[Antihypertensive effects of repeated oral administration of cilnidipine, a novel calcium antagonist, in 2K1C renal hypertensive dogs]

Rationality Evaluation of Packaging Materials and Study on Impurity Profiling of Cilnidipine Preparations by HPLC-Q-TOF/MS

Background:

The rationality of cilnidipine tablets and capsules with four different pharmaceutical packaging materials was evaluated, and the structure of photodegradation impurities was analyzed by LC-Q-TOF.

Materials and Methods:

The impurity profiling of commercial cilnidipine tablets and capsules was analyzed by LC-Q-TOF for the further improvement of official monograph in pharmacopoeias and the source of the impurities was investigated. The contents of photodegradation impurities were analyzed by HPLC, and remarkable difference in the formation of the photodegradation impurities in cilnidipine tablets and capsules with four different pharmaceutical packaging materials was observed. The shading effect of the four packaging materials was investigated by UV-Vis spectrophotometer and a remarkable difference was detected, which might be responsible for the difference in the formation of photodegradation products. The structures of photodegradation products were further characterized by LC-Q-TOF MS/MS. Five impurities in commercial cilnidipine tablets and capsules were separated and identified based on the high resolution MS/MS data.

Results:

The obtained results revealed that the impurity III was derived from the ethanol solution of cilnidipine when it was exposed to light, and the impurity II was produced when the cilnidipine powder was exposed to light directly. The concentrations for 50% reduction of impurity II and impurity III on the Chinese hamster lung cells (CHL) with CellTiter-Glo method were studied and the results indicated that the cytotoxicity of impurity II and impurity III on CHL cells was larger than cytotoxicity of cilnidipine.

Conclusion:

On the basis of our study, we suggested that the pharmaceutical packaging materials of cilnidipine tablets should be modified.

V. SK, Goud Palusa SK. Isolation and characterization of novel degradation products in cilnidipine by LC-QTOF-MS/MS, LCMSn, 2D-NMR and FTIR

Comprehensive stress studies performed for cilnidipine established 3D structures for novel degradants CD1 and CD2, which may be useful for drug discovery activities.

Study of the structures of photodegradation impurities and pathways of photodegradation of cilnidipine by liquid chromatography/Q-Orbitrap mass spectrometry

RATIONALE

The structures of photodegradation impurities in cilnidipine were studied by liquid chromatography/Q-Orbitrap mass spectrometry (LC/Q-Orbitrap MS) for the further improvement of the official monographs in Pharmacopoeias. The complete fragmentation patterns of impurities were investigated to obtain their structural information. Two pathways of photodegradation of cilnidipine were also explored to clarify the source of impurities in cilnidipine.

METHODS

Chromatographic separation was performed on a Boston Group C18 column (250 mm × 4.6 mm, 5 μm). The mobile phase consisted of acetonitrile/H2 O at a ratio of 75:25 (v/v). In order to determine the m/z values of the molecular ions and formulas of all detected impurities, full scan LC/MS in both positive and negative ion modes was firstly performed using a Thermo LC system coupled with a Q-Orbitrap high-resolution mass spectrometer. LC/MS/MS analysis was also carried out on target compounds to obtain as much structural information as possible.

RESULTS

Five novel photodegradation impurities of cilnidipine were separated and identified based on the high-resolution MS/MS data. Impurity III was synthesized and its structure was confirmed by (1) H-NMR and (13) C-NMR data. Two photodegradation pathways to produce different photodegradation impurities were also revealed in this study.

CONCLUSIONS

Among those impurities, impurities II and III were the main impurities which existed in the cilnidipine available on the market. Impurity II (the Z-isomer) was mainly produced when cilnidipine powder was directly exposed to daylight while impurity III (containing a piperidine ring) was mainly produced when cilnidipine was exposed to daylight in an ethanolic solution. Copyright © 2016 John Wiley & Sons, Ltd.

INFLUENCE OF BASELINE VALUES ON LIPIDS, LIPOPROTEINS AND FIBRINOLYTIC PARAMETERS DURING TREATMENT OF HYPERTENSION WITH CILNIDIPINE

Sixteen adult hypertensive patients of both sexes, classified as having 'medium' (total lipid profile 240-300 mg dl(-1)), and 'high' (total lipid profile >300 mg dl(-1)) baseline values, underwent serum lipids, lipoproteins and plasma fibrinolytic parameters evaluations after 3 months of cilnidipine treatment. Patients with 'medium baseline values' did not have any change in lipids, lipoproteins and fibrinolytic parameters while patients with 'high baseline values' had beneficial lipid and lipoprotein changes [decreases in total cholesterol (TC), triglycerides (TG), very low density lipoprotein-cholesterol (VLDLC) and increases in high density lipoprotein-cholesterol (HDLC), and HDLC/TC ratio] after cilnidipine treatment. Changes in lipids were negatively associated with fibrinolysis for the patients with 'medium baseline values' and positively associated in patients with 'high baseline values' after cilnidipine treatment. Reduction in blood pressure was related to fibrinolysis and reduced risk of coronary heart disease in the patients with 'high baseline values' after cilnidipine therapy. These results show that during cilnidipine treatment, the baseline lipid profile levels of the patients may influence the lipid altering actions as well as the interaction between lipids and fibrinolysis. 2000 Academic Press@p$hr Copyright 2000 Academic Press.