Two decades (1998 to 2018) of collaborative human immunodeficiency virus clinical pharmacology capacity building in a resource constrained setting.

While important advances have been made in the prevention and treatment of Human Immunodeficiency Virus (HIV) infection, limited expertise and resource constraints to effectively manage rollout of HIV programs often contribute to poor treatment outcomes in Sub-Saharan Africa. In 1998, the University of Zimbabwe (UZ) and the University at Buffalo, State University of New York (UB), developed a collaborative clinical pharmacology capacity building program in Zimbabwe to train the next generation of HIV researchers and support rollout of the national HIV program. The collaboration was funded by research and training grants that were competitively acquired through United States of America government funding mechanisms, between 1998 and 2016. Thirty-eight research fellows were trained and a specialty clinical pharmacology laboratory was established during this period. Knowledge and skills transfer were achieved through faculty and student exchange visits. Scientific dissemination output included sixty-two scholarly publications that influenced three national policies and provided development of guidelines for strategic leadership for an HIV infection-patient adherence support group. The clinical pharmacology capacity building program trained fellows that were subsequently incorporated into the national technical working group at the Ministry of Health and Child Care, who are responsible for optimizing HIV treatment guidelines in Zimbabwe. Despite serious economic challenges, consistent collaboration between UZ and UB strengthened UZ faculty scholarly capacity, retention of HIV clinical research workforce was achieved, and the program made additional contributions toward optimization of antiretroviral therapy in Zimbabwe.

Cross-validation of a high-performance liquid chromatography nevirapine plasma assay in a resource-limited setting in Zimbabwe.

An international HIV pharmacology specialty laboratory (PSL) was established at the University of Zimbabwe to increase bioanalytical and investigator capacities. Quantitation of plasma nevirapine in samples from the AIDS Clinical Trials Group protocol 5279 was compared between the University of Nebraska Medical Center PSL and the University of Zimbabwe PSL. Both PSLs employed internally developed methods utilising reverse-phase high-performance liquid chromatography with ultraviolet detection. Eighty-seven percent of the cross-validation results exhibited ± 20% difference.

Development and validation of a high performance liquid chromatography method to determine nevirapine in plasma in a resource-limited setting.

BACKGROUND: There are several instances where nevirapine pharmacokinetic monitoring may be useful, such as in special populations or pharmacokinetic drug interaction studies that require the ascertainment of nevirapine pharmacokinetics in the sub-Saharan region. OBJECTIVES: The main aim of this study was to produce a validated, sustainable and relevant nevirapine assay method that meets bio-analytical regulatory requirements. METHODS: The developed method utilised a Waters 2795 Alliance high performance liquid chromatography system with a 2996 photo diode array detector, an Atlantis dC18 5 micron, 3.9 mm × 150 mm analytical column and a gradient flow rate of 1 mL/min. Ultraviolet detection data were collected from 210 nm to 400 nm, extracted at 260 nm, and processed for nevirapine and internal standard peak height responses. RESULTS: The method proved to be linear (R2 0.995), precise (+1.92% - +9.69%) and accurate (-9.70% - 12.0%). Recovery for the analyte and internal standard was between 98.8% and 114%. The method showed good specificity as no interferences were caused by common African traditional medicines, anti-tuberculosis medications or other concomitant antiretrovirals nor endogenous components. CONCLUSION: The method is reproducible, relevant to our setting and uses considerably low plasma volumes with preservation of some consumables, a desirable key factor in a resource-limited setting.

Sources of Variability and Accuracy of Performance Assessment in the Clinical Pharmacology Quality Assurance Proficiency Testing Program for Antiretrovirals.

