RESUMO
OBJECTIVE To determine the contents of N-nitroso impurities in raw materials/formulations of propranolol， metoprolol， atenolol， esmolol and bisoprolol， and clarify the attention threshold. METHODS Ultra-high performance liquid chromatography-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry（UPLC-Q/Orbitrap HRMS）was adopted. An ACE Excel 3 C18-AR column was used for the separation and a mixture of 0.2% formic acid solution with 0.01 mol/L ammonium acetate and methanol was employed as the mobile phase by gradient elution， at a flow rate of 0.60 mL/min. The column temperature was set at 40 ℃ ， and the sample size was 5 μL. The heated electrospray ionization source was employed in the positive full mass spectra-selected ion monitoring mode. The contents of N-nitroso impurities in raw materials/formulations of 15 batches of β-blockers from 10 manufacturers were determined by this method. Discovery Studio software was applied to predict the toxicity of the impurities and estimate the attention threshold. RESULTS Among 5 kinds of β-blockers， the linear ranges of N-nitroso propranolol， N-nitroso metoprolol， N-nitroso atenolol， N-nitroso esmolol and N-nitroso bisoprolol were 1.01-503.38， 1.02-508.38， 0.97-483.63， 1.11-554.27 and 1.05-523.92 ng/mL， respectively （r＞0.999）. The limits of quantitation were 1.04， 0.25， 0.05， 0.55 and 1.05 ng/mL， and the limits of detection were 0.52， 0.08， 0.02， 0.17 and 0.52 ng/mL， respectively. RSDs of precision， reproducibility， recovery， stability and durability tests were all lower than 7.5% （n＝6 or n＝5）. Among the 15 batches of samples， except for 1 batch， N-nitroso propranolol （1.07-8.91 ng/mg）， N-nitroso metoprolol （1.43-3.37 ng/mg）， N-nitroso atenolol （1.33 ng/mg）， N-nitroso esmolol （0.19 ng/mg） and N-nitroso bisoprolol （1.27 ng/mg） were detected in all other batches. According to predictions， the above 5 impurities had varying degrees of reproductive toxicity， mutagenicity and carcinogenicity， with attention thresholds of 1.0， 0.4， 4.3， 0.2 and 46.7 ng/mg， respectively. CONCLUSIONS The established method is simple， rapid， sensitive and specific， the estimated attention thresholds are clear， which can be used for the control of N-nitroso impurities in various β-blockers.
RESUMO
OBJECTIVE:To study the in vitro dissolution of Enalapril maleate and folic acid tablet. METHODS:HPLC was performed on the column of Agilent HC-C18 with mobile phase A of acetonitrle-phosphate buffer solution(70:30,V/V) and mobile phase B of acetonitrle-phosphate buffer solution(5:95,V/V)(gradient elution) at a flow rate of 1.0 ml/min,detection wavelength was 215 nm,column temperature was 50 ℃,and volume injection was 80 μl. Media were water,hydrochloric acid solution(pH 1.2),phosphate buffer solution(pH 5.0)and phosphate buffer solution(pH 6.8),medium volume was 900 ml and rotation speed was 50 r/min. The dissolution behavior of enalapril maleate in Enalapril maleate and folic acid tablet in 4 media were studied and compared with the dissolution behavior in vitro in original preparation of Enalapril maleate tablet,meanwhile,the dissolution behar-ior of folic acid in Enalapril maleate and folic acid tablet in phosphate buffer solution(pH 5.0)were studied and compared with dis-solution data of folic acid preparation in Japanese Orange Book to evaluate the intrinsic quality. RESULTS:The linear range was 0.561-14.03μg/ml for enalapril maleate(r=0.999 9)and 0.043-1.085μg/ml for folic acid(r=0.999 9),respectively;RSDs of pre-cision and stability tests were lower than 2.0%;recoveries of enalapril maleate in 4 media were 100.63%-102.33%(RSD=0.72%, n=9),99.27%-100.44%(RSD=0.41%,n=9),99.71%-100.29%(RSD=0.15%,n=9)and 96.74%-99.19%(RSD=0.79%,n=9),respectively. Recoveries of folic acid were 100.18%-101.63%(RSD=0.48%,n=9),97.73%-101.81%(RSD=1.32%,n=9),99.60%-102.24%(RSD=0.74%,n=9)and 100.00%-102.76%(RSD=0.90%,n=9),respectively. In 15 min,the dissolution of enalapril maleate of 2 preparations in 4 dissolution media were more than 85%;dissolution speed of folic acid in Enalapril male-ate and folic acid tablet was faster than that in folic acid preparation in phosphate buffer solution(pH 5.0). CONCLUSIONS:The method is suitable to determine the dissolution of Enalapril maleate and folic acid tablet;the in vitro dissolution curve of enalapril maleate in Enalapril maleate and folic acid tablet is similar to Renitec,and the in vitro dissolution of folic acid is better than folic acid preparation.