Diltiazem HCl Multiparticulate Formulation for Sustained Release
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Solution Overview
Problem
Current formulations of diltiazem HCl require multiple daily administrations due to rapid absorption and significant first-pass metabolism, leading to variable bioavailability and inconvenience in maintaining therapeutic levels throughout the day.
Innovation Solution
Development of granules comprising an inner core of diltiazem HCl with a spherical layer and an external coating for sustained release, allowing for a single daily administration while maintaining optimal therapeutic levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional diltiazem HCl formulations are used, then rapid absorption and total absorption are achieved, but first-pass metabolism reduces bioavailability to around 40% and requires multiple daily administrations
Solution Approach 1:
The formulation is divided into multiple granules (500-1000 granules per capsule) with different release characteristics. Each granule contains diltiazem HCl core (500-710 μm) coated with controlled-release membrane, creating a population of particles that release drug at different rates, thereby maintaining stable plasma levels throughout the day and reducing first-pass metabolism impact.
Solution Approach 2:
The controlled-release coating system creates periodic drug release patterns where the coating membrane controls the rate at which diltiazem HCl is released from each granule. This periodic release mechanism ensures sustained therapeutic levels over 24 hours with single daily administration, overcoming the rapid absorption followed by quick elimination problem.
2Reliability
If multiple daily administrations are given, then therapeutic levels can be maintained, but patient convenience is reduced and compliance becomes difficult
Solution Approach 1:
The multiparticulate controlled-release formulation provides continuous drug release over 24 hours through the coordinated action of numerous granules with slightly different release profiles. This continuous release action eliminates the need for multiple daily dosing while maintaining stable therapeutic levels, significantly improving patient convenience and compliance.
3Quantity of substance
If high concentration of diltiazem HCl is used, then correct dosage is achieved, but volume for administration increases
Solution Approach 1:
The granule size parameters are optimized to 500-710 μm core diameter with final granule diameter of 700-900 μm, and the capsule contains 500-1000 granules. This parameter optimization allows high diltiazem HCl concentration (90% purity) while keeping the total volume suitable for single daily administration, balancing dosage accuracy with administration convenience.
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 multiparticulate formulation stabilizes gastrointestinal transit, ensures correct dosage with minimal volume, and provides sustained release of diltiazem HCl for 24 hours, achieving consistent therapeutic levels with a single daily dose.
Implementation Method 1
an external coating which is capable of providing a sustained release of diltiazem HCl
Implementation Method 2
a layer of diltiazem HCl spherically surrounding the core, applied to the core by spraying a suspension containing powdered diltiazem HCl
Data Source
AI summary
A multiparticulate formulation of diltiazem HCl is described which, in appropriate dosage and minimum volume, can be given as a single daily administration while guaranteeing, by means of appropriate sustained release, therapeutic levels of the drug throughout the course of the day. The formulation is characterised by microgranules having an extruded nucleus of diltiazem HCl surrounded by a layer of powdered diltiazem HCl, the whole coated with a sustained-released membrane based on ethyl cellulose and stearic acid.