Epinephrine, Full Product Series

Product Overview

Epinephrine (also known as Adrenaline) is a catecholamine hormone secreted by the human adrenal medulla and is one of the longest-used and most centrally important emergency drugs in clinical practice. Its chemical name is (R)-4-[2-(methylamino)-1-hydroxyethyl]-1,2-benzenediol; it contains one chiral carbon atom, and the pharmaceutical form is the R configuration (levorotatory) — the R(−)-isomer is more potent than the S(+)-isomer.

Mechanism of action: non-selective agonism of α and β adrenergic receptors — α receptor agonism constricts small arteries of the skin, mucosa, and viscera, rapidly raising blood pressure, reducing capillary permeability, and alleviating tissue edema; β₁ receptor agonism enhances myocardial contractility, accelerates heart rate, and increases cardiac output; β₂ receptor agonism relaxes bronchial smooth muscle, relieves laryngeal edema and bronchospasm, and inhibits further release of allergic mediators from mast cells and basophils.

The meaning of “full series”: this series extends from the epinephrine free base core into multiple pharmaceutical salt forms and dosage-form APIs. The free base itself is very slightly soluble in water but readily forms water-soluble salts with acids, giving rise to the hydrochloride (injection pH 2.5–5.0), the bitartrate/hydrogen tartrate (C₁₃H₁₉NO₉, MW 333.29, CAS 51-42-3, the official USP／BP reference-standard salt; eye drops pH 3.0–3.8; also widely used in local anesthetic combinations), and the borate complex (bufferable to physiological pH 5.5–7.6, less irritating for ophthalmic use). These salt forms differ significantly in physicochemical parameters (solubility, pH, loss on drying, hygroscopicity) and are not simply interchangeable in finished formulations — for example, the bitartrate has loss on drying ≤0.5% versus ≤2.0% for the free base, and the pH of 1% aqueous solutions is 2.8–4.0 versus a broader 2.5–5.0, respectively. This is exactly the value of “full series” supply for multi-dosage-form customers.

Stability profile: the catechol (o-diphenol) structure is extremely prone to oxidation — upon exposure to air or daylight it first oxidizes to adrenochrome, turning pink, and then forms melanin-like substances that turn brown, with potency declining accordingly; aqueous solutions readily racemize at room temperature or upon heating (faster at pH<4). Therefore the API must be stored protected from light, tightly sealed, and in a cool place; injections are commonly nitrogen-filled and protected with sulfite-class antioxidants; solutions that have changed color or developed precipitates must not be used.

Technical Specifications

• Standards: CHP／USP／EP
• Specification: 0.99 (purity ≥99.0%, HPLC); ChP requires not less than 98.5% C₉H₁₃NO₃ calculated on the dried basis; USP 97.0%–100.5% (NIFDC chemical reference standard batch 100154-202307, HPLC assigned value 99.5%)
• CAS No.: 51-43-4 (free base, EINECS 200-098-7, UNII YKH834O4BH); bitartrate 51-42-3
• Molecular formula: C₉H₁₃NO₃ (free base); bitartrate C₉H₁₃NO₃·C₄H₆O₆ (C₁₃H₁₉NO₉)
• Molecular weight: 183.21 (ChP, NIFDC, EPA; NIST records 183.2044); monoisotopic/exact mass 183.0895; bitartrate 333.29
• Appearance: white or almost white crystalline powder/fine crystalline granules; odorless, bitter taste; color gradually deepens on exposure to light and air (ChP “white or almost white crystalline powder”; USP “white to off-white microcrystalline powder or granules”; BP “white to grayish-white crystalline powder”)
• Purity (HPLC): ≥ 99.0%
• Melting point: 206–212 ℃, melting with simultaneous decomposition (ChP listed value); Merck Index and other sources record approx. 211–215 ℃ (decomp.). The bitartrate melting point is approx. 147–152 ℃ (decomp., USP) or approx. 155 ℃ (decomp.)
• Specific optical rotation: −50.0° to −53.5° (consistent across ChP／USP／BP／JP; determined on a solution prepared with hydrochloric acid solution 9→200 containing 20 mg per 1 mL)
• Solubility: very slightly soluble in water; insoluble in ethanol, chloroform, ether, fixed oils, or volatile oils; freely soluble in mineral acids or sodium hydroxide solutions; insoluble in ammonia solution or sodium carbonate solution. Water solubility varies with pH, with minimum solubility at approx. pH 9.4
• Acid dissociation constant (pKa): 8.66 (25 ℃)
• Related substances: ketone bodies (adrenalone; absorbance at 310 nm not more than 0.05), norepinephrine limit (not more than 4.0% by ChP TLC), etc., tested per the pharmacopoeias
• Loss on drying／sulfated ash: loss on drying over phosphorus pentoxide under reduced pressure for 18 hours not more than 1.0%; sulfated ash not more than 0.1%
• Storage conditions: protect from light, seal tightly under reduced pressure, and store in a cool place (not exceeding 20 ℃); sensitive to air and light — sealed storage protected from light at 2–8 ℃ is recommended; avoid contact with alkalis, oxidizing agents, and metal salts such as iron and copper

