Lung Tissue Concentrations Research Articles

Swellable ciprofloxacin-loaded nano-in-micro hydrogel particles for local lung drug delivery.

Incorporation of drug-loaded nanoparticles into swellable and respirable microparticles is a promising strategy to avoid rapid clearance from the lung and achieve sustained drug release. In this investigation, a copolymer of polyethylene glycol grafted onto phthaloyl chitosan (PEG-g-PHCs) was synthesized and then self-assembled with ciprofloxacin to form drug-loaded nanoparticles. The nanoparticles and free drug were encapsulated into respirable and swellable alginate micro hydrogel particles and assessed as a novel system for sustained pulmonary drug delivery. Particle size, morphology, dynamic swelling profile, and in vitro drug release were investigated. Results showed that drug-loaded nanoparticles with size of 218 nm were entrapped into 3.9-μm micro hydrogel particles. The dry nano-in-micro hydrogel particles exhibited a rapid initial swelling within 2 min and showed sustained drug release. Preliminary in vivo pharmacokinetic studies were performed with formulations delivered to rats by intratracheal insufflation. Ciprofloxacin concentrations in plasma and in lung tissue and lavage were measured up to 7 h. The swellable particles showed lower ciprofloxacin levels in plasma than the controlled group (a mixture of lactose with micronized ciprofloxacin), while swellable particles achieved higher concentrations in lung tissue and lavage, indicating the swellable particles could be used for controlling drug release and prolonging lung drug concentrations.

Effects of three hydrogen-rich liquids on hemorrhagic shock in rats

BackgroundHydrogen-rich saline provides a high concentration of hydrogen, which selectively reduces levels of hydroxyl radicals and alleviates acute oxidative stress in many models. We investigated the protective effects and mechanisms of three different hydrogen-rich liquid resuscitation preparations on lung injury-induced uncontrolled-hemorrhagic shock (UHS) in rats. Materials and methodsA UHS rat model was prepared using the method of Capone et al. of arterial bleeding and tail amputation. Healthy male Wistar rats were randomly divided into seven groups (10 per group) to receive: sham treatment; Ringer solution; hydrogen-rich Ringer solution (H-Ringer solution); hydroxyethyl starch (HES); hydrogen-rich hydroxyethyl starch (H-HES); hypertonic saline/hydroxyethyl starch (HSH); and hydrogen-rich hypertonic saline/hydroxyethyl starch (H-HSH). At 72 h after successful resuscitation, lung tissue was Hematoxylin Eosin stained to score any pathologic changes. We also determined wet-to-dry (W/D) lung weight ratios and lung tissue concentrations of interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-10, malondialdehyde (MDA), and superoxide dismutase (SOD) and myeloperoxidase (MPO) activities. ResultsCompared with the non-H groups, polymorphonuclear neutrophil accumulation in alveoli in the H groups was significantly reduced (P value), and capillary leakage and wall edema were ameliorated. Compared with the sham group, pathologic pulmonary injury scores, W/D ratios, IL-6, TNF-α, IL-10, MDA concentrations, and MPO activity in the other groups were all increased, whereas SOD activity was decreased (P < 0.01). Comparing the H-Ringer, H-HES, and H-HSH groups respectively with the Ringer, HES, and HSH groups, pathologic pulmonary injury scores, W/D ratios, IL-6, TNF-α, MDA concentrations, and MPO activity were all reduced, whereas IL-10 concentrations and SOD activity were increased (P < 0.01). ConclusionsEach hydrogen-rich liquid resuscitation preparation could protect the lung against acute injury secondary to UHS. These mechanisms may be associated with hydrogen inhibiting the release of pro-inflammatory cytokines, promoting anti-inflammatory cytokine release, and reducing oxidative damage.

