Optimization and Quest of HPMC loaded Stavudine Controlled Release Dosage Development by Central Composite Design utilizing Reduced Factorial Screening Technique

Abstract The current research focused on screening and finding the significant independent variables in stavudine loaded tablet, followed by optimizing the best formulation using central composite design. The objective of the study to develop stavudine loaded controlled release tablet utilizing reduced factorial design, followed by optimization technique as well as characterization of prepared tablets. Preliminary trial batches were prepared using different grades of hydroxypropyl methylcellulose. The resolution-IV reduced factorial design was selected to screen the significant independent variables in the dosage form design. A total number of eight runs were prepared and responses were recorded. The signified factors identified by half-normal and Pareto chart. The prepared tablets are evaluated for various physiochemical characterizations. Three dependent responses such as hardness, dissolution at 6 hour and 12 hours are considered in optimization process. Later on, drug-polymer interaction study was carried out. The principal of the study design based on finding the best formulation with prefixed set parameter values utilizing the concept of screening technique. It observed that HPMC K15M (57.18 %), HPMC K100 (66.32 %) and PVP K30 (7.97 %) as best composition in a formulation batch would fulfill the predetermined parameter with specific values.

Incidence and associated factors of type 2 diabetes mellitus onset in the Brazilian HIV/AIDS cohort study

ABSTRACT Background: People living with HIV (PLH) under combined antiretroviral therapy (cART) are at risk of developing type 2 diabetes mellitus (T2DM). Objective: We examined the incidence of T2DM, associated factors and mean time to outcome in PLH under cART. Method: Data for this multicenter cohort study were obtained from PLH aged over 18, who started cART in 13 Brazilian sites from 2003 to 2013. Factors associated with incident T2DM were evaluated by Cox multiple regression models. Results: A total of 6724 patients (30,997.93 person-years) were followed from January 2003 to December 2016. A T2DM incidence rate of 17.3/1000 person-years (95%CI 15.8-18.8) was observed. Incidence of isolated hypertriglyceridemia and impaired fasting glucose (IFG) were 84.3 (95%CI 81.1-87.6) and 14.5/1000 person-years (95%CI 13.2-15.9), respectively. Mean time to T2DM onset was 10.5 years (95%CI 10.3-10.6). Variables associated with incident T2DM were age 40-50 [Hazard Ratio (HR) 1.7, 95%CI 1.4-2.1] and ≥ 50 years (HR 2.4, 95%CI 1.9-3.1); obesity (HR 2.1, 95%CI 1.6-2.8); abnormal triglyceride/HDL-cholesterol ratio (HR 1.8, 95%CI 1.51-2.2). IFG predicted T2DM (HR 2.6, 95%CI 1.7-2.5) and occurred on average 3.3 years before diabetes onset. Exposure to stavudine for ≥ 2 years was independently associated with incident T2DM [HR 1.6, 95%CI 1.0-2.2). Conclusion: Brazilian PLH under cART are at significant risk of developing T2DM and share risk factors for diabetes onset with the general population, such as older age, obesity, and having metabolic abnormalities at baseline. Moreover, stavudine use was independently associated with incident T2DM. Identifying PLH at a higher risk of T2DM can help caretakers trigger health promotion and establish specific targets for implementation of preventive measures.

Association between antiretrovirals and thyroid diseases: a cross-sectional study

Objective This study aims to estimate the prevalence of thyroid diseases and anti-TPO status. We searched for an association among presence of immune reconstitution and use of stavudine, didanosine and protease inhibitors with thyroid diseases. Materials and methods A cross-sectional study was performed to analyze the records of 117 HIV-infected patients who had their CD4+ cell count, viral load, anti-TPO, TSH and free T4 levels collected on the same day. Immune reconstitution was considered in those whose T CD4+ count was below 200 cells/mm3, but these values increased above 200 cells/mm3 after the use of antiretrovirals. The odds ratio obtained by a 2x2 contingency table and a chi-square test were used to measure the association between categorical variables. Results The prevalence of thyroid disease was 34.18%; of these, 4.34% were positive for anti-TPO. There was an association of risk between stavudine use and subclinical hypothyroidism (OR = 4.19, 95% CI: 1.29 to 13.59, X2 = 6.37, p = 0.01). Immune reconstitution achieved protection associated with thyroid disease that was near statistical significance OR = 0.45, 95% CI: 0.19 to 1.04, X2 = 3.55, p = 0.059. Conclusion The prevalence of thyroid disease in the sample studied was higher than what had been found in the literature, with a low positive anti-TPO frequency. The historical use of stavudine has an association of risk for the presence of subclinical hypothyroidism, and immune reconstitution has trends towards protection for the presence of thyroid diseases. .

