The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform

Gökhan Ertan - One of the best experts on this subject based on the ideXlab platform.

  • The effect of geometric shape on the release properties of metronidazole from lipid matrix tablets.
    Journal of biomedical nanotechnology, 2009
    Co-Authors: Evren Gökçe, Mine Özyazici, Gökhan Ertan
    Abstract:

    In this study, the lipophilic matrix tablets of metronidazole were prepared with Cutina HR (hydrogenated castor oil), stearic acid, Compritol ATO 888 (glyceryl behenate) and Precirol ATO 5 (Glycerol Palmitostearate) in two different shapes; cylinder and hexagonal. Our first aim was to investigate the influence of the lipid excipients and geometric shape on the release behavior of metronidazole, and the second aim was to investigate the influence of tablet surface area/volume (SA/V) ratio on drug release from controlled release matrix tablets. In vitro release test was performed using a standard USP dissolution apparatus I. Hardness, surface/volume ratio and friability were determined. The hexagonal tablets were harder than the cylinder tablets. Stearic acid showed the highest release rates for both geometric shapes reflecting the highest surface area and the lowest SA/V ratio. According to power law analysis, the diffusion mechanism was expressed as a Fickian diffusion for all lipid matrix tablets. The square root of time relationship was operative for all tablets. Higuchi kinetic constants obtained with hexagonal tablets were higher than the cylinder tablets. As the type of lipid matrix, the geometric shape of the tablets was also effective on the diffusion and release kinetics. From the present study, it was shown that surface area and volume ratio may be used as parameters for the evaluation of the drug release profile.

Evren Gökçe - One of the best experts on this subject based on the ideXlab platform.

  • The effect of geometric shape on the release properties of metronidazole from lipid matrix tablets.
    Journal of biomedical nanotechnology, 2009
    Co-Authors: Evren Gökçe, Mine Özyazici, Gökhan Ertan
    Abstract:

    In this study, the lipophilic matrix tablets of metronidazole were prepared with Cutina HR (hydrogenated castor oil), stearic acid, Compritol ATO 888 (glyceryl behenate) and Precirol ATO 5 (Glycerol Palmitostearate) in two different shapes; cylinder and hexagonal. Our first aim was to investigate the influence of the lipid excipients and geometric shape on the release behavior of metronidazole, and the second aim was to investigate the influence of tablet surface area/volume (SA/V) ratio on drug release from controlled release matrix tablets. In vitro release test was performed using a standard USP dissolution apparatus I. Hardness, surface/volume ratio and friability were determined. The hexagonal tablets were harder than the cylinder tablets. Stearic acid showed the highest release rates for both geometric shapes reflecting the highest surface area and the lowest SA/V ratio. According to power law analysis, the diffusion mechanism was expressed as a Fickian diffusion for all lipid matrix tablets. The square root of time relationship was operative for all tablets. Higuchi kinetic constants obtained with hexagonal tablets were higher than the cylinder tablets. As the type of lipid matrix, the geometric shape of the tablets was also effective on the diffusion and release kinetics. From the present study, it was shown that surface area and volume ratio may be used as parameters for the evaluation of the drug release profile.

Mine Özyazici - One of the best experts on this subject based on the ideXlab platform.

  • The effect of geometric shape on the release properties of metronidazole from lipid matrix tablets.
    Journal of biomedical nanotechnology, 2009
    Co-Authors: Evren Gökçe, Mine Özyazici, Gökhan Ertan
    Abstract:

    In this study, the lipophilic matrix tablets of metronidazole were prepared with Cutina HR (hydrogenated castor oil), stearic acid, Compritol ATO 888 (glyceryl behenate) and Precirol ATO 5 (Glycerol Palmitostearate) in two different shapes; cylinder and hexagonal. Our first aim was to investigate the influence of the lipid excipients and geometric shape on the release behavior of metronidazole, and the second aim was to investigate the influence of tablet surface area/volume (SA/V) ratio on drug release from controlled release matrix tablets. In vitro release test was performed using a standard USP dissolution apparatus I. Hardness, surface/volume ratio and friability were determined. The hexagonal tablets were harder than the cylinder tablets. Stearic acid showed the highest release rates for both geometric shapes reflecting the highest surface area and the lowest SA/V ratio. According to power law analysis, the diffusion mechanism was expressed as a Fickian diffusion for all lipid matrix tablets. The square root of time relationship was operative for all tablets. Higuchi kinetic constants obtained with hexagonal tablets were higher than the cylinder tablets. As the type of lipid matrix, the geometric shape of the tablets was also effective on the diffusion and release kinetics. From the present study, it was shown that surface area and volume ratio may be used as parameters for the evaluation of the drug release profile.

Ertan G. - One of the best experts on this subject based on the ideXlab platform.

