Displaying publications 1 - 20 of 25 in total

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  1. Tang BH, Zhang JY, Allegaert K, Hao GX, Yao BF, Leroux S, et al.
    Clin Pharmacokinet, 2023 Aug;62(8):1105-1116.
    PMID: 37300630 DOI: 10.1007/s40262-023-01265-z
    BACKGROUND AND OBJECTIVE: High variability in vancomycin exposure in neonates requires advanced individualized dosing regimens. Achieving steady-state trough concentration (C0) and steady-state area-under-curve (AUC0-24) targets is important to optimize treatment. The objective was to evaluate whether machine learning (ML) can be used to predict these treatment targets to calculate optimal individual dosing regimens under intermittent administration conditions.

    METHODS: C0 were retrieved from a large neonatal vancomycin dataset. Individual estimates of AUC0-24 were obtained from Bayesian post hoc estimation. Various ML algorithms were used for model building to C0 and AUC0-24. An external dataset was used for predictive performance evaluation.

    RESULTS: Before starting treatment, C0 can be predicted a priori using the Catboost-based C0-ML model combined with dosing regimen and nine covariates. External validation results showed a 42.5% improvement in prediction accuracy by using the ML model compared with the population pharmacokinetic model. The virtual trial showed that using the ML optimized dose; 80.3% of the virtual neonates achieved the pharmacodynamic target (C0 in the range of 10-20 mg/L), much higher than the international standard dose (37.7-61.5%). Once therapeutic drug monitoring (TDM) measurements (C0) in patients have been obtained, AUC0-24 can be further predicted using the Catboost-based AUC-ML model combined with C0 and nine covariates. External validation results showed that the AUC-ML model can achieve an prediction accuracy of 80.3%.

    CONCLUSION: C0-based and AUC0-24-based ML models were developed accurately and precisely. These can be used for individual dose recommendations of vancomycin in neonates before treatment and dose revision after the first TDM result is obtained, respectively.

    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  2. Colin PJ, Allegaert K, Thomson AH, Touw DJ, Dolton M, de Hoog M, et al.
    Clin Pharmacokinet, 2019 06;58(6):767-780.
    PMID: 30656565 DOI: 10.1007/s40262-018-0727-5
    BACKGROUND AND OBJECTIVES: Uncertainty exists regarding the optimal dosing regimen for vancomycin in different patient populations, leading to a plethora of subgroup-specific pharmacokinetic models and derived dosing regimens. We aimed to investigate whether a single model for vancomycin could be developed based on a broad dataset covering the extremes of patient characteristics. Furthermore, as a benchmark for current dosing recommendations, we evaluated and optimised the expected vancomycin exposure throughout life and for specific patient subgroups.

    METHODS: A pooled population-pharmacokinetic model was built in NONMEM based on data from 14 different studies in different patient populations. Steady-state exposure was simulated and compared across patient subgroups for two US Food and Drug Administration/European Medicines Agency-approved drug labels and optimised doses were derived.

    RESULTS: The final model uses postmenstrual age, weight and serum creatinine as covariates. A 35-year-old, 70-kg patient with a serum creatinine level of 0.83 mg dL-1 (73.4 µmol L-1) has a V1, V2, CL and Q2 of 42.9 L, 41.7 L, 4.10 L h-1 and 3.22 L h-1. Clearance matures with age, reaching 50% of the maximal value (5.31 L h-1 70 kg-1) at 46.4 weeks postmenstrual age then declines with age to 50% at 61.6 years. Current dosing guidelines failed to achieve satisfactory steady-state exposure across patient subgroups. After optimisation, increased doses for the Food and Drug Administration label achieve consistent target attainment with minimal (± 20%) risk of under- and over-dosing across patient subgroups.

    CONCLUSIONS: A population model was developed that is useful for further development of age and kidney function-stratified dosing regimens of vancomycin and for individualisation of treatment through therapeutic drug monitoring and Bayesian forecasting.

