Comparison of high-performance thin layer chromatography/UV-densitometry and UV-derivative spectrophotometry for the determination of trimetazidine in pharmaceutical formulations.

New methods for assaying trimetazidine dihydrochloride on the basis of thin layer chromatography and spectrophotometry are proposed and compared in the paper. In HPTLC/UV-densitometry, separation is achieved by using a mobile phase composed of ammonia-methanol (30:70, V/V) on silica gel HPTLC plates F254. Quantification using a non-linear calibration curve is accomplished by densito-metric detection at 230 nm. Derivative spectrophotometric determination of trimetazidine dihydrochloride is carried out from the fourth derivative of the absorbance at 233 nm in peak-zero mode. Statistical comparison led to the conclusion that there is no significant difference between the two studied methods and, moreover, that they demonstrate satisfactory accuracy and precision for routine applications.

Mucoadhesive elementary osmotic pump tablets of trimetazidine for controlled drug delivery and reduced variability in oral bioavailability.

The objectives of this work was preparation and evaluation of the mucoadhesive elementary osmotic pump tablets of trimetazidine hydrochloride to achieve desired controlled release action and augmentation of oral drug absorption. The drug-loaded core tablets were prepared employing the suitable tableting excipients and coated with polymeric blend of ethyl cellulose and hydroxypropyl methylethylcellulose E5 (4:1). The prepared tablets were characterized for various quality control tests and in vitro drug release. Evaluation of drug release kinetics through model fitting suggested the Fickian mechanism of drug release, which was regulated by osmosis and diffusion as the predominant mechanism. Evaluation of mucoadhesion property using texture analyzer suggested good mucoadhesion potential of the developed osmotic systems. Solid state characterization using Fourier-transform infrared spectroscopy, differential scanning calorimetry and powder X-ray diffraction spectroscopy confirmed the absence of any physiochemical incompatibilities between drug and excipients. Scanning electron microscopy analysis showed the smooth surface appearance of the coated tablets with intact polymeric membrane without any fracture. In vivo pharmacokinetic studies in rabbits revealed 3.01-fold enhancement in the oral bioavailability vis-à-vis the marketed formulation (Vastarel MR®). These studies successfully demonstrate the bioavailability enhancement potential of the mucoadhesive elementary osmotic pumps as novel therapeutic systems for other drugs too.

Ultrasonic microdialysis coupled with capillary electrophoresis electrochemiluminescence study the interaction between trimetazidine dihydrochloride and human serum albumin.

The paper describes a homemade ultrasonic microdialysis device coupled with capillary electrophoresis electrochemiluminescence (CE-ECL) for studying the interaction between human serum albumin (HSA) and trimetazidine dihydrochloride (TMZ). The time required for equilibrium by ultrasonic microdialysis was 45min, which was far less than that by traditional dialysis (240min). It took 80min to achieve the required combination equilibrium by normal incubation and only 20min by ultrasonic. Compared with traditional dialysis, the use of ultrasonic microdialysis simplified experimental procedures, shortened experimental time and saved consumption of sample. A simple, sensitive and selective determination of TMZ was developed using CE-ECL and the parameters that affected ECL intensity were optimized. Under the optimized conditions, the linear range of TMZ was from 0.075 to 80µmol/L (r(2)=0.9974). The detection limit was 26nmol/L with RSD of 2.8%. The number of binding sites and binding constant were 1.54 and 15.17L/mol, respectively.

Synthesis of oxidized glycerol monooleate-chitosan polymer and its hydrogel formation for sustained release of trimetazidine hydrochloride.

