Relationship between sine random vibrations, resonance and drug content uniformity.

The effect of sine random vibrations on the segregation tendency of 3 ordered power mixes was studied. Ordered mixes containing either Emdex, Dipac or recrystallized lactose carrier particles mixed with 0.5% fine-particle potassium chloride were prepared. It was found that the coefficients of variation of drug content in samples removed from the ordered mixes following random vibration were, in general, lower than those derived from vibration at equivalent single frequencies. Ordered mixes vibrated at low centre-frequencies were found to be most prone to slight demixing and under these conditions, a vibration bandwidth of 30 Hz produced more de-mixing than a 10 Hz bandwidth. Most ordered mixes were considered to be segregation free following random vibration.