    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics*
  3. Ooi MH, Ngu SJ, Chor YK, Li J, Landersdorfer CB, Nation RL
    Clin Infect Dis, 2019 11 13;69(11):1962-1968.
    PMID: 30722017 DOI: 10.1093/cid/ciz067
    BACKGROUND: Intravenous colistin is widely used to treat infections in pediatric patients. Unfortunately, there is a paucity of pharmacological information to guide the selection of dosage regimens. The daily dose recommended by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) is the same body weight-based dose traditionally used in adults. The aim was to increase our understanding of the patient factors that influence the plasma concentration of colistin, and assess the likely appropriateness of the FDA and EMA dosage recommendations.

    METHODS: There were 5 patients, with a median age of 1.75 (range 0.1-6.25) years, a median weight of 10.7 (2.9-21.5) kg, and a median creatinine clearance of 179 (44-384) mL/min/1.73m2, who received intravenous infusions of colistimethate each 8 hours. The median daily dose was 0.21 (0.20-0.21) million international units/kg, equivalent to 6.8 (6.5-6.9) mg of colistin base activity per kg/day. Plasma concentrations of colistimethate and formed colistin were subjected to population pharmacokinetic modeling to explore the patient factors influencing the concentration of colistin.

    RESULTS: The median, average, steady-state plasma concentration of colistin (Css,avg) was 0.88 mg/L; individual values ranged widely (0.41-3.50 mg/L), even though all patients received the same body weight-based daily dose. Although the daily doses were ~33% above the upper limit of the FDA- and EMA-recommended dose range, only 2 patients achieved Css,avg ≥2mg/L; the remaining 3 patients had Css,avg <1mg/L. The pharmacokinetic covariate analysis revealed that clearances of colistimethate and colistin were related to creatinine clearance.

    CONCLUSIONS: The FDA and EMA dosage recommendations may be suboptimal for many pediatric patients. Renal functioning is an important determinant of dosing in these patients.

