Interaction of chlorpromazine, fluphenazine and trifluoperazine with ocular and synthetic melanin in vitro

The aim of this study was to examine in vitro the binding capacity of three phenothiazine derivatives--chlorpromazine, fluphenazine and trifluoperazine--causing adverse effects in the eye structures, to natural melanin isolated from pig eyes as well as to synthetic DOPA-melanin used as a model polymer. The amount of drug bound to melanin was determined by UV spectrophotometry. The analysis of results for the kinetics of drug-melanin complex formation showed that the amount of drug bound to melanin increases with increasing initial drug concentration and longer incubation time, attaining an equilibrium state after about 24 h. Binding parameters, i.e. the number of binding sites (n) and association constants (K), were determined on the basis of Scatchard plots. For neuroleptic-ocular melanin and neuroleptic-DOPA-melanin complexes two classes of independent binding sites were found, with association constants K1 approximately 10(4) and K2 approximately 10(2) M (-1) for chlorpromazine and fluphenazine complexes, and K1 approximately 10(5) and K2 approximately 10(3) M(-1) for trifluoperazine complexes. The numbers of strong (n1) and weak (n2) binding sites indicate lower affinity of the drugs examined to ocular melanin compared with DOPA-melanin. The ability of chlorpromazine, fluphenazine and trifluoperazine to interact with melanin, especially the ocular melanin, in vitro is discussed in relation to the ocular toxicity of these drugs in vivo.

Photodegradation and phototoxicity of thioridazine and chlorpromazine evaluated with chemical analysis and aquatic organisms

The photochemical behaviour of chlorpromazine (CPZ) and thioridazine (THR) incubated under VIS light and a UV-A lamp was investigated with a high-performance liquid chromatography photodiode array detector (HPLC-PAD) and two bioassays. VIS light caused the decrease of CPZ and THR to 25% and 34% of the initial level, respectively, while UV-A degraded the drugs almost totally. CPZ and THR were very toxic to the protozoan Spirostomum ambiguum (Spirotox) and anostracan crustacean Thamnocephalus platyurus (Thamnotoxkit F) with 24-h LC50 values of around 0.5 mg l(-1). In spite of the drastic decrease of the concentration of the drugs, the irradiated samples were toxic to the protozoan, especially when a sublethal end-point was taken into consideration. Contrary to the protozoan the crustacean was not sensitive to the products of photodegradation. Mass spectrometry analysis showed the presence of dimers and trimers of the CPZ and mono-, di-, and tri-oxygenated derivatives of THR. The presented data give a strong indication of the importance of the investigation of the environmental fate of drugs, especially those known to be phototoxic.

Simultaneous measurements of K+ and calcein release from liposomes and the determination of pore size formed in a membrane

The changes induced by biologically active substances in the permeability to K+ and calcein of liposomes composed of egg phosphatidylcholine and cholesterol were measured simultaneously in order to rapidly screen the sizes of pores formed in a membrane, using different sized markers. The substances examined in the present study were classified into three types based on differences in the rates at which K+ and calcein were released. The first type released only K+, and included gramicidin A. The second type predominantly released K+, preceding the release of calcein, and included amphotericin B and nystatin. The third type, including antimicrobial peptides, such as gramicidin S, alamethicin, and melittin, and several membrane-active drugs, like celecoxib (non-steroidal anti-inflammatory drug), 1-dodecylazacycloheptan-2-one (named azone; skin permeation enhancer), and chlorpromazine (tranquilizer), caused the release of K+ and calcein simultaneously. Thus, the sizes of pores formed in a liposomal membrane increased in the following order: types one, two, and three. We determined the size more precisely by conducting an osmotic protection experiment, measuring the release of calcein in the presence of osmotic protectants of different sizes. The radii of pores formed by the second type, amphotericin B and nystatin, were 0.36 - 0.46 nm, while the radii of pores formed by the third type were much larger, 0.63 - 0.67 nm or more. The permeability changes induced by substances of the third type are discussed in connection with a transient pore formed in a lipid packing mismatch taking place during the phase transition of dipalmitoylphosphatidylcholine liposomes.

