Influence of phenothiazine molecules on the interactions between positively charged poly-l-lysine and negatively charged DPPC/DPPG membranes.

Phenothiazines are very effective antipsychotic drugs, which also have anticancer and antimicrobial activities. Despite being used in human treatment, the molecular mechanism of the biological actions of these molecules is not yet understood in detail. The role of the interactions between phenothiazines and proteins or lipid membranes has been much discussed. Herein, fourier-transform infrared (FTIR) spectroscopic studies were used to investigate the effect of three phenothiazines: fluphenazine (FPh); chlorpromazine (ChP); and propionylpromazine (PP) on the structures of a positively charged poly-l-lysine (PLL) peptide, a negatively charged dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylglycerol (DPPC/DPPG) membrane, and on the mutual interactions between electrostatically associated PLL molecules and DPPC/DPPG membranes. Phenothiazine-induced alterations in the secondary structure of PLL, the conformational state (trans/gauche) of the hydrocarbon lipid chains, and the hydration of the DPPC/DPPG membrane interface were studied on the basis of amide I' vibrations, antisymmetric and symmetric stretching vibrations of the CH2 groups of the lipid hydrocarbon chains (νsCH2), and stretching vibrations of the lipid C=O groups (νC = O), respectively. It was shown that in the presence of negatively charged DPPC/DPPG membranes, the phenothiazines were able to modify the secondary structure of charged PLL molecules. Additionally, the effect of PLL on the structure of DPPC/DPPG membranes was also altered by the presence of the phenothiazine molecules.

Acepromazine pharmacokinetics: a forensic perspective.

Acepromazine (ACP) is a useful therapeutic drug, but is a prohibited substance in competition horses. The illicit use of ACP is difficult to detect due to its rapid metabolism, so this study investigated the ACP metabolite 2-(1-hydroxyethyl)promazine sulphoxide (HEPS) as a potential forensic marker. Acepromazine maleate, equivalent to 30mg of ACP, was given IV to 12 racing-bred geldings. Blood and urine were collected for 7days post-administration and analysed for ACP and HEPS by liquid chromatography-mass spectrometry (LC-MS). Acepromazine was quantifiable in plasma for up to 3h with little reaching the urine unmodified. Similar to previous studies, there was wide variation in the distribution and metabolism of ACP. The metabolite HEPS was quantifiable for up to 24h in plasma and 144h in urine. The metabolism of ACP to HEPS was fast and erratic, so the early phase of the HEPS emergence could not be modelled directly, but was assumed to be similar to the rate of disappearance of ACP. However, the relationship between peak plasma HEPS and the y-intercept of the kinetic model was strong (P=0.001, r(2)=0.72), allowing accurate determination of the formation pharmacokinetics of HEPS. Due to its rapid metabolism, testing of forensic samples for the parent drug is redundant with IV administration. The relatively long half-life of HEPS and its stable behaviour beyond the initial phase make it a valuable indicator of ACP use, and by determining the urine-to-plasma concentration ratios for HEPS, the approximate dose of ACP administration may be estimated.

Stability of the tranquilizer drug propionylpromazine hydrochloride in formulated products.

An analytical method to evaluate propionylpromazine hydrochloride (PPZHCl) in tranquilizer formulations was developed using high-performance liquid chromatography (HPLC). During analysis of aged quality-control samples, a previously unreported chromatographic response was observed at a shorter retention time than PPZHCl. Further investigation of formulations stored in trap tap devices at temperatures ranging from 5 to 40 degrees C during field trials at four different locations confirmed the degradation of the active ingredient. Further investigation using HPLC/tandem mass spectrometry revealed two to five degradates, with the major degradates being oxidation products of the active ingredient, PPZHCl. As PPZHCl formulations must be stable when stored at 5 to 40 degrees C for 6 to 12 months, reformulation with the anti-oxidant ascorbic acid was utilized to achieve the required PPZHCl stability.

Spectrophotometric determination of vanadium(V) in minerals, steels, soil and biological samples using phenothiazine derivatives.

Two simple, rapid and sensitive spectrophotometric methods have been proposed for the determination of vanadium(V) using butaperazine dimaleate (BPD) and propionyl promazine phosphate (PPP). These methods are based on the formation of red-colored radical cations on reaction with vanadium(V) in phosphoric acid medium, with their absorbance maxima at 513 nm. Beer's law is valid over the concentration range of 0.25-5.0 micrograms ml-1 and 0.2-4.0 micrograms ml-1, with Sandell's sensitivity values of 6.1 ng cm-2 and 6.0 ng cm-2 for BPD and PPP respectively. The proposed methods have been successfully applied to the analysis of vanadium steels, minerals, biological samples and soil samples.

