RESUMO
The present study aimed to investigate the effect of AZT derivates containing tellurium (Te) on human breast cancer cell lines and the mechanisms underlying cell death. The inhibitory effect of AZT and its derivatives (7m and 7r) was determined by the MTT assay (6.25, 12.5, 25, 50 and 100 µM in 24 and 48 h time points), meanwhile the induction of apoptosis and the cell cycle phases was investigated by flow cytometry. The MTT assay showed that AZT derivatives decreased the rate of cell proliferation at concentrations of 12.5 µM, while commercial AZT showed low antitumor potential. In flow cytometric analysis, we demonstrate that the AZT derivatives do not induce apoptosis at the concentration tested and promote the cell cycle arrest in the S phase. Besides, predicted absorption, distribution, metabolization, excretion and toxicity analysis suggest that the compounds possess a good pharmacokinetic profile and possibly less toxicity when compared to conventional AZT. These compounds containing tellurium in their formulation are potential therapeutic agents for breast cancer.
Assuntos
Antineoplásicos/síntese química , Zidovudina/análogos & derivados , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Feminino , Meia-Vida , Humanos , Pontos de Checagem da Fase S do Ciclo Celular/efeitos dos fármacos , Telúrio/química , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Zidovudina/síntese química , Zidovudina/farmacocinética , Zidovudina/farmacologiaRESUMO
Considering a novel series of zidovudine (AZT) derivatives encompassing selenoaryl moieties promising candidates as therapeutics, we examined the toxicities elicited by AZT and derivatives 5'-(4-Chlorophenylseleno)zidovudine (SZ1); 5'-(Phenylseleno)zidovudine (SZ2); and 5'-(4-Methylphenylseleno)zidovudine (SZ3) in healthy cells and in mice. Resting and stimulated cultured human peripheral blood mononuclear cells (PBMCs) were treated with the compounds at concentrations ranging from 10 to 200 µM for 24 and/or 72 h. Adult mice received a single injection of compounds (100 µmol/kg, s.c.) and 72 h after administration, hepatic/renal biomarkers were analyzed. Resting and stimulated PBMCs exposed to SZ1 displayed loss of viability, increased reactive species production, disruption in cell cycle, apoptosis and increased transcript levels and production of pro-inflammatory cytokines. In a mild way, most of these effects were also induced by SZ2. AZT and SZ3 did not cause significant toxicity towards resting PBMCs. Differently, both compounds elicited apoptosis and S phase arrest in stimulated cells. AZT and derivatives administration did not change the body weight and plasma biochemical markers in mice. However, the absolute weight and organ-to-body weight ratio of liver, kidneys and spleen were altered in AZT, SZ1-, and SZ2-treated mice. Our results highlighted the involvement of derivatives SZ1 and SZ2 in redox and immunological dyshomeostasis leading to activation of apoptotic signaling pathways in healthy cells under different division phases. On the other hand, the derivative SZ3 emerged as a promising candidate for further viral infection/antitumor studies as a new effective therapy with low toxicity for immune cells and after acute in vivo treatment.
Assuntos
Antineoplásicos/toxicidade , Calcogênios/toxicidade , Leucócitos Mononucleares/efeitos dos fármacos , Zidovudina/toxicidade , Animais , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Comportamento Animal/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica , Humanos , Mediadores da Inflamação/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/patologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Tamanho do Órgão/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Medição de Risco , Pontos de Checagem da Fase S do Ciclo Celular/efeitos dos fármacos , Zidovudina/análogos & derivadosRESUMO
Acquired immunodeficiency syndrome (AIDS) is a worldwide disease characterized by impairments of immune function. AIDS can be associated with oxidative stress (OS) that can be linked to selenium (Se) deficiency. Se is fundamental for the synthesis of selenoproteins, such as glutathione peroxidase and thioredoxin reductase. These enzymes catalyze the decomposition of reactive oxygen species and contribute to maintain equilibrium in cell redox status. Literature data indicate that organoselenium compounds, such as ebselen and diphenyl diselenide, have antioxidant properties in vitro and in vivo models associated with OS. Nevertheless, selenocompounds can also react and oxidize thiols groups, inducing toxicity in mammals. Here, we tested the potential cytotoxic and genotoxic properties of six analogs of the prototypal anti-HIV drug azidothymidine (AZT) containing Se (5'-Se-(phenyl)zidovudine; 5'-Se-(1,3,5-trimethylphenyl)zidovudine; 5'-Se-(1-naphtyl)zidovudine; 5'-Se-(4-chlorophenyl)zidovudine) (C4); 5'-Se-(4-methylphenyl)zidovudine (C5); and 5'-(4-methylbenzoselenoate)zidovudine). C5 increased the rate of dithiothreitol oxidation (thiol oxidase activity) and C2-C4 and C6 (at 100 µM) increased DNA damage index (DI) in human leukocytes. Moreover, C5 (200 µM) decreased human leukocyte viability to about 50%. Taken together, these results indicated the low in vitro toxicity in human leukocytes of some Se-containing analogs of AZT.