Resultados de una intervencion de farmacovigilancia en pacientes con VIH/SIDA tratados con estavudina / Pharmacosurveillance regarding Colombian patients beingtreated with stavudine

Objetivos Dado que la estavudina se ha asociado a toxicidad acumulativa e irreversible, se pretendió reducir la aparición de resultados negativos asociados al uso de estavudina mediante la notificación del riesgo a diferentes responsables de la atención sanitaria de pacientes con VIH/SIDA en Colombia. Métodos A partir de la base de datos de dispensación de medicamentos de Audifarma S.A a unos 4,5 millones de personas, se identificaron todos los usuarios de estavudina, se notificó el riesgo a los prestadores del servicio de salud y se recomendó la sustitución por zidovudina o tenofovir. Resultados En 2010 se identificaron 1 410 pacientes en tratamiento antirretroviral, de los cuales 109 (7,5 %) recibían estavudina, distribuidos en 20 ciudades del país y atendidos por 19 instituciones diferentes. Tras la intervención se consiguió en 28 meses reducir su empleo en 94,6 %. El medicamento más empleado en la sustitución fue zidovudina. Discusión Se consiguió exitosamente reemplazar estavudina siguiendo las recomendaciones de la Organización Mundial de la Salud, con lo cual se puede evitar la aparición de lipodistrofia y neuropatía periférica asociada a su empleo.(AU)

Objectives Reducing the occurrence of negative stavudine use-associated outcomes by reporting such risk to doctors responsible for the care of HIV/AIDS patients in Colombia as stavudine has been associated with cumulative and irreversible toxicity. Methods All stavudine users were identified from Audifarma S.A. (drug suppliers) databases (covering about 4.5million people). The risk was then reported to health service providers and the substitution of stavudine for zidovudine or tenofovir was recommended. Results It was found that 1,410 patients registered in the afore mentioned databases were receiving antiretroviral therapy during 2010, of whom 109 (7.5 %) were receiving stavudine; these patients were living in 20 cities and being attended by 19 institutions. Stavudine use became reduced by 94.6 % during the 28 months following the intervention. Zidovudine was the most commonly used replacement drug. Discussion Stavudine was successfully replaced following World Health Organization recommendations aimed at preventing the occurrence of lipodystrophy and the peripheral neuropathy associated with its use.(AU)

The influence of long-term nucleotide reverse transcriptase inhibitors on lipids metabolism in HIV/AIDS patients / 中华内科杂志

Objective To evaluate the influence of long-term nucleotide reverse transcriptase inhibitors (NRTIs) on lipids metabolism in HIV/AIDS patients and correlating clinical factors.Methods A total of 118 HIV/AIDS patients were divided into 3 groups:untreated group (40 patients),highly active antiretroviral therapy(HAART) for 1-2 years group (37 patients) and HAART over 5 years group (41 patients),with 20 healthy individuals as the control group.Clinical lipodystrophy (LD) was defined as concordance between patient's report of change and physical examination.Fat mass (FM) was measured by dual-energy X-ray absorptiometry (DXA).Results There was no significant difference in the incidence of LD between HAART for 1-2 years group and HAART over 5 years group (51.2％ vs 40.5％,P =0.345).The prevalence of LD was 2.4 folds with strvudine (d4T) treatment compared with zidovudine (AZT)-containing regimens (61.6％ vs 23.5％,P =0.001).Based on DXA measurements,FM of total body and limbs were significantly lower in the HAART over 5 years group than that in the control group,the untreated group and the HAART for 1-2 years group (P ＜ 0.05).Trunk FM was significantly lower in the HAART over 5 years group than the untreated group and the HAART for 1-2 years group (P ＜ 0.05).FM of total body and trunk were significantly lower in patients without LD in the HAART over 5 years group than patients without LD in the HAART for 1-2 years group (P ＜ 0.05).FM was correlated positively with body weight and BMI.Limbs FM was correlated negatively with peripheral blood triglyceride concentration.Conclusions HIV/AIDS patients with NRTIs therapy have high prevalence of LD,which mainly occurs 1-2 years after therapy,and increases with d4T treatment compared with AZT-containing regimens.There was no significant difference in the incidence of LD between the HAART for 1-2 years group and the HAART over 5 years group.FM was significantly decreased after long-term HAART in the patients with or without LD.DXA can evaluate LD objectively and guide further clinical treatment.

