Gentamicin Solution Research Articles

A mesoporous core-shell structure for pH-controlled storage and release of water-soluble drug

A novel pH-controlled delivery system has been developed based on hollow mesoporous silica spheres using pH-sensitive polyelectrolyte multilayer coated on the spheres as a switch to store and release gentamicin molecules (a model drug). The polyelectrolyte layers with an average thickness of 12 nm was coated on hollow mesoporous silica spheres through a layer-by-layer technique. Gentamicin molecules were successfully stored in these spheres by means of adjusting the gentamicin solution from pH 2 to pH 8. The storage capacity can reach 614.8 mg/g (34.11%) at an initial gentamicin concentration of 60 mg/ml. The controlled release of gentamicin molecules from this system has been achieved by simply changing the pH value in the release media. Therefore, this type of material is of potentials for the controlled drug release applications.

Evaluation of a combination of sodium hypochlorite and polyhexamethylene biguanide as an egg wash for red-eared slider turtles (Trachemys scripta elegans) to suppress or eliminate Salmonella organisms on egg surfaces and in hatchlings

To evaluate a combination of 2 nonantibiotic microbicide compounds, sodium hypochlorite (NaOCl) and polyhexamethylene biguanide (PHMB), as a treatment to suppress or eliminate Salmonella spp from red-eared slider (RES) turtle (Trachemys scripta elegans) eggs and hatchlings. 2,738 eggs from 8 turtle farms in Louisiana. Eggs were randomly sorted into 3 or, when sufficient eggs were available, 4 treatment groups as follows: control, pressure-differential egg treatment with NaOCl and gentamicin, NaOCl and PHMB bath treatment, and pressure-differential egg treatment with NaOCl and PHMB. Bacterial cultures were performed from specimens of eggs and hatchlings and evaluated for Salmonella spp. RES turtle eggs treated with NaOCl and PHMB as a bath (odds ratio [OR], 0.2 [95% confidence interval (CI), 0.1 to 0.3]) or as a pressure-differential dip (OR, 0.01 [95% CI, 0.001 to 0.07]) or with gentamicin as a pressure-differential dip (OR, 0.1 [95% CI, 0.06 to 0.2]) were significantly less likely to have Salmonella-positive culture results than control-group eggs. Concern over reptile-associated salmonellosis in children in the United States is so great that federal regulations prohibit the sale of turtles that are < 10.2 cm in length. Currently, turtle farms treat eggs with gentamicin solution. Although this has reduced Salmonella shedding, it has also resulted in antimicrobial resistance. Results of our study indicate that a combination of NaOCl and PHMB may be used to suppress or eliminate Salmonella spp on RES turtle eggs and in hatchlings.

In Vitro Evaluation and Targeting of E. Coli Internalized by Endothelial Cells using Albumin Microspheres Loaded with Gentamicin

ABSTRACTThe purpose of this study was to evaluate the use of microencapsulated form of gentamicin and the traditional solution form for its intracellular bactericidal effect. Bovine serumalbumin (BSA) microspheres loaded with gentamicin were prepared by using Mini Spray Dryer. Human microvascular endothelial cells (HMECs) were exposed to increasing concentrations of Escherichia coli leading to internalization of E. coli. The internalized bacteria were targeted using either the microencapsulated or the solution form of gentamicin. The treatment groups using gentamicin solution form and microsphere form showed almost 46% and 86% inhibition in the growth of the internalized bacteria, respectively.

