Cefepime distribution by microdialysis in peritoneal fluid of rats with or without experimental peritonitis.

The aim of this study was to investigate the penetration of cefepime into rat peritoneal fluid by microdialysis and to determine the relationship between unbound drug plasma and tissue concentration in healthy animals and in a sepsis model established through cecal ligation and puncture-induced peritonitis. Probe recovery was performed by dialysis and retrodialysis. Cefepime was administered at a dose of 110 mg/kg intravenously. Samples were collected for about 4 h, and concentrations were determined by liquid chromatography-electrospray ionization-QTOF MS. Tissue penetration was also determined. Probe recovery in vivo was 38.78% ± 3.31% and 38.83% ± 2.74% in the control and peritonitis groups, respectively. Cefepime was rapidly distributed in the peritoneal fluid in both groups. The peritoneal fluid/plasma cefepime ratio was 0.38 and 0.32 for the control and peritonitis groups, respectively. Cefepime concentrations were above the MIC of 4 mg/L for the main enterobacteria. The infection model that was used had no apparent effect on the pharmacokinetics of cefepime in rats. This was the first study to determine free cefepime concentrations in the peritoneal fluid of healthy rats and rats with experimental peritonitis.

Fast determination of free metronidazole in rat plasma and peritoneal fluid using HPLC-UV method.

Peritonitis refers to the inflammatory reaction of the peritoneum to aggression. In addition, it contributes significantly to sepsis. The presence of free concentrations of antimicrobials above the minimum inhibitory concentration at the site of infection is critical to therapeutic response. Metronidazole (MTZ) is an antimicrobial used to treat peritonitis because of its effectiveness against anaerobic microorganisms. This study investigates free MTZ concentrations in peritoneal microdialysate in Wistar rats. A C18 column (150 × 4.0 mm, 5 µm) was used for the analysis conducted at 40°C under isocratic conditions. The mobile phase consisted of acetonitrile and an aqueous solution of 50-mM monobasic phosphate buffer and 0.1% triethylamine, with pH 3.0 (10:90, v/v). MTZ calibration was linear in the range of 0.5-30.0 µg/ml. The intra- and inter-day precision was satisfactory with relative standard deviation ≤5.67%. The accuracy ranged from 90.64 to 103.77%, and the lower limit of quantification was 0.5 µg/ml. The developed method was successfully applied in a pilot pharmacokinetic study after MTZ administration (30 mg/kg, intravenously) in rats. The main advantage of the employed method is that it does not require sample processing and protein removal steps. This is the first study to be conducted using MTZ in rats.

Development and validation of an LC-ESI-QTOF-MS method to measure cefepime in the plasma and peritoneal fluid of rats using microdialysis: Application in a pilot pharmacokinetic study.

Cefepime (CEF) is a cephalosporin and can be administered in secondary peritonitis together with metronidazole to treat sepsis. This study aimed to develop and validate an LC-ESI-QTOF-MS method for the quantification of cefepime in the plasma and peritoneal microdialysate of healthy Wistar rats. Chromatographic separation was performed using a CLC-ODS C18 column (250 × 4.6 mm), a C18 pre-column (4 mm, 5 µm) and isocratic elution. Gallic acid was used as the internal standard. The mobile phase consisted of (A) ultrapure water (pH adjusted to 3.5) and (B) acetonitrile (80:20, v/v) at 0.8 ml/min. Quantification was performed using a mass spectrometer with electrospray ionization in positive mode to monitor ions with m/z 481.1322 (CEF) and m/z 171.0288 (IS). The method was validated for selectivity, precision, accuracy, linearity, stability, lower limit of quantification, carryover, recovery and matrix effect. Calibration was done in the ranges 1-40 and 1-100 µg/ml for the peritoneal microdialysate and plasma, respectively. Plasma extraction recovery ranged from 93.9 to 99.9%. The technique was validated and successfully applied in a pilot pharmacokinetic study for estimating the free concentration of CEF in the peritoneal microdialysate of rats for the first time.

Is clindamycin a potential treatment for prostatitis?

