Spray-dried multidrug particles for pulmonary co-delivery of antibiotics with N-acetylcysteine and curcumin-loaded PLGA-nanoparticles.

Nowadays, the resistance of bacterial biofilms towards the available antibiotics is a severe problem. Therefore, many efforts were devoted to develop new formulations using nanotechnology. We have developed an inhalable microparticle formulation using spray-drying combining multiple drugs: an antibiotic (tobramycin, ciprofloxacin or azithromycin), N-acetylcysteine (NAC), and curcumin (Cur). The use of PLGA nanoparticles (NP) also allowed incorporating curcumin to facilitate spray drying and modify the release of some compounds. The aerosolizable microparticles formulations were characterized in terms of size, morphology, and aerodynamic properties. Biocompatibility when tested on macrophage-like cells was acceptable after 20 h exposure for concentrations up to at least 32 µg/mL. Antibacterial activity of free drugs versus drugs in the multiple drug formulations was evaluated on P. aeruginosa in the same range. When co-delivered the efficacy of tobramycin was enhanced compared to the free drug for the 1 µg/mL concentration. The combinations of azithromycin and ciprofloxacin with NAC and Cur did not show an improved antibacterial activity. Bacteria-triggered cytokine release was not inhibited by free antibiotics, except for TNF-α. In contrast, the application of NAC and the addition of curcumin-loaded PLGA NPs showed a higher potential to inhibit TNF-α, IL-8, and IL-1ß release. Overall, the approach described here allows simultaneous delivery of antibacterial, mucolytic, and anti-inflammatory compounds in a single inhalable formulation and may therefore pave the way for a more efficient therapy of pulmonary infections.

[The application of N-acetylcysteine in optimization of specific pharmacological therapies]. / Zastosowanie N-acetylocysteiny do optymalizacji specyficznych terapii farmakologicznych.

Based on the analysis of data from clinical trials it could be postulated that N-acetylcysteine has a positive impact on the treatment of various diseases. However, less is known about specific molecular and physiological mechanisms underlying the reported therapeutic effects. N-acetylcysteine (NAC, N-acetyl-L-cysteine) is an amino acid derivative containing a thiol group. It is a precursor of L-cysteine and glutathione. NAC is well absorbed and safe for the body at doses up to 300 mg per kg of body weight. Side effects are relatively rare. NAC is used as an mucolytic agent in adjunctive therapy of respiratory diseases causing the retention of secretions, as well as an antidote in the treatment of paracetamol poisoning. Moreover, NAC protects against the toxic effects of reactive oxygen species and their active metabolites. NAC is involved in free radical scavenging processes via several independent mechanisms, including a direct reduction of free radicals, providing substrates for oxidation-reduction reactions and activation of antioxidant enzymes. In the blood, NAC decreases the level of low density lipoprotein peroxidation. In various tissues, NAC may increase the levels of glutathione and cysteine and stimulate the superoxide dismutase action. NAC is used as a supplement in the treatment of various diseases associated with impaired exterior and intracellular oxidative balance. NAC increases the concentrations of amino acids and their derivatives, including cysteine, cystine, and glutathione. It also stabilizes the antioxidant status of the cells and the intercellular spaces. NAC changes the levels of transcription factors, modifying the transcription of selected genes and acting on the protein translation. It works on the activation of several enzymes in the cells and outside the cells. Based on the analysis of data from clinical trials it can be concluded, that an administration of NAC may be beneficial for these groups of patients, in whom the reversible accumulation and the negative action of free radicals was observed.

Nanocomplexes for gene therapy of respiratory diseases: Targeting and overcoming the mucus barrier.