Comparison of Low-Dose Gentamicin With Minocycline as Catheter Lock Solutions in the Prevention of Catheter-Related Bacteremia

Catheter-restricted antibiotic lock solutions were found to be effective in the prevention of catheter-related bacteremia (CRB), but insufficient data are available about the ideal agent and dose. We hypothesized that a low concentration of gentamicin would be as effective as the high doses studied in the past. In this prospective, open-labeled, randomized, clinical trial of patients on long-term hemodialysis therapy, patients were randomly assigned to administration of an antibiotic lock solution of gentamicin/citrate (4 mg/mL), minocycline/EDTA, or the control solution of heparin. Patients were followed up until the study end point of CRB was reached or a censoring event occurred. Interim data analysis was performed after 6 months to assess data safety; efficacy was noted and the study was terminated early. Sixty-two patients were enrolled into the study, evenly distributed in 3 arms, with data from 1 patient excluded from analysis. Seven of 20 patients in the heparin group (4.0 events/1,000 catheter days), 1 of 21 patients in the minocycline group (0.4 events/1,000 catheter days), and none of 20 patients in the gentamicin group developed bacteremia. Results were statistically significant by using 2-tailed Fisher exact test; heparin versus gentamicin, P = 0.008, and heparin versus minocycline, P = 0.020. Antibiotic lock solutions are superior to the standard heparin lock alone in the prevention of CRBs, and low-dose gentamicin solution has efficacy similar to that of greater concentrations used in previous studies.

Replacement of an extruded segment of radius after autoclaving and sterilising with gentamicin

A 10 year-old boy had a traumatic extrusion of 10 cm of the distal radius. The segment of bone was replaced after washing it with providine iodine solution and normal saline, autoclaving and dipping in gentamicin solution for 2 hour. At four and half year's follow-up, there was complete incorporation of the segment with almost full functional recovery. We report this case for its rarity and discuss the treatment.

Formulation, characterization and pharmacokinetic evaluation of gentamicin sulphate loaded albumin microspheres

The aim of this investigation was to prepare and evaluate microsphere formulations of gentamicin using bovine serum albumin (BSA) as a polymer matrix and glutaraldehyde as a cross-linker. Microsphere formulations of gentamicin were prepared using a spray dryer and were evaluated for product yield, encapsulation efficiency, particle size and in vitro drug release. The anti-microbial testing was performed using a modified Kirby-Bauer technique which showed that encapsulated gentamicin had an equivalent anti-microbial activity against E. coli bacteria as compared to gentamicin solution. Since it was the goal to deliver a high drug load intra-cellularly, the formulation with the least burst release profile in PBS was evaluated for its pharmacokinetic performance in rats. The in vivo pharmacokinetic evaluation on rats demonstrated increased bioavailability with microsphere formulation in comparison to the traditional solution form. The significant increase in bioavailability shall enable one to reduce the frequency of gentamicin administration and would effectively reduce the dose related side effects of gentamicin such as ototoxicity and nephrotoxicity.

Lung accumulation of niosome-entrapped gentamicin sulfate follows intravenous and intratracheal administration in rats

The organ distribution pattern of gentamicin from niosomes (25 mg/ml) w as studied in albino rats (n = 30) in comparison with free drug solution to determine the potential of the delivery system for site-specific delivery of gentamicin and also to find out the effective route of administration of this delivery system. The comparative AUC study (t = 0 to 24 h) indicated higher organ to serum AUC ratio in the case of niosomes (208.85 in the case of lung!serum. 5.10 liver/serum and 17.78 kidney!serum) against those obtained following the administration of free drug solution (25.51 in the case of lung/serum, 5.9 liver/serum and 58.1 kidney/serum). After intratracheal administration, the lung to serum concentration ratio in the case of niosome was 483.68 as against 18.23 for free drug solution which amounts to a 27-time increase in drug accumulation capacity of gentamicin sulfate niosomes to free drug solution in lungs. A significant difference in total drug concentration in lung, liver, kidney and blood serum was found between gentamicin loaded niosomes and free gentamicin solutions (P

