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Boric Acid, a Lewis Acid With Unique and Unusual Properties: Formulation Implications
Antonio Lopalco1, Angela A Lopedota1, Valentino Laquintana1
1Department of Pharmacy - Drug Sciences, Università Degli Studi di Bari Aldo Moro, Bari 70125, Italy.
Journal of Pharmaceutical Sciences
|May 1, 2020
Summary
Boric acid serves diverse pharmaceutical roles, acting as an excipient and buffer. While generally safe at low doses, high exposure can lead to toxicity, particularly in children.
Area of Science:
- Pharmaceutical Science
- Chemistry
Background:
- Boric acid is a Lewis acid with a pKa of 8.92-9.24, influenced by concentration, temperature, and ionic strength.
- It exhibits reversible reactions with alcohols, carboxylic acids, thiols, and amines, forming adducts with lower pKa values.
- Boric acid's properties allow it to stabilize some substances while catalyzing the degradation of others.
Purpose of the Study:
- To review the multifaceted applications of boric acid in pharmaceutical formulations.
- To elucidate its chemical properties and reactivity relevant to drug delivery.
- To assess its safety profile across various administration routes and dosages.
Main Methods:
- Literature review of boric acid's chemical properties.
- Analysis of its use as an excipient, buffer, and active ingredient in pharmaceutical products.
- Evaluation of toxicological data from human and animal studies.
Main Results:
- Boric acid functions as a buffer, antibacterial, and antifungal agent in topical and ophthalmic preparations.
- It is used as an excipient in pharmaceutical formulations, with reactivity dependent on pH and concentration.
- While safe at low doses, high systemic exposure carries risks, including toxicity in children and reproductive effects in animals.
Conclusions:
- Boric acid is a versatile pharmaceutical ingredient with established uses in various formulations.
- Its chemical reactivity and buffering capacity are key to its functionality.
- Careful consideration of dosage and exposure is crucial due to potential toxicity.
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