Assuntos
Fármacos Anti-HIV/toxicidade , Leucócitos/efeitos dos fármacos , Compostos Organosselênicos/toxicidade , Zidovudina/análogos & derivados , Zidovudina/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Ensaio Cometa , Dano ao DNA , HumanosRESUMO
Zidovudine (AZT) was the first drug approved for the treatment of Acquired Immunodeficiency Syndrome (AIDS) in humans, and although its clinical efficacy has been demonstrated, suboptimal pharmacokinetic aspects still remain a concern. To assess the basis of its highly variable oral bioavailability, this work deals with the study of AZT intestinal absorption by applying the gut sac technique. Permeation through the rat jejunum and ileum segments was analyzed at different drug concentrations and gut regions, with higher apparent permeability coefficients (P(app)) being found for the proximal regions of the small intestine compared to distal ones. Bi-directional permeation assays demonstrated that AZT is subjected to efflux mechanisms in distal regions of small intestine, which are blocked by verapamil (VER), thus demonstrating a P-glycoprotein (P-gp) mediated mechanism. The efficiency of AZT efflux increased in the distal ileum as consequence of exposure to AZT, with the amount of drug permeating from the mucosal to the serosal side diminishing after 35 min. Molecular modeling techniques were applied to analyze the binding mode of AZT to P-gp, which was compared to that of VER and AZT-Ac, a novel prodrug of AZT. The energy required for their solvation was found to constitute a critical feature in their binding to this efflux protein. The present work updates the impact of P-gp in AZT oral bioavailability, highlighting the need for further study of the dynamic nature of its expression at intestinal level.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Fármacos Anti-HIV/farmacocinética , Absorção Intestinal/fisiologia , Verapamil/farmacologia , Zidovudina , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Sítios de Ligação , Disponibilidade Biológica , Transporte Biológico , Humanos , Íleo/metabolismo , Jejuno/metabolismo , Masculino , Modelos Moleculares , Mucosa/metabolismo , Permeabilidade , Pró-Fármacos/análise , Pró-Fármacos/farmacocinética , Ratos , Ratos Wistar , Membrana Serosa/metabolismo , Zidovudina/análogos & derivados , Zidovudina/análise , Zidovudina/farmacocinéticaRESUMO
This work studies the stability of three new anti-HIV agents which were obtained by the association of zidovudine (AZT) with different amino acids, such as leucine (AZT-Leu) and valine (AZT-Val), and one with an acid group (AZT-Ac). Before commercialisation, their stability in different matrices - simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 6.8), both as the USP 32 Guideline indicates, and buffers (pH 1.2 and 6.8) - must be studied. To this end, a new stability-indicating micellar liquid chromatography (MLC) method has been optimised and validated. Measurements were based on the disappearance of reagents and the appearance of the only degradation product (AZT). This optimised and validated method used a C18 column and a mobile phase containing 0.05 M sodium dodecyl sulphate-1% (v/v)1-butanol-0.01 M NaH(2)PO(4) (pH 3.0) at 30°C, and a flow rate of 1 mL min(-1). Under these conditions, retention times were 1.4, 3.6, 6.3 and 9.5 min for AZT-Ac, AZT, AZT-Val and AZT-Leu, respectively. Calibrations better than 0.9995, intra- and inter-day precisions below 1.08% and good recoveries (94.47-116.52%) and robustness (RSD less that 1.08%) were obtained and were adequate to analyse the four compounds. Finally, this MLC method was applied to achieve stability studies which resulted in the evidence that all the compounds followed a pseudo-first-order kinetics, and in the determination of their kinetic constants and half-life time. A reference method, applied in the same studies, validated the MLC method reported herein.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Suco Gástrico/química , Micelas , Zidovudina/análogos & derivados , Líquidos Corporais/química , Estabilidade de Medicamentos , Humanos , Concentração de Íons de Hidrogênio , Intestinos/química , Modelos Biológicos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Zidovudina/análiseRESUMO
