Magister Pharmaceuticae - MPharm / This study was based on Dioxy MP 14 (DMP), a brand of stabilized chlorine dioxide (SCD). The active pharmaceutical ingredient (API) of DMP is chlorine dioxide (CD) which is a potent oxidant and biocide. These properties have proved invaluable for various applications. The main goals of this study were: to evaluate the effectiveness of DMP for disinfecting Mycobateria tuberculosis (TB) contaminated medical instruments, devices, floors and surfaces; to investigate the stability of DMP; and to explore possibilities for medical application of DMP. Evaluation of disinfectant activity of DMP on TB was performed using the spectrophotometric method, a modification of the European suspension test, EN 14348. M. bovis BCG was employed as surrogate in this test. Results were as follows: The minimum inhibitory concentration (MIC₉₀) = 12.5 ppm; the minimum bactericidal concentration (MBC) = 15.4 ppm; the Mycobactericidal Effect (ME) = 8.8log reduction; and the minimum inhibitory concentration (MIC₉₀) x minimum exposure time (CT) = 12.5 ppm.s. The long term stability study of DMP was performed by monitoring the rate of degradation of DMP stored in the fridge (2-8 °C), in the oven (40 °C), and under ambient conditions (15-30 °C). Analytical methods of assessing DMP concentration was by Iodometric titration method. The shelf life of DMP stored in a transparent bottle at room temperature was 9.8 weeks, as opposed to 52.7 weeks when stored in an amber colored reagent bottle at the same temperature. Both oven samples had an expiry date of about 20 weeks and the fridge samples about 70 weeks. Foam formulations for a vaginal douche (VGD), mouth rinse (MRF), and foot/sit bubble bath (F/SBB)], were developed in the laboratory. DMP and the formulated concentrate were designed to be mixed just prior to administration. During foam evaluation studies, a mechanical overhead stirrer was used to generate foam. Foamability was assessed by quantifying the amount of foam generated. The stability of foams were assessed by: 1) determining the rate of foam decay and the rate of foam drainage observed concurrently from foam loaded in a measuring cylinder; and 2) determining the life span of single bubbles of each foam system i.e. the bubble breaking time (BBT). The density of each foam system was also determined. Potentiometric acid base titration was used to select suitable adjuster alkali, and to show the benefits of employing a buffer. Concentrate development was initiated by a simple mixture of all the ingredients followed by stirring and observing the deviations from desired quality attributes of the product. The subsequent five processes were improvements designed to circumvent the shortcomings of the initial procedure to arrive at the optimized method E. Prototype formulations were employed to optimize excipient quantities to eventually arrive at an optimized master formula. In foam evaluation, it was found that sodium lauryl sulphate/ammonium lauryl sulphate/cocoamidopropyl betaine/cetostearyl alcohol (SLS/ALS/CAPB/CSA) foam system was the most appropriate to use in the formulation. NaOH was selected as the adjuster solution and KHP as the buffer. The dosage formula (DF) of the VGD and F/SBB was determined to be MDF = 5 ml of 50 ppm DMP + 5 ml concentrate + 40 ml water = 50 ml and that of MRF as MDF = 19 ml diluted concentrate + 1 ml of 50 ppm DMP. In conclusion, DMP was found to be a highly effective disinfectant against Mycobacteria. DMP has reasonable shelf life if stored appropriately. Pharmaceutical formulation from DMP was found to be delicate due to the narrow pH window of DMP stability, but is feasible.

No description available.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 115-124).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1951. / Includes bibliographical references (leaves 106-109).

Thesis (Ph. D.)--Institute of Paper Chemistry, 1958. / Bibliography: leaves 43-44.

