Lack of dermal penetration of topically applied gentamicin as pharmacokinetic evidence indicating insufficient efficacy.

Background: Treatment of skin and superficial soft tissue infections with topically applied antibiotics is a controversial topic, because only few clinical studies exist and target site concentrations after topical treatment are widely unknown. Objectives: This study aimed to investigate the target site concentration of topically applied gentamicin as a potential cause of therapeutic failure and to explore if microporation by laser might be used to improve penetration of gentamicin through the skin barrier. Methods: Six healthy volunteers were included in this cross-over Phase 1 study. On two study days, separated by a washout period, microdialysate and plasma sampling was performed for 6 h after administration of 500 mg of gentamicin cream on a predefined area. On one of the study days the skin was microporated before drug application using the P.L.E.A.S.E. Professional laser system. Results: In intact skin, Cmax and AUC values were 3.3 ±âŸ5.64 ng/mL and 5.4 ±âŸ10.4 ng·h/mL, respectively; thereby far under the threshold needed to treat common pathogens. With a Cmax of 474.2 ±âŸ555.3 ng/mL laser application showed a significant increase in tissue penetration and decrease in pharmacokinetic variability; however, even after microporation no therapeutically active concentrations were achieved as indicated by Cmax/epidemiological cut-off ratios of 0.237 and 0.059 for Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Solely after administration on microporated skin, plasma concentrations of gentamicin were quantifiable (lower limit of quantification 10 pg/mL). Conclusions: This study confirmed that after topical administration gentamicin penetration through the dermal barrier is insufficient, providing pharmacokinetic evidence that topical gentamicin in its current form might be inappropriate to treat skin infections.

Chemical Composition and Anti-inflammatory Activity of Algerian Thymus vulgaris Essential Oil.

This work aims to elucidate the chemical composition of two essential oil (EO) samples obtained from the leaves of Thymus vulgaris L. (Lamiaceae) collected in two regions of Northwestern Algeria (Tlemcen and Mostaganem) and to assess their in vivo acute toxicity and anti-inflammatory activity. Sixty-six compounds could be identified by means of simultaneous GC-FID and GC-MS, accounting for 99.3% of total thyme oil of Mostaganem (EO.TM) and 99.0% of Tlemcen (EO.TT). In both samples, thymol was the major component, amounting to 59.5% (EO.TM) and 67.3% (EO.TT) of the total oil. EO.TT proved to be acutely toxic to mice at a dose of 4500 mg/kg p.o., whereas EO.TM did not show signs of acute toxicity, even at the highest dose tested (5000 mg/kg p.o.). Both EO samples were proven to possess anti-inflammatory activities, significantly reducing carrageenan-induced paw edema in mice (after 6 hours at a dose -of 400 mg/kg p.o) at 58.4% for EO.TT and 50.4% for EO.TM, respectively. In conclusion, it could be demonstrated that EOs of T. vulgaris exhibit a considerable in vivo anti-inflammatory activity at non-toxic doses.

Selective anticancer activity of the novel thiobenzanilide 63T against human lung adenocarcinoma cells.

Previously, it has been reported that molecules built on the benzanilide and thiobenzanilide scaffold are the promising groups of compounds with several biological activities including antifungal, antimycotic, antibacterial, spasmolytic, and anticancer ones. In this study the mechanism of action of one selected thiobenzanilide derivative N,N'-(1,2-phenylene)bis3,4,5-trifluorobenzothioamide (63T) with strongest cytotoxic activity has been investigated for the first time in human lung adenocarcinoma (A549) and normal lung derived fibroblast (CCD39Lu) in a cell culture model. The results demonstrated, that 63T can be considered a selective anticancer compound. Based on these results, several experiments including the analysis of cellular morphology, cell phase distribution, cytoplasmic histone-associated DNA fragmentation, apoptosis, necrosis, and autophagy detection were performed to understand better the mechanism underlying the anticancer activity. The data showed that 63T is a small molecule compound, which selectively induces cancer cell death in a caspase independent pathway; moreover, the autophagic dose-dependent processes may be involved in the mechanism of cell death.

Antimicrobial Activity and Chemical Analysis of the Essential Oil of Algerian Juniperus phoenicea.

