On the dimorphism and the pressure-temperature state diagram of racemic m-nisoldipine, a dihydropyridine calcium ion antagonist.

The pressure-temperature phase diagram of the dimorphism of racemic m-nisoldipine is constructed using temperatures and enthalpies of fusion of forms A and B. At ordinary pressure, the transition from form B to form A is found to occur around 192K, which indicates that these polymorphs are enantiotropically related and that form A is stable at room temperature. Nevertheless, the phase relationship turns to be monotropic when pressures become greater than about 100MPa, which indicates that form B becomes the sole stable phase.

Effects of m-nisoldipine on the activity and mRNA expression of four CYP isozymes in rats.

1. For the first time, a systemic in vivo investigation was employed to evaluate the potential effects of m-nisoldipine on activities of rat cytochrome P450 enzymes (CYP1A2, CYP2C11, CYP2D1 and CYP3A1) by both cocktail probe drugs and the quantitative real-time reverse-transcription polymerase chain reaction (RT-qPCR). 2. m-Nisoldipine-treated and blank control groups were respectively administered m-nisoldipine at the dosage of 2.5, 5 and 12.5 mg/kg and CMC-Na solution for 15 days consecutively, then they were given the probe drugs of caffeine, diclofenac, dextromethorphan and midazolam (all probes were 5 mg/kg) by p.o. The blood samples were collected at different times for liquid chromatography coupled with mass spectrometry (LC-MS) analysis. The corresponding pharmacokinetic parameters were applied to evaluate the effects of m-nisoldipine on the four CYP isoforms in vivo. In addition, RT-qPCR was performed to determine the effects of m-nisoldipine on the mRNA expression of CYPs in rat liver. Results indicated that high dose and middle dose of m-nisoldipine showed significant effects on all four CYPs and CYP2C11, respectively. Moreover, for CYP2D1 and CYP1A2, there were no significant effects found at either low or middle dose of m-nisoldipine. 3. This study could provide not only experimental evidence for potential clinical application of m-nisoldipine but also a practical strategy for assessing CYP-mediated drug-drug interactions.

Investigating the in vitro stereoselective metabolism of m-nisoldipine enantiomers: characterization of metabolites and cytochrome P450 isoforms involved.

m-Nisoldipine, as a novel 1,4-dihydropyridine calcium ion antagonist, was presented as a couple of enantiomers [(-), (+)-m-nisoldipine]. In this report, the in vitro metabolism of m-nisoldipine enantiomers was investigated in rat liver microsomes (RLM) by the combination of two liquid chromatography mass spectrometric techniques for the first time. The metabolites were separated and assayed by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry and further identified by comparison of their mass and chromatographic behaviors with reference substances. A total of 18 metabolites of (-)-m-nisoldipine and 16 metabolites of (+)-m-nisoldipine were detected, respectively, which demonstrated that (+)-m-nisoldipine is more metabolically stable than (-)-m-nisoldipine. In addition, the identified metabolic pathways of m-nisoldipine enantiomers were involved in dehydrogenation, oxidation and ester hydrolysis. Afterwards, based on high-performance liquid chromatography coupled to triple quadrupole linear ion trap mass spectrometry, various selective cytochrome P450 (CYP) enzyme inhibitors were employed to evaluate CYP isoforms. The results indicated that the inhibitors of CYP1A1/2, CYP2B1/2, 2D and 2C11 had no obvious inhibitory effects, yet the inhibitor of CYP 3A had a significant inhibitory effect on metabolism of m-nisoldipine enantiomers. This showed that CYP 3A might primarily metabolize m-nisoldipine in RLM.

Study of in vitro metabolism of m-nisoldipine in human liver microsomes and recombinant cytochrome P450 enzymes by liquid chromatography-mass spectrometry.

