Escitalopram in the treatment of major depressive disorder: A meta-analysis

ABSTRACT

Objective: To assess the relative antidepressant efficacy of escitalopram and comparator antidepressants.

Research design and methods: A meta-analysis was performed using studies in major depressive disorder (MDD) comparing escitalopram with active controls, including selective serotonin reuptake inhibitors [SSRIs] (citalopram, fluoxetine, paroxetine, sertraline) and serotonin/noradrenaline reuptake inhibitors [SNRIs] (venlafaxine, duloxetine). Adult patients had to meet DSM-IV criteria for MDD.

Main outcome measures: The primary outcome measure was the treatment difference in Montgomery–Åsberg Depression Rating Scale (MADRS) total score at week?8. Secondary outcome measures were response and remission (MADRS total score ≤?12) rates.

Results: Individual patient data (N?=?4549) from 16 randomized controlled trials were included in the analyses (escitalopram n?=?2272, SSRIs n?=?1750, SNRIs n?=?527). Escitalopram was significantly more effective than comparators in overall treatment effect, with an estimated mean treatment difference of 1.1?points on the MADRS (p?<?0.0001), and in responder (63.7?vs. 58.3%, p?<?0.0001) and remitter (53.1?vs. 49.4%, p?<?0.0059) analyses. Escitalopram was significantly superior to SSRIs, with an estimated difference in response of 62.1?vs. 58.4% and remission of 51.6?vs. 49.0%. In comparison to SNRIs, the estimated difference in response was 68.3?vs. 59.0% (p?=?0.0007) and for remission the difference was 57.8?vs. 50.5% (p?=?0.0088). These results were similar for severely depressed patients (baseline MADRS ≥?30). Sensitivity analyses were performed with data from articles reporting Hamilton Rating Scale for Depression (HAMD) scores. The 8-week withdrawal rate due to adverse events was 5.4% for escitalopram and 7.9% for the comparators (p?<?0.01). This difference was accounted for by statistically significant higher attrition rates in the SNRI comparisons. This work may be limited by the clinical methodology underlying meta-analytic studies, in particular, the exclusion of trials that fail to meet predetermined criteria for inclusion.

Conclusions: In this meta-analysis, superior efficacy of escitalopram compared to SSRIs and SNRIs was confirmed, although the superiority over SSRIs was largely explained by differences between escitalopram and citalopram.     

In vivo imaging of serotonin transporter occupancy by means of SPECT and [123I]ADAM in healthy subjects administered different doses of escitalopram or citalopram

Background Escitalopram is a dual serotonin reuptake inhibitor (SSRI) approved for the treatment of depression and anxiety disorders. It is the S-enantiomer of citalopram, and is responsible for the serotonin reuptake activity, and thus for its pharmacological effects. Previous studies pointed out that clinically efficacious doses of other SSRIs produce an occupancy of the serotonin reuptake transporter (SERT) of about 80% or more. The novel radioligand [¹²³I]ADAM and single photon emission computer tomography (SPECT) were used to measure midbrain SERT occupancies for different doses of escitalopram and citalopram.Methods Twenty-five healthy subjects received a single dose of escitalopram [5 mg (n=5), 10 mg (n=5), and 20 mg (n=5)] or citalopram [(10 mg (n=5) and 20 mg (n=5)]. Midbrain SERT binding was measured with [¹²³I]ADAM and SPECT on two study days, once without study drug and once 6 h after single dose administration of the study drug. The ratio of midbrain-cerebellum/cerebellum was the outcome measure (V3”) for specific binding to SERT in midbrain. Subsequently, SERT occupancy levels were calculated using the untreated baseline level for each subject. An E _max model was used to describe the relationship between S-citalopram concentrations and SERT occupancy values. Additionally, four subjects received placebo to determine test–retest variability.Results Single doses of 5, 10, or 20 mg escitalopram led to a mean SERT occupancy of 60±6, 64±6, and 75±5%, respectively. SERT occupancies for subjects treated with single doses of 10 and 20 mg citalopram were 65±10 and 70±6%, respectively. A statistically significant difference was found between SERT occupancies after application of 10 and 20 mg escitalopram, but not for 10 and 20 mg citalopram. There was no statistically significant difference between the SERT occupancies of either 10 mg citalopram or 10 mg escitalopram, or between 20 mg citalopram and 20 mg escitalopram. E _max was slightly higher after administration of citalopram (84%) than escitalopram (79%). In the test–retest study, a mean SERT “occupancy” of 4% was found after administration of placebo, the intraclass correlation coefficient was 0.92, and the repeatability coefficient was 0.25.Conclusion SPECT and [¹²³I]ADAM were used to investigate SERT occupancies after single doses of escitalopram or citalopram. The test–retest study revealed good reproducibility of SERT quantification. Similar SERT occupancies were found after administration of equal doses (in respect to mg) of escitalopram and citalopram, giving indirect evidence for a fractional blockade of SERT by the inactive R-citalopram.     

