[Short-term disability: surmounting conflict through understanding].
Explore the source record for details and available documents.
Humans↗
Biomedical subjects
L López-Lázaro
Publications and source records attributed to L López-Lázaro.
Switching from an analogous to a stable isotopically labeled internal standard for the LC-MS/MS quantitation of the novel anticancer drug Kahalalide F significantly improves assay performance.
The importance of a stable isotopically labeled (SIL) internal standard for the quantitative LC-MS/MS assay for Kahalalide F in human plasma is highlighted. Similar results can be expected for other LC-MS/MS assays. Therefore, we emphasize the need for an SIL internal standard for accurate and precise LC-MS/MS assays of drugs in biological matrices.
Antineoplastic Agents↗
Simple and sensitive liquid chromatographic quantitative analysis of the novel marine anticancer drug Yondelis (ET-743, trabectedin) in human plasma using column switching and tandem mass spectrometric detection.
The development of a simple and sensitive assay for the quantitative analysis of the marine anticancer agent Yondelis (ET-743, trabectedin) in human plasma using liquid chromatography (LC) with column switching and tandem mass spectrometric (MS/MS) detection is described. After protein precipitation with methanol, diluted extracts were injected on to a small LC column (10 x 3.0 mm i.d.) for on-line concentration and further clean-up of the sample. Next, the analyte and deuterated internal standard were back-flushed on to an analytical column for separation and subsequent detection in an API 2000 triple-quadrupole mass spectrometer. The lower limit of quantitation was 0.05 ng mL(-1) using 100 micro l of plasma with a linear dynamic range up to 2.5 ng ml(-1). Validation of the method was performed according to the most recent FDA guidelines for bioanalytical method validation. The time needed for off-line sample preparation has been reduced 10-fold compared with an existing LC/MS/MS method for ET-743 in human plasma, employing a labor-intensive solid-phase extraction procedure for sample pretreatment. The proposed column switching method was successfully applied in phase II clinical trials with Yondelis and pharmacokinetic monitoring.
Antineoplastic Agents, Alkylating↗
Quantitative analysis of ES-285, an investigational marine anticancer drug, in human, mouse, rat, and dog plasma using coupled liquid chromatography and tandem mass spectrometry.
A method was developed for the quantitative analysis of the novel anticancer agent ES-285 (spisulosine; free base) in human, mouse, rat, and dog plasma using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry in order to support pre-clinical and clinical studies with the drug. Sample preparation was carried out by protein precipitation with acetonitrile, containing isotopically labeled (d(3)) ES-285 as internal standard. Aliquots of 10 micro l of the supernatant were injected directly on to an Inertsil ODS-3 column (50 x 2.0 mm i.d., 5 micro m). Elution was carried out using methanol-10 mM ammonium formate (pH 4) in water (80 : 20, v/v) pumped at a flow-rate of 0.2 ml min(-1) with a run time of 8 min. Multiple reaction monitoring chromatograms obtained on an API365 triple-quadrupole mass spectrometer were used for quantification. The lower limit of quantitation (LLOQ) was 10 ng ml(-1) in human, mouse, rat, and dog plasma and the linear dynamic range extended to 500 ng ml(-1). A full validation of the method was performed in human plasma, and partial validations were performed in mouse, rat and dog plasma. Accuracies and precisions were <20% at the LLOQ concentration and <15% for all other concentrations in all matrices. ES-285 was stable during all steps of the assay. Thus far this method has been used successfully to analyze over 500 samples in pre-clinical trials, and will be implemented in the planned clinical phase I studies.
Alkanes↗
Yondelis (trabectedin, ET-743): the development of an anticancer agent of marine origin.
Yondelis (trabectedin, ET-743) is a novel antitumor agent derived from a marine source, the Caribbean tunicate Ecteinascidia turbinata. Preclinical studies demonstrated activity at low concentrations against a variety of tumors. The mechanism by which ET-743 exerts its antitumor activity has not been completely elucidated yet. Binding to the minor groove of DNA which causes a bend towards the major groove has been demonstrated. Furthermore, ET-743 interferes with DNA binding proteins and transcription factors. Clinical studies have been initiated as phase I dose-finding studies at four different treatment regimens. Dose-limiting toxicities were hematological, including neutropenia and thrombocytopenia. Furthermore, significant liver toxicity was observed, especially as a rise in transaminase levels. Antitumor activity in phase I and phase II trials was studied in multiple tumor types, including soft tissue sarcomas, melanomas and breast cancer. ET-743 is currently being extensively investigated in advanced soft tissue sarcomas. The present review describes the development of ET-743, highlighting chemical properties, mode of action, metabolism and preclinical and clinical studies.