    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics*
  4. Das B, Sarkar C, Biswas R, Pandey S
    Pak J Pharm Sci, 2008 Jan;21(1):78-87.
    PMID: 18166524
    Glycopeptide antibiotics represent an important class of microbial compounds produced by several genera of actinomycetes. The emergence of resistance to glycopeptides among enterococci and staphylococci has prompted the search for second-generation drugs of this class and semi-synthetic derivatives are currently under clinical trials. Antimicrobial resistance among gram-positive organisms has been increasing steadily during the past several decades. Dalbavancin, a novel lipoglycopeptide, has a mechanism of action similar to that of other glycopeptides. It has in vitro activity against a variety of Gram-positive organisms specially multidrug resistant Staphylococcus aureus, but no activity against Gram-negative or vancomycin-resistant enterococci that possess vanA gene. Due to its prolonged half-life (6-10 days), dalbavancin can be administered intravenously once weekly. In Phase II and III clinical trials, dalbavancin was effective and well-tolerated for the treatment of skin and soft-tissue infections, catheter-related bloodstream infections, and skin and skin-structure infections. To date, adverse events have been mild and limited; the most common being pyrexia, headache, diarrhea. Dalbavancin appears to be a promising antimicrobial agent for the treatment of Gram-positive infections. Additional clinical data are required to fully assess its use. Despite the remarkable and favorable pharmacokinetic and pharmacodynamic properties, the use of this potent agent should be restricted to severe infections due to multidrug resistant organisms to limit the risk of selection of resistance. It is active against Gram-positive aerobes and anerobes, including resistant pathogens, with the exception of strains producing vanA-mediated resistance. Its approval by the FDA is expected soon. The extent to which dalbavancin will supplant vancomycin and whether it will be preferred over other newer agents such as linezolid in the next decade remains to be seen.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  5. Cheng V, Abdul-Aziz MH, Roberts JA, Shekar K
    Expert Opin Drug Metab Toxicol, 2019 Feb;15(2):103-112.
    PMID: 30582435 DOI: 10.1080/17425255.2019.1563596
    INTRODUCTION: One major challenge to achieving optimal patient outcome in extracorporeal membrane oxygenation (ECMO) is the development of effective dosing strategies in this critically ill patient population. Suboptimal drug dosing impacts on patient outcome as patients on ECMO often require reversal of the underlying pathology with effective pharmacotherapy in order to be liberated of the life-support device. Areas covered: This article provides a concise review of the effective use of antibiotics, analgesics, and sedative by characterizing the specific changes in PK secondary to the introduction of the ECMO support. We also discuss the barriers to achieving optimal pharmacotherapy in patients on ECMO and also the current and potential research that can be undertaken to address these clinical challenges. Expert opinion: Decreased bioavailability due to sequestration of drugs in the ECMO circuit and ECMO induced PK alterations are both significant barriers to optimal drug dosing. Evidence-based drug choices may minimize sequestration in the circuit and would enable safety and efficacy to be maintained. More work to characterize ECMO related pharmacodynamic alterations such as effects of ECMO on hepatic cytochrome system are still needed. Novel techniques to increase target site concentrations should also be explored.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  6. Jamal JA, Roberts DM, Udy AA, Mat-Nor MB, Mohamad-Nor FS, Wallis SC, et al.
    Int J Antimicrob Agents, 2015 Jul;46(1):39-44.
    PMID: 25881872 DOI: 10.1016/j.ijantimicag.2015.02.014
    Here we describe the pharmacokinetics of piperacillin administered by continuous infusion (CI) versus intermittent bolus (IB) dosing in critically ill patients receiving continuous venovenous haemofiltration (CVVH) and compare the frequency of pharmacodynamic/pharmacokinetic (PK/PD) target attainment with each dosing strategy. This was a prospective pharmacokinetic trial in 16 critically ill patients with severe sepsis or septic shock undergoing CVVH and randomised to receive either CI or IB administration of a standard daily dose of piperacillin/tazobactam (11.25g/day on Day 1 followed by 9g/day). Serial blood samples were measured on two occasions. Piperacillin pharmacokinetics were calculated using a non-compartmental approach. Blood concentrations were compared with established PK/PD targets. On occasion 1 (Days 1-3 of therapy), IB administration resulted in significantly higher piperacillin peak concentrations (169 vs. 89mg/L; P=0.002), whereas significantly higher steady-state concentrations were observed in CI patients (83 vs. 57mg/L; P=0.04). Total clearance and clearance not mediated by CVVH were significantly higher with CI administration [median (interquartile range), 1.0 (0.7-1.1) and 0.8 (0.6-1.0)mL/kg/min; P=0.001 and 0.001, respectively]. The estimated unbound piperacillin concentrations were four times above the target susceptibility breakpoint (16mg/L) for the entire dosing interval (100%fT>4xMIC) in 87.5% of patients receiving CI administration (sampling occasion 1), compared with 62.5% of IB patients achieving the desired target (50%fT>4xMIC). Compared with IB dosing, and despite similar CVVH settings, CI administration of piperacillin results in a pharmacokinetic profile that may optimise outcomes for less susceptible pathogens.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics*
  7. Jamal JA, Mat-Nor MB, Mohamad-Nor FS, Udy AA, Wallis SC, Lipman J, et al.
    Int J Antimicrob Agents, 2015 Jan;45(1):41-5.
    PMID: 25455853 DOI: 10.1016/j.ijantimicag.2014.09.009
