Separation and simultaneous high-performance liquid chromatographic determination of benzocaine and benzyl benzoate in a pharmaceutical preparation

Analytical investigation of styrax and benzoin balsams by HPLC- PAD-fluorimetry and GC-MS

An HPLC and GC study has been conducted on the aromatic oleoresins styrax and benzoin produced by several American, Mediterranean and East-Asian trees, and widely used in ancient civilisations for their therapeutic and odoriferous properties. Initial experiments were performed by HPLC-PAD-fluorimetry for the analysis of several aromatic components, and then completed by GC-MS for the characterisation of both aromatic and triterpenic derivatives. In this work, it was crucial to isolate from fresh natural exudates, and to characterise by two-dimensional NMR, some of the major constituents in order to extend the standard molecular pool prior to chromatographic identifications. This study reveals coniferyl benzoate as an excellent distinctive fluorescent biomarker of Siam benzoin substrate. It also confirms that fluorimetric-coupled detection is a powerful analytical tool for the identification of compounds in Hamamelidaceae extracts that are almost undetectable by UV. GC-MS was successfully applied to the determination of the botanical origin of Sumatra benzoin, and to the identification of lupeol [3beta-lup-20(29)-en-3-ol] for the first time in such balsam-type materials.

Productive degradation of the biocide benzylbenzoate by Acinetobacter sp. strain AG1 isolated from the River Elbe

From water sampled in the River Elbe, we isolated a bacterial strain able to use the biocidal compound benzylbenzoate as its sole source of carbon and energy under aerobic conditions. This isolate was tentatively assigned to the genus Acinetobacter due to its morphological, physiological and partial SSU rRNA gene sequence properties. The productive bacterial degradation of the biocide benzylbenzoate was demonstrated, and the catabolic sequence was elucidated biochemically. Growth experiments, along with enzymatic studies, demonstrated that strain Acinetobacter sp. AG1 hydrolyzed benzylbenzoate enzymatically to yield benzylalcohol and benzoate. Benzylalcohol was further transformed to benzoate via benzaldehyde. Benzoate was subsequently channeled via catechol into the oxoadipate pathway for further degradation.

A new validated method for the simultaneous determination of benzocaine, propylparaben and benzyl alcohol in a bioadhesive gel by HPLC

A new HPLC-RP method has been developed and validated for the simultaneous determination of benzocaine, two preservatives (propylparaben (nipasol) and benzyl alcohol) and degradation products of benzocaine in a semisolid pharmaceutical dosage form (benzocaine gel). The method uses a Nucleosil 120 C18 column and gradient elution. The mobile phase consisted of a mixture of methanol and glacial acetic acid (10%, v/v) at different proportion according to a time-schedule programme, pumped at a flow rate of 2.0 ml min(-1). The DAD detector was set at 258 nm. The validation study was carried out fulfilling the ICH guidelines in order to prove that the new analytical method, meets the reliability characteristics, and these characteristics showed the capacity of analytical method to keep, throughout the time, the fundamental criteria for validation: selectivity, linearity, precision, accuracy and sensitivity. The method was applied during the quality control of benzocaine gel in order to quantify the drug (benzocaine), preservatives and degraded products and proved to be suitable for rapid and reliable quality control method.

Quantification of benzocaine and its metabolites in channel catfish tissues and fluids by HPLC

Methods for extraction and gradient HPLC quantification were developed for benzocaine (BZ) and three of its metabolites to be used in conjunction with a reverse isotope technique. The metabolites were p-aminobenzoic acid (PABA), acetyl-p-aminobenzoic acid (AcPABA) and acetylbenzocaine (AcBZ). The matrixes studied were white muscle, red muscle, skin, liver, trunk kidney, head kidney, plasma and the bile of channel catfish. Analytes were validated for each of the compounds at 25 and 100 nmol per sample in the various tissues and fluids. The intraday variability (R.S.D.) was less than 13% in all tissues and fluids except for BZ in the liver. Recoveries varied from matrix to matrix for each analyte. The highest recoveries were obtained from plasma which ranged from 82.8-99.8% depending on the concentration. The average recovery of the compounds from tissues was between 50 and 78%, except for liver where the recovery of PABA and BZ was below 30%. Detection was by UV absorbance at 286 nm and the linear range was 2.5-15 nmol 100 ml-1 for all analytes. The method was selective; no interference peaks coeluted with the analytes.

Development and validation of chromatographic methods (HPLC and GC) for the determination of the active components (benzocaine, tyrothricin and menthol) of a pharmaceutical preparation

Methods are reported for the determination of tyrothricin and benzocaine by HPLC and menthol by GC in the analysis of throat lozenges (tablets) containing all three compounds. After optimization of the variables involved in both HPLC and GC the methods have been characterized and validated according to the guidelines of the Spanish Pharmacopoeia, and applied to both the monitoring of the manufacturing process and the quality control of the final product.