Acute Aminoglycoside Retinal Toxicity In Vivo and In Vitro

Intentional and inadvertent intraocular administration of aminoglycosides is associated with cases of retinal toxicity. Clinical manifestations resemble a vaso-occlusive event and include edema, intraretinal hemorrhage, and nonperfusion detected by fluorescein angiogram. This study was conducted to measure the retinal function in avascular and isolated perfused retinas to separate vascular and neurologic effects of gentamicin. Enhanced understanding of the mechanism of gentamicin toxicity may lead to development of aminoglycosides that can be used to treat ophthalmic infections without retinal damage. Whole animals and isolated rabbit and rat retina preparations were used to study the dose dependence and reversibility of toxicity on the ERG, with a 1- and a 10-mg/mL solution of gentamicin. The amplitude and implicit times of the a-, b-, and c-waves were measured before, during, and after exposure to the drug. In whole-animal ERG studies, intraocular administration of gentamicin eliminated the b-wave but left the a-wave intact. The c-wave was reduced in amplitude. Histopathologic evaluation demonstrated diffuse disruption of the nerve fiber layer and the inner plexiform layers. Isolated retinal studies showed that the b-wave was reduced in amplitude in the presence of low-dose gentamicin (1 mg/mL) and completely eliminated by high-dose gentamicin (10 mg/mL). This effect was reversible for short-term exposure to gentamicin. The results indicate that the initial loss of function due to exposure to aminoglycoside antibiotics is independent of the vascular supply. Elimination of the b-wave was dose dependent and reversible, indicating that a component of gentamicin toxicity is mediated through pathways other than vascular supply. Short-term effects are reversible, suggesting a receptor-mediated process.

Transtympanic Gentamicin and Fibrin Tissue Adhesive for Treatment of Unilateral Menière’s Disease: Effects on Vestibular Function

To determine the effects of transtympanic injections, with a mixture composed of gentamicin and fibrin tissue adhesive (FTA), on vestibular function of patients with intractable unilateral Menière's disease. This was an open, prospective study. The study was performed at 2 tertiary referral centers. Twenty-six patients affected by "definite" unilateral Menière's disease, unresponsive to medical therapy for at least 6 months, were enrolled. A buffered gentamicin solution mixed with FTA was injected in the middle ear until the development of bedside vestibular hypofunction signs and/or caloric weakness in the treated ear. Vestibular function was evaluated by 3 bedside vestibular tests (observation of spontaneous nystagmus, head shaking test, and head thrust test) and by a caloric test. Tests were performed on days 10 and 30 after completion of treatment. Tests were also performed 3, 6, and 12 months from completion of the gentamicin-FTA protocol. The effects of treatment were also assessed in terms of hearing levels, control of vertigo, and disability status. In 22 of the 26 patients, only 1 gentamicin-FTA injection was necessary to obtain 1 or more signs indicating a reduction of the vestibular function in the treated ear. Four patients needed another treatment because of the persistence of their incapacitating symptoms during the follow-up. Four patients needed more than 1 injection to obtain a vestibular hypofunction. None of the patients who received 1 or 2 injections presented hearing loss in direct temporal relationship to the treatment. A mixture of gentamicin and fibrin glue makes it possible to considerably reduce the number of administrations in patients with intractable unilateral Menière's disease. Spontaneous nystagmus, post head shaking nystagmus, and a head thrust sign are the clinical signs that indicate onset or progression of unilateral vestibular hypofunction. These signs were obtained with only 1 injection in 81% of patients.

Tolerability and Efficacy of N-Chlorotaurine in Epidemic Keratoconjunctivitis—a Double-Blind, Randomized, Phase-2 Clinical Trial