The Singlet Oxygen Oxidation of Chlorpromazine and Some Phenothiazine Derivatives. Products and Reaction Mechanisms

A kinetic and product study of the reactions of chlorpromazine 1, N-methylphenothiazine 2, and N-ethylphenothiazine 3 with singlet oxygen was carried out in MeOH and MeCN. 1 undergoes exclusive side-chain cleavage, whereas the reactions of 2 and 3, in MeOH, afforded only the corresponding sulfoxides. A mechanism for the reaction of 1 is proposed where the first step involves an interaction between singlet oxygen and the side-chain dimethylamino nitrogen. This explains why no side-chain cleavage is observed for 2 and 3.

The drug binding site of human α1-acid glycoprotein: Insight from induced circular dichroism and electronic absorption spectra

Human alpha(1)-acid glycoprotein (AGP) is an important drug binding plasma protein which affects pharmacokinetical properties of various therapeutic agents. For the first time, interpretation of the induced circular dichroism (ICD) spectra of drug-AGP complexes is presented yielding valuable information on the protein binding environment. ICD spectra were obtained by novel ligands of which AGP induced optical activity have never been reported (primaquine, mefloquine, propranolol, terazosin, carbamazepine, rhodamine B) and by re-investigation of ICD spectra of protein-bound drugs published earlier (chlorpromazine, dipyridamole, prazosin). Spectroscopic features of the ICD and absorption bands of drugs combined with native AGP indicated chiral non-degenerate exciton coupling between the guest chromophore and the indole ring of an adjacent tryptophan (Trp) residue. Results of additional CD experiments performed by using recombinant AGP mutants showed no changes in the ligand binding ability of W122A in sharp contrast with the W25A which was unable to induce extrinsic CD signal with either ligand. Thus, these findings unequivocally prove that, likely via pi-pi stacking mechanism, Trp25 is essentially involved in the AGP binding of drugs studied here as well as of related compounds. Survey of the AGP binding data published in the literature support this conclusion. Our results provide a fast and efficient spectroscopic tool to determine the inclusion of ligand molecules into the beta-barrel cavity of AGP where the conserved Trp25 is located and might be useful in ligand-binding studies of other lipocalin proteins.

A versatile method for determining the molar ligand-membrane partition coefficient

A novel method for the quantitative assessment of the membrane partitioning of a ligand from the aqueous phase is described, demonstrated here with the thoroughly studied antipsychotic chlorpromazine (CPZ). More specifically, collisional quenching of the fluorescence of a pyrene labeled fluorescent lipid analog 1-palmitoyl-2[10-(pyren-1-yl)]decanoyl-sn-glycero-3-phosphocholine (PPDPC) by CPZ was utilized, using 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine and -serine (POPC and POPS) liposomes as model membranes. The molar partition coefficient is obtained from two series of titrations, one with constant [phospholipid] and increasing [drug] and the other with constant [drug] and varying total [phospholipid], the latter further comprising of large unilamellar vesicles (LUVs) of POPC/POPS/PPDPC at a constant concentration of 10 microM and indicated concentrations of POPC/POPS LUVs. Notably, the approach described is generic and can be employed in screening for the membrane partitioning of compounds, providing that a suitable fluorescence parameter can be incorporated into one population of liposomes utilized as model membranes.

Interactions of chlorpromazine with phospholipid monolayers: effects of the ionization state of the drug

Molecular dynamics simulations have been performed to investigate the interactions between chlorpromazine (CPZ) and Langmuir monolayers of the zwitterionic dipalmitoylphosphatidylcholine (DPPC) and the anionic dipalmitoylphosphatidylglycerol (DPPG). Simulations for a fixed surface density and different charge states - neutral and protonated CPZ - were able to capture important features of the CPZ-phospholipid monolayer interaction. Neutral CPZ is predominantly found in the hydrophobic tail region, whereas protonated CPZ is located at the lipid-water interface. Specific interactions (hydrogen bonds) between protonated CPZ and the lipid head groups were found for both zwitterionic and anionic monolayers. We computed lipid tail order parameters and investigated the effects of the drug upon tail ordering. We also computed electrostatic surface potentials and found qualitative good agreement with experimental results.

