A Joint Pharmacokinetic Model for the Simultaneous Description of Plasma and Whole Blood Tacrolimus Concentrations in Kidney and Lung Transplant Recipients.

BACKGROUND AND OBJECTIVE: Historically, dosing of tacrolimus is guided by therapeutic drug monitoring (TDM) of the whole blood concentration, which is strongly influenced by haematocrit. The therapeutic and adverse effects are however expected to be driven by the unbound exposure, which could be better represented by measuring plasma concentrations. OBJECTIVE: We aimed to establish plasma concentration ranges reflecting whole blood concentrations within currently used target ranges. METHODS: Plasma and whole blood tacrolimus concentrations were determined in samples of transplant recipients included in the TransplantLines Biobank and Cohort Study. Targeted whole blood trough concentrations are 4-6 ng/mL and 7-10 ng/mL for kidney and lung transplant recipients, respectively. A population pharmacokinetic model was developed using non-linear mixed-effects modelling. Simulations were performed to infer plasma concentration ranges corresponding to whole blood target ranges. RESULTS: Plasma (n = 1973) and whole blood (n = 1961) tacrolimus concentrations were determined in 1060 transplant recipients. A one-compartment model with fixed first-order absorption and estimated first-order elimination characterised observed plasma concentrations. Plasma was linked to whole blood using a saturable binding equation (maximum binding 35.7 ng/mL, 95% confidence interval (CI) 31.0-40.4 ng/mL; dissociation constant 0.24 ng/mL, 95% CI 0.19-0.29 ng/mL). Model simulations indicate that patients within the whole blood target range are expected to have plasma concentrations (95% prediction interval) of 0.06-0.26 ng/mL and 0.10-0.93 ng/mL for kidney and lung transplant recipients, respectively. CONCLUSION: Whole blood tacrolimus target ranges, currently used to guide TDM, were translated to plasma concentration ranges of 0.06-0.26 ng/mL and 0.10-0.93 ng/mL for kidney and lung transplant recipients, respectively.

Ultra-high throughput dual channel liquid chromatography with tandem mass spectrometry for quantification of four immunosuppressants in whole blood for therapeutic drug monitoring.

Liquid chromatography with tandem mass spectrometry (LC-MS/MS) is the golden standard for immunosuppressants analyses, where optimising throughput by parallel chromatography can reduce costs and turnaround time. We aimed to double our system throughput using a dual LC-MS/MS setup. Therefore, two independent UPLC systems were hyphenated to one triple quadrupole MS, with staggered injections from one autosampler on alternating columns. The method simultaneously measured the analytes tacrolimus, sirolimus, everolimus, and cyclosporin A in whole blood using isotope dilution, with a run time of 1.5 min. Using the dual LC-MS/MS system, net run-to-run time improved from 2.3 to 0.98 min per injection, where throughput increased from 26 to 61 injections per hour. For Performance Qualification, 1101 clinical samples were measured on the dual LC-MS/MS system in addition to the standard system, during a period of one month, and the results were compared using Passing Bablok regression and Bland Altman analysis. There was excellent agreement for all four analytes, with regression slopes of 0.98-1.02x and intercepts of -0.11-0.88 µg/L. Minor bias was demonstrated between the systems with mean differences from -0.93 to 1.43%. In conclusion, the throughput was doubled and idle MS time was reduced with good agreement to the standard system. Currently, the method is applied for clinical routine with frequent peak intensities of >180 injections per day.

Expeditious quantification of plasma tacrolimus with liquid chromatography tandem mass spectrometry in solid organ transplantation.

Traditionally, tacrolimus is assessed in whole blood samples, but this is suboptimal from the perspective that erythrocyte-bound tacrolimus is not a good representative of the active fraction. In this work, a straightforward and rapid method was developed for determination of plasma tacrolimus in solid organ transplant recipients, using liquid chromatography tandem mass spectrometry (LC-MS/MS) with heated electrospray ionisation. Sample preparation was performed through protein precipitation of 200 µl plasma with 500 µl stable isotopically labelled tacrolimus I.S. in methanol, where 20 µl was injected on the LC-MS/MS system. Separation was done using a chromatographic gradient on a C18 column (50 × 2.1 mm, 2.6 µm). The method was linear in the concentration range 0.05-5.00 µg/L, with within-run and between-run precision in the range 2-6 % and a run time of 1.5 min. Furthermore, the method was validated for selectivity, sensitivity, carry-over, accuracy and precision, process efficiency, recovery, matrix effect, and stability following EMA and FDA guidelines. Clinical validation was performed in 2333 samples from 1325 solid organ transplant recipients using tacrolimus (liver n = 312, kidney n = 1714, and lung n = 307), which had median plasma tacrolimus trough concentrations of 0.10 µg/L, 0.15 µg/L and 0.23 µg/L, respectively. This method is suitable for measurement of tacrolimus in plasma and will facilitate ongoing observational and prospective studies on the relationship of plasma tacrolimus concentrations with clinical outcomes.

