Aliskiren Oral Tablet High Drug Loading Formulation
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Solution Overview
Problem
Aliskiren, a renin inhibitor, is difficult to formulate into reliable and robust oral tablet forms due to its needle-shaped crystal habit, poor compression behavior, high hygroscopicity, and variable drug substance properties, leading to processability issues and stability concerns.
Innovation Solution
Development of a solid oral dosage form with a high active ingredient loading of aliskiren or its hemi-fumarate salt, combined with suitable excipients like microcrystalline cellulose, crosslinked PVP, and colloidal silicon dioxide, using a wet granulation process with organic solvents to achieve stable and robust tablets with improved flow and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If aliskiren is formulated with high drug loading to reduce tablet size, then the physical dimensions of the dosage form are reduced, but the compressibility and interparticulate bonding are severely compromised due to the needle-shaped crystal habit and strong elastic component
Solution Approach 1:
The patent introduces specific excipients acting as intermediaries between aliskiren crystals: microcrystalline cellulose provides a matrix for particle bonding, croscarmellose sodium acts as a superdisintegrant that facilitates controlled breakdown, and magnesium stearate serves as a lubricant that prevents excessive friction. These intermediaries enable sufficient compressibility and interparticulate bonding even at high drug loading levels (40-60% w/w) where direct compression would otherwise fail.
Solution Approach 2:
The patent modifies physical parameters of the formulation system by controlling particle size distribution (aliskiren particles reduced to specific ranges), adjusting moisture content to prevent hygroscopic degradation, and optimizing compression force parameters. These parameter changes enable the needle-shaped crystals to be compressed into robust tablets without excessive elastic recovery or interparticulate bond failure.
2Ease of manufacture
If aliskiren is processed through direct compression to simplify manufacturing, then the process complexity is reduced, but the flowability and dose uniformity are severely compromised due to poor flow properties and variable drug substance quality
Solution Approach 1:
The patent applies preliminary granulation processing to aliskiren powder before compression, converting the poor-flowing needle-shaped crystals into granules with improved flow characteristics. This preliminary action of granulation (using binders like PVP or HPMC) creates particles with better spherical morphology and size distribution, enabling subsequent direct compression to achieve uniform dosing without excessive process complexity.
Solution Approach 2:
The patent introduces glidants such as colloidal silicon dioxide as intermediary substances that coat the aliskiren particles and improve interparticle flow characteristics. This intermediary layer reduces friction and electrostatic charges on the needle-shaped crystals, enabling adequate flowability for direct compression while maintaining dose uniformity through consistent powder flow into die cavities.
3Ease of manufacture
If aliskiren is exposed to moisture during processing to improve granulation, then the granulation process is enhanced, but the drug substance undergoes polymorphism changes to amorphous state with inferior stability
Solution Approach 1:
The patent conducts granulation and processing operations in a controlled low-humidity environment or using organic solvent-based binders (such as ethanol or isopropanol solutions) instead of aqueous systems. This inert processing environment prevents moisture-induced polymorphic transformation of aliskiren from its stable crystalline form to the unstable amorphous state, while still enabling effective granulation through solvent evaporation and binder adhesion mechanisms.
Solution Approach 2:
The patent utilizes controlled phase transitions of organic solvents (evaporation from liquid to gas) to achieve granulation without water exposure. The solvent evaporation process provides the necessary drying and binding effects while maintaining aliskiren in its stable crystalline phase, avoiding the harmful polymorphic transition that occurs with moisture exposure.
4Volume of stationary object
If roller compaction is used to reduce bulk volume of aliskiren, then the bulk density is improved, but the pre-compression damage makes further compression into robust tablets extremely difficult
Solution Approach 1:
The patent performs preliminary size reduction and classification of aliskiren crystals before roller compaction to create a more uniform particle size distribution. This preliminary action prevents excessive fragmentation and crystal damage during compaction, preserving the mechanical integrity needed for subsequent tablet compression. The pre-classified material compacts more uniformly without excessive elastic recovery or particle breakdown.
Data Source
AI summary
The present invention relates to a solid oral dosage form comprising a therapeutically effective amount of aliskiren or a pharmaceutically acceptable salt thereof, and wherein the active ingredient is present in an amount of more than 46% by weight based on the total weight of the oral dosage form.