ABSTRACT
Irritative voiding symptoms, urinary urgency, frequency, nocturia, painful voiding, bladder discomfort or stranguria, are to the urinary tract much as a cough is to the pulmonary system, i.e., they are a nonspecific manifestation of multiple potential underlying causes. Urinary tract infections (UTIs) are usually associated with irritative voiding symptoms, such as painful urination (dysuria), urinary urgency and frequency. Anticholinergic drugs like flavoxate, oxybutynin provide beneficial symptomatic relief. However, they have associated adverse anticholinergic effects, such as dry mouth, which hinders patient compliance. Phenazopyridine hydrochloride acts as a topical analgesic on the mucosal lining of the urinary tract and thus relieves the irritative symptoms associated with UTI. It is compatible with antibiotics and relieves pain during the interval before the antibiotic begins to control the infection. It is well-tolerated as it lacks the anticholinergic side effects of other anticholinergics.
ABSTRACT
OBJECTIVE:To study pharmacokinetics of domestic and imported Phenazopyridine hydrochloride tables and bioavailability of domestic tablets, and to evaluate the bioequivalence of two kinds of tablets. METHODS: A randomized crossover design was performed in 18 healthy male volunteers. They received a single oral dose of domestic or imported tablets 200 mg. Plasma concentration of phenazopyridine hydrochloride was measured by HPLC. The pharmacokinetic parameters were calculated by 3p97 software and relative bioavailability was evaluated. RESULTS: The plasma concentration-time curves of domestic and imported tablets conformed to one-compartment model. Main pharmacokinetic parameters of domestic tablets vs. imported tablets were as follows: t1/2Ke(3.52?2.03) h vs. (3.18?1.85)h; tmax(0.76?0.33) h vs. (0.79?0.43)h; Cmax(76.41?70.15) ng?mL-1 vs. (75.49?70.37) ng?mL-1; AUC0～8(159.10?116.32) ng?h?mL-1 vs. (164.65?129.89) ng?h?mL-1; AUC0～∞(237.12?115.06) ng?h?mL-1 vs. (262.69?155.05) ng?h?mL-1. The relative bioavailability of domestic tablets was (96.63?14.05)% compared with imported tablet. There was no significant difference between the pharmacokinetic parameters of two formulations by variance analysis, t-test and 1-2? confidence interval method. CONCLUSION: The domestic and imported tablets are bioequivalent.