Development and validation of RP-HPLC method for simultaneous determination of lamivudine, stavudine, and zidovudine in perfusate samples: Application to the Single-Pass Intestinal Perfusion (SPIP) studies

A reversed-phase high performance liquid chromatography (RP-HPLC) method with ultraviolet detection was developed and validated for the simultaneous quantification of antiretroviral drugs lamivudine (3TC), stavudine (d4T), and zidovudine (AZT) in perfusate samples obtained from the Single-Pass Intestinal Perfusion studies. The chromatographic analysis was performed using a Gemini C18 column and didanosine as internal standard (IS). The following parameters were considered for the validation procedure: system suitability, accuracy, precision, linearity and selectivity. The limits of detection were 0.32 µg/mL for 3TC, 0.11 µg/mL for d4T and 0.45 µg/mL for AZT and the limits of quantification were 1.06 µg/mL for 3TC, 0.38 µg/mL for d4T and 1.51 µg/mL for AZT. Repeatability and intermediate precision ranged from 1.05 to 1.31 and 1.50 to 1.87, respectively, and are expressed as percent of relative standard deviation (RSD). Based on these results, the developed and validated RP-HPLC method can be used for simultaneous determination of 3TC, d4T, and AZT in perfusate samples. Furthermore, this method is simple and adequate for measurements of the antiretroviral drugs in the same sample, since those compounds are mostly co-administered. Besides, this work can be used as an initial base for the development of similar methods in the same conditions presented in our study.

Novel fluoronucleoside analog NCC inhibits lamivudine-resistant hepatitis B virus in a hepatocyte model

ABSTRACT Antiviral drug resistance is the most important factor contributing to treatment failure using nucleos(t)ide analogs such as lamivudine for chronic infection with hepatitis B virus (HBV). Development of a system supporting efficient replication of clinically resistant HBV strains is imperative, and new antiviral drugs are needed urgently to prevent selection of drug-resistant HBV mutants. A novel fluorinated cytidine analog, NCC (N-cyclopropyl-4′-azido-2′-deoxy-2′-fluoro-β-d-cytidine), was recently shown to strongly inhibit human HBV in vitro and in vivo. This study was designed to evaluate the antiviral activity of NCC against lamivudine-resistant HBV. We generated a stable cell line encoding the major pattern of lamivudine-resistant mutations rtL180M/M204V and designated it "HepG2.RL1". Immuno-transmission electron microscopic examination and enzyme-linked immunosorbent assay were used to detect secretion of HBV-specific particles and antigens. Quantification of extracellular DNA and intracellular DNA of HepG2.RL1 cells by quantitative real-time polymerase chain reaction revealed >625-fold and >5556-fold increases in the 50% inhibitory concentration of lamivudine, respectively, compared with that for the wild-type virus. The results showed that NCC inhibited DNA replication and HBeAg production in wild-type or lamivudine-resistant HBV in a dose-dependent manner. In conclusion, screening for antiviral compounds active against lamivudine-resistant HBV can be carried out with relative ease using hepG2.RL1 cells. NCC is a potential antiviral agent against wild-type HBV and clinical lamivudine-resistant HBV and deserves evaluation for the treatment of HBV infection.

Desenvolvimento e caracterização de nanopartículas de poli (n-butil cianoacrilato) contendo a associação lamivudina e zidovudina / Development and characterization of poly (n- butyl cyanoacrylate) nanoparticles containing the combination of lamivudine and zidovudine

