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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The discriminatory ability of analytical quality control test methods : a comparison of test results from different international monographs of quinine sulfate tablets / Chantal Britz

Britz, Chantal January 2013 (has links)
Malaria is a parasitic disease claiming one million lives worldwide annually. Unfortunately, malaria-endemic countries in need of good quality medicines are also overwhelmed with counterfeit or substandard medicine. This results in treatment inefficacy, resistance towards treatment and death. Counterfeit or substandard quinine sulfate tablets are known to have infiltrated the market, however at this point in time, treatment efficacy of quinine sulfate has fortunately not yet been significantly impaired by resistance, but immediate action is required to prevent it from becoming obsolete. Validated analytical methods with justified specifications are effective in controlling the quality of medicines and to minimise the effect of poor quality medicines. Pharmacopoeia specifies analytical quality control procedures and accompanying specifications to standardise acceptable levels of product quality. Understandably, different monographs of different pharmacopoeias are developed by different independent laboratories and therefore their respective test procedures/specifications for the same FPP may differ from each other. Institutions such as the Pharmacopoeial Dicussion Group (PDG) aim to harmonise pharmacopoeia in order to synchronise final outcomes. This study evaluated the relevancy of differences in analytical procedures, results and specifications for quinine sulfate tablets set by the United States Pharmacopoeia (USP), British Pharmacopoeia (BP) and International Pharmacopoeia (Ph.Int.) in an aim to ensure that these different methods all provide with similar final outcomes and that they be effective in successfully evaluating the quality of quinine sulfate tablets. Four quinine sulfate tablet products were obtained from different manufacturers and were subjected to the tests of all three pharmacopoeia – BP, USP and Ph.Int. The results from identification, assay and related substance testing concluded that the outcomes were the same between the pharmacopoeia despite their differences in techniques/procedures/specifications. The assay, identification and related substances methods and specifications set by each respective monograph were deemed appropriate to evaluate the quality of quinine sulfate tablets. Even with differences in methodology, quantitative techniques and specifications, the USP and BP dissolution methods for quinine sulfate tablets shared the same final outcome at the first stage of dissolution, whereas none of the products achieved a compliant outcome using the Ph.Int. dissolution method. Possible reasons for the poor dissolution (when using the Ph.Int. method) were identified and investigated. Investigation into the solubility of quinine sulfate found the Ph.Int. dissolution method conditions to be too stringent, as the solubility of quinine sulfate in phosphate buffer pH 6.8 (dissolution medium specified by the Ph.Int.) was found to be much less than in acidic media (as proposed by the BP and USP dissolution methods). Several adapted dissolution methods (called developmental studies) were investigated to serve as potential alternatives for the Ph.Int. dissolution method. The developmental studies investigated an alternative dissolution medium, agitation rates (50 rpm, 75 rpm, 100 rpm) and medium volumes (500 ml, 750 ml, 900 ml and 1000 ml). Developmental study 6 was proposed as an alternative dissolution method. Developmental study 6 stipulates the use of the same medium as the original Ph.Int. method, as it was deemed the medium of choice for its discriminatory ability. To address the impaired solubility of quinine sulfate in phosphate buffer, the medium volume and agitation were increased (in reference to the original method) to 900 ml and 100 rpm respectively. The same analytical quantitation technique (UV-Vis spectroscopy) is proposed for Developmental study 6. The newly proposed method provided with final outcomes comparable to that of the USP and BP, however having more discriminatory power than the USP and BP. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2014
2

The discriminatory ability of analytical quality control test methods : a comparison of test results from different international monographs of quinine sulfate tablets / Chantal Britz