This is a report about the investigation of the metabolic fate of m-nisoldipine in human liver microsomes and the recombinant cytochrome P450 enzymes by using LC-MS/MS. A sensitive and reliable LC-MS/MS method was developed to obtain a rapid and complete characterization of new metabolites and the metabolism pathways. The analytes were separated on a reversed phase C18 column with acetonitrile and 0.1% aqueous formic acid as the mobile phase. Tandem mass spectrometry with positive electrospray ionization was used to enable the structural characterization of the metabolites. A total of 10 metabolites were characterized with proposed structures in the incubation of human liver microsomes by comparing their retention times and spectral patterns with those of the parent drug. Dehydrogenation of the dihydropyridine core and reactions of side chains such as hydroxylation and hydrolysis of ester bonds were the major metabolic pathways. The specific cytochrome P450 (CYP) enzymes responsible for m-nisoldipine metabolites were identified using chemical inhibition and cDNA expressed CYP enzymes. The results indicated that CYP2C19 and CYP3A4 might play major roles in the metabolism of m-nisoldipine in human liver microsomes.

Influences of Polyethylene Glycol6000 on the Solubility of m-Nisoldipine / 医药导报

Objective To investigate the influences of polyethylene glycol on the solubility and in vitro dissolution of m-nisoldipine,which could provide guidance for chosing formulations of m-nisoldipine. Methods Solid dispersions of m-nisoldipine were prepared by solvent-melting method with polyethylene glycol6000 matrix. DSC and XRD spectroscopy were applied to identify the solid dispersions. The solubility and in vitro dissolution were detected by UV spectroscopy. Results The DSC and XRD map were different from the crude drug and their physical mixtures. The dissolution rates(13,15,17) were faster(35. 31%,38. 71%,41. 48%) than that of the crude drug(26. 80%),and the dissolution rates of the solid dispersions in the same ratio were higher than the physical mixtures. Conclusion DSC analysis indicated that eutectic compounds were produced by the m-nisoldipine and polyethylene glycol,in which polyethylene glycol6000 acts as a carrier. The solubility and in vitro dissolution of m-nisoldipine can be increased.

Studies on separation and pharmacokinetics of m-nisoldipine enantiomers in beagle dog plasma by LC/MS/MS.

A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric (LC/MS/MS) method was developed and validated for the separation and determination of m-nisoldipine enantiomers in beagle dog plasma. Samples were pretreated by a single-step protein precipitation with acetonitrile. After m-nisoldipine racemic administration to beagle dogs, samples of m-nisoldipine enantiomers in beagle dog plasma were separated and determined on a ULTRON ES-OVM column (150 × 4.6 mm, 5 µm) at 20°C with a mobile phase consisted of methanol-acetonitrile-ammonium acetate (pH 7.0; 2mM) (15:15:70, v/v/v) at a flow rate of 0.8 mL/min. Chromatograms were monitored at 237 nm, and the API 4000 triple quadrupole mass spectrometer was operated in multiple reaction monitoring (MRM) scan mode using ElectroSpray ionization (ESI) source. The good linearity (rs=0.9958 and rr=0.9983) were found in the range 0.25-20 ng/mL. The lower limit of quantification (LLOQ) obtained was 0.25 ng/mL (n=6). All the validation data, such as accuracy, precision, intra-day and inter-day repeatability, were within the required limits. The method was successfully applied to separation and pharmacokinetics of m-nisoldipine enantiomers in beagle dog plasma. The result of statistics analysis shows that there are no significant differences between R-(-)-m-nisoldipine and S-(+)-m-nisoldipine (p>0.05). The study provides necessary evidences for the research and new drug development of m-nisoldipine enantiomers.

