ABSTRACT:16 17Spin-freezing as alternative freezing approach was evaluated as part of an innovative 18 continuous pharmaceutical freeze-drying concept for unit doses. The aim of this paper 19 was to compare the sublimation rate of spin-frozen vials versus traditionally frozen vials 20 in a batch freeze-dryer, and its impact on total drying time.
21Five different formulations, each having a different dry cake resistance, were tested.
23After freezing, the traditionally frozen vials were placed on the shelves while the spin-24 frozen vials were placed in aluminium vial holders providing radial energy supply during 25 drying. Different primary drying conditions and chamber pressures were evaluated.
26After two hours of primary drying, the amount of sublimed ice was determined in each 27 vial. Each formulation was monitored in-line using NIR spectroscopy during drying to
Bacteria reside within biofilms at the infection site, making them extremely difficult to eradicate with conventional wound care products. Bacteria use quorum sensing (QS) systems to regulate biofilm formation, and QS inhibitors (QSIs) have been proposed as promising antibiofilm agents. Despite this, few antimicrobial therapies that interfere with QS exist. Nontoxic hydroxypropyl-β-cyclodextrin-functionalized cellulose gauzes releasing a burst of the antibiotic vancomycin and the QSI hamamelitannin are developed, followed by a sustained release of both. The gauzes affect QS and biofilm formation of Pseudomonas aeruginosa and Staphylococcus aureus in an in vitro model of chronic wound infection and can be considered as candidates to be used to prevent wound infection as well as treat infected wounds.
Background: Lethal and sublethal effects of azadirachtin were studied on Bombus terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator.Results: Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg litre , azadirachtin significantly inhibited the egg laying and, consequently, the production of drones during 6 weeks. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the sublethal effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg litre -1 . Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration.Conclusion: Azadirachtin can affect B. terrestris with a range of sublethal effects. This study confirms the need to test compounds on their safety, especially when they have to perform complex tasks such as foraging.
Recently, an innovative continuous freeze-drying concept for unit doses was proposed, based on spinning the vials during freezing. An efficient heat transfer during drying is essential to continuously process these spin frozen vials. Therefore, the applicability of non-contact infrared (IR) radiation was examined. The impact of several process and formulation variables upon the mass of sublimed ice after 15 minutes of primary drying (i.e., sublimation rate) and the total drying time was examined. Two experimental designs were performed in which electrical power to the IR heaters, distance between the IR heaters and the spin frozen vial, chamber pressure, product layer thickness and five model formulations were included as factors. A near-infrared (NIR) spectroscopy method was developed to determine the endpoint of primary and secondary drying. The sublimation rate was mainly influenced by the electrical power to the IR heaters and the distance between the IR heaters and the vial. The layer thickness had the largest effect on total drying time. The chamber pressure and the five model formulations had no significant impact on sublimation rate and total drying time, respectively. This study shows that IR radiation is suitable to provide the energy during the continuous processing of spin frozen vials.
The UGent Institutional Repository is the electronic archiving and dissemination platform for all UGent research publications. Ghent University has implemented a mandate stipulating that all academic publications of UGent researchers should be deposited and archived in this repository. Except for items where current copyright restrictions apply, these papers are available in Open Access. This item is the archived peer-reviewed author-version of: Thermal imaging as a noncontact inline process analytical tool for product temperature monitoring during continuous freezedrying of unit dose
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