In this paper, a lipid material glycerol monooleate was used as the starting material to synthesize the oxidized glycerol monooleate (OGMO). OGMO was subsequently linked to chitosan (CS) via imine bonds (-C=N-) to obtain a new chitosan-based polymer (OGMO-CS), which can form hydrogels rapidly in aqueous media. Scanning electron microscopy, swelling behavior studies and degradation kinetics studies were performed to demonstrate the effect of this synthetic modification on the hydrogels formation of chitosan network and in vitro drug release. The effects of OGMO-CS type, dry hydrogels percentage, release media and drug loading on the sustained release of the model drug trimetazidine hydrochloride were evaluated. The release profiles of the hydrogels could be described by the Peppas-Sahlin mechanism, a combination of Fickian diffusion and Case-II relaxation. Based on the fact that numerous pharmaceutical lipids are available, the present study may pave the way for other lipids to be employed as modifiers of chitosan for more innovative chitosan derivatives with versatile properties and pharmaceutical applications.

Elucidation of release characteristics of highly soluble drug trimetazidine hydrochloride from chitosan-carrageenan matrix tablets.

The aim of this study was to better understand the underlying drug release characteristics from matrix tablets based on the combination of chitosan (CS) and different types of carrageenans [kappa (κ)-CG, iota (ι)-CG, and lambda (λ)-CG]. Highly soluble trimetazidine hydrochloride (TH) was used as a model drug. First, characteristics of drug release from different formulations were investigated, and then in situ complexation capacity of CG with TH and CS was studied by differential scanning calorimetry and Fourier transform infrared spectroscopy. Erosion and swelling of matrix were also characterized to better understand the drug-release mechanisms. Effects of pH and ionic strength on drug release were also studied. It was found that not only ι-CG and λ-CG could reduce the burst release of TH by the effect of TH-CG interaction, CS-ι-CG- and CS-λ-CG-based polyelectrolyte film could further modify the controlled-release behavior, but not CS-κ-CG. High pH and high ionic strength resulted in faster drug release from CS-κ-CG- and CS-ι-CG-based matrix, but drug release from CS-λ-CG-based matrix was less sensitive to pH and ionic strength. In conclusion, CS-λ-CG-based matrix tablets are quite promising as controlled-release drug carrier based on multiple mechanisms.

Drug release characteristics from chitosan-alginate matrix tablets based on the theory of self-assembled film.

The aim of this study was to better understand the underlying drug release characteristics from chitosan-alginate matrix tablets containing different types of drugs. Theophylline, paracetamol, metformin hydrochloride and trimetazidine hydrochloride were used as model drugs exhibiting significantly different solubilities (12, 16, 346 and >1000 mg/ml at 37 °C in water). A novel concept raised was that drugs were released from chitosan-alginate matrix tablets based on the theory of a self-assembled film-controlled release system. The film was only formed on the surface of tablets in gastrointestinal environment and originated from chitosan-alginate polyelectrolyte complex, confirmed by differential scanning calorimetry characterization. The formed film could decrease the rate of polymer swelling to a degree, also greatly limit the erosion of tablets. Drugs were all released through diffusion in the hydrated matrix and polymer relaxation, irrespective of the drug solubility. The effects of polymer level and initial drug loading on release depended on drug properties. Drug release was influenced by the change of pH. In contrast, the impact of ionic strength of the release medium within the physiological range was negligible. Importantly, hydrodynamic conditions showed a key factor determining the superiority of the self-assembled film in controlling drug release compared with conventional matrix tablets. The new insight into chitosan-alginate matrix tablets can help to broaden the application of this type of dosage forms.

Hollow fiber-based liquid membrane microextraction combined with high-performance liquid chromatography for extraction and determination of trimetazidine in human plasma.

A hollow fiber-based liquid phase microextraction strategy combined with high-performance liquid chromatography was evaluated for the quantitative determination of trimetazidine in human plasma. Trimetazidine was extracted from a 2.1 mL basified plasma sample (donor phase) into the organic solvent (n-octanol) impregnated in the pores of a hollow fiber and then extracted into an acidic solution (acceptor phase) inside the lumen of the hollow fiber. The result showed that transport of drugs from alkaline sample solution into 0.5 m HCl occurred efficiently when 25 µL of 250 mm sodium 1-octanesulfonate was added into the donor phase. Several parameters influencing the efficiency of the method, such as the nature of organic solvent used to impregnate the membrane, compositions of donor phase and acceptor phase, type and concentration of carrier, extraction time, stirring rate and salt concentration, were investigated and optimized. Under the optimal conditions, the calibration curves were obtained in the range of 5-200 ng/mL with reasonable linearity (r > 0.9980). The method was successfully applied to determine the concentration of trimetazidine in human plasma.

