Gentamicin alters nitric oxide production in semicircular canals and otolith organs

Intratympanic gentamycine for Ménière's disease: is there a selective vestibulotoxic effect?

Purpose

The aim of our study is to investigate the effectiveness and safety of the treatment, based on vertigo diaries and pure tone audiograms.

Methods

The complete medical documentation of 105 definite patients suffering from Ménière’s disease was analyzed. In the studied group, nine patients were treated with intratympanic gentamycine. Long-term follow-up of the patients was carried out, using vertigo diaries, medical letters, anamnestic data, and pure tone audiograms. Audiometric results and vertigo complaints before and after treatment were contrasted using IBM SPSS V24 software.

Results

Based on our analysis, vertigo attacks appeared significantly less often after gentamycine treatment [p < 0.001; Odds ratio 0.003 (95% CI 0.001–0.012)], which confirms the efficacy of the therapy. Pure tone stages before and after the application of gentamycine were contrasted using the Mann–Whitney U test. When comparing the audiometric results of long-term follow-ups by using the logistic regression, a statistically significant difference was observed between the treated and not treated groups [p = 0.001; Odds ratio 0.141 (95% CI 0.064–0.313)], and based on the survivorship curve hearing impairment was more common in the not treated group which also supports our results. Based on the non-parametric test, there was no significant difference (p = 0.84) between the pure-tone stages of the control group and of those treated with gentamycine.

Conclusion

Our results indicate that intratympanic gentamycine is effective in controlling vertigo attacks, and there is no higher risk for hearing loss than in case of spontaneous progression of the disorder.

Preparative purification of gentamicin components using high-speed counter-current chromatography coupled with electrospray mass spectrometry

We developed a useful and preparative method based on high-speed counter-current chromatography with mass spectrometry (HSCCC/MS) to purify gentamicin C1a, C2/2a and C1 from standard powder. The analytes were purified on the HSCCC model CCC-1000 (multi-layer coil planet centrifuge) with a volatile two-phase solvent system composed of n-butanol/10% aqueous ammonia solution (50:50, v/v) and detected on an LCMS-2020EV quadrupole mass spectrometer fitted with an electrospray ionization (ESI) source system in positive ionization following scan mode (m/z 100-500). The HSCCC/ESI-MS peaks indicated that gentamicin C1a (m/z 450: [M+H](+)), C2/2a (m/z 464: [M+H](+)) and C1 (m/z 478: [M+H](+)) have the peak resolution values of 1.3 and 1.7 from 30 mg of loaded gentamicin powder. The HSCCC yielded 3.9 mg of gentamicin C1a, 12.6 mg of gentamicin C2/2a and 12.0 mg of gentamicin C1. These purified substances were analyzed by LC/MS with scan positive-mode. Based on the LC/MS chromatograms and spectra of the fractions, analytes were estimated to be over 95% pure. These gentamicin isomers of C1a, C2/2a and C1 were evaluated for their antibacterial activities. The overall results indicate that this approach of HSCCC/MS is a powerful technique for the purification of gentamicin components.