Study of the impurity profile of photodegradation in lomefloxacin hydrochloride ear drops using liquid chromatography combined with ion trap/time-of-flight mass spectrometry

RATIONALE

Lomefloxacin hydrochloride ear drops are highly unstable to light and prone to produce photodegradation impurities. These impurities might be related to the phototoxicity of lomefloxacin, which could seriously threaten the health of patients. In this article, the photodegradation impurity profile in lomefloxacin hydrochloride ear drops was studied for further improvement of quality control of the drug.

METHODS

By studying the chromatographic behavior of photodegradation impurities, the photodegradation impurities in lomefloxacin hydrochloride ear drops were separated and detected effectively. Liquid chromatography combined with ion trap/time-of-flight mass spectrometry was applied to characterize the structures of the photodegradation impurities in lomefloxacin hydrochloride ear drops.

RESULTS

The structures of 17 impurities in lomefloxacin hydrochloride ear drops were elucidated based on high-resolution MSn data in positive ion mode, 12 of them being unknown impurities.

CONCLUSIONS

The structural characteristics and fragmentation patterns of the photodegradation impurities were also studied. The study of the photodegradation impurity profile in lomefloxacin hydrochloride ear drops provides a scientific basis for quality control of these ear drops and ensures the safety of drug use by the public.

An In Vitro Model for Characterization of Drug Permeability across the Tympanic Membrane

Otic disorders, such as otitis media and hearing loss, affect a substantial portion of the global population. Despite this, oto-therapeutics, in particular those intended to treat hearing loss, have seen limited development and innovation. A significant factor to this is likely a result of the inherent costs and complexities of drug discovery and development. With in vitro 3D tissue models seeing increased utility for the rapid, high-throughput screening of drug candidates, it stands to reason that the field of otology could greatly benefit from such innovations. In this study, we propose and describe an in vitro 3D model, designed using a physiologically based approach, which we suggest can be used to estimate drug permeability across human tympanic membranes (TM). We characterize the permeability properties of several template drugs in this model under various growth and storage conditions. The availability of such cost-effective, rapid, high-throughput screening tools should allow for increased innovation and the discovery of novel drug candidates over the currently used animal models. In the context of this TM permeation model, it may promote the development of topical drugs and formulations that can non-invasively traverse the TM and provide tissue-targeted drug delivery as an alternative to systemic treatment, an objective which has seen limited study until present.

Does intraoperative ciprofloxacin-soaked gelfoam have adverse effects on graft success rate? A randomized, double-blind controlled trial

OBJECTIVES

The aim of this study was to evaluate whether intraoperative ciprofloxacin-soaked gelfoam is safe in tympanoplasty or not.

METHOD

In this randomized, double-blind controlled clinical study, we included 100 patients between 18 and 60 years old, having perforation ≥50% of the tympanic membrane and dry ear for at least 2 months who were a candidate for underlay tympanoplasty via postauricular approach. We used ciprofloxacin soaked gelfoam in the case group and betamethasone soaked gelfoam in the control group for packing the middle ear cavity and external auditory canal during their operation. The graft success rate and tympanogram after 6 months follow-up period was considered as the primary outcome. Also, we evaluated the postoperative hearing results 6 months after the surgery as the secondary outcomes.

RESULTS

Postoperative microscopic otoscopy showed a graft success rate of 100% (44/44) and 97.7% (42/43) in the case and control groups, respectively. The level of improvement between the two groups was not significant for air-bone gap (ciprofloxacin: 9.01 ± 7.89 dB, betamethasone 5.31 ± 10.53 dB, P = .160), and speech reception thresholds (SRT; ciprofloxacin: 10.23 ± 8.62 dB, betamethasone 7.33 ± 12.60 dB, P = .260). 93.2% of all the ears in the case group and 81.4% of those in the control group achieved postoperative air-bone gap within 20 dB, but the difference between them was not significant (P = .118).

CONCLUSIONS

We found that the application of ciprofloxacin impregnated gelfoam in the middle ear, and the external auditory canal had no adverse effect on the graft success rate in tympanoplasty.

LEVELS OF EVIDENCE

1b.