Effect of electrolytes on the cloud point of chlorpromazine hydrochloride solutions

Cloud point (CP) phenomenon occurring in amphiphilic drug chlorpromazine hydrochloride (CPZ) solutions with and without salts is reported herein. The CP of a 50mM CPZ solution (prepared in 10mM sodium phosphate, SP, buffer) was found to decrease with increasing pH, both in the absence as well as presence (50mM) of added salts (NaCl, NaBr, LiBr, KBr, tetra-n-butylammonium bromide). Whereas, at a fixed concentration of NaCl, the CP increased with increasing CPZ concentration, addition of increasing amounts of salts (NaF, NaCl, NaBr, LiCl, KCl) to 50 mM CPZ solution (at pH 6.7) caused continuous increase in CP. On the basis of these studies the binding-effect orders of counterions and co-ions have been deduced, respectively, as: Br(-) > Cl(-) > F(-) and Li+ >Na+ >K+. The similar trend of increasing CP with addition of increasing amounts of quaternary bromides (tetramethylammonium bromide, TMeAB; tetraethylammonium bromide, TEtAB; tetra-n-propylammonium bromide, TPrAB; tetra-n-butylammonium bromide, TBuAB; tetra-n-pentylammonium bromide, TPeAB) to 50 mM CPZ solutions (at pH 6.7) was found to be dependent upon the alkyl chain length of the particular salt. The overall behaviour has been discussed in terms of electrostatic interactions, micellar growth, and mixed micelle formation.

Thermodynamic and Infrared Analyses of the Interaction of Chlorpromazine with Phospholipid Monolayers

An investigation has been made of the interaction between chlorpromazine (CPZ) and monolayers of 1,2-dipalmitoyl-sn-3-glycerophosphatidylcholine (DPPC) and 1,2-dipalmitoyl-sn-3-glycero[phospho-rac-(1-glycerol)] (DPPG), both at the air/water interface and in transferred Langmuir-Blodgett films. The Gibbs free energy, DeltaG, and the compressibility modulus (C(S)(-1)), obtained from the surface pressure isotherms, indicated changes in the in-plane interactions of CPZ/DPPG mixed monolayers, with positive values of DeltaG. The arrangement of CPZ in the zwitterionic DPPC monolayers causes a weaker interaction in CPZ/DPPC mixed monolayers, with the DeltaG fluctuating around zero. IR measurements in transferred monolayers showed that CPZ did not affect the conformational order of the acyl chains, its effects being limited to the bands corresponding to the headgroups. Furthermore, since no shift was observed for the acyl chain bands, the phase transition induced by CPZ is not a liquid expanded (LE) to liquid condensed (LC) transition, as the latter is associated with chain ordering. Taken together, the IR and compressibility results demonstrate that the effect from CPZ cannot be correlated with temperature changes in the subphase for pure monolayers, in contrast to models proposed by other authors.

Bacterial efflux systems and efflux pumps inhibitors

It is now well established that bacterial resistance to antibiotics has become a serious problem of public health that concerns almost all antibacterial agents and that manifests in all fields of their application. Among the three main mechanisms involved in bacterial resistance (target modification, antibiotic inactivation or default of its accumulation within the cell), efflux pumps, responsible for the extrusion of the antibiotic outside the cell, have recently received a particular attention. Actually, these systems, classified into five families, can confer resistance to a specific class of antibiotics or to a large number of drugs, thus conferring a multi-drug resistance (MDR) phenotype to bacteria. To face this issue, it is urgent to find new molecules active against resistant bacteria. Among the strategies employed, the search for inhibitors of resistance mechanisms seems to be attractive because such molecules could restore antibiotic activity. In the case of efflux systems, efflux pump inhibitors (EPIs) are expected to block the pumps and such EPIs, if active against MDR pumps, would be of great interest. This review will focus on the families of bacterial efflux systems conferring drug resistance, and on the EPIs that have been identified to restore antibiotic activity.

Investigation of the electrochemical oxidation products of zotepine and their fragmentation using on-line electrochemistry/electrospray ionization mass spectrometry

When zotepine, an antipsychotic drug, was electrochemically oxidized using electrospray ionization mass spectrometry (ESI-MS) coupled with a microflow electrolytic cell, [M + 16 + H]+ (m/z 348), [M-H]+ (m/z 330) and [M-14 + H]+ (m/z 318) were observed as electrochemical oxidation product ions (M represents the zotepine molecule). Although a major fragment ion that was derived from the dimethyl aminoethyl moiety was observed only at m/z 72 in the collision-induced dissociation (CID) spectrum of zotepine, new fragments such as m/z 315 and 286 ions could be generated in the CID spectrum by combining electrochemical oxidation and CID. Since these fragments were relatively specific with high ion strength, it was thought that they would be useful for developing a sensitive LC-MS/MS assay. The S-oxide and N-demethylated products were detected by electrolysis assuring that a portion of P450 metabolites of zotepine could be mimicked by the electrochemistry/electrospray ionization mass spectrometry (EC/ESI-MS) system.