A liquid chromatographic method for the simultaneous determination of promethazine and three of its metabolites in plasma using electrochemical and UV detectors.

A new assay method has been developed for the quantitation of promethazine (PMZ) with a sensitivity and reproducibility as good as any previously reported method. This method is also capable of quantitatively determining three metabolites of PMZ (monodemethylated, sulphoxidated, and monodemethylated sulphoxidated PMZ), which has not been previously described. The method uses high-performance liquid chromatography with amperometric and UV detection simultaneously and requires only one extraction step from serum with chloroform. The method uses trifluoperazine as the internal standard. The limit of detection level for PMZ is 1.0 ng/ml when a 0.2-mL specimen of plasma is assayed. A validation study is also conducted for evaluating the recovery, precision, linearity of response, sensitivity, and selectivity of the method.

Determination of propionylpromazine hydrochloride in formulation matrixes using reversed-phase ion-pair small bore liquid chromatography.

Propionylpromazine hydrochloride (PPZHCl) has been investigated for use with leghold traps to reduce the amount of self-inflicted trauma experienced by animals restrained by these traps. Three types of PPZHCl formulations made with Karo dark syrup, K-Y Jelly, and Vaseline were used in 2 types of tranquilizer trap devices (TTDs). A reversed-phase ion-pair liquid chromatography (LC) method using a small bore C18 column was used to: (1) determine the purity of the PPZHCl material used in these formulations, and (2) to determine the resulting PPZHCl content of each formulation. Analyte quantitation was done using UV absorption at 280 nm. Regression analysis of calibration standard solutions indicated a linear and directly proportional relationship between analyte response and PPZHCl concentration over the range evaluated. Recovery data from: (1) Vaseline formulations containing 38.8, 16.2, and 8.78% PPZHCl were 104, 92.9, and 90.2%, respectively, (2) Karo dark syrup formulations containing 26.5, 18.1, and 10.3% PPZHCl were 97.7, 99.3, and 106%, respectively, and (3) K-Y Jelly formulations containing 33.0, 23.5, and 13.4% PPZHCl were 100, 99.4, and 88.7%, respectively. The relative standard deviation (RSD) values from triplicate analysis of these formulations ranged from 0.7 to 6.7%. The PPZHCl content from 9 manufactured TTDs, 3 for each formulation type, were analyzed in triplicate and produced RSD values ranging from 0.7-6.8%. These results indicate that the formulation extraction presented could be used to evaluate the PPZHCl content in TTDs prior to field use. The use of a small bore LC column reduced the amount of solvents consumed and hazardous waste generated, compared to sample analysis that uses a more conventional analytical LC column.

A previously unidentified acepromazine metabolite in humans: implications for the measurement of acepromazine in blood.

High-performance liquid chromatography-diode-array detection results obtained during the investigation of two cases involving acepromazine prompted us to study the stability of the drug in blood. It was found that acepromazine can undergo in vitro conversion by human red blood cells to 2-(1-hydroxyethyl)promazine, a product that has been reported as a minor urinary metabolite in horse urine but not previously identified in humans. Further, our analytical findings in the two cases examined suggest that 2-(1-hydroxyethyl)promazine may be the major unconjugated metabolite of acepromazine in humans. These findings have important implications for the analytical toxicology of acepromazine.

Multi-residue analysis of tranquillizers in meat: confirmatory assays using mass spectrometry.

A rapid and sensitive multi-residue method was developed to attempt to confirm the presence of the beta-blocker carazolol and the tranquillizers acepromazine, azaperone, chlorpromazine, propionylpromazine and xylazine in pig muscle tissues. The procedure involves determination by liquid chromatography coupled with tandem mass spectrometry. The liquid chromatographic separation was performed on a Symmetry C18 column with gradient elution. A mixture of aqueous buffer, containing 0.01% m/v trifluoroacetic acid (pH 3.5), and acetonitrile at a flow rate of 0.4 ml min-1 was used as the mobile phase. The abundant parent ions [M+ H+] produced by positive electrospray ionisation were selected for collisional dissociation with argon. Fragment ions were recorded with daughter ion scan and multiple reaction monitoring. The analytes were identified unambiguously by assessing retention times and diagnostic ions in meat samples spiked from 50 micrograms kg-1 [maximum residue limit (MRL) for azaperone and azaperol] to 5 micrograms kg-1 (MRL for carazolol).

