Paschoalina Romano

The need of mycophenolic acid monitoring in long-term renal transplants.

Abstract:  Background:  There is little information regarding the 12‐h mycophenolic acid (MPA) pharmacokinetics (PK), a way to monitor the drug and the need of frequent monitoring, in stable patients.

Bioequivalence of a new cyclosporine a formulation to Neoral.

New cyclosporine A (CsA) formulations must prove their bioequivalence to Neoral®, the reference CsA formulation, to allow free prescription for the patients. The aim of this study was to compare the pharmacokinetics (PK) of a new CsA formulation (Zinograf-ME), produced by Strides-Arcolab, to Neoral and to demonstrate their interchangeability in stable renal transplant recipients. Twelve-hour PK studies were obtained from 18 (13 M/5 F) adult patients (mean age 44.7 ± 12 years). They received their renal allografts from 13 cadaver and 5 living donors. Before enrollment, all patients were receiving a third generic CsA for a mean of 48 months. Nine patients were also under azathioprine and 9 under mycophenolate mofetil; 17 received prednisone. A single oral dose of either Zinograf or Neoral was administered. The first PK study was performed with one formulation, and 1 week later, a second PK was done with the other formulation. During the washout period, patients continued taking the third CsA formulation. The drug substitution was done milligram-for-milligram. The CsA whole-blood level was measured by TDx immunoassay. Mean ± SD of area under the curve (AUC), maximum concentration (C max), and concentration at the second hour (C2) of Zinograf were not statistically different from those with Neoral (4019 ± 1466 vs 3971 ± 1325 ng·h/mL, 998 ± 376 vs 1021 ± 356 ng/mL, and 707 ± 254 vs 734 ± 229 ng/mL, respectively). In the same way, the Zinograf 90% confidence interval for either C max (−123, +77 ng/mL) or AUC (−214, +311 ng·mL/h) were within the Neoral bioequivalence interval for the same parameters (±204 ng/mL and ±794 ng·mL/h, respectively). These data demonstrate that the ZinografME CsA formulation is bioequivalent to Neoral.

Diminished mycophenolic acid exposure caused by omeprazole may be clinically relevant in the first week posttransplantation.

Background: Some studies have reported a decreased absorption of mycophenolic acid (MPA) from mycophenolate mofetil (MMF) in renal transplanted (RTx) patients under proton-pump inhibitors (PPIs). There is still a lack of information regarding (1) whether this effect occurs when MMF is administered with either tacrolimus or cyclosporine A [calcineurin inhibitors (CNIs)], (2) whether the effect has the same amplitude during the first year after RTx, and finally (3) whether this decrease in exposure is clinically relevant. Methods: We retrospectively analyzed the omeprazole effect in 348 12-hour pharmacokinetic samplings [area under the curve (AUC)0–12h] performed on days 7, 14, 30, 60, 180, and 360 after RTx in 77 patients who participated in previous trials. Results: For all periods, the groups with and without PPI did not differ in all variables. By mixed-model analysis of variance, PPI reduced the MPA AUC0–12h (P < 0.0008) in the patients under both CNIs mainly due to decreased absorption (P = 0.049). In the tacrolimus group, a lower exposure seemed also due to a decreased MPA reabsorption at 10–12 hours. The PPI effect remains throughout the first year but was clinically more important on day 7. By Cox analysis, the use of PPI was associated with a 25% less chance of being adequately exposed to MPA (95% confidence interval 0.58–0.99, P = 0.04). Similarly, the number of patients underexposed to MPA (AUC < 30 ng·h/mL) was higher at most periods in the PPI group but again not statistically significant. Conclusions: These data indicate that PPI decreases the MPA exposure when associated with both CNIs but particularly in the first week after RTx. In this period, the MMF dose should be increased. This effect lasts throughout the first year but does not seem to be clinically relevant after the first week.