Floating tablet of trimetazidine dihydrochloride: an approach for extended release with zero-order kinetics.

Trimetazidine dihydrochloride is an effective anti-anginal agent; however, it is freely soluble in water and suffers from a relatively short half-life. To solve this encumbrance, it is a prospective candidate for fabricating trimetazidine extended-release formulations. Trimetazidine extended-release floating tablets were prepared using different hydrophilic matrix forming polymers including HPMC 4000 cps, carbopol 971P, polycarbophil, and guar gum. The tablets were fabricated by dry coating technique. In vitro evaluation of the prepared tablets was performed by the determination of the hardness, friability, content uniformity, and weight variation. The floating lag time and floating duration were also evaluated. Release profile of the prepared tablets was performed and analyzed. Furthermore, a stability study of the floating tablets was carried out at three different temperatures over 12 weeks. Finally, in vivo bioavailability study was done on human volunteers. All tablet formulas achieved < 0.5 min of floating lag time, more than 12 h of floating duration, and extended t (1/2). The drug release in all formulas followed zero-order kinetics. T4 and T8 tablets contained the least polymer concentration and complied with the dissolution requirements for controlled-release dosage forms. These two formulas were selected for further stability studies. T8 exhibited longer expiration date and was chosen for in vivo studies. T8 floating tablets showed an improvement in the drug bioavailability compared to immediate-release tablets (Vastrel® 20 mg).

Development and validation of a simple and sensitive liquid chromatography-tandem mass spectrometry method for quantifying trimetazidine in human plasma.

1. A simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for quantifying trimetazidine in human plasma was developed and validated. Sample preparation was based on deproteinating with acetonitrile. 2. Chromatography was performed on a C18 analytical column (5 mum; 150 x 2.1 mm i.d.) and the retention times for trimetazidine and cetirizine (used as the internal standard) were 1.8 and 3.0 min, respectively. The ionization was optimized using an electrospray ionization source and enhanced selectivity was achieved using tandem mass spectrometry. The calibration curve ranged from 0.1 to 200 ng/mL. The inter-day precision, accuracy and the relative standard deviation (RSD) were all < 15%. The analyte was shown to be stable over the time-scale of the entire procedure. 3. The robustness of the method was demonstrated by the good reproducibility of the results obtained during the analysis of clinical samples.

Attenuation of myocardial ischemia-reperfusion injury by trimetazidine derivatives functionalized with antioxidant properties.

Trimetazidine (TMZ), an anti-ischemic metabolic drug, is used to treat chest pain (angina pectoris). We hypothesized that derivatives of TMZ with antioxidant functions may improve the cardiac dysfunction caused by ischemia-reperfusion (I/R) above that observed with TMZ alone. Isolated rat hearts perfused with Krebs-Henseleit buffer according to the Langendorff method were subjected to 30 min of global ischemia followed by 45 min of reperfusion. Trimetazidine, TMZ-NH (TMZ modified with a pyrroline moiety), or TMZ-PhiNH (TMZ-NH with a phenyl substitute) were infused (50 microM) for 1 min before the onset of ischemia. Untreated (control) hearts at the end of 45 min of reperfusion showed a significant decrease in the recovery of coronary flow (42%), left ventricular-developed pressure (22%), and rate-pressure product (25%) compared with preischemic baseline values. The I/R hearts also showed markedly increased lactate dehydrogenase and creatine kinase activities in the coronary effluent, significant myocardial infarction (46% of risk area), and activation of Akt, extracellular signal-regulated kinase, and p38 mitogen-activated protein kinase. Pretreatment of hearts with TMZ-NH or TMZ-PhiNH significantly enhanced the recovery of heart function and decreased infarct size. The I/R-induced activation of Akt was further enhanced by TMZ-PhiNH. The present study demonstrated that TMZ-NH and TMZ-PhiNH significantly protected hearts against I/R-mediated cardiac dysfunction and injury. The protective effect of the TMZ derivatives could be due to the combined effects of antioxidant and anti-ischemic activities as well as enhanced pro-survival Akt activity.