The oxidation reaction mechanisms of water soluble textile dyes amaranth (an azo dye), brilliant blue-R (a triaryl dye) and safranine-O (an azine dye) with oxidants- hypochlorite and chlorine dioxide, were investigated. The detailed kinetics of the reactions of the three dyes was studied under excess concentrations of the oxidant and other reagents. The depletion of concentration of the chosen dye, taken at low concentration was monitored using a Hi-Tech SF-61 DX2 double mixing micro volume stopped-flow apparatus. The hypochlorite initiated oxidations were investigated as function of varying concentration of oxidant and hydrogen ion, ionic strength and temperature. For the chosen dyes and reaction conditions, the depletion of dye followed pseudo first-order kinetics and the rate constants were estimated using KinetAsystTM software. All the three reactions had first-order dependence on the oxidant concentration, and the reaction rates increased by varied extent with increase in [H+]0. The role of acid in their reaction mechanisms was established. The kinetic data was analysed to evaluate the rate constants for the competitive pathways initiated by hypochlorite ion and hypochlorous acid. The overall second-order rate coefficients for the OCl- and HOCl initiated reactions were estimated for all the three reactions. Major oxidation products for the reactions were separated and characterized by 1H NMR and 13C NMR and GC-MS techniques and the stoichiometry was established. The energy parameters inclusive of Arrhenius factor, enthalpy, entropy and energy of activations for the oxidation of three dyes both by OCl- and HOCl species were estimated. Based on the experimental findings, the probable rate laws, mechanisms and reaction schemes were described. Simulations studies were conducted to validate the proposed mechanisms using SIMKINE2 computer programme. The rate of oxidation of safranine-O is greater than that of amaranth and brilliant blue-R with OCl- / HOCl reaction. Following similar protocol, the oxidations of the chosen dyes with chlorine dioxide were investigated by monitoring the depletion kinetics of dye as function of varying concentration of ClO2 and OH- ion, ionic strength and temperature. All the three dyes, exhibited pseudo first-order kinetics and the rate constants were estimated using KinetAsystTM software. All the three reactions had first-order dependence on the oxidant concentration at pH conditions 7.0, 8.0 and 9.0 suggesting that reaction mechanism remains unaltered with pH variation. The effect of hydroxide ion on the reaction rate revealed that it acts as catalyst. All the three reactions had first-order dependence on [OH-]0, when its concentration was low; but the order with respect to [OH-] decreased as [OH-] increased stoichiometry proportion to reactants. The catalytic constant for hydroxide catalysed reaction was estimated for all the three reactions. Kinetic salt effect experiments were conducted to identify the possible reaction species involved in the reactions. The major reaction products were characterized by 1H NMR, 13C NMR and GC-MS techniques. The stoichiometry ratios were established and energy parameters were estimated. The rate laws and probable reaction mechanisms were proposed and appropriate reaction schemes for all the reactions were described. The elucidated mechanisms were confirmed by simulation studies using SIMKINE2 software. At neutral pH the rate of oxidation of amaranth is greater than safranine-O and brilliant blue-R, and brilliant blue R being the slowest. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2010.

This problem was undertaken to determine the potentialities of chlorine dioxide as an algaecide and as an agent for the removal of tastes and odors from fresh water.

Mycobacterium avium, an opportunistic human pathogen, infects between 25 and 50% of advanced-stage acquired immuno-deficiency syndrome (AIDS) patients in the United States. M. avium has been isolated from many environmental sources including: natural waters, soils, and aerosols. M. avium has also been recovered from within municipal and hospital drinking water systems. Rhesus macaques (Macaca mulatta) infected with the simian HIV analog, SIV, have been shown to acquire M. avium infections from potable water. Reduced-aggregate fractions (cell suspensions free of large aggregates) of Mycobacterium avium were exposed to chlorine, monochloramine, chlorine dioxide, and ozone and kinetics of disinfection measured. Chlorine disinfection kinetics was also measured in M. avium cultures grown in biofilms. M. avium exhibited a high resistance to chlorine compared to E. coli. M. avium CT99.9% (disinfectant concentration x time to 3 logs cell inactivation) values were between 571- and 2318 -times those of E. coli. Clinical isolates of M. avium showed 0.24 and 2.5-fold increase in resistance to chlorine compared to their pulsed-field-gel-electrophoresis- (PFGE) matched environmental isolates. M. avium strains exhibited a mixed response to exposure to monochloramine. The CT99.9% values of three strains (2 clinical, 1 environmental) were between 6.3- and 23.5- times that of E. coli. Two strains (1 clinical, 1 environmental) exhibited CT99.9% values approximately the same as E. coli, a difference from all the other disinfectants which were much less effective on M. avium than on E. coli. M. avium strains exhibited a high resistance to chlorine dioxide when compared to E.coli. M. avium CT99.9% values of between 133- and 706- times higher that that of E. coli. In the paired isolates tested, the clinical isolate was 5.3 times more resistant than the matched environmental isolate. M. avium exhibited a high resistance to ozone when compared to E. coli. M. avium strains exhibited a CT99.9% value of between 52 and 90 times higher that that of E. coli. In the paired isolates tested, the clinical isolate was nearly identical as judged by CT99.9% values. M. avium strain 5002 exhibited an unusual disinfection kinetics curve. Disinfection rate increased by a non-logarithmic factor, indicating that inactivation efficiency was increasing over time. M. avium strain 1060 showed between a 17% decrease to a 265% increase in CT99.9% value when grown as biofilms as opposed to suspension. Due to the large variance in biofilm density and and CT99.9% values, any conclusions based on these experiments should be considered tentative at best. M. avium's resistance to chlorine and chlorine dioxide approaches that of the protozoan cysts of Giardia muris and Entamoeba hystolytica. M. avium is much less resistant, relatively, to monochloramine possessing values similar to E. coli. Ozone resistance of M. avium is two orders of magnitude greater than E. coli and one order of magnitude of less than G. muris cysts. A critical concentration threshold level for chlorine dioxide was found. That is, there was no linear relationship between concentration of chlorine dioxide and cell inactivation. Initial experiments using a range of concentrations from 0.1 ppm to 0.5 ppm chlorine dioxide showed a biphasic curve with the inflection point (indicating the critical concentration) between 0.3 and 0.4 ppm chlorine dioxide. / Master of Science

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No description available.