Treatment of chronic relapsing urinary tract infection with antibiotics selected by AtbFinder.

We report the case of a 46-year-old patient who, after renal cancer surgery, developed a recurrent urinary tract infection that lasted for more than 2 years. Despite repeated antibiotic courses, including broad-spectrum drugs chosen using conventional antibiotic susceptibility testing, multiple reinfections followed. The patient was successfully treated once antibiotics were selected with AtbFinder. Unlike routine antimicrobial susceptibility methods, which select antibiotics effective only against a "lead bacterial pathogen," AtbFinder identifies antibiotics that target the mixture of bacteria at the infection site. This case demonstrates the ability of AtbFinder to successfully select antibiotics for the treatment of relapsing urinary tract infections.

Nanocapsules modify membrane interaction of polymyxin B to enable safe systemic therapy of Gram-negative sepsis.

Systemic therapy of Gram-negative sepsis remains challenging. Polymyxin B (PMB) is well suited for sepsis therapy due to the endotoxin affinity and antibacterial activity. However, the dose-limiting toxicity has limited its systemic use in sepsis patients. For safe systemic use of PMB, we have developed a nanoparticulate system, called D-TZP, which selectively reduces the toxicity to mammalian cells but retains the therapeutic activities of PMB. D-TZP consists of an iron-complexed tannic acid nanocapsule containing a vitamin D core, coated with PMB and a chitosan derivative that controls the interaction of PMB with endotoxin, bacteria, and host cells. D-TZP attenuated the membrane toxicity associated with PMB but retained the ability of PMB to inactivate endotoxin and kill Gram-negative bacteria. Upon intravenous injection, D-TZP protected animals from pre-established endotoxemia and polymicrobial sepsis, showing no systemic toxicities inherent to PMB. These results support D-TZP as a safe and effective systemic intervention of sepsis.

Recent advances in nanomedicine for sepsis treatment.

Sepsis and septic shock are life-threating conditions, which form a continuum of the body's response to overwhelming infection. The current treatment consists of fluid and metabolic resuscitation, hemodynamic and end-organ support, and timely initiation of antibiotics. However, these measures may be ineffective and the sepsis-related mortality toll remains substantial; therefore, an urgent need exists for new therapies. Recently, several nanoparticle (NP) systems have shown excellent protective effects against sepsis in preclinical models, suggesting a potential utility in the management of sepsis and septic shock. These NPs serve as antibacterial agents, provide platforms to immobilize endotoxin adsorbents, interact with inflammatory cells to restore homeostasis and detect biomarkers of sepsis for timely diagnosis. This review discusses the recent developments in NP-based approaches for the treatment of sepsis.

Succinylated chitosan derivative has local protective effects on intestinal inflammation.

We have previously reported on the anti-inflammatory effects of a water-soluble chitosan derivative, zwitterionic chitosan (ZWC). In the present study, we hypothesized that orally-administered ZWC would provide local anti-inflammatory effects in the intestinal lumen. ZWC indeed showed anti-inflammatory effects in various in-vitro models including peritoneal macrophages, engineered THP1 monocytes, and Caco-2 cells. In Caco-2 cells, ZWC applied before the lipopolysaccharide (LPS) challenge was more effective than when it was applied after it in preventing LPS-induced cell damage. When administered to mice via drinking water as a prophylactic measure, ZWC protected the animals from 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis, helping them to recover the body weight, restore the gross and histological appearance of the colon, and generate FoxP3+ T cells. In contrast, orally-administered ZWC did not protect the animals from LPS-induced systemic inflammation. These results indicate that orally-administered ZWC reaches the colon with minimal absorption through the upper gastrointestinal tract and provides a local anti-inflammatory effect.

Zwitterionic chitosan for the systemic treatment of sepsis.

