Pefloxacin is a synthetic fluoroquinolone antibacterial active pharmaceutical ingredient used in pharmaceutical applications. The active moiety is chemically identified as Pefloxacin, while the pharmaceutical salt form is commonly represented by Pefloxacin Mesilate Dihydrate.
Pefloxacin has the molecular formula C17H20FN3O3, molecular weight 333.36 g/mol, and CAS Number 70458-92-3. FDA's Global Substance Registration System identifies Pefloxacin as an achiral chemical substance with no defined stereocenters.
For the mesilate salt, the commonly referenced pharmaceutical form is Pefloxacin Mesilate Dihydrate, CAS Number 149676-40-4, molecular formula C18H28FN3O8S, and molecular weight 465.5 g/mol. PubChem confirms the CAS number, formula and molecular weight.
Pefloxacin Mesilate Dihydrate is described in the British Pharmacopoeia/European Pharmacopoeia monograph as a fine, white or almost white powder. It is freely soluble in water, slightly soluble in ethanol (96%), and very slightly soluble in methylene chloride.
The monograph specifies the content of Pefloxacin Mesilate Dihydrate at 98.5% to 101.5%, calculated on the anhydrous substance. The API is therefore subject to defined pharmacopoeial quality controls covering identity, related substances, water, sulfated ash and assay.
The pharmacopoeial identification procedure includes infrared absorption spectrophotometry and thin-layer chromatography. The IR identification uses Pefloxacin Mesilate Dihydrate CRS as the comparison standard, while TLC is used to confirm the characteristic material.
These analytical controls help establish the identity and quality of Pefloxacin Mesilate Dihydrate before release for pharmaceutical manufacturing.
Related substances are controlled by liquid chromatography. The pharmacopoeial monograph establishes a limit of NMT 0.10% for each unspecified impurity and NMT 0.20% for total impurities. The reporting threshold is 0.05%.
The monograph also identifies several potential impurities, including norfloxacin and other quinolone-related compounds. This impurity profile is important for controlling process-related and degradation-related substances during Pefloxacin API manufacturing.
Because the pharmaceutical form is a dihydrate, water content is an important quality attribute. The pharmacopoeial specification establishes 7.0% to 8.5% water. This is preferable to using a generic loss-on-drying specification because the material is specifically defined as a dihydrate.
The monograph also specifies sulfated ash NMT 0.10%. The test is performed on 1.0 g of material.
The pharmacopoeial assay establishes a content range of 98.5% to 101.5%, calculated on the anhydrous substance. The official assay procedure uses potentiometric titration with 0.1 M perchloric acid rather than an HPLC assay. Therefore, for your CMS field titled Assay (HPLC), it is more accurate to identify the official method rather than incorrectly calling the pharmacopoeial assay HPLC.
Pefloxacin belongs to the fluoroquinolone class of antibacterial pharmaceutical ingredients. Pefloxacin and its mesilate salt have been associated with pharmaceutical antibacterial applications.
The API is relevant to pharmaceutical manufacturing, antimicrobial research, analytical development and fluoroquinolone-based pharmaceutical formulations.
Pefloxacin Mesilate Dihydrate requires controlled manufacturing and purification to achieve the pharmacopoeial requirements for assay, related substances, water and sulfated ash.
The BP/Ph. Eur. monograph specifies storage in an airtight container and protected from light.
For commercial pharmaceutical applications, the exact API form should always be identified because Pefloxacin, Pefloxacin Mesilate, and Pefloxacin Mesilate Dihydrate have different CAS numbers, molecular formulas and molecular weights.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| pH (1% Solution) | 3.5–4.5 |
| Individual Impurity | NMT 0.10% |
| Total Impurities | NMT 0.20% |
| Water Content | 7.0–8.5% |