BACKGROUND: The Clinical Pharmacology Quality Assurance (CPQA) program provides semiannual proficiency testing (PT) of antiretroviral analytes for 11 US and international clinical pharmacology laboratories (CPLs) to ensure interlaboratory comparability. In this article, we provide estimates of the main sources of variability and assess the accuracy of the algorithm for the assessment of performance. METHODS: Descriptive statistics are reported from 13 PT rounds from 2010 to 2016. Eight of the most common antiretroviral analytes were examined. Variance components analysis was used to rank the relative contributions of CPLs, antiretroviral analyte, and concentration category (low, medium, and high) to bias and variability using mixed models. Binary classification metrics of the PT assessment algorithm are calculated in comparison with a model using 95% prediction limits around estimated regression equations. RESULTS: CPLs provided 4109 reported concentrations of 65 unique samples for each of the 8 antiretroviral analytes across 13 PT rounds. Individual CPL accounted for the greatest amount of total variability (4.4%). Individual CPL and analyte combination (interaction) accounted for the greatest amount of bias (8.1%). Analyte alone accounted for 0.5% or less for total variability and bias. Overall, using a ±20% acceptance window around the final target, 97% of individual reported concentrations were scored acceptable, and 96% of antiretroviral/round scores were deemed satisfactory. Comparison with the regression model gave 100% sensitivity but only 34.47% specificity. Narrowing the acceptance window to ±15% improved specificity to 84.47% while maintaining a 99.17% sensitivity. CONCLUSIONS: The current CPQA PT scoring algorithm that use a ±20% acceptance window seems to suffer from a low specificity and may be too lenient. A stricter ±15% acceptance window would increase specificity and overall accuracy while lowering the overall pass rate by only 3%.

Development and validation of an assay to measure cannabidiol and Δ9-tetrahydrocannabinol in human EDTA plasma by UHPLC-MS/MS.

The therapeutic use of cannabinoids has increased with providers often recommending cannabinoid-containing products with limited pre-clinical and clinical pharmacokinetic studies. An ultra-performance liquid chromatography with triple quadrupole mass spectrometry method was developed and validated for the determination of cannabidiol and Δ9-tetrahydrocannabinol in human ethylenediaminetetraacetic acid (EDTA) plasma. The cannabinoids are extracted from plasma with a liquid-liquid procedure utilizing methyl tert-butyl ether. UHPLC Separation was achieved with a Waters Acquity HSS T3 column (100 × 2.1 mm, 1.8 µm) under isocratic conditions (18:82:0.02 water:methanol:formic acid v/v/v). The run time was 8.5 min. Detection of analytes was achieved using electrospray ionization and triple quadrupole selected reaction monitoring. Standard curve concentrations ranged from 0.5 to 250 ng/mL for cannabidiol and Δ9-tetrahydrocannabinol. The intra- and inter-day accuracy (% bias) and precision (relative standard deviation) were <9.20% in low, medium, and high quality control samples. The validated method was applied to the analysis of donated human EDTA plasma. The assay provides an important patient monitoring capability to determine variability in clinical pharmacokinetics during use of cannabinoid-containing products.

Mentored postdoctoral training in Zimbabwe: A report on a successful collaborative effort.

Low-and-middle-income countries (LMICs) have high disease burdens, necessitating increased research. However, LMIC research output constitutes only 2% of global total. To increase output, researchers must be capacitated. The University of Zimbabwe (UZ) and the University at Buffalo (UB), developed and implemented the AIDS International Research Training Program (AITRP), in 2008, that focused on graduate scholars. The subsequent HIV Research Training Program (HRTP), begun in 2016, and piloted post-doctoral training to enhance research productivity at UZ. This report discusses the collaboration. As of 2016, prospective candidates applied by submitting letters of intent, research proposals, curriculum vitae and biographical sketches. The scholars research training included hypothesis and project development, completion of grant applications, research project budgets, research presentations to diverse audiences and the application of advanced statistics to research data. The first cohort of five postdoctoral scholars were trained at UZ and UB, between 2016 and 2019. Through the formalized postdoctoral training approach, scholars identified areas of focus. In 2017, one of the scholars obtained a National Institutes of Health (NIH) Emerging Global Leader Award and is now a highly-rated researcher based in South Africa. A second scholar made NIH D43 and K43 grant applications, while the remaining three are academicians and early researchers at UZ. Although research output in Africa and many LMICs is low, it can be built through cooperation similar to the UZ-UB HRTP. This manuscript reports on an effort aimed at building individual and institutional research capacity in Zimbabwe. This can serve as a model for building other similar training programs.

Boceprevir and Antiretroviral Pharmacokinetic Interactions in HIV/HCV Co-infected Persons: AIDS Clinical Trials Group Study A5309s.

