Sibutramine is a synthetic centrally acting compound that was historically developed for the management of obesity. For pharmaceutical API identification, the commonly documented drug-substance form is Sibutramine Hydrochloride Monohydrate, CAS No. 125494-59-9. The FDA CMC documentation distinguishes this form from anhydrous sibutramine hydrochloride (CAS 84485-00-7) and the free base (CAS 106650-56-0).
Sibutramine Hydrochloride Monohydrate has the chemical name N-{1-[1-(4-Chlorophenyl)cyclobutyl]-3-methylbutyl}-N,N-dimethylamine hydrochloride monohydrate. Its molecular formula is C17H29Cl2NO and its molecular weight is approximately 334.33 g/mol. The FDA CMC documentation describes the material as a white to cream crystalline powder.
The API is a racemic compound containing the (+) and (−) enantiomers. Analytical literature has described HPLC methods for determining sibutramine hydrochloride and its impurities in bulk drug substance and pharmaceutical formulations.
Sibutramine belongs to the phenethylamine-related class of centrally acting compounds. Its structure contains a 4-chlorophenyl cyclobutyl group and a dimethylamino side chain. In its hydrochloride monohydrate form, the basic amine is present as the hydrochloride salt together with one molecule of water of crystallization.
The distinction between the anhydrous hydrochloride and monohydrate is important for API documentation because the two forms have different molecular formulas, molecular weights and CAS numbers. The FDA CMC record specifically identifies 125494-59-9 for sibutramine hydrochloride monohydrate.
The compound has historically been investigated using reversed-phase and chiral liquid chromatography. Published analytical work describes HPLC methods for quantitative determination of sibutramine hydrochloride and related impurities, demonstrating the importance of chromatographic control for API quality.
Sibutramine was historically developed as an anti-obesity medicine. Its pharmacological activity is associated with inhibition of norepinephrine and serotonin reuptake, with a lesser effect on dopamine reuptake. These mechanisms were associated with appetite suppression and increased satiety.
Because sibutramine has been withdrawn or restricted in multiple markets following safety concerns, its regulatory status differs substantially from that of currently marketed anti-obesity APIs. Therefore, API manufacturing, distribution and pharmaceutical use should be evaluated against the applicable laws, regulatory approvals and market-specific requirements.
For technical API documentation, it is particularly important to identify whether the material is Sibutramine Hydrochloride Monohydrate, Sibutramine Hydrochloride Anhydrous or Sibutramine Free Base, rather than using “Sibutramine” without specifying the chemical form.
Sibutramine Hydrochloride Monohydrate can be evaluated using validated chromatographic and physicochemical analytical procedures. HPLC has been reported for assay and impurity determination, including analysis of the drug substance and a specified sibutramine-related impurity.
Relevant quality-control parameters may include identity, assay by HPLC, related substances, water content, residue on ignition, residual solvents, enantiomeric purity and chromatographic purity.
Published analytical literature reports a validated HPLC method for sibutramine hydrochloride monohydrate with an impurity identified as 5-(2R)-2-aminopropyl)-2-methoxybenzene sulphonamide. The study demonstrated the applicability of the method to bulk drug and formulations.
A historical FDA CMC record provides the drug-substance identity and physical description but does not establish every numerical CMS field as a current universal pharmacopeial release specification. Accordingly, values below are only given where they can be supported; otherwise the field is identified as specification-dependent or not universally established.
Manufacturing of Sibutramine Hydrochloride Monohydrate requires controlled synthesis, salt formation, crystallization and drying to achieve consistent drug-substance quality. Control of the hydrate state is particularly relevant because the monohydrate contains one molecule of water of crystallization and therefore differs from anhydrous sibutramine hydrochloride.
Analytical controls should confirm chemical identity, chromatographic purity, assay, water/hydrate content and relevant organic impurities. Where stereochemical purity is required, chiral chromatographic methods can be used to evaluate the enantiomeric composition. Published literature specifically describes chiral chromatography for sibutramine hydrochloride and its enantiomers.
The API should be manufactured and documented according to the applicable regulatory requirements for the intended market and use.
Sibutramine Hydrochloride Monohydrate should be packaged in suitable pharmaceutical-grade, tightly closed containers that protect the material from moisture, contamination and inappropriate environmental exposure.
Because the monohydrate represents a defined hydrated form, storage and packaging should maintain the validated physical and chemical characteristics of the API. Exact storage temperature, humidity controls and retest period should be established from the applicable stability data and manufacturer specification.
A pharmaceutical API documentation package may include:
Documentation should clearly state Sibutramine Hydrochloride Monohydrate, CAS 125494-59-9 rather than confusing it with the anhydrous hydrochloride CAS 84485-00-7.
Sibutramine Hydrochloride Monohydrate is a chemically defined pharmaceutical drug substance requiring careful control of salt form, hydrate state, chromatographic purity and related substances.
A quality-focused API manufacturing approach should use validated analytical methods, controlled crystallization and drying, appropriate moisture-protective packaging and comprehensive quality documentation. Because the regulatory status of sibutramine varies by jurisdiction and the substance has been withdrawn from several markets, all intended applications should be assessed against current regulatory requirements.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Residue on Ignition | NMT 0.1% |
| Heavy Metals | NMT 10 ppm |
| pH (1% Solution) | 4.0 – 6.0 |
| Individual Impurity | NMT 0.1% |
| Total Impurities | NMT 0.5% |
| Water Content | 4.5% – 6.0% |
| Melting Point | 190 – 200°C |