Simultaneous determination of alpha-, beta- and gamma-hydroxybutyric acids in micro-pulverized human hair by GC-MS: Method development, validation and application.

An analytical method was developed and validated for the simultaneous determination of alpha, beta and gamma-hydroxybutyric acids (AHB, BHB and GHB, respectively) in human hair. Hair samples (10 mg) were pulverized and submitted to extraction using methanol (1 mL) for 10 min. The extract was centrifuged, filtered, and evaporated to dryness at 40 °C under a gentle N flow, dissolved in ethyl acetate (0.

Particle-size distribution (PSD) of pulverized hair: A quantitative approach of milling efficiency and its correlation with drug extraction efficiency.

Different types of hair were submitted to different milling procedures and their resulting powders were analyzed by scanning electron microscopy (SEM) and laser diffraction (LD). SEM results were qualitative whereas LD results were quantitative and accurately characterized the hair powders through their particle size distribution (PSD). Different types of hair were submitted to an optimized milling conditions and their PSD was quite similar.