Investigating the properties and performance of capsules used in dry powder inhalers

Parker, Siamac 2022. Investigating the properties and performance of capsules used in dry powder inhalers. PhD Thesis, Cardiff University. Item availability restricted.

	PDF - Accepted Post-Print Version Restricted to Repository staff only until 21 July 2025 due to copyright restrictions. Download (6MB)
	PDF (Cardiff University Electronic Publication Form) - Supplemental Material Restricted to Repository staff only Download (1MB)

Abstract

Dry Powder Inhalers (DPIs) deliver micronised drugs to the lungs to treat respiratory disease. Capsule-based DPIs utilise hard shell capsules, as a single-dose reservoir for a dry powder formulation, typically containing active pharmaceutical ingredients (APIs) and carrier excipients. The capsule material contains moisture, which can be problematic if it transfers to a formulation that is particularly hygroscopic or moisture-labile. Moisture content reduction can, however, result in changes to capsule material properties, e.g., brittleness. This project aims to better understand relationships between capsule moisture content and some key performance parameters for their use in a DPI, and evaluates the potential of new low moisture content capsules. Commercially available established (Quali-V®-I and Quali-G™) and innovative (‘Extra Dry’, XD) capsules were conditioned in humidity-controlled environments to manipulate capsule moisture content. Capsule dimensions, mechanical properties, and aerosolised delivery of an exemplar formulation from a capsule-loaded DPI were investigated using established and novel laboratory methods including optical coherence tomography (OCT), materials testing and cascade impaction using a Next Generation Impactor (NGI). Using compression testing to assess the ability of capsules to withstand a permanent deformation force showed that Quali-G™ XD capsules performed at least as well as Quali-G™ capsules, particularly when stored at low humidity, despite having significantly reduced moisture content. Extremely low moisture content Quali-V®-I XD capsules (0.57%w/w±0.14) maintained their puncture performance by producing comparable puncture profiles to Quali-V®-I capsules (4.36%w/w±0.11). The difference in fine particle faction (FPF) of a tiotropium bromide formulation emitted from a DPI loaded with Quali-V®-I XD (30.75%±1.92) and Quali-V®-I (29.6%±0.45) capsules was statistically insignificant (p>0.05). Innovative XD capsule products performed comparably to their more established counterparts in the examined performance parameters, indicating that capsule material adjustments can overcome concerns regarding material properties. This encourages further assessment of these products as a reservoir for a wide range of DPI formulations.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Pharmacy
Subjects:	Q Science > Q Science (General)
Date of First Compliant Deposit:	21 July 2022
Last Modified:	04 Mar 2023 02:16
URI:	https://orca.cardiff.ac.uk/id/eprint/151401

Actions (repository staff only)

Edit Item