RESUMO
OBJECTIVE: For the treatment of HIV-1-related brain disease and for the prevention of the brain becoming a viral reservoir, it is important that antiretroviral agents reach sufficient concentrations in the CNS. To date, human brain pharmacokinetic data are solely derived from lumbar cerebrospinal fluid (CSF) and mostly originate from single samples. DESIGN: We determined concentrations of antiretroviral drugs in serial samples of ventricular CSF and compared these to the concentrations in serum and lumbar CSF of these patients. METHODS: Two treatment-naïve HIV-1-infected patients received external ventricular drainage for obstructive hydrocephalus. Starting with a combination antiretroviral regimen (cART), ventricular CSF, and subsequently lumbar CSF, with parallel serum, was frequently collected. Drug concentrations were determined and CSF-to-serum ratios were calculated. RESULTS: High concentrations, resulting in high CSF-to-serum ratios, were found in the ventricular CSF of the three substances zidovudine, lamivudine and indinavir, whereas this was not observed for stavudine, ritonavir, saquinavir and efavirenz. Concentrations of zidovudine and lamivudine were up to four times greater in CSF from the ventricles than in lumbar CSF of the same patient. The zidovudine concentrations in the ventricular CSF exceeded serum concentrations by a factor of 1.4. CONCLUSION: Unexpectedly high concentrations of some antiretrovirals in the ventricular CSF, the site close to the brain parenchyma where HIV is located, should be considered when the cART regimen is aiming at CNS viral replication.
Assuntos
Fármacos Anti-HIV/líquido cefalorraquidiano , Fármacos Anti-HIV/farmacocinética , Infecções por HIV/tratamento farmacológico , Lamivudina/líquido cefalorraquidiano , Lamivudina/farmacocinética , Zidovudina/líquido cefalorraquidiano , Zidovudina/farmacocinética , Complexo AIDS Demência/prevenção & controle , Adulto , Fármacos Anti-HIV/sangue , Fármacos Anti-HIV/uso terapêutico , Quimioterapia Combinada , Infecções por HIV/metabolismo , HIV-1/genética , Humanos , Lamivudina/sangue , Lamivudina/uso terapêutico , Masculino , RNA Viral/sangue , RNA Viral/líquido cefalorraquidiano , Punção Espinal , Estavudina/administração & dosagem , Estavudina/sangue , Estavudina/líquido cefalorraquidiano , Estavudina/uso terapêutico , Carga Viral , Zidovudina/sangue , Zidovudina/uso terapêuticoRESUMO
OBJECTIVE: To determine the trough and two hour plasma levels of nevirapine, stavudine, and lamivudine when administered in fixed dose combinations (FDC). DESIGN: Cross sectional. SETTING: Tertiary care hospital in Northern India. PARTICIPANTS: 79 HIV-infected children receiving antiretroviral therapy with FDCs for more than month. INTERVENTION: Two-point sampling (0 and 2 hours after the morning dose). OUTCOME MEASURES: Plasma concentrations of all three drugs were simultaneously assayed by liquid chromatography/mass spectroscopy. RESULTS: Majority (77%) of children were receiving fixed dose combination of stavudine, lamivudine, nevirapine in the ratio of 6:30:50 mg. The median (IQR) trough and 2-hour plasma levels (µg/mL) of nevirapine, stavudine and lamivudine were 5.2 (4.0, 6.3) and 7.9 (6.0, 9.7); 0.1 (0.06, 0.16) and 1.1 (0.59, 1.6); 0.1 (0.02, 0.2) and 2.5 (1.4, 3.1), respectively. Very few children had sub-therapeutic plasma drug levels of stavudine (2.5%), lamivudine (7.6%) and nevirapine (10%). Inadequate viral suppression at 6 months follow up was significantly associated with initial high viral load, low CD4 percentage at the time of enrolment in study, and lower doses of lamivudine and stavudine. CONCLUSIONS: The currently available generic pediatric fixed dose antiretroviral combinations in India provide adequate drug exposure in majority of children.
