Thesis (Ph.D.)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Chemistry. Title from title-page of electronic thesis. Bibliography: leaves 144-153.

The development of the monograph of a commonly used Chinese medicine, Lini Semen, for the Hong Kong Chinese Materia Medica Standards (HKCMMS) was recorded. HKCMMS is a set of reliable and internationally recognized standards of Chinese medicine. The monograph of Lini Semen was proposed, endorsed, and under editorial phase for the publication of the 9th volume of HKCMMS. In the proposed HKCMMS monograph of Lini Semen, besides regular content such as macroscopic and microscopic identification, and TLC identification, a HPLC fingerprint method and two assay methods were developed. All methods were well-established and validated. TLC identification: Lini Semen n-hexane extract is identified on a HPTLC Silica gel RP-18 plate, with α-linolenic acid and linoleic acid as the markers. The developing system consisted of acetone, acetic acid and dichloromethane in the ratio of 5:4:2. The spraying reagent was 5% sulphuric acid - ethanol solution and the plate was observed under 366 nm. HPLC fingerprint: Fingerprint of Lini Semen was conducted on a HPLC system with a C8 column. Mobile phase consisted of (A) water and (B) acetonitrile and isopropanol (9:1). Six characteristic peaks, including α-linolenic acid and linoleic acid were detected under 210 nm. Assay: α-Linolenic acid and linoleic acid were detected from Lini Semen n-hexane extract under the same HPLC condition of the fingerprint of Lini Semen. The proposed total content of α-linolenic acid and linoleic acid was not less than 0.56%. Secoisolariciresinol diglucoside (SDG) was detected from hydrolysed Lini Semen extract by HPLC system with a C18 column. Mobile phase consisted of (A) water and (B) acetonitrile. The detection wavelength was 280 nm. The proposed content of SDG was not less than 0.81%. Conclusion: It is the first time to propose a HPLC fingerprint and introduce SDG as a assay marker of Lini Semen in a regional standard monograph. The established methods for TLC identification, HPLC fingerprint, assay of the total content of α-linolenic acid and linoleic acid, as well as assay for SDG were validated with in-house and inter-laboratory comparison to prove that the methods are reliable.

Erythromycin is a macrolide antibiotic used mainly in the treatment of infections caused by gram-positive organisms. Erythromycin base is rap idly degraded in acidic media necessitating the use of structurally modified erythromycin derivatives or acid resistant dosage forms in order to decrease gastric inactivation of the drug. The majority of pharmacokinetic studies to-date have utilized relatively non-specific microbiological assay procedures which are unable to differentiate between concentrations of active erythromycin base and the inactive pro-drug derivatives. A high-performance liquid chromatographic (HPLC) technique is described for the simultaneous determination of erythromycin base and propionate (inactive pro-drug form) in human serum and urine following the oral administration of erythromycin estolate, an acid stable derivative of erythromycin. The method involves a solid-phase extraction step prior to chromatography on a C18 reversed-phase column with coulometric electrochemical detection. Sample handling and storage techniques are presented which minimize hydrolysis of the inactive ester moiety between sample collection and analysis, thereby more accurately reflecting the in vivo situation than in previously published studies. Results from single dose pharmacokinetic studies indicate that only 10-15% of the total erythromycin concentration in vivo is present as the active base component following oral administration of erythromycin estolate. This percentage increases to approximately 25% during multiple dose administration. Novel urinary excretion data are presented which reveal that approximately 40% and 55% of the total erythromycin excreted in urine is excreted as erythromycin base following single and multiple dosages respectively. Computer fitting of mean serum concentration-time data revealed that an open one compartment model with linear first order absorption and elimination best described the absorption and disposition of erythromycin, although poor computer fits for individual data sets were observed. Some evidence of non-linear elimination is presented utilizing both compartmental and non-compartmental pharmacokinetic techniques. Large intra-and inter-personal variability in erythromycin absorption and disposition was experienced which was evaluated in five subjects who each received one 500 mg erythromycin estolate tablet from the same batch, on three separate occasions. In addition. an HPLC method is described for the analysis of "total erythromycin" concentrations following erythromycin estolate administration which involves hydrolysis of the ester component prior to chromatography. as well as an HPLC method utilizing amperometric electrochemical detection capable of monitoring the stability of erythromycin base in stored biological fluids. These methods were uti I ized in various stability studies involving erythromycin base and propionate as well as for the analysis of erythromycin estolate dosage forms.