Molecular Dynamics Simulations of Neutral Chlorpromazine in Zwitterionic Phospholipid Monolayers

Molecular dynamics simulations have been performed to investigate the interactions between chlorpromazine (CPZ), a neuroleptic drug used in the treatment of psychiatric disorders, and dipalmitoylphosphatidylcholine (DPPC), a zwitterionic phospholipid, in Langmuir monolayers. The results from simulations carried out at different monolayer surface densities were able to capture important features of the CPZ-lipid interaction. We find that neutral (unprotonated) CPZ is preferentially located in the lipid tail region of the phospholipids, in little contact with the aqueous phase, and that the orientation of its rigid ring structure and tail conformation vary with lipid surface density. CPZ is found to promote ordering of the lipid tails for all surface densities because of a reduction in the effective surface area per lipid upon addition of the drug. Similar effects have been observed in previous studies of cholesterol in DPPC monolayers, in which lipid tails were seen to order around the solute. This feature, however, is quite distinct from what we observe for the most dense monolayer considered here (area per lipid of 50 A(2)), for which we find that CPZ promotes a local distortion of the lipid tails in its immediate vicinity and a concomitant ordering of lipid tails located further away from the solute. This view is further supported by the results obtained for an approximated nonlinear vibrational sum frequency generation susceptibility, which showed greater tail disorder close to CPZ.

Existence of lipid microdomains in bilayer of dipalmitoyl phosphatidylcholine (DPPC) and 1-stearoyl-2-docosahexenoyl phosphatidylserine (SDPS) and their perturbation by chlorpromazine : A 13C and 31P solid-state NMR study

The polyunsaturated fatty acid docosahexaenoic acid (DHA, 22:6, n-3) is found at a level of about 50% in the phospholipids of neuronal tissue membranes and appears to be crucial to human health. Dipalmitoyl phosphatidylcholine (DPPC, 16:0/16:0 PC) and the DHA containing 1-stearoyl-2-docosahexenoyl phosphatidylserine (SDPS) were used to make DPPC (60%)/SDPS (40%) bilayers with and without 10 mol% chlorpromazine (CPZ), a cationic, amphiphilic phenothiazine. Resonances that are present in 13C NMR spectrum of the DPPC (60%)/SDPS (40%) sample and that disappear in presence of 10% CPZ most probably are due to the special interface environment, e.g. the hydrophobic mismatch, at the interface of DPPC and SDPS microdomains in the DPPC/SDPS bilayer. In itself the appearance of resonances at novel chemical shift values is a clear demonstration of a unique chemical environment in the DPPC (60%)/SDPS (40%) bilayer. The findings of the study presented here suggest CPZ bound to the phosphate of SDPS will slow down and partially inhibit such a DHA acyl chain movement in the DPPC/SDPS bilayer. This would affect the area occupied by a SDPS molecule (in the bilayer) and probably the thickness of the bilayer where SDPS molecules reside as well. It is quite likely that such CPZ caused changes can affect the function of proteins embedded in the bilayer.

Chronic inhibition of cardiac Kir2.1 and HERG potassium channels by celastrol with dual effects on both ion conductivity and protein trafficking

A high percentage of drugs and drug candidates has been found to cause cardiotoxicity by reducing potassium conductance, more commonly known as QT prolongation. However, some compounds do not show direct block of ionic flow, suggesting that other mechanisms may also lead to reduction of potassium currents. Using the functional recovery after chemobleaching (FRAC) assay, we have examined a collection of drugs and drug-like compounds for potential perturbation of cardiac potassium channel trafficking. Here we report that a significant number of inhibitory compounds displayed effects on channel expression on the cell surface. Further investigation of celastrol (3-hydroxy-24-nor-2-oxo-1 (10),3,5,7-friedelatetraen-29-oic acid), a cell-permeable dienonephenolic triterpene compound, revealed its potent inhibitory activity on both Kir2.1 and hERG potassium channels, causal to QT prolongation. In addition to acute block of ion conduction, celastrol also alters the rate of ion channel transport and causes a reduction of channel density on the cell surface. In contrast, celastrol has no effects on trafficking of either CD4 or CD8 membrane proteins. Furthermore, the potency for reducing surface expression is approximately 5-10-fold more effective than that for either direct acute inhibition or reported cytoprotectivity via activation of the heat shock transcription factor 1. Because the reduction of potassium channel activity is a common form of druginduced cardiotoxicity, the potent inhibition of cell surface expression by celastrol underscores a need to evaluate drug candidates for their chronic effects on biogenesis of potassium channels. Our results suggest that chronic exposure to certain drugs may be an important aspect of acquired QT prolongation.