OBJECTIVE: The objective of this study was to determine the magnitude of drug interactions between the hepatitis C virus (HCV) protease inhibitor boceprevir (BOC) and antiretroviral (ARV) agents in persons with HIV/HCV co-infection. METHODS: Participants taking two nucleos(t)ide analogs with either efavirenz, raltegravir, or ritonavir-boosted atazanavir, darunavir, or lopinavir underwent intensive pharmacokinetic (PK) sampling for ARV 2 weeks before (week 2) and 2 weeks after initiating BOC (week 6) and for BOC at week 6. Geometric mean ratios (GMRs) and 90% confidence intervals (CIs) were used to compare ARV PK at weeks 2 and 6 and BOC PK at week 6 to historical data (HD) in healthy volunteers and HCV mono-infected patients. RESULTS: ARV PK was available for 55 participants. BOC reduced atazanavir and darunavir exposures by 30 and 42%, respectively. BOC increased raltegravir maximum concentration (C max) by 71%. BOC did not alter efavirenz PK. BOC PK was available for 53 participants. BOC exposures were similar in these HIV/HCV co-infected participants compared with HD in healthy volunteers, but BOC minimum concentrations (C min) were lower with all ARV agents (by 34-73%) compared with HD in HCV mono-infected patients. CONCLUSIONS: Effects of BOC on ARV PK in these HIV/HCV co-infected individuals were similar to prior studies in healthy volunteers. However, some differences in the effects of ARV on BOC PK were observed, indicating the magnitude of interactions may differ in HCV-infected individuals versus healthy volunteers. Findings highlight the need to conduct interaction studies with HCV therapies in the population likely to receive the combination.

Ultra-performance liquid chromatography tandem mass spectrometry for determination of Direct Acting Antiviral drugs in human liver fine needle aspirates.

An ultra-performance liquid chromatography with triple quadrupole mass spectrometry method was developed and validated for the determination of direct acting antiviral drug concentrations in human liver fine needle aspirates. Liver fine needle aspirate (FNA) biopsy samples were homogenized in acetonitrile to stabilize the analytes and precipitate protein. The acetonitrile supernatants were diluted with internal standards and mobile phase. Separation was achieved with a Waters Acquity BEH C18 column (50×2.1mm, 1.7um) with a gradient elution of 0.1% formic acid in water and acetonitrile. The total run time was 4.25min. Detection of analytes was achieved using electrospray ionization (positive mode) and triple quadrupole selected reaction monitoring. Standard curve concentrations ranged from 12.5 to 5000ng/mL for dasabuvir and the m1 metabolite of dasabuvir, 1.25 to 2500ng/mL for ombitasvir and ritonavir, and 5.00 to 5000ng/mL for paritaprevir. The intra- and inter-day accuracy and precision were less than 13.7% in low, medium, and high quality control samples. The validated method was applied to the analysis of a liver fine needle aspirate of a patient undergoing direct acting antiviral therapy for hepatitis C virus.

Paritaprevir and Ritonavir Liver Concentrations in Rats as Assessed by Different Liver Sampling Techniques.

The liver is crucial to pharmacology, yet substantial knowledge gaps exist in the understanding of its basic pharmacologic processes. An improved understanding for humans requires reliable and reproducible liver sampling methods. We compared liver concentrations of paritaprevir and ritonavir in rats by using samples collected by fine-needle aspiration (FNA), core needle biopsy (CNB), and surgical resection. Thirteen Sprague-Dawley rats were evaluated, nine of which received paritaprevir/ritonavir at 30/20 mg/kg of body weight by oral gavage daily for 4 or 5 days. Drug concentrations were measured using liquid chromatography-tandem mass spectrometry on samples collected via FNA (21G needle) with 1, 3, or 5 passes (FNA1, FNA3, and FNA5); via CNB (16G needle); and via surgical resection. Drug concentrations in plasma were also assessed. Analyses included noncompartmental pharmacokinetic analysis and use of Bland-Altman techniques. All liver tissue samples had higher paritaprevir and ritonavir concentrations than those in plasma. Resected samples, considered the benchmark measure, resulted in estimations of the highest values for the pharmacokinetic parameters of exposure (maximum concentration of drug in serum [Cmax] and area under the concentration-time curve from 0 to 24 h [AUC0-24]) for paritaprevir and ritonavir. Bland-Altman analyses showed that the best agreement occurred between tissue resection and CNB, with 15% bias, followed by FNA3 and FNA5, with 18% bias, and FNA1 and FNA3, with a 22% bias for paritaprevir. Paritaprevir and ritonavir are highly concentrated in rat liver. Further research is needed to validate FNA sampling for humans, with the possible derivation and application of correction factors for drug concentration measurements.

