Background and objective: Metered-dose inhalers (MDIs) remain
fundamental to the management of asthma and chronic obstructive pulmonary
disease (COPD) due to their portability, dosing accuracy, patient convenience,
and cost-effectiveness. Despite advances in inhalation therapy encompassing
formulation science, device engineering, and regulatory frameworks, MDIs
continue to occupy a central role in clinical practice and pharmaceutical
development.
Objectives: This chapter provides a comprehensive and
critical overview of contemporary MDI technologies, including conventional
pressurised MDIs, breath-actuated devices, and non-pressurised soft mist
inhalers (SMIs). Key aspects addressed include operating principles,
formulation and propellant considerations, device design, aerosol performance,
and dose delivery characteristics. The chapter further evaluates recent
technological advancements, clinical benefits, and persistent challenges,
including patient adherence, environmental sustainability, and dose
reproducibility. Industrial and regulatory perspectives influencing inhalation
product development and commercialisation are also discussed.
Methodology: This chapter is based on a structured critical
review of current scientific, technical, and industrial literature related to
MDI development and performance. Peer-reviewed research articles, review
papers, pharmacopeial standards, and regulatory guidance documents were
systematically analysed to capture advances in formulation science, device
technology, regulatory expectations, and sustainability initiatives. Authoritative
guidance from regulatory agencies such as the U.S. Food and Drug Administration
(FDA), the European Medicines Agency (EMA), and the International Council for
Harmonisation (ICH) was examined to contextualise development and compliance
requirements. Particular emphasis was placed on device engineering, aerosol
generation and characterisation, formulation device interactions, and the
application of quality-by-design (QbD) principles across product development,
manufacturing, and lifecycle management.
Conclusions: MDIs remain indispensable in the long-term
treatment of asthma and COPD; however, their continued clinical relevance
depends on effectively addressing challenges related to patient misuse,
adherence, and the environmental impact of hydrofluoroalkane (HFA) propellants.
Future progress in MDI technology will require an integrated, multidisciplinary
approach that combines advances in formulation science, environmentally
sustainable propellant alternatives, and user-centred device design. From a regulatory
and quality standpoint, critical performance attributes such as aerodynamic
particle size distribution, emitted dose uniformity, extractables and
leachables assessment, and robust in vitro-in vivo correlations will remain
essential for ensuring product safety and therapeutic efficacy. Alignment with
evolving regulatory expectations, supported by risk-based design strategies and
QbD-driven development, will be pivotal in advancing next-generation MDIs that
are clinically effective, patient-friendly, and environmentally responsible.
Emerging trends and future research directions are highlighted to provide a
forward-looking framework for researchers, clinicians, and industry
stakeholders in inhalation drug delivery.
Author(s) Details
Chinna Reddy Palem
Formulation R&D, Asphar Research Labs Pvt. Ltd., IDA, Balanagar,
Hyderabad-500037; Telangana, India.
Sridhar Gumudevelli
Product Development, Ascent Pharmaceuticals Inc., 400S. Technology Drive,
Central Islip, NY 11722, USA.
Please see the book here :- https://doi.org/10.9734/bpi/psnid/v9/6886
No comments:
Post a Comment