Chiral Ionic Liquid that Functions as Both Solvent and Chiral Selector for the Determination of Enantiomeric Compositions of Pharmaceutical Products

We have successfully synthesized both enantiomers of a novel chiral ionic liquid, (R)- and (S)-[(3-chloro-2-hydroxypropyl) trimethylammonium][bis((trifluoromethyl)sulfonyl)amide] ((R)- and (S)-[CHTA]+[Tf2N]-) in optically pure form by a simple ion exchange reaction from corresponding chloride salts that are commercially available. In addition to the ease of preparation, this chiral IL has relatively high thermal stability (up to 300 degrees C), is liquid at room temperature (glass transition temperature of -58.4 degrees C), and exhibits strong enantiomeric recognition. The high solubility power and strong enantiomeric recognition ability make it possible to use this chiral IL to solubilize an analyte and to induce diastereomeric interactions for the determination of enantiomeric purity. In fact, we have successfully developed a novel method based on the near-infrared technique with this chiral IL serving both as solvent and as a chiral selector for the determination of enantiomeric purity. Enantiomeric compositions of a variety of pharmaceutical products and amino acids with different shape, size, and functional groups can be sensitively (milligram concentration) and accurately (enantiomeric excess as low as 0.6%) determined by use of this method.

Effects of Inorganic Ions on the Binding of Triflupromazine and Chlorpromazine to Bovine Serum Albumin Studied by Spectrometric Methods

The effects of inorganic salts, NaCl, NaBr, NaI, Na2SO4, KCl, KBr, KI, on the binding constants (Ks) of psychotropic phenothiazine drugs, triflupromazine (TFZ) and chlorpromazine, to bovine serum albumin (BSA) were examined by using second-derivative spectrophotometry. All of the salts examined, with the exception of Na2SO4, decreased the K values significantly, depending on the concentration of the salt, e.g., the decrease in the K values of both drugs were about 40% for 0.1 M NaCl. The results obtained with Na2SO4 indicated that neither Na+ nor SO4(2-) had any affect on the binding of the phenothiazines to BSA. Based on the Na2SO4 results and the finding that the effect of each potassium salt on binding was quite similar to that of the corresponding sodium salt, the effects of these halogen salts can be considered to be derived from their anions, although the phenothiazines are positively charged at pH 7.4. The effectiveness of the anions was determined to occur in the following order: I->>Br->Cl-; these results coincided with the published order of the binding affinity of these anions to albumin. The 19F-NMR spectra of TFZ in the presence of each of these halogen salts revealed a concentration-dependent decrease in the intensity of the signal at 13.8 ppm that had previously been assigned to the TFZ bound to Site II. Consequently, the effects of these anions on the binding of positively charged phenothiazine drugs are thought to be local steric effects caused by the binding of these anions to Site II.

Importance of polyunsaturated acyl chains in chlorpromazine interaction with phosphatidylserines: a 13C and 31P solid-state NMR study

The polyunsaturated fatty acid docosahexaenoic acid (DHA, c22:6, n-3) is found at a level of about 50% in the phospholipids of neuronal tissue membranes and appears to be crucial to human health. Dipalmitoyl phosphatidylcholine (DPPC, 16:0/16:0 PC), 1-palmitoyl-2-oleoyl phosphatidylserine (POPS) and the DHA containing 1-stearaoyl-2-docosahexenoyl phosphatidylserine (SDPS) were used to make DPPC (60%)/POPS (29%)/SDPS (11%) bilayers with and without 10 mol% chlorpromazine (CPZ), a cationic, amphiphilic phenothiazine. The T1 relaxation measurements make it clear that the saturated acyl chains carbons (palmitic, stearic and most of the oleic chain) and the choline head group are not affected by CPZ addition. The observed increased signal intensity and T1-values of DHA indicate reduced mobility of C4 and C5 due to CPZ binding. 31P NMR spectra confirm that CPZ binding to the phosphatidylserines in the bilayer enhances phospholipid head group mobility.

