Antimicrobial Composition Using Weak Acid Buffers for Skin pH Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Antimicrobial compositions containing benzoic acid analogs exhibit diminished residual activity on the skin due to the skin's natural pH increase, which compromises their effectiveness over time.
Innovation Solution
Incorporating a combination of weak organic acid buffers with pKa values between 3.2 and 4.9 and an antimicrobial copper ion salt, such as copper gluconate, along with glycine to maintain a lower skin pH and enhance buffering capacity, thereby prolonging the antimicrobial activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If benzoic acid analogs are applied to skin for antimicrobial activity, then immediate antimicrobial effect is achieved, but residual activity diminishes over time due to skin pH increase
Solution Approach 1:
The patent introduces weak organic acid buffers (lactic acid, adipic acid, nicotinic acid, acetic acid) as intermediary substances that mediate between the skin's natural pH tendency and the antimicrobial composition's pH requirements. These buffers act as a pH-stabilizing layer that prevents the skin from returning to its natural pH, thereby maintaining the acidic environment needed for sustained antimicrobial activity of benzoic acid analogs.
Solution Approach 2:
The patent changes the pH parameter of the skin surface by applying a composition with pH 3.2-4.9 containing multiple weak organic acid buffers. This parameter change is maintained over time through the buffering action of lactic acid (pKa 3.86), adipic acid (pKa 4.43), nicotinic acid (pKa 4.82), and acetic acid (pKa 4.76), which collectively resist pH increase and sustain the acidic conditions required for prolonged antimicrobial efficacy.
2Reliability
If copper ion salt is added to enhance antimicrobial activity, then antimicrobial efficacy is improved, but precipitation occurs with weak acid buffers
Solution Approach 1:
The patent controls the pH parameter within a specific range (3.2-4.9) and uses multiple weak organic acid buffers with different pKa values to maintain this range. This parameter control prevents copper ion precipitation by keeping the environment sufficiently acidic to maintain copper solubility while still providing the desired antimicrobial activity.
Solution Approach 2:
The patent creates a composite buffering system using four different weak organic acids (lactic acid, adipic acid, nicotinic acid, and acetic acid) with distinct pKa values. This composite buffer system provides broader and more stable pH control compared to a single buffer, ensuring both formulation stability and sustained antimicrobial activity of copper ions over time.
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 solution effectively prolongs the antimicrobial activity of benzoic acid analogs on the skin by maintaining a stable acidic pH, preventing the natural skin pH increase and ensuring sustained efficacy.
Implementation Method 1
Incorporating a combination of weak organic acid buffers with pKa values between 3.2 and 4.9 and an antimicrobial copper ion salt, such as copper gluconate, along with glycine to maintain a lower skin pH and enhance buffering capacity
Implementation Method 2
an antimicrobial copper ion salt in a weight percent of copper of between 0.0025%-0.2% of the composition
Data Source
AI summary
Various embodiments provide an antimicrobial composition comprising: a safe and effective amount of benzoic acid analog or analogs; a safe and effective amount of a buffer system of weak organic acids buffer with the negative log of the acid dissociation constant, pKa, between about 3.2 and 4.9; and a dermatologically acceptable carrier for the benzoic acid analogs and weak organic acid buffers, wherein the antimicrobial composition has a pH from about 3.2 to 4.9. In some embodiments, the antimicrobial composition comprises a safe and effective amount of an antimicrobial metal ion salt, a preferred salt being copper gluconate, at a level and pH that does not precipitate with the weak acid buffers.