Investigation of Lung Pharmacokinetic of the Novel PDE4 Inhibitor CHF6001 in Preclinical Models: Evaluation of the PreciseInhale Technology.

BACKGROUND: Preclinical evaluation of new chemical entities (NCEs) designed to be administered by inhalation route requires lung administration to rodents, especially in the discovery phase. Different administration methods have been used until now, but more efforts are required to obtain controlled and reproducible lung deposition when only small amounts of neat powder material are available. METHODS: The PreciseInhale platform used in the present study enables well-controlled powder aerosol exposures with only small amounts of micronized neat material, providing data on inhalation pharmacokinetic (PK) of NCEs at a very early stage. The DustGun aerosol technology uses compressed air to generate a respirable aerosol from milligram-amounts of powder that is delivered to one animal at a time. The new methodology was used to investigate the inhalation PK and lung retention in the rat of the novel Chiesi PDE4 inhibitor CHF6001 in three exposure models of the PreciseInhale platform: nose-only, intratracheally intubated rat, and the isolated, ventilated, and perfused rat lung. Results were compared with data from two other pulmonary delivery systems commonly used in preclinical studies: liquid instillation and powder insufflation. RESULTS: Administration of micronized CHF6001 using the PreciseInhale system yielded lung exposures in the same range as the other tested devices, but the reproducibility in lung deposition was improved. The initial amount of CHF6001 in lungs at the first sampling time point was close to the predetermined target dose. Tracheal deposition with PreciseInhale (0.36 ± 0.22 µg) was significantly less than with other tested delivery systems: PennCentury (23.7 ± 3.2 µg) and Airjet (25.6 ± 7.2 µg). CONCLUSIONS: The PreciseInhale platform enabled the administration of CHF6001 powder with good accuracy and reproducibility, with low tracheal deposition. The new platform can be used at an early discovery stage to obtain inhalatory PK data for respirable aerosols of neat NCE powder without excipients and with minimal use of dry powder formulation work.

Water-Pipe Smoke Exposure-Induced Circulatory Disturbances in Mice, and the Influence of Betaine Supplementation Thereon.

BACKGROUND/AIMS: It has been shown, both experimentally and clinically, that water-pipe smoke (WPS) exposure adversely affects the cardiovascular system (CVS) through the generation of oxidative stress and inflammation. Betaine, a naturally occurring compound in common foods, has antioxidant and anti-inflammatory actions. However, its potential to mitigate the adverse effect of WPS on the CVS has never been reported before. This is the subject of this study in mice. METHODS: Mice were exposed daily for 30 min to either normal air (control), or to WPS for two consecutive weeks. Betaine was administered daily by gavage at a dose of 10mg/kg, 1h before either air or WPS exposure. RESULTS: Betaine mitigated the in vivo prothrombotic effect of WPS in pial arterioles and venules. Moreover, it reversed the WPS-induced decrease in circulating platelets. Likewise, betaine alleviated platelet aggregation in vitro, and the shortening of activated partial thromboplastin time and prothrombin time induced by WPS. Betaine reduced the increase of plasminogen activator inhibitor-1 and fibrinogen concentrations in plasma induced by WPS. Betaine also diminished the WPS-induced increase of plasma concentrations of interleukin 6 and tumor necrosis factor α, and attenuated the increase of lipid peroxidation and superoxide dismutase. Immunohistochemical analysis of the heart revealed an increase in the expression of inducible nitric oxide synthase and cytochrome C by cardiomyocytes of the WPS-exposed mice. These effects were averted by betaine. CONCLUSION: Our findings suggest that betaine treatment significantly mitigated WPS-induced hypercoagulability, and inflammation, as well as systemic and cardiac oxidative stress.

The in vitro and in vivo investigation of a novel small chamber dry powder inhalation delivery system for preclinical dosing to rats.

PURPOSE: This research describes a novel "minitower" dry powder delivery system for nose-only delivery of dry powder aerosols to spontaneously breathing rats. METHODS: The minitower system forces pressurized air through pre-filled capsules to deliver aerosolized drug to four nose ports; three of which house spontaneously breathing rats, with the fourth used as a control. Within each port are vent filters which capture drug that was not inhaled for further quantitation. These vent filters along with a novel control system referred to as the "artificial rat lung", allow for the theoretical amount of drug delivered and subsequently inhaled by each rat to be calculated. RESULTS: In vitro and in vivo studies have demonstrated this system's ability to deliver aerosolized drug to rats. The in vitro study showed that ∼30% of the starting dose reached the 4 ports and was available for inhalation. During in-vivo studies, rats inhaled ∼34% of the delivered dose. Of the estimated inhaled dose, 12-18% was detectable in the various tissue samples, with over 30% of the recovered dose found in the rat's lungs. CONCLUSION: Results show that this system is capable of reproducibly delivering drug to the lungs of spontaneously breathing rats. Advantages over current delivery methods include being amenable to the administration of multiple doses and using less (milligram) amount of starting material. In addition, this technique avoids anesthesia which is typically required for instillation or insufflation, and thus has the potential as an efficient and noninvasive aerosol delivery method for preclinical drug development.

Evaluation of toxicity to triclosan in rats following 28 days of exposure to aerosol inhalation.

The present study was conducted to investigate the potential subchronic toxicity of triclosan (TCS) in rats following 28 days of exposure by repeated inhalation. Four groups of six rats of each sex were exposed to TCS-containing aerosols by nose-only inhalation of 0, 0.04, 0.13, or 0.40 mg/L for 6 h/day, 5 days/week over a 28-day period. During the study period, clinical signs, mortality, body weight, food consumption, ophthalmoscopy, hematology, serum biochemistry, gross pathology, organ weights, and histopathology were examined. At 0.40 mg/L, rats of both sexes exhibited an increase in the incidence of postdosing salivation and a decrease in body weight. Histopathological alterations were found in the nasal septum and larynx. There were no treatment-related effects in rats of either sex at ⩽0.13 mg/L. Under the present experimental conditions, the target organs in rats were determined to be the nasal cavity and larynx. The no-observed-adverse-effect concentration in rats was determined to be 0.13 mg/L.