Spherical Granule Coating with Surfactant Suspension Stabilization
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Solution Overview
Problem
The production of spherical base granules containing hardly water-soluble drugs faces challenges with foaming and precipitation in layering liquids, leading to instability and reduced recovery ratios due to high shear forces, which complicates the coating process and results in agglomeration.
Innovation Solution
Incorporating micronized microcrystalline cellulose and polyoxyethylene hydrogenated castor oil as an emulsifier in the layering liquid improves suspension stability and suppresses foaming, allowing for stable coating without additional pulverization treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hardly water-soluble drug is added to a layering liquid, then the drug can be coated onto spherical core particles, but vigorous foaming occurs and suspension stability deteriorates
Solution Approach 1:
A nonionic surfactant is introduced as an intermediary substance to mediate between the hardly water-soluble drug particles and the aqueous layering liquid. The surfactant reduces surface tension and prevents foaming while maintaining drug particle suspension stability, enabling successful coating without the harmful foaming effect
Solution Approach 2:
The physical and chemical parameters of the layering liquid are modified by adjusting surfactant concentration, pH value, and ionic strength. These parameter changes optimize the suspension stability of hardly water-soluble drug particles and suppress foaming during the coating process
2Stability of the object's composition
If the layering liquid is stirred constantly to maintain suspension uniformity, then drug particles remain dispersed, but tube or spray nozzle clogging occurs due to precipitated/agglomerated particles
Solution Approach 1:
The nonionic surfactant acts as a protective intermediary that coats drug particles and prevents them from aggregating and precipitating. This eliminates the need for constant stirring while avoiding clogging of transfer tubes and spray nozzles
Solution Approach 2:
The surfactant is added to the layering liquid before drug particle addition, creating a pre-conditioned environment that prevents particle aggregation from the outset. This preliminary action eliminates subsequent precipitation and clogging problems
3Stability of the object's composition
If drug particle size is reduced to improve suspension stability and recovery ratio, then suspension uniformity improves, but an extra pulverization treatment step is required
Solution Approach 1:
Instead of changing particle size through pulverization, the chemical parameters of the layering liquid are modified by adding surfactants. This achieves improved suspension stability of larger drug particles without requiring additional size-reduction equipment or process steps
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 method enables the stable production of spherical base granules with high productivity and reduced agglomeration, maintaining suspension stability and improving the adhesion of drug particles to core particles, thus enhancing recovery ratios.
Implementation Method 1
from 0.01 to 1 % by mass of a polyoxyethylene hydrogenated castor oil as an emulsifier
Implementation Method 2
from 0.1 to 2 % by mass of micronized microcrystalline cellulose
Data Source
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Figure 5
AI summary
Spherical base granules comprising a hardly water-soluble drug and suited for film coating thereon are produced by layering spherical core particles with a drug-containing layering liquid comprising both micronized microcrystalline cellulose and an emulsifier therein and therefore having improved suspension stability.