Natalija Škrbina Zajc - Academia.edu (original) (raw)

Uploads

Papers by Natalija Škrbina Zajc

Research paper thumbnail of Improvement of ascorbyl palmitate stability in lipid nanoparticle dispersions for dermal use

Journal of Drug Delivery Science and Technology, 2006

The aim of this work was to investigate and compare the stability of ascorbyl palmitate (AP) in n... more The aim of this work was to investigate and compare the stability of ascorbyl palmitate (AP) in nanoemulsions (NE), solid lipid nanoparticle (SLN) dispersions and oil-loaded SLN (also described as nanostructured lipid carriers, NLC) dispersions of different compositions and stored under different conditions. The SLN and NLC dispersions investigated showed no greater protection of AP from the aqueous environment than nanoemulsions. AP being significantly more stable in formulations from which oxygen had been removed by degassing with argon after preparation. The stability of AP in NLC is influenced most by the total lipid concentration and the type of phospholipid. Higher lipid concentrations and hydrogenated phospholipid in dispersions offer better protection. After one month there was still 85% of non-degraded AP in formulation which contains hydrogenated phospholipid and 10% of lipid. AP stability therefore depends on appropriate selection of concentration and type of lipid, the selection of non-oxidizable components of the carrier system and appropriate choice of storage conditions.

Research paper thumbnail of Characterization of Calcium Alginate Beads Containing Structurally Similar Drugs

Drug Development and Industrial Pharmacy, 2006

Research paper thumbnail of Polymorphic forms of ziprasidone sulphate salts

Research paper thumbnail of Polymorphic forms of ziprasidone sulphates

Research paper thumbnail of Assesment of felodipine glass transition behaviour using modulted temperature differential scanning calorimetry

Acta Chimica Slovenica, 2002

Glassy felodipine samples have been investigated thermoanalytically by means of modulated tempera... more Glassy felodipine samples have been investigated thermoanalytically by means of modulated temperature differential scanning calorimetry (MTDSC). The method advantage of improved signal to noise ratio is confirmed and the glass transition is determined independently from the relaxation phenomena. Experiments with linear saw-tooth modulation with different experimental parameters revealed the strong influence of the modulation period on the data derived. The activation energy of the felodipine glass transition is calculated, introducing different value as determined previously.

Research paper thumbnail of Physical properties and dissolution behaviour of nifedipine/mannitol solid dispersions prepared by hot melt method

International Journal of Pharmaceutics, 2005

Research paper thumbnail of Esomeprazole arginine salt

Research paper thumbnail of Polymorphic forms of ziprasidone sulfates

Research paper thumbnail of Solid dosage forms comprising aliskiren and pharmaceutically acceptable salts thereof

Research paper thumbnail of GASTRO-RESISTANT PHARMACEUTICAL ORAL COMPOSITIONS COMPRISING DULOXETINE OR ITS PHARMACEUTICALLY ACCEPTABLE DERIVATIVES

Research paper thumbnail of SYNTHESIS OF DULOXETINE AND/OR PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF

Research paper thumbnail of Crystalline forms of duloxetine hydrochloride and processes for their preparation

Research paper thumbnail of Esomeprazole arginine salt

Research paper thumbnail of Processes for the preparation of crystalline forms of duloxetine hydrochloride

Research paper thumbnail of Binary melting phase diagrams of nifedipine-PEG 4000 and nifedipine-mannitol systems

... and I. ErÞs, J. Therm. Anal. Cal., 68 (2002) 503. 9 DQM Craig and JM Newton, Int. J. Pharm., ... more ... and I. ErÞs, J. Therm. Anal. Cal., 68 (2002) 503. 9 DQM Craig and JM Newton, Int. J. Pharm., 74 (1991) 33. ... 12 A. Burger and KT Koller, Sci. Pharm., 64 (1996) 293. 13 A. Burger, JO Henck, S. Hetz, JM Rollinger, AA Weissnicht and E. Stöttner, J. Pharm. Sci., 89 (2000) 457. ...

