Summary: Nanoparticle drug carriers consist of solid biodegradable particles in size ranging from 10 to 1000 nm (50 -300 nm generally). They cannot freely diffuse through the bloodbrain barrier (BBB) and require receptor-mediated transport through brain capillary endothelium to deliver their content into the brain parenchyma. Polysorbate 80-coated polybutylcyanoacrylate nanoparticles can deliver drugs to the brain by a still debated mechanism. Despite interesting results these nanoparticles have limitations, discussed in this review, that may preclude, or at least limit, their potential clinical applications. Long-circulating nanoparticles made of methoxypoly(ethylene glycol)-polylactide or poly(lactide-co-glycolide) (mPEG-PLA/ PLGA) have a good safety profiles and provide drug-sustained release. The availability of functionalized PEG-PLA permits to prepare target-specific nanoparticles by conjugation of cell surface ligand. Using peptidomimetic antibodies to BBB transcytosis receptor, brain-targeted pegylated immunonanoparticles can now be synthesized that should make possible the delivery of entrapped actives into the brain parenchyma without inducing BBB permeability alteration. This review presents their general properties (structure, loading capacity, pharmacokinetics) and currently available methods for immunonanoparticle preparation.

A rapid high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed for the routine quantification of colistins A and B and their prodrugs, colistin methanesulfonate (CMS) A and CMS B, respectively, in human plasma and urine by using polymyxin B1 as the internal standard (IS). CMS concentrations were determined indirectly by subtracting the colistin concentrations determined in biological samples from the whole colistin concentrations determined after sample treatment with sulfuric acid in order to hydrolyze CMS into colistin. After extraction on a solid-phase extraction column, the colistins were separated on an XBrigde C 18 column with isocratic elution (run time .492, and 0.010 to 2.508 g/ml, respectively. In urine samples, the assay was validated over the same concentration ranges for colistins and over concentration ranges of 0.058 to 7.492 g/ml and 0.020 to 2.508 g/ml for CMSs A and B, respectively.,After being abandoned in the early 1980s because of reported nephrotoxicity and neurotoxicity (3), colistin is having a second life as a salvage treatment in critically ill patients, since it is often the last line of defense against multidrug-resistant Gram-negative bacteria, such as Pseudomonas spp. and Acinetobacter spp. (6, 15). Optimal dosing with colistin suffers from poor pharmacokinetic characterization, in part due to the challenge raised by assay of its properties when it is in biological fluids. Colistin is composed of at least 30 polymyxins, with the main fractions being colistin A (polymyxin E1) and colistin B (polymyxin E2), which account for more than 85% of colistin by weight (2,14). It is available as a sulfate salt, colistin sulfate, used orally in bowel sterilization regimens, and as a methanesulfonated inactive (1) prodrug, so-called colistimethate or colistin methanesulfonate (CMS), used as a sodium salt in parenteral and aerosol dosage forms for systemic and local treatment, respectively. The prodrug, which itself is a complex mixture of methanesulfonated colistin derivatives, mainly CMS A and CMS B, is hydrolyzed into a series of partially methanesulfonated derivatives plus colistin in vivo (12). Investigation of the pharmacokinetic behaviors of CMSs A and B and colistins A and B is therefore necessary to set up guidelines for the dosing of patients. High-pressure liquid chromatography (HPLC) methods sensitive enough for pharmacokinetic studies of colistin require complex derivatization procedures (5,7,8).Combining the quantification of colistin alone with the quantification of the whole colistin content (i.e., colistin plus methanesulfonated derivatives) permitted the determination of both the colistin and the methanesulfonated derivative concentrations in plasma samples (8). However, these HPLC methods are time-consuming (chromatographic run times are at least 15 min), and derivatization may lack interlaboratory reproducibility. Ma et al. (13) developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with electrospray ionization (ESI...

Cystic fibrosis (CF) is a complex inherited disease which affects many organs, including the pancreas and liver, gastrointestinal tract and reproductive system, sweat glands and, particularly, the respiratory system. Pseudomonas aeruginosa is the main cause of chronic airway infection. In order to reduce morbidity and mortality due to lung infection by P. aeruginosa, aerosol antibiotics have been used to achieve high local concentrations in the airways and to reduce systemic toxicity. In the course of this review, the current treatments to control CF lung infections by P. aeruginosa are presented. Some innovative aerosol formulations such as liposomes and microspheres are herein reviewed, which may improve the efficiency of anti-pseudomonal agents, and ensure patients' compliance to treatments, by reducing dosing frequency and/or drug dose, while maintaining therapeutic efficacy, preventing the occurrence of bacterial resistance and/or reducing adverse effects due to their controlled-release properties.