A zidovudina (AZT), fármaco antirretroviral utilizado no tratamento da AIDS, apresenta biodisponibilidade oral em torno de 60% e seu uso prolongado pode ocasionar efeitos tóxicos e tolerância ao tratamento. A lamivudina (3TC), apesar de demonstrar menor citotoxicidade e menor resistência viral, é considerada também menos potente. A associação entre os dois fármacos é recomendável em função da boa resposta terapêutica e maior adesão ao tratamento. As nanopartículas são uma alternativa para melhorar a biodisponibilidade e o transporte de fármacos sobretudo através da BHE. Nesse sentido, as nanopartículas poliméricas de poli (n-butil cianoacrilato) (PBCA) apresentam grande potencial para melhoria das características farmacêuticas, além de possibilitar resultados terapêuticos mais eficazes por meio da modificação de sua superfície, direcionando o fármaco ao sítio alvo. Diante do exposto, foram desenvolvidas nanopartículas de PBCA contendo a associação lamivudina e zidovudina (3TC/AZT) revestidas com polissorbato 80 (Ps80). As nanopartículas obtidas foram caracterizadas e apresentaram resultados coerentes aos encontrados na literatura. Após a encapsulação dos fármacos e o revestimento com Ps80, notou-se um aumento no diâmetro médio e o potencial Zeta foi próximo de zero. Esses resultados juntamente com a análise de SAXS comprovam o revestimento das nanopartículas de PBCA. Os dados de DSC e TG/DTG mostram que a encapsulação foi eficiente para a estabilização térmica dos fármacos. Foi desenvolvido e validado o método analítico por CLAE, a fim de determinar a eficiência de encapsulação. A validação do método analítico para quantificação simultânea do 3TC e AZT, tanto nas nanopartículas de PBCA quanto nas nanopartículas revestidas, apresentou linearidade, especificidade, precisão e exatidão adequadas de acordo com as normativas. A porcentagem de encapsulação dos fármacos foi igual a 44,45% e 30,44%. As nanopartículas de PBCA e PBCAPs80, em concentrações abaixo de 100 µg/mL, apresentaram viabilidade celular superior a 70% em células Caco-2, comprovando que o sistema apresenta baixa citotoxicidade, o que representa uma alternativa promissora para a encapsulação de fármacos antirretrovirais e consequente progresso no tratamento da AIDS

Zidovudine (AZT), which is an anti-retroviral drug used in the treatment of AIDS, has oral bioavailability around 60% and its prolonged use can cause toxic effects and tolerance to the treatment. Lamivudine (3TC), although it has lower cytotoxicity and lower viral resistance, is also considered less potent. The association between these two drugs is recommended based on the good therapeutic response and greater adherence to treatment. Nanoparticles are an alternative to improve the bioavailability and the transport of drugs, particularly through the BBB. Thus, the polymeric nanoparticles of poly (n-butyl cyanoacrylate) (PBCA) have great potential for improving the pharmaceutical characteristics, besides enabling more effective therapeutic results through the modification of its surface, directing the drug to the target site. That being said, PBCA nanoparticles were developed containing the association of lamivudine and zidovudine (3TC/AZT) coated with polysorbate 80 (Ps80). Nanoparticles obtained were characterized and presented coherent results when compared to those found in the literature. After the encapsulation of pharmaceuticals and Ps80 coating, it was noted an increase in the average diameter and Zeta potential was close to zero. These results along with the SAXS analysis proved the coating of the PBCA nanoparticles. The data of DSC and TG/DTG show that encapsulation was efficient for thermal stabilization of pharmaceuticals. An analytical method by HPLC was developed and validated to determine the efficiency of encapsulation. The validation of the analytical method for simultaneous quantification of 3TC and AZT, in both the PBCA nanoparticles and coated nanoparticles, presented as in linearity, specificity, precision and accuracy according to the regulations. The percentage of drug encapsulation was equal to 44.45% and 30.44%. The nanoparticles of PBCA and PBCA-Ps80, at concentrations below 100 µg/ml, presented cell viability greater than 70% in Caco-2 cells, proving that the system has low cytotoxicity, which represents a promising alternative for the encapsulation of antiretroviral drugs and consequent progress in AIDS treatment

Comparison of the clinical outcomes between antiviral-naïve patients treated with entecavir and lamivudine-resistant patients receiving adefovir add-on lamivudine combination treatment

