In this paper we report the possibility of using the X-ray powder diffraction (XRPD) technique to detect the gamma-hydroxybutyric acid (GHB) as its sodium salt in different beverages but because it is not possible to freely buy them, beta-hydroxybutyric acid (BHB) and its sodium salt (NaBHB) were used as a model to fine tune an X-ray diffraction method for the qualitative analysis of the sodium salt of GHB. The method requires a small quantity of beverage, and an easy sample preparation, that consists only in the NaOH addition to the drink and a subsequent drying step. The dry residue obtained can be easily analyzed with XRPD using a single crystal X-ray diffractometer to exploit its high sensitivity that allows very fast patterns collection. Several beverages with different NaBHB:NaOH molar ratios were tested and the results show that NaBHB is detected in all drinks analyzed when NaBHB:NaOH molar ratio is 1:50 using characteristic peak at very low 2θ values that permits to detect its presence also in complex beverage matrices. Moreover, depending on the NaOH amount added, shifting and/or splitting of the characteristic peak of the NaBHB salt was observed, and the origin of this behavior was investigated.

1) Background: Recently, illegal abuse of γ-hydroxybutyric acid (GHB) has increased in drug-facilitated crimes, but determination of GHB exposure and intoxication is difficult due to rapid metabolism of GHB. Its biochemical mechanism has not been completely investigated. And metabolomic study by polyamine profile and pattern analyses was not performed in rat urinefollowing intraperitoneal injection with GHB. 2) Methods: Polyamine profiling analysis by gas chromatography-mass spectrometry combined with star pattern recognition analysis was performed in this study. Multivariate statistical analysis was used to evaluate discrimination between control and GHB administration groups. 3) Results: Six polyamines were determined in control, single and multiple GHB administration groups. Star pattern showed distorted hexagonal shapes with characteristic and readily distinguishable patterns for each group. N¹-Acetylspermine (p < 0.001), putrescine (p <0.006), N¹-acetylspermidine (p <0.009), and spermine (p < 0.027) were significantly increased in single administration group but were significantly lower in the multiple administration group than in the control group. N¹-Acetylspermine was the main polyamine for discrimination between control, single and multiple administration groups. Spermine showed similar levels in single and multiple administration groups. 4) Conclusions: The polyamine metabolic pattern was monitored in GHB administration groups. N¹-Acetylspermine and spermine were evaluated as potential biomarkers of GHB exposure and addiction.

We reported previously that poly (3-hydroxybutyrate) (PHB) oligomer is an effective antimicrobial agent against gram-positive bacteria, gram-negative bacteria, fungi and multi-drug resistant bacteria. In this work, it was further found that polyethylene glycol (PEG) can promote the antimicrobial effect of PHB oligomer synergistically. Three hypothetic mechanisms were proposed, that is, generation of new antimicrobial components, degradation of PHB macromolecules and dissolution/dispersion of PHB oligomer by PEG. With a series of systematic experiments and characterizations of HPLC-MS, it was deducted that dissolution/dispersion of PHB oligomer dominated the synergistic antimicrobial effect between PHB oligomer and PEG. This work demonstrates a way for promoting antimicrobial effect of PHB oligomer and other antimicrobial agents through improving hydrophilicity.