Maximum Drug Concentration Research Articles

Clinical Pharmacokinetics and Drug‐Drug Interaction Potential for Coadministered SCY‐078, an Oral Fungicidal Glucan Synthase Inhibitor, and Tacrolimus

SCY-078 is an orally bioavailable triterpenoid glucan synthase inhibitor in clinical development as an intravenous and oral treatment of fungal infections caused by Candida and Aspergillus species. This was a sequential, single-center, open-label phase 1 study to assess the drug-drug interaction potential between SCY-078 and tacrolimus during concomitant administration in healthy subjects. In cohort 1, period 1, subjects received a single oral dose of tacrolimus 2mg in the fasted state. In period 2 after a ≥15 day washout, subjects received a single loading dose of SCY-078 1250mg on day 1 followed by maintenance doses of SCY-780 750mg on days 2 through 8. On day 3 of period 2, subjects also received a single dose of tacrolimus 2mg concurrent with SCY-078. In cohort 2, subjects received a loading dose of SCY-078 1250mg on day 1 followed by maintenance doses of SCY-780 750mg on days 2 and 3. Pharmacokinetic (PK) parameters were compared to assess both the impact of steady-state SCY-078 on tacrolimus and the impact of tacrolimus on the PK of steady-state SCY-078. The concurrent coadministration of tacrolimus and SCY-078 had no effect on the maximum blood levels of tacrolimus, as evidenced by no change in maximum concentration of drug in blood plasma and a 1.4-fold increase in total area under the plasma drug concentration-time curve. The concurrent coadministration of tacrolimus and SCY-078 resulted in a weaker interaction than typically observed with the azole class of antifungals. The current data indicate that an initial dose adjustment for tacrolimus may not be warranted when combined with SCY-078, as the modest increase in exposure is less than the therapeutic window, although tacrolimus monitoring, as with addition of any new medication, is recommended. These results support the coadministration of SCY-078 and tacrolimus.

Novel Extended-Release Multiple-Unit System of Imidafenacin Prepared by Fluid-Bed Coating Technique.

The objective of this study was to formulate once-a-day extended-release (ER) pellet system of imidafenacin (IDN), a recently approved urinary antispasmodic agent with twice-a-day dosing regimen. The sugar sphere pellets were firstly layered with IDN and hypromellose and then coated with Eudragit RS (copolymers of acrylic and methacrylic acid esters), employed as a release modifier, using a fluid-bed coater. Solid-state characterizations using solid-state X-ray diffraction and differential scanning calorimeter indicated that the antispasmodic agent was homogeneously layered onto the pellets in an amorphous state. Drug release from multiple-unit ER system was effectively retarded in proportion to the amount of Eudragit RS in the outer layer, with a high correlation value above 0.86. In a pharmacokinetic evaluation in beagle dogs, the plasma concentration profile of IDN was markedly protracted by ER pellets, exhibiting delayed the time needed to reach the maximum drug concentration and the elimination half-life in plasma, compared to the commercial immediate release form (Uritos® tablet, Kyorin Pharmaceutical Co., Ltd., Japan). Therefore, the novel ER pellets can be a promising tool for oral IDN therapy, providing a once-a-day dosing regimen, and thus, improving patient compliance.

Integrating data from the Investigational Medicinal Product Dossier/investigator's brochure. A new tool for translational integration of preclinical effects.

Integrating data from the Investigational Medicinal Product Dossier/investigator's brochure. A new tool for translational integration of preclinical effects.

Pharmacokinetic and Pharmacodynamic Correlations From 2 Studies Evaluating Abuse Potential of Hydrocodone Extended-Release Tablets.

Pharmacokinetic (PK)/pharmacodynamic (PD) correlations were explored in 2 human abuse potential studies of orally and intranasally administered hydrocodone extended-release (ER) 45mg in healthy, nondependent opioid users. In a crossover study design, subjects received intact hydrocodone ER, finely milled hydrocodone ER, and hydrocodone powder in solution in the oral study and finely milled hydrocodone ER, hydrocodone powder, and finely milled Zohydro® ER in the intranasal study. Spearman ρ2 and Pearson r2 values were calculated for PD (maximum effect [Emax ] for "at the moment" Drug Liking, Overall Drug Liking, and Take Drug Again visual analog scales [VAS]) vs PK (partial area under the concentration-time curve [AUC], maximum drug concentration [Cmax ], time to Cmax [Tmax ], and abuse quotient [PK AQ; Cmax /Tmax ]) for all treatments. In the oral study, correlations were strongest between Emax of "at the moment" Drug Liking and PK parameters (Cmax [ρ2 =0.4446], PK AQ [ρ2 =0.5179], Tmax [ρ2 =0.5093], and early systemic exposure [ρ2 =0.4782]). For Overall Drug Liking and Take Drug Again VAS, ρ2 values for correlations with PK parameters ranged from 0.2620 to 0.3637. In the intranasal study, no clear correlations between PK and PD parameters were apparent.