BACKGROUND/AIMS: To analyze the effects of preexisting lamivudine (LAM) resistance and applying antiviral treatment (adefovir [ADV] add-on LAM combination treatment) on long-term treatment outcomes, and comparing the clinical outcomes of antiviral-naïve chronic hepatitis B patients receiving entecavir (ETV) monotherapy. METHODS: This study enrolled 73 antiviral-naïve patients who received 0.5-mg ETV as an initial therapy and 54 patients who received ADV add-on LAM combination treatment as a rescue therapy from July 2006 to July 2010. RESULTS: During 24-month treatments, the decreases in serum log10HBV-DNA values (copies/mL) were significantly greater in the antiviral-naïve patients treated with ETV than the patients receiving ADV add-on LAM combination treatment. The biochemical response rates for alanine aminotransferase normalization at 6 months (ETV) and 12 months (ADV add-on LAM) were 90.4% (66/73) and 77.8% (42/54), respectively (P=0.048). A Kaplan-Meier analysis indicated that the rates of serologic response, viral breakthrough, and emergence of genotypic resistance did not differ significantly between the two patient groups. There were also no significant intergroup differences in the rates of disease progression (PD) and new development of hepatocellular carcinoma (HCC). CONCLUSION: The long-term clinical outcomes of antiviral-naïve patients treated with ETV and LAM-resistant patients receiving ADV add-on LAM combination treatment were comparable in terms of the emergence of HCC and disease progression.

Simultaneous detection of hepatitis B virus genotypes and mutations associated with resistance to lamivudine, adefovir, and telbivudine by the polymerase chain reaction-ligase detection reaction

OBJECTIVES: Detection of mutations associated to nucleos(t)ide analogs and hepatitis B virus (HBV) genotyping are essential for monitoring treatment of HBV infection. We developed a multiplex polymerase chain reaction-ligase detection reaction (PCR-LDR) assay for the rapid detection of HBV genotypes and mutations associated with lamivudine, adefovir, and telbivudine resistance in HBV-infected patients. METHODS: HBV templates were amplified by PCR, followed by LDR and electrophoresis on a sequencer. The assay was evaluated using plasmids that contained wild-type or mutant HBV sequences and 216 clinical samples. RESULTS: The PCR-LDR assay and sequencing gave comparable results for 158 of the 216 samples (73.1 percent) with respect to mutation detection and genotyping. Complete agreement between the two methods was observed for all the samples (100 percent) at codon 180 and codon 204. Concordant results were observed for 99.4 percent of the 158 samples at codon 181 and 98.7 percent at codon 236. The genotyping results were completely concordant between the PCR-LDR assay and sequencing. The PCR-LDR assay could detect a proportion of 1 percent mutant plasmid in a background of wild-type plasmid. CONCLUSION: The PCR-LDR assay is sensitive and specific for detection of HBV genotypes and drug resistance mutations, and could be helpful for decision making in the treatment of HBV infection.

Evaluation of adefovir & lamivudine in chronic hepatitis B: correlation with HBV viral kinetic, hepatic-necro inflammation & fibrosis.

