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  • 1
    ISSN: 1573-904X
    Keywords: dissolution ; chewing gum ; phenylpropanolamine hydrochloride ; in vitro-in vivo correlation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A novel dissolution apparatus was developed for medicated chewing gum products. A prototype gum product containing phenylpropa-nolamine hydrochloride (PPA) was used to evaluate the apparatus. The apparatus consists of a conical Teflon base and a rotating, ribbed Teflon plunger suspended in a dissolution vessel. Parameters evaluated were rotation speed, plunger frequency, medium volume, medium type, medium sampling location, number of plunger ribs, and number of gum pieces. Samples were taken over a 20-min period and samples were analyzed by HPLC. Cumulative percentage re-leased-versus-time profiles were obtained for each parameter evaluated. Statistical analysis of the gum product indicated that the only significant differences occurred at the lowest rotation speed and lowest plunger frequencies. A Level A correlation was found between the in vitro release profile for the 20-rpm and 30-cycles/min plunger frequency and the in vivo chew-out study.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0006-3592
    Keywords: endocellulase ; exocellulase ; Thermomonospora fusca ; Trichoderma reesei ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The activities of six purified Thermomonospora fusca cellulases and Trichoderma reesei CBHI and CBHII were determined on filter paper, swollen cellulose, and CMC. A simple method to measure the soluble and insoluble reducing sugar products from the hydrolysis of filter paper was found to effectively distinguish between exocellulases and endocellulases. Endocellulases produced 34% to 50% insoluble reducing sugar and exocellulases produced less than 8% insoluble reducing sugar. The ability of a wide variety of mixtures of these cellulases to digest 5.2% of a filter paper disc in 16 h was measured quantitatively. The specific activities of the mixtures varied from 0.41 to 16.31 μmol cellobiose per minute per micromole enzyme. The degree of synergism ranged from 0.4 to 7.8. T. reesei CBHII and T. fusca E3 were found to be functionally equivalent in mixtures. The catalytic domains (cd) of T. fusca endocellulases E2 and E5 were purified and found to retain 93% and 100% of their CMC activity, respectively, but neither cd protein could digest filter paper to 5.2%. When E2cd and E5cd were substituted in synergistic mixtures for the native proteins, the mixtures containing E2cd retained 60%, and those containing E5cd retained 94% of the original activity. Addition of a β-glucosidase was found to double the activity of the best synergistic mixture. Addition of CBHI to T. fusca crude cellulase increased its activity on filter paper 1.7-fold. © 1993 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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