Research paper thumbnail of Binary melting phase diagrams of nifedipine-PEG 4000 and nifedipine-mannitol systems

Journal of Thermal Analysis and Calorimetry, 2000

... and I. ErÞs, J. Therm. Anal. Cal., 68 (2002) 503. 9 DQM Craig and JM Newton, Int. J. Pharm., ... more ... and I. ErÞs, J. Therm. Anal. Cal., 68 (2002) 503. 9 DQM Craig and JM Newton, Int. J. Pharm., 74 (1991) 33. ... 12 A. Burger and KT Koller, Sci. Pharm., 64 (1996) 293. 13 A. Burger, JO Henck, S. Hetz, JM Rollinger, AA Weissnicht and E. Stöttner, J. Pharm. Sci., 89 (2000) 457. ...

Research paper thumbnail of Physical properties and dissolution behaviour of nifedipine/mannitol solid dispersions prepared by hot melt method

International Journal of Pharmaceutics, 2005

Solid dispersions of nifedipine (NIF) with mannitol in preparations containing 10 and 50% (w/w) o... more Solid dispersions of nifedipine (NIF) with mannitol in preparations containing 10 and 50% (w/w) of drug were manufactured by the hot melt method. Physical properties and the dissolution behaviour of binary systems as physical mixtures and solid dispersions were investigated. In all samples, the crystal structure of NIF was confirmed using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) revealed, there was no interaction between drug and carrier, however, FTIR spectra indicated formation of thermodynamically less stable polymorph of mannitol. The dissolution rate of NIF from solid dispersions was markedly enhanced, the effect being stronger at higher drug loading (50%, w/w, NIF). The dissolution rate enhancement was attributed to improved wetting of NIF crystals due to mannitol particles, attached on the surface, as inspected by means of SEM. Thermal stability of NIF, mannitol and two other potential carbohydrate carriers (lactose and saccharose) during the hot melt procedure was investigated using 1 H NMR. NIF was found to be thermically stable under conditions applied. As expected, among carriers only mannitol demonstrated suitable resistance to high temperature used in experiments.

Research paper thumbnail of Improvement of ascorbyl palmitate stability in lipid nanoparticle dispersions for dermal use

Journal of Drug Delivery Science and Technology, 2006

The aim of this work was to investigate and compare the stability of ascorbyl palmitate (AP) in n... more The aim of this work was to investigate and compare the stability of ascorbyl palmitate (AP) in nanoemulsions (NE), solid lipid nanoparticle (SLN) dispersions and oil-loaded SLN (also described as nanostructured lipid carriers, NLC) dispersions of different compositions and stored under different conditions. The SLN and NLC dispersions investigated showed no greater protection of AP from the aqueous environment than nanoemulsions. AP being significantly more stable in formulations from which oxygen had been removed by degassing with argon after preparation. The stability of AP in NLC is influenced most by the total lipid concentration and the type of phospholipid. Higher lipid concentrations and hydrogenated phospholipid in dispersions offer better protection. After one month there was still 85% of non-degraded AP in formulation which contains hydrogenated phospholipid and 10% of lipid. AP stability therefore depends on appropriate selection of concentration and type of lipid, the selection of non-oxidizable components of the carrier system and appropriate choice of storage conditions.

Research paper thumbnail of Characterization of Calcium Alginate Beads Containing Structurally Similar Drugs

Drug Development and Industrial Pharmacy, 2006

Research paper thumbnail of Polymorphic forms of ziprasidone sulphate salts

Research paper thumbnail of Polymorphic forms of ziprasidone sulphates

Research paper thumbnail of Assesment of felodipine glass transition behaviour using modulted temperature differential scanning calorimetry

Acta Chimica Slovenica, 2002

Glassy felodipine samples have been investigated thermoanalytically by means of modulated tempera... more Glassy felodipine samples have been investigated thermoanalytically by means of modulated temperature differential scanning calorimetry (MTDSC). The method advantage of improved signal to noise ratio is confirmed and the glass transition is determined independently from the relaxation phenomena. Experiments with linear saw-tooth modulation with different experimental parameters revealed the strong influence of the modulation period on the data derived. The activation energy of the felodipine glass transition is calculated, introducing different value as determined previously.

