Sample Preparation Trends in Pharmaceutical Analysis

As stated earlier, the SP trend in the pharmaceutical analysis of solid dosage forms is dominated by manual batch techniques such as grinding, sonication, dilution in volumetric flask and filtration. The unique SP requirements for solid dosages in grinding and handling large volumetries are particularly difficult to automate. 

The application of robotics to enhance laboratory productivity has met with some success with many early adapters and in laboratories with high-volume repetitive routine assays. However, the requirements for extensive installation, development, validation and continuing maintenance effort have slowed the growth of robotics in pharmaceutical laboratories. Many robots in pharmaceutical R D labs have been abandoned or mothballed because they were not sufficiently flexible or reliable at 

This case study illustrates the SP method development of an assay method for a controlled-release analgesic tablet with a single API. Certain considerations were taken into account. First, the analyte within the tablet matrice core had to be extracted quantitatively. Second, the analyte was diluted into a final solution that was compatible with the HPLC mobile phase. Third, short SP time was required (i.e., 30 min) to maximize productivity of the work scheme for processing a large number of samples. 

The drug substance was a water-soluble base in salt form with a pK of about 9 that was also soluble in most organic solvents. The polymer in the tablet was, however, soluble only in an organic medium like methanol. Other organic solvents such as acetonitrile and dimethylformamide were 

Transfer 10 tablets into a 500-mL volumetric flask and add approximately 200mL of methanol. 

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