The essential oils of Juniperus phoenicea L. from Algeria were obtained by hydrodistillation and analyzed by GC-FID and GC-MS. Concerning their chemical composition, 74, 61 and 72 volatile compounds were identified from fresh leaves, dried leaves and berries, representing 88.8%, 91.3% and 94.7% of the total composition, respectively. The main monoterpene in the oils of fresh leaves, dried leaves and berries was a-pinene (29.6% / 55.9% / 56.6%), accompanied by lesser amounts of the sesquiterpenes ß-caryophyllene (2.6% / 1.6% /1.2%) and germacrene D (2.01% / 1.7% / 1.5%), respectively. Antibacterial activity of J. phoenicea essential oils was tested against one Gram-negative and four Gram-positive bacterial strains and the yeast Candida albicans, responsible for nosocomial infections. As references, 14 antibiotics and 5 antifungal agents were evaluated. The berry essential oil was ineffective against all but two of the strains tested, whereas the essential oil of dried leaves significantly inhibited all strains but Pseudomonas aeruginosa, which turned out to be the most resistant strain overall. However, Escherichia coli was the most susceptible to the essential oils tested. The essential oil of dry leaves was highly active against Candida albicans, outclassing even the standard antifungal substances. These promising results could substantiate the use of essential oils in the treatment of hospital-acquired infections.

A Pilot Study on the Physiological Effects of Three Essential Oils in Humans.

In the present study, the physiological effects on 32 humans exposed to experimental stress provoked by inhalation of the essential oils of East Indian sandalwood (Santalum album L.), Western Australian sandalwood (Santalum spicatum R.Br.) and lavender (Lavandula angustifolia MILL.) were investigated. During individual testing sessions, several saliva samples were collected, blood pressure was regularly measured and parameters of the autonomic nervous system (heart rate, skin conductance response) were continuously monitored. Salivary cortisol, as an endocrine stress indicator, was determined by time- resolved fluoroimmunoassay. Statistical analyses evidenced that the tested sandalwood essential oils significantly reduced systolic blood pressure, especially during the recreation phase. This finding corresponds with a distinct reduction of salivary cortisol levels during recreation in the Western Australian sandalwood oil compared with the control. In conclusion, the results demonstrate that essential oils can alleviate the physiological reactions to psychological stress and facilitate recovery after exposition to stress.

Composition and Comprehensive Antioxidant Activity of Ginger (Zingiber officinale) Essential Oil from Ecuador.

In the present study, the chemical composition and antioxidant potential of an essential oil of ginger rhizomes from Ecuador was elucidated. The analysis of the essential oil by GC/FID/MS resulted in identification of 71 compounds, of which the main are citral (geranial 10.5% and neral 9.1%), α-zingiberene (17.4%), camphene (7.8%), α-farnesene (6.8%) and ß-sesquiphellandrene (6.7%). The in vitro antioxidant activity of the essential oil expressed by IC50 in descending order is: hydroxyl radical (OH*) scavenging (0.0065 µg/mL) > chelating capacity (0.822 µg/mL) > 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS*+) scavenging (3.94 µg/mL) > xanthine oxidase inhibition (138.0 µg/mL) > oxygen radical (O2*) scavenging (404.0 µg/mL) > 2,2- diphenyl-1-picrylhydrazyl radical (DPPH*) scavenging (675 µg/mL). Lipid peroxidation inhibition of the essential oil was less efficient than butylhydroxytoluol (BHT) in both stages, i.e. hydroperoxide and malondialdehyde formation. In vivo studies in Saccharomyces cerevisiae demonstrated a significant dose-dependent increase in antioxidant marker enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), blocking the oxidation processes in yeast cells. Moreover, ginger essential oil in concentrations of 1.6 mg/mL increases the viability of cells to oxidative stress induced by H2O2.

In Silico Predictions of Drug - Drug Interactions Caused by CYP1A2, 2C9 and 3A4 Inhibition - a Comparative Study of Virtual Screening Performance.

