Mandibular and parotid salivary excretion of procainamide and N-acetylprocainamide after intravenous administration of procainamide to rats

Abstract

Abstract Flow rate, protein level and pH of mandibular and parotid saliva samples in rats were almost stabilized 2h after induction of salivation with pilocarpine (9ṁ0 mg h−1 kg−1). Salivary excretion profiles of procainamide, 50 mg kg−1 i.v., and its metabolite N-acetylprocainamide (NAPA) were then investigated. Plasma and salivary procainamide levels declined bi-exponentially with time almost in parallel. Salivary procainamide levels (Y) from both types of gland were correlated with the plasma level (X) over a wide concentration range [Y = 0ṁ108X + 1ṁ96 (r = 0ṁ795) for mandibular and Y = 0ṁ917X (r = 0ṁ974) for parotid glands]. The mean saliva to plasma concentration ratio (S/P ratio) was significantly higher in parotid (0ṁ974 ± 0ṁ243) than in mandibular (0ṁ284 05119) saliva samples. Similar correlations and S/P ratios were observed for NAPA. Procainamide and NAPA mean S/P ratios for saliva from both glands were fairly consistent with the calculated value according to the pH-partition hypothesis.