    The objective of this study was to describe the pharmacokinetics of meropenem, administered by continuous infusion (CI) or intermittent bolus (IB), in critically ill patients receiving continuous venovenous haemofiltration (CVVH) and to evaluate the frequency of pharmacokinetic/pharmacodynamic target attainment with each dosing strategy. This was a prospective, randomised controlled trial in critically ill patients receiving CVVH and administered meropenem by CI or IB. Serial meropenem concentrations in plasma and ultrafiltrate were measured after administration of a standard total daily dose (4 g/day on Day 1, followed by 3g/day thereafter) on two occasions during antibiotic therapy. Meropenem pharmacokinetic parameters were calculated using a non-compartmental approach. Sixteen critically ill patients receiving CVVH concurrently treated with meropenem were randomised to CI (n = 8) or IB dosing (n = 8). IB administration resulted in higher maximum concentrations (C(max)) [64.7 (58.9-80.3) and 64.8 (48.5-81.8) mg/L, respectively] on both sampling occasions compared with CI (P < 0.01 and P = 0.04, respectively). CI resulted in a higher meropenem steady-state concentration (Css) on occasion 1 [26.0 (24.5-41.6) mg/L] compared with the minimum concentration (C(min)) observed for IB patients [17.0 (15.7-19.8)mg/L; P < 0.01]. CVVH contributed to ca. 50% of meropenem total clearance in these patients. The administered meropenem doses resulted in plasma drug concentrations that were >4× the targeted susceptibility breakpoint (2mg/L) for 100% of the dosing interval, for both groups, on both occasions. CI could be an alternative to IB for meropenem administration in critically ill patients receiving CVVH.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics*
  8. Ling SS, Magosso E, Khan NA, Yuen KH, Barker SA
    Drug Dev Ind Pharm, 2006 Mar;32(3):335-45.
    PMID: 16556538
    A liposome system was evaluated for oral delivery of a poorly bioavailable hydrophilic drug. The system was prepared from proliposome, which consisted of negatively charged phosphatidylcholine, whereas cefotaxime was chosen as the model drug. An in vivo study was carried out on nine rats according to a three-way crossover design to compare the oral bioavailability of cefotaxime from the liposomal formulation with that of an aqueous drug solution and a physical mixture of cefotaxime with blank liposomes. The results indicated that the extent of bioavailability of cefotaxime was increased approximately 2.7 and 2.3 times compared with that of the aqueous solution and the physical mixture, respectively. In a separate study, simultaneous determination of cefotaxime in intestinal lymph (collected from the mesenteric lymph duct) and in plasma (collected from the tail vein) revealed that its concentration was consistently higher in the lymph than in the plasma when administered via the liposomal formulation, whereas the reverse was observed with the aqueous solution. Thus, the results indicated that the liposomes system has the potential of increasing the oral bioavailability of poorly bioavailable hydrophilic drugs and also promote their lymphatic transport in the intestinal lymph.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics*
  9. Mohd Sazlly Lim S, Heffernan AJ, Zowawi HM, Roberts JA, Sime FB
    Eur J Clin Microbiol Infect Dis, 2021 Sep;40(9):1943-1952.
    PMID: 33884516 DOI: 10.1007/s10096-021-04252-z
    Due to limited treatment options for carbapenem-resistant Acinetobacter baumannii (CR-AB) infections, antibiotic combinations are commonly used. In this study, we explored the potential efficacy of meropenem-sulbactam combination (MEM/SUL) against CR-AB. The checkerboard method was used to screen for synergistic activity of MEM/SUL against 50 clinical CR-AB isolates. Subsequently, time-kill studies against two CR-AB isolates were performed. Time-kill data were described using a semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model. Subsequently, Monte Carlo simulations were performed to estimate the probability of 2-log kill, 1-log kill or stasis at 24-h following combination therapy. The MEM/SUL demonstrated synergy against 28/50 isolates. No antagonism was observed. The MIC50 and MIC90 of MEM/SUL were decreased fourfold, compared to the monotherapy MIC. In the time-kill studies, the combination displayed synergistic killing against both isolates at the highest clinically achievable concentrations. At concentrations equal to the fractional inhibitory concentration, synergism was observed against one isolate. The PK/PD model adequately delineated the data and the interaction between meropenem and sulbactam. The effect of the combination was driven by sulbactam, with meropenem acting as a potentiator. The simulations of various dosing regimens revealed no activity for the monotherapies. At best, the MEM/SUL regimen of 2 g/4 g every 8 h demonstrated a probability of target attainment of 2-log10 kill at 24 h of 34%. The reduction in the MIC values and the achievement of a moderate PTA of a 2-log10 reduction in bacterial burden demonstrated that MEM/SUL may potentially be effective against some CR-AB infections.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics*
  10. Islahudin F, Ong HY
    J Infect Dev Ctries, 2014 Oct;8(10):1267-71.
    PMID: 25313602 DOI: 10.3855/jidc.4676
    INTRODUCTION: Antibiotic resistance is a rapidly emerging problem. A major concern is methicillin-resistant Staphylococcus aureus (MRSA), especially in developing countries where cost-effectiveness is imperative. Restriction of vancomycin usage is necessary to reduce the emergence of vancomycin-resistant organisms. The aim of this study was to look into the appropriate use of vancomycin based on the Healthcare Infection Control Practices Advisory Committee (HICPAC) guidelines and to investigate serum levels of vancomycin.
    METHODOLOGY: The study was performed retrospectively. Medical records of patients treated with vancomycin for the past year were identified and selected.
