Magister Pharmaceuticae - MPharm / The growing resistance of Methicillin-Resistant Staphylococcus aureus (MRSA) to currently prescribed drugs has resulted in the failure of prevention and treatment of different infections caused by the superbug. Therefore, to keep pace with the resistance, there is a pressing need for novel antimicrobial agents, especially from non-conventional sources. Several natural products (NPs) have displayed varying in vitro activities against the pathogen but few of these natural compounds have been studied for their prospects to be potential antimicrobial drug candidates. This may be due to the high cost, tedious, and time-consuming process of conducting the important preclinical tests on these compounds. Hence, there is a need for cost-effective strategies for mining the available data on these natural compounds. This would help to get the knowledge that may guide rational prioritization of “likely to succeed” natural compounds to be developed into potential antimicrobial drug candidates.

Background The lack of methadone pharmacokinetic data in children and neonates restrains dosing to achieve the target concentration in these populations. A minimum effective analgesic concentration of methadone in opioid naïve adults is 0.058 mg·l-1, while no withdrawal symptoms were observed in neonates suffering opioid withdrawal if plasma concentrations of methadone were above 0.06 mg·l-1. The racemate of methadone which is commonly used in pediatric and anesthetic care is metabolized to 2-ethylidine-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenylpyrroline (EMDP). Methods Data from four studies (age 33-week PMA-15 years) were pooled (n = 56) for compartment analysis using nonlinear mixed effects modeling. Parameter estimates were standardized to a 70-kg person using an allometric model approach. Investigation was made of the racemate and metabolite (EDDP and EMDP) dispositions. In addition, neonatal data (n = 7) allowed further study of R- and S-enantiomer pharmacokinetics. Results A three-compartment linear disposition model best described the observed time-concentration profiles with additional compartments for metabolites. Population parameter estimates (between-subject variability) were central volume (V1) 21.5 (29%) l·70 kg-1, peripheral volumes of distribution V2 75.1 (23%) l·70 kg-1 and V3 484 (8%) l·70 kg -1, clearance (CL) 9.45 (11%)l·h-1·70 kg-1, and intercompartment clearances Q2 325 (21%) l·h -1·70 kg-1 and Q3 136 (14%) l·h -1·70 kg-1. EDDP formation clearance was 9.1 (11%) l·h-1·70 kg-1, formation clearance of EMDP from EDDP 7.4 (63%)l·h-1·70 kg-1, elimination clearance of EDDP was 40.9 (26%) l·h-1·70 kg-1 and the rate constant for intermediate compartments 2.17 (43%) h-1. Conclusions Current pharmacokinetic parameter estimates in children and neonates are similar to those reported in adults. There was no clearance maturation with age. Neonatal enantiomer clearances were similar to those described in adults. A regimen of 0.2 mg·kg-1 per 8 h in neonates achieves a target concentration of 0.06 mg·l-1 within 36 h. Infusion, rather than intermittent dosing, should be considered if this target is to be achieved in older children after cardiac surgery.

These studies examined the in vivo pharmacokinetics and efficacy of five anti-methamphetamine monoclonal antibodies (mAbs, KD values from 11 to 250 nM) in rats. While no substantive differences in mAb systemic clearance (t1/2 = 6.1-6.9 days) were found, in vivo function was significantly reduced within 1-3 days for four of the five mAbs. Only mAb4G9 was capable of prolonged efficacy, as judged by prolonged high methamphetamine serum concentrations. MAb4G9 also maintained high amphetamine serum concentrations, along with reductions in methamphetamine and amphetamine brain concentrations, indicating neuroprotection. The combination of broad specificity for methamphetamine-like drugs, high affinity, and prolonged action in vivo suggests mAb4G9 is a potentially efficacious medication for treating human methamphetamine-related medical diseases.

A highly sensitive and rapid method for the analysis of isradipine in human plasma using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed. The procedure involves a simple liquid-liquid extraction of isradipine and amlodipine (IS, internal standard) with methyl-t-butyl ether after alkaline treatment and separation by RP-HPLC. Detection was performed by positive ion electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode, monitoring the transitions m/z 372.1 → m/z 312.2 and m/z 408.8 → m/z 237.9, for quantification of isradipine and IS, respectively. The standard calibration curves showed good linearity within the range of 10 to 5000 pg/mL (r2 ≥ 0.9998). The lower limit of quantitation (LLOQ) was 10 pg/mL. The retention times of isradipine (0.81 min) and IS (0.65 min) suggested the potential for high throughput of the proposed method. In addition, no significant metabolic compounds were found to interfere with the analysis. This method offered good precision and accuracy and was successfully applied for the pharmacokinetic and bioequivalence studies of 5 mg of sustained-release isradipine in 24 healthy Korean volunteers.