Cardiovascular effects elicited by milonine, a new 8,14-dihydromorphinandienone alkaloid

Abstract: The mechanisms underlying the cardiovascular responses evoked by milonine (i.v.), an alkaloid, were investigated in rats. In normotensive rats, milonine injections produced hypotension and tachycardia, which were attenuated after N^w‐nitro‐l ‐arginine methyl esther (l ‐NAME; 20 mg/kg, i.v.). In phenylephrine (10 μM), pre‐contracted mesenteric artery rings, milonine (10^?10 M to 3 × 10^?4 M) caused a concentration‐dependent relaxation (EC₅₀ = 1.1 × 10^?6 M, E_max = 100 ± 0.0%) and this effect was rightward shifted after either removal of the vascular endothelium (EC₅₀ = 1.6 × 10^?5, p < 0.001), or after l ‐NAME 100 μM (EC₅₀ = 6.2 × 10^?5, p < 0.001), hydroxocobalamin 30 μM (EC₅₀ = 1.1 × 10^?4, p < 0.001) or ODQ 10 μM (EC₅₀ = 1.9 × 10^?4p < 0.001). In addition, in rabbit aortic endothelial cells, milonine increased NO₃^? levels. The relaxant effect induced by milonine was attenuated in the presence of KCl (20 mM), a modulator efflux K⁺ (EC₅₀ = 1.2 × 10^?5, p < 0.001), or different potassium channel blockers such as glibenclamide (10 μM) (EC₅₀ = 6.3 × 10^?5, p < 0.001), TEA (1 mM) (EC₅₀ = 2.3 × 10^?5 M, n = 6) or Charybdotoxin (0.2 μM) plus apamin (0.2 μM) (EC₅₀ = 3.9 × 10^?4 M, n = 7). In addition, pre‐contraction with high extracellular potassium concentration prevented milonine‐induced vasorelaxation (EC₅₀ = 1.0 × 10^?4, p < 0.001). Milonine also reduced CaCl₂‐induced contraction in Ca²⁺‐free solution containing KCl (60 mM). In conclusion, using combined functional and biochemical approaches, we demonstrated that the hypotensive and vasorelaxant effects produced by milonine are, at least in part, mediated by the endothelium, likely via nitric oxide release, activation of nitric oxide‐cGMP pathway and opening of K⁺ channels.     

Proapoptotic and chemosensitizing effects of selective serotonin reuptake inhibitors on T cell lymphoma/leukemia (Jurkat) in vitro

While selective serotonin reuptake inhibitors (SSRIs) are commonly used for psychiatric indications, evidence implies them to possess anti-cancerous properties as well. We evaluated such in vitro effects in malignant T cells (Jurkat), finding that exposure to high concentrations of sertraline (IC₅₀ = 9.5 µM) or paroxetine (IC₅₀ = 18 µM) yielded a considerable reduction in cellular viability, exceeding equimolar doses of the chemotherapeutics vincristine and cyclophosphamide (P < 0.015). The cytotoxic effects included both inhibition of proliferation and induction of apoptosis, demonstrated by decreased [³H] thymidine incorporation and increased activity of the caspase-3 enzyme, as well as a decrease in the expression of the Bcl-2 proto-oncogene. No effect on c-Jun or ERK was observed, rendering the complete mechanism yet to be fully elucidated. When combined with chemotherapy, sertraline (7.5 µM) markedly enhanced the effects of both vincristine and doxorubicin, suggesting SSRI antidepressants as potential new chemosensitizers in chemotherapeutic regimens, pending further in vivo research.     

Absorption mechanism of oxymatrine in cultured Madin–Darby canine kidney cell monolayers

Context Oxymatrine (OMT) is beneficial to human health by exerting various biological effects. Objective To investigate the absorption mechanism of OMT and discover absorption enhancers using Madin–Darby canine kidney (MDCK) cell monolayers.

Materials and methods Concentration effects on the transport of OMT were measured in the range of 1.0?×?10^?5–1.0?×?10^?3 M in 2?h. Then, the effect of time, direction, temperature and pH on the transport of OMT at 10^?4 M was studied. Moreover, P_app of OMT was determined in the absence/presence of cyclosporine and surfactants at 100?μM to further confirm the relative transport mechanism.