Promazine pharmacokinetics during concurrent treatment with tricyclic antidepressants.

The aim of the present study was to search for a possible effect of tricyclic antidepressants on the pharmacokinetics of promazine. Male Wistar rats received promazine and/or an antidepressant (amitriptyline, imipramine) at a dose of 10 mg/kg i.p. twice a day for two weeks. Amitriptyline increased the plasma concentrations of promazine and N-desmethylpromazine. The concentration of promazine sulfoxide was lowered after 30 min, but later it was raised after 6 and 12 h. The interaction was pronounced after 6 and 12 h when the concentration of promazine was 3 times as high, that of N-desmethylpromazine 25 times as high, and that of sulfoxide 22 times as high as those observed after administration of promazine alone. Similar results were obtained in the brain. Imipramine produced less distinct changes in promazine pharmacokinetics. It did not produce any significant changes in promazine concentration (a tendency to raise it after 30 min was observed) in plasma, but it significantly increased the concentration of N-desmethylpromazine and decreased that of promazine sulfoxide. Changes in the brain did not follow closely those in the plasma. In the brain, significant increases in the levels of promazine and its metabolites were observed after 6 and 12 h. In vitro studies with liver microsomes showed that chronic co-administration of the antidepressants did not significantly influence the rate of promazine demethylation and sulfoxidation. Instead, the Lineweaver-Burk's analysis showed that both amitriptyline and imipramine competitively inhibited the two metabolic pathways of the neuroleptic. The potency of imipramine to inhibit the promazine metabolism in vitro was lower than that of amitriptyline, which was in line with its weaker effect on the pharmacokinetics of promazine in vivo. The observed increase in the sum of concentrations of the measured compounds (promazine + metabolites) in the plasma suggests additional inhibition by amitriptyline of another, metabolic pathway of promazine (e.g. hydroxylation). It is concluded that amitriptyline and imipramine which interfere with the metabolism (and probably distribution) of promazine produce potent increases in the brain (in the case of amitriptyline also in the plasma) concentrations of the neuroleptic.

[The effect of combolen on the erythrocyte distribution in the dog]. / Die Wirkung von Combelen auf die Erythrozytenverteilung im Hund.

The effect of Combolen (3.9 mg/kg bw s.c.) on the distribution of erythrocytes in dogs was investigated. After application of Combolen, the hematocrit of the animals decreased exponentially within 1 h by 21%. The reversal of the reduction began from 2 h after the time of application, amounting to 4% within the first day and finishing by the fourth day. After injection of 51Cr-labelled erythrocytes, radioactivity in the circulation of Combolen-treated dogs decreased exponentially within 2 h by at least 30%. It was concluded that the dog's spleen, under physiological conditions, contains about 10% of the animal's blood. The time-courses of the decrease of hematocrit and radioactivity in the circulation were found to be very similar. In accordance with this observation, a high correlation (r = 0.97) between the level of radioactivity after injection of radio-labelled erythrocytes and the corresponding hematocrit values after application of Combolen was found. After application of erythrocytes, labelled with 99mTc, an extensive distribution from the circulation into the spleen was observed by scintigraphy. This process can be understood by using a closed-compartment model. An equation, based on this model, describes the observed time course of the hematocrit values, as well as the number of 51Cr-labelled erythrocytes, in Combolen-treated dog. Presumably, the observed effect of Combolen is the result of the relaxation of the smooth muscle cells in the trabeculae of the spleen, caused by central-nervous depression of sympathetic tone. Combolen seems to be a suitable tool in pre-clinical testing of a novel blood preserve with dog as a test animal. Its potent ability to eliminate erythrocytes from circulation is distinguishable from the sequestration of damaged red cells. Furthermore, its ability to prevent the spleen from uncontrolled hematocrit modulating actions in addition to its sedative effects is considered to be an invaluable advantage.

[Effect of phenothiazine derivative on adrenal cortex response of sheep to repeated emotional stress]. / Wplyw pochodnej fenotiazyny na reakcje kory nadnerczy owiec w czasie wielokrotnego stresu emocjonalnego.

