A simple suspension method has been developed for the administration of tablets and capsules by tube in which the tablets or capsules are allowed to disintegrate in hot water (55°C) without grinding or opening. However, since the stability of drugs at 55°C has been a matter of concern, in the present study, we investigated drug stability for 8 agents which are frequently administered by tube. Recovery was compared between the simple suspension method and the conventional crushing method, and the stability of each drug after making suspensions of several drugs at the same time was also investigated.
For the simple suspension method, the recovery of each drug was nearly 100% at 10 min and 2 hrs after making the suspensions. Recovery was also almost 100% on making a suspension of 3 agents at the same time. However, by the conventional crushing method, recovery for some drugs was less than 90%, with that for zonisamide being as low as 59%. This could be due to the adherence of drugs during the grinding, mixing and packaging processes.
In conclusion, the simple suspension method was considered to be a valid method of suspension since the tested drugs were stable in hot water at the temperature used for the simple suspension method. It was also considered to be valid in terms of reduced variability in the actual dosage compared with the conventional crushing method.