Gene therapy, i.e. the delivery and expression of therapeutic genes, holds great promise for congenital and acquired respiratory diseases. Non-viral vectors are less toxic and immunogenic than viral vectors, although they are characterized by lower efficiency. However, they have to overcome many barriers, including inflammatory and immune mediators and cells. The respiratory and airway epithelial cells, the main target of these vectors, are coated with a layer of mucus, which hampers the effective reaching of gene therapy vectors carrying either plasmid DNA or small interfering RNA. This barrier is thicker in many lung diseases, such as cystic fibrosis. This review summarizes the most important advancements in the field of non-viral vectors that have been achieved with the use of nanoparticulate (NP) systems, composed either of polymers or lipids, in the lung gene delivery. In particular, different strategies of targeting of respiratory and airway lung cells will be described. Then, we will focus on the two approaches that attempt to overcome the mucus barrier: coating of the nanoparticulate system with poly(ethylene glycol) and treatment with mucolytics. Our conclusions are: 1) Ligand and physical targeting can direct therapeutic gene expression in specific cell types in the respiratory tract; 2) Mucopenetrating NPs are endowed with promising features to be useful in treating respiratory diseases and should be now advanced in pre-clinical trials. Finally, we discuss the development of such polymer- and lipid-based NPs in the context of in vitro and in vivo disease models, such as lung cancer, as well as in clinical trials.

S-carboxymethyl-L-cysteine and it (R/S)-S-oxides in beagle dog plasma and hepatic cytosol.

1. Incubation of beagle hepatic cytosol, under conditions promoting phenylalanine hydroxylase activity, led to the formation of the sulfoxide derivatives of S-carboxymethyl-L-cysteine, N-acetyl-S-carboxymethyl-L-cysteine, S-methyl-L-cysteine and N-acetyl-S-methyl-L-cysteine. Thiodiglycolic acid was not a substrate. Enzyme kinetic parameters (Km, Vmax) were derived indicating S-carboxymethyl-L-cysteine had the greatest clearance; no enantioselective preference was observed for this S-oxygenation reaction. 2. Following oral administration of S-carboxymethyl-L-cysteine to beagle dogs, the parent substance and its sulfoxide were the only compounds identified in the plasma. Pharmacokinetic data have been obtained indicating that the small amount of sulfoxide formed persisted within the body for longer than the parent material, but that the majority of the ingested dose remained in the administered sulfide form. 3. The sulfide moiety within the muco-regulatory drug, S-carboxymethyl-L-cysteine, is thought to be vital as it acts as a free radical scavenger, resulting in the inactive sulfoxide. Additional extensive enyzme-mediated sulfoxidation would decrease the amount of active sulfide available. In the dog this appears to not be an issue, signalling possible exploitation for therapeutic benefit in treating airway disease.

Membrane permeability in the gastrointestinal tract: the interplay between microclimate pH and transporters.

Some examples of pH- and transporter-dependent permeability, determined in side-by-side diffusion cells, are summarized. We investigated the polarized transport in the mucosal-to-serosal direction of monocarboxylic acid-type drugs through the excised rat jejunal tissue and an artificial membrane. We established that, in vitro, these substances are most probably not transported by monocarboxylate transporter 1, but by passive pH-dependent transport. We also studied various influences on the permeability of fluorescein, a low permeability marker, through isolated rat intestinal segments, Caco-2 cell monolayers, and an artificial membrane. Polarized transport of fluorescein in the serosal-to-mucosal direction through the rat jejunum by multidrug resistance-associated protein was triggered by the addition of D-glucose to the mucosal side, while the pH-dependent increase of fluorescein influx is presumably the consequence of a monocarboxylate transporter and a member of the organic-anion transporting polypeptide family. With permeability experiments through the excised segments of rat small intestine, we ascertained that ciprofloxacin is a low-permeability drug and has higher and pH-dependent transport in the mucosal-to-serosal direction than in the opposite direction. We also established that neither the permeability of fluoroquinolones nor their solubility in different buffers was influenced by the interactions with metal cations.

Simultaneous detection of N-acetyl-L-cysteine and physiological low molecular mass thiols in plasma by capillary electrophoresis.

N-acetyl-L-cysteine (NAC) is a therapeutic drug widely used as mucolytic agent in the treatment of respiratory diseases. Recently it has been proposed that NAC administration may modify the plasma levels of low molecular weight thiols (LMW) like cysteine, homocysteine and glutathione, though it has been still debated if their plasma concentration increases or decreases during the therapy. Therefore research calls for methods able to analyze simultaneously NAC and the other plasma LMW thiols in order to evaluate if NAC is able to modify plasma thiols concentration and in particular to reduce homocysteine levels in hyperhomocysteinemia. In this paper we present a new capillary electrophoresis method that allows a baseline separation of plasma NAC from the physiological thiols. The proposed method has been utilized to measure the drug and the physiological LMW thiols in NAC administered chronic obstructive broncho-pneumopathy (COPB) disease patients.