Animals↗
Quantitative analysis of the novel depsipeptide anticancer drug Kahalalide F in human plasma by high-performance liquid chromatography under basic conditions coupled to electrospray ionization tandem mass spectrometry.
Kahalalide F (KF) is a novel cyclic depsipeptide anticancer drug, which has shown anticancer activity both in vitro and in vivo especially against human prostate cancer cell lines. To characterize the pharmacokinetics of KF during a phase I clinical trial in patients with androgen refractory prostate cancer, a method was developed and validated for the quantitative analysis of KF in human plasma using high-performance liquid chromatography (HPLC) coupled to positive electrospray ionization tandem mass spectrometry (ESI-MS/MS). Microbore reversed-phase liquid chromatography (LC) performed with mobile phases containing trifluoroacetic acid, an additive commonly used for separating peptides, resulted in substantial suppression of the signal for KF on ESI-MS/MS. An alternative approach employing a basic mobile phase provided an excellent response for KF when detected in the positive ion mode. Plasma samples were prepared for LC MS/MS by solid-phase extraction on C(18) cartridges. The LC separation was performed on a Zorbax Extend C(18) column (150 x 2.1 mm i.d., particle size 5 micro m) with acetonitrile -10 mM aqueous ammonia (85 : 15, v/v) as the mobile phase, at a flow-rate of 0.20 ml min(-1). A butyric acid analogue of KF was used as the internal standard. The lower limit of quantitation (LLQ) using a 500 micro l sample volume was 1 ng ml(-1) and the linear dynamic range extended to 1000 ng ml(-1). The inter-assay accuracy of the assay was -15.1% at the LLQ and between -2.68 and -9.05% for quality control solutions ranging in concentration from 2.24 to 715 ng ml(-1). The inter-assay precision was 9.91% or better at these concentrations. The analyte was stable in plasma under all relevant conditions evaluated and for a period of 16 h after reconstituting plasma extracts for LC analysis at ambient temperature.
Antineoplastic Agents↗
In vitro toxicity of ET-743 and aplidine, two marine-derived antineoplastics, on human bone marrow haematopoietic progenitors. comparison with the clinical results.
Ecteinascidine-743 (ET-743) and aplidine are two marine-derived antineoplastics currently in phase II development. With the aim of evaluating whether in vitro haematopoietic studies can predict the toxicity of these two drugs in patients, human bone marrow (BM) samples were incubated with these drugs under conditions which mimicked the administration exposures used in the clinics. As it was observed in different cancer cell lines, ET-743 was more toxic on an equimolar basis in human hematopoietic progenitors (inhibitory concentration reducing the viability to 50% after 24 h exposures; IC50(24h): 10-50 nM) compared with doxorubicin (IC50(24h) values: 280-460 nM), used as a control anticancer drug. In contrast to the high haematotoxic effects observed for ET-743, similar IC values were obtained for aplidine (IC50(24h): 150-530 nM) compared with doxorubicin. For both ET-743 and aplidine, the megakaryocytic progenitor was the most sensitive, compared with the other haematopoietic progenitors (IC50 values were 3- to 5-fold lower in the CFU-Megs compared with the CFU-GMs). The observation that the Cmax observed in patients treated with the aplidine maximum tolerated dose (MTD) (7.1 nM) was 21-75 fold lower than the IC50(24h) value observed for the different haematopoietic progenitors is highly consistent with the lack of haematotoxicity observed in patients treated with this drug. In the case of ET-743, differences between the Cmax value corresponding to the MTD (2.6 nM) and the in vitro IC50 values corresponding to the different progenitors were much lower (4-19-fold), also consistent with the haematotoxicity that was observed in patients treated at recommended doses (RDs) and MTDs. Although CFU-Megs were more sensitive than CFU-GM progenitors to ET-743 in vitro, clinical data showed that neutropenic events were more frequent than thrombocytopenic episodes. Aiming to further improve the predictive value of in vitro IC values corresponding to the different haematopoietic progenitors, additional refinement parameters derived from pharmacokinetic and animal studies are proposed.