Results The P_{app AP→BL} ranged from (3.040?±?0.23)?×?10^?6 to (3.697?±?0.19)?×?10^?6?cm/s as the concentration varied from 10^?5 to 10^?3 M. OMT showed similar P_app at 4 and 37?°C (p?>?0.05). Increasing the apical pH 7.4 and 8.0 resulted in P_app versus pH 5.0 (p?<?0.01). Furthermore, in the presence of cyclosporine and surfactants including sodium citrate, sodium dodecyl sulphate (SDS) and deoxysodium cholate, P_app was (0.318?±?0.033)?×?10^?5, (0.464?±?0.048)?×?10^?5, (0.897?±?0.115)?×?10^?5 and (1.341?±?0.122)?×?10^?5?cm/s, respectively. In the presence of surfactants, P_app significantly increased up to 1.5–4.3-fold (p?<?0.05).

Discussion and conclusion OMT transport across MDCK cell monolayers was by passive diffusion. Sodium citrate, SDS and deoxysodium cholate serve as excellent absorption enhancers which are useful for the related research improving the oral bioavailability of OMT.     

Effect of nitroxyalkyl derivatives of fullerenylproline on the activity of CA<Superscript>3+</Superscript>-ATPase of sarcoplasmic reticulum

The effect of nitroxyalkyl derivatives of fullerenylproline methyl ester on the enzymatic activity of Ca²⁺-ATPase of sarcoplasmic reticulum (SR) has been studied. It is shown that hybrid derivatives of C₆₀ fullerene are capable of inhibiting the activity of Ca²⁺-ATPase of SR. The mononitrate inhibits the hydrolytic activity of the enzyme with K _i = 1.92 × 10⁻⁶ M; active Ca²⁺ transport, with K _i = 3.79 × 10⁻⁶ M. The dinitrate inhibits ATP hydrolysis with K _i = 2.38 × 10⁻⁸ M; Ca²⁺ transport, with K _i  = 3.08 × 10⁻⁸ M. Fullerenylproline methyl ester does not affect the enzymatic activity of Ca²⁺-ATPase. Based on these data it is possible to predict the possible fields of application for hybrid fullerene derivatives as potential drugs.     

Contractile effects of endothelins on isolated ampullar segment of human oviduct in luteal phase of menstrual cycle

Endothelin-1 induces contractions of human oviduct ampullar segment in follicular phase of menstrual cycle, acting on ET_A receptors. The aim of our study was to investigate effects of endothelin-1, endothelin-2 and endothelin-3 on isolated ampullar segment of human oviducts, taken from the patients in luteal phase of menstrual cycle. Fallopian tubes were taken from 20 female patients (one tube from each patient) during abdominal hysterectomy with adnexectomy, due to extensive uterine fibroids. The oviduct ampulla was mounted in an organ bath longitudinally, and the tension of the isolated preparation was recorded with the isometric transducer. Endothelin-1 produced concentration-dependent tonic contraction of the isolated ampullar segment (EC₅₀ = 6.80 ± 1.2 × 10^?10 M), and concentration-dependent inhibition of its rhythmic contractions (EC₅₀ = 7.86 ± 2.3 × 10^?10 M). Endothelin-2 produced concentration-dependent tonic contraction of the isolated ampullar segment (EC₅₀ = 4.56 ± 0.3 × 10^?10 M), without affecting its rhythmic contractions. Endothelin-3 did not affect either tone or rhythmic contractions of the isolated preparations. Selective antagonist for ET_A receptor subtype, BQ 123, produced inhibition of endothelin-1 effects on both tone (pA₂ = 9.50) and spontaneous rhythmic contractions (pA₂ = 10.73), while selective antagonist for ET_B receptor subtype, BQ 788, produced only inhibition of endothelin-1 effects on tone (pA₂ = 9.61), while the effect of endothelin-1 on spontaneous rhythmic contractions remained unaffected. The results of our study suggest that in the luteal phase both ET_A and ET_B receptors regulate tone, and only ET_A receptors regulate rhythmic activity of human oviduct's ampullar segment.     