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by Tsoi Yeung-pang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 105-106). / Chapter I. --- Acknowledgements --- p.i / Chapter II. --- Abstract --- p.ii / Chapter III. --- Table of contents --- p.iv / Chapter IV. --- List of Tables and Figures --- p.v / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Modes of chromatography / Chapter 1.2 --- Objective of the present study / References / Chapter Chapter 2. --- Instrumentation and theory --- p.8 / Chapter 2.1 --- Instrumentation of HPLC / Chapter 2.2 --- Theory of liquid chromatography / References / Chapter Chapter 3. --- Determination of citrate in pharmaceutical preparations by HPLC using indirect photometric detection --- p.21 / Chapter 3.1 --- Introduction / Chapter 3.2 --- Review of the analytical methods / Chapter 3.3 --- Theory of detection / Chapter 3.4 --- Experimental / Chapter 3.5 --- Results and discussion / Chapter 3.6 --- Conclusion / References / Chapter Chapter 4. --- Determination of camphor and menthol by HPLC using indirect conductometric detection --- p.74 / Chapter 4.1 --- Introduction / Chapter 4.2 --- Review of the analytical methods / Chapter 4.3 --- Theory of detection / Chapter 4.4 --- Experimental / Chapter 4.5 --- Results and discussion / Chapter 4.6 --- Conclusion / References

Siu Yuen Yu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 122-139). / Abstracts in English and Chinese. / Abstract (English) --- p.i / Abstract (Chinese) --- p.iii / Acknowledgments --- p.v / Table of Contents --- p.vi / List of Figures --- p.x / List of Tables --- p.xvi / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter CHAPTER 2 --- LITERATURE REVIEW --- p.7 / Chapter 2.1 --- Traditional methods for studying zooplankton feeding selectivity --- p.7 / Chapter 2.1.1 --- Cell counting after laboratory feeding experiments --- p.7 / Chapter 2.1.2 --- Direct examination of gut contents --- p.8 / Chapter 2.1.3 --- Use of radioactive tracers --- p.9 / Chapter 2.1.4 --- Gut fluorescence method --- p.9 / Chapter 2.2 --- High Performance Liquid Chromatography analysis of phytoplankton pigments --- p.11 / Chapter 2.2.1 --- Principle --- p.11 / Chapter 2.2.2 --- Pigments as signature markers of phytoplankton --- p.11 / Chapter 2.2.3 --- Development of HPLC analysis of phytoplankton pigments --- p.16 / Chapter 2.2.4 --- Advantages of HPLC analysis of phytoplankton pigments --- p.17 / Chapter 2.2.5 --- Limitation of HPLC analysis of phytoplankton pigments --- p.18 / Chapter 2.3 --- Zooplankton feeding selectivity --- p.19 / Chapter 2.3.1 --- Ecological importance of zooplankton feeding selectivity --- p.19 / Chapter 2.3.2 --- Factors affecting zooplankton feeding selectivity --- p.19 / Chapter 2.3.3 --- Feeding selectivity of zooplankton studied in this study --- p.21 / Chapter 2.3.3.1 --- p. avirostirs --- p.21 / Chapter 2.3.3.2 --- Paracalanus spp --- p.22 / Chapter 2.3.3.3 --- Pseudevadne tergestina --- p.23 / Chapter 2.4 --- Pigment degradation in guts of zooplankton --- p.24 / Chapter 2.4.1 --- Experimental design --- p.24 / Chapter 2.4.2 --- Pigment degradation --- p.24 / Chapter 2.5 --- "Tolo Harbour, Hong Kong" --- p.26 / Chapter 2.5.1 --- Site description --- p.26 / Chapter 2.5.2 --- Phytoplankton and zooplankton in Tolo Harbour --- p.27 / Chapter CHAPTER 3 --- MATERIALS AND METHODS --- p.28 / Chapter 3.1 --- Field sampling --- p.28 / Chapter 3.1.1 --- Study of seasonal patterns