Jozef Peeters
Janssen Pharmaceutica
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Featured researches published by Jozef Peeters.
International Journal of Pharmaceutics | 2001
K. Six; Geert Verreck; Jozef Peeters; Patrick Augustijns; Renaat Kinget; G. Van den Mooter
The objective of the present study was to estimate the molecular mobility of glassy itraconazole below the glass transition, in comparison with structural analogues (i.e. miconazole and ketoconazole).Glassy itraconazole and miconazole were prepared by cooling from the melt. The glassy state of the drug was investigated with modulated temperature DSC using the following conditions: amplitude +/-0.212 K, period 40 s, underlying heating rate 2 K/min. The glass transition was determined from the reversing heat flow and occurred at 332.4 (+/-0.5) K and 274.8 (+/-0.4) K for itraconazole and miconazole, respectively. The jump in heat capacity at the glass transition was 303.42 (+/-3.43) J/mol K for itraconazole and 179.35 (+/-0.89) J/mol K for miconazole. The influence of the experimental conditions on the position of the glass transition of itraconazole was investigated by varying the amplitude from +/-0.133 to +/-0.292 K and the period from 25 to 55 s, while the underlying heating rate was kept constant at 2 K/min. Glass transition temperature, T(g), was not significantly influenced by the frequency of the modulation nor by the cooling rate. However, the relaxation enthalpy at the glass transition increased with decreasing cooling rate indicating relaxation during the glass formation process. To estimate the molecular mobility of the glassy materials, annealing experiments were performed from T(g)--10 to T(g)--40 K for periods ranging from 15 min to 16 h. Fitting the extent of relaxation of glassy itraconazole to the Williams--Watts decay function and comparing the obtained values with those of amorphous miconazole and ketoconazole indicated that the molecular mobility is influenced by the complexity of the molecular structure. The more complex the structure, the more stable the amorphous state.
Journal of Thermal Analysis and Calorimetry | 2002
K. Six; Ch. Leuner; Jennifer B. Dressman; Geert Verreck; Jozef Peeters; Norbert Blaton; Patrick Augustijns; Renaat Kinget; G. Van den Mooter
Solid dispersions of itraconazole and eudragit E100 were prepared by hot-stage extrusion. Analysis of the physical structure revealed the existence of different phases, depending on the manufacturing condition. Extrudates prepared at 453 K existed as a molecular dispersion of itraconazole in eudragit E100 when the drug concentration did not exceed ca. 13% mass/mass. At higher concentrations, a second phase consisting of pure glassy itraconazole emerged. In other dispersions prepared at 413 K, the second phase consisted of pure crystalline itraconazole. The difference can be attributed to the relation of the process-temperature to the melting point. Heating of both dispersions induced cold crystallization. Extrudates prepared at 453 K showed comparable behavior before and after milling, with the exception that unmilled dispersions with a drug load of ≥60% mass/mass recrystallized upon heating into a polymorphic modification of itraconazole (Tm=431 K). Upon further heating the polymorph recrystallized to the stable crystalline form (Tm=441 K).
Archive | 1996
Lieven Baert; Jozef Peeters; Geert Verreck
Archive | 1993
Jan Heeres; Jean Louis Mesens; Jozef Peeters
Archive | 2003
Roger Petrus Gerebern Vandecruys; Jozef Peeters; Marcus E. Brewster
Archive | 2003
Karel Six; Geert Verreck; Jozef Peeters; Marcus E. Brewster; Guy Van den Mooter
Archive | 2003
Roger Petrus Gerebern Vandecruys; Jozef Peeters; Marcus E. Brewster
Archive | 1996
Jan Heeres; Jean Louis Mesens; Jozef Peeters
Archive | 1996
Marcus Joannes Maria Noppe; Theo Cesar Garrevoet; Jozef Peeters; Jean-Louis Mesens
Archive | 1995
Jean Louis Mesens; Cauteren Herman Maria Jozef Van; Peter Putteman; Jozef Peeters