Red blood cells serve as intravascular carriers of myeloperoxidase

Myeloperoxidase (MPO) is a heme enzyme abundantly expressed in polymorphonuclear neutrophils. MPO is enzymatically capable of catalyzing the generation of reactive oxygen species (ROS) and the consumption of nitric oxide (NO). Thus MPO has both potent microbicidal and, upon binding to the vessel wall, pro-inflammatory properties. Interestingly, MPO – a highly cationic protein – has been shown to bind to both endothelial cells and leukocyte membranes. Given the anionic surface charge of red blood cells, we investigated binding of MPO to erythrocytes. Red blood cells (RBCs) derived from patients with elevated MPO plasma levels showed significantly higher amounts of MPO by flow cytometry and ELISA than healthy controls. Heparin-induced MPO-release from patient-derived RBCs was significantly increased compared to controls. Ex vivo experiments revealed dose and time dependency for MPO-RBC binding, and immunofluorescence staining as well as confocal microscopy localized MPO–RBC interaction to the erythrocyte plasma membrane. NO-consumption by RBC-membrane fragments (erythrocyte “ghosts”) increased with incrementally greater concentrations of MPO during incubation, indicating preserved catalytic MPO activity. In vivo infusion of MPO-loaded RBCs into C57BL/6J mice increased local MPO tissue concentrations in liver, spleen, lung, and heart tissue as well as within the cardiac vasculature. Further, NO-dependent relaxation of aortic rings was altered by RBC bound-MPO and systemic vascular resistance significantly increased after infusion of MPO-loaded RBCs into mice. In summary, we find that MPO binds to RBC membranes in vitro and in vivo, is transported by RBCs to remote sites in mice, and affects endothelial function as well as systemic vascular resistance. RBCs may avidly bind circulating MPO, and act as carriers of this leukocyte-derived enzyme.

Lung and Serum Teicoplanin Concentration After Aerosol and Intravenous Administration in a Rat Model

Ventilator-associated pneumonia (VAP) caused by methicillin-resistant Staphylococcus aureus is a major cause of mortality in mechanically ventilated patients. Nebulization of teicoplanin is an alternative way of administration that may provide higher lung tissue concentrations than intravenous (IV) delivery. The aim of this study was to compare the administration of teicoplanin via aerosol with the IV route by measuring the lung and the serum teicoplanin concentrations in a rat model. Eighty healthy male Sprague-Dawley rats were anesthetized and received a single dose of teicoplanin by the IV or aerosol route. After sacrifice, lung and blood samples were collected and teicoplanin concentrations were measured with fluorescence polarization. A noncompartmental approach was used. The area under the concentration curve/minimal inhibition concentration ratio (AUC/MIC), AUC, absorbed fraction, mean residence time (MRT), and mean absorption time (MAT) of teicoplanin were calculated. Mean±SD lung tissue concentrations of teicoplanin in the aerosol group were significantly higher than those in the IV group (p<0.0001). The mean lung tissue concentration achieved at 15 min was 1.94±1.33 mg/g in the aerosol group and 0.04±0.01 mg/g in the IV group. The mean AUClung was 67.4 mg hr(-1)g(-1) after aerosol and 0.8 mg hr(-1)g(-1) after the IV route. In the aerosol group, AUCserum/MIC ratio was 605/2, and in the IV route, AUCserum/MIC ratio was 682/2. MAT was longer after aerosol than after the IV route (0.91 hr versus 0.06 hr), and MRT was longer after aerosol than after IV bolus administration (6.52 hr versus 5.61 hr). Teicoplanin concentrations in the lung tissue of the rat model were significantly higher by the aerosol route than by the IV route. The AUClung after nebulization was 84 times higher than delivery by the IV route, and the AUClung/MIC ratio after nebulization met the recommended target to eradicate Staphylococcus aureus. Administration of teicoplanin by the aerosol route could represent one of the new therapeutic weapons of the treatment of the VAP.