Applications

• Emergency treatment of anaphylactic shock and severe allergic reactions (type I hypersensitivity): auto-injector pens (pre-filled) are used for immediate self-/caregiver administration by individuals at elevated risk of allergic reactions, covering systemic allergic reactions caused by insect stings/bites, allergen immunotherapy, foods, drugs, diagnostic substances (such as contrast media), as well as idiopathic or exercise-induced anaphylaxis. 0.3 mg (0.3 mg/0.3 mL, 1:1000) for body weight ≥30 kg; 0.15 mg (0.15 mg/0.3 mL, 1:2000) for 15–30 kg; AUVI-Q and others also offer a 0.1 mg strength; inject into the anterolateral thigh — may be injected through clothing; repeat with a new device after 5 minutes if necessary. This is emergency supportive therapy and does not replace subsequent medical care
• Cardiopulmonary resuscitation for cardiac arrest: 0.25–0.5 mg diluted in 10 mL normal saline for intravenous injection (or intracardiac injection), combined with cardiac compression, artificial respiration, and correction of acidosis; for electrically induced arrest, may be combined with defibrillation or lidocaine
• Acute bronchial asthma attacks: 0.25–0.5 mg subcutaneously, onset in 3–5 minutes with duration of approx. 1 hour; repeat every 4 hours if necessary
• Combination with local anesthetics (a key salt-form scenario): added to local anesthetics at approx. 1:200000–1:500000 (mixture concentration 2–5 μg/mL, total not exceeding 0.3 mg) to delay absorption, prolong anesthesia, and reduce surgical-field bleeding. The bitartrate is well established in combination with amide-type local anesthetics (bupivacaine, articaine, lidocaine, prilocaine); dentistry commonly uses lidocaine 1:100,000 or 1:50,000 epinephrine combinations
• Ophthalmic and ENT topical use: eye drops (0.1%) for lowering intraocular pressure in open-angle glaucoma, mydriasis, and conjunctival decongestion; nasal drops (0.1%) and gauze packing (1:20000–1:1000) for nasal mucosal and gingival bleeding; the choice of ophthalmic salt form affects tolerability — the bitartrate causes more stinging on instillation than the hydrochloride or borate complex
• Others: urticaria, hay fever, serum sickness reactions, etc.; epinephrine oil injection (1 mL:1 mg)
• Full-series supply and CMO: supply of APIs from the free base to each salt form, analytical method development and validation, impurity reference standards (adrenalone, norepinephrine, etc.), salt-form and polymorph screening, antioxidant and light-protection stability studies (sulfite antioxidants, nitrogen blanketing, pH 2.2–5.0 control), clarity and color-change evaluation, and GMP scale-up and CMO／CDMO contract manufacturing

Safety notice: This product is an active pharmaceutical ingredient (API) intended only for legitimate industrial, research, and pharmaceutical manufacturing use; it is not for self-medication guidance. Epinephrine is a prescription drug. It is contraindicated in patients with hypertension, organic heart disease, coronary artery disease, diabetes, hyperthyroidism, digitalis intoxication, traumatic and hemorrhagic shock, and cardiac asthma; auto-injector pens must not be administered intravenously and must not be injected into the buttock, fingers, hands, or feet; solutions that are pink or darker than faintly yellow, or that contain precipitate or foreign matter, must not be used. The bitartrate is GHS-classified as acute oral toxicity category 1 (H300); strict protection is required during handling.

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