Weak interactions in clobazam-lactose mixtures examined by differential scanning calorimetry: Comparison with the captopril-lactose system.

International audienceThe thermal behavior of binary mixts. of 2 drugs (clobazam and captopril, resp.) and a pharmaceutical excipient (lactose monohydrate) was measured with differential scanning calorimetry to det. thermodn. and kinetic parameters (dehydration and melting enthalpies and dehydration and glass-transition activation energies) which might be affected by intermol. interactions. A kinetic study showed that lactose dehydration is not a single-step conversion and that clobazam contributed to reduce the energy barrier for the bulk dehydration of the excipient. On the other hand, the phys. interactions between metastable liq. clobazam and cryst. anhyd. α-lactose obtained from monohydrate dehydration gave rise to the recrystn. of clobazam. In the captopril-lactose system, the liq. captopril influenced the lactose dehydration: a sharp increase of the dehydration enthalpy and a concurrent redn. of the dehydration temp. were obsd. Finally, it turned out that solid-phase transitions were enhanced by the contact with a liq. phase. [on SciFinder(R)

Stability of oral liquid preparations of methylergometrine

International audienceThe stability of an oral ready to-use form of methylergometrine (0.05 mg/mL), which provides a convenient volume for administration (5 mL), was evaluated over a forty-seven-day period at different temperatures (5 degrees C and room temperature) without light in order to assign a shelf life. Methylergometrine was assayed by a stability-indicating HPLC method with diode array detection. The drug undergoes degradation under basic conditions and dry heat (50 degrees C). All the peaks of the degraded product were resolved from the standard drug with significantly different retention times. Statistical analysis proves that the method is reproducible and accurate for estimation of the intact drug. The pH of samples was monitored periodically for changes. Samples were also visually inspected for any colour change, precipitation or crystallization. At least, 96% of the initial methylergometrine concentration remained throughout the 47-day study period. Over the test period, no significant change was observed in the pH or colour of any of the samples. No degradation products were revealed. This study allowed an oral ready to use solution of methylergometrine (0.05 mg/ml) to be prepared, with a shelf life of more than one month (47 days) when stored at room temperature without light

Is the choice between warfarin and fluindion important for patients?

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