in zooplankton feeding selectivity --- p.28 / Chapter 3.1.1.1 --- Collection of phytoplankton and zooplankton for pigment analysis --- p.28 / Chapter 3.1.1.2 --- Collection of phytoplankton and zooplankton for plankton enumeration --- p.30 / Chapter 3.1.2 --- Collection of phytoplankton and zooplankton for laboratory feeding experiments --- p.32 / Chapter 3.2 --- Laboratory experiments and data analysis --- p.33 / Chapter 3.2.1 --- Study of seasonal patterns in zooplankton feeding selectivity --- p.33 / Chapter 3.2.1.1 --- HPLC of phytoplankton pigments --- p.33 / Chapter 3.2.1.2 --- Fluorometric measurement of chlorophyll-α --- p.35 / Chapter 3.2.1.3 --- Plankton identification and enumeration --- p.36 / Chapter 3.2.2 --- Laboratory feeding experiments for investigation of pigment degradation in zooplankton gut --- p.37 / Chapter CHAPTER 4 --- RESULTS --- p.41 / Chapter 4.1 --- Information on Tolo Harbour --- p.41 / Chapter 4.1.1 --- Temperature and salinity in Tolo Harbour --- p.41 / Chapter 4.1.2 --- Plankton composition and community in Tolo Harbour --- p.43 / Chapter 4.1.2.1 --- Phytoplankton --- p.43 / Chapter 4.1.2.2 --- Zooplankton --- p.50 / Chapter 4.2 --- Seasonal zooplankton feeding selectivity investigated by HPLC phytoplankton pigment analysis --- p.53 / Chapter 4.2.1 --- Verification of HPLC pigment analysis by fluorometric analysis --- p.53 / Chapter 4.2.2 --- Correlations between phytoplankton cell densities and pigment concentrations in water samples --- p.55 / Chapter 4.2.3 --- Feeding selectivity of zooplankton on different phytoplankton groups --- p.73 / Chapter 4.2.4 --- Feeding selectivity of zooplankton on dinoflagellates --- p.87 / Chapter 4.2.5 --- Feeding selectivity of zooplankton on diatoms --- p.87 / Chapter 4.3 --- Feeding selectivity on phytoplankton by other cladoceran - Pseudevadne tergestina --- p.89 / Chapter 4.4 --- Pigment degradation in zooplankton guts after ingestion of phytoplankton --- p.90 / Chapter 4.5 --- Clearance rates of P. avirostris and Paracalanus spp. in feeding experiments --- p.101 / Chapter CHAPTER 5 --- DISCUSSIONS --- p.105 / Chapter 5.1 --- Experiment design --- p.105 / Chapter 5.2 --- Seasonal zooplankton feeding selectivity investigated by HPLC phytoplankton pigment analysis --- p.108 / Chapter 5.2.1 --- Correlations between phytoplankton cell densities and pigment concentrations in water samples --- p.108 / Chapter 5.2.2 --- Feeding selectivity of zooplankton on different phytoplankton groups --- p.108 / Chapter 5.2.3 --- Feeding selectivity of Pseudevadne tergestina --- p.111 / Chapter 5.3 --- Feeding experiments for investigating pigment degradation in guts of zooplankton --- p.112 / Chapter 5.3.1 --- Principle --- p.112 / Chapter 5.3.2 --- Degradation for different pigments in guts of P. avirostris and Paracalanus spp. --- p.112 / Chapter 5.4 --- Clearance rates of P. avirostris and Paracalanus spp. --- p.114 / Chapter 5.4.1 --- p. avirostris --- p.114 / Chapter 5.4.2 --- Paracalanus spp. --- p.115 / Chapter 5.5 --- Limitations of HPLC analysis of phytoplankton pigments --- p.116 / Chapter 5.6 --- Environmental events related to feeding selectivity of zooplankton in Tolo Harbour --- p.118 / Chapter 5.6.1 --- Energy transfer in trophic level --- p.118 / Chapter 5.6.2 --- Abilities of p. avirostris and Paracalanus spp. to control red tides in Tolo Harbour --- p.118 / Chapter CHAPTER 6 --- CONCLUSION --- p.120 / REFERENCES --- p.122 / APPENDIX