Assuntos
Fármacos Anti-HIV/farmacocinética , Medicamentos Genéricos/farmacocinética , Infecções por HIV/tratamento farmacológico , Lamivudina/farmacocinética , Nevirapina/farmacocinética , Estavudina/farmacocinética , Adolescente , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/sangue , Fármacos Anti-HIV/uso terapêutico , Criança , Pré-Escolar , Estudos Transversais , Medicamentos Genéricos/administração & dosagem , Medicamentos Genéricos/uso terapêutico , Feminino , Infecções por HIV/epidemiologia , Humanos , Lactente , Lamivudina/administração & dosagem , Lamivudina/sangue , Lamivudina/uso terapêutico , Masculino , Nevirapina/administração & dosagem , Nevirapina/sangue , Nevirapina/uso terapêutico , Estavudina/administração & dosagem , Estavudina/sangue , Estavudina/uso terapêuticoRESUMO
The antiviral efficacy of stavudine depends on the trough concentration of its intracellular metabolite, stavudine-triphosphate (d4T-TP), while the degree of stavudine's mitochondrial toxicity depends on its peak concentration. Rates of mitochondrial toxicity are high when stavudine is used at the current standard pediatric dose (1 mg/kg twice daily [BID]). Evidence from adult work suggests that half of the original standard adult dose (i.e., 20 mg BID) may be equally effective, with markedly less mitochondrial toxicity. We present a population pharmacokinetic model to predict intracellular d4T-TP concentrations in pediatric HIV-infected patients administered a dose of 0.5 mg/kg BID. Our model predicted that the reduced pediatric dose would result in a trough intracellular d4T-TP concentration above that of the reduced 20-mg adult dose and a peak concentration below that of the 20-mg adult dose. The simulated pediatric intracellular d4T-TP at 0.5 mg/kg BID resulted in median peak and trough values of approximately 23.9 fmol/10(6) cells (95% prediction interval [PI], 14.2 to 41 fmol/10(6) cells) and 14.8 fmol/10(6) cells (95% PI, 7.2 to 31 fmol/10(6) cells), respectively. The peak and trough concentrations resulting from a 20-mg BID adult dose were 28.4 fmol/10(6) cells (95% PI, 17.3 to 45.5 fmol/10(6) cells) and 13 fmol/10(6) cells (95% PI, 6.8 to 28.6 fmol/10(6) cells), respectively. Halving the current standard pediatric dose should therefore not compromise antiviral efficacy, while markedly reducing mitochondrial toxicity.
Assuntos
Fármacos Anti-HIV/farmacocinética , Infecções por HIV/tratamento farmacológico , Mitocôndrias/efeitos dos fármacos , Modelos Estatísticos , Estavudina/farmacocinética , Adulto , Fármacos Anti-HIV/sangue , Fármacos Anti-HIV/toxicidade , Criança , Esquema de Medicação , Cálculos da Dosagem de Medicamento , Feminino , HIV/efeitos dos fármacos , HIV/fisiologia , Infecções por HIV/sangue , Infecções por HIV/virologia , Humanos , Masculino , Estavudina/sangue , Estavudina/toxicidadeRESUMO
A methodology based on micellar liquid chromatography to monitor five antiretroviral drugs (lamivudine, stavudine, tenofovir, zidovudine and efavirenz) was proposed. Antiretrovirals were studied in sets of three, corresponding to each highly active antiretroviral therapy (HAART) regime, prescribed to acquired immunodeficiency syndrome (AIDS)-infected patients. Four aqueous micellar mobile phases buffered at pH 7 were optimized to separate these compounds, using sodium dodecyl sulfate as the tensioactive, and 1-propanol or 1-pentanol as the organic modifier. The composition of each mobile phase was optimized for each antiretroviral. The common separation conditions were: C18 apolar column (125 × 4.6 mm, 5 µm particle size), UV detection set at 214 nm, and mobile phase running at 1 mL min(-1) without controlling the temperature. The finally suggested method was validated for five analysed antiretroviral drugs following the US Food and Drug Administration guidelines in terms of: linearity between 0.5 and 50 ppm (r(2) > 0.9995), sensitivity (LOD lower than 0.25 ppm), intra- and inter-day precision (<7.1 and <5.2%, respectively) and accuracy (recovery 88.5-105.3% and 93.5-101.3%, respectively), as well as robustness (<6.5%). The proposed method was used to monitor the level of antiretrovirals in the serum of AIDS patients. The suggested methodology was found to be useful in the routine analysis of antiretrovirals in serum samples.
