Fast sample preparation for analysis of tablets and capsules: the ball-mill extraction method

A new ball-mill extraction method for solid dosage forms was developed. It was used for tablets, and compared with a conventional (powdering and sonication) method applied in pharmaceutical analysis of solid dosage forms. The ball-mill sample preparation procedure is both quantitative and fast. No powdering, weighing and sonication steps are needed in the sample preparation. The complete procedure takes 2 min (milling and extraction) and 5 min (centrifugation), respectively, much less than the conventional method in which sample preparation takes approximately 45–90 min. The samples are centrifuged in the mill vial, which saves time and avoids evaporation of solvent. Stainless steel extraction vials with different diameters were fabricated to enable the use of various extraction volumes. The extraction recovery was tested using various types of tablets (small, large and extended release tablets) with active compounds at low and higher concentrations, recoveries were comparable with the conventional method. The relative small investment and simplicity of the method makes it excellently suited for use in various pharmaceutical (development and quality assurance) laboratories.