Development and validation of a UPLC-MS/MS method for the simultaneous determination of paritaprevir and ritonavir in rat liver.

AIM: Determination of paritaprevir and ritonavir in rat liver tissue samples. RESULTS: We successfully validated a UPLC-MS/MS method to measure paritaprevir and ritonavir in rat liver using deuterated internal standards (d8-paritapervir and d6-ritonavir). The method is linear from 20 to 20,000 and 5 to 10,000 pg on column for paritaprevir and ritonavir, respectively, and is normalized per milligram tissue. Interday and intraday variability ranged from 0.591 to 5.33% and accuracy ranged from -6.68 to 10.1% for quality control samples. The method was then applied to the measurement of paritaprevir and ritonavir in rat liver tissue samples from a pilot study. CONCLUSION: The validated method is suitable for measurement of paritaprevir and ritonavir within rat liver tissue samples for PK studies.

Lipid-Lowering Therapy in HIV-Infected Patients: Relationship with Antiretroviral Agents and Impact of Substance-Related Disorders.

BACKGROUND: The use of combination antiretroviral therapy (cART) has significantly decreased the morbidity and mortality associated with human immunodeficiency virus (HIV) infection. Lipid disorders, including lipodystrophy, hypertriglyceridemia, and hypercholesterolemia, remain the most commonly reported metabolic disorders among those treated with long-term cART. Mounting evidence suggests an association between drug abuse and poor glycemic control and diabetes complications. Substance related disorders (SRD) may increase the risk of metabolic syndrome. MATERIALS AND METHODS: The aim of this retrospective cohort study was to examine the relationship between SRD, cART, and lipid-lowering agent use in an HIV infected population. Patients received efavirenz or protease inhibitor-based cART for at least 6 months. Prescription information was retrieved from the medical records. The primary outcome was the use of lipid-lowering agents including statins, fibrates and fish oil. The impact of SRD and cART was assessed on the lipid-lowering agent use. RESULTS: A total of 276 subjects with HIV infection were included, 90 (33%) received lipid-lowering agents, and 31 (34%) had SRD. Smoking was prevalent among subjects with SRD (84 vs 15%, p<0.001). Statins were the mainstay for the management of dyslipidemia (66%), followed by the fibrates (24%), omega-3 fatty acids (5%), nicotinic acid (3%) and the cholesterol absorption inhibitors (3%). Use of statins or fibrates was significantly higher among subjects without SRD than those with (40 vs 23%, p=0.005). The type of cART, including efavirenz and protease inhibitors, appeared to have no significant impact on the use pattern of lipid-lowering agents. Lopinavir/ritonavir (lopinavir/r) was mostly prescribed for subjects with SRD (25 vs 8%, p=0.02). CONCLUSION: Among HIV-infected patients, statins remain the mainstay for the management of dyslipidemia in routine clinical care, followed by fibrates. A significant high risk of metabolic disorders among patients with SRD is implicated by heavy tobacco use and prevalent lopinavir/r-based treatment. Significantly low rate of lipid-lowering agent use in this population underscores the importance of lipid disorder scrutiny and cART treatment optimization for HIV-infected patients with SRD.

Adding value to antiretroviral proficiency testing.

BACKGROUND: Clinical trial specimens tested for antiretroviral (ARV) concentrations often require compliance with Clinical Laboratory Improvement Act and/or the Food and Drug Administration bioanalytical guidance. EXPERIMENTAL: The Clinical Pharmacology Quality Assurance Program (CPQA) designed 8 proficiency testing (PT) rounds over 4 years to assess precision, specificity and stability. RESULTS: Ten laboratories provided blinded proficiency data to support continued acceptable precision of ARV methods. Specificity samples identified little bias for individual methods; hemolyzed (87%) and lipemic (86%) results were ≤ 10% of their control results. Stability was established for ARVs in plasma at -70°C for 2.5-3.6 years. CONCLUSION: PT provided by the CPQA assured continued acceptability of individual laboratory assay performances for precision and specificity, and obtained ARV stability during long term storage.

Interaction of disulfiram with antiretroviral medications: efavirenz increases while atazanavir decreases disulfiram effect on enzymes of alcohol metabolism.