Assuntos
Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Fármacos Anti-HIV/sangue , Terapia Antirretroviral de Alta Atividade , Monitoramento de Medicamentos , Síndrome da Imunodeficiência Adquirida/sangue , Adenina/análogos & derivados , Adenina/sangue , Adenina/uso terapêutico , Alcinos , Fármacos Anti-HIV/uso terapêutico , Benzoxazinas/sangue , Benzoxazinas/uso terapêutico , Cromatografia Líquida , Ciclopropanos , Humanos , Lamivudina/sangue , Lamivudina/uso terapêutico , Organofosfonatos/sangue , Organofosfonatos/uso terapêutico , Estavudina/sangue , Estavudina/uso terapêutico , Tenofovir , Zidovudina/sangue , Zidovudina/uso terapêuticoRESUMO
A high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method for the simultaneous quantification of lamivudine, stavudine and nevirapine was developed and validated in dried blood spot (DBS) cards. The analytes were separated using an isocratic mobile phase on a reverse phase column and analyzed by MS/MS in the MRM mode using the respective [M + H]⺠ions, m/z 230-112 for lamivudine, m/z 225-127 for stavudine, m/z 267-226 for nevirapine, m/z 383-337 for zidovudine (IS). The lower limit of quantification was 1 ng/mL for both lamivudine and stavudine and 10 ng/mL for nevirapine. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The method was successfully applied to quantify them in a rat pharmacokinetic study in whole blood, plasma and DBS cards after a single oral co-administration at the dose of 10, 2 and 13 mg/kg for lamivudine, stavudine and nevirapine, respectively, to male Wistar rats. Following oral administration the pharmacokinetic results in all the matrices are in close agreement. Thus accomplishment of this method would facilitate the ease of collection of clinical samples on DBS cards for lamivudine, stavudine and nevirapine during human clinical trials and therapeutic drug monitoring.
Assuntos
Antirretrovirais/sangue , Teste em Amostras de Sangue Seco/métodos , Animais , Antirretrovirais/química , Antirretrovirais/farmacocinética , Cromatografia Líquida de Alta Pressão , Estabilidade de Medicamentos , Lamivudina/sangue , Lamivudina/química , Lamivudina/farmacocinética , Masculino , Nevirapina/sangue , Nevirapina/química , Nevirapina/farmacocinética , Ratos , Ratos Wistar , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Estavudina/sangue , Estavudina/química , Estavudina/farmacocinética , Espectrometria de Massas em TandemRESUMO
BACKGROUND: Stavudine, a nucleoside reverse transcriptase inhibitor, is used commonly to treat HIV-infected children in the developing world. The paediatric liquid formulation presents major logistical difficulties in rural and resource-limited areas, and prescribers are frequently forced to employ off-label 'opened capsule' dosing methods using the adult capsule. The South African Department of Health (DoH) has advised that caregivers should be instructed to disperse the contents of an adult capsule in 5 ml water and then withdraw the required dose using a syringe. The bioavailability of stavudine using the opened capsule dosing method has not previously been validated. METHODS: This was a randomized crossover pharmacokinetic study with each subject serving as his/her own control. A total of 28 healthy HIV-negative adult volunteers were randomized on a 1:1 basis to receive one of the two generic preparations typically available in state hospitals. They were then further randomized to receive either intact or opened 30 mg capsules. After 1 week, those who initially received intact capsules, were given opened capsules and vice versa. The capsule dispersion technique used was identical to that prescribed by the DoH. Serial blood samples were collected and plasma stavudine concentrations were assayed by liquid chromatography tandem mass spectrometry. Stavudine pharmacokinetics were analysed using non-compartmental methods and formulations were compared using ANOVA. RESULTS: Plasma drug exposure after stavudine administration as a solution using an opened capsule dosing method was found to be bioequivalent to intact capsule administration. This was true for both generics tested. CONCLUSIONS: The opened capsule dosing technique is bioequivalent to intact capsule dosing for stavudine in HIV-seronegative adults.