Electronic Smart Blister Packages to Monitor and Support Medication Adherence: A Usability Study.

Purpose: An electronic version of the Dosepak® (EDP) which records date and time of dosing events has been developed to monitor adherence to medication packaged in blisters. This study aimed to evaluate its usability and acceptance and to monitor dose-taking adherence for optimal implementation in future clinical trials and practice. Methods: Healthy volunteers aged over 18 years were asked to dispense placebo tablets twice daily from EDPs equipped with a re-usable electronic module for a total duration of four weeks. Afterwards, subjects were asked to complete an online questionnaire and partake in a short one-on-one interview. The usability of the EDP was assessed using the System Usability Scale (SUS), while dose-taking adherence was monitored by EDP records, pill counting, and self-report. The short interview explored user experiences in more detail. Results: Twenty subjects with median [IQR] age 41.5 [32-49.8] years, 55% female, 45% healthcare professionals, and 20% chronic medication users completed the study and found the EDP easy to use, with a mean [SD] SUS score of 78.0 [11.2]. Median [IQR] dose-taking adherence was 89% [82-95%] based on EDP records, 96.5% [89-100%] based on pill counting, 92% [91-96%] based on self-report, and the levels differed significantly (p < 0.05). Four themes emerged from the interviews: user preference, experience, patient burden, and ideas for improvement. Most participants preferred smaller sized blisters. They found the EDP simple to use and did not see any patient burden for its use in trials or clinical practice. Some reported forgetfulness and suggested reminders built into the blister or sent to their mobile phones. Adequate information or instruction should also be provided for older people and polypharmacy patients. Conclusion: EDP had good perceived usability, was well accepted, and differed significantly from other adherence measurement methods. This study provides input to further guide scale-up of the blister packages.

Digital spacer data driven COPD inhaler adherence education: The OUTERSPACE proof-of-concept study.

Pressurized metered dose inhalers are recommended to be used in combination with spacers, yet inhaler technique and adherence are poor. A novel digital "smart" spacer can record spacer use and technique errors and could facilitate personalized education. In this proof-of-concept study, we assessed the usability of the digital spacer and explored its effects on inhaler technique, adherence, long-term systemic drug exposure and clinical outcomes in COPD. Usability was deemed high. One month after personalized digital spacer inhaler education, the mean number of errors per patient per day decreased with 36%, from 6.40 errors/day to 4.07 errors/day (p = 0.038). Drug exposure was confirmed by bioanalytical scalp hair analysis of formoterol. No significant change in clinical outcomes was observed. This study demonstrates the digital spacer's potential value in inhaler education, but larger, longer-term studies are required.

Clinical Value of Emerging Bioanalytical Methods for Drug Measurements: A Scoping Review of Their Applicability for Medication Adherence and Therapeutic Drug Monitoring.

INTRODUCTION: Direct quantification of drug concentrations allows for medication adherence monitoring (MAM) and therapeutic drug monitoring (TDM). Multiple less invasive methods have been developed in recent years: dried blood spots (DBS), saliva, and hair analyses. AIM: To provide an overview of emerging drug quantification methods for MAM and TDM, focusing on the clinical validation of methods in patients prescribed chronic drug therapies. METHODS: A scoping review was performed using a systematic search in three electronic databases covering the period 2000-2020. Screening and inclusion were performed by two independent reviewers in Rayyan. Data from the articles were aggregated in a REDCap database. The main outcome was clinical validity of methods based on study sample size, means of cross-validation, and method description. Outcomes were reported by matrix, therapeutic area and application (MAM and/or TDM). RESULTS: A total of 4590 studies were identified and 175 articles were finally included; 57 on DBS, 66 on saliva and 55 on hair analyses. Most reports were in the fields of neurological diseases (37%), infectious diseases (31%), and transplantation (14%). An overview of clinical validation was generated of all measured drugs. A total of 62 drugs assays were applied for MAM and 131 for TDM. CONCLUSION: MAM and TDM are increasingly possible without traditional invasive blood sampling: the strengths and limitations of DBS, saliva, and hair differ, but all have potential for valid and more convenient drug monitoring. To strengthen the quality and comparability of future evidence, standardisation of the clinical validation of the methods is recommended.

Enantiomer-specific pharmacokinetics of D,L-3-hydroxybutyrate: Implications for the treatment of multiple acyl-CoA dehydrogenase deficiency.