This work deals with the in vitro and in vivo pharmacokinetic characterization of 3'-azido-2',3'-dideoxy-5'-O-oxalatoylthymidine (AZT-Ac) and 3'-azido-2',3'-dideoxy-5'-O-isonicotinoyl-thymidine (AZT-Iso), two novel prodrugs of the anti-HIV agent zidovudine [3'-azido-2',3'-dideoxythymidine (AZT)]. AZT, AZT-Ac and AZT-Iso intestinal permeation properties and plasma concentration profiles in rats after intravenous administration were studied. Using the everted gut sac intestinal permeation assay, it was observed that AZT was subjected to saturable transport mechanisms in the jejunum and the proximal ileum, while no saturation was found in the distal ileum. AZT-Ac was able to permeate the intestinal segment at a lower rate than AZT but resisting enzymatic hydrolysis, while no evidence of saturation was found. On the other hand, AZT-Iso was completely hydrolyzed in the intestinal tissue, with AZT being found in the permeated samples. In vivo studies demonstrated that AZT plasma half-life (t(1/2)) is extended after administration of AZT-Ac compared to AZT (2.16 and 0.96h, respectively), while after administering AZT-Iso the t(1/2) of the regenerated AZT was shorter (0.38h). A relationship is proposed between these observed in vivo pharmacokinetic features and previous studies of protein-binding properties, concluding that AZT-Ac is a very promising prodrug of AZT in the search for more effective and safer anti-HIV agents.
Assuntos
Fármacos Anti-HIV/farmacocinética , Pró-Fármacos/farmacocinética , Zidovudina/análogos & derivados , Zidovudina/farmacocinética , Animais , Fármacos Anti-HIV/administração & dosagem , Meia-Vida , Injeções Intravenosas , Intestinos/química , Masculino , Estrutura Molecular , Plasma/química , Pró-Fármacos/administração & dosagem , Ratos , Zidovudina/administração & dosagemRESUMO
This work presents the binding of AZT and nine novel AZT derivatives to human serum albumin (HSA), both defatted (HSA(D)) and complexed with fatty acids (HSA(FA)). The bound fractions and binding site were determined by applying an ultrafiltration procedure, with an increased affinity for the majority of these derivatives to HSA(D) being found with respect to that of AZT, while only one derivative exhibited an increased affinity for HSA(FA). By means of computational methods, we observed that specific electrostatic interactions are responsible for the increased affinity for HSA(D), while the presence of fatty acids complexed to HSA caused an intense electrostatic repulsion with negatively charged ligands located in Sudlow site I, thus diminishing their bound fractions. A strong relationship between the calculated energetic components and the observed experimental affinity was identified.
Assuntos
Albumina Sérica/metabolismo , Zidovudina/análogos & derivados , Sítios de Ligação , Ácidos Graxos , Humanos , Modelos Moleculares , Ligação Proteica , Eletricidade Estática , Ultrafiltração , Zidovudina/farmacocinéticaRESUMO
In the present paper the relative permeabilities of AZT-Pyp and AZT-Ethy across a phospholipid bilayer were estimated by the means of fluorescence spectroscopy. The center of spectral mass of both non-encapsulated AZT-derivatives (AZT-der) emission spectra increased as a function of the illumination time inside the spectrofluorimeter cell. This phenomenon was even more evident when drugs were incubated under an UV mercury lamp, suggesting its photolytic origin. AZT-der were protected from photolysis inside liposomes and decomposed upon irradiation when they were free in the aqueous phase. The time-dependent decrease in the fluorescence intensity at a constant wavelength was fitted to a two-exponential equation and the values of rate constants for permeability and photolysis were calculated. It was concluded that AZT-Pyp but not AZT-Ethy diffused across the bilayer. This behavior correlated with the molecular volumes of AZT-Pyp (379.6A(3)) and AZT-Ethy (450.5A(3)), determined from the minimum energy conformations but not with previously reported logP values. These results reinforce the concept that not only lipophilicity but also membrane structure and AZT-der molecular size had a critical influence in passive diffusion across bilayers and may help in future refinements of other AZT-der molecular design.
