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Gulsu A.,Mugla University | Ayhan H.,Biochemist and Bioengeneer | Ayhan F.,Mugla University
Turkish Journal of Biochemistry | Year: 2012

Aim: Albumin microspheres have found many applications in the diagnosis and treatment in recent years and more than 100 diagnostic agents and drugs have been incorporated into Albumin microspheres. The objective of this study was to investigate the effect of preparation parameters (Albumin concentration, stirring rate, crosslinker amount, crosslinking time) on the Albumin microsphere size and determine the release profile of ketoprofen loaded albumin microsphere. Method: Albumin microspheres were prepared by an emulsion polymerization method using glutaraldehyde (GA) as the crosslinking agent. The prepared microspheres were then studied for their particle size, size distribution, release characteristics. The microspheres were characterized using an Optical Microscope. Results: The microspheres had mean diameters between 2-25 μm of which more than 25 percent were below 10 μm. Drug release from the Albumin microspheres displayed a biphasic pattern characterized by an initial fast release, followed by a slower release. The total amount of drug released from microspheres in pH 7.4 phosphate buffer saline (PBS) at 37°C after 180 min was obtained as 33%. Conclusion: In the present study the various parameters affecting the characteristics of the albumin microspheres were evaluated. According to these results optimal conditions were determined as: 0.1 mg.ml-1 Albumin concentration, 1000 rpm stirring rate, 1% GA amonut and 30 min crosslinking time. The drug release from Albumin microspheres was mainly controlled by diffusion and showed a biphasic pattern with initial release (burst effect), followed by a slow and controlled release phase resulting from controlled diffusion of the entrapped drug. Additionally, local gastrointestinal side effects are thought to be reduced by sustained release of ketoprofen and this must also be investigated with in vivo experiments. © TurkJBiochem.com.

Ayhan H.,Biochemist and Bioengeneer | Ayhan H.,Mugla University | Ayhan F.,Biochemist and Bioengeneer | Ayhan F.,Mugla University | And 2 more authors.
Turkish Journal of Biochemistry | Year: 2012

Aim: The purpose of the work is the use of L-Lysine amino acid cross-linker in the achievement of alternative and compatible enzyme aggregate. Cross-linked enzyme aggregates (CLEAs) were prepared from several enzymes (glucose oxidase, peroxidase and urease) by precipitation and subsequent cross-linking using glutaraldehyde, 1,8-octanediamine and L-Lysine. Material and Methods: The effects of cross-linking agents on CLEAs activity were investigated and immobilized enzymes were characterized. The initial enzyme concentration was constant as 4x10 -3 mg/ml. BSA were used as precipitant in CLEA's method as described in our previously study. Results: The concentration of cross-linkers were 2% for glutaraldehyde and 1,8-octanediamine and 4% for L-Lysine. Activities of both free and immobilised enzymes were obtained by measuring the amount of substrate conversion, spectrophotometrically. Kinetic parameters of native and immobilised enzyme were calculated by using Lineweaver-Burk plots. Conclusion: L-Lysine was applied successfully as a cross-linker for the formation of CLEA's. © TurkJBiochem.com.

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