Necessities, opportunities, and challenges for tympanic membrane perforation scaffolding-based bioengineering

Tympanic membrane (TM) perforation is a global clinical dilemma. It occurs as a consequence of object penetration, blast trauma, barotrauma, and middle ear diseases. TM perforation may lead to otitis media, retraction pockets, cholesteatoma, and conductive deafness. Molecular therapies may not be suitable to treat perforation because there is no underlying tissue matrix to support epithelium bridging. Chronic perforations are usually reconstructed with autologous grafts via surgical myringoplasty. Surgical treatment is uncomfortable for the patients. The grafting materials are not perfect because they produce an opaque membrane, fail in up to 20% of cases, and are suboptimal to restore acoustic function. Millions of patients from developing parts of the world have not got access to surgical grafting due to operational complexities, lack of surgical resources, and high cost. These shortcomings emphasize bioengineering to improve placement options, healing rate, hearing outcomes, and minimize surgical procedures. This review highlights cellular, structural, pathophysiological, and perforation specific determinants that affect healing, acoustic and surgical outcomes; and integrates necessities relevant to bioengineered scaffolds. This study further summarizes scaffolding components, progress in scaffolding strategies and design, and engenders limitations and challenges for optimal bioengineering of chronic perforation.

Cytotoxicity of Ear Drop Excipients in Human and Mouse Tympanic Membrane Fibroblasts

Objective

Commercial ear drops contain ingredients reported to be inactive. We sought to evaluate such excipients for possible cytotoxicity on human and mouse tympanic membrane (TM) fibroblasts.

Study Design

Prospective, in vitro.

Setting

Tertiary academic center.

Subjects and Methods

Mouse and human TM fibroblasts were treated with 1:10 dilutions of benzalkonium chloride (BKC) 0.0025%, 0.006%, or 0.01%; benzyl alcohol 0.9%; polysorbate 80 (PSB) 2.5%; glycerin 2.4%; povidone 0.2%; or water (control), twice within 24 hours or 4 times within 48 hours, for 2 hours each time. Cells were placed back in growth media after the treatments. Cells were observed with phase-contrast microscopy until the cytotoxicity assay was performed.

Results

Mouse fibroblasts had lower survival in only the PSB-treated cells compared to the control ( P < .0001) after 24 hours. After 48 hours, PSB killed nearly all mouse fibroblasts ( P < .0001). BKC decreased fibroblast survival in a dose-dependent manner ( P < .001). In human TM fibroblasts, all excipients except povidone and benzyl alcohol after 24 hours and povidone after 48 hours reduced cell survival compared to control ( P = .012 to P < .0001). The cytotoxicity of BKC in human TM fibroblasts was also dose dependent (<.0001). PSB was less cytotoxic to human fibroblasts. Phase-contrast images mirrored the cytotoxicity findings.

Conclusion

Polysorbate 80 and benzalkonium chloride, at concentrations found in commercial ear drops, may be cytotoxic to human and mouse TM fibroblasts. “Inactive” ingredients may need to be considered when evaluating clinical outcomes with commercial ear drops.

Appropriateness of Otic Quinolone Use among Privately Insured US Patients

Objective

Considering emerging safety concerns involving otic quinolones, we assessed the extent of otic quinolone use for questionable indications.

Study Design

Descriptive cross-sectional study of a national sample of privately insured patients.

Setting

Outpatient encounters in the United States.

Subjects and Methods

Children and adults with outpatient pharmacy-dispensing claims for new prescriptions of otic or ophthalmic quinolones in 2017 were identified within the IBM MarketScan Commercial Claims & Encounters and the Medicare Supplemental Database. Each dispensing ≥30 days apart constituted a unique episode. Only claims with supporting ear-related diagnoses on outpatient encounters ±3 days of dispensing were considered. Ophthalmic drops were excluded if eye-related diagnoses were found ±30 days. Prescribing was classified as appropriate, questionable, or undetermined.

Results

We found 214,897 episodes in 200,270 patients. Adults were twice as likely as children to have otic treatment with questionable indications (6.2% vs 3.0%). Sensitivity analyses with broader time windows to ascertain diagnoses showed similar proportions of questionable use. Otalgia and cerumen impaction constituted 90% of questionable indications. Family physicians (6.8%) and internists (8.0%) had higher percentages of questionable use than other specialties.

Conclusion

Based on the demonstrated risks of quinolone ear drops, opportunities exist to decrease otic quinolone use, especially in adults.