D,L-3-hydroxybutyrate (D,L-3-HB, a ketone body) treatment has been described in several inborn errors of metabolism, including multiple acyl-CoA dehydrogenase deficiency (MADD; glutaric aciduria type II). We aimed to improve the understanding of enantiomer-specific pharmacokinetics of D,L-3-HB. Using UPLC-MS/MS, we analyzed D-3-HB and L-3-HB concentrations in blood samples from three MADD patients, and blood and tissue samples from healthy rats, upon D,L-3-HB salt administration (patients: 736-1123 mg/kg/day; rats: 1579-6317 mg/kg/day of salt-free D,L-3-HB). D,L-3-HB administration caused substantially higher L-3-HB concentrations than D-3-HB. In MADD patients, both enantiomers peaked at 30 to 60 minutes, and approached baseline after 3 hours. In rats, D,L-3-HB administration significantly increased Cmax and AUC of D-3-HB in a dose-dependent manner (controls vs ascending dose groups for Cmax : 0.10 vs 0.30-0.35-0.50 mmol/L, and AUC: 14 vs 58-71-106 minutes*mmol/L), whereas for L-3-HB the increases were significant compared to controls, but not dose proportional (Cmax : 0.01 vs 1.88-1.92-1.98 mmol/L, and AUC: 1 vs 380-454-479 minutes*mmol/L). L-3-HB concentrations increased extensively in brain, heart, liver, and muscle, whereas the most profound rise in D-3-HB was observed in heart and liver. Our study provides important knowledge on the absorption and distribution upon oral D,L-3-HB. The enantiomer-specific pharmacokinetics implies differential metabolic fates of D-3-HB and L-3-HB.

User Acceptability and Technical Robustness Evaluation of a Novel Smart Pill Bottle Prototype Designed to Support Medication Adherence.

PURPOSE: Smart medication adherence monitoring devices can provide objective and granular drug utilization data and help patients engaging with their treatment. In this proof-of-concept study, the acceptability and technical robustness of a novel smart pill bottle prototype (SPBP) were assessed in order to allow further optimization. METHODS: The SPBP is an app-controlled automatic dispense system, capturing real-time data on a web-based platform, which sends text reminders and measures storage conditions. A heterogeneous group of ten volunteers was asked to dispense placebo capsules with the SPBP and to follow a predefined dosing schedule for a trial period of 2 weeks. Afterwards, a questionnaire was filled out during a short interview. Primary outcome was dispense adherence as measured by the bottle. Other study outcomes included system acceptability (System Usability Scale [SUS]), self-reported adherence (MARS) and technical robustness of the bottle's mechanics (electronic pill dispenser) and sensors (bottle temperature). RESULTS: The overall dispense adherence rate as measured by the SPBP was 88%. All participants completed the study and four participants had an adherence rate of 100% during the study. The dispense adherence rates corresponded well with participants' self-reported adherence with an average MARS total score of 23.6 (out of 25). Participants judged the system easy to use, with a mean SUS score of 79.3 (range: 57.5-97.5). The overall mean temperature difference between the bottle sensor and calibrated external sensor was -0.82°C (range: -1.37°C to -0.21°C). CONCLUSION: The SPBP was well accepted and this study provides data for further optimization and follow-up studies. Smart adherence technologies such as these may change the way healthcare professionals, trialists and patients manage medication adherence.

Effects of prophylactic antibiotics on patients with stable COPD: a systematic review and meta-analysis of randomized controlled trials.

Background: As bacterial infections provoke exacerbations, COPD patients may benefit from prophylactic antibiotics. However, evidence regarding their overall benefit-risk profile is conflicting. Objectives: To update previous evidence and systematically evaluate the beneficial effects and side effects of prophylactic antibiotics in stable COPD patients. Methods: Several databases were searched up to 26 April 2017 for randomized controlled trials (RCTs) on prophylactic antibiotics in stable COPD patients. The primary outcomes were exacerbations and quality of life. Duration and schedule of antibiotics were considered in subgroup analyses. Results: Twelve RCTs involving 3683 patients were included. Prophylactic antibiotics significantly reduced the frequency of exacerbations [risk ratio (RR) 0.74, 95% CI 0.60-0.92] and the number of patients with one or more exacerbations (RR 0.82, 95% CI 0.74-0.90). Erythromycin and azithromycin appeared the most effective, with the number needed to treat ranging from four to seven. Quality of life was also significantly improved by prophylactic antibiotics (mean difference -1.55, 95% CI -2.59 to -0.51). Time to first exacerbation was prolonged in six studies, with one conflicting result. Neither the rate of hospitalization nor the rate of adverse events was significantly changed. Furthermore, no significant changes were observed in lung function, bacterial load and airway inflammation. However, antibiotic-resistant isolates were significantly increased (OR 4.49, 95% CI 2.48-8.12). Conclusions: Prophylactic antibiotics were effective in preventing COPD exacerbations and improving quality of life among stable patients with moderate to severe COPD. The choice of prophylactic antibiotics should be analysed and considered case by case, especially for long and continuous use.