Efficacy of Apramycin against Multidrug-Resistant Acinetobacter baumannii in the Murine Neutropenic Thigh Model.

Apramycin, an aminocyclitol aminoglycoside, was rapidly bactericidal against Acinetobacter baumannii In a neutropenic murine thigh infection model, treatment-associated A. baumannii CFU reductions of >4 log10 per thigh were observed for all exposures for which area under the curve (AUC)/MIC ratio was >50 and maximum concentration of drug in serum (Cmax)/MIC was ≈10 or higher. Based on these findings, we suggest that apramycin deserves further preclinical exploration as a repurposed therapeutic for multidrug-resistant Gram-negative pathogens, including A. baumannii.

Evaluation of Pazopanib Phase Behavior Following pH-Induced Supersaturation.

Salts of weakly basic active pharmaceutical ingredients are widely used to improve aqueous solubility and/or dissolution rate. However, these compounds are prone to precipitation due to the lower solubility of the un-ionized species at the higher pH in the intestinal region, and this can result in poor and/or variable absorption. The goal of this study was to investigate the degree of supersaturation achieved following dissolution of different amounts of pazopanib hydrochloride at low pH, followed by rapid pH increase. Using pH solubility profiles, phase boundaries were defined for crystalline and amorphous free base forms. The resultant phase diagram was used to rationalize the observed supersaturation and phase behavior of pazopanib following pH adjustment. In the presence of a crystallization inhibitor, hydroxypropylmethyl cellulose (HPMC), the degree of supersaturation was found to be very high, approximately 600-fold, at pH 6.5. At a dose equivalent to the clinical dose, the maximum free drug concentration observed at pH 6.5 was dictated by the amorphous solubility. Solutions that exceeded the amorphous solubility upon pH increase were found to undergo glass-liquid phase separations (GLPS) with the formation of amorphous colloidal drug-rich particles. Microscopic observations confirmed that HPMC delayed the appearance of pazopanib free base crystals. The phase behavior upon pH change is thus well predicted by the phase diagram, after taking into consideration the initial dose, the extent of supersaturation generated upon pH change, and the presence or absence of a crystallization inhibitor.

Pharmacokinetics of multiple doses of transdermal flunixin meglumine in adult Holstein dairy cows.

A transdermal formulation of the nonsteroidal anti-inflammatory drug, flunixin meglumine, has been approved in the United States and Canada for single-dose administration. Transdermal flunixin meglumine was administered to 10 adult Holstein cows in their second or third lactation at the label dose of 3.33mg/kg every 24hr for three total treatments. Plasma flunixin concentrations were determined using high-pressure liquid chromatography with mass spectroscopy (HPLC-MS). Pharmacokinetic analysis was completed on each individual animal with noncompartmental methods using computer software. The time to maximum drug concentration (Tmax) was 2.81hr, and the maximum drug concentration was 1.08μg/ml. The mean terminal half-life (T½) was determined to be 5.20hr. Clearance per fraction absorbed (Cl/F) was calculated to be 0.294L/hrkg-1 , and volume of distribution of fraction (Vz/F) absorbed was 2.20L/kg. The mean accumulation factor was 1.10 after three doses. This indicates changes in dosing may not be required when giving multiple doses of flunixin transdermal. Further work is required to investigate the clinical efficacy of transdermal flunixin after multiple daily doses.