The cytochrome P450 (CYP) superfamily represents the major enzyme class responsible for the metabolism of exogenous compounds. Investigation of clearance pathways is therefore an integral part in early drug development, as any alteration of metabolic enzymes may markedly influence the toxicological profile and efficacy of novel compounds. In silico methods are widely applied in drug development to complement experimental approaches. Several different tools are available for that purpose, however, for CYP enzymes they have only been applied retrospectively so far. Within this study, pharmacophore- and shape-based models and a docking protocol were generated for the prediction of CYP1A2, 2C9, and 3A4 inhibition. All theoretically validated models, the validated docking workflow, and additional external bioactivity profiling tools were applied independently and in parallel to predict the CYP inhibition of 29 compounds from synthetic and natural origin. After subsequent experimental assessment of the in silico predictions, we analyzed and compared the prospective performance of all methods, thereby defining the suitability of the applied techniques for CYP enzymes. We observed quite substantial differences in the performances of the applied tools, suggesting that the rational selection of that virtual screening method that proved to perform best can largely improve the success rates when it comes to CYP inhibition prediction.

Interplay of drug metabolizing enzymes with cellular transporters.

Many endogenous and xenobiotic substances and their metabolites are substrates for drug metabolizing enzymes and cellular transporters. These proteins may not only contribute to bioavailability of molecules but also to uptake into organs and, consequently, to overall elimination. The coordinated action of uptake transporters, metabolizing enzymes, and efflux pumps, therefore, is a precondition for detoxification and elimination of drugs. As the understanding of the underlying mechanisms is important to predict alterations in drug disposal, adverse drug reactions and, finally, drug-drug interactions, this review illustrates the interplay between selected uptake/efflux transporters and phase I/II metabolizing enzymes.

Pharmacokinetics and toxicity of intrathecal liposomal cytarabine in children and adolescents following age-adapted dosing.

BACKGROUND AND OBJECTIVE: Assessment of the optimal drug dose for intrathecal therapy in children is challenging because of the non-linear increase in cerebrospinal fluid (CSF) volume throughout childhood and potential differences in the elimination rate in children versus adults. The present study was designed to prospectively collect pharmacokinetic and safety data on age-adapted intrathecal liposomal cytarabine in children aged >3 years. PATIENTS AND METHODS: Sixteen patients with malignant brain tumours were included in the study. Children aged 3-10 years received liposomal cytarabine 35 mg with concomitant dexamethasone, and those aged >10 years received 50 mg. Serial CSF and plasma samples were collected before administration and 1 h, 12 h, 24 h, 1 week and 2 weeks post-dosing. CSF was analysed for free and encapsulated cytarabine, and plasma was analysed for free cytarabine. RESULTS: The average elimination half-life values in children aged 3-10 years and in those aged >10 years, treated with liposomal cytarabine 35 mg and 50 mg, respectively, were 40.9 and 43.7 h for free cytarabine and 31.5 and 36.4 h for encapsulated cytarabine in CSF. Although these values were lower than those previously reported, cytarabine concentrations exceeded the cytotoxic threshold of 0.1 mg/L in all patients until 1 week post-intraventricular administration. Cytarabine concentrations in plasma were negligible. In general, liposomal cytarabine was well tolerated, with relevant but manageable toxicities. CONCLUSION: Liposomal cytarabine in doses of 35 mg for children aged 3-10 years and 50 mg for older patients shows sufficient drug exposure for at least 1 week and appears to be well tolerated.

Chemical Composition and Antioxidant Properties of Juniper Berry (Juniperus communis L.) Essential Oil. Action of the Essential Oil on the Antioxidant Protection of Saccharomyces cerevisiae Model Organism.

The essential oil of juniper berries (Juniperus communis L., Cupressaceae) is traditionally used for medicinal and flavoring purposes. As elucidated by gas chromatography/flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS methods), the juniper berry oil from Bulgaria is largely comprised of monoterpene hydrocarbons such as α-pinene (51.4%), myrcene (8.3%), sabinene (5.8%), limonene (5.1%) and ß-pinene (5.0%). The antioxidant capacity of the essential oil was evaluated in vitro by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging, 2,2-azino-bis-3-ethylbenzothiazoline-6 sulfonic acid (ABTS) radical cation scavenging, hydroxyl radical (ОН(•)) scavenging and chelating capacity, superoxide radical ((•)O2(-)) scavenging and xanthine oxidase inhibitory effects, hydrogen peroxide scavenging. The antioxidant activity of the oil attributable to electron transfer made juniper berry essential oil a strong antioxidant, whereas the antioxidant activity attributable to hydrogen atom transfer was lower. Lipid peroxidation inhibition by the essential oil in both stages, i.e., hydroperoxide formation and malondialdehyde formation, was less efficient than the inhibition by butylated hydroxytoluene (BHT). In vivo studies confirmed these effects of the oil which created the possibility of blocking the oxidation processes in yeast cells by increasing activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx).