The study was aimed at the evaluation of propiopromazine (Combelen, Bayer), a derivative of phenothiazine, as an agent lowering in sheep the response to stress. The stress of emotional origin was induced in sheep by the isolation from herd lasting 1 hour. The isolation experiments were repeated 6 times on the same group of sheep, first three isolations (1-3) in daily intervals and next three (4-6) in weekly intervals. Propiopromazine was administered before each isolation experiment. The reaction of sheep to the isolation stress was weaker after propiopromazine administration. This was suggested by smaller increase in blood serum cortisol and glucose levels when compared to sheep subjected to isolation but not receiving the drug. Such effect was especially conspicuous during the course of the first isolation experiment; during the next experiments the difference concerning the reaction to stress between the sheep isolated from the herd receiving and not receiving the drug was gradually diminishing. It was shown in addition that propiopromazine administration to the sheep not subjected to stress caused an increase in cortisol level by 125 per cent and that in glucose level by 35 per cent. These results suggest that propiopromazine administration protects the organism against the effects of emotional stress only partially. Moreover, the effect of its administration gradually weakens with repeating of the stress inducing experiment, and propiopromazine itself may act as a stress inducing factor. It seems therefore that the use of propiopromazine and similar compounds as anti-stress agents may be questionable.

The anti-proliferative properties of 4-benzylphenoxy ethanamine derivatives are mediated by the anti-estrogen binding site (ABS), whereas the anti-estrogenic effects of trifluopromazine are not.

We compared the anti-proliferative properties of 4-benzylphenoxy-N ethyl morpholine (morpho-BPE) and trifluopromazine (TFP) on both the human breast cancer cell lines, MCF7, and its tamoxifen-resistant variant RTx6. We found that the calmodulin antagonist trifluopromazine (TFP) which bound ABS weakly, inhibited MCF7 cell growth but did not follow the relationship observed for diphenylmethane derivatives between MCF7-inhibitory potencies and their Ki. Regarding the tamoxifen-resistant RTx6 cells, TFP but not morpho-BPE induced inhibition of the proliferation. Using a tritiated derivative of morpho-BPE, two distinct binding sites could be demonstrated. Indeed, a low affinity binding site was present in both cell lines whereas a high affinity binding site was mainly found in MCF7 cells although being in lower concentration (less than 10%) in RTx6 cells. Both tamoxifen and TFP displaced morpho-BPE from the two binding sites. The uptake and efflux of the tritiated drug were similar in the two cell lines. The drug did not appear to be metabolized. We concluded that TFP and morpho-BPE belong to distinct classes of molecules and that ABS mediates the anti-proliferative action of diphenylmethane derivatives but not the inhibitory effect of the calmodulin antagonist TFP.

Haemodynamic changes during sedation in ponies.

The cardiovascular changes induced by several sedatives were investigated in five ponies with a subcutaneously transposed carotid artery by means of cardiac output determinations (thermodilution technique), systemic and pulmonary artery pressure measurements (direct intravascular method) and arterial blood analysis (blood gases and packed cell volume). The cardiovascular depression (decrease in systemic blood pressure and cardiac output) was long lasting (greater than 90 min) after administration of propionylpromazine (0.08 mg/kg intravenous (i.v.)) together with promethazine (0.08 mg/kg i.v.). The phenothiazine-induced sedation was not optimal. alpha 2-Agonists (xylazine (0.60 mg/kg i.v.) and detomidine (20 micrograms/kg i.v.)) induced initial but transient cardiovascular effects with an increase in systemic blood pressure and a decrease in cardiac output for about 15 min. Second degree atrioventricular blocks and bradycardia were seen during this period. The cardiovascular depression was more pronounced during detomidine sedation. Atropine (0.01 mg/kg i.v.) induced a tachycardia with a decrease in stroke volume but did not alter the cardiac output or other cardiovascular parameters. It prevented the occurrence of the bradycardia and heart blocks normally induced by xylazine or detomidine. Atropine potentiated the initial hypertension induced by the alpha 2-agonistic sedatives (especially detomidine). The decrease in cardiac output induced by xylazine, and to a lesser extent by detomidine, was partially counteracted when atropine was given in advance. The atropine-xylazine combination seemed the best premedication protocol before general anaesthesia as it only resulted in minor and transient cardiovascular changes.

In vivo photodegradation of chlorpromazine.