Research paper thumbnail of Physical properties and dissolution behaviour of nifedipine/mannitol solid dispersions prepared by hot melt method

International Journal of Pharmaceutics, 2005

Research paper thumbnail of Esomeprazole arginine salt

Research paper thumbnail of Polymorphic forms of ziprasidone sulfates

Research paper thumbnail of Solid dosage forms comprising aliskiren and pharmaceutically acceptable salts thereof

Research paper thumbnail of GASTRO-RESISTANT PHARMACEUTICAL ORAL COMPOSITIONS COMPRISING DULOXETINE OR ITS PHARMACEUTICALLY ACCEPTABLE DERIVATIVES

Research paper thumbnail of SYNTHESIS OF DULOXETINE AND/OR PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF

Research paper thumbnail of Crystalline forms of duloxetine hydrochloride and processes for their preparation

Research paper thumbnail of Esomeprazole arginine salt

Research paper thumbnail of Processes for the preparation of crystalline forms of duloxetine hydrochloride

Research paper thumbnail of Binary melting phase diagrams of nifedipine-PEG 4000 and nifedipine-mannitol systems

... and I. ErÞs, J. Therm. Anal. Cal., 68 (2002) 503. 9 DQM Craig and JM Newton, Int. J. Pharm., ... more ... and I. ErÞs, J. Therm. Anal. Cal., 68 (2002) 503. 9 DQM Craig and JM Newton, Int. J. Pharm., 74 (1991) 33. ... 12 A. Burger and KT Koller, Sci. Pharm., 64 (1996) 293. 13 A. Burger, JO Henck, S. Hetz, JM Rollinger, AA Weissnicht and E. Stöttner, J. Pharm. Sci., 89 (2000) 457. ...

Research paper thumbnail of Binary melting phase diagrams of nifedipine-PEG 4000 and nifedipine-mannitol systems

Journal of Thermal Analysis and Calorimetry, 2000

... and I. ErÞs, J. Therm. Anal. Cal., 68 (2002) 503. 9 DQM Craig and JM Newton, Int. J. Pharm., ... more ... and I. ErÞs, J. Therm. Anal. Cal., 68 (2002) 503. 9 DQM Craig and JM Newton, Int. J. Pharm., 74 (1991) 33. ... 12 A. Burger and KT Koller, Sci. Pharm., 64 (1996) 293. 13 A. Burger, JO Henck, S. Hetz, JM Rollinger, AA Weissnicht and E. Stöttner, J. Pharm. Sci., 89 (2000) 457. ...

Research paper thumbnail of Physical properties and dissolution behaviour of nifedipine/mannitol solid dispersions prepared by hot melt method

International Journal of Pharmaceutics, 2005

Solid dispersions of nifedipine (NIF) with mannitol in preparations containing 10 and 50% (w/w) o... more Solid dispersions of nifedipine (NIF) with mannitol in preparations containing 10 and 50% (w/w) of drug were manufactured by the hot melt method. Physical properties and the dissolution behaviour of binary systems as physical mixtures and solid dispersions were investigated. In all samples, the crystal structure of NIF was confirmed using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) revealed, there was no interaction between drug and carrier, however, FTIR spectra indicated formation of thermodynamically less stable polymorph of mannitol. The dissolution rate of NIF from solid dispersions was markedly enhanced, the effect being stronger at higher drug loading (50%, w/w, NIF). The dissolution rate enhancement was attributed to improved wetting of NIF crystals due to mannitol particles, attached on the surface, as inspected by means of SEM. Thermal stability of NIF, mannitol and two other potential carbohydrate carriers (lactose and saccharose) during the hot melt procedure was investigated using 1 H NMR. NIF was found to be thermically stable under conditions applied. As expected, among carriers only mannitol demonstrated suitable resistance to high temperature used in experiments.