Assuntos
Carbamatos/química , Zidovudina/química , Detergentes/química , Sistemas de Liberação de Medicamentos , Interações Hidrofóbicas e Hidrofílicas , Cinética , Bicamadas Lipídicas/química , Lipossomos , Conformação Molecular , Permeabilidade , Fotólise , Espectrometria de Fluorescência , Fatores de Tempo , Zidovudina/análogos & derivadosRESUMO
OBJECTIVES: To study the effect of antiretroviral drugs administered to pregnant women on hematologic parameters of the neonate. STUDY DESIGN: A prospective cohort study was conducted on 52 neonates divided into three groups: ZDV group, infants born to HIV-infected mothers taking zidovudine (n=18); triple therapy (TT) group, infants born to mothers taking zidovudine+lamivudine+nelfinavir (n=22), and control group, infants born to normal women (n=12). Umbilical cord blood from the newborn infant was used to determine hemoglobin, lymphocyte and platelet. Data were analyzed statistically by the nonparametric tests, with the level of significance set at p<0.05. RESULTS: The major maternal demographic and anthropometric data were homogeneous for the various groups. There was a reduction in hemoglobin levels at birth among TT group newborns (p=0.016). There was no difference between groups regarding gestation length, Apgar scores, platelets or absolute lymphocyte count for the newborn. CONCLUSIONS: An association between the use of combination antiretroviral therapy during pregnancy and reduced neonatal hemoglobin levels was observed, supporting the need for short- and long-term follow-up of infants exposed to antiretroviral drugs during uterine life.
Assuntos
Anemia/induzido quimicamente , Feto/efeitos dos fármacos , Hemoglobinas/efeitos dos fármacos , Inibidores da Transcriptase Reversa/efeitos adversos , Adolescente , Adulto , Plaquetas/efeitos dos fármacos , Didesoxinucleotídeos , Quimioterapia Combinada , Feminino , Sangue Fetal/química , Sangue Fetal/citologia , Infecções por HIV/tratamento farmacológico , Inibidores da Protease de HIV/efeitos adversos , Humanos , Recém-Nascido , Lamivudina/efeitos adversos , Linfócitos/efeitos dos fármacos , Nelfinavir/efeitos adversos , Gravidez , Nucleotídeos de Timina/efeitos adversos , Zidovudina/efeitos adversos , Zidovudina/análogos & derivadosRESUMO
The pH-solubility behavior and solubility of 3'-azido-3'-deoxy-5'-O-isonicotinoylthymidine (AZT-Iso), an antiretroviral derivative of zidovudine with important biological activity, was studied in water, ethanol, ethanol: water, and n-octanol. The N-pyridine pKa value was determined from its pH-solubility profile, which was in accordance with that of the experimental value of methyl isonicotinate. Also, the ethanol cosolvency in ethanol:water mixtures at 25 degrees C was studied, and log-linear and nonlinear solubilization models were applied to the experimental solubility AZT-Iso data, which allowed us to predict its solubility in those solvent mixtures at a determined content of cosolvent.
Assuntos
Antirretrovirais/química , Zidovudina/análogos & derivados , Antirretrovirais/farmacologia , Concentração de Íons de Hidrogênio , Solubilidade , Zidovudina/química , Zidovudina/farmacologiaRESUMO
Degradation of 3'-azido-3'-deoxy-5'-O-isonicotinoylthymidine (AZT-Iso), an antiretroviral derivative of zidovudine, was investigated in buffer pH 7.4, mu = 300 mOsm at 37, 50 and 60 degrees C, and in water (pH 6.6, 37 degrees C), giving zidovudine (AZT) and isonicotinic acid (INA) as products. The rate constants were determined by reversed-phase HPLC showing pseudo-first-order kinetics related to the residual amount of AZT-Iso. In this way, the studied compound was demonstrated to be 153 times more stable in water than in buffer solution at 37 degrees C. The analytical method was conveniently validated demonstrating to be a rapid and accurate stability-indicating technique. In addition, experimental and theoretical values of pKa were determined.