The role of the pharmacist in mental health: An investigation of the impact of pharmacist-led interventions on psychotropic medication adherence in patients with diabetes

ObjectiveTo evaluate the impact of targeted telepharmacist mental health adherence interventions for patients with type 2 diabetes.MethodsThis retrospective review involved the analysis of a telepharmacist-led mental health intervention. The subjects included: patients aged 18 years or more with type 2 diabetes, enrolled in an adherence service and who had been prescribed psychotropics. Psychotropic medication adherence was measured using the proportion of days covered (PDC) 6 months before and after the telepharmacist-led medication intervention.ResultsA total of 8167 patients (67% women), with a mean age of 63 ± 11 years, were included in the study. Most alerts for psychotropics were for selective serotonin reuptake inhibitors (SSRIs) (53%, n = 4334), selective norepinephrine reuptake inhibitors (SNRIs) (22%, n = 1775), second-generation antipsychotics (11%, n = 909), and bupropion (10%, n = 782). Alerts with the greatest volume of PDCs (above 85%) at postintervention follow up included SSRIs (51%, n = 2228), SNRIs (50%, n = 884), and second-generation antipsychotics (47%, n = 424). Before the alert, the mean PDC was 66% ± 12% across all medications studied. Post intervention, the mean PDC rose to 79% ± 19. A paired t-test revealed statistically significant improvement in adherence overall, with the greatest change observed in these alert groups: SSRIs (P < 0.001), alpha-2 antagonist (P < 0.001), SNRIs (P < 0.001), and bupropion (P < 0.001).ConclusionThis retrospective review showed that pharmacist-led targeted, adherence interventions greatly improved psychotropic medication adherence in adult patients with type 2 diabetes. Future work is warranted to investigate the impact on type 2 diabetes medication adherence and health markers (e.g., HbA1c values) in larger and more diverse populations of patients with comorbid type 2 diabetes and a mental health condition.     

A toxicity and hazard assessment of fourteen pharmaceuticals to Xenopus laevis larvae

The toxicity of fourteen widely used human pharmaceuticals was determined using the Frog Embryo Teratogenesis Assay–Xenopus (FETAX). Stage 9 Xenopus blastulae were exposed for 96 h to single concentrations of commonly prescribed selective serotonin reuptake inhibitors (SSRIs), statin blood lipid regulators, non-steroidal anti-inflammatories, antibiotics, a stimulant, and an anti-epileptic. Toxicity, teratogenicity, minimum concentration to inhibit growth, and types and severity of associated malformations were determined. EC₁₀s ranged from 3.0 mg/l to >100 mg/l and LC₁₀s ranged from 3.6 mg/l to >100 mg/l. Toxicity varied between and within compound class of pharmaceutical. The fluoroquinolones, stimulants, anti-epileptics, and antibiotics tested were determined to be nontoxic and non-teratogenic at singular, water-soluble concentrations. The hazard quotients (HQ) for the pharmaceuticals ranged from 6.10 × 10⁻⁷ to 1.6 × 10⁻⁴, all of which are orders of magnitude below EPA’s levels for concern for harm to aquatic animals. Thus, based on the data from the present study, concentrations of individual pharmaceuticals currently detected in surface water are far below concentrations of effective and lethal concentrations.     

1-methyl substituent and stereochemical effects of 2-phenylcyclopropylamines on the inhibition of rat brain mitochondrial monoamine oxidase A and B

(E)-2-Phenylcyclopropylamine ((E)-TCP), (Z)-2-phenylcyclopropylamine ((Z)-TCP), (E)-1-methyl-2-phenylcyclopropylamine ((E)-MTCP), and (Z)-1-methyl-2-phenylcyclopropylamine ((Z)-MTCP) were synthesized and used to determine to what extent 1-methyl substitution and stereochemistry of 2-phenylcyclopropylamines affect inhibition of monoamine oxidase (MAO). Inhibition of rat brain mitochondrial MAO-A and B by the compounds were measured using serotonin and benzylamine as the substrate, respectively and IC₅₀ values obtained with 95% confidence limits by the method of computation. For the inhibition of MAO-A, (E)-MTCP (IC₅₀=6.2×10^?8M) was found to be 37 times more potent than (Z)-MTCP (IC₅₀=2.3×10^?6 M), whereas the activity of (E)-TCP (IC₅₀=2.9×10^?7 M) was slightly less than that of (Z)-TCP (IC₅₀=2.3×10^?7 M). Similarly, for the inhibition of MAO-B, (E)-MTCP (IC₅₀=6.3×10^?8 M) was 7 times more potent than (Z)-MTCP (IC₅₀=4.7×10^?7 M) and (E)-TCP (IC₅₀=7.8×10^?8 M), 0.6 times as potent as (Z)-TCP (IC₅₀=4.4×10^?8 M). The results suggested that while without 1-methyl group, potency of a (Z)-isomer was comparable to that of (E)-isomer, the methyl group in its (Z)-position was very unfavorable to the inhibition of MAO and that in its (E)-position, the methyl group contributed positively to the potency as found by the fact that (E)-MTCP was 1–5 times more potent than (E)-TCP. In view of the selective inhibition of MAO-A or B, all compounds elicited 4–10 times higher preference for the inhibition of MAO-B over MAO-A and 1-methyl substitution as well as the stereochemical factors did not significantly influence the selectivity.     