Antitrypanosomal, Antileishmanial, and Antimalarial Activities of Quaternary Arylalkylammonium 2-Amino-4-Chlorophenyl Phenyl Sulfides, a New Class of Trypanothione Reductase Inhibitor, and of N-Acyl Derivatives of 2-Amino-4-Chlorophenyl Phenyl Sulfide

Quaternization of the nitrogen atom of 2-amino-4-chlorophenyl phenyl sulfide analogues of chlorpromazine improved inhibition approximately 40-fold (3',4'-dichlorobenzyl-[5-chloro-2-phenylsulfanyl-phenylamino)-propyl]-dimethylammonium chloride inhibited trypanothione reductase from Trypanosoma cruzi with a linear competitive Ki value of 1.7 +/- 0.2 microM). Molecular modelling explained docking orientations and energies by: (i) involvement of the Z-site hydrophobic pocket (roughly bounded by F396', P398', and L399'), (ii) ionic interactions for the cationic nitrogen with Glu-466' or -467'. A series of N-acyl-2-amino-4-chlorophenyl sulfides showed mixed inhibition (Ki, Ki' = 11.3-42.8 microM). The quaternized analogues of the 2-chlorophenyl phenyl sulfides had strong antitrypanosomal and antileishmanial activity in vitro against T. brucei rhodesiense STIB900, T. cruzi Tulahuan, and Leishmania donovani HU3. The N-acyl-2-amino-4-chlorophenyl sulfides were active against Plasmodium falciparum. The phenothiazine and diaryl sulfide quaternary compounds were also powerful antimalarials, providing a new structural framework for antimalarial design.

Binding of chemicals to melanins re-examined: adsorption of some drugs to the surface of melanin particles

This work presents a first attempt to study the interaction of some drugs with melanins, realistically considered as solid aggregates of primary particles. This situation appears similar to the adsorption of organic molecules onto the surface of colloidal absorbers, as active carbon, zeolites or titanium dioxide. We have applied some of the most popular theoretical models used in technological applications with the aim to give a more realistic picture of the melanin-drug interaction responsible for some observed side effects in vivo. Moreover, this approach can simplify the problem of the search of the physical parameters dominating the binding processes, by reducing the phenomenon to a simple physisorption/chemisorption, at least in a first approximation. We have studied the binding to melanin of gentamicin, methotrexate and chlorpromazine, molecules with different physico-chemical and structural characteristics. Our study demonstrates the possibility to fit experimental adsorption data with Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich equations. In such a way we obtain binding parameters useful to characterize the drug-surface interaction in terms of energy and of mean affinity.

Effects of chlorpromazine with and without UV irradiation on gene expression of HepG2 cells

Damage to DNA can trigger a variety of stress-related signals that alter the expression of genes associated with numerous biological pathways. In this study, we have used a cDNA microarray representing 1089 genes related to DNA damage and repair, cell cycle, transcription, metabolism and other toxicologically important cell functions to identify genes regulated in response to DNA damage in HepG2 cells induced by UV-activated chlorpromazine (CPZ). CPZ itself is not genotoxic but, upon UV irradiation with a non-genotoxic dose in the UVA range, it produces reactive free radical intermediates with DNA damaging properties. Genotoxicity in HepG2 cells was assessed concomitantly to gene expression profiling using the Comet assay. Kinetic studies were performed at a non-cytotoxic but clearly photogenotoxic concentration of CPZ (1.25 microg/ml) to characterize gene expression profiles at four different time points (3, 7, 15, 23 h) post short-term treatment. The results obtained from repeated experiments display a time-dependent expression pattern of up-regulated and repressed genes with distinct peaks in the number of differentially expressed genes at the 7 and 23 h time points. Most of the genes with altered expression belonged to the functional categories of cell cycle regulation and cell proliferation. A comparison with published expression profiles established in response to other genotoxic compounds showed low levels of concordance, which is most likely caused by the fact that extremely different testing conditions were used.