Background & objectives: Chronic hepatitis B is an important cause of morbidity and mortality. We conducted a study comparing the efficacy of adefovir and lamivudine with respect to their impact on serum and hepatic viral DNA clearance, and improvement in hepatic necro-inflammatory score, in naive patients of chronic hepatitis B. Methods: This prospective randomized pilot study was conducted in Lok Nayak Hospital, New Delhi, involving 30 patients of chronic hepatitis B (both e antigen positive and negative); 15 were randomly selected to receive either adefovir or lamivudine for a period of 6 months. Quantification of serum and hepatic HBV DNA levels was done by real time PCR and liver biopsy was done at the beginning and end of 6 months. Results: Serum ALT was elevated to 2 or more times normalized in both the groups. In the adefovir group, two patients became HBeAg negative. In the lamivudine group, one patient became HBeAg negative. After therapy HBV DNA was negative in 26.7 per cent patients from adefovir group and 13.3 per cent patients from lamivudine group. Serum HBV DNA levels were correlated with the hepatic levels before therapy (r=0.843; P<0.001) and after therapy (r=0.713, P<0.001) showing strong correlation. There was a median reduction of 1.92 and 2.06 log copies per ml in serum HBV DNA load after adefovir and lamivudine therapy, respectively. The mean reduction in the histotogy activity index (HAI) score was 2 and 1.53, fibrosis score was 2.33 and 3.06 after adefovir and lamivudine therapy respectively. Interpretation & conclusions: Adefovir and lamivudine treatment caused biochemical and serological improvement when administered for about 6 months with significant reduction in HBV DNA, serum and hepatic viral load without completely clearing the virus from either serum or liver. It also helped in reduction of the necro-inflammatory and fibrosis score of patients with chronic hepatitis B. Our study also showed significant correlation between serum and hepatic HBV DNA levels both before and after therapy. There was not enough evidence to show therapeutic advantage of one drug over the other in any of the parameters measured.

Análise morfológica e fisiológica dos fígados e rins de ratas prenhes e seus fetos tratados pela associação zidovudina, lamivudina e ritonavir durante toda a prenhez / Morphological and physiological analysis of livers and kidneys of pregnant rats and their fetuses treated by the association of zidovudine, lamivudine and ritonavir for the whole period of pregnancy

OBJETIVO: avaliar os efeitos da administração da associação zidovudina-lamivudina-ritonavir nos fígados e rins de ratas prenhes e seus conceptos do ponto de vista morfológico e fisiológico. MÉTODOS: 40 ratas albinas prenhes foram aleatoriamente divididas em 4 grupos: 1 controle (Ctrl: controle de veículo) e 3 experimentais (Exp1x, Exp3x e Exp9x). Estes últimos foram tratados por solução oral de zidovudina/lamivudina/ritonavir (Exp1x: 10/5/20 mg/kg; Exp3x: 30/15/60 mg/kg; Exp9x: 90/45/180 mg/kg). As drogas e o veículo foram administrados por gavagem, desde o 1º até o 20º dia de prenhez. No último dia do experimento, todos os animais foram anestesiados e sangue foi retirado da cavidade cardíaca para avaliação sérica das enzimas aspartato aminotransferase (AST) e alanina aminotransferase (ALT), por método calorimétrico, bem como da ureia, determinada por método cinético-enzimático, e creatinina, por método cinético-colorimétrico. Em seguida, fragmentos dos fígados e rins maternos e fetais foram coletados, fixados em formol a 10 por cento e processados segundo os métodos histológicos para inclusão em parafina. Cortes com 5 µm de espessura foram corados pela hematoxilina-eosina (HE) e analisados por microscopia de luz. Na leitura das lâminas, considerou-se o padrão de normalidade para fígado e rins, tais como: hepatócitos, espaço porta íntegros e veias hepáticas bem definidas. Nos rins, a presença de corpúsculos renais, túbulos contorcidos e alças de Henle típicos. Nos fígados fetais considerou-se, ainda, a morfologia das células da linhagem eritrocitária nas diferentes fases do desenvolvimento, bem como os megacariócitos. Quando houve alteração da coloração padrão estabelecida para as estruturas hepáticas e renais, alteração na morfologia de núcleos, rompimento de limites de alguma organela citoplasmática, presença de congestão vascular, tudo isso foi entendido como provavelmente provocado pelas drogas em sua(s) dose(s) de aplicação. A avaliação estatística foi realizada por análise de variância (ANOVA), completada pelo teste de Tukey-Kramer (p<0,05). RESULTADOS: os fígados maternos dos grupos Ctrl, Exp1x e Exp3x mostraram hepatócitos típicos, espaço porta íntegros e veias hepáticas com aspecto normal. No fígado materno do grupo Exp9x, foram encontrados hepatócitos com sinais de atrofia e apoptose (eosinofilia citoplasmática e núcleos picnóticos). Além disso, identificou-se vasodilatação dos capilares sinusoides (congestão). Os rins maternos dos grupos Ctrl e Exp1x apresentaram-se normais, com corpúsculos renais, túbulos contorcidos e alças de Henle típicos. Já nos grupos Exp3x e Exp9x, foram encontrados congestão vascular, glomérulos pequenos ricos em células contendo núcleos hipercromáticos, sendo mais intensos no Exp9x. Com relação aos fígados e rins fetais, não foram observadas alterações morfológicas ou fisiológicas nos grupos estudados. Encontrou-se aumento significante nos níveis da AST (305,70±55,80; p<0,05) e da creatinina (0,50±0,09; p<0,05) no grupo Exp9x. CONCLUSÕES: nossos resultados evidenciam que a administração da associação zidovudina/lamivudina/ritonavir a ratas prenhes em altas doses causa alterações morfológicas e funcionais nos fígados e rins maternos. Não houve alterações nem morfológicas nem fisiológicas nos fígados e rins fetais.