Assuntos
Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/farmacocinética , Infecções por HIV/tratamento farmacológico , Inibidores da Transcriptase Reversa/administração & dosagem , Estavudina/administração & dosagem , Estavudina/farmacocinética , Administração Oral , Adulto , Fármacos Anti-HIV/sangue , Cápsulas , Cromatografia Líquida , Estudos Cross-Over , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Uso Off-Label , Inibidores da Transcriptase Reversa/sangue , Inibidores da Transcriptase Reversa/farmacocinética , Estavudina/sangue , Espectrometria de Massas em Tandem , Equivalência TerapêuticaRESUMO
In the present work, a single model-independent approach was developed to optimize the release kinetics of drugs from sustained-release formulations, using stavudine (d4T) as a model drug. This approach is based on the pharmacokinetic simulation of drug plasma levels through a semiparametric approach of the input function and on convolution with an empirical polyexponential unit impulse response function. Input functions were evaluated using different zero-order and first-order release constants. Optimum drug release to obtain a specific pharmacokinetic profile was approached using target model-independent pharmacokinetic parameters such as C(max)(SS), C(min)(SS), t(max)(SS), and peak-trough fluctuations. A Monte Carlo simulation was performed to estimate the fractional attainment of d4T plasma concentrations over therapeutic d4T levels. Zero-order (K(0) = 4 mg/h) and first-order (K(1) = 0.05 h(-1)) release constants were optimal for the formulation of sustained-release d4T tablets, plasma concentrations within the therapeutic range being achieved.
Assuntos
Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Modelos Biológicos , Modelos Químicos , Química Farmacêutica , Simulação por Computador , Humanos , Cinética , Método de Monte Carlo , Solubilidade , Estavudina/sangue , Estavudina/química , Estavudina/farmacocinética , ComprimidosRESUMO
A high performance liquid chromatographic method with UV detection was developed and validated for simultaneous determination of stavudine and lamivudine in human plasma using solid-phase extraction for sample clean-up. Zidovudine was used as an internal standard. Separation was performed on a C18 column by gradient elution with a mobile phase of 10 mM acetate buffer pH 6.5 and acetonitrile. The UV detection was set at 265 nm. The method proved to be specific, accurate, precise and linear over the concentration ranges of 50-3000 ng/ml for stavudine and 50-5000 ng/ml for lamivudine with correlation coefficients always > 0.996 for both drugs. The intra-day and inter-day precision and accuracy were less than 9.2% for both analytes. The absolute recoveries of both compounds ranged from 93.3 to 97.5%. The method was successfully applied to a bioavailability study of a combined tablet formulation containing 30 mg of stavudine and 150 mg of lamivudine compared with each reference formulation concurrently administered in 26 healthy Thai male volunteers.
Assuntos
Fármacos Anti-HIV/sangue , Cromatografia Líquida de Alta Pressão/métodos , Lamivudina/sangue , Estavudina/sangue , Disponibilidade Biológica , Estabilidade de Medicamentos , Humanos , Padrões de Referência , Zidovudina/sangueRESUMO
BACKGROUND: Children remain under-represented in national antiretroviral treatment (ART) programmes in settings with limited resources and high HIV prevalence. In Malawi, an increasing number of HIV-infected children have been started on ART with split tablets of an adult fixed-dose combination drug in the past few years. In 2006, the national paediatric ART regime was changed from Triomune 40 (T40) to Triomune 30 (T30). METHODS: This was a cross-sectional study conducted at the paediatric ART clinic in Blantyre (Malawi) from September 2006 to July 2007. Children taking T30 for > 6 weeks from each dosing weight band (<5, 5-<8, 8-<12, 12-<14, 14-<19, 19-<26, 26-<30 and > or = 30 kg) were recruited. Plasma drug concentration, CD4+ T-cell count and HIV viral load were measured. RESULTS: A total of 74 children were analysed. The median nevirapine (NVP) concentration was 7.35 mg/l. A therapeutic NVP plasma level > 3 mg/l was found in 62 (87.8%) children. A subtherapeutic NVP level (< 3 mg/l) occurred significantly more often in children treated with T30 doses between one-quarter tablet once daily and one-half tablet twice daily (P=0.035). Median prescribed NVP dose was 342 mg/m(2)/day, but 13 (17.6%) children received a dose below the recommended dose of 300 mg/m(2)/day. Compared with a historical control, the median prescribed NVP dose was increased (from 243 to 342 mg/m(2)/day). CONCLUSIONS: Our findings indicate that with the Malawian T30-based ART regime, the majority (87.8%) of children in the study group achieved a therapeutic NVP level. However, treatment remains suboptimal especially for young children receiving T30 dosages less than or equal to one-half tablets twice daily and child appropriate formulations are warranted.