Severe sepsis and septic shock are life-threatening conditions, with Gram-negative organisms responsible for most sepsis mortality. Systemic administration of compounds that block the action of lipopolysaccharide (LPS), a constituent of the Gram-negative outer cell membrane, is hampered by their hydrophobicity and cationic charge, the very properties responsible for their interactions with LPS. We hypothesize that a chitosan derivative zwitterionic chitosan (ZWC), previously shown to suppress the production of pro-inflammatory cellular mediators in LPS-challenged macrophages, will have protective effects in an animal model of sepsis induced by systemic injection of LPS. In this study, we evaluate whether ZWC attenuates the fatal effect of LPS in C57BL/6 mice and investigate the mechanism by which ZWC counteracts the LPS effect using a PMJ2-PC peritoneal macrophage cell line. Unlike its parent compound with low water solubility, intraperitoneally administered ZWC is readily absorbed with no local residue or adverse tissue reaction at the injection site. Whether administered at or prior to the LPS challenge, ZWC more than doubles the animals' median survival time. ZWC appears to protect the LPS-challenged organisms by forming a complex with LPS and thus attenuating pro-inflammatory signaling pathways. These findings suggest that ZWC have utility as a systemic anti-LPS agent.

Mannitol-guided delivery of Ciprofloxacin in artificial cystic fibrosis mucus model.

Abnormal airway mucus presents a significant challenge for inhalational drug delivery. Recognizing the thick and tenacious airway mucus seen in the cystic fibrosis (CF) patients as a critical barrier to effective drug delivery, both into the mucus layer itself as well as across that layer to the underlying airway epithelium, we hypothesize that mannitol or NaCl can form inhalable drug carriers, improve drug penetration into the mucus, and ultimately enhance the drug's therapeutic effect. The objective of this study is to test whether mannitol and NaCl particles, as inhalable drug carriers, improve drug delivery into and enhance a drug's activity within a mucus-like material. Microparticles containing Ciprofloxacin (Cipro), an active ingredient, and either mannitol or NaCl were produced by spray-drying. Cipro encapsulated in mannitol particles (Cipro-mannitol) was significantly more effective at killing Pseudomonas aeruginosa (P. aeruginosa) grown in artificial mucus (AM) than Cipro encapsulated in either NaCl particles (Cipro-NaCl) or in hydrophobic particles consisting of dipalmitoylphosphatidylcholine (DPPC), albumin, and lactose (Cipro-DAL). The relatively high antibacterial effectiveness of Cipro-mannitol was not due to the effect of mannitol on bacteria or on Cipro. Rather, the unique performance of the mannitol-based particles in AM is attributable to its ability to increase local water content in the AM and enhance drug penetration into it. Mannitol is a promising excipient for inhalable microparticles that facilitate the drug delivery into the CF mucus.

Challenges and advances in the development of inhalable drug formulations for cystic fibrosis lung disease.

INTRODUCTION: Cystic fibrosis (CF) is a multisystem genetic disorder, which usually results in significant respiratory dysfunction. At present there is no cure for CF, but advances in pharmacotherapy have gradually increased the life expectancy of CF patients. As many drugs used in the therapy of CF are delivered by inhalation, the demand for effective and convenient inhalational CF drug formulations will grow as CF patients live longer. Knowledge of the current limitations in inhalational CF drug delivery is critical in identifying new opportunities and designing rational delivery strategies. AREAS COVERED: This review discusses current and emerging therapeutic agents for CF therapy, selected physiological challenges to effective inhalational medication delivery, and various approaches to overcoming these challenges. The reader will find an integrated view of the known inhalational drug delivery challenges and the rationales for recent investigational inhalational drug formulations. EXPERT OPINION: An ideal drug/gene delivery system to CF airways should overcome the tenacious sputum, which presents physical, chemical and biological barriers to effective transport of therapeutic agents to the targets and various cellular challenges.

Inhalable antibiotic delivery using a dry powder co-delivering recombinant deoxyribonuclease and ciprofloxacin for treatment of cystic fibrosis.