Drug concentration in lung tissue in multidrug-resistant tuberculosis

To the Editor: Multidrug-resistant tuberculosis (MDR-TB) is emerging worldwide, with 3.7% of new cases and 20% of previously treated tuberculosis (TB) cases having MDR-TB. Unfortunately, second-line TB drugs, used for MDR-TB treatment, are less effective than first-line drugs [1]. Sputum culture rather than sputum smear microscopy is recommended to monitor treatment response [1]. Therapeutic drug monitoring (TDM), which may help optimise efficacy and minimise side-effects with the potential to safeguard intestinal absorption of drugs [2], is currently not recommended in World Health Organization (WHO) treatment guidelines [1]. Although TDM yields information on serum drug concentrations, penetration of second-line TB drugs into diseased tissues such as destroyed lung tissue has, to our knowledge, not been addressed in studies [3]. Herein, we report simultaneous blood and tissue concentrations of second-line TB drugs in lung tissue destroyed by MDR-TB. A 13-year-old Somalian, HIV sero-negative female, residing in the Netherlands since 2010, was admitted to our TB Unit (TB Center Beatrixoord, University Medical Center Groningen, Groningen, the Netherlands) in September 2011 with a 3-month history of cough, fever, chest pain and unintentional 14 kg weight loss. TB contacts were denied and she had not received a bacilli Calmette–Guerin vaccination. Apart from almost absent breathe sounds and dullness to percussion over the left lung field her physical examination was normal. Chest radiography showed infiltrates in the left lung, particularly in the left upper lobe. Sputum microscopy revealed acid-fast bacilli, and she was started on TB treatment with isoniazid, rifampicin, pyrazinamide and ethambutol. 2 weeks later, molecular diagnostic tests revealed mutations in both the katG and rpoB genes. MDR-TB was now considered and she was transferred to our hospital (University …

Age-dependent accumulation of heavy metals in liver, kidney and lung tissues of homing pigeons in Beijing, China

Biomonitoring provides direct evidence of the bioavailability and accumulation of toxic elements in the environment. In the current study, 1-2, 5-6, and 9-10+ year old homing pigeons collected from the Haidian District of Beijing during 2011 were necropsied and concentrations of cadmium, lead, and mercury were measured in liver, lung, and kidney tissue. At necropsy, gray/black discoloration of the margins of the lungs was observed in 98 % of the pigeons. There were no significant differences in metal concentrations as a function of gender. Cadmium concentrations in all tissues and Pb concentrations in the lung tissues were significantly greater in 9-10+ year old pigeons compared to other age groups indicating that Cd and Pb were bioavailable. Mercury concentrations were not significantly different among age groups. Cadmium concentrations in kidney and lung tissues of 9-10+ year old pigeons were similar to or exceeded concentrations of Cd reported in pigeons from another high traffic urban area and most wild avian species from Korea suggesting that Cd in this region of Beijing may be of concern. Homing pigeons provide valuable exposure and bioaccumulation data not readily available from air monitoring alone, thus providing information regarding potential health effects in wildlife and humans in urban areas. As environmental quality standards are implemented in China, homing pigeons will serve as a valuable bio-monitor of the efficacy of these actions.

Liquid chromatographic determination of CPZEN-45, a novel anti-tubercular drug, in biological samples

CPZEN-45 is a new drug candidate being considered for the treatment of tuberculosis (TB). The aim of this study was to develop and validate a reverse-phase high-performance liquid chromatographic (HPLC) method suitable to determine CPZEN-45 concentrations in biological samples. CPZEN-45 was extracted from biological fluids and tissues (plasma, lung and spleen from guinea pig) by sequential extraction with acetonitrile and quantified by a Waters HPLC Alliance System coupled with a ZORBAX Bonus-RP column, guard column and UV detection at 263nm. The mobile phase was 20:80 acetonitrile:ultrapure-water with 0.05% TFA. The CPZEN-45 peak was eluted at 5.1min with no interference from the inherent peaks of plasma, bronchoalveolar lavage (BAL), lung or spleen tissues. Recovery of CPZEN-45 from biological samples was >96% of the spiked amount. The limit of detection was 0.05μg/ml and the limit of quantitation was 0.29μg/ml which was more than 5 and 21 times lower than the reported minimal inhibitory concentration of CPZEN-45 (MIC=1.56μg/ml for Mycobacterium tuberculosis and 6.25μg/ml for MDR-TB, respectively). Thus, HPLC method was deemed reliable, sensitive, reproducible and accurate for the determination of CPZEN-45 concentrations in plasma, BAL, lung and spleen tissues. Therefore, this method was used in subsequent studies in the guinea pig model to determine the disposition of CPZEN-45 after administration of solutions by the IV and SC routes.

