Investigation of Aerosol Formation During Benzaldehyde Photolysis

The kinetics of photolysis and photonucleation of benzaldehyde (BA) vapor in the air and in an inert gas is investigated, along with the physical and chemical characteristics of the resulting aerosol particles. Short-lived free radicals that accompany the BA photonucleation process were identified by means of spin trapping. Numerical simulation of BA photonucleation, combined with the proposed chemical mechanism, allowed us to calculate the rate of generation of initial particles and to estimate the aerosol quantum yield.

Aerosol Inhalation Delivery of Triazavirin in Mice: Outlooks for Advanced Therapy Against Novel Viral Infections

Under pandemic-caused emergency, evaluation of the potential of existing antiviral drugs for the treatment of COVID-19 is relevant. Triazavirin, an antiviral drug developed in Russia for per-oral administration, is involved in clinical trials against SARS-CoV-2 coronavirus. This virus has affinity to epithelial cells in respiratory tract, so drug delivery directly in lungs may enhance therapeutic effect and reduce side effects for stomach, liver, kidneys. We elaborated ultrasonic method of triazavirin aerosol generation and investigated the inhalation delivery of this drug in mice. Mean particle size and number concentration of aerosol used in inhalation experiments are 560 nm and 4 × 105 cm-3, respectively. Aerosol mass concentration is 1.6 × 10-4 mg/cm3. Inhalation for 20 min in a nose-only chamber resulted in 2 mg/kg body delivered dose and 2.6 μg/mL triazavirin concentration in blood plasma. Elimination rate constant determined in aerosol administration experiments was ke = 0.077 min-1, which agrees with the value measured after intravenous delivery, but per-oral administration resulted in considerably lower apparent elimination rate constant of pseudo-first order, probably due to non-linear dependence of absorption rate on triazavirin concentration in gastrointestinal tract. The bioavailability of triazavirin aerosol is found to be 85%, which is about four times higher than for per-oral administration.

Aerosol inhalation delivery of cefazolin in mice: Pharmacokinetic measurements and antibacterial effect

Aerosol inhalation delivery of cefazolin, a broad-spectrum first-generation cephalosporin antibiotic, was investigated. Inhalation system based on ultrasonic nebulizer was developed for the generation of dry cefazolin aerosol within mean particle diameter range 0.5-3.0 μm and mass concentration 0.01-3 μg/cm³. Pharmacokinetic measurements were carried out for the aerosolized form of cefazolin delivered in mice using nose-only chamber. Cefazolin concentrations in blood serum and in the lungs of mice were measured as a function of time by means of high performance liquid chromatography. Body-delivered dose depending on particle size, concentration and inhalation time as well as other pharmacokinetic parameters were determined. The antibacterial effect of aerosolized cefazolin was assessed through the aerosol inhalation treatment of mice infected with Klebsiella pneumoniae. Survival rate for infected mice after the treatment with cefazolin aerosol demonstrated high antibacterial efficiency of the inhalation delivery of cefazolin in comparison with intraperitoneal delivery.

Aerosol Inhalation Delivery of Ceftriaxone in Mice: Generation Procedure, Pharmacokinetics, and Therapeutic Outcome

Aerosol inhalation delivery of ceftriaxone in mice was investigated. An ultrasonic nebulizer within the ranges of mean particle diameter 0.5–1.5 μm and mass concentration 0.01–0.6 μg/cm³ was used in inhalation experiments. Pharmacokinetic measurements were carried out using a nose-only chamber. Ceftriaxone concentration in blood serum and its mass in the lungs of mice were measured as a function of time using high-performance liquid chromatography. The body-delivered dose was within the range 3–5 mg/kg. The antibacterial effect of aerosolized ceftriaxone was investigated for mice infected with Klebsiella pneumoniae 82 and Staphylococcus aureus ATCC 25 953. The survival rate for infected mice after the treatment with ceftriaxone aerosol revealed the high antibacterial efficiency of this kind of treatment.

Studies of the Specific Activity of Aerosolized Isoniazid against Tuberculosis in a Mouse Model

The aerosol inhalation delivery of isoniazid in mice was investigated, and the specific activity of the aerosol form of isoniazid was studied with the mouse model of tuberculosis infection, the M. tuberculosis H37Rv strain. Aerosol delivery was performed using a laminar-flow horizontal nucleation chamber. The inhalation dose was measured in real-time mode using a diffusion aerosol spectrometer. The mean particle diameter was 0.6 ± 0.03 μm, and the inhalation dose was 5–9 mg/kg. Pharmacokinetic measurements were carried out in nose-only and whole-body chambers. Isoniazid concentration in blood serum and its mass in the lungs were measured as a function of time using high-performance liquid chromatography. Studies of the specific activity of aerosolized isoniazid reveal that treatment with the aerosol lead to the complete recovery of the experimental tuberculosis infection as early as after 28 days after the start of inhalation treatment, while in the animals from the group receiving isoniazid per-orally, sole revivable tuberculosis mycobacteria were detected. Histologic examinations show that only a few macrophagal (nonspecific) granulomas without mycobacteria were detected in the spleen after per-oral and aerosol treatment, the number of granulomas on the 28th day being three times smaller in the latter case. The results show that the developed technique of isoniazid aerosol inhalation may have clinical potential.