PURPOSE: to evaluate the effect of administration of three different doses of the zidovudine/lamivudine/ritonavir combination on the liver and kidneys of pregnant rats and their concepts from a morphological and physiological standpoint. METHODS: 40 pregnant EPM-1 Wistar rats were randomly divided into 4 groups: 1 control (Ctrl: drug vehicle control, n=10) and 3 experimental groups: Exp1x, Exp3x and Exp9x. An oral solution of the zidovudine/lamivudine/ritonavir combination was administered to the experimental groups from the day 0 to day 20 of pregnancy: Exp1x=10/5/20 mg/kg; Exp3x=30/15/60 mg/kg; Exp9x=90/45/180 mg/kg. On the 20th pregnancy day the rats were anesthetized and blood was taken directly from the ventricular chambers for further biochemical determinations: aspartate-(AST) and alanine-(ALT) aminotransferases (Calorimetric method), urea nitrogen (BUN) by an enzymatic-kinetic method, and creatinine by a kinetic-calorimetric method. Maternal and fetal liver and kidney samples were taken, fixed in 10 percent formaldehyde and processed histologically for paraffin embedding. Five µm-thick fragments of maternal and fetal livers and kidneys were stained with hematoxilyn-eosin, being analyzed by light microscopy. To interpret the results, the well-known pattern of normality for livers and kidneys was considered on the basis of the following structures: hepatocytes, portal structure, hepatic veins, renal corpuscles, renal tubules and loop of Henle. Regarding the fetal livers, we also considered the erythrocytes in their different stages of development as well as the megacariocytes. If there was a change in the established staining pattern for liver and kidney structures, changes in nuclear morphology, rupture of some cytoplasmic organelles, and presence of vascular congestion, this was considered to be due to the drug doses. Results were submitted to analysis of variance (ANOVA) and to the Tukey-Kramer multiple comparisons test (p<0.05). RESULTS: no morphological changes were observed in the maternal livers of the Ctrl, Exp1x and Exp3x groups. In the maternal liver of the Exp9x group, hepatocytes showed signs of atrophy and apoptosis (eosinophilic cytoplasm and pycnotic nuclei) and marked sinusoid capillary vasodilation (congestion) was observed. The maternal kidneys of the Ctrl and Exp1x groups were normal, with renal corpuscles, convoluted tubules and typical loops of Henle. In contrast, the Exp3x and Exp9x groups showed vascular congestion and small glomeruli rich in cells containing hyperchromatic nuclei which were more intense in Exp9x. Regarding the fetal organs, no morphological or physiological changes were observed. A significant increase of AST (305.70±55.80, p<0.05) and creatinine (0.50±0.09, p<0.05) was observed in group Exp9x. CONCLUSIONS: our results show that the administration of the zidovudine, lamivudine and ritonavir combination to pregnant rats at high doses caused morphological and physiological changes in the maternal liver and kidneys. On the other hand, there were no changes in fetal organs.