The dual H3/4R antagonist thioperamide does not fully mimic the effects of the ‘standard’ H4R antagonist JNJ 7777120 in experimental murine asthma

Histamine is detected in high concentrations in the airways during an allergic asthma response. In a murine model of allergic asthma, the histamine H4 receptor (H4R)-selective ligand JNJ 7777120 reduces asthma-like symptoms. A sole antagonistic function of JNJ 7777120 at the murine H4R has, however, been questioned in the literature. Therefore, in the present study, we aimed at analyzing the effects of JNJ 7777120 in comparison to that of the H3/4R-selective antagonist thioperamide. Experimental murine asthma was induced by sensitization and provocation of BALB/c mice with ovalbumine (OVA). JNJ 7777120, thioperamide, or JNJ 5207852, an H3R-selective antagonist which was used to dissect H3R- and H4R-mediated activities of thioperamide, were injected subcutaneously during sensitization and effects were analyzed after provocation. Pharmacokinetic analyses revealed shortest t1/2 values in both plasma and lung tissue and lowest maximal concentration in lung tissue for JNJ 7777120 in comparison to thioperamide and JNJ 5207852. Nevertheless, JNJ 7777120 reduced serum titers of allergen-specific (anti-OVA) IgE, inflammatory infiltrations in lung tissue, and eosinophilia in bronchoalveolar lavage fluid. In contrast, thioperamide reduced only eosinophilia in bronchoalveolar lavage fluid, while anti-OVA IgE concentrations and lung infiltrations remained unaffected. JNJ 5207852 had no effect on these parameters. JNJ 7777120 provides beneficial effects in experimental murine asthma, which, however, could only partially be mimicked by thioperamide, despite more favorable pharmacokinetics. Thus, whether these effects of JNJ 7777120 are entirely attributable to an antagonistic activity at the murine H4R or whether an agonistic activity is also involved has to be reconsidered.

A model for treating avian aspergillosis: serum and lung tissue kinetics for Japanese quail (Coturnix japonica) following single and multiple aerosol exposures of a nanoparticulate itraconazole suspension

Aspergillosis is frequently reported in parrots, falcons and other birds held in captivity. Inhalation is the main route of infection for Aspergillus fumigatus, resulting in both acute and chronic disease conditions. Itraconazole (ITRA) is an antifungal commonly used in birds, but administration requires repeated oral dosing and the safety margin is narrow. We describe lung tissue and serum pharmacokinetics of a nanoparticulate ITRA suspension administered to Japanese quail by aerosol exposure. Aerosolized ITRA (1 and 10% suspension) administered over 30 min did not induce adverse clinical reactions in quail upon single or 5-day repeated doses. High lung concentrations, well above the inhibitory levels for A. fumigatus, of 4.14 ± 0.19 μg/g and 27.5 ± 4.58 μg/g (mean ± SEM, n = 3), were achieved following single-dose inhalation of 1% and 10% suspension, respectively. Upon multiple dose administration of 10% suspension, mean lung concentrations reached 104.9 ± 10.1 μg/g. Drug clearance from the lungs was slow with terminal half-lives of 19.7 h and 35.8 h following inhalation of 1% and 10% suspension, respectively. Data suggest that lung clearance is solubility driven. Lung concentrations of hydroxy-itraconazole reached 1-2% of the ITRA lung tissue concentration indicating metabolism in lung tissue. Steady, but low, serum concentrations of ITRA could be measured after multiple dose administration, reaching less than 0.1% of the lung tissue concentration. This formulation may represent a novel, easy to administer treatment modality for fungal lung infection, preventing high systemic exposure. It may also be useful as metaphylaxis to prevent the outbreak of aspergillosis in colonized animals.