Determination of doxorubicin in pharmaceutical preparation and rat plasma with luminol-K3Fe(CN)6 chemiluminescence system

A novel and rapid flow injection chemiluminescence (FI-CL) method was established for the determination of doxorubicin, which was based on the phenomenon that CL intensity of the reaction between K₃Fe(CN)₆ and luminol in alkaline solution could be strongly enhanced by doxorubicin. Under optimum conditions, the relative CL intensity of the system was linear with the concentration of doxorubicin in the range from 2.0 × 10^?9 g/mL to 5.0 × 10^?7 g/mL with a correlation coefficient of 0.9993 (n = 9). The detection limit (3σ) was 4.25 × 10^?10 g/mL, and the relative standard deviation (RSD) for 1.0 × 10^?7 g/mL doxorubicin (n = 11) was 0.33%. The method was applied to the determination of doxorubicin in pharmaceutical preparation and rat plasma, and the percentage recovery of doxorubicin in rat plasma was between 89.8% and 102.2%. The possible CL mechanism was also discussed briefly.     

Inhibition of CYP2C9 by selective serotonin reuptake inhibitors: in vitro studies with tolbutamide and (S)-warfarin using human liver microsomes

Objective: To investigate the in vitro potential of selective serotonin reuptake inhibitors (SSRIs) to inhibit two CYP2C9-catalysed reactions, tolbutamide 4-methylhydroxylation and (S)-warfarin 7-hydroxylation. Methods: The formation of 4-hydroxytolbutamide from tolbutamide and that of 7-hydroxywarfarin from (S)-warfarin as a function of different concentrations of SSRIs and some of their metabolites was studied in microsomes from three human livers. Results: Both tolbutamide 4-methylhydroxylation and (S)-warfarin 7-hydroxylation followed one enzyme Michaelis-Menten kinetics. Kinetic analysis of 4-hydroxytolbutamide formation yielded a mean apparent Michaelis-Menten constant (K_m) of 133 μM and a mean apparent maximal velocity (V_max) of 248 pmol · min⁻¹ · mg⁻¹; formation of 7-hydroxywarfarin yielded a mean K_m of 3.7 μM and a mean V_max of 10.5 pmol · min⁻¹ ·  mg⁻¹. Amongst the SSRIs and some of their metabolites tested, only fluvoxamine markedly inhibited both reactions. The average computed inhibition constant (K_i) values and ranges of fluvoxamine when tolbutamide and (S)-warfarin were used as substrate, were 13.3 (6.4–17.3) μM and 13.0 (8.4–18.7) μM, respectively. The average K_i value of fluoxetine for (S)-warfarin 7-hydroxylation was 87.0 (57.0–125) μM. Conclusion: Amongst the SSRIs tested, fluvoxamine was shown to be the most potent inhibitor of both tolbutamide 4-methylhydroxylation and (S)-warfarin 7-hydroxylation. Fluoxetine, norfluoxetine, paroxetine, sertraline, desmethylsertraline, citalopram, desmethylcitalopram had little or no effect on CYP2C9 activity in vitro. This is consistent with in vivo data indicating that amongst the SSRIs, fluvoxamine has the greatest potential for inhibiting CYP2C9-mediated drug metabolism. Received: 20 July 1998 / Accepted in revised form: 6 October 1998     