BACKGROUND AND OBJECTIVES: Alcohol abuse complicates treatment of HIV disease and is linked to poor outcomes. Alcohol pharmacotherapies, including disulfiram (DIS), are infrequently utilized in co-occurring HIV and alcohol use disorders possibly related to concerns about drug interactions between antiretroviral (ARV) medications and DIS. METHOD: This pharmacokinetics study (n=40) examined the effect of DIS on efavirenz (EFV), ritonavir (RTV), or atazanavir (ATV) and the effect of these ARV medications on DIS metabolism and aldehyde dehydrogenase (ALDH) activity which mediates the DIS-alcohol reaction. RESULTS: EFV administration was associated with decreased S-Methyl-N-N-diethylthiocarbamate (DIS carbamate), a metabolite of DIS (p=.001) and a precursor to the metabolite responsible for ALDH inhibition, S-methyl-N,N-diethylthiolcarbamate sulfoxide (DETC-MeSO). EFV was associated with increased DIS inhibition of ALDH activity relative to DIS alone administration possibly as a result of EFV-associated induction of CYP 3A4 which metabolizes the carbamate to DETC-MeSO (which inhibits ALDH). Conversely, ATV co-administration reduced the effect of DIS on ALDH activity possibly as a result of ATV inhibition of CYP 3A4. DIS administration had no significant effect on any ARV studied. DISCUSSION/CONCLUSIONS: ATV may render DIS ineffective in treatment of alcoholism. FUTURE DIRECTIONS: DIS is infrequently utilized in HIV-infected individuals due to concerns about adverse interactions and side effects. Findings from this study indicate that, with ongoing clinical monitoring, DIS should be reconsidered given its potential efficacy for alcohol and potentially, cocaine use disorders, that may occur in this population.

Clinical pharmacology quality assurance program: models for longitudinal analysis of antiretroviral proficiency testing for international laboratories.

Among National Institutes of Health HIV Research Networks conducting multicenter trials, samples from protocols that span several years are analyzed at multiple clinical pharmacology laboratories (CPLs) for multiple antiretrovirals. Drug assay data are, in turn, entered into study-specific data sets that are used for pharmacokinetic analyses, merged to conduct cross-protocol pharmacokinetic analysis, and integrated with pharmacogenomics research to investigate pharmacokinetic-pharmacogenetic associations. The CPLs participate in a semiannual proficiency testing (PT) program implemented by the Clinical Pharmacology Quality Assurance program. Using results from multiple PT rounds, longitudinal analyses of recovery are reflective of accuracy and precision within/across laboratories. The objectives of this longitudinal analysis of PT across multiple CPLs were to develop and test statistical models that longitudinally: (1) assess the precision and accuracy of concentrations reported by individual CPLs and (2) determine factors associated with round-specific and long-term assay accuracy, precision, and bias using a new regression model. A measure of absolute recovery is explored as a simultaneous measure of accuracy and precision. Overall, the analysis outcomes assured 97% accuracy (±20% of the final target concentration of all (21) drug concentration results reported for clinical trial samples by multiple CPLs). Using the Clinical Laboratory Improvement Act acceptance of meeting criteria for ≥2/3 consecutive rounds, all 10 laboratories that participated in 3 or more rounds per analyte maintained Clinical Laboratory Improvement Act proficiency. Significant associations were present between magnitude of error and CPL (Kruskal-Wallis P < 0.001) and antiretroviral (Kruskal-Wallis P < 0.001).

Sex differences in cyclosporine pharmacokinetics and ABCB1 gene expression in mononuclear blood cells in African American and Caucasian renal transplant recipients.

