The factors selected as an independent variable to study included antioxidant dinatri EDTA and viscosity enhancers PVP. Value of pH and percent of remained tobramycine contents after 3 months with ageing at 500C compared with primary tobramycine were selected as a dependent variable. Experimental model was designed according to model of quadratic equation including 9 formulas. The relationship between independent variables X and dependent variables Y conformed to quadratic regressive equation. Base on preliminary formulas selected, Modde 5.0 software was used to trace experimentally and deal with the results. Optimal formula of tobramycine eye drop 0.3% had stableness over 3 months at 50oC and over 12 months at normal condition
Ophthalmic Solutions ; Tobramycin

Study on some influencing factors such as buffer, antioxidant substances to build primary formulation of tobramycin eye drops with stability over 12 months. Result: temperature and light have much influence to the stability of tobramycin and pH contents of eye drops solution. High temperature impacts clearly to the decrease of tobramycin pH and contents. The solution was stable with borate buffer more than phosphate and citrate buffer. Product samples without antioxidant substances have low remained tobramycin contents, about 70% after three months ageing. Dinatri EDTA, natri bisulfit and dinatri EDTA-natri bisulfit combination have significant effect to the stable of tobramycin content. However, dinatri EDTA choice compared with dinatri EDTA-natri bisulfit combination is the same because of dinatri EDTA effect. Dinatri EDTA has better effect to the stable of pH and increase anti-bacteria effect of benzalkonium chloride
Ophthalmic Solutions ; Tobramycin ; Drug Stability

To evaluate the efficacy of polygexamethylene biguanide(PHMB) in Pseudomonas aeruginosa(P. aeruginosa) keratites model, 10microliter of P. aeruginosa bacterial suspension(1x103 colony-forming unit(cfu)/ml) was injected intrastromally into rabbit corneas. Eighteen rabbits(36 eyes) were divided into three treatment groups: balanced salt solution(BSS) group(N=18 eyes). PHMB(0.02%, 200microliter/ml) group(n=9 eyes), tobramycin(14microliter/ml) group(n=9 eyes). Topical antibiotic drops were given hourly from 12 hours after inoculation. A subconjunctival infection was every 24 hours during the first 72 hours. The Severity of keratitis was scored in basked fashion every 8 hours. Corneal buttons were excised and homogenized at the end of the study to determine the viable bacterial counts. In P. aeruginosa keratitis model, tobramycin was statistically more efficacious than PHMB, according the clinical scores at 58 hours(9.9 vs. 15.1, P<0.0001) and log10 cfu(0.54+/-0.21 vs. 4.87+/-1.07. P<0.0001). No differences were found between the PHMB and BSS groups in either clinical scores or bacterial counts. PHMB appears to be ineffective against P. aeruginosa in experimental keratitis model of rabbit.
Bacterial Load ; Cornea ; Keratitis* ; Pseudomonas aeruginosa* ; Pseudomonas* ; Tobramycin

Green nail syndrome (chromonychia) is a nail disorder characterized by onycholysis and green-black discoloration of the nail bed. This condition is often associated with chronic paronychia. Pseudomonas aeruginosa is the most commonly identified organism in cultures from the affected area. Despite the various treatment options available, removal of the nail is still necessary in many cases. A 35-year-old man presented with dark-greenish discoloration of the nail plate and onycholysis on the left thumbnail. He had been treated with oral antifungal and antibiotic agents for several months; however, the lesion showed no improvement. The diagnosis of green nail syndrome was established after a positive bacterial culture, and on the basis of the antibiotic sensitivity test result, tobramycin eye drop (Tobrex(R)) was then prescribed. Three weeks later, the nail discoloration almost vanished but the onycholysis remained. Herein, we recommend the application of tobramycin eye drop as an easy and safe treatment option for green nail syndrome.
Adult ; Diagnosis ; Humans ; Onycholysis ; Paronychia ; Pseudomonas aeruginosa ; Tobramycin*

To determine whether liposome-encapsulated tobramycin is less toxic than commercial tobramycin and the threshold dose of liposome-encapsulated tobramycin required to produce toxic reactions when it was injected intravitreally in rabbit, we used liposome-encapsulated tobramycin, tobramycin in PBS, mixture of tobramycin and liposome-encapsulated saline, liposome-encapsulated saline and normal saline respectively. After those were injected, we examined the histologic findings and the functional changes of the retina. The final results are summarized as follows; 1. When tobramycin was injected intravitreally alone, there was no toxic reaction of the retina histologically and functionally with dosage 500 micro gram of commercial tobramycin, but dosage more than 750 micro gram produced toxic reaction. 2. When liposome-encapsulated tobramycin was injected intravitreally, there was toxic reaction of the retina histologically and functionally with dosage 1500 micro gram of tobramycin. 3. When a mixture of tobramycin and liposome-encapsulated saline was injected intravitreally, there was similar toxic reaction as tobramycin used alone with dosage more than 750 micro gram of tobramycin. Liposome-encapsulated saline and normal saline did not produce toxic reaction. The above results indicate that liposome encapsulation markedly reduces the ocular toxicity of tobramycin and that as mnch as dosage 1000 micro gram of liposome-encapsulated tobramycin may be tolerated by the intravitreal route in the rabbit eye. Therefore, the results of this study offer some hope that we may use the method of intravitreal injection of liposome-encapsulated tobramycin safely and effeciently for the treatment of bacterial endophthalmitis in near future.
Endophthalmitis ; Hope ; Intravitreal Injections ; Liposomes ; Rabbits* ; Retina* ; Tobramycin*