The aim of this study was to assess the tolerability and efficacy of N-chlorotaurine (NCT), an endogenous antimicrobial agent, in epidemic keratoconjunctivitis. In a prospective double-blind, randomized phase 2b study, the infected eyes were treated for 7 days with eye drops containing 1% aqueous solution of N-chlorotaurine (33 subjects) or gentamicin (27 subjects, control group). Adenovirus types 3, 4, 8, 19, and 37 were detected in 39 subjects (65%), enteroviruses in 8 (13.3%), and staphylococci in 5 (8.3%). Subjective and objective symptoms were scaled and added to a subjective and objective score, respectively, on day 1 (baseline), day 4, and day 8. Analyzing the whole study population, the subjective score on day 8 was lower in the NCT group (P = 0.016), whereas there were no differences in the objective score. However, in severe infections caused by adenovirus type 8 (n = 20) both the subjective and objective score were lower in the NCT group on day 4 (P = 0.003 and 0.015, respectively), which was also true for the subjective score on day 8 (P = 0.004) in this subgroup. The frequency of subepithelial infiltrates was similar in both groups. N-chlorotaurine was well-tolerated, shortened the duration of illness, and seems to be a useful causative therapeutic approach in severe epidemic keratoconjunctivitis.

Nebulised gentamicin—suitable for childhood bronchiectasis

Nebulised antibiotic therapy is an established, safe and effective therapy for cystic fibrosis with chronic pseudomonas infection resulting in improved pulmonary function and reduced hospitalisation. Despite similar respiratory disease, this therapy has not been evaluated in children with non cystic fibrosis bronchiectasis. This study evaluates the suitability of a gentamicin solution and nebuliser combination for use in this population. Materials and methods: Four millilitres of gentamicin (80 mg) in saline delivered by a PARI LC plus ® nebuliser and PARI Turboboy N ® compressor was used. The pH, osmolarity, chloride concentration and aerosol particle size was determined. Ten children with non cystic fibrosis bronchiectasis received nebulised antibiotic and had peak gentamicin concentrations measured in sputum and serum. Pulmonary function was measured pre and post nebulisation. Results: The solution had an osmolarity of 199 mOsm/l, pH of 4.1, chloride concentration of 75 mmol/l and the aerosol a mass median aerodynamic diameter of 3.3 μm. Nebulisation was well tolerated, with no significant change in FEV1. Peak serum levels were at the threshold of detectability (0.3 mg/l). Sputum concentrations had a mean of 624 mg/g and lower 95th confidence interval 25 times the minimum inhibitory concentration for the predominant infecting organism, Haemophilus influenzae. Conclusion: Nebulisation of 80 mg of gentamicin in saline achieved bactericidal concentrations in sputum, was well tolerated and had negligible systemic absorption making it a suitable choice for this population.

Gentamicin‐loaded calcium carbonate materials: Comparison of two drug‐loading modes

Synthetic aragonite-based porous materials were drug loaded with gentamicin sulphate, an antibiotic active on Staphylococcus aureus responsible for osteomyelitis. Drug loading was accomplished by two different ways: by integration of gentamicin in material during processing or by soaking material into gentamicin solutions. We first investigated the influence of drug loading on compressive strength of materials. Results indicate that soaked materials presented the same compressive strength than unloaded materials with the same porosity. By contrast, the integration of gentamicin during processing increased significantly the compressive strength of materials. The materials drug content before elution was a least 10 times higher when gentamicin was integrated during processing comparatively to soaked materials. The study of in vitro gentamicin release showed that for materials with gentamicin integrated during material processing, high concentrations of gentamicin were released up to 8 or 12 days, against 4 days for soaked materials. The transport coefficients calculation, for the first step of release, indicated that the rate of release was higher for materials with integrated gentamicin because of the higher gentamicin content. The porosity rate influenced the rate of release for materials positively with gentamicin integrated during processing contrary to soaked materials for which a higher porosity rate allowed a deeper penetration of gentamicin during drug loading and then a slightly slower release. Results indicate that aragonite-based material with gentamicin integrated during material processing may be used either as resorbable device for release of high concentrations of gentamicin or as biomaterial for combined therapy: bone substitution and prevention or treatment of osteomyelitis.

Delivery of gentamicin to the rabbit eye by drug-loaded hydrogel iontophoresis.