Cutibacterium acnes has been associated with chronic prostatitis, which can potentially favor the appearance of tumors in the prostate. Prostatitis is difficult to treat, and the drug needs to be able to penetrate the prostate. The aim was to investigate the pharmacokinetics of clindamycin in the interstitial fluid of rat prostate using microdialysis. Microdialysis probes were recovered in vitro and in vivo. Clindamycin was administered at 80 mg/kg iv bolus for plasma and tissue pharmacokinetic experiments. A microdialysis probe was implanted in the prostate gland for collections over an 8-hour period. The pharmacokinetic parameters were determined by both compartmental and non-compartmental approaches. Penetration was determined as the ratio between the area under the curve and the time of the clindamycin measurement in the prostate. The recovery of the in vivo probes was 38.11 ± 1.14%. The plasma profile was modeled by a two-compartment pharmacokinetic model. Clindamycin presented a prostate/plasma ratio of 1.02, with free concentrations above the minimum inhibitory concentration for Cutibacterium acnes isolates. This was the first study that determined clindamycin free concentrations in the prostatic fluid of rats. These findings suggest that clindamycin may be an effective alternative for the treatment of prostatitis caused by Cutibacterium acnes.

PK/PD modeling of daptomycin against MRSA and MRSE and Monte Carlo simulation for bacteremia treatment.

OBJECTIVES: The aim of this study was to investigate the effect of daptomycin against methicillin-resistant staphylococci (MRSA and MRSE) bacteremia using computer modeling. METHODS: A pharmacokinetic/pharmacodynamic (PK/PD) modeling strategy to explain the data from an in vitro dynamic model employing time-kill curves for MRSA and MRSE was proposed. Bacterial killing was followed over time by determining viable counts and the resulting time-kill data was analyzed. Monte Carlo simulations were performed using pharmacokinetic parameters and pharmacodynamic data to determine the probabilities of target attainment and cumulative fractions of response in terms of area under the concentration curve/minimum inhibition concentration (MIC) targets of daptomycin. Simulations were conducted to assess the reduction in the number of colony-forming units (CFU)/mL for 18 days of treatment with daptomycin at doses of 6, 8, and 10 mg/kg/24 h or 48 h with variations in creatinine clearance (CLCR): 15-29 mL/min/1.73 m2, 30-49 mL/min/1.73 m2, 50-100 mL/min/1.73 m2, as well as for defining the probability of reaching the target fAUC/MIC = 80 in the same dose and clearance range. A PK/PD model with saturation in the number of bacteria in vitro, growth delay, and bacterial death, as well as Hill's factor, was used to describe the data for both MRSA and MRSE. RESULTS: Monte Carlo simulations showed that for MRSA there was a reduction > 2 log CFU/mL with doses ≥ 6 mg/kg/day in 75th percentile of the simulated population after 18 days of treatment with daptomycin, whereas for MRSE this reduction was observed in 95th percentile of the population. CONCLUSIONS: The presented in vitro PK/PD model and associated modeling approach were able to characterize the time-kill kinetics of MRSA and MRSE. Our study based on PTAs suggests that doses ≥ 6 mg/kg/day of daptomycin should be used to treat bacteremia caused by MRSA and MRSE in patients with CLCR of 15-29 mL/min/1.73 m2. For patients with CLCR ≥ 50 mL/min/1.73 m2, it would be necessary to employ a dose of 10 mg/kg/day to treat complicated bacteremias.

Intravenous contrast use and acute kidney injury: a retrospective study of 1,238 inpatients undergoing computed tomography.

OBJECTIVE: To determine the incidence of nephropathy induced by intravenous contrast in hospitalized patients undergoing computed tomography (CT). MATERIALS AND METHODS: This was a retrospective cohort study involving 1,238 patients who underwent CT with or without intravenous administration of a contrast agent (iopromide). The primary outcome measure was acute kidney injury (AKI), as defined by the traditional criteria-an absolute or relative increase in serum creatinine (SCr) ≥ 0.5 mg/dL or ≥ 25% over baseline, respectively, at 2-3 days after contrast administration-and the newer, Kidney Disease: Improving Global Outcomes (KDIGO) criteria-an absolute or relative increase in SCr ≥ 0.3 mg/dL or ≥ 50% over baseline, respectively, at 2-7 days after contrast administration. RESULTS: The overall incidence of AKI was 11.52% when the KDIGO criteria were applied. Univariate logistic regression demonstrated a significant association between an absolute post-CT increase in SCr ≥ 0.5 mg/dL and AKI, although that association did not retain significance in the multivariate analysis. Multivariate logistic regression initially found an association between an absolute post-CT increase in SCr ≥ 0.3 mg/dL and advanced age, although that association was not maintained after correction. We found no association between AKI and the risk factors evaluated. CONCLUSION: We identified no criteria for contrast-induced nephropathy after CT; nor did we find AKI to be associated with the classical risk factors.