Pulmonary disposition of vancomycin nebulized as lipid vesicles in rats

Formulation of antibiotics as inhalable products is proposed to improve their therapeutic index when intended for the treatment of pulmonary infections; as vancomycin shows reduced values of lung partition coefficient, pulmonary administration might be an interesting alternative to conventional administration routes. An experimental study has been performed to compare the pulmonary disposition of vancomycin after inhalation of the drug formulated as a solution and as lipid vesicles (conventional liposomes or liposomes modified with chitosan). Vancomycin concentrations were determined in bronchoalveolar fluid, pulmonary tissue and blood samples from 27 Wistar rats distributed in three groups subjected to nebulisation of the drug formulated as a solution, conventional liposomes or chitosomes. Statistically significant differences between the mean drug concentrations in bronchoalveolar lavage (BALF) and lung tissue were found upon comparing the solution to lipid vesicles (116.95 μg ml(-1)±62.13 versus 68.34 μg ml(-1)±28.90 for liposomes and 65.36±22.11 μg g(-1) for chitosomes in BALF; 222.74±37.15 μg g(-1) versus 357.17±65.37 μg g(-1) for liposomes and 378.83±85.87 μg g(-1) for chitosomes in pulmonary tissue). The amount of available drug estimated by mass balance reached the highest values for chitosomes followed by liposomes (24289.66±4795.48 μg and 20207.91±5318.29 μg, respectively) and the lowest for the solution (18971.64±4765.38 μg). The drug transport and tissue uptake processes showed to be dependent on the nebulized formulation, being facilitated by the lipid vesicles that improved drug passage from the airway space to the pulmonary tissue and systemic circulation.

Trace and major element levels in rats after oral administration of diesel and biodiesel derived from opium poppy (Papaver somniferum L.) seeds

The study investigated the toxic effects of diesel and biodiesel derived from opium poppy (Papaver somniferum L.) oil seeds on the trace and major elements in kidney, lung, liver, and serum of rats. By the end of 21 days, trace and major element concentrations in kidney, lung, and liver tissues and the serum were measured using inductively coupled plasma-optical emission spectroscopy. We observed that trace and major element levels in kidney, lung, and liver tissues and the serum changed. Especially, important differences were detected in trace and major element concentrations in kidney and lung tissues. In kidney tissue, the concentration differences of calcium, sodium, and zinc (Zn) were found between diesel and biodiesel groups. In lung tissue, the concentration differences of cadmium, lithium, magnesium, manganese, and Zn were found between diesel and biodiesel groups. Among the significant findings, Zn concentration in serum and liver tissue of diesel and biodiesel were different from control (p < 0.05). However, the metal levels of biodiesel group were similar to control group. Due to lesser toxicity of biodiesel, it could be considered as an alternate fuel.

Long-term study of ovine pulmonary adenocarcinogenesis in sheep with marginal vs. sufficient nutritional selenium supply: Results from computed tomography, pathology, immunohistochemistry, JSRV-PCR and lung biochemistry

The impact of selenium (Se) in carcinogenesis is still debatable due to inconsistent results of observational studies, recent suspicion of diabetic side effects and e.g. dual roles of glutathione peroxidases (GPx). Previously, our group introduced long-term studies on lung carcinogenesis using the jaagtsiekte sheep retrovirus (JSRV) induced ovine pulmonary adenocarcinoma (OPA) as an innovative animal model. The present report describes the results of sufficient (0.2mg Se/kg dry weight (dw)) vs. marginal (<0.05mg Se/kg dw) nutritional Se supply on cancer progression over a two-year period in 16 animals. Computed tomography (CT) evaluation of lung cancer progression, final pathological examination, evidence of pro-viral JSRV-DNA in lung, lymph nodes and broncho-alveolar lavage cells as well as biochemical analysis of Se, GPx1 and thioredoxin reductase (TrxR) activity in lung tissue were recorded. Additionally, immunohistochemical determination of GPx1 expression in unaffected and neoplastic lung cells was implemented.The feeding regime caused significant differences in Se concentration and GPx1 activity in lung tissue between groups, whereas TrxR activity remained unaffected. JSRV was evident in broncho-alveolar lavage cells, lung tissue and lung lymph nodes. Quarterly executed CT could not demonstrate differences in lung cancer proliferation intensity. Necropsy and histopathology substantiated CT findings. Immunohistochemical analysis of GPx1 in lung tissue suggested a coherency of GPx1 immunolabelling intensity in dependence of tumour size.It was concluded that the model proved to be suitable for long-term studies of lung cancer proliferation including the impact of modifiable nutritional factors. Proliferation of OPA was unaffected by marginal vs. sufficient nutritional Se supply.