Bacterial keratitis is a common ophthalmic disease. Recently, topical and subconjunctival therapy were equally effective in reducing the number of viable bacteria in experimental corneal ulcers. Subconjunctival injection produced high but transient concentrations followed by persistent low levels. In contrast, eyedrops produced moderate but sustained concentrations throughout the treatment period. Liposomes are small, biodegradable lipid vesicles with an aqueous core. Incorporation of drugs into liposomes provides a convenient way to retard their release from a relatively inert depot without changing the intrinsic characteristics of the agents.
Bacteria ; Cornea* ; Keratitis ; Liposomes* ; Ophthalmic Solutions ; Rabbits* ; Sclera* ; Tobramycin* ; Ulcer

The authers investigated the effct of liposome encapsulation on the pharmacokinetics of tobramycin after subconjuctival in jnjection in rabbits. Tobramycin was encapsulated into neutral liposomes of phosphatidylcholine and cholesterol. The final liposomal suspension contained tobramycin, 5mg/ml. One of the each rabbit received a subconjunctival injection(2.5mg/0.5ml) of liposome-encapsulated tobramycin or tobramycin alone. Tobramycin levels in the sclera measured 3 and 24 hours after injection were marked higher with the liposome-encapsulated drug than with the another preperation. The difference between liposomeencapsulated drug and the another preperation was not significant for cornea.
Cholesterol ; Cornea* ; Liposomes ; Pharmacokinetics ; Phosphatidylcholines ; Rabbits* ; Sclera* ; Tobramycin*

BACKGROUND: Acinetobacter baumannii has been reported as a major cause of nosocomial infections with increasing frequency. Recently, the emergence of carbapenem-resistant strains has become a major problem in treatment. The use of nontraditional agents such as colistin and a combination therapy have been tried. The purpose of this study was to evaluate the activity of antimicrobial combinations against multidrug-resistant (MDR) A. baumannii. METHODS: Twenty-nine strains of MDR A. baumannii, either resistant or intermediate to imipenem, were collected from February 2003 to February 2004. Minimum inhibitory concentrations (MICs) were determined by the agar dilution method. The checkerboard method was used to assess the activity of ampicillin-sulbactam in combination with amikacin, tobramycin or meropenem and colistin in combination with ceftazidime, meropenem, or rifampin. RESULTS: The MIC90 of ceftazidime and cefepime were 2, 048 g/mL and 512 g/mL, respectively, while the MIC90 of colistin was 0.5 g/mL. The antimicrobial combinations that showed an additive effect for one or two strains were colistin with rifampin or ceftazidime and ampicillin-sulbactam with tobramycin or meropenem. Other antimicrobial combinations showed indifferent effects against most strains. There were no synergistic or antagonistic combinations. CONCLUSIONS: These data suggested that colistin may be an alternative drug for MDR A. baumannii. For the effective treatment of patients infected with these resistant strains, further studies are needed to evaluate antimicrobial combinations against a large number of heterogeneous isolates, and these studies must be followed by clinical trials.
Acinetobacter baumannii* ; Agar ; Amikacin ; Ceftazidime ; Colistin ; Cross Infection ; Humans ; Imipenem ; Microbial Sensitivity Tests ; Rifampin ; Tobramycin

AIMTo study the dissociation pathways of aminoglycoside antibiotics.

METHODSIn positive mode, eight aminoglycoside antibiotics were elucidated by use of electrospray ion trap mass spectrometry in the multi-stage MS full scan mode.

RESULTSIt was demonstrated that the eight aminoglycoside antibiotics gave abundant product ions at m/z 322 (gentamicin, micronomicin and sisomicin), m/z 350 (etimicin, netilmicin and vetilmicin) and m/z 324 (kanamycin and tobramycin) by loss of the C-ring (amino-alpha-D-glucopyranose) in MS2 full scan mode. In MS3 full scan mode, the prominent fragmentation ions at m/z 163 as well as m/z 191 were formed from the fragmentation ions at m/z 322, m/z 350 and m/z 324 by loss of the A-ring (amino-alpha-D-glucopyranose), separately, while the characteristic fragmentation ions at m/z 160 as well as m/z 162 were formed from m/z 322, m/z 350 and m/z 324 by loss of the B-ring (2-deoxy-D-streptamine), separately.

CONCLUSIONThe structural information was obtained via collision-activated dissociation and these characteristics are applicable to the structural elucidation and quantitative analysis of aminoglycoside compounds.

Aminoglycosides ; analysis ; chemistry ; Gentamicins ; analysis ; chemistry ; Molecular Structure ; Spectrometry, Mass, Electrospray Ionization ; methods ; Tobramycin ; analysis ; chemistry

A bacterial study of the conjunctival sac of 115 patients with an anophthalmic eye has compared the kinds of normal flora in the conjunctival sac of normal and anophthalmic eyes and investigated the susceptibility of the isolated bacteria to various antibiotics. Detection rate of bacteria were 35.7% and 69.6% in normal and anophthalmic eyes, respectively. In normal eyes S. epidermidis(40.4%) were isolated more frequently than S. aureus(21.3%), but the detection rate for each bacteria in anophthalmic eyes showed no significant differences. The incidence rate in kinds of bacterial flora in both conjunctival sacs of a person who has one anophthalmic eye was 37.5%, lower than that of a person with normal eyes(71.4% to 96.5%). Bacteria isolated from normal and anophthalmic conjunctiva were similarly sensitive to amikacin, cefazolin, erythromycin, oxacillin. and tobramycin and were resistant to ampicillin and penicllin.
Amikacin ; Ampicillin ; Anophthalmos ; Anti-Bacterial Agents ; Bacteria ; Cefazolin ; Conjunctiva ; Erythromycin ; Eye ; Humans ; Incidence ; Oxacillin ; Tobramycin