Freeze-Dried Ascorbic Acid Tablets via pH Control
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Solution Overview
Problem
Existing methods struggle to create stable, high-concentration freeze-dried compositions of acidic active ingredients like ascorbic acid, which are prone to dissociation and freezing-point lowering, leading to instability and poor mechanical strength in large-format applications.
Innovation Solution
Formulations containing ≥75% by weight of ascorbic acid and <15% by weight of polysaccharides, polyaminosaccharides, or synthetic polymers as skeleton-formers, with a pH adjusted to <7, to maintain the active ingredients in an undissociated form and enhance mechanical stability and solubility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high concentrations of acidic active ingredients (e.g., ascorbic acid) are used in freeze-dried compositions, then the active ingredient content and effectiveness are improved, but the compositions become unstable due to dissociation and freezing-point lowering
Solution Approach 1:
The patent adjusts the pH of the composition to a specific range (pH 2.0-4.0) before freeze-drying to suppress dissociation of acidic active ingredients. This parameter change maintains the active ingredients in their undissociated form, preventing freezing-point lowering and compositional instability while allowing high concentrations (≥75% by weight) to be successfully freeze-dried into stable compositions
Solution Approach 2:
The patent introduces pH-adjusting agents (acids or bases) as intermediaries to control the dissociation state of acidic active ingredients. These intermediaries regulate the pH environment during freeze-drying, enabling stable incorporation of high concentrations of active ingredients without the harmful effects of dissociation
2Quantity of substance
If high concentrations of acidic active ingredients are used, then the effectiveness is improved, but the mechanical strength of the freeze-dried tablets deteriorates
Solution Approach 1:
The patent creates a composite material system combining acidic active ingredients with pH-adjusting agents and freeze-drying excipients. This composite approach allows the active ingredients to be embedded in a matrix that provides mechanical strength while maintaining high active ingredient concentrations (≥75% by weight) through controlled pH and freeze-drying parameters
3Quantity of substance
If the concentration of active ingredients is increased, then the dosage efficiency is improved, but the solubility and dissolution rate may be affected
Solution Approach 1:
The freeze-drying process creates a porous structure in the tablets that facilitates rapid water penetration and active ingredient dissolution. This porous morphology, combined with pH optimization, ensures that even high-concentration formulations (≥75% active ingredient) dissolve quickly and completely upon contact with aqueous environments, maintaining high dissolution rates despite increased concentration
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 approach results in mechanically stable, rapidly soluble, and highly concentrated freeze-dried tablets with improved bioavailability and skin penetration, overcoming the limitations of previous methods in handling acidic active ingredients.
Implementation Method 1
the method of freeze-drying is known and widely used
Implementation Method 2
the substances are often subjected directly to freeze-drying
Implementation Method 3
which have a high degree of instability to thermal influences and those which are highly sensitive to light, moisture and/or oxidation
Data Source
AI summary
The invention relates to freeze-dried molded bodies containing ≥ 50 wt.% of one or more active ingredients and ≤ 15 wt.% of one or more scaffolding agents, excluding proteins, and optionally one or more excipients, each based on the total composition of the freeze-dried molded body, the 1 wt.% solution or suspension of which in water at 20 °C has a pH value < 7. The invention further relates to methods for producing these freeze-dried molded bodies, the combination of such freeze-dried molded bodies in kit-of-parts arrangements together with aqueous solutions, and the use of the freeze-dried molded bodies and the kit-of-parts combinations for pharmaceutical and cosmetic applications.