Inhibition of rat brain monoamine oxidase by formamidines and related compounds

The efficacy of the pesticide chlordimeform or N′-(4-chloro-o-tolyl)-N,N′-dimethylform-amidine, six chlordimeform metabolites, and eleven related compounds as inhibitors of the oxidative deamination of radiocarbon-labelled biogenic amines by rat brain monoamine oxidase was examined. The I₅₀ value for chlordimeform with tyramine as substrate was 6.0 × 10^?5M. Inhibition following prolonged pre-incubation of chlordimeform with monoamine oxidase increased with time. and this was attributed, at least in part, to the formation of the more potent monoamine oxidase inhibitor 4′-chloro-o-formotoluidide, a known chlordimeform metabolite and degradation product. 4′-Chloro-o-formotoluidide was the most potent monoamine oxidase inhibitor examined yielding I₅₀ values of 2.6 × 10^?6m. 1.5 × 10^?6M and 3.2 × 10^?6M, with tyramine, dopamine, and serotonin, respectively, as substrates. The N-demethyl (demethylchlordimeform) and N-didemethyl chlordimeform metabolites gave I₅₀ values with tyramine of 3.3 × 10^?5M and 7.5 × 10^?5M, respectively. Three additional metabolites, 4-chloro-o-toluidine, 5-chloroanthranilic acid, and N-formyl-5-chloroanthranilic acid, were weak inhibitors with I₅₀ values of 1 × 10^?4m or higher. The other formamidine compounds also inhibited the oxidative deamination of tyramine; I₅₀ values ranged from 9.3 × 10^?5m to 7.5 × 10^?6m. Lineweaver-Burk plots revealed that chlordimeform, demethylchlordimeform, and 4′-chloro-o-formotoluidide were competitive inhibitors of the oxidative deamination of β-phenylethylamine, tyramine, dopamine, tryptamine, and serotonin. Inhibition was reversible since activity was restored by washing.     

Impact of Custodiol-N cardioplegia on acute kidney injury after cardiopulmonary bypass

Myocardial protection during cardiopulmonary bypass (CPB) can be achieved using cardioplegic solutions. Although, acute kidney injury (AKI) is a common complication following CPB, the effects of cardioplegic solutions on AKI have rarely been investigated. Within this study, the effects of the cardioplegic solutions histidine-tryptophan-ketoglutarate (HTK; Custodiol) and HTK-N (Custodiol-N) on AKI in a large animal model were compared. Therefore, Landrace pigs underwent median sternotomy, CPB at 34°C, 90 minutes of cardiac arrest and 120 minutes of reperfusion. Animals were randomized for single-shot cardioplegia with either HTK (n = 10) or HTK-N (n = 10). Renal biopsies and sera were analyzed to determine AKI biomarkers and apoptosis. Compared to HTK, HTK-N induced a decreased extent of proximal tubule swelling (48.3 ± 1.6 µm vs 52.3 ± 1.1 µm, P = .05) and decreased cytochrome c release (0.26 ± 0.04 vs 0.46 ± 0.08, P = .04) without reaching statistical significance due to Bonferroni correction. Comparing baseline and postreperfusion levels, the hemoglobin (Hb) and blood calcium levels were lower in HTK-N (Hb_baseline: 6.0 ± 0.6 mmol/L, Hb_reperfusion: 6.2 ± 0.7 mmol/L, P = .12; Ca²⁺_baseline: 1.36 ± 0.05 mmol/L, Ca²⁺_reperfusion: 1.28 ± 0.05 mmol/L, P = .16) compared to the HTK group (Hb_baseline: 5.9 ± 0.4 mmol/L, Hb_reperfusion: 4.7 ± 0.8 mmol/L, P < .01; Ca²⁺_baseline: 1.34 ± 0.07 mmol/L, Ca²⁺_reperfusion: 1.24 ± 0.06 mmol/L, P < .01). The present study showed that HTK-N could positively affect the kidney during CPB. Hb and calcium levels were stabilized. A statistical trend was found showing that AKI-related proximal tubule swelling and cytochrome c release were diminished.     

Constriction of rat extra-splenic veins to lipopolysaccharide involves endothelin-1

The spleen has an important role in blood volume regulation and increased resistance of post-capillary hilar veins (in mesentery adjoining the spleen) can regulate this. This study investigated whether venular constriction to lipopolysaccharide (LPS) involved endothelin-1 (ET-1). Pressure myography was used to study isolated extra-splenic (hilar) vessels from male Wistar rats (n = 111). Arteries and veins were treated with LPS (50 μg ml⁻¹) for 4 h. Extra-splenic veins constricted to LPS (p < 0.05), but there was no effect on arteries. Denudation did not abolish venular constriction to LPS, indicating an endothelial independent mechanism. However, the dual ET-1 receptor antagonist bosentan (10⁻⁵ M) and specific ET_A and ET_B antagonists ABT-627 (atrasentan, 6.3 × 10⁻⁶ M) and A-192621(1.45 × 10⁻⁶ M) completely abolished constriction of LPS-treated veins. ET-1 alone also constricted the extra-splenic arteries and veins (p < 0.05), with a greater response observed in veins (p < 0.05). ELISA also confirmed that serum and spleen levels of ET-1 increased in response to LPS (p < 0.05). That LPS-induced constriction of extra-splenic veins is mediated by ET-1. Greater constriction of post- versus pre-capillary extra-splenic vessels to LPS would result in increased intra-splenic fluid extravasation and hypovolaemia in vivo.     