Comparative Plasma Exposure and Lung Distribution of Two Human Use Commercial Azithromycin Formulations Assessed in Murine Model: A Preclinical Study

Azithromycin (AZM) therapeutic failure and relapses of patients treated with generic formulations have been observed in clinical practice. The main goal of this research was to compare in a preclinical study the serum exposure and lung tissue concentration of two commercial formulations AZM-based in murine model. The current study involved 264 healthy Balb-C. Mice were divided into two groups (n = 44): animals of Group A (reference formulation -R-) were orally treated with AZM suspension at 10 mg/kg of b.w. Experimental animals of Group B (generic formulation -G-) received identical treatment than Group A with a generic formulation AZM-based. The study was repeated twice as Phase II and III. Serum and lung tissue samples were taken 24 h post treatment. Validated microbiological assay was used to determine the serum pharmacokinetic and lung distribution of AZM. After the pharmacokinetic analysis was observed, a similar serum exposure for both formulations of AZM assayed. In contrast, statistical differences (P < 0.001) were obtained after comparing the concentrations of both formulations in lung tissue, being the values obtained for AUC and Cmax (AZM-R-) +1586 and 122%, respectively, than those obtained for AZM-G- in lung. These differences may indicate large differences on the distribution process of both formulations, which may explain the lack of efficacy/therapeutic failure observed on clinical practice.

Tracheal responsiveness to methacholine and ovalbumin; and lung inflammation in guinea pigs exposed to inhaled lead after sensitization

The association between lead exposure and asthma is controversial. The effect of inhaled lead acetate on lung inflammation, tracheal responsiveness and immune components in guinea pigs after sensitization was examined in this study. Five groups of guinea pigs were randomly allocated to control (group C), sensitized (group S), and three test groups exposed to inhaled lead concentrations 0.1, 0.2 and 0.4M Pb after sensitization (n=6 for each group). The measured variables included tracheal responsiveness to methacholine and ovalbumin (OA); total and differential white blood cells (WBC) counts of lung lavage; serum cytokine levels (IFN-γ and IL-4); and lead concentration in lung tissue. Tracheal responsiveness to methacholine and OA; total and differential WBC counts; IL-4 and IFN-γ were significantly increased in sensitized animals compared to control group (p<0.05 to p<0.001). However, the ratio of IFN-γ/IL-4 were significantly decreased in group S (p<0.05). In addition, all measured parameters in animals exposed to highest lead concentration and most of them in animals exposed to medium lead concentration were significantly higher than group S, except for the IFN-γ and IFN-γ/IL-4 ratio, which were significantly decreased (p<0.05 to p<0.001). The lead concentration in lung tissues of all test animals was significantly higher than that of group C (p<0.001 for all groups). These results showed that lead acetate exposure can cause further increase in tracheal responsiveness to methacholine and OA, total and differential WBC count and IL-4, IFN-γ and IFN-γ/IL-4 ratio. Therefore, environmental exposure to lead may aggravate the severity of asthma.

Inhalable highly concentrated itraconazole nanosuspension for the treatment of bronchopulmonary aspergillosis

Cystic fibrosis (CF) patients are suffering from multiple often chronic endobronchial infection. The stiff mucus in these patients represents a compartment, which cannot easily be reached by systemic treatment. While bacterial infections are now successfully treated with repeated inhalation of antibiotics such as tobramycine, 57% of CF patients are colonized by Aspergillus species. About 10–20% of colonized patients develop symptoms of allergic bronchopulmonary aspergillosis (ABPA). While current standard of treatment of ABPA in CF patients is to suppress the allergy related symptoms by administration of glucocorticoids, itraconazole (ITRA), administered orally at high doses, can alleviate the symptoms of ABPA. However, no inhalable formulation of ITRA is available to enable local treatment of aspergillosis. The aim of this study was to describe an aqueous nanosuspension of ITRA and to characterize the pharmacokinetics after single dose inhalation. Using wet-milling with organic milling beads, a stable nanosuspension with particle size in the range of 200nm and an ITRA concentration of 20% (v/w) could be obtained, using polysorbate 80 at a concentration of 14% relative to ITRA. The suspension was stable if stored at 8°C for 3months without particle growth and could be nebulized using standard nebulizer technologies including mesh technology and pressured air nebulizers. A 10% suspension was well tolerated upon repeated dose inhalation once daily for 7days at a predicted dose of 45mg/kg in rats. A single dose inhalation at a predicted dose of 22.5mg/kg resulted in maximum lung tissue concentration of 21.4μg/g tissue with a terminal half-life of 25.4h. Serum concentrations were lower, with a maximum concentration of 104ng/ml at 4h after dosing and a terminal half-life of 10.5h.The data indicate that ITRA nanosuspension represents an interesting formulation for inhaled administration in CF patients suffering from ABPA. High and long lasting lung tissue concentrations well above the minimal inhibitory concentration of Aspergillus species enable once daily administration with minimal systemic exposure.