Clinical Outcomes of Lamivudine Therapy in HBeAg Positive Chronic Hepatitis B with Minimally Elevated ALT / 대한간학회지

BACKGROUND/AIMS: The aim of this study was to compare the efficacy of lamivudine therapy between chronic hepatitis B (CHB) patients, whose ALT levels less than 2 times the upper limit of normal (ULN) and patients whose ALT levels are more than 2 times ULN. METHODS: We retrospectively analyzed 508 consecutive patients with HBeAg-positive CHB who were treated with lamivudine for 1 year or more. Forty-six patients (Group A) with pretreatment ALT levels less than 2 times ULN were retrospectively compared with 462 patients (Group B) whose ALT levels are more than 2 times ULN. RESULTS: HBeAg seroconversion was achieved in 15 (32.6%) of group A and 162 (35.1%) of group B. The cumulative rates of HBeAg seroconversion in group A and B were 19% and 21% at 12 months; 35% and 31% at 24 months; and 38% and 39% at 36 months, respectively. HBV breakthrough was observed in 20 (43.5%) of group A and 192 (41.6%) of group B. The cumulative breakthrough rates of group A and B were 18% and 12% at 12 months; 33% and 29 % at 18 months; 45% and 42% at 24 months, respectively. Post-treatment relapse in group A and B occurred in 56% (5/9) and 41% (44/108), respectively. Therefore, the rates of the HBeAg seroconversion, breakthrough, and post-treatment relapse were not significantly different between these two groups. CONCLUSIONS: Lamivudine therapy in HBeAg-positive CHB patients whose ALT levels are minimally elevated is as effective as in treatment of the patients whose pretreated ALT levels are twice more than ULN.

Incidence of lamivudine resistance associated mutations in pol-gene of HIV-1 in patients from north India: a preliminary report.

Screening of drug-resistant variants is very important for the effective clinical management of HIV-infected patients and development of new strategies. The present study was aimed to detect codon-184 mutations in the pol-gene of HIV leading to resistance to lamivudine (3-TC) by nested cum ARMS-PCR approach in 10 treated and 9 treatment naive patients. For correlation the whole blood CD4/CD8 cell counts and the soluble TNFRII levels in plasma were also determined. Of the 19 patients tested, mutant variants were observed in 2 patients (Met Val in one and Met Val & lle in second) both being treated with 3-TC. No mutations were detected in the treatment-naive patients. The results confirmed that, drug resistant variants of codon-184 emerge rapidly in patients receiving 3-TC containing regimens including our population, which is mainly infected with subtypeC of the virus that could be detected along with wild viral population using sensitive approaches such as ARMS-PCR.

A comparative study on effect of lamivudine in wild and precore mutant variety of chronic hepatitis B virus infected patients.

The aim of this study is to evaluate the effectiveness of lamivudine treatment in both precore mutant and wild type of chronic hepatitis B (CHB) patients. The study was done on sixty CHB patients of both sexes seeking treatment in the Outpatient Department and admitted patients of Mymensingh Medical College Hospital. The patients were divided into two groups. Group A included chronic hepatitis B patients with raised ALT (> 80 u/l ) with HBeAg positivity, and group B included precore mutant variety of CHB patients with raised ALT (> 80 u/l) with HBeAg negativity. In Group-A, after 1 year of completion of lamivudine therapy there was 86.67% normalization of ALT, 23.33% HBeAg loss, 16.67% anti-HBeAg development and 73.33% HBV DNA loss. In Group-B, there was 76.67% normalization of ALT and 73.33% HBV DNA loss after 1 year of completion of therapy. In the present study, it was observed that lamivudine is equally effective in both wild and precore mutant variety of CHB patients. This was reflected by normalization of ALT and loss of HBV DNA. This study also shows the reappearance of HBV DNA during the later half of Lamivudine therapy which is due to YMDD mutation.