Cyclosporine exhibits pharmacokinetic and pharmacodynamic variability in renal transplant recipients (RTR) attributed to P-glycoprotein (P-gp), an ABCB1 efflux transporter that influences bioavailability and intracellular distribution. Data on race and sex influences on P-gp in RTR are lacking. We investigated sex and race influences on cyclosporine pharmacokinetics and ABCB1 gene expression in peripheral blood mononuclear cells (PBMC). Fifty-four female and male African American and Caucasian stable RTR receiving cyclosporine and mycophenolic acid completed a 12-hour study. ABCB1 gene expression was assessed in PBMCs pre-dose and 4 hours after cyclosporine. Statistical analysis used mixed effects models on transformed, normalized ABCB1 expression and cyclosporine pharmacokinetics. Sex and race differences were observed for the dose-normalized area under the concentration curve (AUC0-12 /Dose) [P = .0004], apparent clearance [P = .0004] and clearance/body mass index (CL/BMI) [P = .027] with slowest clearance and greatest drug exposure in females. Sex and race differences were found pre-dose and 4 hours for ABCB1 [P < .0001] with females having less expression than males. ABCB1 differences were observed between pre-dose and 4 hours [P = .0009]. Female RTR had slower cyclosporine clearance and lower ABCB1 gene expression in PBMC suggesting reduced efflux activity and greater intracellular drug exposure.

Pharmacokinetic interactions of CEP-1347 and atazanavir in HIV-infected patients.

CEP-1347 is a potent inhibitor of mixed lineage kinase (MLK), which was investigated for ameliorating HIV-associated neurocognitive disorders. CEP-1347 and atazanavir pharmacokinetics were determined when CEP-1347 50 mg twice daily was administered to HIV-infected patients (n = 20) receiving combination antiretroviral therapy including atazanavir and ritonavir (ATV/RTV, 300/100 mg) once daily continuously. Co-administration of CEP-1347 and ATV/RTV resulted with significant changes in pharmacokinetics of ATV but not RTV. Specifically, an increase in ATV accumulation ratio of 15 % (p = 0.007) and a prolongation of T(½) from 12.7 to 15.9 h (p = 0.002) were observed. The results suggested that co-administration of CEP-1347 with ATV/RTV in HIV-infected patients might result in limited impact on ATV but not on RTV pharmacokinetics.

Discordant associations between SLCO1B1 521T→C and plasma levels of ritonavir-boosted protease inhibitors in AIDS clinical trials group study A5146.

OBJECTIVE: Among HIV-positive patients prescribed ritonavir-boosted lopinavir, SLCO1B1 521T→C (rs4149056) is associated with increased plasma lopinavir exposure. Protease inhibitors (PIs) are also substrates for cytochrome P450 (CYP) 3A and ABCB1, which are induced by NR1I2. We characterized relationships between ABCB1, CYP3A4, CYP3A5, NR1I2, and SLCO1B1 polymorphisms and trough PI concentrations among AIDS Clinical Trials Group study A5146 participants. METHODS: At study entry, subjects with virologic failure on PI-containing regimens initiated new ritonavir-boosted PI regimens. We studied associations between week 2 PI plasma trough concentrations and 143 polymorphisms in these genes, including 4 targeted polymorphisms. RESULTS: Among 275 subjects with both drug concentrations and genetic data, allelic frequencies of SLCO1B1 521T→C were 15%, 1%, and 8% in whites, blacks, and Hispanics, respectively. Further analyses were limited to 268 white, black, or Hispanic subjects who initiated ritonavir-boosted lopinavir (n = 98), fosamprenavir (n = 69), or saquinavir (n = 99). Of targeted polymorphisms, SLCO1B1 521T→C tended to be associated with higher lopinavir concentrations, with a 1.38-fold increase in the mean per C allele (95% confidence interval, 0.97-1.96; n = 98; P = 0.07). With fosamprenavir, SLCO1B1 521T→C was associated with lower amprenavir concentrations, with a 35% decrease in the mean per C allele (geometric mean ratio 0.65; 95% confidence interval, 0.44-0.94; n = 69; adjusted P = 0.02). There was no significant association with saquinavir concentrations, and none of the remaining 139 exploratory polymorphisms were statistically significant after correcting for multiple comparisons. CONCLUSIONS: With ritonavir-boosted PIs, a SLCO1B1 polymorphism that predicts higher lopinavir trough concentrations seems to predict lower amprenavir trough concentrations. The mechanism underlying this discordant association is uncertain.

Race and drug formulation influence on mycophenolic acid pharmacokinetics in stable renal transplant recipients.