Measurement of phenylalanine monooxygenase (PAH) activities.

Mammalian phenylalanine monooxygenase (phenylalaninase, phenylalanine hydroxylase, PAH; EC 1.14.16.1) is a member of the large aromatic amino acid hydrolase cohort of enzymes that include tyrosine monooxygenase and tryptophane monooxygenase. PAH is a non-heme-iron-dependent protein that normally catalyzes the C-oxidation of phenylalanine (Phe) to tyrosine (Tyr) in the presence of BH(4), utilizing molecular dioxygen as an additional substrate. However, over recent years, the presumed narrow substrate specificity of PAH has been questioned and catalytic activity towards alternative xenobiotic substrates (both environmental and drugs) has been reported. Like the cytochrome P450 system, PAH is able to oxidize both aliphatic and aromatic carbon centers in addition to undertaking the S-oxidation of aliphatic thioethers (including the two mucoactive drugs S-carboxymethyl-L-cysteine and S-methyl-L-cysteine).

Effect of COPD treatments on MRP1-mediated transport in bronchial epithelial cells.

BACKGROUND: Smoking is the principle risk factor for development of chronic obstructive pulmonary disease (COPD). Multidrug resistance-associated protein 1 (MRP1) is known to protect against toxic compounds and oxidative stress, and might play a role in protection against smoke-induced disease progression. We questioned whether MRP1-mediated transport is influenced by pulmonary drugs that are commonly prescribed in COPD. METHODS: The immortalized human bronchial epithelial cell line 16HBE14o- was used to analyze direct in vitro effects of budesonide, formoterol, ipratropium bromide and N-acetylcysteine (NAC) on MRP1-mediated transport. Carboxyfluorescein (CF) was used as a model MRP1 substrate and was measured with functional flow cytometry. RESULTS: Formoterol had a minor effect, whereas budesonide concentration-dependently decreased CF transport by MRP1. Remarkably, addition of formoterol to the highest concentration of budesonide increased CF transport. Ipratropium bromide inhibited CF transport at low concentrations and tended to increase CF transport at higher levels. NAC increased CF transport by MRP1 in a concentration-dependent manner. CONCLUSIONS: Our data suggest that, besides their positive effects on respiratory symptoms, budesonide, formoterol, ipratropium bromide, and NAC modulate MRP1 activity in bronchial epithelial cells. Further studies are required to assess whether stimulation of MRP1 activity is beneficial for long-term treatment of COPD.

Protective effects of erdosteine and vitamins C and E combination on ischemia-reperfusion-induced lung oxidative stress and plasma copper and zinc levels in a rat hind limb model.

The aim of this study was to investigate the protective effects of erdosteine and vitamins C and E (VCE) on the lungs after performing hind limb ischemia-reperfusion (I/R) by assessing oxidative stress, plasma copper (Cu), and zinc (Zn) analysis. The animals were divided randomly into four groups as nine rats each as follows: control, I/R, I/R plus erdosteine, and I/R plus VCE combination. I/R period for 60 min was performed on the both hind limbs of all the rats in the groups of I/R, erdosteine with I/R, VCE with I/R allowing 120 min of reperfusion. The animals received orally erdosteine one time in a day and 3 days before I/R in the erdosteine group. In the VCE group, the animals VCE combination received one time in a day and 3 days before I/R, although placebo was given to control and I/R group animals. Lung lipid peroxidation (malondialdehyde [MDA]) level, superoxide dismutase (SOD), and catalase activities were increased, although lung glutathione (GSH) and plasma Zn levels decreased in I/R group in lung tissue compared with the control group. Serum MDA level, creatine kinase, and lactate dehydrogenase activities were increased in I/R group compared with the control. Lung MDA and plasma Zn levels and lung SOD activity were decreased by erdosteine administration, whereas lung GSH levels after I/R increased. The plasma Zn levels and lung SOD activity were decreased by VCE administration, although the plasma Cu and lung GSH levels increased after I/R. In conclusion, erdosteine has an antioxidant role on the values in the rat model, and it has more protective affect than in VCE in attenuating I/R-induced lung injury in rats.