The in vivo photodegradation of chlorpromazine (CPZ) in the skin was investigated after systemic administration of 3H-CPZ to shaven Wistar rats and exposure to UV-A. Promazine (PZ) and 2-hydroxy-promazine (2-OH-PZ) appeared to be formed in irradiated rats, but not in the skin of rats kept in the dark. This indicates that upon irradiation with UV-A the PZ-radical is formed which can be held responsible for the photobinding to eye and skin constituents as observed earlier [Schoonderwoerd and Beijersbergen von Henegouwen (1987) Photochem. Photobiol. 46, 501-505]. Chlorpromazine-sulfoxide (CPZSO) is a major metabolite of CPZ. Less CPZSO was found in the skin of irradiated rats compared to those kept in the dark. As this appeared not to be caused by photobinding or photodegradation of CPZSO it can be concluded that CPZSO is not a photoproduct of CPZ under these experimental conditions. This study shows that the in vivo photodegradation of CPZ proceeds via the promazinyl radical rather than via the radical cation.

Stability, human blood distribution and rat tissue localization of promazine and desmonomethylpromazine.

The stability in human blood and urine, partitioning into red blood cells and plasma protein binding of promazine and desmonomethylpromazine were investigated. Tissue localization was investigated in rats. Promazine and desmonomethylpromazine were stable in human plasma and urine for at least 64 days at -20 degrees. The percentage of promazine not bound to protein in plasma was 10.4 +/- 2.43 as estimated by equilibrium dialysis with correction for volume shift, and 11.6 +/- 0.43 per cent as estimated by ultracentrifugation. Data for the mean plasma/red blood cell concentration ratio and the red blood cell/plasma distribution coefficient for promazine were 1.19 +/- 0.13 and 8.21 +/- 0.40, respectively. There was no evidence of time-dependence in plasma/red blood cell partitioning. Ten rat organs and tissues were examined. The concentrations of promazine and desmonemethylpromazine were highest in lung. For promazine, the rank order of tissue localization was lung greater than liver greater than kidney greater than intestine greater than brain greater than spleen greater than red blood cell greater than voluntary muscle greater than plasma greater than stomach greater than heart. For desmonomethylpromazine, the order was reversed in the cases of spleen and brain and interchanged in the cases of stomach and muscle. The brain/plasma concentration ratios for promazine and desmonomethylpromazine in rat were 4.69 and 3.87, respectively.

Metabolism and pharmacokinetic studies of propionylpromazine in horses.

The propionylpromazine concentrations in plasma after intramuscular administration to horses were determined using gas chromatography with nitrogen-phosphorus detection. After hydrolysis by beta-glucuronidase/arylsulphatase, the parent drug and three metabolites were detected in urine. The metabolites were identified as 2-(1-hydroxypropyl)promazine, 2-(1-propenyl)promazine and 7-hydroxypropionylpromazine by gas chromatography-mass spectrometry. No N-demethylated or sulphoxidated metabolites of propionylpromazine were observed in the horse urine.

Clinical effects of azaperone-metomidate, as compared to propionylpromazine-xylazine-metomidate or xylazine-ketamine combinations in anaesthesia of dogs.

Eighteen dogs of Tanzanian breeds divided into three groups of 6 were anaesthetized using either azaperone-metomidate (2 mg/kg, i.m. and 10 mg/kg i.p., respectively), propionyl promazine-xylazine-metomidate (2 mg/kg i.m., 1 mg/kg i.m. and 10 mg/kg i.p., respectively), or xylazine-ketamine (1 mg/kg i.m. and 11 mg/kg i.m., respectively). The clinical effects on respiration rate, heart rate and body temperature were studied until recovery. Hypersensitivity to noise was associated with azaperone metomidate anaesthesia. The other combination produced a smooth and uneventful induction and recovery from anaesthesia. Muscle relaxation and analgesia were adequate in all groups. Duration of xylazine-ketamine anaesthesia was shortest (30 +/- 5 minutes) followed by azaperone metomidate (50 +/- 15 minutes) and the longest duration was with propionyl promazine-xylazine-ketamine (120 minutes). Azaperone and metomidate was associated with marked increases in cardiac and respiration rates and marked hypothermia, which persisted throughout. Minimal changes were observed in the other combinations. Azaperone-metomidate seems to be preferable due to the moderate period of anaesthesia adequate for most operations. However, all the three combinations offer a practical application because of the convenient route of administration.