BACKGROUND: Limited mycophenolic acid (MPA) data are available comparing racial influence on mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS) pharmacokinetics. METHODS: Intrapatient MPA pharmacokinetics of MMF versus EC-MPS were compared in 13 male African American (AA) and 14 Caucasian (C) renal transplant recipients (RTRs). RTRs were switched to equivalent doses of the alternate formulation for at least 10 days prior to the second study. Mycophenolic acid clearance and dose-normalized area under the concentration-time curve(0-12) (AUC*) were determined. Mixed model statistics evaluated the main effects of race, drug formulation, and interaction of race and drug formulation (R × D) with albumin, cyclosporine trough, renal function, and diabetes and enterhepatic recirculation. RESULTS: Significant R × D was identified for MPA AUC* for EC-MPS (AA, 0.056 ± 0.029 [mg·h/L]/mg; C, 0.080 ± 0.044 [mg·h/L]/mg) compared with MMF (AA, 0.053 ± 0.019 [mg·h/L]/mg; C, 0.060 ± 0.025 [mg·h/L]/mg), P = .022. Significant R × D was identified with albumin in the model for MPA clearance for MMF (AA, 21.7 ± 8.9 L/h; C, 20.5 ± 10.8 L/h) compared with EC-MPS (AA, 22.2 ± 10.1 L/h; C, 16.2 ± 9.1 L/h), P = .032. CONCLUSIONS: Race influences MPA exposure between MMF and EC-MPS and may warrant therapeutic monitoring during formulation conversion.

Antiretroviral bioanalysis methods of tissues and body biofluids.

Research in the many areas of HIV treatment, eradication and prevention has necessitated measurement of antiretroviral (ARV) concentrations in nontraditional specimen types. To determine the knowledgebase of critical details for accurate bioanalysis, a review of the literature was performed and summarized. Bioanalytical assays for 31 ARVs, including metabolites, were identified in 205 publications measuring various tissues and biofluids. 18 and 30% of tissue or biofluid methods, respectively, analyzed more than one specimen type; 35-37% of the tissue or biofluid methods quantitated more than one ARV. 20 and 76% of tissue or biofluid methods, respectively, were used for the analysis of human specimens. HPLC methods with UV detection predominated, but chronologically MS detection began to surpass. 40% of the assays provided complete intra- and inter-assay validation data, but only 9% of publications provided any stability data with even less for the prevalent ARV in treatments.

Therapeutic drug monitoring of protease inhibitors and efavirenz in HIV-infected individuals with active substance-related disorders.

BACKGROUND: Achieving targeted antiretroviral (ARV) plasma concentrations during long-term treatment in human immunodeficiency virus (HIV)-infected patients with substance-related disorders (SRDs) may be challenging due to a number of factors, including medication adherence, coinfection with hepatitis B or C virus, medication intolerance, and drug interactions. One approach to investigate these factors is to conduct therapeutic drug monitoring to measure ARV exposure during treatment. The objective of this study was to utilize therapeutic drug monitoring to compare efavirenz (EFV) and protease inhibitor pharmacokinetics in patients with and without SRDs. METHODS: This was a multicenter, cross-sectional open-label study in patients with HIV-1 infection receiving antiretroviral therapy (ART), with active (n=129) or without (n=146) SRD according to National Institute on Drug Abuse criteria. Two hundred seventy-five subjects who were receiving either protease inhibitor-based or EFV-based ART regimens for >6 months were enrolled at 4 HIV treatment centers with an equal distribution of SRD and non-SRD at each site. The patients were instructed during enrollment visits with regard to the importance of adherence before and after study visits. Demographics and routine clinical laboratory tests were recorded. RESULTS: Among the 275 patients, 47% had SRD with at least 1 substance. There were no significant differences between SRD and non-SRD groups for race, gender, age, or CD4 count at entry. A significantly higher proportion of patients with SRD had an entry HIV RNA plasma concentration>75 copies per milliliter compared with patients without SRD (40% vs 28%, P=0.044). Logistic regression modeling revealed an association between HIV RNA plasma concentration and African American race (P=0.017). A significantly higher proportion of SRDs also had an EFV or protease inhibitor trough concentration below the desired range (23% vs 9%, P=0.048). Significantly lower trough concentrations were noted in patients with SRDs receiving atazanavir (0.290 vs 0.976 µg/mL) or lopinavir (3.75 vs 5.30 µg/mL). CONCLUSIONS: The pharmacokinetic data indicate differences between HIV-infected patients with and without SRDs that may influence viral load suppression during long-term ART. These findings require additional investigation in a randomized design with more intensive pharmacokinetic assessment to identify individual factors that are contributing to suboptimal ARV exposure in patients with SRDs.