Valacyclovir description

VALTREX (valacyclovir hydrochloride) is the hydrochloride salt of the L─valyl ester of the antiviral drug acyclovir.

VALTREX Caplets are for oral administration. Each caplet contains valacyclovir hydrochloride equivalent to 500 mg or 1 gram valacyclovir and the inactive ingredients carnauba wax, colloidal silicon dioxide, crospovidone, FD&C Blue No. 2 Lake, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, povidone, and titanium dioxide. The blue, film─coated caplets are printed with edible white ink.

The chemical name of valacyclovir hydrochloride is L-valine, 2-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl)methoxy]ethyl ester, monohydrochloride. It has the following structural formula:

Valacyclovir hydrochloride is a white to off─white powder with the molecular formula C13H20N6O4•HCl and a molecular weight of 360.80. The maximum solubility in water at 25°C is 174 mg/mL. The pkas for valacyclovir hydrochloride are 1.90, 7.47, and 9.43.^[1]

Adapted from the FDA Package Insert.