Assuntos
Fármacos Anti-HIV/química , Zidovudina/química , Cromatografia Líquida de Alta Pressão/métodos , Ácidos Isonicotínicos/química , Cinética , Estrutura Molecular , Água/química , Zidovudina/análogos & derivadosRESUMO
In this paper we investigate (using AM1 semi-empirical as well as HF methods at the STO-3G, 3-21G, 6-31G, 6-31G* and 6-31+G** level) the conformations, geometrical parameters, Mulliken charges, and solvation effects of the triphosphate form of AZT (AZTTP), as well as the thymidine nucleotide (dTTP) structure. Our calculated geometrical parameters and Mulliken charges, with and without solvation effects, are correlated with recent experimental results.
Assuntos
Modelos Teóricos , Nucleotídeos de Timina/química , Zidovudina/análogos & derivados , Zidovudina/química , Didesoxinucleotídeos , EstereoisomerismoRESUMO
Conformational properties of three novel zidovudine analogs, namely 3'-azido-3'-deoxy-5'-O-isonicotinoylthymidine (AZT-Iso, 2), (-)-trans-(5S,6S)-5-bromo-6, 5'-epoxy-5,6-dihydro-3'-azido-3'-deoxythymidine (3) and (+)-trans-(5R,6R)-5-bromo-6,5'-epoxy-5,6-dihydro-3'-azido-3'-deoxythymidine (4), have been investigated by AM1 calculations and NMR studies, and compared with those of the parent nucleoside (AZT, 1). Based on the results obtained the following correlation may be established, a) AZT and AZT-Iso exhibit a conformational behavior analog to other pyrimidinic nucleosides, displaying a dynamic equilibrium in solution where the two conformers (North and South) undergo a constant transformation. b) Compounds 3 and 4 show a different conformational profile. The estimate of the pseudorotation phase angle reveals the rigid structures of the latter compounds, which do not evidence conformational equilibrium in solution; the azide group being the only group free to rotate. c) Diastereoisomers 3 and 4 exhibit an extra conformational parameter compared with other pyrimidinic nucleosides: the chair or boat conformation in the third ring formed between the sugar and the base. In all cases, a reasonable correlation was obtained between theoretical and NMR spectroscopic data.
Assuntos
Antirretrovirais/química , Zidovudina/análogos & derivados , Espectroscopia de Ressonância Magnética , Conformação Molecular , Zidovudina/químicaRESUMO
An efficient, short synthesis of four potential prodrugs of 3'-azido-3'-deoxythymidine (AZT) and their antibacterial activity are reported. The 5'-OH group of AZT was functionalized with oxalyl chloride obtaining an acyl chloride derivative (AZT-Ox), which by further transformation with leucine, isoleucine and valine amino acids led to the corresponding AZT analogs, namely AZT-Leu, AZT-iLeu and AZT-Val. A carboxyl acid derivative (AZT-Ac) was also obtained by hydrolysis of AZT-Ox. These compounds, which exhibit anti HIV activity, have killed collection and clinical strains of some opportunistic infectious agents in AIDS-related complex. Thus, the clinical strains, K. oxytoca, S. typhi and K. pneumoniae, and collection strain K. pneumoniae ATCC 10031 showed sensitivity to antibiotics. The activity order for the studied compounds against the most sensitive strain (K. pneumoniae ATCC 10031) was AZT-Leu > AZT-iLeu > AZT-Val > AZT-Ac > AZT. On the other hand, the activity order for the second most sensitive strain (K. oxytoca) was AZT-Leu > AZT-Val = AZT-Ac > AZT-iLeu > AZT. The most effective antibacterial drug AZT-Leu, M.I.C.=0.125 microgmL(-1)) was 16 times more active than AZT (AZT, M.I.C.=2 microg mL(-1)) against K.