Effect of m-nisoldipine on the Ca~(2+)/CaM/CaN signal pathway in 5-HT-induced proliferation of rat PASMCs / 药学学报

This study is to explore the activation of the Ca2+/CaM/CaN signal pathway in 5-HT-induced proliferation of rat pulmonary artery smooth muscle cells (PASMCs) and the inhibitory effect of m-nisoldipine (m-Nis) on this pathway. PASMCs were cultured with the explant technique. The proliferation of PASMCs was evaluated by MTT assay. Confocal microscopy was used to measure the change of [Ca2+]i. The mRNA expression of CaM and CaN was evaluated by RT-PCR and the activity of CaN was measured according to the instruction of kits. The results of MTT assay suggested that 5-HT (1 ?mol?L-1) significantly induced the proliferation of rat PASMCs (P

The effect of m-Nisoldipine on 5-HT-induced proliferation,migration of rat PASMCs and the mechanisms / 中国药理学通报

Aim To explore the effect of m-Nisoldipine(m-Nis) on 5-HT-induced proliferation,migration of rat PASMCs and to study the mechanisms.Methods PASMCs were cultured with the explant technique,and were divided into 6 groups:control group,5-HT(1 μmol·L~(-1)) group and m-Nis(10~(-5),10~(-6),10~(-7),10~(-8) mol·L~(-1))group.MTT assay was used to evaluate the proliferation of PASMCs,and transwell chambers were used to detect the migration of PASMCs.In addition,the expression of PCNA and the phosphorylation of ERK1/2 were evaluated by Western blot analysis.Results m-Nis inhibited the proliferation(P<0.05 or P<0.01)and migration(P<0.01)of rat PASMCs induced by 5-HT obviously.Similarly,Western blot analysis of PCNA indicated that the expression of PCNA was significantly higher in 5-HT group than that in control group(P<0.01).Whereas,in four m-Nis treated groups,the level of PCNA was markedly decreased(P<0.05 or P<0.01).Meanwhile,m-Nis 10~(-5),10~(-6) and 10~(-7) mol·L~(-1) pretreatment also reduced 5-HT-induced phosphorylation of ERK1/2 obviously(P<0.05 or P<0.01).Conclusion m-Nis inhibits 5-HT-induced proliferation and migration of rat PASMCs obviously,which may be related to the inhibition of PCNA expression and the blockage of ERK1/2/MAPK signal pathway.

Preparation of m-Nisoldipine Solid Dispersion / 中国药房

OBJECTIVE:To prepare m-nisoldipine solid dispersion from poorly-soluble m-nisoldipine so as to improve its solubility and dissolution rate in vitro. METHODS: Solid dispersions of m-nisoldipine were prepared by coprecipitation method with poloxamer as carrier; Differential scanning calorimetry (DSC) was used to determine the status of nimodipine in carrier. The solubility and the dissolution rate of the solid dispersion in vitro were studied. RESULTS: DSC analysis indicated that eutectic mixture was formed from m-nisoldipine and poloxamer. The solubility of m-nisoldipine and the its solid dispersions prepared from m-nisoldipine and poloxamer at different ratio (1∶3, 1∶5, 1∶7) were 0.89, 4.50, 15.35, and 23.03 mg?L-1, respectively, and their 120 min dissolution rates were 26.80%, 38.57%, 41.38%, and 45.92%, respectively. In the same ratio, the dissolution rates of the solid dispersions were higher than those of their physics mixtures. CONCLUSIONS: The solid dispersion of m-nisoldipine prepared with poloxamer as carrier can increase the solubility and dissolution rate in vitro.

EFFECTS OF M-NISOLDIPINE AND NISOLDIPINE ON THE HEMODYNAMICS AND REGIONAL BLOOD FLOW IN CONSCIOUS RABBITS / 中国药理学通报

m-Nisoldipine ( m-Nis ) , isobutyl methyl 1 , 4-dihydro - 2, 6-dimethyl-4-( 3-nitrophenyl )-3 , 5-pyridine dicarboxylate, is a new calcium antagonist. Its effects on hemodynamics and regional blood flow as well as the distribution of cardiac output were evaluated in comparison with Nis with radio-biomicrospheres in conscious rabbits. ( 1 ) m-Nis ( 1 ?g/kg ? min-1 ? 10 min, iv ) increased cardiac output and cardiac index significantly (P0.05) ; ( 2 ) m-Nis increased stroke volume and left ventricular systolic work ( per beat ) while Nis slightly increased the former and decreased the later, and these differences were statistically significant (P