Peripheral α2-adrenoceptor antagonism affects the absorption of intramuscularly coadministered drugs

ObjectiveWe determined the possible effects of a peripherally acting α2-adrenoceptor antagonist, MK-467, on the absorption of intramuscularly (IM) coadministered medetomidine, butorphanol and midazolam. Study designRandomized, experimental, blinded crossover study. AnimalsSix healthy Beagle dogs. MethodsTwo IM treatments were administered: 1) medetomidine hydrochloride (20 μg kg–1) + butorphanol (100 μg kg–1) + midazolam (200 μg kg–1; MBM) and 2) MBM + MK-467 hydrochloride (500 μg kg–1; MBM–MK), mixed in a syringe. Heart rate was recorded at regular intervals. Sedation was assessed with visual analog scales (0–100 mm). Drug concentrations in plasma were analyzed with liquid chromatography–tandem mass spectrometry, with chiral separation of dex- and levomedetomidine. Maximum drug concentrations in plasma (Cmax) and time to Cmax (Tmax) were determined. Paired t-tests, with Bonferroni correction when appropriate, were used for comparisons between the treatments. ResultsData from five dogs were analyzed. Heart rate was significantly higher from 20 to 90 minutes after MBM–MK. The Tmax values for midazolam and levomedetomidine (mean ± standard deviation) were approximately halved with coadministration of MK-467, from 23 ± 9 to 11 ± 6 minutes (p = 0.049) for midazolam and from 32 ± 15 to 18 ± 6 minutes for levomedetomidine (p = 0.036), respectively. Conclusions and clinical relevanceMK-467 accelerated the absorption of IM coadministered drugs. This is clinically relevant as it may hasten the onset of peak sedative effects.

A Pharmacokinetic Study of an Ibuprofen Topical Patch in Healthy Male and Female Adult Volunteers.

The pharmacokinetics of a novel locally applied ibuprofen topical patch was evaluated. Healthy subjects (n=28) were administered a 200-mg ibuprofen patch every 24hours for 5 days, and steady-state pharmacokinetics was determined. The amount of ibuprofen remaining in the patch following each patch removal was also assessed. The maximum steady-state drug concentration and area under the concentration curve from time 0 on day5 (t=0) to the 24-hours sample on day 6 were 514ng/mL (95% CI 439 to 603ng/mL) and 9.78kg·h/mL (95% CI 8.43 to 11.4kg·h/mL), respectively. Maximum ibuprofen concentration on day 5 occurred at 20 hours post-patch application. No evidence of drug accumulation was observed, and steady state was achieved between days 2 and 5. Ibuprofen levels attenuated rapidly to baseline within 24hours after treatment discontinuation. The amount of ibuprofen remaining in the patch was high (≥80%). Treatment-emergent adverse events were generally mild, with the most prevalent being headache (n=6; 21.4%). Only 4 TEAEs were considered related to the ibuprofen patch: paresthesia (n=1), headache (n=2), and pruritic rash (n=1). The study found that the systematic absorption of ibuprofen from a 200-mg patch was low and that the levels of ibuprofen leaving the patch over a 24-hour period are consistent with levels required for therapeutic relief as shown in other studies.

A Unified Mathematical Model for Nano-Liposomal Drug Delivery to Solid Tumors.

Nanoparticles, such as liposomes, allow more targeted drug delivery for improved efficacy and/or reduced toxicity in both passive (e.g., Doxil) or active [e.g., thermo-sensitive liposomes (TSL)] release forms compared with unencapsulated drugs (i.e., conventional chemotherapy). Optimization and evaluation of these different drug delivery systems are experimentally challenging because of varying tissue parameters as well as limited avaiability of experimental data. Here, we present a novel unified mathematical model that can simulate various liposomal drug delivery systems and unencapsulated drugs with a single set of equations. We use this model to evaluate the chemotherapy performance of free Doxorubicin (as drug), as well as various liposomal drug delivery systems: 1) passive liposomes (Doxil) and 2) active-triggered TSL with either intravascular (TSLi) or extravascular (TSLe)-triggered release. Furthermore, we implemented a more accurate expression to consider incomplete liposomal drug release. The proposed model matches experimental in vivo results in terms of maximum drug concentration in tumor. The simulations predict better overall performance for all liposomal delivery systems than free Dox. TSLe is shown to be more efficient for less permeable and perfused tumors than other systems. The optimal release rate is lower for TSLe and Doxil than TSLi. The performance of free DOX changes a little for varying tumor characteristics such as perfusion and permeability.

Pharmacokinetics of Conventional and Long-Acting Oxytetracycline Preparations in Kilis Goat.

