Sunita Victor - Academia.edu (original) (raw)

Papers by Sunita Victor

Research paper thumbnail of Stimuli Sensitive Polymethacrylic Acid Microparticles (PMAA) – Oral Insulin Delivery

Journal of Biomaterials Applications, 2002

This study investigated polymethacrylic acid (PMAA) microparticles for controlled release of Insu... more This study investigated polymethacrylic acid (PMAA) microparticles for controlled release of Insulin in oral administration. The microparticles were characterised by scanning electron microscopy (SEM) for morphological studies. The swelling behaviour and drug release profile in various pH media were studied. The % swelling of gels was found to be inversely related to the amount of crosslinker added. Inclusion complex of betaCD and Insulin was studied using polyacrylamide gel electrophoresis (PAGE). Optimum complexation was obtained in the ratio 100 mg betaCD: 200 IU Insulin. The release pattern of Insulin from Insulin-betaCD complex encapsulated PMAA microparticles showed release of Insulin for more than seven hours.

Research paper thumbnail of Development and evaluation of cyclodextrin complexed hydroxyapatite nanoparticles for preferential albumin adsorption

Colloids and Surfaces B-biointerfaces, 2011

Our study focuses on the incorporation of ␤-CD into the HA structure, its effects on the phase of... more Our study focuses on the incorporation of ␤-CD into the HA structure, its effects on the phase of HA and the biological responses to proteins and blood cells. Hydroxyapatite (HA) containing levels of ␤-cyclodextrin (␤-CD) of upto 0.9 wt% has been produced by co-precipitation method. The complexes were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TG) and differential scanning analysis (DSC) methods. The size of the complexes as analyzed using DLS (dynamic light scattering) was between 150 nm and 350 nm. The results show that an increase in concentration of ␤-CD in the prepared samples that leads to an increase in hydrophobicity seems to promote an affinity for albumin adsorption. The PAGE results were substantiated by Lowry measurements and the results reveal that the H2 (containing 0.7 wt% ␤-CD) sample shows around 40% increase in albumin adsorption when compared to the H1 (containing 0.5 wt% ␤-CD) sample. The preferential adsorption of albumin has not been demonstrated in vivo. The ability to design particles that can preferentially interact with particular protein can obtain desired targeting effects. So the results indicate that HA/␤-CD complexes have immense potential in targeted delivery of drugs. The in vivo potential of the developed samples was further confirmed in vitro by the results of cell aggregation and haemolytic activity.

Research paper thumbnail of Tryptophan complexed hydroxyapatite nanoparticles for immunoglobulin adsorption

Journal of Materials Science-materials in Medicine

The selective removal of immunoglobulin using different affinity–type particulate adsorbents has ... more The selective removal of immunoglobulin using different affinity–type particulate adsorbents has clinical significance in certain autoimmune diseases. This study reports the use of modified nanosized hydroxyapatite as a matrix for affinity based immunoglobulin adsorption. The adsorbent matrix consists of cyclodextrin complexed hydroxyapatite nanoparticles modified with tryptophan. It appears that presence of cyclodextrin has a synergic effect in the adsorption of immunoglobulin proteins having affinity with tryptophan complexed hydroxyapatite. The complexes were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TG) and differential scanning analysis (DSC) methods. The preferential affinity of the immunoglobulin towards tryptophan complexed particles was confirmed with polyacrylamide gel electrophoresis (PAGE) and Lowry adsorption techniques. Immunoglobulin adsorption was confirmed by quantitative turbidimetric assay using a standard immunoglobulin kit. The cytotoxicity index of the nanoparticle complexes were evaluated by MTT assay. Our proposed matrix for immunoglobulin adsorption is cost effective and adaptable for applications towards plasma perfusion.

Research paper thumbnail of BCP ceramic microspheres as drug delivery carriers: synthesis, characterisation and doxycycline release

Journal of Materials Science-materials in Medicine, 2008

Resorbable ceramics such as biphasic calcium phosphates (BCP) are ideal candidates as drug delive... more Resorbable ceramics such as biphasic calcium phosphates (BCP) are ideal candidates as drug delivery systems. The BCP ceramic is based on the optimum balance of the most stable hydroxyapatite (HA) phase and more soluble tricalcium phosphate phase (TCP). Doxycycline is a broad-spectrum antibiotic used for the local treatment of periodontitis. The development of BCP microspheres and its release kinetics with doxycycline have been studied. The BCP ceramic powder were prepared by microwave processing and characterised by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) methods. The BCP microspheres were formed by liquid immiscibility effect using gelatin and paraffin oil. Difference in the morphology of the microspheres as a function of gelatin content has been observed. Scanning electron microscope indicated spherical and porous morphology of the microspheres. Drug incorporation was studied at varying pH and the pH 7 was found to be optimal for drug loading. Release pattern tend to depend on the morphology of BCP microspheres. An optimum release of 80% drug has been observed for BCP microsphere with HA:TCP = 65:35 ratio. The surface area measurement results also correlate with drug release obtained.

