Epinephrine Injection (Auto-Injector Pen)

Product Overview

Epinephrine (also known as Adrenaline) is a catecholamine hormone secreted by the human adrenal medulla and one of the longest-used emergency drugs in clinical practice. Its structure contains one chiral carbon atom (the pharmaceutical form is the R configuration, which is levorotatory), and the R(−)-isomer is more potent than the S(+)-isomer.

Mechanism of action: As a non-selective α- and β-adrenergic receptor agonist — activation of α receptors constricts cutaneous, mucosal and visceral blood vessels, rapidly raising blood pressure and reducing tissue edema; activation of β₁ receptors enhances myocardial contractility, accelerates heart rate and increases cardiac output; activation of β₂ receptors relaxes bronchial smooth muscle, relieves laryngeal edema and bronchospasm, and inhibits further release of allergic mediators from mast cells and basophils.

Stability characteristics: The molecule contains a catechol (ortho-dihydroxybenzene) structure and is highly susceptible to oxidation — aqueous solutions readily undergo racemization at room temperature or on heating (racemization is faster at pH < 4); on exposure to air or light it first turns pink due to oxidation to adrenochrome, then turns brown as melanin-like substances form, with a corresponding loss of potency. The API therefore requires protection from light, tight sealing and cool storage; formulations must be protected from light and periodically inspected visually for clarity and color.

Technical Specifications

• Standards: CHP/USP/EP
• Specification: 0.99 (purity ≥99.0%, HPLC); calculated on the dried basis, ChP requires not less than 98.5% of C₉H₁₃NO₃, and USP requires 97.0%–100.5%
• CAS No.: 51-43-4 (EINECS 200-098-7; UNII YKH834O4BH)
• Molecular formula: C₉H₁₃NO₃
• Molecular weight: 183.21 (ChP, NIFDC reference standard); NIST/other literature reports 183.20 or 183.2044; exact mass 183.0895
• Appearance: White or off-white crystalline powder / fine crystalline granules; odorless, bitter taste; color gradually darkens on exposure to light and air (all pharmacopoeias describe it consistently: ChP “white or off-white crystalline powder”, USP “white to nearly white microcrystalline powder or granules”)
• Purity (HPLC): ≥ 99.0% (NIFDC chemical reference standard batch 100154-202307 assigned value by HPLC: 99.5%)
• Melting point: 206–212 °C, melting with simultaneous decomposition (ChP value); other literature and the Merck Index report approximately 211–215 °C (decomposition)
• Specific optical rotation: −50.0° to −53.5° (determined on a solution prepared with hydrochloric acid solution 9→200 containing 20 mg per 1 mL; consistent across ChP/USP/BP/JP)
• Solubility: Very slightly soluble in water; insoluble in ethanol, chloroform, ether, fatty oils or volatile oils; freely soluble in mineral acids or sodium hydroxide solution; insoluble in ammonia solution or sodium carbonate solution. Water solubility varies with pH, with minimum solubility at approximately pH 9.4
• Acidity coefficient (pKa): 8.66 (25 °C)
• Related substances: Keto bodies (absorbance at 310 nm not more than 0.05), norepinephrine limit (ChP TLC method, not more than 4.0%), etc., tested per pharmacopoeia
• Loss on drying: Dried under reduced pressure over phosphorus pentoxide for 18 hours; weight loss not more than 1.0%; residue on ignition not more than 0.1%
• Storage conditions: Protected from light, tightly sealed under reduced pressure, stored in a cool place (not exceeding 20 °C); sensitive to air and light — sealed storage at 2–8 °C protected from light is recommended

Applications

• Emergency treatment of anaphylactic shock and severe allergic reactions (type I hypersensitivity): Auto-injector pens (prefilled) are used for immediate self-/caregiver administration in individuals with a history of allergy or elevated allergic risk, indicated for systemic allergic reactions caused by Hymenoptera stings (bees, wasps, hornets, yellow jackets, fire ants), biting insects, allergen immunotherapy, foods, drugs, diagnostic substances (e.g., contrast media) and other allergens, as well as idiopathic or exercise-induced anaphylaxis. Adults and patients weighing ≥30 kg: 0.3 mg (0.3 mg/0.3 mL, 1:1000); patients weighing 15–30 kg: 0.15 mg (0.15 mg/0.3 mL, 1:2000); inject into the anterolateral thigh muscle (may be given through clothing), and repeat with a new device 5 minutes after the first dose if necessary. These devices are emergency supportive therapy and are not a substitute for subsequent medical or hospital care
• Cardiopulmonary resuscitation in cardiac arrest: For cardiac arrest caused by anesthetic and surgical accidents, drug poisoning or cardiac conduction block; 0.25–0.5 mg diluted with 10 mL of normal saline for intravenous injection (or intracardiac injection), combined with cardiac compression, artificial respiration and correction of acidosis; for electrically induced cardiac arrest, may be combined with electrical defibrillation or lidocaine resuscitation
• Acute bronchial asthma attacks: Subcutaneous injection of 0.25–0.5 mg, effective within 3–5 minutes, lasting approximately 1 hour; may be repeated every 4 hours if necessary
• Combination with local anesthetics: Added to local anesthetics at approximately 1:200000–1:500000 (concentration in the mixture 2–5 μg/mL, total dose not exceeding 0.3 mg) to delay local anesthetic absorption, prolong anesthesia and reduce bleeding at the surgical site
• Other: Applied topically to stop nasal mucosal and gingival bleeding; used for urticaria, hay fever, serum reactions, etc.
• Formulation and manufacturing: For formulation development of emergency dosage forms such as injections, prefilled auto-injector pens and prefilled syringes; studies on light protection and antioxidant stability (including sulfite antioxidants and pH 2.2–5.0 control); clarity and color change evaluation; as well as GMP scale-up and CMO/CDMO contract manufacturing

Safety notice: This product is an active pharmaceutical ingredient (API) intended solely for legitimate industrial, research and pharmaceutical manufacturing use, and does not constitute self-administration guidance. Epinephrine is a prescription drug. It is contraindicated in patients with hypertension, organic heart disease, coronary artery disease, diabetes, hyperthyroidism, digitalis poisoning, traumatic and hemorrhagic shock, or cardiac asthma. Auto-injector pens must not be injected intravenously or into the buttocks, fingers, hands or feet. Do not use if the solution is pink or darker than slightly yellow, or if precipitate or particulate matter is present.

Product information: please contact us. This information is for reference only.