Inhibition of metastatic lung cancer in C57BL/6 mice by liposome encapsulated all trans retinoic acid (ATRA)

The purpose of this study was to investigate whether all trans retinoic acid (ATRA) incorporated in liposome composed of distearoylphosphatidylcholine (DSPC/cholesterol) could inhibit the metastatic lung cancer in mice more efficiently than free ATRA. Metastatic lung cancer model was developed by intravenous injection of B16F10 cells and it is also referred as melanoma model. In this present study, C57BL/6 mice were divided into several groups as per experimental design and the free ATRA and liposome encapsulated ATRA were given for 21days at a dose of 0.60mg/kg body weight/day after cell line implantation. After 21days, mice were sacrificed at different time interval for ATRA level analysis in serum and lung tissue by HPLC method and the remaining mice were kept for anticancer study. The ATRA level increased significantly in serum and lung tissue in liposome encapsulated ATRA treated mice. In cancer bearing mice, tumor nodule formation decreased and life span increased after receiving liposome encapsulated ATRA treatment than free ATRA treated mice. This result implies that the liposome encapsulated ATRA has maintained more ATRA concentration in lung tissue and showed more inhibition on the lung tumor nodule formation. The results indicate a possible use of liposome encapsulated ATRA in prevention of lung metastasis.

Pharmacokinetics of Tulathromycin in Healthy and Neutropenic Mice Challenged Intranasally with Lipopolysaccharide from Escherichia coli

Tulathromycin represents the first member of a novel subclass of macrolides, known as triamilides, approved to treat bovine and swine respiratory disease. The objectives of the present study were to assess the concentration-versus-time profile of tulathromycin in the plasma and lung tissue of healthy and neutropenic mice challenged intranasally with lipopolysaccharide (LPS) from Escherichia coli O111:B4. BALB/c mice were randomly allocated into four groups of 40 mice each: groups T-28 (tulathromycin at 28 mg/kg of body weight), T-7, T7-LPS, and T7-LPS-CP (cyclophosphamide). Mice in group T-28 were treated with tulathromycin at 28 mg/kg subcutaneously (s.c.) (time 0 h). The rest of the mice were treated with tulathromycin at 7 mg/kg s.c. (time 0 h). Animals in dose groups T-7-LPS and T7-LPS-CP received a single dose of E. coli LPS intranasally at -7 h. Mice in group T7-LPS-CP were also rendered neutropenic with cyclophosphamide (150 mg/kg intraperitoneally) prior to the administration of tulathromycin. Blood and lung tissue samples were obtained from 5 mice from each dose group at each sampling time over 144 h after the administration of tulathromycin. There were not statistical differences in lung tissue concentrations among groups T-7, T-7-LPS, and T7-LPS-CP. For all dose groups, the distribution of tulathromycin in the lungs was rapid and persisted at relatively high levels during 6 days postadministration. The concentration-versus-time profile of tulathromycin in lung tissue was not influenced by the intranasal administration of E. coli LPS. The results suggest that in mice, neutrophils may not have a positive influence on tulathromycin accumulation in lung tissue when the drug is administered during either a neutrophilic or a neutropenic state.