Short-term exposure to stavudine results in neuron apoptosis, neurite shrink and down-regulated expression of thymidine kinase 2 / 中华传染病杂志

Objective To investigate the central neurotoxicity induced by nucleoside analog reverse transcriptase inhibitors (NRTIs)-stavudine (D4T).Methods Mouse primary cortical neurons were cultured and treated with different concentrations of stavudine.Neuron apoptosis was analyzed by calcein/acetomethoxy/propidium iodide (AM/PI) staining. Morphological change of neuron was confirmed by immunofluorescence.Mitochondrial DNA copies which were usually evaluated through Cycloxygenase 2 (COX-2) and thymidine kinase2 (TK2) mRNA were determined by real-time quantitative polymerase chain reaction.Chi-square test,student t test and Wilcoxon nonparameter test were used to analyze the data.Results Neuronal apoptosis observed in 50 μmol/L D4T treatment group was more significant than that in 0μmol/L D4T treatment group and 25 μmol/L D4T treatment group (51.3％±12.4％ vs 24.9％±8.2％ and 26.5％±10.6％,respectively; x2 =7.25 and 6.93,respectively; both P＜0.01).The average neurite numbers of each neuron were 11.2±3.6 in 0μmol/L D4T treatment group,8.6±2.8 in 25 μmol/L D4T treatment group and 4.3±2.4 in 50 μmol/L D4T treatment group.The difference was statistically significant between 25 μmol/L D4T treatment group and 0 μmol/L D4T treatment group (t=4.06,P＜0.01) and between 50 μmol/L D4T treatment group and 25 μmol/L D4T treatment group (t =4.35,P＜ 0.01). Furthermore,the average lengths of neuritis were (319.9±100.2) μm in 0 μmol/L D4T treatment group,(298.3±83.9) μm in 25 μmol/L D4T treatment group and (258.4±82.2) μm in 50 μmol/L D4T treatment group.The difference was statistically significant between 25 μmol/L D4T treatment group and 0 μmol/L D4T treatment group (t=4.58,P＜0.01) and between 50 μmol/L D4T treatment group and 25 μmol/L D4T treatment group (t=4.65,P＜0.01).TK2 mRNA expression dramatically decreased along with the increasing D4T concentration.The fold changes were 0.34 in 25 μmol/L D4T treatment group and 0.08 in 50 μmol/L D4T treatment group. The difference was statistically significant between 25 μmol/L D4T treatment group and 0μmol/L D4T treatment group (Z=- 3.28,P＜0.01) and between 50 μmol/L D4T treatment group and 25 μmol/L D4T treatment group (Z=-4.25,P＜0.01).Compared with 0μmol/L D4T treatment group,the relative fold changes of COX-2 copies were 1.01 in 25 μmol/L D4T treatment group and 1.12 in 50 μmol/L D4T treatment group.The differences were not significant among the three groups (Z=0.98 and 1.24,respectively; both P＞0.05).Conclsion It suggests that short-term exposure to D4T may result in neuron apoptosis,neurite shrink and down-regulated expression of TK2,but the level of mitochondrial DNA copies keeps stable.

Efeitos da administração diária da associação estavudina/nelfinavir sobre os fetos e placentas da rata albina / Effects of daily administration of a stavudine/nelfinavir association on the fetuses and placentas of female albino rats