Studies on a new potential dopaminergic agent: in vitro BBB permeability,in vivo behavioural effects and molecular docking evaluation

2-Amino-N-[2-(3,4-dihydroxy-phenyl)-ethyl]-3-phenyl-propionamide (DA-PHEN) has been previously synthesized to obtain a potential prodrug capable of release dopamine (DA) into CNS. However, DA-PHEN could act per se as a dopaminergic drug. In this study, the permeability transport (P_e), obtained by parallel artificial permeability assay (PAMPA), indicated a low passive transcellular transport (P_e?=?0.32?±?0.01?×?10^?6?cm/s). Using the Caco-2 cell system, the P_{app AP-BL} in absorptive direction (3.36?±?0.02?×?10^?5?cm/s) was significantly higher than the P_{app BL-AP} in secretive direction (1.75?±?0.07?×?10^?5?cm/s), suggesting a polarized transport. The efflux ratio (P_{app AP-BL}/P_{app BL-AP}?=?0.52?±?0.02) indicated a low affinity of DA-PHEN to efflux carriers. The forced swim test highlighted a reduction of immobility time in both pre-test and test sessions (p?<?0.0001), with an exacerbation in the number of headshakes and divings in the pretest (p?<?0.0001). Morris water maze strengthened the hypothesis that DA-PHEN induces adaptive responses to environmental challenges which are involved on cognitive functions (DA-PHEN versus CTR: escape latency; p?<?0.001; distance swum p?<?0.001, time spent on target quadrant p?<?0.001), without any change in locomotor activity for the administered dose. The molecular docking revealed the interaction of DA-PHEN with the identified D1 site mapping human brain receptor.     

Mechanism of action of relaxant effect of Agastache mexicana ssp.mexicana essential oil in guinea-pig trachea smooth muscle

Context: Agastache mexicana ssp. mexicana (Kunth) Lint &; Epling (Lamiaceae), popularly known as ‘toronjil morado’, is used in Mexican traditional medicine for the treatment of several diseases such as hypertension, anxiety and respiratory disorders.

Objective: This study investigates the relaxant action mechanism of A. mexicana ssp. mexicana essential oil (AMEO) in guinea-pig isolated trachea model.

Materials and method: AMEO was analyzed by GC/MS. The relaxant effect of AMEO (5–50?μg/mL) was tested in guinea-pig trachea pre-contracted with carbachol (3?×?10?^??⁶?M) or histamine (3?×?10?^??⁵?M) in the presence or absence of glibenclamide (10?^??⁵?M), propranolol (3?×?10?^??⁶?M) or 2′,5′-dideoxyadenosine (10?^??⁵?M). The antagonist effect of AMEO (10–300?μg/mL) against contractions elicited by carbachol (10?^??¹⁵–10?^??³?M), histamine (10?^??¹⁵–10?^??³?M) or calcium (10–300?μg/mL) was evaluated.

Results: Essential oil composition was estragole, d-limonene and linalyl anthranilate. AMEO relaxed the carbachol (EC_50?=_?18.25?±?1.03?μg/mL) and histamine (EC_50?=_?13.3?±?1.02?μg/mL)-induced contractions. The relaxant effect of AMEO was not modified by the presence of propranolol, glibenclamide or 2′,5′-dideoxyadenosine, suggesting that effect of AMEO is not related to β₂-adrenergic receptors, ATP-sensitive potassium channels or adenylate cyclase activation. AMEO was more potent to antagonize histamine (pA₂′?=??1.507?±?0.122) than carbachol (pA₂′?=??2.180?±?0.357). Also, AMEO antagonized the calcium chloride-induced contractions.

Conclusion: The results suggest that relaxant effect of AMEO might be due to blockade of calcium influx in guinea-pig trachea smooth muscle. It is possible that estragole and d-limonene could contribute majority in the relaxant effect of AMEO.     

Binding of new aminopropan-2-ol compounds to bovine serum albumin, α1 acid glycoprotein and rat serum using equilibrium dialysis and LC/MS/MS