Antineoplastic Agents↗
A comparison of limited sampling strategies for prediction of Ecteinascidin 743 clearance when administered as a 24-h infusion.
PURPOSE: Ecteinascidin 743 (ET-743) is a novel, marine-derived anticancer agent currently under clinical development for the treatment of solid tumors. The aim of this study was to develop and validate limited sampling strategies for the prediction of ET-743 clearance in phase II studies, using two techniques: the stepwise linear regression approach and the Bayesian estimation approach. METHODS: Data from a phase I dose-finding study were used with ET-743 administered as a 24-h infusion. Plasma concentration time data from 34 patients treated with 1200. 1500 or 1800 microg/m2 ET-743 were randomly divided into an index data set, used for the development of the strategies, and a validation data set. With the linear regression approach, clearance (obtained by non-compartmental analysis) was correlated with the ratios of dose to the observed concentrations. For the Bayesian approach a three-compartment population pharmacokinetic model was developed; optimal time-points were selected using the D-optimality algorithm. The strategies were compared by assessment of their predictive performance of CL in the validation data set. RESULTS: The linear regression method yielded a single-point sampling schedule with no significant bias and acceptable precision (-0.03% and 21%, respectively). With the Bayesian approach, a three-sample strategy was selected which resulted in less-accurate, but unbiased, predictions (bias 13%, precision 34%). CONCLUSIONS: Optimal sampling strategies were developed and validated for estimation of ET-743 clearance. Although the linear regression approach showed slightly better predictive performance, the Bayesian approach is preferred for the current phase II studies as it is more robust and flexible and allows the description of the full pharmacokinetic profile.
Adult↗
Chemical and enzymatic stability of a cyclic depsipeptide, the novel, marine-derived, anti-cancer agent kahalalide F.
Kahalalide F is a cyclic depsipeptide isolated from the Hawaiian mollusk Elysia rufescens. This compound is under present phase I clinical investigations as an anti-tumor drug. The role of possible metabolic reactions of this drug in (pre-)clinical investigations has not yet been explored. The first results for kahalalide F in this field of research are given in this paper. The chemical degradation of kahalalide F was investigated under acid, neutral and alkaline conditions using high-performance liquid chromatography with ultraviolet detection. The half-lives at 80 degrees C were 1.1, 20 and 8.6 h at pH 0, 1 and 7, respectively. At 26 degrees C and pH 11, the half-life was 1.65 h. At pH 7 and 11, only one reaction product of kahalalide F was observed, kahalalide G, the hydrolyzed lactone product of kahalalide F. At pH 0 and 1, additional reaction products emerged. Metabolic conversion of kahalalide F was tested in vitro using three different enzyme systems based on pooled human microsomes, pooled human plasma and uridine 5'-diphosphoglucuronyl transferase, respectively. The incubated samples were analyzed using the same chromatographic technique as for the degradation samples. Biotransformations were not observed under these conditions and, therefore, it is concluded that kahalalide F is a metabolically stable drug.
Antineoplastic Agents↗
Search for metabolites of ecteinascidin 743, a novel, marine-derived, anti-cancer agent, in man.
Ecteinascidin 743 (ET-743) is a potent anti-tumoral agent of a marine origin. It is currently being tested in phase II clinical trials using a 3-weekly 24-h i.v. infusion of 1500 microg/m(2) and 3-h infusions of 1650 microg/m(2). Knowledge of the metabolism of ET-743 is, however, still scarce. In the present study, a qualitative chromatographic discovery of metabolites of ET-743 in man is reported. ET-743 and its demethylated analog ET-729 were incubated at 37 degrees C in the presence of enzyme systems, pooled human microsomes, pooled human plasma and uridine 5'-diphosphoglucuronyltransferase, respectively, in appropriate media. Reaction products were investigated chromatographically using photodiode array and ion spray-mass spectrometric detection (LC-MS). The main reaction products in microsomal incubations of ET-743 resulted from a remarkable breakdown of the molecule. In plasma the drugs were deacetylated, and the transferase did actually yield a glucuronide of both ET-743 and ET-729. In contrast, screening of urine, plasma and bile, collected from patients treated with ET-743 at the highest dose levels, using a sensitive LC-MS assay, did not result in detection of ET-729 and metabolites which were generated in vitro. The urinary excretion of ET-743 in man was lower than 0.7% of the administered dose for a 24-h infusion.