    RESULTS: Overall, 118 patients were treated with vancomycin. Appropriate use of vancomycin was significantly higher than inappropriate use (p = 0.001). Approximately 85% (n = 100) of patients were given vancomycin for treatment, whereas the rest were given it for prophylaxis. Appropriate use of vancomycin was observed in 67% (n = 79) of patients. However, there was still a high rate of inappropriate vancomycin use for prophylaxis and treatment (n = 39, 33.1%). The most common reason for inappropriate use was non-neutropenic and non-line related sepsis (n = 36, 30.8%). Therapeutic drug monitoring of vancomycin was performed in 79 patients (67%). Most patients (n = 53, 67%) demonstrated sub-therapeutic levels during the first measurement. There was no significant difference between trough levels achieved with a higher (> 15 mg/kg) versus a lower dose (< 15 mg/kg).
    CONCLUSIONS: This study demonstrates that there was still a high level of inappropriate vancomycin use, which could potentially contribute to vancomycin resistance.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  11. Das B, Sarkar C, Schachter J
    Pak J Pharm Sci, 2013 Sep;26(5):1045-55.
    PMID: 24035967
    Natural glycopeptide antibiotics like vancomycin and teicoplanin have played a significant role in countering the threat posed by Gram-positive bacterial infections. The emergence of resistance to glycopeptides among enterococci and staphylococci has prompted the search for second-generation drugs of this class and semi-synthetic derivatives are currently under clinical trials. Antimicrobial resistance among Gram-positive organisms has been increasing steadily during the past several decades and the current development of antibiotics falls short of meeting the needs. Oritavancin (LY-333328 diphosphate), a promising novel second-generation semisynthetic lipoglycopeptide, has a mechanism of action similar to that of other glycopeptides. It has concentration-dependent activity against a variety of Gram-positive organisms specially methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate resistant Staphylococcus aureus (VISA), Streptococcus pneumoniae and vancomycin-resistant enterococcus. It is rapidly bactericidal against many species and in particular for enterococci where vancomycin and teicoplanin are only bacteriostatic even against susceptible strains. The pharmacokinetic profile of oritavancin has not been fully described; however, oritavancin has a long half-life of about 195.4 hours and is slowly eliminated by renal means. Oritavancin is not metabolized by the liver in animals. Oritavancin will most probably be prescribed as a once-daily dose and it demonstrates concentration-dependent bactericidal activity. Oritavancin has demonstrated preliminary safety and efficacy in Phase I and II clinical trials. In a Phase III clinical trial, oritavancin has achieved the primary efficacy end point in the treatment of complicated Gram-positive skin and skin-structure infections. To date, adverse events have been mild and limited; the most common being administration site complaints, headache, rhinitis, dry skin, pain, increases in liver transaminases and accumulation of free cholesterol and phospholipids in phagocytic (macrophages) and nonphagocytic (fibroblast) cells. Oritavancin appears to be a promising antimicrobial alternative to vancomycin (with additional activity against Staphylococcus and Enterococcus resistant to vancomycin) for the treatment of complicated Gram-positive skin and skin-structure infections. Additional clinical data are required to fully explore its use.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  12. Musa SH, Basri M, Masoumi HR, Karjiban RA, Malek EA, Basri H, et al.
    Colloids Surf B Biointerfaces, 2013 Dec 1;112:113-9.
    PMID: 23974000 DOI: 10.1016/j.colsurfb.2013.07.043
    Palm kernel oil esters nanoemulsion-loaded with chloramphenicol was optimized using response surface methodology (RSM), a multivariate statistical technique. Effect of independent variables (oil amount, lecithin amount and glycerol amount) toward response variables (particle size, polydispersity index, zeta potential and osmolality) were studied using central composite design (CCD). RSM analysis showed that the experimental data could be fitted into a second-order polynomial model. Chloramphenicol-loaded nanoemulsion was formulated by using high pressure homogenizer. The optimized chloramphenicol-loaded nanoemulsion response values for particle size, PDI, zeta potential and osmolality were 95.33nm, 0.238, -36.91mV, and 200mOsm/kg, respectively. The actual values of the formulated nanoemulsion were in good agreement with the predicted values obtained from RSM. The results showed that the optimized compositions have the potential to be used as a parenteral emulsion to cross blood-brain barrier (BBB) for meningitis treatment.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  13. Neela V, Rankouhi SZ, van Belkum A, Goering RV, Awang R
    Int J Infect Dis, 2012 Aug;16(8):e603-7.
    PMID: 22698885 DOI: 10.1016/j.ijid.2012.04.004
    Stenotrophomonas maltophilia is a recently identified nosocomial pathogen in Malaysia. Despite limited pathogenicity, its rate of isolation has increased in recent years. The aim of this study was to investigate the antibiotic susceptibility patterns, antibiotic resistance determinants, and the epidemiology of S. maltophilia at the largest tertiary care hospital in Malaysia.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics*
  14. Aldahoun MA, Jaafar MS, Al-Akhras MH, Bououdina M
    Artif Cells Nanomed Biotechnol, 2017 Jun;45(4):843-853.
    PMID: 27137748 DOI: 10.1080/21691401.2016.1178137
