Pilocarpine Nitrate API is a pharmaceutical active ingredient belonging to the class of direct-acting cholinergic and muscarinic agonists. It is the nitrate salt of pilocarpine and is primarily associated with ophthalmic pharmaceutical formulations. Pilocarpine acts by stimulating muscarinic receptors and is used in formulations where cholinergic activity is required, including ophthalmic products designed to reduce intraocular pressure. Pilocarpine Nitrate is identified by CAS Number 148-72-1, with the molecular formula C₁₁H₁₇N₃O₅ and molecular weight 271.27 g/mol.
Pilocarpine Nitrate is also known as Pilocarpine Mononitrate and is described pharmaceutically as the mononitrate salt of pilocarpine. The USP monograph specifies the substance as C₁₁H₁₆N₂O₂·HNO₃ with a molecular weight of 271.27. Current USP information specifies an assay range of 98.5% to 101.0% on the dried basis, making assay control an important part of API quality evaluation.
Pilocarpine Nitrate is a crystalline pharmaceutical substance. The current USP monograph specifies a melting range of 171°C to 176°C with decomposition, with the difference between the beginning and end of melting not exceeding 3°C. Its specific rotation is +79.5° to +82.5°, determined using a 20 mg/mL aqueous test solution. The monograph also specifies loss on drying of not more than 2.0%, determined after drying at 105°C for two hours.
For pharmaceutical manufacturing and quality control, identification and purity testing of Pilocarpine Nitrate are important because stereochemical and related-substance characteristics can influence API quality. USP identification includes infrared spectroscopy together with a chemical identification reaction. The substance is also required to comply with tests for readily carbonizable substances and chloride.
Pilocarpine is a cholinergic muscarinic agonist. In ophthalmic pharmaceutical applications, pilocarpine-containing formulations have historically been used to produce miosis and increase aqueous humor outflow, thereby helping reduce intraocular pressure. Pilocarpine Nitrate ophthalmic preparations are sterile aqueous formulations, and the USP ophthalmic solution monograph specifies a pH range of 4.0 to 5.5 for the finished ophthalmic dosage form. This pH value applies to the ophthalmic solution and should not be incorrectly presented as the universal pH specification of the dry API.
Pilocarpine Nitrate API is therefore relevant to pharmaceutical manufacturers developing ophthalmic formulations and other products requiring pilocarpine as the active pharmaceutical ingredient. Proper control of assay, moisture, identification, optical rotation, melting characteristics and related substances supports consistent pharmaceutical manufacturing.
Quality evaluation of Pilocarpine Nitrate API should follow the applicable pharmacopoeial requirements and the manufacturer's approved specification. The current USP monograph provides a quantitative assay range of 98.5–101.0% on the dried basis. Unlike some APIs where assay is performed by HPLC, the USP Pilocarpine Nitrate assay is based on non-aqueous potentiometric titration using 0.1 N perchloric acid, with each mL equivalent to 27.13 mg of Pilocarpine Nitrate. Therefore, the CMS should not incorrectly describe the USP assay as “HPLC 98.0–102.0%.”
For pharmaceutical quality control, additional analytical evaluation can include identification by IR, specific rotation, loss on drying, melting range, related substances, inorganic impurities and other tests required by the applicable regulatory specification. The available USP monograph does not establish universal numerical limits for heavy metals, total impurities or pH of the dry API, so these fields should not be populated with invented values.
Pilocarpine Nitrate should be handled and stored according to the applicable pharmaceutical specification. USP specifies preservation in tight, light-resistant containers.
Pilocarpine Nitrate API is an established pharmaceutical ingredient with a defined pharmacopoeial quality profile. Its CAS number, molecular identity, assay, melting range, specific rotation and loss-on-drying requirements make it suitable for structured pharmaceutical API documentation and quality assessment. For manufacturers and pharmaceutical developers, accurate specification control is particularly important when the API is intended for ophthalmic formulations.
The combination of verified chemical identity, pharmacopoeial assay requirements and controlled physical and analytical characteristics makes Pilocarpine Nitrate an important API for pharmaceutical development and manufacturing. All final release specifications should be aligned with the applicable current pharmacopoeial monograph, regulatory requirements and approved product specification rather than using generic small-molecule API limits.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 2.0% |
| Residue on Ignition | NMT 0.2% |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 1.0% |