OBJETIVO: Determinar a incidência de nefropatia induzida por contraste intravenoso em pacientes hospitalizados submetidos a tomografia computadorizada (TC). MATERIAIS E MÉTODOS: Estudo de coorte retrospectivo que alocou 1.238 pacientes submetidos a TC sem ou com contraste (iopromida). O desfecho primário foi nefropatia induzida por contraste, definida pelo critério antigo - aumento absoluto ou relativo na creatinina sérica (SCr) ≥ 0,5 mg/dL ou ≥ 25%, respectivamente, durante 2-3 dias após a administração -, e o novo, Kidney Disease Improving Global Outcomes (KDIGO) - aumento absoluto ou relativo na SCr ≥ 0,3 mg/dL ou ≥ 50%, respectivamente, durante 2-7 dias após a administração. RESULTADOS: A incidência de lesão renal aguda foi de 11,52% aplicando os critérios KDIGO. A regressão logística univariada demonstrou significância relacionada à associação entre aumento absoluto da SCr ≥ 0,5 mg/dL após TC e lesão renal aguda. A regressão logística multivariada encontrou, inicialmente, associação entre aumento absoluto da SCr ≥ 0,3 mg/dL após TC e idade avançada, mas a associação não foi mantida após correção. Não foi encontrada associação entre lesão renal aguda e os fatores de risco avaliados. CONCLUSÃO: Não foram encontrados critérios para nefropatia induzida por contraste após TC ou associação de lesão renal aguda com fatores de risco clássicos.

Intravenous contrast use and acute kidney injury: a retrospective study of 1,238 inpatients undergoing computed tomography / Uso de contraste intravenoso e lesão renal aguda: estudo retrospectivo de 1.238 pacientes internados submetidos a tomografia computadorizada

Abstract Objective: To determine the incidence of nephropathy induced by intravenous contrast in hospitalized patients undergoing computed tomography (CT). Materials and Methods: This was a retrospective cohort study involving 1,238 patients who underwent CT with or without intravenous administration of a contrast agent (iopromide). The primary outcome measure was acute kidney injury (AKI), as defined by the traditional criteria-an absolute or relative increase in serum creatinine (SCr) ≥ 0.5 mg/dL or ≥ 25% over baseline, respectively, at 2-3 days after contrast administration-and the newer, Kidney Disease: Improving Global Outcomes (KDIGO) criteria-an absolute or relative increase in SCr ≥ 0.3 mg/dL or ≥ 50% over baseline, respectively, at 2-7 days after contrast administration. Results: The overall incidence of AKI was 11.52% when the KDIGO criteria were applied. Univariate logistic regression demonstrated a significant association between an absolute post-CT increase in SCr ≥ 0.5 mg/dL and AKI, although that association did not retain significance in the multivariate analysis. Multivariate logistic regression initially found an association between an absolute post-CT increase in SCr ≥ 0.3 mg/dL and advanced age, although that association was not maintained after correction. We found no association between AKI and the risk factors evaluated. Conclusion: We identified no criteria for contrast-induced nephropathy after CT; nor did we find AKI to be associated with the classical risk factors.

Resumo Objetivo: Determinar a incidência de nefropatia induzida por contraste intravenoso em pacientes hospitalizados submetidos a tomografia computadorizada (TC). Materiais e Métodos: Estudo de coorte retrospectivo que alocou 1.238 pacientes submetidos a TC sem ou com contraste (iopromida). O desfecho primário foi nefropatia induzida por contraste, definida pelo critério antigo - aumento absoluto ou relativo na creatinina sérica (SCr) ≥ 0,5 mg/dL ou ≥ 25%, respectivamente, durante 2-3 dias após a administração -, e o novo, Kidney Disease Improving Global Outcomes (KDIGO) - aumento absoluto ou relativo na SCr ≥ 0,3 mg/dL ou ≥ 50%, respectivamente, durante 2-7 dias após a administração. Resultados: A incidência de lesão renal aguda foi de 11,52% aplicando os critérios KDIGO. A regressão logística univariada demonstrou significância relacionada à associação entre aumento absoluto da SCr ≥ 0,5 mg/dL após TC e lesão renal aguda. A regressão logística multivariada encontrou, inicialmente, associação entre aumento absoluto da SCr ≥ 0,3 mg/dL após TC e idade avançada, mas a associação não foi mantida após correção. Não foi encontrada associação entre lesão renal aguda e os fatores de risco avaliados. Conclusão: Não foram encontrados critérios para nefropatia induzida por contraste após TC ou associação de lesão renal aguda com fatores de risco clássicos.