Effects of phosphatidylserine and phosphatidylethanolamine content on partitioning of triflupromazine and chlorpromazine between phosphatidylcholine-aminophospholipid bilayer vesicles and water studied by second-derivative spectrophotometry

To assess the affinity of psychotropic phenothiazine drugs, triflupromazine (TFZ) and chlorpromazine (CPZ), for the membranes of central nervous system and the other organs in the body, the partition coefficients (Kps) of these drugs to phosphatidylcholine (PC)-phosphatidylserine (PS) and PC-phosphatidylethanolamine (PE) small and large unilamellar vesicles (SUV, LUV) were examined by a second-derivative spectrophotometric method, since PS is abundantly contained in the membranes of the central nervous system and PE is distributed widely in the membranes of the organs in the body. Size and preparation methods of the vesicles did not affect the Kp values at each aminophospholipid content suggesting that the partition of the phenothiazine drugs was not affected by the structural differences in the vesicles such as their curvature or asymmetric distribution of the phospholipids between the outer and inner layers of the bilayer membranes. However, the Kp values of both drugs increased remarkably according to the PS content in the bilayer membranes, i.e., the Kp values for the vesicles of 30 mol% PS content were about 3 times of that for the vesicles of PC alone, while both Kp values slightly reduced with the increase in the content of PE in the bilayer membranes of PC-PE vesicles. The results indicate that both drugs have higher affinity for the PC-PS bilayer membranes than for the PC and PC-PE membranes, which can offer an evidence for the fact that TFZ and CPZ are predominantly distributed and accumulated in the brain and nerve cell membranes that contain PS abundantly.

Ion-pair complex-based solvent extraction combined with chemiluminescence determination of chlorpromazine hydrochloride with luminol in reverse micelles

A new chemiluminescence (CL) method is proposed for the determination of chlorpromazine hydrochloride, which is based on the dichloromethane solvent extraction of ion-pair complex of tetrachloroaurate(III) with chlorpromazine hydrochloride and luminol chemiluminescence detection in a reversed micellar medium formed by the cation surfactant cetyltrimethylammonium bromide in a dichloromethane-cyclohexane (1:1 V/V)-water (0.3 mol/L Na2CO3 buffer solution with the pH of 11.5). The ion-pair complex of tetrachloroaurate(III) with chlorpromazine hydrochloride produced an analytical chemiluminescence signal when it entered the reversed micellar water pool. In the optimum conditions, CL intensities are proportional to concentrations of the studied drug over the range 0.05 approximately 10 microg/mL with a detection limit (DL) of 6 ng/mL. The relative standard deviation (R.S.D.) is 2.6% for 1.25 microg/mL chlorpromazine hydrochloride (n = 11). R.S.D. (precision) of inter-day and intra-day is less than 6%, and accuracy of inter-day and intra-day is satisfactory. The method has been applied to the determination of studied drug in pharmaceutical preparations and biological fluids with satisfactory results.

Spectroelectrochemical determination of chlorpromazine hydrochloride by flow-injection analysis

An original, simple and sensitive flow-injection spectroelectroanalytical method for the determination of chlorpromazine in pure form or in pharmaceutical formulations is described. The method is based on the formation of a stable cationic radical by electro-oxidation in sulfuric acid medium (0.1 mol l(-1)), monitored in situ at lambda=524 nm. The determination of chlorpromazine hydrochloride in pure form or in pharmaceutical formulations was explored, considering the amperometric and the absorptiometric signal. The association of these two signals enhanced the selectivity of the analysis and proved decisive when other electroactive compounds or excipients like ascorbic acid were present in the formulation. The analytical parameters have been evaluated and the results obtained using standard additions are in agreement with the reference methods.

Compatibility of nitroglycerin, diazepam and chlorpromazine with a new multilayer material for infusion containers

The stability and compatibility of three drugs: nitroglycerin, diazepam and chlorpromazine, with a new multilayer infusion bag were studied. The study was carried out comparatively with PVC bags with which these drugs are incompatible. The drugs were diluted in 5% dextrose or in 0.9% sodium chloride isotonic solutions. Solutions were stored during 8 or 48 h with or without any protection against light. Remaining concentrations of drug were determined by high-performance liquid chromatography (HPLC) during the storage. The admixtures were also monitored for precipitation, color change and pH. Whatever the isotonic solution used, the loss of drugs is in discredit of the use of PVC bags for their storage. So, these three drugs would not be stored in PVC bags. In multilayer bags, no loss of drugs and no color change were detected throughout the storage period. pH values were stable during the same storage period. These three drugs were compatible with multilayer bags in all tested conditions for 8 or 48 h. The leaching of the plasticizer di-(2-ethylhexyl) phthalate (DEHP), that is incorporated into PVC to make the bags soft and pliable was not detected in the three drug solutions during storage period. Our study confirms that these three drugs are incompatible with PVC bags, on the contrary the new materiel tested was proved to be interesting for drug storage.