Table 2. Stability of 2 mg/mL amiloride nasal spray solution.

Stability Parameter Analyzed	0	3 hours	24 hours	7 days
% Assay of amiloridea	96.5 ± 0.3	96.6 ± 0.2	95.2 ± 0.1	98.2 ± 0.4
pHb	4.5 ± 0.2	4.5 ± 0.2	4.5 ± 0.3	4.5 ± 0.3
Viscosity (cP)c	0.9 ± 0.04	0.9 ± 0.02	0.9 ± 0.01	0.9 ± 0.01

^a Values represent mean ± S.D. after triplicate analysis of three samples obtained from three nasal sprays. The % assay values are calculated from a calibrated curve prepared from a standard solution of USP amiloride hydrochloride.

^bValues represent mean ± S.D. pH after triplicate analysis from three nasal sprays. The pH reported is the final pH of the nasal spray after addition of amiloride hydrochloride solution to water. No significant difference in pH was observed between samples at various time points based on results from ANOVA (p > 0.05).

^cValues represent mean ± S.D. after triplicate analysis from three nasal sprays. No significant difference in viscosity was observed between samples at various time points based on results from ANOVA (p > 0.05).