Antineoplastic Agents, Alkylating↗
Drug points. Probable interaction between cyclosporin A and low dose ticlopidine.
Explore the source record for details and available documents.
Biological Availability↗
Epidemiologic and clinical aspects of Behçet's disease in a defined area of Northwestern Spain, 1988-1997.
OBJECTIVE: To assess the frequency and clinical manifestations of Behçet's disease (BD) during the past 10 years in a defined area of Northwestern Spain. METHODS: The charts of all the patients diagnosed as having BD at the Hospital Xeral-Calde from 1988 through 1997 were reviewed. All the patients were residents of Lugo. Patients were followed from the time of diagnosis until either the patient's death or July 1, 1998. By that time patients were classified as having complete BD if they fulfilled the International Study Group Criteria (ISG) for BD. Patients with recurrent oral ulcerations plus one of the remaining 4 criteria of the ISG were classified as having an incomplete form of BD. RESULTS: Sixteen patients (9 men/7 women) were diagnosed as having complete BD and 7 (3 men) as having incomplete BD. The average annual incidence rate of complete BD in the Lugo region of Northwestern Spain was 0.66/100,000. Oral ulcerations with or without genital ulcerations were the most common initial manifestations. Neurological involvement was relatively frequent in men with complete BD. In contrast, a positive pathergy test was less common. Two patients with neurological involvement and 3 with uveitis had severe sequelae. However, there was a single death, apparently not related to BD. CONCLUSION: In Northwestern Spain, BD is more common than was expected and is a nonfatal disease. However, central nervous system involvement and severe ocular complications overshadow the good prognosis observed in the majority of patients.
Adolescent↗
Pharmacokinetics and pharmacodynamics of the novel marine-derived anticancer agent ecteinascidin 743 in a phase I dose-finding study.
Ecteinascidin (ET) 743 is an anticancer agent derived from the Caribbean tunicate Ecteinascidia turbinata. Preclinical studies revealed activity of ET-743 against different tumor types. A Phase I clinical trial was designed with ET-743 to identify the maximum tolerated dose and dose-limiting toxicities (DLTs). Furthermore, the pharmacokinetics of ET-743 and relationships with pharmacodynamics were evaluated. Adult patients with solid, resistant tumors received ET-743 as a 24-h i.v. infusion every 21 days. Blood samples were obtained during the first treatment course and in several consecutive courses. Noncompartmental pharmacokinetic analysis was performed. Relationships between pharmacokinetics and hepatic and hematological toxicities were explored. Fifty-two patients were treated at nine dose levels (50-1800 microg/m2). The DLTs, neutropenia and thrombocytopenia, were experienced at 1800 microg/m2. Twenty-five patients were treated at the recommended Phase II dose of 1500 microg/m2. At this dose, the mean value +/- SD for total body clearance was 59 +/- 31 liters/h, and the mean t(1/2) was 89 +/- 41 h. Pharmacokinetics were linear over the dose range tested. Prior exposure to ET-743 did not alter the pharmacokinetics in subsequent courses. The percentage of decrease in WBC count and absolute neutrophil count was correlated to the area under the plasma concentration versus time curve (AUC). Hepatic toxicity, defined as rise in alanine aminotransferase and aspartate aminotransferase, increased with dose and AUC but was reversible and not dose limiting. In conclusion, ET-743 administered as a 24-h i.v. infusion at a dose of 1500 microg/m2 is clinically feasible; severe thrombocytopenia and neutropenia are the DLTs.
Adult↗
[The introduction of generic pharmaceutical products into Galicia].