OBJETIVO: avaliar o efeito da administração da associação estavudina/nelfinavir durante toda a prenhez da rata, avaliando seu peso e dos conceptos, bem como o número de implantações, fetos, placentas, reabsorções e mortalidades materna e fetal. MÉTODOS: quarenta ratas albinas EPM-1 Wistar, prenhes, foram aleatoriamente divididas em quatro grupos: GCtrl (controle do veículo) e três experimentais, ExpI, ExpII e ExpIII, que receberam, respectivamente, 1/40, 3/120 e 9/360 mg/kg por dia de estavudina/nelfinavir por via oral. As drogas e o veículo (água destilada) foram administrados por gavagem em duas tomadas diárias (12/12 horas), desde o dia 0 até o 20º dia da prenhez. No último dia do experimento, todos os animais foram anestesiados e eutanasiados. Foram avaliados a evolução do peso materno no 7º, 14º e 20º dias, número de fetos, placentas, implantações, reabsorções, óbitos intrauterinos, malformações maiores e o peso dos fetos e das placentas. A análise estatística foi realizada por análise de variância (ANOVA), complementada pelo teste de Kruskal-Wallis (p<0,05). RESULTADOS: em relação ao peso corporal das ratas, houve ganho gradual e progressivo durante o decorrer da prenhez em todos os grupos, sendo este ganho mais evidente no período final; porém não foram constatadas diferenças estatisticamente significantes entre eles. O número de fetos, placentas, implantações, assim como os pesos fetais e placentários também não mostraram diferenças estatisticamente significantes entre os grupos analisados. Não foram observadas, também nos grupos experimentais, reabsorções e malformações fetais maiores externas, no entanto, observamos entre o 8º e o 14º dias de gestação um caso de morte materna em cada grupo experimental. CONCLUSÕES: a administração da associação estavudina/nelfinavir não mostrou efeitos deletérios sobre os conceptos.

PURPOSE: to evaluate the effect of administration of a stavudine/nelfinavir combination on the rat pregnancy by assessing maternal and concepts weights, as well as the number of implantations, fetuses, placentas, resorptions and maternal and fetal mortality. METHODS: forty adult pregnant Wistar rats of the EPM-1 strain were randomly divided into four groups: control (GCtrl - drug vehicle control, n=10), and three experimental groups, which were treated with an oral solution of stavudine/nelfinavir (ExpI - 1/40 mg/kg b.w., n=10; ExpII - 3/120 mg/kg b.w., n=10; ExpIII - 9/360 mg/kg b.w., n=10) from day 0 to the 20th day of pregnancy. Maternal body weights were determined at the start of the experiment and on the 7th, 14th and the 20th day thereafter. At term (20th day) the rats were anesthetized and, upon laparotomy and hysterotomy, the number of implantations, resorptions, living fetuses, placentae and intrauterine deaths were recorded. The collected fetuses and placentae were weighed and the concepts were examined under a stereomicroscope for possible external malformations. Statistical analysis was performed by analysis of variance (ANOVA) complemented by the Kruskal-Wallis test (p<0.05). RESULTS: there was a progressive and gradual increase in body weight during the course of pregnancy in all groups, which was more evident in the final period, but with no significant difference between groups. The mean number of fetuses, placentas, implantations, and fetal and placental weights showed no significant differences between groups. Also, no resorptions or external malformations were found in the experimental groups. However, between the 8th and 14th days of gestation, there was one case of maternal mortality in each experimental group. CONCLUSIONS: the administration of a stavudine/nelfinavir combination had no deleterious effects on the concepts.

Comparison of HPLC & spectrophotometric methods for estimation of antiretroviral drug content in pharmaceutical products.

Background & objectives: Simple and reliable methods to estimate drugs in pharmaceutical products are needed. In most cases, antiretroviral drug estimations are performed using a HPLC method, requiring expensive equipment and trained technicians. A relatively simple and accurate method to estimate antiretroviral drugs in pharmaceutical preparations is by spectrophotometric method, which is cheap and simple to use as compared to HPLC. We undertook this study to standardise methods for estimation of nevirapine (NVP), lamivudine (3TC) and stavudine (d4T) in single tablets/capsules by HPLC and spectrophotometry and to compare the content of these drugs determined by both these methods. Methods: Twenty tablets/capsules of NVP, 3TC and d4T each were analysed for their drug content by HPLC and spectrophotometric methods. Suitably diluted drug solutions were run on HPLC fitted with a C18 column using UV detection at ambient temperature. The absorbance of the diluted drug solutions were read in a spectrophotometer at 300, 285 and 270 nm for NVP, 3TC and d4T respectively. Pure powders of the drugs were used to prepare calibration standards of known drug concentrations, which was set up with each assay. Results: The inter-day variation (%) of standards for NVP, 3TC and d4T ranged from 2.5 to 6.7, 2.1 to 7.7 and 6.2 to 7.7, respectively by HPLC. The corresponding values by spectrophotometric method were 2.7 to 4.7, 4.2 to 7.2 and 3.8 to 6.0. The per cent variation between the HPLC and spectrophotometric methods ranged from 0.45 to 4.49 per cent, 0 to 4.98 per cent and 0.35 to 8.73 per cent for NVP, 3TC and d4T, respectively. Conclusions: The contents of NVP, 3TC and d4T in the tablets estimated by HPLC and spectrophotometric methods were similar, and the variation in the amount of these drugs estimated by HPLC and spectrophotometric methods was below 10 per cent. This suggests that the spectrophotometric method is as accurate as the HPLC method for estimation of NVP, 3TC and d4T in tablet/capsule. Hence laboratories that do not have HPLC equipment can also undertake these drug estimations using spectrophotometer.