Is the penetration of clindamycin into the masseter muscle really enough to treat odontogenic infections?

OBJECTIVES: This study aims to determine the penetration of clindamycin into the masseter muscle of rats by microdialysis and correlate with the main microorganisms involved in odontogenic infections. MATERIALS AND METHODS: Tissue concentrations of clindamycin in healthy muscle tissue were measured by microdialysis after administration of a single intravenous dose of 51 mg/kg and multiple doses of 17 mg/kg (8/8 h). It was quantified in plasma after a single administration of 51 mg/kg. Microdialysis samples were collected at 30-min intervals and clindamycin was assayed by LC-MS. Pharmacokinetic parameters and tissue penetration were determined. Pharmacokinetic/pharmacodynamic index (ƒ%T > minimum inhibitory concentration (MIC)) was considered to assess dosing regimens. RESULTS: The pharmacokinetic parameters determined by non-compartmental plasma analysis for the dose of 51 mg/kg were similar to that determined by compartmental analysis. The maximum free interstitial concentration (Cmax) of clindamycin in muscle tissue was 14.20 (10.63-14.89) and 4.82 (3.35-6.66) mg/L for 51 mg/kg and 17 mg/kg 8/8 h, respectively. In addition, the area under the curve (AUC0-inf) for plasma and tissue of clindamycin were 44.78 (28.82-65.65) and 16.54 (13.83-18.35) h.mg/L for 51 mg/kg, respectively, and the tissue penetration factor determined was 1.10. Considering that the main bacteria that cause odontogenic infections generally present MIC ≤ 0.5 mg/L, the ƒ%T > MIC index is reached when the dose regimen of 17 mg/kg 8/8 h is employed. CONCLUSIONS: This investigation showed that clindamycin excellently penetrates muscle tissue of rats. It provides effective antibacterial concentrations at the target site when 17 mg/kg 8/8 h is employed and can be applied to treat the main bacteria causing odontogenic infections. CLINICAL RELEVANCE: It reinforces the use of clindamycin in odontogenic infections with significant tissue penetration.

Application of an LC-ESI-QTOF-MS method for evaluating clindamycin concentrations in plasma and prostate microdialysate of rats.

Clindamycin is used for infections caused by Gram-positive and Gram-negative anaerobic pathogens and Gram-positive aerobes. Propionibacterium acnes is an important opportunistic microorganism of the human skin and is related to prostatitis. An LC-electrospray ionization-quadrupole time-of-flight-MS method was validated for determining clindamycin concentrations in plasma and prostate microdialysate. Clindamycin separation was carried out on a C18 column at 0.5 mL/min. The mobile phase employed gradient elution of formic acid and methanol. A mass spectrometer was operated in positive electrospray ionization mode to monitor ion 425.1784 and 253.1152 for clindamycin and cimetidine (internal standard), respectively. Linearity was obtained at 0.5-10.0 µg/mL (plasma) and 0.05-1.0 µg/mL (microdialysate) with coefficients of determination ≥0.999. The intra- and inter-day precision (coefficient of variation - CV%) values were ≤13.83% and 12.51% for plasma, respectively, and ≤10.90% and 9.35% for microdialysate, respectively. The accuracy was between 90.82% and 108.25% for plasma, and 96.97% and 106.98% for microdialysate. The present method was fully validated and applied to investigate clindamycin concentrations in both plasma and prostate by microdialysis in Wistar rats (80 mg/kg, intravenous). Because the penetration of antibiotics into the prostate may be restricted, this method allows us to investigate the prostate concentrations of clindamycin for the first time.

Time-kill curves of daptomycin and Monte Carlo simulation for the treatment of bacteraemia caused by Enterococcus faecium.

