Study On Quality Control, Stability And Bioequivalence Of Ramipril Capsules

Background and Objective: Ramipril, 2-[N-[(S)-1-(ethoxycarbonyl)-3-phenylpropyl)]-L-alanyl]-(1S, 3S, 5S)-2-azabicyclo(3-3-0)octane carboxylicacid, was developed by Hoechst in German and gone on the market in Frenchin 1999. It known as a prodrug of angiotensin converting enzyme in-hibitor(ACEI), could be metabolized to ramiprilat after abosorbed and inhibitangiotensin-converting enzyme and then block the conversion of angiotensinⅠto angiotensinⅡ. Ramipril is often used in regulation of hypertensionand treatment of congestive heart failure.The quality standard of ramipril capsules was established after studyingthe description, identification, related substances, dissolution and assayof ramipril. Ramipril capsules stability study could provide the evidencefor storage condition and period of validity. And the study ofpharmacokinetics and relative bioavailability of ramipril capsule alsocould be as the reference to clinical use.Methods: In this study, ramipril was identified specifically using theretention time of principal peak. The dissolution, related substance andcontent assay were detected by HPLC method. Chromatographic condition:Alltima C18 column (250×4.6mm, Sum) was employed as analytical column,the mobile phase consisted of acetonitrile-2% sodium perchlorate solution (Dissolve 2.0 g of sodium perchlorate in a mixture of 0.5 ml of triethylamineand 1000 ml of water;adjust to pH 2.9 with phosphoric acid )(35:65);thedetection wavelength was set at 210 nm and the flow rate of mobile phasewas 1.0ml/min. The apparatus of methodⅢwas used for dissolution test withwater as the dissolution medium. The rotational speed of the paddle was setat 100 rpm. The solution was withdrawed for 30 minutes, then filtered,determinated and calculated the dissolution. The stability test of theproduct was included the influencing factors test, accelerate test andlong-term stability test.For studying the bioequivalence of ramipril capsules, we establishedan LC/MS/MS method to determine the medication and its active metaboliteramiprilat in the human plasma. Enalapril was used as the internal standard.Ramipril and Ramiprilat was chromatographed by using a Waters Atlantis C18column.The mobile phase consisted of metanol-0.1% formic acidsolution(75:25).Electrospray ionization(ESI) source was applied andoperated in the positivion mode. Selected reaction monitoring(SRM) mode withthe transitions of m/z 417.3-234.3, m/z 389.3-206.2 and m/z 377.3-234.2was used to quantify ramipril, ramiprilat and the internal standard,respectively.Results: An excellent separation was achieved for ramipril and itsrelated substances. The assay was validated over the concentration range of20～200mg/L(r>0.9998). The precision intra-day and inter-day was 0. 4% and 0.9%respectively. The accumulation dissolution percentages were more than 90%at 30 min, There were no difference among the dissolution of three batches.All results from stability test showed that ramipril was not stable to lightand heat, but was stable to humidity.The main pharmacokinetic parameters of ramipril were as follow: t_max(0.60±0.17) and (0.63±0.25) h , C_max(40.11±14.48) and (41.78±13.18) ng/ml,t_1/2(2.75±1.36)and(2.28±1.28)h, AUC_0-12(42.09±11.22) and(41.81±12.89)ng ? h/ml for test and reference, respectively. The mainpharmacokinetic parameters of ramiprilat were as follow: t_max(2.70±0.47)and (2.60±0.60) h , C_max(42.02±12.53) and (41.80±14.65) ng/ral, t_1/2(17.99±6.28) and (18.51±5.81 ) h, AUC_0-72 ( 310.65±91.42 ) and(310.21±102.74) ng ? h/ml for test and reference, respectively. Therelative bioavailability of ramipril was (101.47±16.02) %, and ramiprilatwas (101.09±15.28)%.Conclusion: The standard established could be used as a quality controlof ramipril capsules and the ramipril capsules tested were found to bebioequivalent to reference preparation.