Background: Aceclofenac is a phenylacetic acid derivative with analgesic and anti-inflammatory properties and an improved gastrointestinal tolerance compared with other NSAIDs, such as diclofenac. Objective: This study was conducted to compare the bioavailability of 2 branded formulations of aceclofenac 100 mg (test and reference) marketed in Korea. Methods: This single-dose, randomized, open-label, 2-period crossover study in healthy Korean adult volunteers was conducted at Hanyang University Medical Center (Seoul, Republic of Korea). Subjects received 1 tablet of each aceclofenac 100-mg formulation. Study drugs were administered with 240 mL of water after a 10-hour overnight fast on each of 2 treatment days separated by a 1-week washout period. After study drug administration, serial blood samples were collected over a period of 12 hours. Plasma was analyzed for aceclofenac concentration using a validated high-performance liquid chromatography method with visible detection in the range of 0.1 to 20 μg/mL, with a lower limit of quantitation of 0.1 μg/mL. Several pharmacokinetic (PK) parameters, including Cmax, Tmax, t1/2, AUC0-t, AUC0-∞, and ke, were determined from the plasma concentrations of the 2 aceclofenac formulations. Cmax, AUC0-t, and AUC0-∞ were used to test for bioequivalence after log-transformation of plasma data. The predetermined, regulatory range of 90% CI for bioequivalence was 0.80 to 1.25. Results: A total of 24 subjects were enrolled (20 men, 4 women; mean [SD] age, 23.5 [1.4] years; mean [SD] weight, 68.1 [11.5] kg). No significant differences were found based on analysis of variance, with mean values and 90% CIs of test/reference ratios for these parameters as follows: Cmax, 10.57 versus 9.79 μg/mL (0.961-1.225); AUC0-t, 19.95 versus 19.93 μg · h/mL (0.937-1.037); and AUC0-∞, 20.75 versus 20.48 μg · h/mL (0.949-1.049). Conclusion: In these healthy Korean volunteers, results from the PK analysis suggested that the test and reference formulations of aceclofenac 100-mg tablets were bioequivalent, based on the regulatory definition.

Chronic arthritis adversely affects glomerular function and nonsteroidal anti-inflammatory drugs (NSAIDs) reduce electrolyte urinary excretion. In addition, both acute and chronic inflammations may alter clearance of drugs. We studied (a) the effects of inflammation on the renal function and pharmacokinetics of rofecoxib and meloxicam; (b) whether inflammation could exacerbate reduced electrolytes excretion changes observed with NSAIDs; and (c) the influence of inflammation on distribution of these drugs into the kidney. Single oral doses of rofecoxib (10 mg kg-1), meloxicam (3 mg kg -1) or placebo were administered to normal or pre-adjuvant arthritic rats. Blood and urine samples were collected for the measurement of plasma nitrite, BUN and creatinine. The urinary excretion of sodium and potassium was also determined. Nitrite, BUN and plasma creatinine were increased starting on day 9 in the groups with inflammation. Sodium and potassium excretion rates were not affected by inflammation. Meloxicam did not alter the electrolyte excretion in any of the groups. Rofecoxib significantly decreased sodium and potassium excretion in normal rats and potassium excretion in inflamed rats. Inflammation significantly increased plasma concentrations of rofecoxib, but not meloxicam. The ratios of the kidney:plasma concentrations were not significantly altered by inflammation following either drug. Inflammation altered kidney function, demonstrated by increases in BUN and plasma creatinine. However, it did not influence the urinary electrolytes excretion. Since we have observed similar patterns of the effect of NSAIDs on kidney under healthy and inflammatory conditions, one may conclude that inflammation does not exacerbate the adverse effect.

Glucans are microbial cell wall carbohydrates that are shed into the circulation of patients with infections. Glucans are immunomodulatory and have structures that are influenced by bacterial or fungal species and growth conditions. We developed a method to covalently label carbohydrates with a fluorophore on the reducing terminus, and used the method to study the pharmacokinetics following intravenous administration of three highly purified and characterized glucans (glucan phosphate, laminarin and scleroglucan) that varied according to molecular size, branching frequency and solution conformation. Elimination half-life was longer (3.8±0.8 vs. 2.6±0.2 and 3.1±0.6 h) and volume of distribution lower (350±88 ml/kg vs. 540±146 and 612±154 ml/kg) for glucan phosphate than for laminarin and scleroglucan. Clearance was lower for glucan phosphate (42±6 ml/kg h) than for laminarin (103±17 ml/kg h) and scleroglucan (117±19 ml/kg h). Since plasma levels at steady state are inversely related to clearance, these differences suggest that pharmacokinetics could favor higher blood levels of glucans with certain physicochemical properties.

Indiana University-Purdue University Indianapolis (IUPUI) / Polypharmacy leads to increased risk of drug-drug interactions (DDI’s). In this dissertation, we create a database for quantifying fraction of metabolism (fm) of CYP450 isozymes for FDA approved drugs. A reproducible data collection protocol was developed to extract key information from publicly available in vitro selective CYP enzyme inhibition studies. The fm was then estimated from the curated data. Then, proposed a random control selection approach for nested case-control design for electronical health records (HER) and electronical medical records (EMR) databases. By relaxing the matching by case’s index time restriction, random control dramatically reduces the computational burden compared with traditional control selection approaches. Using the Observational Medical Outcomes Partnership gold standard and an EMR database, random control is demonstrated to have better performances as well. Finally, combining epidemiological studies and pharmacokinetic modeling with fm database, we detected and evaluated high-dimensional drug-drug interactions among thirty high frequency drugs. Multi-drug combinations that increased risk of myopathy were identified in the FAERS and EMR databases by a mixture drug-count response model (MDCM) model. Twenty-eight 3-way and 43 4-way DDI’s increased ratio of area under plasma concentration–time curve (AUCR) >2-fold and had significant myopathy risk in both databases. The predicted AUCR of omeprazole in the presence of fluconazole and clonidine was 9.35; and increased risk of myopathy was 6.41 (LFDR = 0.002) in FAERS and 18.46 (LFDR = 0.005) in EMR. We demonstrate that combining health record informatics and pharmacokinetic modeling is a powerful translational approach to detect high-dimensional DDI’s. / 2 years

No description available.

It was the objective of the current study to evaluate the ability of 10-fold cross validation and prediction error sum of squares (PRESS) statistic to identify population pharmacokinetic models (PPKM) that were estimated from data without influence observations versus PPKMs from data containing influence observations. The evaluation of 10-fold cross validation and PRESS statistic from Leave-one-out cross-validation for PPK model validation was performed in 3 Phases. In Phase 1 model parameters (theta and clearance) were estimated for datasets with and without influence observations. It was found that influence observations caused an over-estimation of the model parameters.