IKK NBD peptide inhibits LPS induced pulmonary inflammation and alters sphingolipid metabolism in a murine model

Airway epithelial NF-κB is a key regulator of host defence in bacterial infections and has recently evolved as a target for therapeutical approaches. Evidence is accumulating that ceramide, generated by acid sphingomyelinase (aSMase), and sphingosine-1-phosphate (S1-P) are important mediators in host defence as well as in pathologic processes of acute lung injury. Little is known about the regulatory mechanisms of pulmonary sphingolipid metabolism in bacterial infections of the lung. The objective of this study was to evaluate the influence of NF-κB on sphingolipid metabolism in Pseudomonas aeruginosa LPS-induced pulmonary inflammation.In a murine acute lung injury model with intranasal Pseudomonas aeruginosa LPS we investigated TNF-α, KC (murine IL-8), IL-6, MCP-1 and neutrophilic infiltration next to aSMase activity and ceramide and S1-P lung tissue concentrations. Airway epithelial NF-κB was inhibited by topically applied IKK NBD, a cell penetrating NEMO binding peptide. This treatment resulted in significantly reduced inflammation and suppression of aSMase activity along with decreased ceramide and S1-P tissue concentrations down to levels observed in healthy animals.In conclusion our results confirm that changes in sphingolipid metabolim due to Pseudomonas aeruginosa LPS inhalation are regulated by NF-κB translocation. This confirms the critical role of airway epithelial NF-κB pathway for the inflammatory response to bacterial pathogens and underlines the impact of sphingolipids in inflammatory host defence mechanisms.

Pharmacokinetics of sequential doses of capreomycin powder for inhalation in guinea pigs.

The global control of tuberculosis (TB) is at risk by the spread of multidrug-resistant TB (MDR TB). Treatment of MDR TB is lengthy and involves injected drugs, such as capreomycin, that have severe side effects. It was previously reported that a single daily dose of inhaled capreomycin had a positive effect on the bacterial burden of TB-infected guinea pigs. The modest effect observed was possibly due to a dose that resulted in insufficient time of exposure to therapeutic systemic and local levels of the drug. In order to determine the length of time that systemic and local drug concentrations are above therapeutic levels during the treatment period, the present study investigated the disposition of capreomycin powders after sequential pulmonary administration of doses of 20 mg/kg of body weight. Capreomycin concentrations in bronchoalveolar lavage fluid and lung tissue of animals receiving a series of one, two, or three doses of capreomycin inhalable powder were significantly higher (50- to 100-fold) at all time points than plasma concentrations at the same time points or those observed in animals receiving capreomycin solution by intramuscular (i.m.) injection (10- to 100-fold higher). Notably, at the end of each dosing period, capreomycin concentrations in the lungs were approximately 100-fold higher than those in plasma and severalfold higher than the MIC, suggesting that sufficient capreomycin remains in the lung environment to kill Mycobacterium tuberculosis. No accumulation of capreomycin powder was detected in the lungs after 3 pulmonary doses. These results indicate that the systemic disposition of capreomycin after inhalation is the same as when injected i.m. with the advantage that higher drug concentrations are present at all times in the lungs, the primary site of infection.

Simvastatin delivery via inhalation attenuates airway inflammation in a murine model of asthma

The dose–response of the pleiotropic effects of statins on airway inflammation has not yet been established and may differ from that of their cholesterol-lowering effects. High oral doses of statins may have adverse effects, and it may be possible to overcome the side effects and low clinical efficacy by administering statins via inhalation. In this study, we hypothesize that simvastatin is a potential anti-inflammatory drug with biological and pharmacokinetic properties suitable for delivery by the inhaled route. Mice were immunized with ovalbumin (OVA) and then challenged with aerosol OVA. Simvastatin was locally delivered by inhalation (i.h.) and intratracheal injection (i.t.) or systematically delivered by intraperitoneal injection (i.p.) and gavage (i.g.) during the OVA challenge. In a mouse model of asthma, i.h. simvastatin significantly and dose-dependently attenuated airway inflammation, remodeling and hyperresponsiveness in a RhoA-dependent pathway. Upon comparing the pharmacodynamics, i.h. simvastatin had a more potent effect than that of i.g. and i.p. simvastatin, and the i.h. or i.t. delivery routes led to a higher drug concentration in local lung tissue and a lower drug concentration in the plasma than that obtained by the i.g. These results suggest that simvastatin is a potential anti-inflammatory drug for airway inflammatory diseases with properties suitable for delivery by inhalation, which will probably reduce the side effects and increase clinical efficacy.