OPTIMIZATION OF RP-HPLC METHOD BY 32 – CENTRAL COMPOSITE DESIGN FOR THE VALIDATION AND ESTIMATION OF DOXYCYCLINE HYCLATE IN BULK DRUG AND FORMULATIONS

An accurate, sensitive, precise, economic and rapid isocratic Reverse Phase High Performance Liquid Chromatography method was developed complying Quality by Design (QbD) trends and validated for determining doxycycline hyclate in bulk drug, tablet and capsule dosage form. The method was optimized using Minitab software with 3 factors (pH of the buffer, flow rate and percentage of buffer in the mobile phase), 2 level (higher limit and lower limit) Central Composite Design (CCD). The results of randomized 20 runs were analyzed for optimum composite desirability to give optimum conditions such as, pH 6.5, flow rate 0.9 mLmin-1 and 30:70 V/V 0.05M potassium dihydrogen orthophosphate buffer adjusted to pH 6.5 using orthophosphoric acid and methanol using C8 column 250 X 4.6 mm X 5.0 μm, injection volume of 10uL, ambient column temperature and ultraviolet detection using photo diode array detector at 360nm as constants. The method was validated as per ICH guidelines and was found linear over a concentration range of 10-100 μg/mL (r2 = 0.999) with the limits of detection and quantification being 2.45 μg/mL and 7.55 μg/mL respectively.