    Curcumin is more soluble in ethanol, dimethylsulfoxide, methanol and acetone than in water. In this study, nanocurcumin combined with 8 mT AC static magnetic field was used to enhance cellular uptake, bioavailability, and ultimate efficiency of curcumin against prostate cancer cell line (PC3), four bacteria strains (two Gram positive: Micrococcus luteus ATCC 9341, Staphylococcus aureus ATCC 29213 and two Gram negative: Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853), mammalian cell line (HEK) and human erythrocytes (RBC). The efficiency (E%) between IC50 of nanocurcumin combined with magnetic field (NANOCUR-MF) and control against PC3 was 35.93%, which is three times higher compared to curcumin combined with magnetic field (CUR-MF); i.e., 10.77%. However, their E% against HEK was not significant; 1.4% for NANOCUR-MF and 1.95% for CUR-MF. Moreover, depending in minimum bacterial concentration (MBC), the use of MF leads to a reduction of MBCs for all tested bacteria compared with control. The obtained results established the applicability of (MF) in enhancing cellular uptake for PC3 and tested bacteria strains by increasing the penetration of drug (nanocurcumin and parent curcumin) into cell with fixing mild cytotoxic profile for HEK and RBC.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  15. Lo YL, van Hasselt JG, Heng SC, Lim CT, Lee TC, Charles BG
    Antimicrob Agents Chemother, 2010 Jun;54(6):2626-32.
    PMID: 20385872 DOI: 10.1128/AAC.01370-09
    The present study determined the pharmacokinetic profile of vancomycin in premature Malaysian infants. A one-compartment infusion model with first-order elimination was fitted to serum vancomycin concentration data (n = 835 points) obtained retrospectively from the drug monitoring records of 116 premature newborn infants. Vancomycin concentrations were estimated by a fluorescence polarization immunoassay. Population and individual estimates of clearance and distribution volume and the factors which affected the variability observed for the values of these parameters were obtained using a population pharmacokinetic modeling approach. The predictive performance of the population model was evaluated by visual inspections of diagnostic plots and nonparametric bootstrapping with replacement. Dosing guidelines targeting a value of > or =400 for the area under the concentration-time curve over 24 h in the steady state divided by the MIC (AUC(24)/MIC ratio) were explored using Monte Carlo simulation. Body size (weight), postmenstrual age, and small-for-gestational-age status are important factors explaining the between-subject variability of vancomycin pharmacokinetic parameter values for premature neonates. The typical population parameter estimates of clearance and distribution volume for a 1-kg premature appropriate-for-gestational-age neonate with a postmenstrual age of 30 weeks were 0.0426 liters/h and 0.523 liters, respectively. There was a 20% reduction in clearance for small-for-gestational-age infants compared to the level for the appropriate-for-gestational-age control. Dosage regimens based on a priori target response values were formulated. In conclusion, the pharmacokinetic parameter values for vancomycin in premature Malaysian neonates were estimated. Improved dosage regimens based on a priori target response values were formulated by incorporating body size, postmenstrual age, and small-for-gestational-age status, using Monte Carlo simulations with the model-estimated pharmacokinetic parameter values.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics*
  16. Sulaiman H, Abdul-Aziz MH, Roberts JA
    Semin Respir Crit Care Med, 2017 06;38(3):271-286.
    PMID: 28578552 DOI: 10.1055/s-0037-1602716
    Hospital-acquired pneumonia and ventilator-associated pneumonia continue to cause significant morbidity and mortality. With increasing rates of antimicrobial resistance, the importance of optimizing antibiotic treatment is key to maximize treatment outcomes. This is especially important in critically ill patients in intensive care units, in whom the infection is usually caused by less susceptible organisms. In addition, the marked physiological changes that can occur in these patients can cause serious changes in antibiotic pharmacokinetics which in turn alter the attainment of therapeutic drug exposures. This article reviews the various aspects of the pharmacokinetic changes that can occur in the critically ill patients, the barriers to achieving therapeutic drug exposures in pneumonia for systemically delivered antibiotics, the optimization for commonly used antibiotics in hospital- and ventilator-associated pneumonia, the agents that should be avoided in the treatment regimen, as well as the use of adjunctive therapy in the form of nebulized antibiotics.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  17. Isaac IO, Al-Rashida M, Rahman SU, Alharthy RD, Asari A, Hameed A, et al.
    Bioorg Chem, 2019 02;82:6-16.
    PMID: 30267972 DOI: 10.1016/j.bioorg.2018.09.032
    Urease is a bacterial enzyme that is responsible for virulence of various pathogenic bacteria such as Staphylococcus aureus, Proteus mirabilis, Klebsiella pneumoniae, Ureaplasma urealyticum, Helicobacter pylori and Mycobacterium tuberculosis. Increased urease activity aids in survival and colonization of pathogenic bacteria causing several disorders especially gastric ulceration. Hence, urease inhibitors are used for treatment of such diseases. In search of new molecules with better urease inhibitory activity, herein we report a series of acridine derived (thio)semicarbazones (4a-4e, 6a-6l) that were found to be active against urease enzyme. Molecular docking studies were carried out to better comprehend the preferential mode of binding of these compounds against urease enzyme. Docking against urease from pathogenic bacterium S. pasteurii was also carried out with favorable results. In silico ADME evaluation was done to determine drug likeness of synthesized compounds.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  18. Liu R, Tang AM, Tan YL, Limenta LM, Lee EJ
    Eur J Clin Pharmacol, 2009 Jan;65(1):65-70.
    PMID: 18766334 DOI: 10.1007/s00228-008-0488-4
    OBJECTIVES: The aims of this study were to characterize the population frequency of PEPT2 (SLC15A2) polymorphic variants in three Asian ethnic populations, namely Chinese, Malay and Asian Indian, and to investigate the associations of ethnicity (Chinese vs. Asian Indian), PEPT2 haplotype and cephalexin pharmacokinetics in healthy Asian subjects.