The SH-metabolite I of erdosteine, a mucolytic drug, enhances the inhibitory effect of salbutamol on the respiratory burst of neutrophils.

Reactive oxygen species (ROS) are a common denominator of airway inflammation associated with chronic obstructive pulmonary disease (COPD) and asthma, as well as with less frequent lung diseases such as idiopathic pulmonary fibrosis (IPF), acute respiratory distress syndrome (ARDS) and cystic fibrosis (CF). The most frequently administered drugs used to treat these diseases are bronchodilators, antioxidant/antiphlogistic agents and mucoactive drugs. The metabolization of the mucoactive drug erdosteine produces an active metabolite (Met I) with a reducing SH group. In addition to its mucolytic action, Met I also has useful antioxidant activity. The various activities of beta 2-agonists include their ability to reduce the respiratory burst of neutrophils and the subsequent release of ROS. beta 2-Agonists and mucoactive drugs may be administered to the same patients during the treatment of lung diseases. The aim of this study was to investigate the ability of Met I to potentiate the activity of salbutamol in inhibiting the in vitro respiratory burst of neutrophils by means of chemiluminescence. The combination of Met I 5 and 10 micrograms/ml with salbutamol 10(-5), 10(-6) and 10(-7) M led to a significant reduction in respiratory bursts when the neutrophils were stimulated with the soluble stimulant N-formyl-methionylleucyl-phenylalanine (fMLP). The combinations of the two drugs that reduced the respiratory bursts when a particulate stimulus (Candida albicans) was used were those containing 10(-5) M of salbutamol. The reasons for this different behavior remain unclear and raise questions about the specific roles, sites and mechanisms of action of the different types of stimulation undergone by the respiratory airways.

A review of xenobiotic metabolism enzymes in Parkinson's disease and motor neuron disease.

The role of xenobiotic metabolising enzymes (XMEs) in disease aetiology has been under investigation by numerous researchers around the world for the last two decades. The association of a number of defects in both phase I and phase II reactions with Parkinson's disease (PD) and motor neuron disease (MND) have been extensively studied. This review of the work of the group based initially at the University of Birmingham into the functional genomics of XMEs and neurodegenerative diseases has indicated that: 1. Sub-groups of patients with PD and MND can be identified with problems in xenobiotic metabolism by in vivo or in vitro methods. 2. 38-39% of the patients with MND/PD have a defect in the S-oxidation of the mucoactive drug, carbocysteine, by an unknown cytosolic oxidase(s). The odds risk ratio for the association of this defect with these diseases was calculated to be 10.21 for MND and 10.50 for PD. 3. Patients with PD appear to have an altered substrate specificity for monoamine oxidase B substrates in an in vitro platelet assay. 4. Patients with MND have an increased capacity to S-methylate aliphatic sulphydryl compounds in an in vivo challenge as well as an in vitro erythrocyte thiol methyltransferase assay. The results of over a decade of investigations into both PD and MND indicate that these are diseases with mutifactorial origins that encompass both genetic predisposition and environmental insult.

[Absorption, distribution, excretion and metabolism of 4-carbomethoxythiazolidine chlorohydrate. Biochemical experimental study in the rat]. / Assorbimento, distribuzione, escrezione e metabolismo della 4-carbometossitiazolidina cloridrato. Studio biochimico sperimentale nel ratto.

A biochemical-metabolic study has been conducted on TCM (4-carbomethoxythiazolidin hydrochloride) in rats, utilising a product traced with 14C. An in-vitro test has demonstrated that TCM is hydrolised by endogenous esterases to thiazolidincarboxylic acid, into the following decreasing order of activity: kidneys, lungs, plasma, liver, intestinal content and mucosa. Upon oral administration, TCM proved to have a good and rapid absorption and distribution level in the organs. In the beginning the liver and the kidneys have displayed higher concentrations with respect to the lungs; after 8 hours, however, the latter have displayed slightly lower concentrations than before, which were not very far from the liver's and kidneys'. TCM has been mainly eliminated through the urines (56.9% in 24 hours) and less through the feces (6.7% in the same period of time). By means of a thin-layer chromatography analysis and a mass-spectrometry it has been possible to study the metabolism of TCM. The results of both in-vitro and in-vivo tests have demonstrated that TCM is hydrolised to thiazolidin-carboxylic acid, which, in its turn, is transformed into cysteine. This last transformation does mainly occur in the liver, but significantly in the lungs as well. TCM is absorbed in part as such and in part as thiazolidincarboxylic acid. As no methyl-cysteinate has been traced, it has been assumed that the hydrolysis of the ester bond was a kinetically quicker event than the heterocycle opening.