OBJECTIVES: The aim of this study was to investigate the effect of daptomycin against vancomycin-resistant Enterococcus faecium bacteraemia using computer modelling. METHODS: Data obtained in vitro from time-kill curves were evaluated by PK/PD modelling and Monte Carlo simulations to determine the logarithmic reduction in the number of colony-forming units (CFU)/mL over 18 days of daptomycin treatment at 6, 8, and 10 mg/kg doses every 24 or 48 h and with variations in creatinine clearance (CLCR) of 15-29, 30-49, and 50-100 mL/min/1.73 m2. Monte Carlo simulations were performed to evaluate the probability of target attainment (PTA) for an area under the unbound drug concentration-time curve/minimum inhibitory concentration (fAUC/MIC) > 36 at the same doses and CLCR. RESULTS: Static time-kill model was employed to investigate the antibacterial efficacy of constant daptomycin concentrations. The time-kill curve analysis was performed using mathematical modelling based on a Hill coefficient factor. There was an expressive reduction (> 2 Log CFU/mL) over 18 days of daptomycin treatment in 75th percentile of individuals with CLCR of 15-100 mL/min/1.73 m2) with daptomycin 6-10 mg/kg/day, except for daptomycin every 48 h. Using fAUC/MIC > 36, PTA was > 90% at MICs ≤ 2 µg/mL. CONCLUSIONS: Higher daptomycin doses were associated with higher mortality in time-kill curves. The simulations indicated that independent of the CLCR the therapeutic responses of VRE occur with doses of daptomycin ≥ 6 mg/kg/day and daptomycin every 48 h is insufficient to treat enterococcal bacteraemia.

Antinociceptive and antioxidant effects of extract enriched with active indole alkaloids from leaves of Tabernaemontana catharinensis A. DC.

ETHNOPHARMACOLOGICAL RELEVANCE: Ethnopharmacological knowledge is important for the identification of active compounds from natural products. Pain may have different aetiologies with complex mechanisms. Tabernaemontana catharinensis A. DC. is well known for indole alkaloids, being used empirically in folk medicine, with antimicrobial and anti-inflammatory as well as antiofidic actions among others. AIM OF THE STUDY: This work aims to evaluate the antinociceptive and antioxidant effect in mice of the alkaloids extract from leaves of Tabernaemontana catharinensis A. DC. (AITc). MATERIALS AND METHODS: The AITc was produced by ultrasound and acid-base extraction, and the chemical composition was evaluated by high resolution mass spectrometry. Male mice (Mus musculus), Swiss, were used for in vivo tests. The AITc was administrated at doses of 1.0, 5.0, and 10.0 mg/kg in acetic acid model, formalin, tail-immersion, hot plate, and open field tests, and compared to saline, morphine, or diazepam controls, depending on the test. The toxicological, biochemical, haemogram and antioxidant effect were evaluated in mouse organs such as liver, brain, kidneys, spleen and stomach. RESULTS: In total, 10 compounds were identified in the AITc, being from the indole alkaloids from the ibogan and corynanthean classes. The extract in doses ranging from 5.0 to 10.0 mg/kg showed an antinociceptive effect for acetic acid, inhibiting by 47.7% and 61.6%. In the same line, reductions of 47.1% (first phase) and 43.6% (second phase) were observed for the 5.0 mg/kg dose in the formalin test. However, tail-immersion and hot plate tests did not show considerable modifications in the latency period, while in the open field test there was an inhibition of only 5.1%. It was observed no differences in NO levels and total antioxidant status of the mice in any of the studie tissues. CONCLUSIONS: The results justify the use of this plant in traditional medicine. in vivo tests indicate that these compounds possess central and peripheral mechanisms of action. This is study that reports the nociceptive action of these alkaloids, also including toxicity tests, which are intended to guarantee the safety of use of extracts of this plant.

Bacterial cellulose membrane associated with red propolis as phytomodulator: Improved healing effects in experimental models of diabetes mellitus.

Since early times, propolis has been used in folk medicine. The red propolis, collected in the northeast region of Brazil has been highlighted due to its popular use as an antimicrobial, with anti-inflammatory and healing properties, which are associated with its chemical composition. Here, we combine a bacterial membrane with red propolis to treat wounds of diabetic mice. This work aims to evaluate a biocurative from bacterial cellulose associated with red propolis in diabetic mice as wound healing model. Biocuratives from bacterial cellulose membrane and different extracts of red propolis were produced. The qualification and quantification of the presence of propolis chemical compounds in the membrane were investigated through high-resolution mass spectrometry (HRMS). Tests in vivo with biocuratives were performed on Swiss male diabetic mice induced by estroptozotocin. The animals were submitted to a surgical procedure and a single lesion was produced in the dorsal region, which was treated with the biocuratives. Macroscopic assessments were performed at 2, 7 and 14 postoperative days, and biopsies were collected on days 0, 7 and 14 for histological analysis, myeloperoxidase enzyme activity (MPO) and cytokines (TNF-α, IL-1ß, and TGF-ß). Altogether, ten compounds were identified in membranes and five were further quantified. The ethyl acetate extract showed more red propolis markers, and the most prevalent compound was Formononetin with 4423.00-2907.00 µg.g-1. Macroscopic analyses demonstrated that the two groups treated with red propolis (GMEBT and GMEAE) showed significantly greater healing capabilities compared to the control groups (GS and GMS). An increase in leukocyte recruitment was observed, confirmed by the activity of the enzyme myeloperoxidase (MPO) in GMEBT and GMEAE groups. The levels of TNF-α were significantly higher in wounds stimulated with red propolis, as well as in TGF-ß (GMEBT and GMEAE) on day 7. This was different from the IL-1ß levels that were higher in the control groups (GS and GMS). In summary, the biocuratives produced in this work were able to accelerate the wound healing process in a diabetic mouse model. In this way, the traditional knowledge of red propolis activity helped to create a biotechnological product, which can be used for diabetic wound healing purpose.

