Naropin (ropivacaine HCl Injection) is a member
of the amino amide class of local
anesthetics. Naropin injections are sterile,
that contain the enantiomerically proof
drug substance, sodium
chloride for isotonicity
and Water for Injection. Sodium hydroxide
and/or hydrochloric acid may be used for pH
adjustment. These solutions are administered parenterally.
Naropin contains ropivacaine HCl which is chemically described
as S-(-)-1-propyl-2',6'-pipecoloxylidide hydrochloride monohydrate.
The drug substance
is a white crystalline
powder, with a chemical
formula of C17H26N2O·HCl·H2O
and molecular weight
At 25°C ropivacaine HCl has a solubility
of 53.8 mg/mL in water, a distribution
ratio between n-octanol
and phosphate buffer
at pH 7.4 of 141 and a pKa
of 8.07 in 0.1 M KCl solution.
The pKa of ropivacaine is approximately the same as bupivacaine
(8.1) and is similar to that of mepivacaine (7.7). However, ropivacaine
has an intermediate
degree of lipid solubility
compared to bupivacaine and mepivacaine.
Naropin is preservative
free and is available in single dose
containers in 2.0, 5.0, 7.5 and 10.0 mg/mL concentrations. The specific
gravity of Naropin solutions
range from 1.002 to 1.005