[Metabolism of 4-carbomethoxythiazolidine chlorohydrate to cysteine through human expectorate and lung homogenates, and its action on glycoproteins of mucus]. / Metabolizzazione della 4-carbometossitiazolidina cloridrato a cisteina ad opera di espettorati ed omogenati di polmone umani e sua azione sulle glicoproteine del muco.

A study has been carried out on the formation of -SH groups and of cysteine and cystine from 4-carbomethoxythiazolidin HCl through human expectorate mucus and lung homogenates. Both the expectorate and the homogenate, revealed to be able to metabolize TCM to cysteine releasing free -SH groups. The speed of cysteine formation is higher for the homogenate, but also the expectorate revealed to be very effective for the metabolization to cysteine. Furthermore it has been demonstrated that the TCM, incubated with human expectorate in presence and in absence of lung homogenate, can modify the chemical-physical characteristics of the mucus, rendering it more soluble and less viscous, i.e. displaying a mucolytic activity. These results account for the in-vitro experimental base to the observation that the product has a mucolytic activity whether administered by os or by aerosol.

Disposition and metabolism of letosteine in rats.

The metabolism and disposition of letosteine, labeled either with 14C or 35S, has been investigated in Sprague-Dawley rats. In separate experiments, rats received 20 mg/kg, iv or orally, [14C]letosteine or [35S]letosteine. Radioactivity was rapidly excreted, mainly in urine, after iv and oral administration. Recovery of radioactivity from 0-72-hr excreta averaged 95% after both routes of [14C]letosteine administration, whereas only 50% was recovered when [35S]letosteine was administered. 14CO2 accounted for about 7.3% (iv) and 5.1% (po) of the dose of [14C]letosteine. Comparison of the iv and oral areas under the plasma 14C radioactivity concentration-time curves suggested that oral absorption of letosteine was complete. Analysis of the radioactivity content of urine showed that letosteine undergoes rapid and extensive metabolism. Several metabolites were identified by TLC, HPLC, and MS. The findings are consistent with a splitting of the ester group of letosteine and subsequent cleavage of the thiazolidinyl ring, yielding cysteine, hypotaurine, taurine, and inorganic sulfate. The metabolite derived from the side chain was identified in the urine as 3-(hydroxycarbonylmethylthio)propanoic acid. It undergoes further oxidation into sulfoxide and sulfone derivatives, which are also present in the urine.

[Bronchial expectorants : pharmacology of bronchial mucomodifiers]. / Les fluidifiants bronchiques : pharmacologie des mucomodificateurs bronchiques.

Prescription of bronchial mucus modifiers has benefited from recent advances in the knowledge of biochemical constituents of bronchial fluids, their regulation and disturbances on the one hand, and the consequences of biochemical changes in these fluids on rheological characteristics of bronchial secretions on the other. In addition, the significance of these characteristics has been evidenced by the study of mucociliary transportation. Drugs which modify bronchial fluids are studied according to their mode of action upon the organized gel phase, mobilized by ciliary activity, and the aqueous sol phase, which enables this ciliary activity. Drugs which modify the gel phase are either true mucolytic agents or muco-regulators. True mucolytic drugs include reducing agents with a free thiol group, chiefly N-acetyl-cysteine which breaks disulfide bonds linking different protein chains, and proteolytic enzymes which break protein chains. The latter also have an appreciable anti-inflammatory effect but are rarely used at present owing to allergic reactions. Mucoregulating drugs are cysteine derivatives whose thiol group is not free. They are headed by carbocysteine which activates the synthesis of sialidized acid mucins. They enable reorganization of bronchial mucus, reversing former drops in viscosity and elasticity, thereby improving mucociliary transportation. They have a complementary anti-inflammatory action.