Modeling breath-enhanced jet nebulizers to estimate pulmonary drug deposition

A path forward in the development of new aerosol drug delivery devices for pediatrics

Inhaled medications are widely accepted as being the optimal route for treating pediatric respiratory diseases, a leading cause of hospitalization and death. Despite jet nebulizers being the preferred inhalation device for neonates and infants, current devices face performance issues with most of the drug never reaching the target lung location. Previous work has aimed to improve pulmonary drug deposition, yet nebulizer efficiency remains low. The development of an inhalant therapy that is efficacious and safe for pediatrics depends on a well-designed delivery system and formulation. To accomplish this, the field needs to rethink the current practice of basing pediatric treatments on adult studies. The rapidly evolving pediatric patient (i.e. neonates to eighteen) needs to be considered because they are different from adults with respect to airway anatomy, breathing patterns, and adherence. Previous research approaches to improve deposition efficiency have been limited due to the complexity of combining physics, which drives aerosol transport and deposition, and biology, especially within the area of pediatrics. To address these critical knowledge gaps, we need a better understanding of how patient age and disease state affect deposition of aerosolized drugs. The complexity of the multiscale respiratory system makes scientific investigation very challenging. The authors have simplified the complex problem into five components with these three areas as ones to address first: how the aerosol is (i) generated in a medical device, (ii) delivered to the patient, and (iii) deposited inside the lung. In this review, we discuss the technological advances and innovations made from experiments, simulations, and predictive models in each of these areas. In addition, we discuss the impact on patient treatment efficacy and recommend a clinical direction, with a focus on pediatrics. In each area, a series of research questions are posed and steps for future research to improve efficacy in aerosol drug delivery are outlined.

Clinical experimentation with aerosol antibiotics: current and future methods of administration

Currently almost all antibiotics are administered by the intravenous route. Since several systems and situations require more efficient methods of administration, investigation and experimentation in drug design has produced local treatment modalities. Administration of antibiotics in aerosol form is one of the treatment methods of increasing interest. As the field of drug nanotechnology grows, new molecules have been produced and combined with aerosol production systems. In the current review, we discuss the efficiency of aerosol antibiotic studies along with aerosol production systems. The different parts of the aerosol antibiotic methodology are presented. Additionally, information regarding the drug molecules used is presented and future applications of this method are discussed.

Establishing the optimal nebulization system for paclitaxel, docetaxel, cisplatin, carboplatin and gemcitabine: back to drawing the residual cup

BACKGROUND

Chemotherapy drugs have still the major disadvantage of non-specific cytotoxic effects. Although, new drugs targeting the genome of the tumor are already in the market, doublet chemotherapy regimens still remain the cornerstone of lung cancer treatment. Novel modalities of administration are under investigation such as; aerosol, intratumoral and intravascular.

MATERIALS AND METHODS

In the present study five chemotherapy drugs; paclitaxel, docetaxel, gemcitabine, carboplatin and cisplatin were nebulized with three different jet nebulizers (Maxineb(®), Sunmist(®), Invacare(®)) and six different residual cups at different concentrations. The purpose of the study was to identify the "ideal" combination of nebulizer-residual cup design-drug-drug loading for a future concept of aerosol chemotherapy in lung cancer patients. The Mastersizer(®) 2000 was used to evaluate the aerosol droplet mass median aerodynamic diameter.

RESULTS

The drug, nebulizer and residual cup design greatly influences the producing droplet size (p<0.005, in each case). However; the design of the residual cup is the most important factor affecting the produced droplet size (F=834.6, p<0.001). The drug loading plays a vital role in the production of the desired droplet size (F=10.42, p<0.001). The smallest droplet size was produced at 8 ml loading (1.26 μm), while it remained the same at 2, 4 and 6 mls of drug loading.

CONCLUSION

The ideal nebulizer would be Maxineb(®), with a large residual cup (10 ml maximum loading capacity) and 8 mls loading and the drug with efficient pulmonary deposition would be docetaxel.