Assuntos
Fármacos Anti-HIV/sangue , Infecções por HIV/tratamento farmacológico , Lamivudina/sangue , Nevirapina/sangue , Estavudina/sangue , Comprimidos , Adolescente , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/uso terapêutico , Contagem de Linfócito CD4 , Criança , Pré-Escolar , Estudos Transversais , Formas de Dosagem , Esquema de Medicação , Combinação de Medicamentos , Feminino , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/fisiologia , Humanos , Lactente , Lamivudina/administração & dosagem , Lamivudina/uso terapêutico , Malaui , Masculino , Nevirapina/administração & dosagem , Nevirapina/uso terapêutico , Estavudina/administração & dosagem , Estavudina/uso terapêutico , Comprimidos/administração & dosagem , Comprimidos/uso terapêutico , Resultado do Tratamento , Carga ViralRESUMO
A new high-throughput LC-MS/MS method for the simultaneous determination of lamivudine (3TC), stavudine (d4T) and nevirapine (NVP) in human plasma is presented, with zidovudine as an internal standard. The analytes were extracted from plasma by protein precipitation and only 150 microL plasma was needed. Chromatographic separation was achieved on a Shiseido C(8) column (150 x 2.0 mm, 5 microm) with a total run time of 6 min. A tandem mass spectrometric detection was conducted using multiple reaction monitoring under positive ionization mode with an electrospray ionization interface. The method was developed and validated over the concentration range of 25-5000 ng/mL for 3TC and NVP and 20-4000 ng/mL for d4T. The method was validated in terms of intra- and inter-day precision (< or = 8.6%), accuracy (within +/- 8.4%), linearity and specificity. The method has been successfully applied to the pharmacokinetic study of a combination treatment of 300 mg lamivudine, 30 mg stavudine and 200 mg nevirapine in 22 healthy male volunteers under fasting conditions.
Assuntos
Cromatografia Líquida/métodos , Lamivudina/sangue , Lamivudina/farmacocinética , Nevirapina/sangue , Nevirapina/farmacocinética , Estavudina/sangue , Estavudina/farmacocinética , Espectrometria de Massas em Tandem/métodos , Humanos , MasculinoRESUMO
BACKGROUND & OBJECTIVES: Antiretroviral drug concentrations are important determinants of clinical response to a drug accounting for both toxicity and efficacy. Several factors such as age, ethnicity, body weight and patients' immune status may influence antiretroviral drug concentrations. The aim of the study was to determine the influence of immunological status, sex and body mass index on the steady state pharmacokinetics of lamivudine (3TC) and stavudine (d4T) in HIV-infected adults, who were undergoing treatment with generic fixed dose combinations (FDC) of these drugs in India. METHODS: Twenty seven HIV-1 infected patients receiving antiretroviral treatment (ART) for at least two weeks at the Government ART clinic at Tambaram, Chennai, took part in the study. Serial blood samples were collected predosing and at different time points after drug administration. Plasma 3TC and d4T levels were estimated by HPLC. RESULTS: The patients' immune status, sex or body mass index had no impact on the pharmacokinetics of 3TC. In the case of d4T, peak concentration was significantly lower in patients with CD4 cell counts < 200 cells/microl than those with > or = 200 cells/ microl (P < 0.05), but were within the therapeutic range. The mean CD4 cell counts increased from 101 cells/microl at initiation of ART to 366 cells/microl at 12 months of treatment. INTERPRETATION & CONCLUSIONS: Blood levels of 3TC and d4T drugs that are part of generic FDCs commonly used by HIV-infected individuals in India were within the therapeutic range and not influenced by nutritional or immune status. There was a significant improvement in CD4 cell counts over 12 months of treatment. Indian generic FDCs manufactured and used widely in the developing world provide effective concentrations of antiretroviral drugs.