The pharmacokinetics of conventional and long-acting (LA) oxytetracycline (OTC), widely used broad-spectrum antibacterial drugs in veterinary medicine, were evaluated in Kilis goats at single dosage of 20 mg/kg body weight (bw). A total of 21 goats were divided into three groups: intravenous (Group I) and intramuscular (IM) (Group II) administration of the conventional formulation and IM administration of the LA formulation (Group III). Blood samples were taken at 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, 60, 72, and 96 h; and OTC analysis was performed by HPLC. For Group III and Group II, time to reach maximal plasma drug concentration (Tmax) was 0.6 ± 0.28 and 0.46 ± 0.09 h and maximal plasma drug concentrations (Cmax) were 8.72 ± 2.47 μg/ml and 13.57 ± 5.83 μg/ml, respectively. In Group I, C0 concentration was found to be 63.51 ± 11.59 μg/ml. The elimination times (T1/2) were 10.84 ± 3.20, 27.96 ± 11.66, and 10.47 ± 1.30 h; and AUC were 115 ± 29.12, 96.44 ± 9.49, and 80.86 ± 12.76 μg/ml/h for Group I; Group II, and Group III, respectively. Bioavailability by IM administration were 69.71% for the conventional OTC and 83.15% for the LA OTC.

Understanding the generation and maintenance of supersaturation during the dissolution of amorphous solid dispersions using modulated DSC and 1H NMR

In this study, the dissolution behaviour of dipyridamole (DPM) and cinnarizine (CNZ) spray-dried amorphous solid dispersions (ASDs) using polyvinyl pyrrolidone (PVP) and polyacrylic acid (PAA) as a carrier matrix were evaluated and compared. The drug concentrations achieved from the dissolution of PVP and PAA solid dispersions were significantly greater than the equilibrium solubility of crystalline DPM and CNZ in phosphate buffer pH 6.8 (PBS 6.8). The maximum drug concentration achieved by dissolution of PVP and PAA solid dispersions did not exceed the theoretically calculated apparent solubility of amorphous DPM and CNZ. However, the degree of supersaturation of DPM and CNZ increased considerably as the polymer weight fraction within the solid dispersion increased. In addition, the supersaturation profile of DPM and CNZ were studied in the presence and absence of the polymers. PAA was found to maintain a higher level of supersaturation compared to PVP. The enhanced drug solution concentration following dissolution of ASDs can be attributed to the reduced crystal growth rates of DPM and CNZ at an equivalent supersaturation. We have also shown that, for drugs having high crystallization tendency and weak drug-polymer interaction, the feasible way to increase dissolution might be increase the polymer weight fraction in the ASD. Solution 1H NMR spectra were used to understand dissolution mechanism and to identify drug-polymer interaction. The change in electron densities of proton attached to different groups in DPM and CNZ suggested drug-polymer interaction in solution. The relative intensities of peak shift and nature of interaction between drug and polymer in different systems are different. These different effects suggest that DPM and CNZ interacts in a different way with PVP and PAA in solution which goes some way towards explaining the different polymeric effect, particularly in terms of inhibition of drug recrystallization and dissolution of DPM and CNZ ASDs. These results established that the different drug/polymer interactions in the solid state and in solution give rise to the variation in dissolution profile observed for different systems.

Amplification of Antimicrobial Resistance in Gut Flora of Patients Treated with Ceftriaxone.

Although antibacterial therapy has an impact on human intestinal flora and the emergence of resistant bacteria, its role in the amplification of antimicrobial resistance and the quantitative exposure-effect relationship is not clear. An observational prospective study was conducted to determine whether and how ceftriaxone exposure is related to amplification of resistance in non-intensive care unit (non-ICU) patients. Serial stool samples from 122 extended-spectrum β-lactamase-positive (ESBL+) hospitalized patients were analyzed by quantitative real-time PCR to quantify the resistant gene blaCTX-M Drug exposure was calculated for each patient by using a population pharmacokinetic model. Multi- and univariate regression and classification regression tree (CART) analyses were used to explore relationships between measures of exposure and amplification of blaCTX-M genes. Amplification of blaCTX-M was observed in 0% (0/11) of patients with no treatment and 33% (20/61) of patients treated with ceftriaxone. Stepwise regression analysis showed a significant association between amplification of blaCTX-M and the plasma area under the concentration-time curve from 0 to 24 h for the unbound fraction of the drug (fAUC0-24), the maximum concentration of drug in serum for the unbound fraction of the drug (fCmax), and the duration of ceftriaxone therapy. Using CART analysis, amplification of blaCTX-M was observed in 11/16 (69%) patients treated for >14 days and in 9/40 (23%) patients treated for ≤14 days (P = 0.0019). In the latter group, amplification was observed in 5/7 (71%) patients with an fAUC0-24 of ≥222 mg · h/liter and in 4/33 (12%) patients with lower drug exposures (P = 0.0033). A similar association was found for an fCmax of ≥30 mg/liter (63% versus 13%, P = 0.0079). A significant association was found between the amplification of blaCTX-M resistance genes and exposure to ceftriaxone. Both duration of treatment and degree of ceftriaxone exposure have a significant impact on the amplification of resistance genes. (The project described in this paper has been registered at ClinicalTrials.gov under identifier NCT01208519.).