Efavirenz dissolution enhancement III: Colloid milling, pharmacokinetics and electronic tongue evaluation.

Efavirenz (EFV), a non-nucleoside reverse transcriptase inhibitor (NNRTI), is part of first-line therapy for the treatment of human immunodeficiency virus type 1 infection (HIV-1/AIDS). This drug shows relatively low oral absorption and bioavailability, as well as high intra- and inter-subject variability. Several studies have shown that treatment failure and adverse effects are associated with low and high EFV plasma concentrations, respectively. Some studies suggest different EFV formulations to minimize inter-patient variability and improve its solubility and dissolution; however, all of these formulations are complex, using for instance, cyclodextrins, dendrimers and polymeric nanoparticles, rendering them inviable industrially. The aim of this work was to prepare simple and low-cost suspensions of EFV for improvement of solubility and dissolution rate by using colloid mill, spray or freeze-drying, and characterization of the powders obtained. The results demonstrated an increase in the dissolution rate of EFV, using 0.2% of sodium lauryl sulfate (SLS) and 0.2% of hydroxypropylcellulose (HPC) or hydroxypropylmetilcellulose (HPMC) in both freeze and spray dried powders. The pharmacokinetic studies demonstrated improved pharmacokinetic parameters for the formulation containing SLS and HPC. The powders obtained, which present enhanced dissolution properties, can be incorporated in a solid dosage form for treatment of AIDS in paediatric patients with promising results.

Effect of hyperbaric oxygen therapy on tooth extraction sites in rats subjected to bisphosphonate therapy-histomorphometric and immunohistochemical analysis.

OBJECTIVE: This study aimed to investigate the effect of hyperbaric oxygen therapy (HBOT) on tooth extraction sites in rats treated with bisphosphonate. MATERIALS AND METHODS: Rats were treated with zoledronic acid, subjected to tooth extractions and allocated into groups: (1) 7 days of HBOT, (2) 14 days of HBOT, (3) 7-day control, and (4) 14-day control. The site of tooth extractions was analyzed by histomorphometry and immunohistochemistry. RESULTS: On macroscopic analysis, HBOT did not significantly affect bone exposure volume either at 7 or 14 days. On hematoxylin and eosin (H&E) analysis, the 14-day HBOT group showed less non-vital bone compared to both controls and 7-day HBOT group. HBOT significantly lowered expression of vascular endothelial growth factor (VEGF), receptor activator NF-kB ligand (RANKL), bone morphogenetic protein-2 (BMP-2), and osteoprotegerin (OPG) at 7 days, compared to control, whereas at 14 days, there was no significant difference for these variables. CONCLUSION: HBOT can reduce the amounts of non-vital bone microscopically detected in tooth extraction sites of rats subjected to bisphosphonate therapy. The effect seems to occur in a dose-dependent mode. Further studies are required to clarify the mechanisms accounting for this effect. CLINICAL RELEVANCE: Treatment of bisphosphonate-related osteonecrosis of the jaw (BRONJ) has been a challenging task, where the effectiveness of HBOT is controversial. This study reports important effects of HBOT on the maxillae of rats subjected to bisphosphonate treatment, making an important contribution to the knowledge about the applicability of HBOT in BRONJ.