Assuntos
Fármacos Anti-HIV , Combinação de Medicamentos , Infecções por HIV/tratamento farmacológico , HIV-1 , Lamivudina , Estavudina , Adulto , Fármacos Anti-HIV/sangue , Fármacos Anti-HIV/farmacocinética , Fármacos Anti-HIV/uso terapêutico , Feminino , Infecções por HIV/sangue , Humanos , Índia , Lamivudina/sangue , Lamivudina/farmacocinética , Lamivudina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Gravidez , Estavudina/sangue , Estavudina/farmacocinética , Estavudina/uso terapêuticoRESUMO
BACKGROUND: Nevirapine (NVP) plasma levels are reduced in patients receiving rifampicin (RFM) for tuberculosis (TB) treatment. We determined variations over time of the pharmacokinetic parameters of NVP in patients who receive RFM. METHODS: HIV-1-infected patients with CD4+ T-lymphocyte count Assuntos
Fármacos Anti-HIV/sangue
, Antibióticos Antituberculose/administração & dosagem
, Infecções por HIV/tratamento farmacológico
, HIV-1
, Nevirapina/sangue
, Rifampina/administração & dosagem
, Tuberculose/tratamento farmacológico
, Adulto
, Fármacos Anti-HIV/farmacocinética
, Fármacos Anti-HIV/uso terapêutico
, Contagem de Linfócito CD4
, Feminino
, Seguimentos
, Infecções por HIV/sangue
, Infecções por HIV/complicações
, Humanos
, Lamivudina/sangue
, Lamivudina/farmacocinética
, Lamivudina/uso terapêutico
, Estudos Longitudinais
, Masculino
, Pessoa de Meia-Idade
, Nevirapina/farmacocinética
, Nevirapina/uso terapêutico
, Estudos Prospectivos
, Estavudina/sangue
, Estavudina/farmacocinética
, Estavudina/uso terapêutico
, Tuberculose/complicações
RESUMO
A molecularly imprinted polymer (MIP) using zidovudine (AZT) as template and methacrylic acid as monomer was prepared. The synthesis of the MIP was performed in acetonitrile. The synthesized material was then tested for the solid-phase extraction of AZT from different media (pure organic solvents and hydro-organic mixtures). An optimised procedure was developed for the selective extraction of AZT with a recovery of 96% using the MIP and only 3% on a non-imprinted polymer used as control polymer. A specific capacity of 0.2 micromol g(-1) was determined. The specificity of the MIP was evaluated by studying the retention behaviour of two others nucleoside analogues. The feasibility of the MIP to selectively extract AZT and stavudine (d4T) from human serum was also demonstrated with recoveries of 80 and 85% respectively. The lower limit of quantification (LLOQ) and the lower limits of detection (LLOD) for AZT were 5.10(-7) and 10(-7) M respectively.
Assuntos
Fármacos Anti-HIV/sangue , Estavudina/sangue , Zidovudina/sangue , Cromatografia Líquida de Alta Pressão , Reações Cruzadas , Humanos , Indicadores e Reagentes , Espectrometria de Massas , Polímeros/química , SolventesRESUMO
OBJECTIVES: The objective of this study was to determine the correlation between plasma stavudine concentrations and lipoatrophy (LA), one of the major adverse events in patients on stavudine and one of the major reasons to discontinue stavudine. METHODS: Plasma drug concentrations were retrospectively analysed in patients who were on a stavudine-containing regimen for at least 12 months. We defined two groups of patients: 21 patients with LA and 15 patients without LA or other stavudine-related side effects (i.e. neuropathy). RESULTS: We analysed stavudine concentrations in 212 plasma samples: 87 in the control group and 125 in the LA group, with a mean of four plasma samples per person (at least two a year). Demographics were comparable in LA patients and controls, except the duration of stavudine use, which was longer in the LA group: 55 versus 42 months in the control group. Overall, LA patients had higher drug exposure to stavudine when compared with the controls, and this was seen in the geometric concentration ratios (CRs), which were 0.978 and 0.741, respectively (P = 0.04), and also a higher percentage of CR values >1.0, representing a drug concentration above the normal population curve (46% versus 23%, P = 0.02). In addition, the duration of stavudine therapy was independently associated with LA (P = 0.05). In the multivariate analysis, both duration of stavudine (P = 0.05) and CR > 1.0 (P = 0.02) were independently correlated with LA. CONCLUSIONS: Monitoring of plasma stavudine concentrations can be useful to prevent stavudine-related LA.