Research paper thumbnail of Processing and properties of injectable porous apatitic cements

Journal of The Ceramic Society of Japan, 2008

ABSTRACT Injectable Calcium Phosphate Cements (CPC) are the emerging class of bone substitute mat... more ABSTRACT Injectable Calcium Phosphate Cements (CPC) are the emerging class of bone substitute materials as they can be moulded and shaped to fill intricate bone cavities and narrow dental sites. Various amounts of hydroxyapatite (HA) were mixed with tricalcium phosphate (TCP) using sodium hydrogen phosphate as the liquid medium. The formulations have a setting time of 15-30 min. These cements with setting time around 20 min, which is also clinically preferred, were found to have better wash out resistance. The X-ray diffraction method (XRD) and Fourier transform infrared spectroscopy (FT-IR) analysis confirmed HA as the setting phase. Gelatin has been incorporated to the selected formulations to induce porosity in the above selected cements. Scanning electron microscopy (SEM) reveals a macroporous structure as also confirmed by BET measurements. Injectability of the cement is being evaluated using chitosan.

Research paper thumbnail of Use of quartz crystal nanobalance to study the binding and stabilization of albumin and doxycycline on a thin layer of hydroxyapatite

Applied Surface Science

This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two mod... more This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two model molecules namely albumin and doxycycline by hydroxyapatite (HA). The work focuses on the deposition of a stable coating of HA on the quartz crystal, modification of the coating using doxycycline and its subsequent effects on albumin adsorption. The uniformity and thickness of the HA coating has been studied using atomic force microscopy (AFM). The functional groups to ascertain the presence of the selected moieties have been characterized by Raman spectroscopy. The results indicate that the mass of albumin deposited on the surface of the HA coated quartz crystal functionalized with doxycycline shows a substantial increase when compared to the standard HA coated quartz crystal. The adsorbed albumin has also been found to be retained for an enhanced period of time. This surface immobilization of doxycycline and subsequent albumin adsorption seem to be a promising approach to confer biomaterials with antithrombogenic and antibacterial surfaces.

Research paper thumbnail of Stimuli Sensitive Polymethacrylic Acid Microparticles (PMAA) – Oral Insulin Delivery

Journal of Biomaterials Applications, 2002

This study investigated polymethacrylic acid (PMAA) microparticles for controlled release of Insu... more This study investigated polymethacrylic acid (PMAA) microparticles for controlled release of Insulin in oral administration. The microparticles were characterised by scanning electron microscopy (SEM) for morphological studies. The swelling behaviour and drug release profile in various pH media were studied. The % swelling of gels was found to be inversely related to the amount of crosslinker added. Inclusion complex of betaCD and Insulin was studied using polyacrylamide gel electrophoresis (PAGE). Optimum complexation was obtained in the ratio 100 mg betaCD: 200 IU Insulin. The release pattern of Insulin from Insulin-betaCD complex encapsulated PMAA microparticles showed release of Insulin for more than seven hours.

Research paper thumbnail of Development and evaluation of cyclodextrin complexed hydroxyapatite nanoparticles for preferential albumin adsorption

Colloids and Surfaces B-biointerfaces, 2011

Our study focuses on the incorporation of ␤-CD into the HA structure, its effects on the phase of... more Our study focuses on the incorporation of ␤-CD into the HA structure, its effects on the phase of HA and the biological responses to proteins and blood cells. Hydroxyapatite (HA) containing levels of ␤-cyclodextrin (␤-CD) of upto 0.9 wt% has been produced by co-precipitation method. The complexes were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TG) and differential scanning analysis (DSC) methods. The size of the complexes as analyzed using DLS (dynamic light scattering) was between 150 nm and 350 nm. The results show that an increase in concentration of ␤-CD in the prepared samples that leads to an increase in hydrophobicity seems to promote an affinity for albumin adsorption. The PAGE results were substantiated by Lowry measurements and the results reveal that the H2 (containing 0.7 wt% ␤-CD) sample shows around 40% increase in albumin adsorption when compared to the H1 (containing 0.5 wt% ␤-CD) sample. The preferential adsorption of albumin has not been demonstrated in vivo. The ability to design particles that can preferentially interact with particular protein can obtain desired targeting effects. So the results indicate that HA/␤-CD complexes have immense potential in targeted delivery of drugs. The in vivo potential of the developed samples was further confirmed in vitro by the results of cell aggregation and haemolytic activity.