Pullulan as a stabilizer agent of polymeric nanocapsules for drug delivery

ABSTRACT Polymeric stabilizers have received attention in the preparation of nanostructured systems due to their ability to enhance formulation stability. Considering this, the objective of this work was to prepare poly(ε-caprolactone) nanocapsules using the pullulan as a polymeric stabilizer. The nanocapsules were prepared using the interfacial deposition method of preformed polymers and they were characterized in terms of pH, average diameter, polydispersity index, zeta potential, beclomethasone dipropionate content, encapsulation efficiency, photostability and drug release profiles. The formulations showed physicochemical characteristics consistent with nanocarriers for drug delivery such as: average diameter lower than 270 nm, polydispersity indexes lower than 0.2, negative zeta potential (-22.7 to -26.3 mV) and encapsulation efficiencies close to 100%. In addition, the nanocapsules were able to delay the beclomethasone dipropionate photodegradation under UVC radiation and by the dialysis bag diffusion technique, the nanocapsules were able to prolong the drug release. Thus, pullulan could be considered an interesting excipient to formulate polymeric nanocapsules.

Stability-indicating RP-HPLC method for determination of beclomethasone dipropionate in nanocapsule suspensions

abstract A simple stability-indicating RP-HPLC/UV method was validated for determination of beclomethasone dipropionate (BD) in nanocapsule suspensions. Chromatographic conditions consisted of a RP C18column (250 mm x 4.60 mm, 5 µm, 110 Å), using methanol and water (85:15 v/v) as mobile phase at 1.0 mL/min with UV detection at 254 nm. The calibration curve was found to be linear in the concentration range of 5.0-25.0 µg/mL with a correlation coefficient > 0.999. Precision was demonstrated by a relative standard deviation lower than 2.0%. Accuracy was assessed by the recovery test of BD from nanocapsules (98.03% to 100.35%). Specificity showed no interference from the components of nanocapsules or from the degradation products derived from acid, basic and photolytic conditions. In conclusion, the method is suitable to be applied to assay BD in bulk drug and in nanocapsules, and it can be employed to study stability and degradation kinetics.

resumo Um método simples de CLAE-FR/UV indicativo de estabilidade foi validado para a determinação do dipropionato de beclometasona (BD) em suspensões de nanocápsulas. As condições cromatográficas foram: coluna C18 fase reversa (250 mm x 4,60 mm, 5 µm, 110 Å), usando como fase móvel metanol e água (85:15 v/v) a 1,0 mL/min, com detecção UV a 254 nm. A curva de calibração foi linear no intervalo de 5,0-25,0 µg/mL com coeficiente de correlação >0,999. A precisão foi demonstrada por um desvio padrão relativo menor que 2,0%. A exatidão foi avaliada pelo teste de recuperação do BD a partir das nanocápsulas (98,03% a 100,35%). O teste de especificidade não mostrou interferência dos componentes das nanocápsulas e nem dos produtos de degradação derivados de condições ácidas, básicas e fotolíticas. Em conclusão, o método é adequado para ser aplicado na avaliação do BD puro e em nanocápsulas e pode ser empregado para o estudo de estabilidade e degradação cinética.

Beclomethasone Dipropionate-Loaded Polymeric Nanocapsules: Development, In Vitro Cytotoxicity, and In Vivo Evaluation of Acute Lung Injury.

The aim of this work was to develop polymeric nanocapsules intended for the pulmonary delivery of beclomethasone dipropionate using ethyl cellulose or poly(ε-caprolactone). The formulations showed adequate physicochemical characteristics, namely, average diameter lower than 260 nm, low polydispersity index (< 0.2), negative zeta potential, neutral pH values, and encapsulation efficiencies close to 100%. The thermal analysis by DSC suggested that beclomethasone dipropionate encapsulated in the nanocapsules was in an amorphous state. In addition, both ethyl cellulose and poly(ε-caprolactone) nanocapsules were able to delay the drug photodegradation under UVC radiation. The in vitro drug release showed a prolonged release without burst effect using the dialysis bag diffusion technique. Moreover, ethyl cellulose and poly(ε-caprolactone) nanocapsules presented low in vitro cytotoxicity on 3T3 fibroblasts cells. In vivo, the formulations showed no acute pulmonary injury in rats. Therefore, the developed nanocapsules could be considered suitable carriers to be used for beclomethasone dipropionate pulmonary delivery.

Galenic approaches in troubleshooting of glibenclamide tablet adhesion in compression machine punches.