Assuntos
Infecções por HIV/tratamento farmacológico , Lipodistrofia/induzido quimicamente , Plasma/química , Estavudina/efeitos adversos , Estavudina/sangue , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Retrospectivos , Estavudina/uso terapêutico , Fatores de TempoRESUMO
The interest in therapeutic drug monitoring (TDM) of antiretroviral drugs has grown significantly since highly active antiretroviral therapy (HAART) became a standard of care in clinical practice. TDM is useful to determine the best dosage regimen adapted to each patient. Here, we apply MALDI-TOF/TOF technology to quantify abacavir, amprenavir, didanosine, efavirenz, nevirapine, and stavudine in the plasma of HIV-infected patients, by standard additions analysis. Regression of standard additions was linear over the whole anti-HIV concentration range explored (1.00 x 10(-2)-1.00 pmol/microL). The absolute recovery ranged between 80% and 110%. Values of the drug concentration determined by MALDI-TOF/TOF were in the range of 1.00 x 10(-2)-1.00 pmol/microL. The limit of quantification value was 1.00 x 10(-2)pmol/microL for abacavir, amprenavir, didanosine, efavirenz, nevirapine, and stavudine.
Assuntos
Fármacos Anti-HIV/sangue , Monitoramento de Medicamentos/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Alcinos , Fármacos Anti-HIV/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Benzoxazinas/sangue , Carbamatos/sangue , Ciclopropanos , Didanosina/sangue , Didesoxinucleosídeos/sangue , Estudos de Viabilidade , Furanos , Humanos , Estrutura Molecular , Nevirapina/sangue , Inibidores da Transcriptase Reversa/sangue , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta , Estavudina/sangue , Sulfonamidas/sangueRESUMO
Early failures to stavudine/lamivudine/nevirapine used as a generic fixed-dose combination in Mali showed resistance mutations in 50% of cases (mostly M184V and Y181C). No thymidine analogue mutations were seen, suggesting that most nucleoside reverse transcriptase inhibitors could be used in a second-line regimen. This highlights the importance of the accessibility of HIV-RNA assays for monitoring treated patients in resource-poor countries to detect early virological failure in order to preserve future therapeutic options.
Assuntos
Países em Desenvolvimento , Farmacorresistência Viral Múltipla , Infecções por HIV/tratamento farmacológico , HIV-1/fisiologia , Inibidores da Transcriptase Reversa/uso terapêutico , Adulto , Combinação de Medicamentos , Medicamentos Genéricos , Feminino , Genes MDR , Infecções por HIV/sangue , Infecções por HIV/imunologia , HIV-1/genética , Humanos , Lamivudina/sangue , Lamivudina/uso terapêutico , Masculino , Mali , Mutação , Nevirapina/sangue , Nevirapina/uso terapêutico , RNA Viral/sangue , Estavudina/sangue , Estavudina/uso terapêutico , Falha de Tratamento , Carga ViralRESUMO
OBJECTIVE: Simple methods for the determination of zidovudine (AZT), stavudine (d4T), lamivudine (3TC) and indinavir (INV) in human plasma by reversed-phase liquid chromatography (HPLC) with UV detection were described and validated. METHOD: Solid-liquid extraction procedures were applied to the samples prior to analysis. Chromatography was performed on a C-18 analytical columns and the retention time ranged from 6.8 to 8.0 min for stavudine, 7.5 to 9.0 min for lamivudine, 11.2 to 11.9 min for zidovudine and indinavir. Four methods were validated for specificity, inter-and intra-assay precision and accuracy, absolute recovery and stability. RESULTS: Analytical curve ranged from 10-1600 ng/ml for stavudine, 50-3200 ng/ml for lamivudine, 0.05-5.0 microg/ml for zidovudine and 0.1-10.0 microg/ml for indinavir. Analytes stability during sampling processing and storage were established. Extraction recoveries are higher than 89% for all formulations. CONCLUSIONS: These methods proved to be simple, accurate and precise, and are currently in use in our laboratory for the quantitative analysis of antiretrovirals products in plasma, and for further pharmacokinetics and bioequivalence studies.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Indinavir/sangue , Lamivudina/sangue , Estavudina/sangue , Zidovudina/sangue , HumanosRESUMO
