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Predictive methods have been employed to characterize chemical separation mediums including solvents and absorbents. These studies included creating Abraham solvation parameter models for room-temperature ionic liquids (RTILs) utilizing novel ion-specific and group contribution methodologies, polydimethyl siloxane (PDMS) utilizing standard methodology, and the micelles cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfate (SDS) utilizing a combined experimental setup methodology with indicator variables. These predictive models allows for the characterization of both standard and new chemicals for use in chemical separations including gas chromatography (GC), solid phase microextraction (SPME), and micellar electrokinetic chromatography (MEKC). Gas-to-RTIL and water-to-RTIL predictive models were created with a standard deviation of 0.112 and 0.139 log units, respectively, for the ion-specific model and with a standard deviation of 0.155 and 0.177 log units, respectively, for the group contribution fragment method. Enthalpy of solvation for solutes dissolved into ionic liquids predictive models were created with ion-specific coefficients to within standard deviations of 1.7 kJ/mol. These models allow for the characterization of studied ionic liquids as well as prediction of solute-solvent properties of previously unstudied ionic liquids. Predictive models were created for the logarithm of solute's gas-to-fiber sorption and water-to-fiber sorption coefficient for polydimethyl siloxane for wet and dry conditions. These models were created to standard deviations of 0.198 and 0.122 logunits for gas-to-PDMS wet and dry, respectively, as well as 0.164 and 0.134 log units for water-to-PDMS wet and dry, respectively. These models are particularly useful in solid phase microextraction separations. Micelles were studied to create predictive models of the measured micelle-water partition coefficient as well as models of measured MEKC chromatographic retention factors for CTAB and SDS. The resultant predictive models were created with standard deviations of 0.190 log units for the logarithm of the mole fraction concentration of water-to-CTAB, 0.171 log units for the combined logarithms of both the mole fraction concentration of water-to-CTAB and measured MEKC chromatographic retention factors for CTAB, and 0.153 log units for the combined logarithms of both the mole fraction concentration of water-to-SDS and measured MEKC chromatographic retention factors for SDS.

ABSTRACT The belief that herbal remedies are less invasive on the human body than conventional medicine and the return of the consumer to a more natural lifestyle, has led to the development of a multitude of remedies, with many different uses. Because the use of these herbal remedies has increased drastically in the last decade, it is essential that the quality and efficacy of these products are well regulated. One of the objectives in this study includes the investigation of the presence of marker metabolites in five herbal remedies, namely Serenoa repens, Silybum marianum, Hypericum perforatum, Echinacea purpurea and Gingko biloba. Although most of the brands tested contained the active ingredients assayed for, a few exceptions were found. However, because this study used only thin layer chromatography for analysis of products, verification of these results should be obtained using other more modern methods for example high pressure liquid chromatography. Four brands of Serenoa repens were selected and assayed for the presence of -sitosterol. All four brands tested indicated the presence of -sitosterol. Five brands of Hypericum perforatum were selected and assayed for the presence of hypericin, rutin and chlorogenic acid. Four of the five products tested indicated the presence of hypericin, while three of five products indicated the presence of rutin and chlorogenic acid. Five brands of Echinacea purpurea were selected and assayed for the presence of -sitosterol, chlorogenic and caffeic acid. Three of the five products indicated the presence of -sitosterol, while only one of the five products contained chlorogenic acid. Caffeic acid was present in 3 of the 5 products. Seven brands of Gingko biloba were selected and assayed for the presence of rutin and bilobalide. Five of the seven products indicated the presence of rutin and bilobalide. Four brands of Silybum marianum were selected and assayed for the presence of both taxifolin and sylibin. Only two of the four products contained both taxifolin and silybin. The second objective of this study is to provide a literature review of the five herbal remedies mentioned above. Amongst the topics discussed were uses of these plants, evidence from studies conducted, chemistry and mechanism of action of the active molecules contained in the plants.

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Kratom is an herbal substance that produces opioid-like and stimulant-like effects. Kratom contains bioactive alkaloids that include mitragynine and 7-OH mitragynine. Both substances activate mu-opioid receptors as well as bind to adrenergic, dopaminergic, and serotonergic receptors, which may be responsible for the stimulant effects. There is no current approved use of kratom or kratom products by the USFDA, but it is currently being used by individuals for management of drug withdrawal, pain, fatigue, and mental health problems. Multiple serious but rare side-effects have been reported, including gastrointestinal, respiratory, psychiatric, cardiovascular issues. Thus, the USDEA considers it to be a Drug and Chemical of Concern and has warned the public against risks of Kratom use. As such, research on Kratom products is necessary to better understand risks and inform policy regarding regulation. Here, we sought to develop a method by which the pharmacologically active mitragynine and its active metabolite 7-OH mitragynine could be measured in various kratom products. The quantification of each utilized high pressure liquid chromatography with ultra-violet detection (HPLC-UV). An XBridge C18 column with 3.5 um particle size, 4.6 x 150 mm was used, and separation was achieved using a gradient elution with acetonitrile and 0.1% formic acid. The flow rate was 1 mL/min, and the oven temperature was set at 40oC. UV detection was at 254 nm. The 7-OH mitragynine peak was visible at 2.5 minutes and the mitragynine at 3.55 minutes. In conclusion, this method has potential to provide utility for detection and quantification of pharmacologically active compounds in kratom products.

A high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection was developed and validated for the quantification of lorazepam in oral solution. The chromatographic conditions include an isocratic separation (25% water / 75% methanol at a flow rate of 0.500 ml/min) on a Waters X=Bridge C18 column (150 x 4.6 mm; 3.5-micron particle size). The method was validated using guidance from the United States Pharmacopeia (USP) chapter, including investigation of system suitability, precision, accuracy, linearity, and specificity. The calibration curves on three non-consecutive days met the linearity criteria R2 >0.99. Each chromatogram for 200 mcg/mL calibration samples, designated as 100% assay level, met system suitability criteria of resolution ≥2.0, tailing factor ≤2.0, column efficiency (theoretical plates) ≥2000, and precision of prior metrics % RSD ≤1.0. Three replicates of each concentration, 150 mcg/mL at 75% assay, 200 mcg/mL at 100% assay, and 250 mcg/mL at 125% assay were assessed for precision and accuracy over 3 days. Precision and accuracy were evaluated and met the inter-day (repeatability) criteria % RSD and % Error ≤ 2% and intra-day (intermediate) criteria % RSD and % Error ≤ 5% at the 75%, 100%, and 125% assay levels. To assess for specificity, 200 mcg/mL samples were assessed for degradation after being subjected to heat (>60°C), oxidation (3% H2O2), acidic (0.1M HCl), and basic (0.1M NaOH) environments. Samples from each condition were evaluated for lorazepam recovery at 0, 24, and 48 hours. Most drug loss was observed with the samples subjected to acidic and oxidative environments, with 14.71% and 13.16% drug loss, respectively after 48 hours. This method was developed to support the 30-day stability investigation of lorazepam oral solution when stored in oral syringes at room and refrigerated temperatures.

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