To assess the corneal iontophoretic delivery of gentamicin by drug-loaded hydrogel probe, and to determine the resultant ocular disposition and elimination of the drug from the cornea and anterior chamber. Corneal iontophoresis of gentamicin sulfate was studied in healthy white rabbits by using drug-loaded disposable hydroxyethyl methacrylate (HEMA) hydrogel disk probes and a portable mini-ion device designed in the authors' laboratory. The iontophoretic treatment was performed with a current intensity of 1 mA for 60 seconds only. Three control groups were used: mock iontophoresis (no current) for 60 seconds, topical eye drops of fortified gentamicin (1.4%) every 5 minutes for 1 hour, and subconjunctival injection of 0.25 mL of 40 mg/mL gentamicin solution. The animals in the iontophoretic experimental groups were killed at predetermined time points. The gentamicin concentrations in the cornea and aqueous humor were assayed with a fluorescence polarization immunoassay. Analysis of the gentamicin eye pharmacokinetics was performed with a modeling approach. Peak gentamicin concentrations in the cornea (363.1 +/- 127.3 microg/g) and in the aqueous humor (29.4 +/- 17.4 microg/mL) were reached at 0 and 2 hours after the iontophoretic treatment, respectively. The peak gentamicin concentrations after a single iontophoresis treatment were 12 to 15 times higher than those obtained after gentamicin injection or after topical eye drop instillation, and much higher than in mock iontophoresis. The concentration versus time profile of gentamicin in the cornea and the anterior chamber after iontophoresis was appropriately described by applying a two-compartment pharmacokinetic model. A short iontophoretic treatment using gentamicin-loaded hydrogels has potential clinical value in increasing drug penetration to the anterior segments of the eye and maintaining therapeutic drug levels in the cornea for more than 8 hours.

Gentamicin release from two-solution and powder-liquid poly(methyl methacrylate)-based bone cements by using novel pH method.

The release of gentamicin as a function of time was measured for Palacos and two-solution bone cements by using a novel pH technique. The pH of an aqueous solution of gentamicin is a function of the gentamicin concentration and it decreases linearly over concentrations of 0.0-0.1 wt %. Therefore, a new, direct, and inexpensive in vitro technique was developed based on continuous readings of the pH in phosphate-buffered saline (PBS) at 37 degrees C to determine the release kinetics of gentamicin from poly(methyl methacrylate) (PMMA)-based bone cement. In addition, this method was used to compare the release profiles of Palacos R-40 bone cement with a two-solution bone cement developed in our laboratory and loaded with two different concentrations of gentamicin sulfate. Finally, the pH-based method was used to track the elution of gentamicin in both mixed and static conditions to determine the effect of mixing on the diffusion of gentamicin out of the cement. It was found that Palacos R-40 released 4.95 +/- 0.22 wt % of its gentamicin after 24 h in PBS solution. This data compares favorably with previously reported values of gentamicin elution from Palacos R-40, which ranged from 3 to 8 wt % of the total amount of incorporated gentamicin, depending on the size and the surface area of the samples. The results show that Palacos samples released 4.84 +/- 0.27 mg after 24 h, a two-solution cement loaded with an equivalent concentration of gentamicin sulfate released 3.81 +/- 0.52 mg, and two-solution cement loaded with twice the concentration of Palacos released 5.53 +/- 0.26 mg of gentamicin. A higher percentage of release was recorded from Palacos than from the two-solution bone cement, and the effect of PBS mixing conditions on the release kinetics was only significant in the early stages of release and not at 24 h. It was concluded that monitoring the pH is an effective technique to measure gentamicin release from PMMA-based bone cements in PBS solution.