Tissue pharmacokinetics of ertapenem at steady-state in diabetic patients with leg infections.

OBJECTIVES: Ertapenem pharmacokinetics were determined in the interstitium of healthy tissue and of infected tissue of patients suffering from diabetic foot infections, to evaluate if antibiotic concentrations at the target site are sufficient to achieve bacterial killing. PATIENTS AND METHODS: Nine patients with diabetic foot infections received 1 g of ertapenem per day intravenously. At steady-state, ertapenem concentrations were measured over 8 h in plasma and in the interstitium of healthy subcutaneous adipose tissue and of soft tissue adjacent to the foot infection using microdialysis. RESULTS: The maximum total concentration (Cmax) of ertapenem in plasma was 59.4 ± 12.9 mg/L. Free interstitial Cmax in the infected leg (4.5 ± 2.7 mg/L) was significantly higher (P=0.01) than in healthy subcutaneous tissue (2.4 ± 1.6 mg/L). For bacterial pathogens with an MIC of 1 mg/L, the free mean 'time above MIC' (T>MIC) in the interstitium of infected tissue was calculated to be 38%± 25% of the 24 h dosing interval. Accordingly, bacteriostatic (T>MIC >20%) and maximal bactericidal (T>MIC >40%) effects would be reached in 8/9 and 4/9 diabetic feet, respectively. CONCLUSIONS: Although total plasma concentrations of ertapenem were lower in diabetics than reported for healthy subjects, free interstitial tissue concentrations in diabetics were similar to those known from healthy volunteers. Penetration of ertapenem into the interstitium of inflamed tissue of diabetic feet was not impaired in spite of angiopathy. Daily doses of >1 g of ertapenem might be considered to optimize bactericidal effects in diabetic foot infections caused by moderately susceptible strains.

Chirality influences the effects of linalool on physiological parameters of stress.

The specific physiological responses induced by inhaling R-(-)- as well as S-(+)-linalool in 24 human subjects undergoing experimental stress were investigated in this study. Various physiological parameters of the autonomous nervous system (heart rate, blood pressure, electrodermal activity) as well as the endocrine system (salivary cortisol) were monitored. The study clearly indicated that odorants can modulate salivary cortisol levels, with both linalool enantiomers exerting relaxing effects. Concerning blood pressure and heart rate, S-(+)-linalool acted as an activating agent in contrast to electrodermal activity. R-(-)-linalool proved to be stress-relieving as determined by heart rate. In conclusion, the results revealed that (1) chirality crucially influences the physiological effects of odorants and that (2) odorants may act differently on certain physiological parameters.

Adaptation of DELFIA cortisol kit for determination of salivary cortisol concentration.

Salivary cortisol concentration seems to be an excellent indicator of the biologically active plasma cortisol level because of the nearly absence of corticoid-binding proteins in saliva. With regard to the easy, noninvasive, and stress-free nature of saliva sampling, this parameter greatly facilitates studies of the HPA (hypothalamus-pituitary-adrenocortical) axis, especially in children. A commercially available TR-FIA (time-resolved fluoroimmunoassay), the DELFIA (dissociation-enhanced lanthanide fluoroimmunoassay) method, proposed for plasma and urine cortisol analyses, was adapted for salivary cortisol measurement by means of simple modifications of the assay protocol. The sensitivity was determined to be 0.53 nmol/L. The intra- and interassay coefficients of variation ranged from 5.5 to 8.2 % and from 6.0 to 10.4 %, respectively. The present findings suggest that the DELFIA procedure provides a reliable, sensitive, and convenient alternative procedure to the assay for salivary cortisol.