RUGGEDNESS TESTS ON THE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY ASSAY OF THE UNITED-STATES-PHARMACOPEIA-XXII FOR TETRACYCLINE HYDROCHLORIDE - A COMPARISON OF EXPERIMENTAL-DESIGNS AND STATISTICAL INTERPRETATIONS

Ruggedness tests were performed for the high-performance liquid chroma tographic method for the determination of tetracycline hydrochloride f rom the United States Pharmacopeia XXII using Plackett-Burman and frac tional factorial designs. Different statistical interpretation criteri a for both kinds of designs were compared. The interpretation criteria for the Plackett-Burman designs were based on the use of dummy factor s in the design and for the fractional factorial designs on two-factor interaction effects. The statistical interpretation criteria were com pared with graphical ones (e.g., normal probability plots). The result s of the designs (the ruggedness tests) were interpreted based on the above criteria. Other potential alternatives for statistical interpret ation were also examined. Two different types of stationary phases (C- 8 and C-18) were tested and compared.