Assuntos
Anti-Infecciosos/síntese química , Pró-Fármacos/síntese química , Zidovudina/análogos & derivados , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/farmacologia , Anti-Infecciosos/farmacologia , HIV-1/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pró-Fármacos/farmacologia , Zidovudina/síntese química , Zidovudina/farmacologiaRESUMO
The binding of novel nucleoside derivatives (2-7) to the Human Serum Albumin (HSA) was studied using zidovudine (AZT), as standard compound. The applicability of two different techniques to separate unbound drug from drug-protein complex was analyzed: the gel filtration and ultrafiltration methods. Ultrafiltration was found to be an adequate procedure for the separation of unbounded drug from the drug-protein complex. Incubation temperature ranging from 0 to 37 degrees C did not modify considerably the bound fractions. The same effects were observed as HSA concentration was modified. Binding assays of studied compounds to purified 1% (w/v) HSA at 0 degrees C, indicate that bound fraction of 2-7 ranges from 13 to 47%, exhibiting a higher affinity to HSA than AZT (12%), which would introduce some interesting improvements in their pharmacokinetic properties. In addition, by means of displacement studies using HSA site specific drugs such as diazepam and salicylate, it was determined that AZT binds to site I of the HSA molecule, by a mainly entropy driven process (DeltaS = 10.834 cal/mol degrees K), being these observations extensive to 2-7. Some structural basis to explain enhanced affinity of these novel derivatives was also established.
Assuntos
Albumina Sérica/metabolismo , Zidovudina/análogos & derivados , Zidovudina/metabolismo , Ligação Competitiva , Cromatografia em Gel , Ácidos Decanoicos/metabolismo , Ácidos Decanoicos/farmacologia , Diazepam/metabolismo , Entropia , Humanos , Modelos Moleculares , Pró-Fármacos/química , Pró-Fármacos/metabolismo , Pró-Fármacos/farmacocinética , Ligação Proteica , Estrutura Secundária de Proteína/efeitos dos fármacos , Reprodutibilidade dos Testes , Ácido Salicílico/metabolismo , Albumina Sérica/química , Espectrofotometria Ultravioleta , Especificidade por Substrato , Temperatura , Ultrafiltração , Zidovudina/química , Zidovudina/farmacocinéticaRESUMO
Highly active antiretroviral therapy (HAART) is the standard treatment for infection with human immunodeficiency virus (HIV). The most common HAART regimen consists of the combination of at least one protease inhibitor (PI) with two nucleoside reverse transcriptase inhibitors (NRTIs). Contrary to PIs, NRTIs require intracellular activation from the parent compound of their triphosphate moiety to suppress HIV replication. Simultaneous intracellular determination of two NRTI triphosphates is difficult to accomplish due to their relatively small concentrations in peripheral blood mononuclear cells (PBMCs), requiring large amounts of blood from HIV-positive patients. Recently, we described a method to determine intracellular zidovudine triphosphate (ZDV-TP) concentrations in HIV-infected patients by using solid-phase extraction and tandem mass spectrometry. The limit of quantitation (LOQ) for ZDV-TP was 0.10 pmol, and the method was successfully used for the determination of ZDV-TP in HIV-positive patients. In this study, we enhanced the aforementioned method by the simultaneous quantitation of ZDV-TP and lamivudine triphosphate (3TC-TP) in PBMCs from HIV-infected patients. The LOQ for 3TC-TP was 4.0 pmol, with an interassay coefficient of variation and an accuracy of 7 and 12%, respectively. This method was successfully applied to the simultaneous in vivo determination of the ZDV-TP and 3TC-TP pharmacokinetic profiles from HIV-infected patients receiving HAART.
Assuntos
Fármacos Anti-HIV/sangue , Citidina Trifosfato/sangue , Infecções por HIV/tratamento farmacológico , Lamivudina/sangue , Nucleotídeos de Timina/sangue , Zidovudina/sangue , Fármacos Anti-HIV/uso terapêutico , Cromatografia por Troca Iônica , Citidina Trifosfato/análogos & derivados , Didesoxinucleotídeos , Infecções por HIV/sangue , Humanos , Lamivudina/análogos & derivados , Lamivudina/metabolismo , Lamivudina/uso terapêutico , Padrões de Referência , Zidovudina/análogos & derivados , Zidovudina/metabolismo , Zidovudina/uso terapêuticoRESUMO
Nucleoside reverse transcriptase inhibitors (NRTIs) used against the human immunodeficiency virus (HIV) need to be activated intracellularly to their triphosphate moiety to inhibit HIV replication. Intracellular concentrations of these NRTI triphosphates, especially zidovudine triphosphate (ZDV-TP), are relatively low (low numbers of femtomoles per 10(6) cells) in HIV-infected patient peripheral blood mononuclear cells. Recently, several methods have used either high-performance liquid chromatography (HPLC) or solid-phase extraction (SPE) coupled with radioimmunoassay to obtain in vivo measurements of ZDV-TP. The limit of detection (LOD) by these methods ranged from 20 to 200 fmol/10(6) cells. In this report, we describe the development of a method to determine intracellular ZDV-TP concentrations in HIV-infected patients using SPE and HPLC with tandem mass spectrometry for analysis. The LOD by this method is 4.0 fmol/10(6) cells with a linear concentration range of at least 4 orders of magnitude from 4. 0 to 10,000 fmol/10(6) cells. In hispanic HIV-infected patients, ZDV-TP was detectable even when the sampling time after drug administration was 15 h. Intracellular ZDV-TP concentrations in these patients ranged from 41 to 193 fmol/10(6) cells. The low LOD obtained with this method will provide the opportunity for further in vivo pharmacokinetic studies of intracellular ZDV-TP in different HIV-infected populations. Furthermore, this methodology could be used to perform simultaneous detection of two or more NRTIs, such as ZDV-TP and lamivudine triphosphate.
