HPMC Capsule with CaCl2 for DPI Powder Retention
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Solution Overview
Problem
HPMC capsules used in Dry Powder Inhalers (DPI) with gelling agents exhibit interactions with dissolution media, leading to altered dissolution profiles and mechanical properties that are not desirable, and there is a need for capsules without gelling agents that maintain comparable powder retention and mechanical performance.
Innovation Solution
Incorporating a specific amount of CaCl2 into the shell material of HPMC capsules eliminates the need for gelling agents while enhancing powder retention and mechanical properties, such as puncture performance, by forming a capsule shell comprising HPMC and CaCl2 without any gelling agents or aids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If gelling agents are used in HPMC capsules for DPI applications, then mechanical properties are improved, but dissolution profiles are altered and powder retention is reduced
Solution Approach 1:
The invention removes gelling agents from the HPMC capsule formulation entirely, extracting the problematic component that causes dissolution profile alterations. The capsule shell is formulated using only HPMC and CaCl2, eliminating the need for gelling agents like carrageenan or gellan gum that interfere with dissolution media.
Solution Approach 2:
The invention changes the chemical composition parameters of the capsule shell by incorporating specific amounts of CaCl2 (3,000-9,000 ppm based on HPMC weight) to replace the functional role of gelling agents. This parameter change maintains mechanical integrity while preserving dissolution characteristics.
2Ease of manufacture
If gelling agents are used in HPMC capsules, then capsule formation is facilitated, but powder retention in DPI applications is reduced
Solution Approach 1:
The invention extracts and removes gelling agents from the formulation, eliminating the source of powder retention problems. By using only HPMC and CaCl2, the capsule shell no longer exhibits the powder adhesion characteristics associated with gelling agents.
Solution Approach 2:
The invention modifies the chemical composition by adding CaCl2 at specific concentrations (3,000-9,000 ppm) to achieve optimal powder retention without requiring gelling agents. This parameter change fundamentally alters the surface properties of the capsule shell.
3Stability of the object's composition
If gelling agents are used in HPMC capsules, then gelling ability is enhanced, but interaction with dissolution media occurs
Solution Approach 1:
The invention completely removes gelling agents from the capsule shell formulation, eliminating the source of harmful interactions with dissolution media. The capsule now consists only of HPMC and CaCl2, which do not exhibit the unwanted interactions.
Solution Approach 2:
The invention uses CaCl2 as an intermediary substance that provides the necessary structural support and gelling-like properties without the harmful interactions. CaCl2 acts as a mediator that maintains capsule integrity while being compatible with dissolution media.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The HPMC capsules with CaCl2 show improved powder retention and mechanical performance, comparable to or exceeding those with gelling agents, ensuring efficient operation in DPIs without the interference of gelling agents with dissolution media.
Implementation Method 1
Incorporating a specific amount of CaCl2 into the shell material of HPMC capsules eliminates the need for gelling agents while enhancing powder retention and mechanical properties, such as puncture performance, by forming a capsule shell comprising HPMC and CaCl2
Data Source
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AI summary
The invention discloses hydroxypropyl methylcellulose (HPMC) capsules containing a small amount of CaCl2, which show reduced powder retention when used in Dry Powder Inhalers (DPI), and a method for making them.