Stability Indicating RP-HPLC Method for Simultaneous Determination of Atorvastatin and Nicotinic Acid from Their Combined Dosage Form

Abstract

The study describes development and subsequent validation of a stability indicating reverse-phase
HPLC method for simultaneous estimation of atorvastatin (ATR) and nicotinic acid (NTA) from their
combined dosage form. The proposed RP-HPLC method utilizes a Phenomenex® C18, 5 µm, 250 mm
X 4.6 mm i.d. column, at ambient temperature, optimum mobile phase consisted of acetonitrile and
50mM potassium dihydrogen phosphate buffer (68:32, v/v), apparent pH adjusted to 4.5±0.1 with
phosphoric acid solution, effluent flow rate monitored at 0.8 mL min-1, and UV detection at 247 nm.
The combination drug product are exposed to thermal, acid/base hydrolytic, humidity and oxidative
stress conditions, and the stressed samples were analyzed by proposed method. The described method
is linear over the range of 2-10 µg mL-1 and 20-100 µg mL-1 for ATR and NTA, respectively. The
mean recoveries are 100.99 and 102.65% for ATR and NTA, respectively. The intermediate precision
data obtained under different experimental setup, the calculated value of coefficient of variation
(CV,%) is found to be less than critical value. The limit of detection for ATR and NTA are found to be
0.16 and 0.12 µg mL-1, respectively. Chromatographic peak purity data of ATR and NTA indicated no
co-eluting peaks with the main peaks of drugs which demonstrated the specificity of assay method for
their estimation in presence of degradation products. The proposed method can be useful in the quality
control of combination drug products.