Hepatitis B Virus
Chemical Data: The chemical name for entecavir is 2-amino-1,9-dihydro-9-[(1S,3R,4S)-4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopentyl]-6H-purin-6-one. Its molecular formula is C12H15N5O3, which corresponds to a molecular weight of 277.12 g/mol (Figure 5). At room temperature, entecavir is a white to off-white powder. It is slightly soluble in water (2.4 mg/mL), and the pH of the saturated solution in water is 7.9 at 25°C ± 0.5°C. Entecavir is administered orally in tablet form. It is available in strengths of 0.5 mg and 1 mg.