    METHODS: PEPT2 polymorphisms were screened from a cohort of 96 Chinese, 96 Malay and 96 Asian Indian subjects. Cephalexin (1000 mg, orally) pharmacokinetics was characterized in an additional 15 Chinese and 15 Asian Indian healthy subjects. These 30 subjects were subsequently genotyped for their PEPT2 polymorphisms.

    RESULTS: In total, ten common single nucleotide polymorphisms (SNPs) were detected in the three populations, forming two PEPT2 haplotypes. There were significant ethnic differences in PEPT2 haplotype distribution: the frequencies of the *1 and *2 alleles were 0.307 and 0.693 in the Chinese population, 0.495 and 0.505 in the Malay population and 0.729 and 0.271 in Asian Indian population, respectively. The C (max) of cephalexin was significantly lower in the Chinese (29.80 +/- 4.09 microg ml(-1)) population than in the Asian Indian one (33.29 +/- 4.97 microg ml(-1); P = 0.045). This difference could be explained by the higher average body weight of the Chinese population. There was no other significant difference in cephalexin pharmacokinetics between either ethnic or PEPT2 genotype groups.

    CONCLUSION: PEPT2 polymorphism distributions differ significantly between Chinese, Malay and Asian Indian populations. However, cephalexin pharmacokinetics is not meaningfully different between Chinese and Asian Indians. The association between the PEPT2 haplotype and cephalexin pharmacokinetics could not be confirmed, and future studies under better controlled conditions are needed.