  • The effect of geometric shape on the release properties of metronidazole from lipid matrix tablets
    'American Scientific Publishers', 2009
    Co-Authors: Gökçe E.h., Özyazici M., Ertan G.
    Abstract:

    PubMed ID: 20055089In this study, the lipophilic matrix tablets of metronidazole were prepared with Cutina HR (hydrogenated castor oil), stearic acid, Compritol ATO 888 (glyceryl behenate) and Precirol ATO 5 (Glycerol Palmitostearate) in two different shapes; cylinder and hexagonal. Our first aim was to investigate the influence of the lipid excipients and geometric shape on the release behavior of metronidazole, and the second aim was to investigate the influence of tablet surface area/volume (SA/V) ratio on drug release from controlled release matrix tablets. In vitro release test was performed using a standard USP dissolution apparatus I. Hardness, surface/volume ratio and friability were determined. The hexagonal tablets were harder than the cylinder tablets. Stearic acid showed the highest release rates for both geometric shapes reflecting the highest surface area and the lowest SA/V ratio. According to power law analysis, the diffusion mechanism was expressed as a Fickian diffusion for all lipid matrix tablets. The square root of time relationship was operative for all tablets. Higuchi kinetic constants obtained with hexagonal tablets were higher than the cylinder tablets. As the type of lipid matrix, the geometric shape of the tablets was also effective on the diffusion and release kinetics. From the present study, it was shown that surface area and volume ratio may be used as parameters for the evaluation of the drug release profile. Copyright © 2009 American Scientific Publishers All rights reserved

Natalie J. Medlicott - One of the best experts on this subject based on the ideXlab platform.

  • Investigation on Secondary Structure Perturbations of Proteins Embedded in Solid Lipid Matrices as a Novel Indicator of their Biological Activity upon In Vitro Release
    AAPS PharmSciTech, 2018
    Co-Authors: Farrukh Zeeshan, Misbah Tabbassum, Lene Jorgensen, Natalie J. Medlicott
    Abstract:

    Protein biologics are prone to conformational changes during formulation development. Limited methods are available for conformational analysis of proteins in solid state and in the presences of formulation excipients. The aim of this study was to investigate the secondary structures of proteins encased in solid lipid matrices as a novel indicator of their stability upon in vitro release. Model proteins namely catalase and lysozyme were incorporated into lipid namely Precirol® AT05 (Glycerol Palmitostearate, melting point 58°C) at 30% w / w loading using melting and mixing and wet granulation methods. Attenuated total reflectance (ATR-FTIR) spectroscopy, size-exclusion chromatography (SEC) and biological activity analyses were performed. The information about secondary structure was acquired using second derivative analysis of amide-I band (1600–1700 cm^−1). ATR analysis demonstrated interference of lipid spectrum with protein amide-I band which was subsequently subtracted to allow the analysis of the secondary structure. ATR spectra amide-I bands showed shifts peak band positions compared to native protein for matrices prepared using wet granulation. SEC analysis gave evidence of protein aggregation for catalase which was increased using wet granulation. The biological activity of catalase was statistically different from that of control and was affected by the incorporation method and was found to be in alignment with ATR spectral changes and extent of aggregation. In conclusion, ATR spectroscopy could analyze protein secondary structure in lipid matrices provided lipid interference was minimized. The ATR spectral changes and formation of aggregates can indicate the loss in biological activity of protein released from solid lipid matrices.

  • attenuated total reflection fourier transform infrared atr ft ir spectroscopy as an analytical method to investigate the secondary structure of a model protein embedded in solid lipid matrices
    Applied Spectroscopy, 2018
    Co-Authors: Farrukh Zeeshan, Misbah Tabbassum, Lene Jorgensen, Natalie J. Medlicott
    Abstract:

    Protein drugs may encounter conformational perturbations during the formulation processing of lipid-based solid dosage forms. In aqueous protein solutions, attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy can investigate these conformational changes following the subtraction of spectral interference of solvent with protein amide I bands. However, in solid dosage forms, the possible spectral contribution of lipid carriers to protein amide I band may be an obstacle to determine conformational alterations. The objective of this study was to develop an ATR FT-IR spectroscopic method for the analysis of protein secondary structure embedded in solid lipid matrices. Bovine serum albumin (BSA) was chosen as a model protein, while Precirol AT05 (Glycerol Palmitostearate, melting point 58 ℃) was employed as the model lipid matrix. Bovine serum albumin was incorporated into lipid using physical mixing, melting and mixing, or wet granulation mixing methods. Attenuated total reflection FT-IR spectroscopy and size exclusion chromatography (SEC) were performed for the analysis of BSA secondary structure and its dissolution in aqueous media, respectively. The results showed significant interference of Precirol ATO5 with BSA amide I band which was subtracted up to 90% w/w lipid content to analyze BSA secondary structure. In addition, ATR FT-IR spectroscopy also detected thermally denatured BSA solid alone and in the presence of lipid matrix indicating its suitability for the detection of denatured protein solids in lipid matrices. Despite being in the solid state, conformational changes occurred to BSA upon incorporation into solid lipid matrices. However, the extent of these conformational alterations was found to be dependent on the mixing method employed as indicated by area overlap calculations. For instance, the melting and mixing method imparted negligible effect on BSA secondary structure, whereas the wet granulation mixing method promoted more changes. Size exclusion chromatography analysis depicted the complete dissolution of BSA in the aqueous media employed in the wet granulation method. In conclusion, an ATR FT-IR spectroscopic method was successfully developed to investigate BSA secondary structure in solid lipid matrices following the subtraction of lipid spectral interference. The ATR FT-IR spectroscopy could further be applied to investigate the secondary structure perturbations of therapeutic proteins during their formulation development.