Evaluation of physicochemical properties as supporting information on quality control of raw materials and veterinary pharmaceutical formulations

Abstract

This study aimed to show that the physicochemical proprieties obtained by Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), and scanning electronic microscopy (SEM) can be useful tools for evaluating the quality of active pharmaceutical ingredients (APIs) and pharmaceutical products. In addition, a simple, sensitive, and efficient method employing HPLC-DAD was developed for simultaneous determination of lidocaine (LID), ciprofloxacin (CFX) and enrofloxacin (EFX) in raw materials and in veterinary pharmaceutical formulations. Compounds were separated using a Gemini C₁₈ (250 mm × 4.6 mm, 5 µm) Phenomenex^® column, at a temperature of 25 °C, with a mobile phase containing 10 mM of phosphoric acid (pH 3.29): acetonitrile (85.7:14.3, v/v) and a flow rate of 1.5 mL/min. Physicochemical characterization by TG, FTIR, and SEM of raw materials of LID, CFX, and EFX provided information useful for the evaluation, differentiation, and qualification of raw materials. Finally, the HPLC method was proved to be useful for evaluation of raw material and finished products, besides satisfying the need for an analytical method that allows simultaneous determination of EFX, CFX, and LID, which can also be extended to other matrices and applications.

Keywords: HPLC; Physicochemical characterization; Quality control; Raw material; Veterinary pharmaceutical formulation.

Graphical abstract

Fig. 1

FTIR spectra of (A) lidocaine (LID), (B) ciprofloxacin (CFX), and (C) enrofloxacin (EFX).

Fig. 2

Thermogravimetric curve (TGA) and derivative thermogravimetric curve (DrTGA) of (A) lidocaine (LID), (B) ciprofloxacin (CFX), and (C) enrofloxacin (EFX).

Fig. 3

Scanning electron microscopy (SEM) images of lidocaine (LID) at magnifications of 200 × (A) and 500 × (B), ciprofloxacin (CFX) at magnifications of 200 × (C) and 500 × (D), and enrofloxacin (EFX) at magnifications of 200 × (E) and 500 × (F).

Fig. 4

Chromatogram referring to the optimized method for analysis of (1) Lidocaine (LID), (2) ciprofloxacin (CFX), and (3) enrofloxacin (EFX). Conditions: Gemini C₁₈ (250 mm × 4.6 mm i.d., 5.0 µm) Phenomenex^® column, mobile phase consisting of 10 mM of phosphoric acid (pH 3.29):acetonitrile (85.7: 14.3, v/v) at a flow rate of 1.5 mL/min, detection at 210 and 280 nm using a DAD, temperature at 25 °C, injection volume of 10 µL, and isocratic mode.