Britz, Chantal January 2013 (has links)
Malaria is a parasitic disease claiming one million lives worldwide annually. Unfortunately, malaria-endemic countries in need of good quality medicines are also overwhelmed with counterfeit or substandard medicine. This results in treatment inefficacy, resistance towards treatment and death. Counterfeit or substandard quinine sulfate tablets are known to have infiltrated the market, however at this point in time, treatment efficacy of quinine sulfate has fortunately not yet been significantly impaired by resistance, but immediate action is required to prevent it from becoming obsolete. Validated analytical methods with justified specifications are effective in controlling the quality of medicines and to minimise the effect of poor quality medicines. Pharmacopoeia specifies analytical quality control procedures and accompanying specifications to standardise acceptable levels of product quality. Understandably, different monographs of different pharmacopoeias are developed by different independent laboratories and therefore their respective test procedures/specifications for the same FPP may differ from each other. Institutions such as the Pharmacopoeial Dicussion Group (PDG) aim to harmonise pharmacopoeia in order to synchronise final outcomes. This study evaluated the relevancy of differences in analytical procedures, results and specifications for quinine sulfate tablets set by the United States Pharmacopoeia (USP), British Pharmacopoeia (BP) and International Pharmacopoeia (Ph.Int.) in an aim to ensure that these different methods all provide with similar final outcomes and that they be effective in successfully evaluating the quality of quinine sulfate tablets. Four quinine sulfate tablet products were obtained from different manufacturers and were subjected to the tests of all three pharmacopoeia – BP, USP and Ph.Int. The results from identification, assay and related substance testing concluded that the outcomes were the same between the pharmacopoeia despite their differences in techniques/procedures/specifications. The assay, identification and related substances methods and specifications set by each respective monograph were deemed appropriate to evaluate the quality of quinine sulfate tablets. Even with differences in methodology, quantitative techniques and specifications, the USP and BP dissolution methods for quinine sulfate tablets shared the same final outcome at the first stage of dissolution, whereas none of the products achieved a compliant outcome using the Ph.Int. dissolution method. Possible reasons for the poor dissolution (when using the Ph.Int. method) were identified and investigated. Investigation into the solubility of quinine sulfate found the Ph.Int. dissolution method conditions to be too stringent, as the solubility of quinine sulfate in phosphate buffer pH 6.8 (dissolution medium specified by the Ph.Int.) was found to be much less than in acidic media (as proposed by the BP and USP dissolution methods). Several adapted dissolution methods (called developmental studies) were investigated to serve as potential alternatives for the Ph.Int. dissolution method. The developmental studies investigated an alternative dissolution medium, agitation rates (50 rpm, 75 rpm, 100 rpm) and medium volumes (500 ml, 750 ml, 900 ml and 1000 ml). Developmental study 6 was proposed as an alternative dissolution method. Developmental study 6 stipulates the use of the same medium as the original Ph.Int. method, as it was deemed the medium of choice for its discriminatory ability. To address the impaired solubility of quinine sulfate in phosphate buffer, the medium volume and agitation were increased (in reference to the original method) to 900 ml and 100 rpm respectively. The same analytical quantitation technique (UV-Vis spectroscopy) is proposed for Developmental study 6. The newly proposed method provided with final outcomes comparable to that of the USP and BP, however having more discriminatory power than the USP and BP. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2014
3

Evaluating the effectiveness of Benford's law as an investigative tool for forensic accountants / Lizan Kellerman

Kellerman, Lizan January 2014 (has links)
“Some numbers really are more popular than others.” Mark J. Nigrini (1998a:15) The above idea appears to defy common sense. In a random sequence of numbers drawn from a company’s financial books, every digit from 1 to 9 seems to have a one-in-nine chance of being the leading digit when used in a series of numbers. But, according to a mathematical formula of over 60 years old making its way into the field of accounting, certain numbers are actually more popular than others (Nigrini, 1998a:15). Accounting numbers usually follow a mathematical law, named Benford’s Law, of which the result is so unpredictable that fraudsters and manipulators, as a rule, do not succeed in observing the Law. With this knowledge, the forensic accountant is empowered to detect irregularities, anomalies, errors or fraud that may be present in a financial data set. The main objective of this study was to evaluate the effectiveness of Benford’s Law as a tool for forensic accountants. The empirical research used data from Company X to test the hypothesis that, in the context of financial fraud investigations, a significant difference between the actual and expected frequencies of Benford’s Law could be an indication of an error, fraud or irregularity. The effectiveness of Benford’s Law was evaluated according to findings from the literature review and empirical study. The results indicated that a Benford’s Law analysis was efficient in identifying the target groups in the data set that needed further investigation as their numbers did not match Benford’s Law. / MCom (Forensic Accountancy), North-West University, Potchefstroom Campus, 2014
4

Evaluating the effectiveness of Benford's law as an investigative tool for forensic accountants / Lizan Kellerman

Kellerman, Lizan January 2014 (has links)
“Some numbers really are more popular than others.” Mark J. Nigrini (1998a:15) The above idea appears to defy common sense. In a random sequence of numbers drawn from a company’s financial books, every digit from 1 to 9 seems to have a one-in-nine chance of being the leading digit when used in a series of numbers. But, according to a mathematical formula of over 60 years old making its way into the field of accounting, certain numbers are actually more popular than others (Nigrini, 1998a:15). Accounting numbers usually follow a mathematical law, named Benford’s Law, of which the result is so unpredictable that fraudsters and manipulators, as a rule, do not succeed in observing the Law. With this knowledge, the forensic accountant is empowered to detect irregularities, anomalies, errors or fraud that may be present in a financial data set. The main objective of this study was to evaluate the effectiveness of Benford’s Law as a tool for forensic accountants. The empirical research used data from Company X to test the hypothesis that, in the context of financial fraud investigations, a significant difference between the actual and expected frequencies of Benford’s Law could be an indication of an error, fraud or irregularity. The effectiveness of Benford’s Law was evaluated according to findings from the literature review and empirical study. The results indicated that a Benford’s Law analysis was efficient in identifying the target groups in the data set that needed further investigation as their numbers did not match Benford’s Law. / MCom (Forensic Accountancy), North-West University, Potchefstroom Campus, 2014

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