BackgroundThe binding of three new aminopropan-2-ol compounds briefly called 2F109, ANBL and TWo8 with potential cardiovascular activity to bovine serum albumin (BSA), α₁-acid glycoprotein (AGP) and to rat serum was studied. The chemical structures of these compounds are related to carvedilol. They possess an antiarrhythmic and hypotensive activity, and β- and α-adrenolytic mechanism of action. All analogues are weak bases with pKa values 8.65,8.85 and 8.26 for 2F109, ANBL and TWo8, respectively, and they possess lipophilic character (log P > 1.9584).MethodsThe extent of protein binding was determined using equilibrium dialysis in the range 2.5 – 900 μM, and 2.5 – 300 μM for binding of investigated compounds to BSA and AGP, respectively, and the quantitative measurement was done by LC/ESI-MS/MS assay.ResultsThe studied compounds bound to a single class of binding sites on BSA which was characterized by low affinity (K_d for 2F109 = 8.49 × 10^–5 M, for ANBL = 1.92 × 10^–5 M, and for TWo8 = 1.71 × 10^–5 M) and low capacity(n = 0.53 for 2F109,0.132 for ANBL and 0.13 for TWo8). The binding of 2F109, ANBL and TWo8 to AGP revealed one class of binding sites, with moderate affinity (K_d for 2F109 = 4.67 × 10^–6 M, for ANBL = 3.48 × 10^–5 M, and for TWo8 = 1.13 × 10^–5 M) and higher capacity (n = 2.21 for 2F109, 2.76 for ANBL and 2.28 for TWo8).ConclusionThe obtained data indicate that 2F109, ANBL and TWo8 moderately bind to BSA (34.2 – 71.2%) with low capacity (K_a = 6.21 × 10³–7.61 × 10³ M^–1)and strongly bind to AGP(71.5–85.5%)with moderate affinity (K_a = 7.94 × 104⁴.73 ×10⁵ M^–1).     

Electrochemical behavior of paclitaxel and its determination at glassy carbon electrode

The electrochemical behavior of paclitaxel drug was studied at a glassy carbon electrode in phosphate buffer solutions using cyclic and differential-pulse voltammetric techniques. The oxidation process was shown to be irreversible over the pH range (3.0–10.4) and was diffusion controlled. Effects of anodic peak potential (E_p), anodic peak current (I_pa), scan rate, pH, heterogeneous rate constant (k⁰), etc have been discussed. A possible electro-oxidation mechanism was proposed. An analytical method was developed for the determination of paclitaxel in phosphate buffer solution at pH = 7.0 as a supporting electrolyte. The anodic peak current varied linearly with paclitaxel concentration in the range 1.0 × 10⁻⁶ M to 1.0 × 10⁻⁵ M with a limit of detection (LOD) of 1.23 × 10⁻⁸ M and limit of quantification (LOQ) of 4.10 × 10⁻⁸ M. The proposed method was successfully applied to the determination of paclitaxel in pure and real samples.     

Determination of lamivudine and zidovudine permeability using a different ex vivo method in Franz cells

IntroductionThe major processes that control the absorption of orally administered drugs are dissolution and gastrointestinal permeation. These processes depend on two main properties: solubility and permeability. Based on these characteristics, the Biopharmaceutical Classification System (BCS) was proposed as a tool to assist in biowaiver and bioavailability prediction of drugs.MethodsThe purpose of the present study was to evaluate the permeability of lamivudine (3TC) and zidovudine (AZT) using a different ex vivo method in Franz cells. A segment of jejunum was inserted in a Franz cells apparatus, in order to assess drug permeability in the apical–basolateral (A–B) and basolateral–apical (B–A) directions. Each drug was added to the donor chamber, collected from the acceptor chamber and analyzed by HPLC. Fluorescein (FLU) and metoprolol (METO) were used as low and high permeability markers, respectively.ResultsThe apparent permeability (P_app) results for the A–B direction were: P_{app FLU A–B} = 0.54 × 10^? 4 cm·s^? 1, P_{app METO A–B} = 7.99 × 10^? 4 cm·s^? 1, P_{app 3TC A–B} = 4.58 × 10^? 4 cm·s^? 1 and P_{app AZT A–B} = 5.34 × 10^? 4 cm·s^? 1. For the B–A direction, the P_app results were: P_{app FLU B–A} = 0.56 × 10^? 4 cm·s^? 1, P_{app METO B–A} = 0.25 × 10^? 4 cm·s^? 1, P_{app 3TC B–A} = 0.24 × 10^? 4 cm·s^? 1 and P_{app AZT B–A} = 0.19 × 10^? 4 cm·s^? 1.DiscussionFor the A–B direction, the P_app results of fluorescein and metoprolol show low and high permeability, respectively, indicating that the membranes were appropriate for permeability studies. For the A–B direction, the P_app results of 3TC and AZT suggest that these antiretroviral drugs have permeability values close to metoprolol. Nevertheless, for the B–A direction the P_app results do not suggest efflux mechanism for any of the drugs. Thereby, the different ex vivo methods using Franz cells can be successfully applied in drug permeability studies, in particular for drug biopharmaceutical classification.