RP‐HPLC Assay of Rofecoxib from Pharmaceutical Dosage Forms and Human Plasma and Its Drug Dissolution Studies

ABSTRACT

A high performance liquid chromatographic (HPLC) method is described for the determination of rofecoxib (RFC) in bulk drug, tablets, and human plasma samples. The methods are linear over the concentration ranges 0.005–30.0 and 0.010–10 µg mL⁻¹ in mobile phase and human plasma, respectively. Chromatography was carried out on a reversed phase Spherisorb ODSI column using a mixture of acetonitrile:methanol: 0.067 M KH₂PO₄ (27:20:53, v/v/v) adjusted to pH 6.95 with 3 M NaOH. Detection was realized at 244 nm using a DAD detector. The retention time observed for RFC and etodolac (internal standard) at about 7.5 and 10.7 min, respectively. The proposed RP‐HPLC method was validated for precision, accuracy, ruggedness, and recovery. The limit of detection was found to be 0.00143 and 0.00301 µg mL⁻¹ in mobile phase and human plasma samples, respectively. The proposed method allows a number of cost and time saving benefits. The described method can be readily applied for the analysis of tablets, drug dissolution studies, and human plasma samples. This method could be used without any interference from tablet matrix and endogenous substance from the plasma samples.

Keywords:

• Rofecoxib
• HPLC
• Tablets
• Human plasma
• Dissolution studies

Notes

^aMean values represent four different RFC standards for each concentration.

^bBetween‐day reproducibility was determined from four different runs over a 2 weeks period.

^a,bEach value is the mean of six experiments.

Note: kr, Release rate constant of first‐order kinetic; kr ⁰, release rate constant of zero‐order kinetic; k, release rate constant of Hixson–Crowell kinetic; kp, release constant of Peppas equation, r ², determination coefficient; SWSD, sum of weighed squared deviations; β, shape factor; T _(min), value stands for the time for 63.2% release of the drug; n, diffusional exponent.