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• W1541048219 abstract "This thesis is based on the investigation of the compression behavior of a solid model enzyme. Itwas the scope of this work to characterize the behavior of the enzyme powder under pressure togain on the one hand information about the behavior of powder during the compression processand on the other hand to get more knowledge about the behavior of enzyme powder inpharmaceutical formulations. An important aspect was the influence of excipients because theirdeformation character may change the properties of pharmaceutical formulations. For that reasonthe physical influences of a plastic and a brittle model excipient, respectively on the enzymepowder in binary mixtures was investigated. Critical mixture ratios should be defined where thebehavior of the binary mixtures shows sudden changes. If critical mixture ratios are known, theycan be avoided in the development of dosage forms to get robust formulations. Since the directcompaction of powders may be difficult, the compression behavior of enzyme granulates andenzyme coated pellets was investigated as well. For that reason powders and pellets from differentraw materials were layered with an enzyme binding agent solution. The enzyme activity of thevarious granulates, pellets and compacts was detected and the preparations were judged based onthis property. The investigated model enzyme was a solid β-galactosidase preparation from Aspergillus oryzae,which was chosen for its stability, the molecular weight of 105 kDa, which is an average valuecompared to other enzymes and the reliable and relatively simple enzyme activity assay.Compacts were produced on a material testing machine and the activity was detectedspectophotometrically. The compression properties of the various formulations were characterizedby using Heckel equation and modified Heckel equation. Granulates and pellets as well as theircompacts were further characterized by scanning electron microscopy pictures. The extent of activity loss in the compacted brittle enzyme powder could not be decreased by theaddition of a plastic or a brittle excipient. With the diversity of the particles even a higher number ofshearing forces was built in the compacts during compression. The shearing forces seemed tohave negative influences on the activity of the enzyme. In the binary powder mixtures of theenzyme powder with the plastic excipient there was found a sudden change in the behavior of thesystem at a mixture ratio of 20% of enzyme powder. For the brittle-brittle binary mixtures of theenzyme powder with an excipient, differences in the behavior were difficult to detect because thetwo powders showed a very similar behavior. Tendencies towards a critical concentration at a ratioof 60% (V/V) of enzyme powder could not be proved, although a comparison with a second brittleenzyme powder preparation in mixtures with a brittle excipient showed similar tendencies. It wasfound that a plastic compression character and regularity in shape and size of the compressedparticles was important to protect the enzyme activity under pressure. These properties could bereached with the production of granulates and the coating of pellets by enzyme layering, whereas especially the compacted enzyme coated pellets showed no significant activity loss under pressuredue to the very regular shape and size distribution and the fact that the pellets did not break andonly slightly changed their shape to reduce the spaces between the individual pellets.A lot of new aspects in the field of particle compression have been discussed in this work. It wasfound that the shape and the size of the various particles may have big influences on friction andshearing forces. Shearing forces can cause a reduction of enzyme activity during the compressionof an enzyme powder. The compression character of the particles showed influences on the extentof activity loss under pressure, whereas plastic properties are favorable to protect the enzyme.As a further step it would be important to test the transferability of the results on other enzymeproducts and to take into consideration more practical aspects like the production on a rotary press,the investigation of economic points of view or simply the attainment of a required dosage to definean optimal formulation for an oral application of a pharmaceutical enzyme powder." @default.
• W1541048219 created "2016-06-24" @default.
• W1541048219 creator A5058306423 @default.
• W1541048219 date "2004-01-01" @default.
• W1541048219 modified "2023-09-27" @default.
• W1541048219 title "Compression behavior of the enzyme ß-galactosidase" @default.
• W1541048219 doi "https://doi.org/10.5451/unibas-003232907" @default.
• W1541048219 hasPublicationYear "2004" @default.
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