    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics*
  19. Makmor-Bakry M, Ahmat A, Shamsuddin A, Lau CL, Ramli R
    Anaesthesiol Intensive Ther, 2019;51(3):218-223.
    PMID: 31434472 DOI: 10.5114/ait.2019.87362
    BACKGROUND: Failure of antibiotic treatment increases mortality of critically ill patients. This study investigated the association between the treatment resolution of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia and vancomycin pharmacokinetic variables.

    METHODS: A total of 28 critically ill patients were included in this study. All data were collected from medical, microbiology and pharmacokinetic records. The clinical response was evaluated on the basis of clinical and microbiological parameters. The 24-h area under the curve (AUC0-24) was estimated from a single trough level using established equations.

    RESULTS: Out of the 28 patients, 46% were classified as responders to vancomycin treatment. The trough vancomycin concentration did not differ between the responders and non-responders (15.02 ± 6.16 and 14.83 ± 4.80 μg mL-1; P = 0.929). High vancomycin minimum inhibitory concentration (MIC) was observed among the non-responders (P = 0.007). The ratio between vancomycin trough concentration and vancomycin MIC was significantly lower in the non-responder group (8.76 ± 3.43 vs. 12.29 ± 4.85 μg mL-1; P = 0.034). The mean ratio of estimated AUC0-24 and vancomycin MIC was 313.78 ± 117.17 μg h mL-1 in the non-responder group and 464.44 ± 139.06 μg h mL-1 in the responder group (P = 0.004). AUC0-24/MIC of ≥ 400 μg h mL-1 was documented for 77% of the responders and 27% of the non-responders (c2 = 7.03; P = 0.008).

    CONCLUSIONS: Ratio of trough concentration/MIC and AUC0-24/MIC of vancomycin are better predictors for MRSA treatment outcomes than trough vancomycin concentration or AUC0-24 alone. The single trough-based estimated AUC may be sufficient for the monitoring of treatment response with vancomycin.

    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
  20. Hussein-Al-Ali SH, El Zowalaty ME, Hussein MZ, Ismail M, Webster TJ
    Int J Nanomedicine, 2014;9:549-57.
    PMID: 24549109 DOI: 10.2147/IJN.S53079
    This study describes the preparation, characterization, and controlled release of a streptomycin-chitosan-magnetic nanoparticle-based antibiotic in an effort to improve the treatment of bacterial infections. Specifically, chitosan-magnetic nanoparticles were synthesized by an incorporation method and were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and vibrating sample magnetometry. Streptomycin was incorporated into the nanoparticles to form a streptomycin-coated chitosan-magnetic nanoparticle (Strep-CS-MNP) nanocomposite. The release profiles showed an initially fast release, which became slower as time progressed. The percentage of drug released after 350 minutes was around 100%, and the best fit mathematical model for drug release was the pseudo-second order model. The Strep-CS-MNP nanocomposite showed enhanced antibacterial activity against methicillin-resistant Staphylococcus aureus. This study forms a significant basis for further investigation of the Strep-CS-MNP nanocomposite in the treatment of various bacterial infections.
    Matched MeSH terms: Anti-Bacterial Agents/pharmacokinetics
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