PURPOSE: To achieve efficient antibiotic delivery to the cystic fibrosis (CF) airway using a single inhalable powder co-encapsulating a mucolytic and an antibiotic. METHODS: Inhalable dry powders containing deoxyribonuclease and/or ciprofloxacin (DNase, Cipro, and DNase/Cipro powders) were produced by spray-drying with dipalmitylphosphatidylcholine, albumin, and lactose as excipients, and their antibacterial effects were evaluated using the artificial sputum model. RESULTS: All powders showed mass median aerodynamic diameters below 5 microm. Both drugs were loaded in the dry powders without loss in quantity and activity. Dry powders containing DNase significantly decreased the storage modulus of the artificial sputum medium in less than 30 min. When applied to artificial sputum laden with Pseudomonas aeruginosa, Cipro/DNase powder showed better antibacterial activity than Cipro powder. The higher activity of the Cipro/DNase powder is attributable to the mucolytic activity of DNase, which promotes penetration of the dry powder into the artificial sputum and efficient dissolution and diffusion of ciprofloxacin. CONCLUSIONS: Inhalational delivery of antibiotics to the CF airway can be optimized when the sputum barrier is concomitantly addressed. Co-delivery of antibiotics and DNase using an inhalable particle system may be a promising strategy for local antipseudomonal therapy in the CF airway.

Development of highly porous large PLGA microparticles for pulmonary drug delivery.

We report a new process of making highly-porous large polymeric microparticles for local drug delivery to the lungs by inhalation. Poly(lactic-co-glycolic acid) (PLGA) microparticles (average diameter, 10-20 microm) were made by the double-emulsion method. To impart favorable aerodynamic properties, an effervescent salt ammonium bicarbonate (ABC) was included in the internal aqueous phase. ABC produced highly-porous structures in the PLGA particles as it escaped as ammonia and carbon dioxide. The fine-particle fraction (FPF) of the microparticles increased as a function of the ratio of ABC to PLGA. Microparticles prepared with 7.5%w/w (ABC/PLGA) had a mass median aerodynamic diameter (MMAD) of 4.0 +/- 1.2 microm and FPF of 32.0 +/- 9.1% when tested with Anderson Cascade Impactor (ACI) and Rotahaler. The highly-porous large particles deposited at the ACI stages corresponding to the trachea and below. The highly-porous large particles avoided phagocytosis by macrophages, while non-porous small particles were quickly taken up by the macrophages. Unlike other encapsulation methods which employ osmogens or extractable porogens, this method could encapsulate lysozyme and doxorubicin.HCl, with high encapsulation efficiency ( approximately 100% for both lysozyme and doxorubicin), in the PLGA microparticles characterized by desirable MMAD (4.5 +/- 0.6 microm lysozyme; 4.6 +/- 0.4 microm doxorubicin) and FPF (29.1 +/- 12.2% lysozyme; 33.8+/-3.6% doxorubicin). Fifty-two percent of encapsulated doxorubicin was released over 4 days from the highly-porous microparticles. This method is an efficient way of making polymeric microparticles for sustained local drug delivery by inhalation.

Microparticles for inhalational delivery of antipseudomonal antibiotics.

Chronic pseudomonal bronchopulmonary infections in cystic fibrosis patients are frequently controlled with inhaled antibiotics. Dry-powder inhalable antibiotics are an attractive alternative to nebulized medications. We produced and evaluated microparticles composed of dipalmitoylphosphatidylcholine, albumin, and lactose as a model system for intrapulmonary delivery of ceftazidime, ciprofloxacin, and several combinations of the two, none of which is presently available for inhalation. Microparticles containing one or both antibiotics were prepared by spray-drying. Their Anderson cascade impactor deposition profiles showed 10-30% fine particle fractions of the nominal dose. Microparticles containing varying amounts of each antibiotic showed statistically different deposition profiles. Aerodynamics and deposition of microparticles co-encapsulating both antibiotics were similar to those of single-drug microparticles with the same proportion of ciprofloxacin alone. The antipseudomonal activities of microparticles co-encapsulating half of the 50% effective concentration (EC(50)) of both ceftazidime and ciprofloxacin (5 mg of particles containing 5% ceftazidime and 10% ciprofloxacin) were at least additive compared to particles containing the EC(50) of each antibiotic separately (5 mg of particles containing 10% ceftazidime or 5 mg of particles containing 20% ciprofloxacin). Co-encapsulation of the antibiotics in microparticles ensures co-deposition at desired ratios, improves the particles' aerodynamics and fine particle fraction, as compared to microparticles with equivalent amounts of ceftazidime alone, and achieves additive antipseudomonal activity.