Assuntos
Fármacos Anti-HIV/sangue , Infecções por HIV/sangue , Monócitos/metabolismo , Nucleotídeos de Timina/sangue , Zidovudina/análogos & derivados , Adulto , Idoso , Calibragem , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Didesoxinucleotídeos , Feminino , Humanos , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Nucleotídeos/sangue , Padrões de Referência , Zidovudina/sangueRESUMO
A novel cyclic bromine zidovudine analog, (-)-trans-(5S,6S)-5-bromo-6,5'- epoxy-5,6-dihydro-3'-azido-3'-deoxythymidine (2), and its diastereoisomer (+)-trans-(5R,6R)-(3) were synthesized and characterized by spectroscopic methods, obtaining 3 in very low yields. The major product 2 presents a selectivity index (CCID50/IC50) similar to zidovudine but 55.5 times with higher lipophilicity, which should increase the ability of 2 to cross the blood-brain barrier by a non facilitated diffusion mechanism.
Assuntos
Fármacos Anti-HIV/síntese química , HIV-1/efeitos dos fármacos , Zidovudina/análogos & derivados , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Estabilidade de Medicamentos , Sangue Fetal , Humanos , Monócitos/citologia , Monócitos/efeitos dos fármacos , Estereoisomerismo , Zidovudina/síntese química , Zidovudina/química , Zidovudina/farmacologiaRESUMO
This study evaluated the safety, tolerability, and pharmacokinetics of zidovudine administered intravenously and orally to infants born to women infected with the human immunodeficiency virus. Thirty-two symptom-free infants were enrolled before 3 months of age. The pharmacokinetics of zidovudine were evaluated in each infant after single intravenously and orally administered doses of zidovudine on consecutive days, and during long-term oral administration of the drug for 4 to 6 weeks. As new patients were enrolled, doses of zidovudine were progressively increased from 2 to 4 mg/kg. Therapy was continued for up to 12 months in 7 of the infants proved to be infected with human immunodeficiency virus. Zidovudine was generally well tolerated; 20 children (62.5%) had anemia (hemoglobin level < 10.0 gm/dl) during therapy and 9 (28.1%) had neutropenia (neutrophil count < or = 750 cells/mm3); these hematologic abnormalities usually resolved spontaneously. The total body clearance of zidovudine increased significantly with age, from an average of 10.9 ml/min per kilogram in infants < or = 14 days of age to 19.0 ml/min per kilogram in older infants (p < 0.0001). Concurrently, there was a significant decrease in serum half-life from 3.12 hours in infants < or = 14 days to 1.87 hours in older infants (p = 0.0002). Oral absorption was satisfactory and bioavailability decreased significantly with age, from 89% in infants < or = 14 days to 61% in those > 14 days of age (p = 0.0002). Plasma concentrations of zidovudine were calculated to be in excess of 1 mumol/L (0.267 micrograms/ml) for 4.12 +/- 1.86 hours and 2.25 +/- 0.78 hours after oral doses of 2 mg/kg in infants younger than 2 weeks and 3 mg/kg in older infants, respectively. We conclude that zidovudine administered at oral doses of 2 mg/kg every 6 hours to infants aged less than 2 weeks and 3 mg/kg every 6 hours to infants older than 2 weeks resulted in plasma concentrations that are considered virustatic against human immunodeficiency virus. Zidovudine was well tolerated by infants at these doses.