d4T: keep it or abandon it.

Stavudine is a nucleoside analogue used widely for first-line treatment of HIV in developing and middleincome countries. The World Health Organization recommended that all patients should switch to stavudine (30mg BID). However, there is evidence from the dose-ranging trials that patients with body weight below 60kg should use a dose of 20mg BID. For patients who show adverse events on stavudine, a switch to other nucleoside analogues can be considered. This article reviews d4T to study if it should be kept or abandoned.

Micronuclei induced by reverse transcriptase inhibitors in mononucleated and binucleated cells as assessed by the cytokinesis-block micronucleus assay

This study evaluated the clastogenic and/or aneugenic potential of three nucleoside reverse transcriptase inhibitors (zidovudine - AZT, lamivudine - 3TC and stavudine - d4T) using the cytokinesis-block micronucleus (CBMN) assay in human lymphocyte cultures. All three inhibitors produced a positive response when tested in binucleated cells. The genotoxicity of AZT and 3TC was restricted to binucleated cells since there was no significant increase in the frequency of micronuclei in mononucleated cells. This finding indicated that AZT and 3TC caused chromosomal breakage and that their genotoxicity was related to a clastogenic action. In addition to the positive response observed with d4T in binucleated cells, this drug also increased the frequency of micronuclei in mononucleated cells, indicating clastogenic and aneugenic actions. Since the structural differences between AZT and 3TC and AZT and d4T involve the 3' position in the 2'-deoxyribonucleoside and in an unsaturated 2',3',dideoxyribose, respectively, we suggest that an unsaturated 2', 3', dideoxyribose is responsible for the clastogenic and aneugenic actions of d4T.

Pharmacokinetics of lamivudine & stavudine in generic fixed-dose combinations in HIV-1 infected adults in India.

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/μl than those with ≥ 200 cells/ μl (P < 0.05), but were within the therapeutic range. The mean CD4 cell counts increased from 101 cells/μl at initiation of ART to 366 cells/μl 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.

A study of HIV-related lipodystrophy syndrome in 55 HIV-infected Chinese adult patients / 中华内科杂志

Objective To study the prevalence, clinical characteristics and risk factors of HIV-related lipodystrophy syndrome (HIV-LD) in our cohort of HIV-1 infected Chinese adults. Methods In a cross-sectional study, 55 HIV-infected patients were recruited from the HIV clinic of Peking Union Medical College Hospital; most of them were undergoing the first-class highly active antiretroviral therapy (HAART) of today in China. Lipoatrophy or lipohypertrophy was defined if there was concordance between the report of fat change and clinical examination of the participants. Whole body dual-energy X-ray absorptiometry (DEXA) scanning was performed. Results Prevalence of clinical body fat redistribution in the present study was 47.3%. Comparing with non-LD patients, HIV-LD patients had elder age and longer exposure to HAART(P<0.05). HAART exposure and stavudine(d4T) usage were two independent risk factors for HIV-LD. Conclusions HIV-related fat redistribution does exist in Chinese HIV population. Peripheral lipoatrophy occurs commonly in HIV-infected adults but is not associated with increased trunk fat. HAART exposure and especially d4T usage are independent risk factors for HIV-LD.