Chronic angina: new medical options for treatment.

As the US population ages, the pool of patients with coronary artery disease and stable angina is projected to grow. Conventional approaches with mechanical and pharmacological therapies have made inroads toward curbing this trend, reducing the risk of future myocardial infarction and cardiac death. However, the potential benefits of currently available antianginal medications are limited by reduced work capacity, orthostasis, and important drug-drug interactions. A new approach is represented by the piperazine derivatives trimetazidine (TMZ) and ranolazine (RNZ). TMZ acts to partially inhibit fatty acid oxidation, thus shifting myocardial energy metabolism to a lower oxygen-consuming state. A total of 16 randomized trials have been completed with TMZ. In the US market, 6 trials have been completed with RNZ. RNZ has been separately classified as a late sodium channel inhibitor, which reverses action potential prolongation, suppresses early after-depolarizations, and terminates resultant ventricular tachycardia. Though it has some of the same fatty acid oxidation properties as TMZ, this is not considered its primary mechanism of action. This paper reviews medical approaches to chronic stable angina and highlights RNZ as an important advance for patients and clinicians in the US market.

Quantitative determination of some pharmaceutical piperazine derivatives through complexation with iron(III) chloride.

A simple, accurate and sensitive spectrophotometric method has been developed for the determination of three pharmaceutical piperazine derivatives, namely ketoconazole (KC), trimetazidine hydrochloride (TMH) and piribedil (PD). This method is based on the formation of yellow orange complexes between iron(III) chloride and the investigated drugs. The optimum reaction conditions, spectral characteristics, conditional stability constants and composition of the water soluble complexes have been established. The method permits the determination of KC, TMH and PD over a concentration range 1-15, 1-12 and 1-12 microg ml(-1), respectively. Sandell sensitivity is found to be 0.016, 0.013 and 0.013 microg cm(-2) for KC, TMH and PD, respectively. The method was sensitive, simple, reproducible and accurate within +/-1.5%. The method is applicable to the assay of the three drugs under investigation in different dosage forms and the results are in good agreement with those obtained by the official methods (USP and JP).

S15176 and S16950 interaction with Cyclosporin A antiproliferative effect on cultured human lymphocytes.

S15176 and S16950 are trimetazidine derivatives that antagonize more strongly than the parent drug mitochondrial toxicity, which leads to cellular hypoxia and nephrotoxicity in kidneys experimentally exposed to cyclosporin A. We have investigated whether every derivative might interact or not with the inhibitory effect of Cyclosporin A on the proliferation of cultured human lymphocytes. S15176 significantly increased the antilymphoproliferative effect of Cyclosporin A, whereas S15176 by itself neither displayed any antilymphoproliferative effect, nor did it induce any apoptotic process in cultured human lymphocytes. The effect of S16950 was not significant.

The pH-partition profile of the anti-ischemic drug trimetazidine may explain its reduction of intracellular acidosis.