Inner Ear Changes With Intracochlear Gentamicin Administration in Guinea Pigs

Transtympanic administration of gentamicin is reported to be a useful treatment for vertigo in such conditions as Meniere's disease, and determining appropriate clinical dosage of gentamicin is difficult. The authors examined the relation between gentamicin dosages and inner ear function in guinea pigs. This study is a basic science project designed to examine cochlear and vestibular function in animal models. Various concentrations of gentamicin solution were infused into the right inner ear of guinea pigs by osmotic pumps. Caloric nystagmus as a marker of vestibular function and the change in auditory brainstem response (ABR) threshold as a marker of cochlear function were observed. After 14 days of treatment, high gentamicin concentrations of 40 mg/mL caused canal paralysis and a rapid shift in ABR threshold. Animals exposed to low gentamicin concentrations of 4 mg/mL showed no obvious change in either vestibular or cochlear function. Animals exposed to moderate gentamicin concentrations of 12 mg/mL showed a moderate shift in ABR threshold and caloric malfunction. Histopathological examination revealed that after 14 days of treatment with 40 mg/mL gentamicin, severe cytoplasmic damage occurred in both vestibular and cochlear end organs. In animals treated with 12 mg/mL gentamicin, hair cells remained in the cochlear third turn and ampulla of the lateral semicircular canal. The authors established an animal model that showed the moderate damage of inner ear with moderate-dose gentamicin. The study results indicated that the appropriate administration of gentamicin could establish a stable effect on the inner ear. It may be important to select the protocol that delivers a stable dosage of gentamicin to treat patients with Meniere's disease safely and effectively.

Selective vestibular ablation by intratympanic gentamicin in patients with unilateral active ménière's disease: a prospective, double-blind, placebo-controlled, randomized clinical trial

ObjectiveTo establish the efficacy of intratympanic gentamicin treatment in patients with unilateral Ménière's disease.Material and MethodsThis was a prospective, double-blind, randomized clinical trial of intratympanic gentamicin versus intratympanic buffer solution (placebo) in patients with established active Ménière's disease in the affected ear. Outcome measures included the number of vertiginous spells, degree of sensorineural hearing loss, labyrinthine function and labyrinthine asymmetry.ResultsTopical gentamicin provided a significant reduction in the number of vertiginous spells, although a “placebo effect” was also observed. Sensorineural hearing loss did not occur in the gentamicin group, although some deterioration occurred in the placebo group.ConclusionsIntratympanic gentamicin is a safe and efficient treatment for the vertiginous spells associated with Ménière's disease. When applied early in the course of the disease, it may prevent some of the sensorineural hearing deterioration associated with it.

P.3.5 Pacemaker infection with a pocket irrigation of a gentamicin solution

P.3.5 Pacemaker infection with a pocket irrigation of a gentamicin solution

P.3.5 Pacemaker infection with a pocket irrigation of a gentamicin solution

P.3.5 Pacemaker infection with a pocket irrigation of a gentamicin solution

P.3.5 Pacemaker infection with a pocket irrigation of a gentamicin solution

P.3.5 Pacemaker infection with a pocket irrigation of a gentamicin solution

One-stage revision surgery to treat hip infected nonunion after stabilization with a sliding compression screw.

Extracapsular hip infected nonunion after stabilization with a sliding hip screw (SCS) is uncommon and a convincing treatment method has not yet been reported in the literature. Thirteen consecutive patients who sustained such a disability were treated with removal of SCS, local radical debridement, vancomycin powder with or without gentamicin solution application, re-insertion of a new SCS, and autogenous cancellous bone grafting. Postoperatively, ambulation with regulated weight bearing was encouraged as early as possible. Infectious microorganisms in 76% (10/13) of the lesion sites were oxacillin-resistant staphylococcus aureus (ORSA). Twelve patients were followed-up for at least 2 years (range, 2~6 years; median, 4 years) and all nonunions healed. The union rate was 100% (12/12) with a median union period of 4 months (range, 3~6 months). No wound infection recurred at the last follow-up. The satisfactory rate of hip function was 92% (11/12, P<0.001). We, therefore, recommend this surgical procedure to treat all patients with a similar disability because of its high success rate and low complication rate.