Pharmacokinetics of Beclomethasone Dipropionate Delivered by Breath-Actuated Inhaler and Metered-Dose Inhaler in Healthy Subjects.

Breath-actuated inhalers (BAIs) eliminate the need for hand-breath coordination required of pressurized metered-dose inhalers (MDIs). This pharmacokinetic study compared systemic exposure following beclomethasone dipropionate delivery through BAI versus MDI. This open-label, three-period crossover, single-dose study randomized healthy subjects aged 18-45 years (N = 72) to 1 of 6 treatment sequences containing beclomethasone dipropionate BAI 160 mcg (40 mcg/inhalation, 4 inhalations), beclomethasone dipropionate BAI 320 mcg (80 mcg/inhalation, 4 inhalations), and beclomethasone dipropionate MDI 320 mcg (80 mcg/inhalation, 4 inhalations). Blood samples were collected predose through 24 hours postdose for determination of plasma concentrations of beclomethasone-17-monopropionate (17-BMP), the active metabolite of beclomethasone dipropionate. The primary pharmacokinetic parameters were area under the plasma drug concentration-time curve (AUC) from time 0 (predose) until the last measurable drug concentration (AUC0-t) and maximum plasma drug concentration (Cmax) for 17-BMP. Safety was assessed by adverse events, vital signs, clinical laboratory tests, and physical examinations. Plasma concentrations of 17-BMP peaked at a median of 10 minutes after the last inhalation of all study treatments and remained measurable for at least 18 hours in most subjects. Mean elimination half-life was ∼4 hours. The AUC0-t and Cmax for 17-BMP were 11% and 14% higher, respectively, when beclomethasone dipropionate 320 mcg was administered through BAI versus MDI, but the 90% confidence intervals of the geometric least squares mean BAI:MDI ratio for each parameter were fully contained within the bioequivalence boundaries of 0.80-1.25. Plasma concentrations of 17-BMP following beclomethasone dipropionate 160 mcg BAI were approximately half those with 320 mcg through BAI or MDI. All treatments were safe and generally well tolerated. Systemic availability of 17-BMP following administration of beclomethasone dipropionate was bioequivalent between BAI and MDI at the 320-mcg dose, and approximately dose proportional at the 160- and 320-mcg doses using the BAI.

Use of Population Pharmacokinetics and Electronic Health Records to Assess Piperacillin-Tazobactam Safety in Infants.

Piperacillin, in combination with tazobactam, is frequently used in infants for treating nosocomial infections, although safety data in this population are limited. Electronic health record (EHR) data can be used to evaluate drug safety in infants, but measures of drug exposure are lacking. To relate simulated piperacillin exposure with adverse events (AEs) in infants using EHR data, we identified infants discharged from 333 neonatal intensive care units managed by the Pediatrix Medical Group between 1997 and 2012. Using a previously published population pharmacokinetic model in the target population, we simulated piperacillin steady state area under the concentration versus time curve from zero to τ (AUCss,0-τ) and steady state maximal drug concentration (Cmaxss). Next, we used multivariable logistic regression to evaluate the association between simulated AUCss,0-τ and Cmaxss with clinical AEs (seizure and rash) and laboratory AEs controlling for gestational age. The odds ratios (95% confidence intervals) comparing the third versus the first tertiles for AUCss,0-τ and Cmaxss were reported. We identified 746 infants with a median (interquartile range) gestational age of 30 weeks (26-33) and postnatal age of 11 days (6-25). The median (interquartile range) piperacillin dose was 225 mg/kg/d (176-300). No significant associations were found between simulated piperacillin exposure (AUCss,0-τ and Cmaxss) and clinical and laboratory AEs. We found no associations between predicted piperacillin exposures and the occurrence of AEs. This study confirms the feasibility of using population pharmacokinetics and EHR to relate drug exposure with safety.