PURPOSE: The anti-ischemic drug trimetazidine (TMZ) acts by a combination of molecular mechanisms which begin to be understood. Thus, it acts in the micromolar range to significantly reduce intracellular acidification during ischemia. To search for a possible physicochemical explanation of this phenomenon, we investigated the transfer mechanisms of the various electrical forms of this dibasic drug. METHODS: The transfer characteristics of TMZ were studied by electrochemistry at the water/1,2-dichloroethane interface. Cyclic voltammetry was used to measure the formal transfer potentials of singly and doubly protonated forms of TMZ (noted TH+ and TH(2)2+, respectively) as a function of aqueous pH, and the partition coefficient of neutral TMZ (log P(T)) was measured by two-phase titration. RESULTS: log P(T) was measured to be 1.04 +/- 0.06, and the acid-base dissociation constants in water were deduced to be pK(w)a1 = 4.54 +/- .02 and pK(w)a2 = 9.14 +/- 0.02. The partition coefficients of TH+ and TH(2)2+ were found to be respectively log P0'TH+ = -3.78 +/- 0.16 and log P0'TH(2)2+ = -9.84 +/- 0.30, which agrees well with the charge being delocalized on two nitrogen atoms in TH+. The pH-partition profile of TMZ was then established in the form of its ionic partition diagram, which showed that the affinity of the ions for the organic phase is pH-dependent and strongly increased by the interfacial potential. CONCLUSIONS: This behavior suggests a physicochemical mechanism whereby efflux of protonated TMZ out of an acidified cell is facilitated, in effect exporting protons to extracellular space.

Structure-property relationships of trimetazidine derivatives and model compounds as potential antioxidants.

Twenty-five compounds (trimetazidine derivatives and other compounds, mostly having a free phenolic group) were examined for their radical scavenging and antioxidant properties. Their reaction with DPPH (2,2-diphenyl-1-picrylhydrazyl) as a measure of radical scavenging capacity was assessed by two parameters, namely EC50 (the concentration of antioxidant decreasing DPPH by 50%), and log Z, a kinetic parameter proposed here and derived from initial second-order rate constants and antioxidant/DPPH ratios. Antioxidant activities were determined by the inhibition of lipid peroxidation and albumin oxidation. The most active compounds were derivatives having a trolox or hydroquinone moiety. Physicochemical and structural properties were determined by molecular modeling as lipophilicity (virtual log P calculations) and H-Surf (solvent-accessible surface of hydroxyl hydrogen) and by quantum mechanical calculations (deltaH(ox) = oxidation enthalpy; deltaH(abs) = enthalpy of hydrogen abstraction). QSAR models were derived to identify molecular mechanisms responsible for the reactivity toward the DPPH radical and for the inhibition of lipid peroxidation. A useful prediction of antioxidant capacity could be achieved from calculated molecular properties and the kinetic parameter developed here.

Effects of trimetazidine on lipid peroxidation and phosphorus metabolites during cold storage and reperfusion of isolated perfused rat kidneys.

This study was undertaken to evaluate the effect of trimetazidine (TMZ) during cold storage (CS) and the consequence during normothermic reperfusion in an isolated perfused rat kidney model (IPK). IPK was used to assess the rate of perfusion flow, the ratio of ATP to inorganic phosphate (ATP/Pi) as a reflection of the energetic status during reperfusion, intracellular pH (pHi), tissue water content and malondialdehyde (MDA) tissue levels in four different preservation solutions after 48-hr preservation at 4 degreesC and 2-hr reperfusion at 37.5 degreesC: EuroCollins (EC), University of Wisconsin (UW), EC plus TMZ (10(-)6 M) (EC + TMZ) and UW plus TMZ (10(-)6 M) (UW + TMZ). When TMZ was added to the preservation solutions, perfusion flow rate (PFR) was significantly improved during reperfusion. Tissue water content, which reflected tissue edema, was significantly lower in TMZ groups than in groups without TMZ during both CS and reperfusion conditions. In TMZ groups, ATP/Pi ratio was also significantly improved during CS and reperfusion. In addition, TMZ lowered the pHi both during preservation and after reperfusion. MDA renal tissue level significantly decreased with TMZ both during the preservation period and after reperfusion. These overall results strongly suggested that TMZ contributes to renal protection from cold ischemia-reperfusion injury in this IPK model, especially when TMZ was added to UW solution and during prolonged hypothermic ischemia.