Practical aspects of the use of FMEA tool in clinical laboratory risk management

INTRODUCAO: O artigo apresenta a ferramenta de analise do modo e do efeito de falhas (FMEA) dentro de um laboratorio clinico por meio da introducao de nova tecnologia para gasometria e calcio ionico serico em analisadores multiparâmetros do tipo testes laboratoriais remotos (TLR) ou point of care testing (POCT). OBJETIVO: Apresentar a FMEA como ferramenta de gestao de riscos e de melhoria em um laboratorio publico ao introduzir novas tecnologias. METODOS: A mudanca de analisadores de gases multiparâmetros do tipo POCT foi definida e descrita como um processo. A seguir, foram apresentados os criterios para a avaliacao dos riscos e a sua quantificacao. Foram estudados os modos de falha pelos quais algo poderia falhar nos componentes desse processo. Estabeleceram-se tres planos de acoes que envolviam melhorias a serem introduzidas na mudanca de tecnologia. A FMEA foi aplicada em dois momentos: no inicio do projeto e apos a implantacao das medidas propostas. RESULTADOS: O primeiro plano envolveu medidas administrativas vinculadas ao processo licitatorio; a segunda acao preventiva envolveu a possibilidade de qual fornecedor venceria a licitacao, estudando-se a eficiencia do analisador e seu impacto na produtividade; o terceiro conjunto de acoes foi dirigido as melhorias no relacionamento com o corpo clinico para minimizar as eventuais reclamacoes. As ultimas acoes referiram-se a contratacao de novos funcionarios para atender a demanda crescente. CONCLUSAO: A FMEA revelou-se um instrumento de melhoria de desempenho para o laboratorio, que de maneira proativa identifica, prioriza e mitiga os riscos do paciente.

Longitudinal Pharmacokinetics of Tacrolimus in Elderly Compared With Younger Recipients in the First 6 Months After Renal Transplantation

Background Elderly (Eld) (≥60 years) recipients are receiving renal transplants more frequently. The pharmacokinetics (PK) studies of immunosuppressive drugs in healthy volunteers, rarely, include old patients. Methods We studied 208 12-hour tacrolimus (TAC) PK (0, 20, 40, 60, 90, 120, 180, 240, 360, 480, 600, 720 min) in 44 Eld (65 ± 3 years) and compared the results with 31 younger controls (Ctrl) (35 ± 6 years) recipients, taking oral TAC/mycophenolate sodium (MPS)/prednisone, at 4 different timepoints: PK1 (8 ± 2 days; n = 72), PK2 (31 ± 4 days; n = 61), PK3 (63 ± 6 days; n = 44), and PK4 (185 ± 10 days; n = 31). Tacrolimus PK was measured by ultraperformance liquid chromatography coupled to a mass spectrometer repetition and noncompartmental PKs were analyzed using Phoenix WinNonlin. Results Mean TAC dose was lower in the Eld group than in Ctrl ones throughout timepoints either by total daily dose or adjusted (Adj) per body weight. Mean TAC trough level (Cmin), used to adjust daily dose, was not different between the 2 groups in all timepoints. AdjCmax and AdjTAC-area under the curve at dosing interval were both higher in the Eld compared to the Ctrl group in PKs1, 3, and 4. Estimated total body clearance normalized by dose and weight was lower in the Eld group compared with the Ctrl in all PKs and statistically lower at PKs 1 and 3. Similar to younger recipients TAC trough level has also a high correlation (R2 = 0.76) with area under the curve at dosing interval. Conclusions These data indicate that Eld recipients have a lower TAC clearance and therefore need a lower TAC dose than younger recipients.

Longitudinal Pharmacokinetics of Everolimus when Combined with Low-level of Tacrolimus in Elderly Renal Transplant Recipients.

Background Although the proportion of elderly patients among renal transplant recipients has increased, pharmacokinetic (PK) studies of immunosuppressants rarely include older patients. Methods We studied 12-hour everolimus (EVL) PK in 16 elderly renal transplant recipients (all whites; 10 men; mean age, 64 ± 2 years (61-71 years), in 4 separate timepoints (at 7, 30, 60, and 150 days) after EVL introduction, corresponding to a mean postrenal transplantation day: PK1 (43 ± 4 days), PK2 (65 ± 7 days), PK3 (106 ± 17 days), and PK4 (206 ± 40 days). Patients received EVL (target trough level (Ctrough, 3-8 ng/mL), prednisone, and tacrolimus (TCL) (target Ctrough, 2-5 ng/mL). Results Mean TCL-Ctrough was 7.2 ± 3.8, 4.9 ± 2.2, 4.9 ± 2.2, and 4.5 ± 1.2 ng/mL at PK1, PK2, PK3, and PK4, respectively. There were no differences among timepoints for mean EVL daily dose (data shown as PK3) (3.5 ± 1.3 mg/d), Ctrough (4.7 ± 2.5 ng/mL), AUC0-12h (106 ± 51 ng/h per mL), Caverage (8.8 ± 4.2 ng/mL), Cmax (19.2 ± 9.7 ng/mL), apparent Half-life (11.7 ± 4.2 hours), estimated total body clearance (0.39 ± 0.27 L/h), or fluctuation (166 ± 65%). Also, none of those PK parameters differed statistically when adjusted for body weight. EVL-Ctrough showed a very high correlation (r2 = 0.849) with AUC0-12h. Conclusions Our data indicate that elderly renal transplant recipients starting EVL 1 month after transplantation along with a steady-state TCL level, present stable EVL-PK parameters without significant changes in dose or exposure during the first 6 months after renal transplantation.