Sensitive and rapid titrimetric and spectrophotometric methods for the determination of stavudine in pharmaceuticals using bromate-bromide and three dyes

Four sensitive and rapid methods for the determination of stavudine (STV) in bulk drug and in dosage forms were developed and optimized. In titrimetry, aqueous solution of STV was treated with a known excess of bromate-bromide in HCl medium followed by estimation of unreacted bromine by iodometric back titration. Spectrophotometric methods involve the addition of a measured excess of bromate-bromide in HCl medium and subsequent estimation of the residual bromine by reacting with a fixed amount of methyl orange, indigocarmine or thymol blue followed by measurement of absorbance at 520 nm (method A), 610 nm (method B) or 550 nm (method C). In all the methods, the amount of bromate reacted corresponds to the amount of STV. Calculations in titrimetry were based on a 1:0.666 (STV:KBrO3) stoichiometry and the method was found to be applicable over 3.5-10 mg range. A linear increase in absorbance with concentration of STV was observed in the spectrophotometric methods, and the Beer's law was obeyed over the concentration ranges 0.125-1.75, 1-10 and 1-9.0 µg mL-1 STV for method A, method B and method C, respectively. The methods when applied to the determination of STV in tablets and capsules were found to give satisfactory results.

Este trabalho descreve quatro métodos rápidos e sensíveispara a determinação de estavudina (STV) na matéria-prima ou em produtos formulados. Soluções aquosas de STV podem ser tituladas tratando-as com excesso de bromato-brometo em meio ácido clorídrico, seguido da determinação iodimétrica de bromo em excesso. Métodos espectrofotométricos tambémenvolvem a adição de excesso de bromato-brometo à amostra, seguida da determinação de bromo residual por adição de uma quantidade fixa de alaranjado de metila, índigo-carmim ou azul de timol, e de medidas de absorbância nos comprimentos de onda apropriados: 520, 610 ou 550 nm. Em todos os métodos, a quantidade de bromato consumida corresponde à quantidade de STV e os resultados da sua aplicação à determinação de STV em comprimidos e cápsulas são satisfatórios.

Use of chloramine-T and two dyes in the sensitive determination of stavudine in pharmaceuticals

Three new methods are described for the assay of stavudine (STV) in bulk drug and in dosage forms using chloramine-T (CAT) and two dyes, methyl orange and indigocarmine, as reagents. Titrimetry involves treating STV with a measured excess of CAT in hydrochloric acid medium, and after the oxidation of STV is judged to be complete, the unreacted oxidant is determined iodometrically. Spectrophotometric methods entail the addition of a known excess of CAT to STV in hydrochloric acid medium followed by determination of residual oxidant by reacting with a fixed amount of either methyl orange and measuring the absorbance at 520 nm (Method A) or indigo carmine and measuring the absorbance at 610 nm (Method B). In all the methods, the amount of CAT reacted corresponds to the amount of STV. In titrimetric method, the reaction follows 1:1 stoichiometry (STV: CAT), and is applicable over the range 1.5-10 mg of STV. In spectrophotometric methods, the absorbance is found to increase linearly with concentration of STV. The systems obey Beer's law for 0.2-2.0 and 1.0-10.0 mg/mL for method A and method B, respectively. The apparent molar absorptivities are calculated to be 5.7x10(4) and 1.5x10(4) L/mol/cm for method A and method B, respectively, and the corresponding Sandell sensitivity values are 0.004 and 0.015 µg/cm². The limits of detection and quantification are reported for both methods. Intra-day and inter-day precision and accuracy of the developed methods were evaluated as per the current ICH guidelines. The methods were successfully applied to the assay of STV in tablet and capsule formulations and the results were compared with those of a reference method by applying Student's t-test and F-test. No interference was observed from common tablet adjuvants. The accuracy and reliability of the methods were further ascertained by performing recovery experiments via standard-addition method.

