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The drug lorazepam is a benzodiazepine by class and is used in many healthcare settings as a sedative and anxiolytic. This drug is often found in hospital settings in the dosage form of an oral concentrate, of which patients may receive doses of 0.5 - 1 milliliters. A typical supply of drug product would come in a 30-milliliter bottle requiring protection from light, constant refrigeration, and a beyond use date of 90-days once the bottle is opened, according to package instructions. Aliquoting lorazepam oral solution into syringes allows for higher efficiency facilitated dispensing than as-needed dispensing from a multi-use stock bottle. Preparing individual doses in oral syringes before they are needed may also reduce dosing errors. There is currently no data that supports the practice of storing lorazepam oral solution in syringes, which introduces uncertainty of the product’s safety and efficacy over time. In this study, 2mg/mL lorazepam oral solution was aliquoted into syringes in 1mL doses from 2 multi-dose stock bottles and randomly allocated in an even proportion to be stored in either a room temperature or refrigerated environment. A validated stability-indicating high-performance liquid chromatography method with ultraviolet detection was used to investigate the concentration of lorazepam in the syringe-stored solutions. A fresh calibration curve in the range of 50 – 250 micrograms/mL lorazepam was prepared each day to facilitate quantification. Baseline lorazepam concentrations were measured on the day the study was initiated and designated as 100% recovery samples. Subsequent samples were analyzed from the refrigerated and room temperature syringes in triplicate at time points of 24, 48, and 96 hours and 7, 10, 14, 21, and 28 days. Our data predict that lorazepam can be safely stored in oral syringes at room and refrigerated temperatures for greater than 7 days.

<p> A new technique for the systematic identification of metal-protein complexes combining gel chromatography with either neutron activation analysis or radioactive tracer methods has been proposed. The technique has been tested on the copper in serum situation to evaluate the results obtained on a well-known system.</p> <p> It was then applied to manganese in serum, manganese in erythrocytes and copper in erythrocytes. The results indicate that serum contains two manganese-binding proteins, one of low molecular weight and relatively labile in nature, the other of higher molecular weight and incorporating radioactive manganese in vivo at some definite time interval subsequent to the isotope's administration.</p> <p> Manganese in erythrocytes occurs as a porphyrin bound to apoglobin as a manganese analogue of hemoglobin.</p> <p> Copper in erythrocytes appears to exist in two forms - one firmly bound to erythrocuprein, the other more loosely bound to the same protein.</p> / Thesis / Doctor of Philosophy (PhD)

<p> An inexpensive method was developed for the conversion of a high performance liquid chromatography (HPLC) system for use with 1 mm I.D. microbore columns. Chromatographic performance of the system was tested under both isocratic and gradient elution conditions, using a standard mixture of 16 polycyclic aromatic hydrocarbons (PAH).</p> <p> The microbore column HPLC was also coupled to a mass spectrometer equipped with a moving belt interface. Chromatographic performance under isocratic and gradient elution and mass spectral performance under scanning and selected ion monitoring modes were tested using the PAH standard.</p> <p> A marine sediment extract was subjected to qualitative and quantitative analysis for PAH. Qualitative results on the sample were obtained from a combination of retention indices, mass spectra, and retention times. Quantitation was performed by microbore column liquid chromatography-mass spectrometry (LC/MS) in the selected ion monitoring mode of operation. The method of calibration used was external calibration.</p> <p> The microbore column HPLC system exhibited good chromatographic behavior. Resolution, peak shape and short term retention time reproducibility were good, although, long term retention time fluctuations, due to changing mobile phase flow rates, were noted.</p> <p> The combination of microbore column HPLC with a moving belt interface and mass spectrometer gave excellent results. Problems commonly encountered with conventional column (4.6 mm I.D.) LC/MS, such as backstreaming, droplet formation, and splattering were greatly reduced, resulting in no apparent loss of chromatographic integrity and stable mass spectrometer operating conditions. These operating conditions proved to be most advantageous in the quantitative analysis of the marine sediment extract by selected ion monitoring.</p> / Thesis / Master of Science (MSc)

Various innovative separation methods in chromatography have been proposed. The interaction of the 4-t-butylphenyl group with b-cyclodextrin is well-known; compounds tagged with the 4-t-butylphenyl group are separated from untagged compounds using b-cyclodextrin column. In this study, increasing the chain length of tagged molecules does not increase the retention time but depends on other functional groups present, while increasing the number of tags in a molecule increases retention time. The t-butyl group was also compared to adamantyl and lithocholic acid tags. In-house b-cyclodextrin columns were synthesized to observe the effect of the linkage of the cyclodextrin molecule to the support. Furthermore, tagged products could be separated from the starting materials using in-house columns employing flash b-cyclodextrin. Supported room temperature ionic liquids (SILs/MSILs) were explored for the extraction of polyunsaturated triacylglycerols (PUTAGs).Various room temperature ionic liquids (RTILs) with silver salts were tested for extraction effectiveness.The most hydrophobic RTIL [Hmim][PF6] in this study, with dissolved AgBF4 proved to be the best combination for effective extraction. RTILs supported on silica gel and mesoporous SBA-15 reacted with silver salts (psorbents) were synthesized and characterized. The later support revealed a conserved mesopore structure by SEM, TEM, SAXS and N2 isotherms. Trilinolenin (tri-18:3) quantification was explored by conversion to polyunsaturated fatty acid alcohols and methyl esters, Proton NMR spectroscopy and by non-aqueous reverse phase (NARP)-HPLC with evaporative light scattering detector (ELSD). Tri-18:3 and its free fatty acid (FFA-18:3) were extracted selectively and quantified using a two-step methodology. The extraction of a-tocopherol with RTILS modified with organic anions was also successfully demonstrated. Finally, studies of chiral stationary phases with on-resin cyclic oligoprolines were demonstrated. Cross linking of linear oligoprolines was shown to disrupt the poly-proline helix (II) thus leading to lower number of analytes resolved. On-resin cyclic oligoproline synthesis was successful for penta- and tetraproline but failed for the triproline. PyBOP/HOBt/DIPEA was employed for effective cyclization. The on-resin cyclic oligoproline CSP showed a lower number of resolved analytes, implying the importance of the poly-proline helix for chiral selectivity. The innovative separations in this study serve as starting points for developing mature separation methods.

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