Indicadores de sustentabilidade em medicina laboratorial

The article presents the conceptual principles on sustainable development and sustainability. Furthermore, it evaluates the progress and impacts on the economy, environment and society. It discusses the applicability of the concepts of corporate sustainability in laboratory medicine and the challenges of deployment in the clinical laboratory. The impact of sustainability indicators and their role in management are also critically reviewed from the perspective of social and environmental balance. Additionally, the text provides some tools for evaluation and interpretation of indicators and their corresponding application in the critical analysis process. Lastly, the article describes the importance of sustainability indicators in the practice of benchmarking and its applicability in the clinical laboratory

UPLC-MS/MS assay validation for tacrolimus quantitative determination in peripheral blood T CD4+and B CD19+lymphocytes

&NA; Monitoring tacrolimus (Tac) exposure in cell matrices enriched with lymphocytes can improve Tac therapeutic drug monitoring (TDM) in solid organ transplant recipients. An UPLC–MS/MS based assay for Tac quantification in peripheral blood T CD4+ and B CD19+ lymphocytes was developed. Peripheral blood mononuclear cells (PBMC) were obtained by density gradient centrifugation and highly purified (purity >90%) T CD4+ and B CD19+ cell suspensions were acquired by magnetic negative selection from whole blood of 6 healthy volunteers. The purity of lymphocyte suspensions was checked by flow cytometry. Tac extraction was performed in a liquid–liquid zinc sulfate, methanol and acetonitrile based medium. Ascomycin was used as internal standard. The equipment used was a Waters® Acquity™ UPLC system (Waters Corporation, Milford, MA, USA). The chromatographic run was performed on a Waters® MassTrak TDM C18 (2.1 × 10 mm) column (Waters Corporation, Milford, MA, USA). at a flow rate of 0.4 mL/min. The instrument was set in electrospray positive ionization mode. The method was validated according to Clinical Laboratory Standard Institute (CLSI) guidelines and showed a high sensitivity and specificity over a range of 0–5.2 ng/mL in PBMC, 0–5.0 ng/mL in T CD4+ Lymphocytes and 0–5.3 ng/mL in B CD19+ lymphocytes. Precision was appropriate with CV of intra‐assay quantifications ranging from 4.9 to 7.4%, and of inter‐assay quantifications from 7.2 to 13.9%. Limit of detection and quantification were 0.100 and 0.115 ng/mL in PBMC, 0.058 and 0.109 ng/mL in T CD4+ and 0.017 and 0.150 ng/mL in B CD19+ cells. Matrix effect was not significant among all the studied matrices. Samples showed stability for Tac quantification over a period of 90 days either at room temperature or at −30 °C storage conditions. The method was applied to clinical samples of 20 kidney transplant recipients. Concentrations ranged from 2.200 to 11.900 ng/mL in whole blood, from 0.005 to 0.570 ng/106 cells in PBMC, from 0.081 to 1.432 ng/106 cells in T CD4+, and from 0.197 to 1.564 ng/106 cells in B CD19+ cell matrices. The method has potential applicability for Tac TDM in solid organ transplant recipients.

Validation protocol for multiple blood gas analyzers in accordance with laboratory accreditation programs

Introduction:The results of blood gas analysis using different instrumentation can vary widely due to the methodological differences, the calibration procedures and the use of different configurations for each type of instrument.Objective:The objective of this study was to evaluate multiple analytical systems for measurement of blood gases, electrolytes and metabolites in accordance with the accreditation program (PALC) of Sociedade Brasileira de Patologia Clinica/Medicina Laboratorial (SBPC/ML).Materials and methods:20 samples were evaluated in three ABL800 Flex (Radiometer Medical ApS, Denmark) blood gas analyzers, and the results were compared with those of the device in use, which was considered the reference. The analysis of variance (Anova) was applied for statistical purposes, as well as the calculation of mean, standard deviation and coefficient of variation.Results:The p values obtained in the statistical analysis were: pH = 0.983, pO2 = 0.991, pCO2 = 0.353, lactate = 0.584, glucose = 0.995, ionized calcium = 0.983, sodium = 0.991, potassium = 0.926, chlorine = 0.029.Conclusion:The evaluation of multiple analytical systems is an essential procedure in the clinical laboratory for quality assurance and accuracy of the results.