Limitations of compounding diazepam suspensions from tablets.

The concentration of diazepam in two types of suspension vehicles, as prepared from 10-mg tablets was tested over a 14-day period. The suspensions (1 mg/ml) were stored at room temperature in amber glass bottles. In one suspension, consisting of eight triturated tablets, 4.0 ml ethanol, 24.0 ml propylene glycol, 20.0 ml Syrup, USP, and 32.0 ml chocolate syrup, 90% of the diazepam was dissolved. This suspension demonstrated consistently acceptable concentrations of diazepam. In the other suspension, consisting of triturated tablets and Syrup, USP, only 25% of the diazepam was dissolved, and less consistent, subpotent concentrations of diazepam were found. The variation of diazepam concentrations between the suspensions was unrelated to the chemical stability of the drug.