Research paper thumbnail of Tryptophan complexed hydroxyapatite nanoparticles for immunoglobulin adsorption

Journal of Materials Science-materials in Medicine

The selective removal of immunoglobulin using different affinity–type particulate adsorbents has ... more The selective removal of immunoglobulin using different affinity–type particulate adsorbents has clinical significance in certain autoimmune diseases. This study reports the use of modified nanosized hydroxyapatite as a matrix for affinity based immunoglobulin adsorption. The adsorbent matrix consists of cyclodextrin complexed hydroxyapatite nanoparticles modified with tryptophan. It appears that presence of cyclodextrin has a synergic effect in the adsorption of immunoglobulin proteins having affinity with tryptophan complexed hydroxyapatite. The complexes were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TG) and differential scanning analysis (DSC) methods. The preferential affinity of the immunoglobulin towards tryptophan complexed particles was confirmed with polyacrylamide gel electrophoresis (PAGE) and Lowry adsorption techniques. Immunoglobulin adsorption was confirmed by quantitative turbidimetric assay using a standard immunoglobulin kit. The cytotoxicity index of the nanoparticle complexes were evaluated by MTT assay. Our proposed matrix for immunoglobulin adsorption is cost effective and adaptable for applications towards plasma perfusion.

Research paper thumbnail of BCP ceramic microspheres as drug delivery carriers: synthesis, characterisation and doxycycline release

Journal of Materials Science-materials in Medicine, 2008

Resorbable ceramics such as biphasic calcium phosphates (BCP) are ideal candidates as drug delive... more Resorbable ceramics such as biphasic calcium phosphates (BCP) are ideal candidates as drug delivery systems. The BCP ceramic is based on the optimum balance of the most stable hydroxyapatite (HA) phase and more soluble tricalcium phosphate phase (TCP). Doxycycline is a broad-spectrum antibiotic used for the local treatment of periodontitis. The development of BCP microspheres and its release kinetics with doxycycline have been studied. The BCP ceramic powder were prepared by microwave processing and characterised by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) methods. The BCP microspheres were formed by liquid immiscibility effect using gelatin and paraffin oil. Difference in the morphology of the microspheres as a function of gelatin content has been observed. Scanning electron microscope indicated spherical and porous morphology of the microspheres. Drug incorporation was studied at varying pH and the pH 7 was found to be optimal for drug loading. Release pattern tend to depend on the morphology of BCP microspheres. An optimum release of 80% drug has been observed for BCP microsphere with HA:TCP = 65:35 ratio. The surface area measurement results also correlate with drug release obtained.

Research paper thumbnail of Processing and properties of injectable porous apatitic cements

Journal of The Ceramic Society of Japan, 2008

ABSTRACT Injectable Calcium Phosphate Cements (CPC) are the emerging class of bone substitute mat... more ABSTRACT Injectable Calcium Phosphate Cements (CPC) are the emerging class of bone substitute materials as they can be moulded and shaped to fill intricate bone cavities and narrow dental sites. Various amounts of hydroxyapatite (HA) were mixed with tricalcium phosphate (TCP) using sodium hydrogen phosphate as the liquid medium. The formulations have a setting time of 15-30 min. These cements with setting time around 20 min, which is also clinically preferred, were found to have better wash out resistance. The X-ray diffraction method (XRD) and Fourier transform infrared spectroscopy (FT-IR) analysis confirmed HA as the setting phase. Gelatin has been incorporated to the selected formulations to induce porosity in the above selected cements. Scanning electron microscopy (SEM) reveals a macroporous structure as also confirmed by BET measurements. Injectability of the cement is being evaluated using chitosan.

Research paper thumbnail of Use of quartz crystal nanobalance to study the binding and stabilization of albumin and doxycycline on a thin layer of hydroxyapatite

Applied Surface Science

This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two mod... more This study reports the use of quartz crystal nanobalance (QCN) to study the adsorption of two model molecules namely albumin and doxycycline by hydroxyapatite (HA). The work focuses on the deposition of a stable coating of HA on the quartz crystal, modification of the coating using doxycycline and its subsequent effects on albumin adsorption. The uniformity and thickness of the HA coating has been studied using atomic force microscopy (AFM). The functional groups to ascertain the presence of the selected moieties have been characterized by Raman spectroscopy. The results indicate that the mass of albumin deposited on the surface of the HA coated quartz crystal functionalized with doxycycline shows a substantial increase when compared to the standard HA coated quartz crystal. The adsorbed albumin has also been found to be retained for an enhanced period of time. This surface immobilization of doxycycline and subsequent albumin adsorption seem to be a promising approach to confer biomaterials with antithrombogenic and antibacterial surfaces.