Stability of hydralazine hydrochloride in both flavored and non- flavored extemporaneous preparations

The objective of this study was to evaluate the chemical stability of hydralazine hydrochloride 0.1% and 1% when prepared extemporaneously from commercially available hydralazine bulk powder. The oral solutions were prepared to contain preservatives, sweeteners, a humectant and diluting agents. They were prepared flavored and nonflavored and stored in duplicate glass and plastic bottles. Each of the flavored preparations was stored at 5 deg C, 25 deg C/60% relative humidity and 40 deg C/75% relative humdidity. Samples from the bottles of concentrations stored under these conditions were taken for a period of up to 92 days. Each of the nonflavored preparations was stored at 5 deg C. Samples from the bottles stored under these conditions were taken for a period of up to 72 days. Samples were taken from glass and plastic bottles on the designated sampling days for both flavored and nonflavored preparations, and the samples were analyzed for drug concentration using a stability-indicating high-pressure liquid chromatography analyical technique. Degradation occurred faster in the 0.1% oral solution than in the 1% solution at all the studied conditions. At 40 deg C, a considerable amount of drug loss was observed for both the 0.1 % and the 1% oral solutions for the flavored preparations. For both flavored and nonflavored preparations, the lowest studied temperature condition (5 deg C) appeared to be the most favorable for the preparations, with 93% or more of the initial potency retained by day 29.