Descrevem-se três novos métodos para o ensaio de estavudina (STV) na matéria-prima e nas formulações utilizando-se clroamina-T (CAT) e dois corantes, alaranjado de metila e índigo carmim como reagentes. A titulação envolve o tratamento de STV com excesso medido de CAT em meio de ácido clorídrico, e, quando a oxidação se completar, o oxidante que não reagiu é determinado iodometricamente. Os métodos espectrofotométricos compreendem a adição de excesso conhecido de CAT ao STV em ácido clorídrico, seguida da determinação do oxidante residual por meio da reação com quantidade fixada de alaranjado de metila, medindo-se a absorvância a 520 nm (Método A) ou índigo carmim, medindo-se a absorvância a 610 nm (Método B). Em todos os métodos, a quantidade de CAT que reagiu corresponde à quantidade de STV. No método titulométrico, a reação segue a estequiometria 1:1 (STV:CAT) e é aplicável na faixa de 1,5 a 10 mg de STV. Nos métodos espectrofotométricos, a absorvância aumenta linearmente com a concentração de STV. Os sistemas obedecem a lei de Beer nos intervalos de 0,2 a 2,0 mg/mL e 1,0 a 10,00 mg/mL para os métodos A e B, respectivamente, e os valores de sensibilidade de Sandell correspondentes são 0,004 e 0,015 µg/cm². Os limites de detecção e de quantificação são apresentados para ambos os métodos. A precisão e a exatidão intra-dia e inter-dia dos métodos desenvolvidos são avaliadas de acordo com as normas ICH. Os métodos foram aplicados com êxito aos ensaios de STV em comprimidos e em cápsulas e os resultados foram comparáveis com aqueles obtidos com o método de referência, utilizando-se o teste t de Student e o teste F. Não se observou interferência dos adjuvantes comuns em comprimidos. A exatidão e a confiabilidade dos métodos foram ajustadas por meio de experimentos de recuperação via método de adição de padrão.

A Case of Lactic Acidosis Caused by Stavudine in an AIDS Patient

Nucleoside reverse transcriptase inhibitors (NRTIs), which are used for the treatment of human immunodeficiency virus (HIV) infection have been associated with a wide spectrum of clinical manifestations, including hepatic steatosis, lipodystrophy, myopathy, and lactic acidosis. Such adverse effects are postulated to result from the inhibition of mitochondrial DNA gamma polymerase, which causes the depletion of mitochondrial DNA and eventual the disruption of oxidative phosphorylation. Although cases of severe decompensated lactic acidosis are rare, this syndrome is associated with a high mortality rate. We report upon the first Korean case, of severe lactic acidosis in an acquired immunodeficiency syndrome (AIDS) patient receiving stavudine, an anti-HIV drug.

Determination of Stavudine and Related Substances by HPLC / 中国药房

OBJECTIVE:To establish a HPLC method for the determination of stavudine and related substances METHODS:The Hypersil C18(4 6mm?150mm,5?m)was used as analysis column The mobile phase was methanol-water(13∶87,V/V) Detection wavelength was 264nm The flow rate was 1ml/min The column temperature was 20℃ RESULTS:The calibration curves was linear in the concentration range of 0 025～0 3mg/ml(r=0 9 999,n=6) The average recovery was 99 26%(RSD=0 76%) The contents of stavudine in 3 batches of semifinished materials and stavudine capsules(imported and domestic)were 99 48%,99 55%,99 32%(materials);97 21%,101 54%,98 92%(imported stavudine capsule);100 57%,97 86%,102 33%(domestic stavudine capsule)respectively CONCLUSION:The method is simple,accurate,sensitive and repeatable and it is suitable for the determination of stavudine and its preparations

A Twenty Four Week Clinical Trial Using Didonosine, Stavudine and Nevirapine for Highly Active Antiretrioviral Therapy / 中国医师杂志

Objective To obserre antiviral effect, immune rebuilding efficacy and side effects of didonosine, stavudine and nevirapine combination therapy for human immunodeficiency virus (HIV) type 1 infection. Methods Three medicines were administered for 8 HIV-1 infected cases. Plasma HIV RNA load, and the levels of CD 4 + T cell and CD 8 + T cell were detected before starting treatment and 4,12 and 24 weeks after starting treatment. Side effects and changes in laboratory's examinations were observed during the trial. Results After 12 and 24 week treatment, the plasma HIV-1 level reduced 2 28 logs and 2 63 logs, from a mean baseline of (283,125?187,217) copies/ml to (1,501?930) copies/ml and (669?477) copies/ml, the CD 4 + T cell counts increased from a mean baseline of (337?221) cells/ml to (393?301) cells/ml and (414?284) cells/ml, and CD 8 + T cell counts decreased from a mean baseline of (918?371) cells/ml to (823?315) cells/ml (812?305) cells/ml, respectively. Part of cases occurred mild or medium rash, nausea, headache, fatique, abdomina1 pain and diarrhea, and had blood transaminase increased, and leucocyte and hemoglobin decreased. Conclusions Didonosine, stavudine and nevirapine showed high anti-HIV and immune rebuilding effects in highly active antiretroviral therapy (HAART). The medicine regimen was well tolerated in a six-month clinical trial.