Lung administration of antibiotics by nebulization is promising for improving treatment efficiency for pulmonary infections, as it increases drug concentration at sites of infection while minimizing systemic side effects. For poorly soluble molecules like rifampicin, cyclodextrins (CD) may improve lung delivery by permitting higher dosing. For this purpose, we investigated rifampicin-CD complexes in terms of rifampicin apparent solubility enhancement, effect on in vitro permeability on Calu-3 broncho-alveolar cells, effect on in vitro antibacterial activity against Acinetobacter baumannii and nebulization characteristics measured by NGI cascade impactor. Complexation efficiency between rifampicin and methylated beta-cyclodextrin (RAMEB) or hydroxypropyl-beta-cyclodextrin (HPbetaCD) was pH-dependent, involving the piperazin group. Rifampicin phase solubility diagrams constructed at pH 9 showed an A(L)-type curve for RAMEB and a B(S)-type for HPbetaCD. Stability constants calculated for a 1:1 molar ratio of CD/rifampicin were 73.4 +/- 8.2 M(-1) for RAMEB and 68.5 +/- 5.2 M(-1) for HPbetaCD. Complexes with RAMEB or HPbetaCD increased 22 times and 7.6 times respectively the apparent solubility of rifampicin and were found to be satisfactorily stable for 2 days when diluted in a solution at physiological pH. The nebulization of the complex solution created droplets in size range compatible with pulmonary deposition. Furthermore, the presence of HPbetaCD decreased the MMAD of the aerosolized droplets. Activity of RAMEB and HPbetaCD complexes measured by the total rifampicin MIC against A. baumannii was similar or lower to free rifampicin MIC respectively. Complexation did not alter the rifampicin permeability in the timescale of 1h as evaluated with a Calu-3 epithelial cell model, but acted as a reservoir for rifampicin. In conclusion, this work reports that CDs can be used as vectors for pulmonary nebulization to increase the amount of active rifampicin and optimize its lung pharmacokinetic profile.

The in vitro advantage of targeted Tf vesicles did not translate into a therapeutic advantage in vivo. All vesicles reduced tumor size on day 2 but were overall less active than the free drug.

The aim of this work was to study in rats the nasal route for the brain delivery of the vasoactive intestinal peptide (VIP) neuropeptide. After evaluating VIP stability in solutions obtained from nasal washes, the effect of formulation parameters (pH 4-9, 0-1% (w/v) lauroylcarnitine (LC), hypo- or isoosmolality) on the brain uptake of intranasally administered VIP (10(-8)M)/125I-VIP (300,000 cpm/ml) was studied, using an in situ perfusion technique. Brain radioactivity distribution was assessed by quantitative autoradiographic analysis. Results were compared to intravenously administered VIP. With a hypotonic formulation at pH 4 containing 0.1% LC and 1% bovine serum albumin, VIP stability was satisfactory and loss by adsorption was minimal. Using this formulation, around 0.11% of initial radioactivity was found in the brain after 30 min perfusion and was located in the olfactory bulbs, the midbrain and the cerebellum. HPLC analysis of brain and blood extracts demonstrated the presence of intact VIP in brain and its complete degradation in the blood compartment. By intravenous administration, no intact VIP was found either in brain or in blood. In conclusion, intact VIP could be delivered successfully to the brain using the intranasal route for administration.

Moxifloxacin (MXF) is a fluoroquinolone antibiotic that is effective against respiratory infections. However, the mechanisms of MXF lung diffusion are unknown. Active transport in other tissues has been suggested for several members of the fluoroquinolone family. In this study, transport of MXF was systematically investigated across a Calu-3 lung epithelial cell model. MXF showed polarized transport, with the secretory permeability being twice as high as the absorptive permeability. The secretory permeability was concentration dependent (apparent P max ‫؍‬ 13.6 ؋ 10 ؊6 cm ⅐ s ؊1 ; apparent K m ‫؍‬ 147 M), suggesting saturated transport at concentrations higher than 350 g/ml. The P-glycoprotein inhibitor PSC-833 inhibited MXF transport in both directions, whereas probenecid, a multidrug resistance-related protein inhibitor, appeared to have no effect in the Calu-3 model. Moreover, rifampin, a known inducer of efflux transport proteins, upregulated the expression of P-glycoprotein in Calu-3 cells and enhanced MXF active transport. In conclusion, this study clearly indicates that MXF is subject to P-glycoprotein-mediated active transport in the Calu-3 model. This Pglycoprotein-dependent secretion may lead to higher MXF epithelial lining fluid concentrations than those in plasma. Furthermore, drug-drug interactions may be expected when MXF is combined with other P-glycoprotein substrates or modulators.Fluoroquinolones (FQs) are one of the main classes of antimicrobial agents, with a broad spectrum of activity and a concentration-dependent killing effect (25,29). Moxifloxacin (MXF) is an FQ that has been shown to be effective against respiratory pathogens, including Haemophilus influenzae, Moraxella catarrhalis, and penicillin-resistant strains of Streptococcus pneumoniae (3,24). The use of MXF is recommended as therapy for patients with community-acquired pneumonia, exacerbations of chronic bronchitis, chronic obstructive pulmonary disease, or tuberculosis (21). Pharmacokinetics of FQs have been studied in different tissues, such as the liver, kidney, and intestinal tract, and it appears that multiple transporters contribute to drug disposition (2). Active transport has been suggested for many FQs, involving mainly the ATP-binding cassette (ABC) transporter family (P-glycoprotein [P-gp] and multidrug resistance-related proteins [MRPs]). However, there is a lack of information regarding the mechanisms of MXF lung distribution. To our knowledge, cellular transport of MXF through the lung tissue is still unclear, and an understanding of its mechanisms would help to better predict its pulmonary disposition, which is directly linked to the bacterial killing effect. Moreover, when MXF is used as a second-line therapy or in combination with drugs such as rifampin (22), drug-drug interaction can occur, as presented in some rifampin-MXF interaction studies (23,30). In this particular case, MXF was recommended for the treatment of multidrugresistant tuberculosis and a decrease in MXF plasma concentration was observed in assoc...

Pegylated immunonanoparticles can be synthesized with bifunctional PEG derivatives that bridge the nanoparticle and the targeting MAb. This novel formulation may enable the targeted delivery of small molecules, protein drugs, and gene medicines.