Directly Compressible PVA-MCC Co-mixture for Tablet Hardness
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Solution Overview
Problem
Polyvinyl alcohols (PVAs) used in pharmaceutical formulations are not directly compressible, requiring complex granulation processes and high proportions of binders, which are time-consuming and costly, and often result in tablets with unsatisfactory hardness and friability, making them difficult to handle in pharmaceutical practice.
Innovation Solution
A directly compressible co-mixture of fine-grained polyvinyl alcohols (PVAs) and fine-grained microcrystalline celluloses (MCCs) is developed, with specific particle size ranges and ratios, allowing for the production of tablets with improved hardness and reduced friability, eliminating the need for granulation steps and using lower pressing forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If polyvinyl alcohols are used in pharmaceutical formulations, then extended release of active compound is achieved, but the tablets cannot be directly compressed and require complex granulation processes
Solution Approach 1:
The patent combines polyvinyl alcohol with microcrystalline cellulose to create a composite material that exhibits both extended release properties and direct compressibility. The microcrystalline cellulose acts as a compressible matrix that allows tablet formation without granulation, while the polyvinyl alcohol provides the extended release mechanism through gel formation and diffusion control.
Solution Approach 2:
The patent modifies the physical parameters of polyvinyl alcohol by controlling its degree of polymerisation (500-5000) and degree of hydrolysis (85-99%), and by using specific particle size ranges (50-250 μm). These parameter changes enable the material to achieve both extended release functionality and direct compressibility, eliminating the need for complex granulation processes.
2Ease of manufacture
If polyvinyl alcohols are tableted directly by pressure, then simplified production is achieved, but only under particular conditions and with high proportions of binders
Solution Approach 1:
The patent specifies particular parameter ranges for polyvinyl alcohol (degree of polymerisation 500-5000, degree of hydrolysis 85-99%, particle size 50-250 μm) that enable direct compression with minimal binders. These controlled parameters allow the material to self-compress effectively, reducing binder requirements from high proportions to just 1-5% of the total composition.
Solution Approach 2:
The patent uses microcrystalline cellulose as a disposable compressible matrix that provides the necessary binding and compression properties temporarily during tablet formation, then dissolves or erodes to release the active compound. This eliminates the need for permanent, high-proportion binder systems.
3Strength
If wet granulation is used to produce tablets with polyvinyl alcohol, then tablet hardness is improved, but high energy input is required for solvent removal
Solution Approach 1:
The patent extracts the granulation step entirely from the manufacturing process by using materials that are directly compressible. By removing the wet granulation process, the subsequent high-energy solvent removal step becomes unnecessary, as no solvent is introduced in the first place.
Solution Approach 2:
The polyvinyl alcohol-microcrystalline cellulose composition is self-sufficient for tablet formation, providing both the structural matrix and compression properties needed for tablet hardness without requiring external granulation aids or solvent-based processing.
4Ease of manufacture
If high proportions of binders are used to achieve direct tabletability, then manufacturing is simplified, but tablet friability increases and handling becomes difficult
Solution Approach 1:
The patent creates a composite where microcrystalline cellulose provides compressibility and structural integrity, while polyvinyl alcohol provides binding through hydrogen bonding and gel formation. This balanced composite achieves direct tabletability with minimal binders (1-5%) while maintaining low friability and high reliability for pharmaceutical handling.
Solution Approach 2:
By controlling the particle size of polyvinyl alcohol (50-250 μm) and its molecular characteristics (degree of polymerisation 500-5000, degree of hydrolysis 85-99%), the patent optimizes the material's compressibility and binding properties, enabling direct tablet formation with low binder content and satisfactory friability.
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 co-mixture enables the production of tablets with high tablet hardness and low friability, achieving extended release of active compounds over several hours with reduced ejection forces and energy input, simplifying the tablet development process and improving patient compliance.
Implementation Method 1
swelling and a gel forms from which the active compound is only released little by little by diffusion and slow erosion of the gel matrix
Implementation Method 2
the active compound is only released little by little by diffusion and slow erosion of the gel matrix
Implementation Method 3
directly compressible co-mixtures which comprise fine-grained polyvinyl alcohols (PVAs) and fine-grained microcrystalline celluloses (MCCs)
Data Source
AI summary
The present invention relates to a directly compressible composition for the production of tablets which comprise fine-grained polyvinyl alcohols (PVAs) and fine-grained microcrystalline celluloses (MCCs) in a co-mixture. The present invention also relates to the use of this mixture and to a process for the preparation thereof.