BACKGROUND: Intracellular nucleoside reverse transcriptase inhibitor triphosphate (NRTI-TP) concentrations are crucial in suppressing HIV replication. Little is known about how commonly used dual-NRTI regimens affect the intracellular levels of NRTI-TPs, the active form of these drugs. This study investigates the effect of dual-NRTI therapy in intracellular NRTI-TP levels. METHODS: NRTI and NRTI-TP concentrations were evaluated in HIV-infected patients receiving either lamivudine (3TC) and stavudine (d4T) or lamivudine with zidovudine (ZDV); NRTI and NRTI-TP concentrations were determined using a validated HPLC/MS/MS method. Plasma HIV-1 RNA levels were determined at baseline and monthly to examine the relationship between NRTI-TP concentrations and plasma HIV-1 RNA. RESULTS: Forty-one subjects completed the study. 3TC-TP significantly increased between day 1 and week 28 from 1.48 to 5.00 pmol/10(6) peripheral blood mononuclear cells (PBMC; P < 0.0001). NRTI-TP concentrations for d4T and ZDV did not significantly increase, with values at week 28 of 0.011 and 0.02 pmol/10(6) PBMC, respectively. Mean NRTI-TP/plasma ratios were 3%, 0.007% and 0.05% for 3TC, d4T and ZDV, respectively. Linear relationships were observed between ZDV- and 3TC-TP and changes in plasma HIV-1 RNA. CONCLUSION: Of the three drugs studied, only 3TC-TP levels increased significantly between day 1 and week 28. ZDV-TP and 3TC-TP levels were unaffected by dual-NRTI therapy relative to monotherapy, regardless of the combination (3TC-ZDV or 3TC-d4T). Intracellular levels of d4T-TP were similar to previous reports for dual-NRTI therapy; however, in the case of d4T, these values appear lower than those achieved with d4T monotherapy.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Citidina Trifosfato/análogos & derivados , Didesoxinucleotídeos/sangue , Infecções por HIV/tratamento farmacológico , Lamivudina/análogos & derivados , Inibidores da Transcriptase Reversa/uso terapêutico , Nucleotídeos de Timina/sangue , Zidovudina/análogos & derivados , Fármacos Anti-HIV/sangue , Citidina Trifosfato/sangue , Quimioterapia Combinada , Feminino , Infecções por HIV/sangue , Infecções por HIV/virologia , Humanos , Lamivudina/sangue , Lamivudina/uso terapêutico , Leucócitos Mononucleares/metabolismo , Masculino , Inibidores da Transcriptase Reversa/sangue , Estavudina/sangue , Estavudina/uso terapêutico , Zidovudina/sangue , Zidovudina/uso terapêuticoRESUMO
A selective and high throughput liquid chromatography/tandem mass spectrometry (LC-MS/MS) method has been developed and validated to separate, detect and simultaneously quantify lamivudine (3TC), stavudine (d4T) and nevirapine (NVP) in human plasma using metaxalone as internal standard (IS). After solid phase extraction (SPE), the analytes and the IS were chromatographed on a Symmetry C18 (150 mmx3.9 mm i.d., 5 microm particle size) column using 5 microL injection volume with a run time of 4.5 min. An isocratic mobile phase consisting of 0.5% glacial acetic acid in water:acetonitrile (20:80, v/v) was used to separate all these drugs. The precursor and product ions of these drugs were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring mode (MRM) without polarity switch. The method was validated over the range of 25-3000 ng/mL for 3TC, 20-2000 ng/mL for d4T and 50-5000 ng/mL for NVP. The absolute recoveries for analytes (>or=86%) and IS (98.12%) achieved from spiked plasma samples were consistent and reproducible. Inter-batch and intra-batch precision (%CV) across four validation runs (LLOQ, LQC, MQC and HQC) was less than 10. The accuracy determined at these levels was within +/-8% in terms of relative error. The method was successfully applied to a pivotal bioequivalence study of [60 (3TC)+12 (d4T)+100 (NVP)] mg dispersible tablets in 60 healthy human subjects under fasting condition.