ABSTRACT:

Triprolidine HCl is a propylamine antihistamine commonly used as an over the counter drug found in liquid and solid dosage form preparations. Many factors was found to affect the stability of Triprolidine HCl in liquid dosage form like temperature, water, pH, UV light, and some excipients.

Triprolidine HCl was found to be unstable in water and followed first order kinetics. UV light was found to affect aggressively the stability of Triprolidine HCl ,but its degradation at pH 2 is much slower than that at pH 8. The pH-rate profile for the degradation of Triprolidine HCl was found to exhibit a bell shape with base catalysis portion above pH 7.0 but this portion was not found in the presence of 60% Sucrose which lowered the degradation rate at pH above 8.0, but increased it at pH 5, 6, and 7 aggressively. Maximum stability of Triprolidine HCl was found to occur at acidic medium of pH less than 3.0.

Some excipients studied was found to stabilize Triprolidine HCl solution, like Sorbitol, Mannitol, Glycerin, and Aspartame due to water structure enhancement, others was found to have no effect on the stability of Triprolidine HCl like Sodium saccharine and Propyleneglycol, while others like Glucose and to a higher extent Polyethyleneglycol 400 were found to increase the degradation rate of Triprolidine HCl .

Sucrose at low concentration, below 5g% was found to stabilize Triprolidine HCl in water, while at concentration higher than 10%, it was found to increase the degradation rate. The rate of degradation of Triprolidine HCl in commercial grade Sucrose was much higher than that in analytical grade Sucrose due to the presence of some impurities.

b-Cyclodextrin was found to have little effect on the stability of Triprolidine HCl in water but no effect on that in the presence of Sucrose.

Generally any substance that may enhance water structure will improve the stability of Triprolidine HCl in water. in addition Triprolidine HCl has two nitrogen atoms that are subjected to be ionized or unionized, at pH conditions where these two atoms were found in the ionized form maximum stability of Triprolidine HCl was achieved.

For the analysis of the large amount of stability samples a rapid, stability indicating method was developed. The optimum stationary phase was octasilane 5 mm particle size diameter, and a mobile phase of Acetonitrile : 0.4% Ammonium acetate : Triethylamine(800:200:1), the pH was adjusted to pH 7.5 with Glacial acetic acid. Also Triprolidine HCl UV scan was found to shift under different pH conditions but the isosbestic point at the wavelength 270nm was found to have constant absorbance at different pH conditions, thus it was chosen to be the wavelength used to detect the elution of Triprolidine HCl from the HPLC system.