OBJECTIVE To develop a specific and rapid HPLC method to determine Pseudoephedrine hydrochloride (PSE) in plasma and to investigate
the pharmacokinetics of compound
pseudoephedrine cetirizine sustained release tablets in dogs. METHODS The plasma samples were extracted by ether. Phenylalanine hydrochloride(Phen) was used as the internal standard. Lichrospher C18 column was used with a mobile phase of methanol-water( 11 :29) .RESULTS PSE, Phen and the impurities in plasma were separated efficiently. A good linearity over the range of 0.10 to 10.00 μmol · L-1 was achieved. The recovery, accuracy and precision of intra-day and inter-day were all qualified.The concentrations of PSE in dog plasma were measured at different time points after oral administration of compound pseudoephedrine cetirizine sustained release tablets (T) and regular tablets(C) .The main pharmacokinetic parameters were obtained as follows: t1/2(1) (4.66 ± 1.43)h, t1/2(c) (3.78 ± 1.91)h, tmax(T)(4.0± 1.4)h, t max(C)(2.3 ± 0.5)h, C max(T) (5.47 ±2.41)μmol·L-1, cmax(c)( 12.31 ±3.57)μmol·-1.CONCLUSION The sustained release PSE tablet released more slowly.Its t1/2 was extended, and its maximal concentration was decreased significantly.