Review of the TAIFUN® Multidose Dry Powder Inhaler Technology

The future of dry powder inhaled therapy: Promising or Discouraging for systemic disorders?

Dry powder inhalation therapy has been shown to be an effective method for treating respiratory diseases like asthma, Chronic Obstructive Pulmonary Diseases and Cystic Fibrosis. It has also been widely accepted and used in clinical practices. Such success has led to great interest in inhaled therapy on treating systemic diseases in the past two decades. The current coronavirus (COVID-19) pandemic also has increased such interest and is triggering more potential applications of dry powder inhalation therapy in vaccines and antivirus drugs. Would the inhaled dry powder therapy on systemic disorders be as encouraging as expected? This paper reviews the marketed and in-development dry powder inhaler (DPI) products on the treatment of systemic diseases, their status in clinical trials, as well as the potential for COVID-19 treatment. The advancements and unmet problems on DPI systems are also summarized. With countless attempts behind and more challenges ahead, it is believed that the dry powder inhaled therapy for the treatment of systemic disorders still holds great potential and promise.

Dry powder inhalation: past, present and future

INTRODUCTION

Early dry powder inhalers (DPIs) were designed for low drug doses in asthma and COPD therapy. Nearly all concepts contained carrier-based formulations and lacked efficient dispersion principles. Therefore, particle engineering and powder processing are increasingly applied to achieve acceptable lung deposition with these poorly designed inhalers. Areas covered: The consequences of the choices made for early DPI development with respect of efficacy, production costs and safety and the tremendous amount of energy put into understanding and controlling the dispersion performance of adhesive mixtures are discussed. Also newly developed particle manufacturing and powder formulation processes are presented as well as the challenges, objectives, and new tools available for future DPI design. Expert opinion: Improved inhaler design is desired to make DPIs for future applications cost-effective and safe. With an increasing interest in high dose drug delivery, vaccination and systemic delivery via the lungs, innovative formulation technologies alone may not be sufficient. Safety is served by increasing patient adherence to the therapy, minimizing the use of unnecessary excipients and designing simple and self-intuitive inhalers, which give good feedback to the patient about the inhalation maneuver. For some applications, like vaccination and delivery of hygroscopic formulations, disposable inhalers may be preferred.

Pulmonary delivery of therapeutic compounds for treating CNS disorders

Delivering therapeutic compounds via the lungs presents potential advantages relative to other routes of administration. Depending on the compound and the disease state, these advantages may include: non-invasive medication delivery, ease of administration, higher bioavailability leading to dose sparing and lower systemic toxicity, potentially greater blood–brain barrier penetration and rapid pharmacodynamic effect. The practice of inhaling drugs has been around for centuries, including both medical and recreational usage. It is only more recently that formal clinical development programs have been undertaken specifically to use medication delivery via the lung to achieve systemic blood levels for the treatment of CNS disorders. At present, there are several CNS therapies being developed for pulmonary administration, with some of those programs at or near the marketing authorization stage. While there are still regulatory hurdles before these therapies can be put into practice, the success of these programs thus far demonstrates the scientific viability of inhalation therapies for treating CNS disorders.

Development of an inhalation chamber and a dry powder inhaler device for administration of pulmonary medication in animal model

CONTEXT

Pulmonary route of administration is becoming more popular for drug delivery in pulmonary tract and lungs for local and systemic actions.

OBJECTIVE

A dry powder inhaler (DPI) for delivery of dry powder and a nose-only inhalation chamber for small animals that can be used with nebuliser/DPI were designed.

MATERIALS AND METHODS

The inhalation chamber was made with a polypropylene-rectangular box and centrifuge tubes. DPI was made of a polypropylene tube. Micronized voriconazole and voriconazole solution were used for DPI and nebulizer, respectively, for both in vitro and in vivo studies.

RESULTS

In vitro drug deposition from nebulizer was found to be 11-26% w/w and that from DPI was 42 to 57% w/w depending on experimental set up. Uniform deposition across all the inhalation ports was observed irrespective of the methods. Respirable fraction (RF) varied from 34 to 73% in case of nebulizer and from 47 to 54% in case of DPI. In vivo deposition of voriconazole in lungs was found to be 80-130 µg/g of lung tissue in case of DPI and 40-68 µg/g of lung tissue in case of using nebulizer.

DISCUSSION

DPI designed was efficient in fluidizing powder bed and dispensing dry powder for inhalation. The inhalation chamber designed was efficient in uniformly distributing drug in various inhalation ports of the chamber.

CONCLUSIONS

The DPI and inhalation chamber designed can be successfully used for inhalation study with multiple animals especially mice.