Bubble-generating nano-lipid carriers for ultrasound/CT imaging-guided efficient tumor therapy

Ideal therapeutic effectiveness of chemotherapy is obtained only when tumor cells are exposed to a maximal drug concentration, which is often hindered by dose-limiting toxicity. We designed a bubble-generating liposomal delivery system by introducing ammonium bicarbonate and gold nanorods into folic acid-conjugated liposomes to allow both multimodal imaging and the local release of drug (doxorubicin) with hyperthermia. The key component, ammonium bicarbonate, allows a controlled, rapid release of doxorubicin to provide an effective drug concentration in the tumor microenvironment. An in vitro temperature-triggered drug release study showed that cumulative release improved more than two-fold. In addition, in vitro and in vivo studies indicated that local heat treatment or ultrasonic cavitation enhanced the therapeutic efficiency greatly. The delivery system could also serve as an excellent contrast agent to allow ultrasonic imaging and computerized tomography imaging simultaneously to further achieve the aim of accurate diagnostics. Results of this study showed that this versatile bubble-generating liposome is a promising system to provide optimal therapeutic effects that are guided by multimodal imaging.

Pharmacodynamic Optimization for Treatment of Invasive Candida auris Infection.

Candida auris is an emerging multidrug-resistant threat. The pharmacodynamics of three antifungal classes against nine C. auris strains was explored using a murine invasive candidiasis model. The total drug median pharmacodynamic (PD) target associated with net stasis was a fluconazole AUC/MIC (the area under the concentration-time curve over 24 h in the steady state divided by the MIC) of 26, an amphotericin B Cmax/MIC (maximum concentration of drug in serum divided by the MIC) of 0.9, and a micafungin AUC/MIC of 54. The micafungin PD targets for C. auris were ≥20-fold lower than those of other Candida species in this animal model. Clinically relevant micafungin exposures produced the most killing among the three classes.

Model averaging for robust assessment of QT prolongation by concentration-response analysis.

Assessing the QT prolongation potential of a drug is typically done based on pivotal safety studies called thorough QT studies. Model-based estimation of the drug-induced QT prolongation at the estimated mean maximum drug concentration could increase efficiency over the currently used intersection-union test. However, robustness against model misspecification needs to be guaranteed in pivotal settings. The objective of this work was to develop an efficient, fully prespecified model-based inference method for thorough QT studies, which controls the type I error and provides satisfactory test power. This is achieved by model averaging: The proposed estimator of the concentration-response relationship is a weighted average of a parametric (linear) and a nonparametric (monotonic I-splines) estimator, with weights based on mean integrated square error. The desired properties of the method were confirmed in an extensive simulation study, which demonstrated that the proposed method controlled the type I error adequately, and that its power was higher than the power of the nonparametric method alone. The method can be extended from thorough QT studies to the analysis of QT data from pooled phase I studies.

Effects on the QT Interval of a Gatifloxacin-Containing Regimen versus Standard Treatment of Pulmonary Tuberculosis.