This study aimed to examine the adhesion of glibenclamide 5 mg tablets to the tools of compression machines. This problem is not commonly reported in the literature, since it is considered as tacit knowledge. The starting point was the implementation of three technical alternatives: changing the parameters of compression, evaluating the humidity of the powder blend and the manufacturer of the lubricant magnesium stearate. The adhesion was directly related to the characteristics of magnesium stearate from different manufacturers, and the feasibility of evaluating powder flow characteristics by different techniques that are not routinely followed in various pharmaceutical companies. In vitro dissolution tests showed that the magnesium stearate manufacturer can influence on the dissolution profile of glibenclamide tablets. This study presented various aspects of tablet adhesion to compression machine punches. Troubleshooting approaches can be, most of times, conducted based on previous experience, or an experimental research needs to be implemented in order to have confident results.

Validation of an efficient LC-microdialysis method for gemifloxacin quantitation in lung, kidney and liver of rats.

A liquid chromatography method has been established for the reliable determination of unbound gemifloxacin concentrations in kidney, lung and liver microdialysates of rats. Microdialysis probes were inserted into tissues of rats, and then dialysates were collected at regular time intervals after intravenous administration of gemifloxacin (40 mg kg(-1)). A pilot study was performed to assess gemifloxacin penetration in lung, kidney and liver of rats. Gemifloxacin was separated on a C(18) column eluted using triethylamine solution (0.5%, v/v), adjusted to pH 3.0±0.1 with 85% phosphoric acid, methanol and acetonitrile (71:15:14, v/v/v) as mobile phase at a flow rate of 1.1 mL min(-1). The fluorescence detector was set at excitation and emission wavelengths of 344 nm and 399 nm, respectively. The limit of quantitation was found to be 50 ng mL(-1). Linearity was found to be over a concentration range of 50-2000 ng mL(-1). The intra-assay and inter-assay precision and accuracy values were determined from the analysis of six quality control samples. The results obtained at three concentration levels showed R.S.D. values lower than 6.06% and 4.10% for repeatability and intermediate precision, respectively. The accuracy (R.E.%) ranged from 90.0 to 106.5%. The chromatographic run time of each sample was performed in 9 min. Drug stability in microdialysates was shown at room temperature for 8h, after three freeze-thaw cycles, in freezer at -80 °C for 14 days, and in the autosampler after processing for 8h. The relative recoveries determined by extraction efficiency (EE) and retrodialysis (RD) in vitro employing a flow rate of 1.5 µL min(-1) were 29.24±3.67% and 23.67±3.31%, respectively. In vivo recoveries determined by RD in Wistar rats' kidney, lung and liver were 27.69±2.09%, 23.12±3.79% and 17.38±0.68%, respectively. The method was successfully applied to investigate tissue penetration of unbound gemifloxacin into the kidney, lung and liver of rats.

Reversed phase liquid chromatography method with fluorescence detection of gemifloxacin in rat plasma and its application to the pharmacokinetic study.

A simple, accurate and precise high-performance liquid chromatographic method with fluorescence detection was developed and validated for the determination of gemifloxacin (GEM) in rat plasma using furosemide as internal standard (I.S.). Plasma samples were pretreated by direct deproteinization and all samples and standard solutions were chromatographed at 45°C using triethylamine solution (0.5%, v/v, pH 3.0±0.1), methanol and acetonitrile (63:30:7, v/v/v) as the mobile phase. Chromatographic resolution was achieved using a RP-C(18) column (Atlantis, Waters, 150 mm × 4.6 mm, 5 µm) at a flow rate of 1.0 mL min(-1) and an injection volume of 30 µL. The analytes were measured by fluorescence detection with excitation and emission wavelengths of 344 nm and 399 nm, respectively. The retention times for GEM and I.S. were approximately 7.5 and 12.6 min, respectively. The lower limit of quantitation (LLOQ) was 20 ng mL(-1) and the calibration curves were linear over a concentration range of 20-5000 ng mL(-1). The intra- and inter-day precisions, expressed by relative standard deviation (R.S.D.) were lower than 6.24% and 4.49%, respectively. The accuracy ranged from 91.3% to 112% and from 98.8% to 106% for the lower and upper limit of quantitation of the calibration curve, respectively. Ratio of peak area of analyte to I.S. was used for quantification of plasma samples. No interferences from endogenous substances were found. The recovery of GEM and I.S. from plasma was greater than 90%. Drug stability in plasma was shown at room temperature for 4h, after three freeze-thaw cycles for 24h, in freezer at -80°C for 60 days, and in the autosampler after processing for 12h. The utility of the assay was confirmed by the successful analysis of plasma samples from GEM pharmacokinetics studies in the rats after intravenous administration.