sodium hypochlorite (NaOCl), uracil can be visualized in ultraviolet light. Uracil also has the capability to react with elemental halogens because of the presence of more than one strongly electron donating group. Uracil readily undergoes addition to ribose sugars and phosphates to partake in synthesis and further reactions in the body. Uracil becomes uridine, uridine monophosphate (UMP), uridine diphosphate (UDP), uridine triphosphate (UTP), and uridine diphosphate glucose (UDP-glucose). Each one of these molecules is synthesized in the body and has specific functions. Uracil's use in the body is to help carry out the synthesis of many enzymes necessary for cell function through bonding with riboses and phosphates. Uracil serves as allosteric regulator and coenzyme for reactions in the human body and in plants. Uracil can be used for drug delivery and as a pharmaceutical. When elemental fluorine is reacted with uracil, 5-fluorouracil is produced. 5-Fluorouracil is an anticancer drug (antimetabolite) used to masquerade as uracil during the nucleic acid replication process. In combination with Tegafur, uracil used as a chemotherapy drug (called UFT or UFUR) used in the treatment of cancer, primarily bowel cancer. UFT is an anticancer medication composed of a fixed molar ratio (1:4) of tegafur and uracil to be administered with calcium folinate.

Abacavir is a nucleoside reverse transcriptase inhibitor used for treatment of HIV infection (either alone or in combination with other antiviral drugs). It was shown that abacavir exerts its antiviral activity through its active metabolite, carbovir triphosphate. Carbovir triphosphate is a guanine analogue and a potent and selective inhibitor of viral reverse transcriptases. Upon administration, abacavir is first converted to abacavir monophosphate by ADK, then the monophosphate is deaminated to carbovir monophosphate, which is then anabolized by cellular kinases to carbovir diphosphate and then finally to carbovir triphosphate. Abacavir causes hypersensitivity reaction in patients with HLA-B*57:01 allele.