OBJECTIVE: To know the evolution of the introduction of generic drugs (GDs) in Galicia. Secondarily, to evaluate its potential impact on pharmaceutical expenditure. DESIGN: Descriptive study of GDs utilization. Cost-minimization analysis. SETTING: Galician autonomous region, year 1998. MEASUREMENTS AND RESULTS: Using data from the prescription billing registry of Social Security we have selected the active ingredients corresponding to GDs with prescriptions in Galicia in 1997. We have analyzed the data for their oral single substance preparations by quarters. Consumption in DHDs of allopurinol, atenolol, captopril, naproxen and ranitidine remained stable during 1998. The market share for their GDs in quantitative terms relative to both total consumption of the active ingredients and to their pharmaceutical equivalents, showed an overall growing trend. The maximum observed value was seen for ranitidine at last quarter. Total expenditure (in final customer prices) during 1998 on the selected active substances was higher than 1864 million pesetas. Potential savings afforded by substitution for the lowest price GD prescribed in Galicia would reach 427 million pesetas. CONCLUSIONS: GDs market penetration in Galicia during 1998 was limited but increasing. Its utilization may afford estimated savings of 21-28% of the cost for the selected drugs. However, the expenditure on the above drugs was just 2.7% of total pharmaceutical expenditure.
Cost Savings↗
Drug associated cutaneous vasculitis in adults in northwestern Spain.
OBJECTIVE: To examine the incidence and clinical features of adults with biopsy proven cutaneous vasculitis (CV) associated with drugs. METHODS: Retrospective study of an unselected population of adults (age >20 years) with biopsy proven leukocytoclastic CV from 1988 through 1997. Drug associated CV was considered if CV was confirmed by a skin biopsy and there was a history of drug use within one week before the development of CV. Drug associated CV was classified by American College of Rheumatology (ACR) criteria. To differentiate Henoch-Schonlein purpura (HSP) from hypersensitivity vasculitis (HV), the traditional criteria proposed by Michel, et al were used (J. Rheumatol. 1992;19:721-8). RESULTS: Thirty-three of 138 patients (23.9%) presenting with biopsy proven CV were diagnosed with drug associated CV. The annual incidence rate of biopsy proven drug associated CV in adults was 17.49 cases/million (95% CI 11.53-23.46): men 25.10/million (95% CI 14.85-35.36), women 10.31/million (95% CI 3.92-16.70). Antibiotics (n = 13), especially amoxicillin, and analgesics or nonsteroidal anti-inflammatory drugs (n = 11) were the drugs more commonly associated with CV. All adults with drug associated CV met the ACR classification criteria for HV or HSP. Based on Michel's criteria 26 patients (78.8%) were classified as having HV and 7 HSP. No patient met ACR criteria for other systemic vasculitides. Complete recovery with no sequelae was observed in most cases. CONCLUSION: Among patients with CV, drug associated disease is common and usually has a good clinical outcome.
Adult↗
Acute myocardial infarction associated with sildenafil.
Explore the source record for details and available documents.
3',5'-Cyclic-GMP Phosphodiesterases↗
In vitro hematotoxicity of Aplidine on human bone marrow and cord blood progenitor cells.
Aplidine is a cyclic depsipeptide that was isolated from a Mediterranean marine tunicate, Aplidium albicans. In experimental animals, Aplidine mediated an in vivo inhibitory effect in a number of tumor cell types. In humans, Aplidine is currently used in phase I clinical trials. Aiming to predict the hematotoxicity of Aplidine in humans, samples from human bone marrow (BM) and cord blood (CB) were exposed in vitro to increasing concentrations of the drug and then assayed for the clonogenic ability of myeloid (CFU-GM), erythroid (BFU-E), megakaryocitic (CFU-Meg) and pluripotent (CFU-Mix) hematopoietic progenitors. We investigated whether predictions of the hematotoxicity of Aplidine based on bone marrow (BM) cultures were reproduced when a more readily available source of human hematopoietic cells, cord blood cells, was used in experiments involving 24-h exposures. Although hematopoietic progenitors derived from bone marrow were generally more sensitive than those derived from cord blood, differences on the IC50, IC70 and IC90 varied within a relatively small range of 1.6-6.2-fold. Moreover, data obtained from cord blood cultures confirmed the observation made in bone marrow assays indicating that the myeloid (CFU-GM) and the erythroid (BFU-E) progenitors were the least sensitive to Aplidine. Regardless of the origin of the hematopoietic progenitors (bone marrow or cord blood) the toxicity of Aplidine in human hematopoietic progenitors (IC50: 150-2250 nM) was lower than that observed in previous studies with tumoral cell lines.
Antineoplastic Agents↗
Evaluation of the use of in vitro methodologies as tools for screening new compounds for potential in vivo toxicity.
Explore the source record for details and available documents.
Animal Testing Alternatives↗