ABSTRACTThe effects on ventricular repolarization—recorded on the electrocardiogram (ECG) as lengthening of the QT interval—of acute tuberculosis and those of standard and alternative antituberculosis regimens are underdocumented. A correction factor (QTc) is introduced to make the QT independent of the heart rate, translating into the slope of the regression line between QT and heart rate being close to zero. ECGs were performed predosing and 1 to 5 h postdosing (month 1, month 2, and end of treatment) around drugs' peak concentration time in tuberculosis patients treated with either the standard 6-month treatment (rifampin and isoniazid for 6 months and pyrazinamide and ethambutol for 2 months; “control”) or a test regimen with gatifloxacin, rifampin, and isoniazid given for 4 months (pyrazinamide for the first 2 months) as part of the OFLOTUB study, a randomized controlled trial conducted in five African countries. Drug levels were measured at steady state (month 1) in a subset of patients. We compared treatment effects on the QTc and modeled the effect of individual drugs' maximum concentrations of drug in serum (Cmax) on the Fridericia-corrected QT interval. A total of 1,686 patients were eligible for the correction factor analysis of QT at baseline (mean age, 30.7 years; 27% female). Median heart rate decreased from 96/min at baseline to 71/min at end of treatment, and body temperature decreased from 37.2 to 36.5°C. Pretreatment, the nonlinear model estimated the best correction factor at 0.4081 in between Bazett's (0.5) and Fridericia's (0.33) corrections. On treatment, Fridericia (QTcF) was the best correction factor. A total of 1,602 patients contributed to the analysis of QTcF by treatment arm. The peak QTcF value during follow-up was >480 ms for 21 patients (7 and 14 in the test and control arms, respectively) and >500 ms for 9 patients (5 and 4, respectively), corresponding to a risk difference of −0.9% (95% confidence interval [CI], −2.0% to 2.3%; P = 0.12) and 0.1% (95% CI, −0.6% to 0.9%; P = 0.75), respectively, between the test and control arms. One hundred six (6.6%) patients had a peak measurement change from baseline of >60 ms (adjusted between-arm difference, 0.8%; 95% CI, −1.4% to 3.1%; P = 0.47). No evidence was found of an association between Cmax of the antituberculosis drugs 1 month into treatment and the length of QTcF. Neither a standard 6-month nor a 4-month gatifloxacin-based regimen appears to carry a sizable risk of QT prolongation in patients with newly diagnosed pulmonary tuberculosis. This is to date the largest data set studying the effects of antituberculosis regimens on the QT, both for the standard regimen and for a fluoroquinolone-containing regimen. (This study has been registered at ClinicalTrials.gov under identifier NCT00216385.)

The effectiveness of endobronchial therapy in patients with chemo-resistant tuberculosis when specific process is localized in the lungs apical segments

Objective – to study the effectiveness of the additional methods of endobronchial pathology treatment in patients with chemo-resistant tuberculosis (CRTB) of lungs, that aimed to treat a specific process in bronchi when destructions are localized in the apical segments (S 1+2 ) of lungs. Materials and methods. In order to investigate effectiveness of the additional methods of endobronchial pathology treatment of bronchial mucosa 79 patients with CRTB of lungs were examined. They were divided into 3 groups: basic 1 group, which included 27 patients who were treated by using antimycobacterial drugs endobronchial introduction to S 1+2 with further implementation of intraorganic electrophoresis in S 1+2 zone in combination with systemic receiving of antimycobacterial drugs; the comparison basic 2 group 27 patients who were treated with systemic antimycobacterial therapy in combination with antituberculosis drugs inhalations; and the group included – 25 patients who received only systemic antimycobacterial therapy. Groups were compared by the severity of the process, age and gender. Tracheobronchial tree fiber-bronchoscopy in patients with CRTB of lungs was carried out on the basis of phthisiology and pulmonology department of ZSMU in communal institution Zaporizhzhia regional antituberculosis dispensary, by the author on their own. Character of bronchial mucosa was examined under anesthesia by fiber-bronchoscopes of company Olympus (Japan). Bronchial tree pathology was described according to N. V. Shesterynoy, A. N. Kaliuk (1975) classification. Results of the study were processed with modern methods of analysis on a personal computer with using the Statistical Package license software Statistica ® for Windows 6.0 (StatSoft Inc., № AXXR712 D833214FAN5). Results. The use of antimycobacterial drugs endobronchial introduction to S 1+2 with further implementation of intraorganic electrophoresis in S 1+2 zone contributed significantly increase the frequency of bacterial excretion completion in 1.6 times, the frequency of destructions healing – in 1.8 times with healing time reducing by 1.5 months. It allowed reduce incidences of S 1+2 segmental bronchi meta-tuberculosis stenosis in 4.1 times, which contributed to increase the effectiveness of treatment by 36.6 %. The using of antituberculosis drugs inhalations allowed significantly increase the frequency of bacterial excretion completion in 1.4 times and reduce incidences of S 1+2 segmental bronchi meta-tuberculosis stenosis in 2.4 times that contributed to increase the effectiveness of treatment by 28.9 %. Conclusions. When combined use of antimycobacterial drugs endobronchial introduction to S 1+2 with further implementation of intraorganic electrophoresis in S 1+2 zone in combination with systemic receiving of antimycobacterial drugs, it allows to direct the maximum drug concentration in the affected area, that increase the effectiveness of treatment by 36.6 %.