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Xolair
Xolair Injection Ingredients – Composition Explained
Apr 25, 2025
Peanut allergies are among the most common food allergens worldwide, affecting millions and sometimes causing severe reactions such as anaphylaxis. For people with allergies, understanding the composition of medications is crucial for safety and effectiveness.
Xolair (omalizumab) offers a targeted approach to managing allergic conditions. Unlike traditional oral medications, Xolair is an injectable biologic that blocks IgE antibodies, a key driver of allergic responses. Its formulation is preservative-free and contains only a few inactive ingredients, with no peanut, nut, or common food allergens, making it a viable option for many patients who need alternatives to conventional treatments.
In this article, we will explore Xolair’s composition, detailing its active and inactive ingredients, and compare its formulation to other allergy medications.
Key Takeaways
- Xolair’s active ingredient is omalizumab, a monoclonal antibody that blocks IgE to reduce allergic inflammation in asthma, chronic hives, and nasal polyps.
- Inactive ingredients include L-histidine, polysorbate 20, sucrose, water for injection, and histidine hydrochloride monohydrate—each selected for safety and formulation stability.
- Xolair comes in two forms: a lyophilized powder requiring reconstitution and a ready-to-use pre-filled syringe, both offering equivalent clinical results.
- The injection is free of preservatives, latex, gelatin, egg, and peanut derivatives, making it suitable for most patients with food or excipient allergies.
- Proper refrigeration and light protection are essential to maintain potency and prevent degradation of the biologic formulation.
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Active Ingredient in Xolair Injection
The primary active ingredient in Xolair is omalizumab, a recombinant DNA-derived humanized IgG1κ monoclonal antibody. This biologic binds to free immunoglobulin E (IgE) in the bloodstream, preventing it from attaching to mast cells and basophils—two cell types responsible for triggering allergic reactions.
By blocking IgE, omalizumab helps suppress the body’s allergic cascade and reduce inflammation. This mechanism makes it effective for multiple Xolair injection indications, including allergic asthma, chronic spontaneous urticaria, and nasal polyps. Healthcare providers determine the dosage of omalizumab based on the patient’s body weight and baseline serum IgE levels.
It’s important to note that omalizumab is produced using recombinant DNA technology in Chinese hamster ovary (CHO) cells, which ensures high purity, batch consistency, and suitability for human use. This biologic’s manufacturing process sets it apart from many traditional drugs.
Inactive Components of Xolair Injection Formulations
In addition to its active antibody, Xolair contains a small number of inactive ingredients, known as excipients, which help maintain its stability, pH, and solubility without contributing to the therapeutic effect.
These inactive components include:
- L-histidine: Functions as a buffering agent to regulate pH
- Polysorbate 20: a surfactant that keeps the protein dissolved and stable
- Sucrose: Acts as a stabilizer and bulking agent, especially in the powdered form
- Water for Injection: Used in pre-filled syringes or for reconstitution
- Histidine Hydrochloride Monohydrate: Assists with maintaining an optimal pH
Each ingredient is pharmaceutical-grade and carefully selected to be compatible with subcutaneous administration. None of the components of omalizumab comes from common food allergens.
Differences Between Xolair Injection Formulations
Xolair is available in two pharmaceutical formulations, both offering the same therapeutic effect but suited for different clinical needs:
Lyophilized Powder for Reconstitution
- Must be reconstituted with sterile water prior to injection
- Contains omalizumab, sucrose, L-histidine, and polysorbate 20
- Typically used in clinical settings requiring precise dose preparation
Pre-Filled Syringe
- Ready-to-use formulation that requires no reconstitution
- Includes omalizumab, polysorbate 20, L-histidine, and water
- Offers enhanced convenience for patients receiving ongoing or home-based treatment
Both versions maintain similar safety and efficacy profiles, but the choice depends on clinical setting, treatment frequency, and patient needs. While healthcare providers often prefer the lyophilized powder in hospital settings, the pre-filled syringe works best for outpatient or self-administration scenarios.
Potential Allergens in Xolair Injection Ingredients
Despite being an allergy treatment, it’s essential to understand the allergenic risk profile of Xolair’s ingredients. Here’s what patients and clinicians should know:
- No Preservatives: Reduces the risk of preservative-related hypersensitivity.
- No Latex: The vial stopper and syringe components are latex-free.
- No Animal-derived Ingredients: Suitable for those with egg, gelatin, or milk allergies.
- Rare Anaphylaxis Risk: Hypersensitivity to omalizumab itself, though rare, has been reported.
Patients with a history of drug-related allergic reactions should always inform their healthcare provider. Medical professionals must supervise all initial doses, and they should observe patients for a minimum of 30 minutes post-injection. Providers should have emergency management protocols in place for rare but serious allergic responses.
Storage and Stability Considerations for Xolair Injection
Proper handling of Xolair ensures its effectiveness and safety over time. Both formulations—lyophilized powder and pre-filled syringe—must be stored under specific conditions:
- Refrigeration: Keep between 2°C and 8°C (36°F to 46°F)
- Protect from Light: Store in the original packaging until use
- Do Not Freeze: Freezing can damage the monoclonal antibody
- Use After Reconstitution: Lyophilized powder should be used within 8 hours of reconstitution if stored at 2–8°C
Healthcare staff must verify storage compliance before use, as degraded protein structure can affect efficacy and patient safety. Following manufacturer guidelines ensures each dose performs as intended.
Conclusion
Xolair injection combines a carefully engineered active ingredient—omalizumab—with a minimal number of inactive components to support its stability and delivery. The medication’s preservative-free, latex-free, and allergen-conscious formulation makes it a strong candidate for patients with sensitive allergic profiles.
Whether administered via lyophilized powder or pre-filled syringe, knowing the composition of Xolair helps clinicians and patients make informed, safe decisions—particularly in the context of complex allergy management. As treatment protocols expand, understanding these details becomes even more essential in guiding patient care.
FAQs
1. What is Xolair used to treat?
Xolair treats moderate-to-severe allergic asthma, chronic spontaneous urticaria, and nasal polyps that don’t respond to standard treatments.
2. How is Xolair administered?
Providers administer it as a subcutaneous injection every 2 to 4 weeks, depending on the required dose and the condition being treated.
3. Can Xolair cause allergic reactions?
Yes, although rare, Xolair may cause anaphylaxis or other hypersensitivity reactions. Patients should be monitored after injection.
4. What is the active ingredient in Xolair?
The active ingredient is omalizumab, a monoclonal antibody that binds to IgE to reduce allergic responses.
5. Are there preservatives or animal products in Xolair?
No, Xolair does not contain preservatives, latex, or animal-derived ingredients.
6. How do providers determine the correct Xolair dose?
Dosing is based on body weight and blood IgE levels, particularly for patients with allergic asthma.
7. Can Xolair be stored at room temperature?
Practitioners must store Xolair in the refrigerator and protect it from light. Do not freeze the product.
References
West H. The 8 Most Common Food Allergies. Healthline. Published January 25, 2017. https://www.healthline.com/nutrition/common-food-allergies
Mayo Clinic. Allergies – Symptoms and Causes. Mayo Clinic. Published August 24, 2024. https://www.mayoclinic.org/diseases-conditions/allergies/symptoms-causes/syc-20351497
Omalizumab Injection. Cleveland Clinic. https://my.clevelandclinic.org/health/drugs/19805-omalizumab-injection