Antioxidant Excipients


All substances in a pharmaceutical preparation that retard the oxidizing effects of the drug preparation are called antioxidants. Certain drugs that are easily oxidized can also undergo autoxidation after being formulated into injections, resulting in the deepening of the color of the drug solution, precipitation, reduction or disappearance of the efficacy of the drug, or even the production of toxic substances and other phenomena. Therefore, in order to prevent the oxidation of the drug and increase the stability of the drug, some suitable antioxidants can be added to the injection.

Mechanism of Antioxidant

Oxidation of a drug is the loss of electrons or loss of positively charged atoms, groups of atoms, on the structure of the drug molecule, or the gain of oxygen atoms or gain of negatively charged atoms, groups of atoms. In a redox reaction, the substance that loses electrons is the reducing agent, the electron giver, which is itself oxidized, and the substance that gains electrons is the oxidizing agent, the electron acceptor.

Based on the principle that compounds undergo oxidation reactions, as an effective antioxidant, the structure of the compound must be able to provide an H or an electron and consume the oxygen present. The mechanism of action of antioxidants can be summarized in the following three aspects: 1. Antioxidants generally have a higher standard potential and are subjected to oxidative damage before the drug. 2. Antioxidants act as acceptors of free radicals and inhibit the free radical chain reaction process. 3. They impede the formation of free radicals and block the chain reaction in the autoxidation reaction.

Subtypes of Pharmaceutical Antioxidant Excipients

Synthetic Antioxidants

Synthetic antioxidants are chemically synthesized compounds that possess strong antioxidant properties. They effectively scavenge free radicals and prevent oxidation. Examples of synthetic antioxidant excipients include butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and propyl gallate.

Natural Antioxidants

Natural antioxidants are derived from natural sources and offer a more sustainable and potentially safer alternative to synthetic antioxidants. These excipients exhibit antioxidant activity due to the presence of bioactive compounds like polyphenols and flavonoids. Examples of natural antioxidant excipients include vitamin E (tocopherols), ascorbic acid (vitamin C), and rosemary extract.

Synergistic Blends

Synergistic blends combine different antioxidants to provide enhanced protection against oxidative degradation. These blends often have complementary mechanisms of action, resulting in a synergistic effect greater than that of individual antioxidants. Some common combinations include ascorbic acid with tocopherols or ascorbyl palmitate with BHA.

To Choose an Antioxidant

Whether pharmaceutical preparations need to choose antioxidants, and the choice of antioxidants and their dosage, and the drug's dosage form, physical and chemical properties, the pH value of the liquid, the validity period of the preparation and packaging containers, etc., and should be decided after experimental research, and need to follow the following principles of selection:

1. Addition of antioxidants to reducing drugs susceptible to oxidation
2. Antioxidants should be highly effective and safe.
3. Avoid changes in the compatibility of API and antioxidants.
4. According to the pH value of the drug solution to choose antioxidants
5. Use with antioxidant synergist.


Pharmaceutical antioxidant excipients play a crucial role in protecting drugs from oxidative degradation, maintaining their stability, and extending their shelf life. With the right selection of antioxidant excipients, pharmaceutical formulations can be safeguarded against the harmful effects of oxidation, ensuring the delivery of safe and effective medications to patients. Partnering with Protheragen-ING, a reputable supplier, ensures the availability of high-quality excipients and supports the development of stable and efficacious pharmaceutical products. If you have any excipient requirements, please contact us by phone or email, and we will respond within 2-4 working days.

Cat Product Name Cas Details Chemical Structure
PIE-0081 Butylated Hydroxytoluene 128-37-0 View Details APIs
PIE-0082 Butylated Hydroxyanisole 25013-16-5 View Details APIs
PIE-0085 Pentetic Acid 67-43-6 View Details APIs
PIE-0102 Ascorbyl Palmitate 137-66-6 View Details APIs
PIE-0108 potassium metabisulfite 16731-55-8 View Details APIs
PIE-0123 Propyl Gallate 121-79-9 View Details APIs
PIE-0126 Gallic Acid Monohydrate 5995-86-8 View Details APIs
PIE-0127 Gallic Acid Anhydrous 149-91-7 View Details APIs
PIE-0128 Ethyl gallate 831-61-8 View Details APIs
PIE-0129 Methyl Gallate 99-24-1 View Details APIs
PIE-0130 Octyl Gallate 1034-01-1 View Details APIs
PIE-0131 Dodecyl gallate 1166-52-5 View Details APIs
PIE-0132 Gallic acid stearyl ester 10361-12-3 View Details APIs
PIE-0133 Pyrogallol 87-66-1 View Details APIs
PIE-0135 Ellagic acid 476-66-4 View Details APIs
PIE-0138 Neohesperidin 13241-33-3 View Details APIs
PIE-0139 citrus bioflavonoids 12002-36-7 View Details
PIE-0144 Ferulic Acid 1135-24-6 View Details APIs
PIE-0167 L-Cysteine hydrochloride monohydrate 7048-04-6 View Details APIs
PIE-0294 Sodium metabisulphite 7681-57-4 View Details APIs


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