Chromatographic Analysis of Aqueous Humor of Bupivacaine in Different Administration Approaches.

Different administration approaches were investigated for the selection of bupivacaine administration type and a sensitive high-performance liquid chromatographic (HPLC) method has been developed. Developed method was validated and applied for the determination of bupivacaine in rabbit aqueous humor. The separation was achieved using a XTerra, C8 (250 × 8 mm i.d., particle size 5 µm) analytical column with a mobile phase consisted of acetonitrile and sodium dihydrogen phosphate (pH = 3.0, 20 mM; 30:70, v/v). Bupivacaine detection was performed by Diode Array detector (DAD) at 220 nm. The retention times for bupivacaine is 15.886 min. HPLC-DAD method was linear in the range of 75-4000 ng/mL. The limit of detection was 25 ng/mL and the limit of quantification of bupivacaine was found to be 75 ng/mL (relative standard deviation, RSD ≤ 15%, n = 6). In intra-day and inter-day precision and accuracy analysis, the RSD was found to be in the range of 0.96 and 7.98%, the bias values were 0.64 and 3.33%. Method was carried out for three different type of bupivacaine application because of the investigation of effective drug administration. Twenty aqueous humor samples were in the range of 0.642 and 5.124 µg/mL.

Vitreous and aqueous penetration of intravitreally and orally administered moxifloxacin in an experimental rabbit model of fungal endophthalmitis.

OBJECTIVES: Moxifloxacin (MXF), is a fluoroquinolone drug thought to have some antifungal activity against Candida albicans. The aim of our study was to investigate whether intravitreally and orally administered MXF has an effective penetration into the aqueous and vitreous in an experimental model of C. albicans endophthalmitis. METHODS: Thirty-two New Zealand rabbits were included. Endophthalmitis was induced in the right eyes of the rabbits. Left eyes were used as sham controls. Group 1 received a single dose of 160 µg MXF/0.1 ml intravitreally. Group 2 received a single intravitreal dose of 160 µg MXF/0.1 ml and an oral dose of 7 mg/kg/day for 4 days. Group 3 received only an oral dose of MXF 7 mg/kg/day for 4 days. Group 4 comprised of healthy controls. On the first and fourth day of treatment aqueous and vitreous samples were aspirated to compare the penetration of MXF. KEY FINDINGS: Between the first and fourth days, in group 1, mean MXF levels in the aqueous and vitreous tended to decrease; however, in group 3, these drug levels were tended to increase. There was also a decline in the drug levels in the aqueous and vitreous of group 2. CONCLUSIONS: MXF cannot achieve sufficient penetration into the aqueous and vitreous of eyes infected with C. albicans.

Effect of ocular compression on intraocular penetration of systemic ofloxacin.

Intraocular levels of ofloxacin are documented after topical and systemic administration, but systemic administration of ofloxacin in ocular compression has not yet been studied. This study was undertaken to determine the intraocular penetration of systemic ofloxacin into aqueous and vitreous humor after the application of ocular compression in rabbit eyes. Ocular compression with the Honan balloon was applied for 30 min to the right eyes of 11 albino New Zealand white rabbits. After the application of ocular compression, 2 mg/mL of ofloxacin was administered intravenously. Samples from aqueous and vitreous humor were collected 30 min after infusion. Ofloxacin concentrations were determined through high-performance liquid chromatography. The mean aqueous level of ofloxacin was significantly higher in the compression group (2.40+/-1.00 microg/mL) than in the no-compression group (1.61+/-1.06 microg/mL) (P<.05). The mean vitreous concentrations of ofloxacin were 0.70+/-0.33 microg/mL and 0.50+/-0.18 microg/mL in the compression and no-compression groups, respectively. A significant difference was observed between vitreous levels of ofloxacin in the compression and no compression groups (P<.05). Ocular compression enhanced the penetration of ofloxacin in both aqueous and vitreous humor. The drug level in the aqueous humor was sufficient for the minimum inhibitory concentration for 90% of isolates (MIC90) to inhibit most microorganisms. Although the mean vitreous ofloxacin concentration was increased by previous ocular compression, it was not sufficiently above the MIC90 for most ocular pathogens that caused endophthalmitis.

Lens concentration of ofloxacin and lomefloxacin in an experimental endophthalmitis model.

UNLABELLED: Abstract. BACKGROUND: Bacterial endophthalmitis is a serious complication of ocular surgery and penetrating trauma. The primary causative organisms are strains of Staphylococcus aureus and Staphylococcus epidermidis. Fluoroquinolones are widely used to treat endophthalmitis. There are a few studies on the penetration of fluoroquinolones into the lens in inflamed eyes. A literature search did not identify any data regarding penetration of topical ofloxacin into the lens in normal and inflamed eyes. OBJECTIVE: The aim of this study was to determine the penetration of topical ofloxacin and lomefloxacin into the lens in a rabbit endophthalmitis model. METHODS: New Zealand white rabbits were randomly divided into 2 groups. The left eyes were infected with an intravitreal inoculation of S aureus. The right eyes were used as a noninoculated control. Groups 1 and 2 received topical ofloxacin and lomefloxacin treatment, respectively, 24 hours after the inoculation. Two drops of the study drugs were instilled in the eyes every 30 minutes for 3 hours and then every 60 minutes for 3 hours. Lens samples were obtained 30 minutes after the last ofloxacin or lomefloxacin drops were administered. High-performance liquid chromatography was used to determine the fluoroquinolone concentration. RESULTS: Ten rabbits were equally divided into the 2 treatment groups. There was no significant difference in mean (SD) lens concentrations between the control and inoculated eyes in either treatment group-ofloxacin (0.26 [0.32] µg/mL vs 0.11 [0.05] µg/mL, respectively) and lomefloxacin (0.50 [0.87] µg/mL vs 0.12 [0.08] µg/mL, respectively). CONCLUSION: The results of this small experimental study found that topical ofloxacin and lomefloxacin can accumulate in the crystalline lens after installation. Inflammation did not affect the penetration of ofloxacin or lomefloxacin into the lens.

Plasma and gingival crevicular fluid phenytoin concentrations as risk factors for gingival overgrowth.

BACKGROUND: Gingival enlargement is one of the side effects associated with the administration of phenytoin. The mechanism by which phenytoin induces gingival enlargement is not well understood. This study was conducted to investigate the relationship between plasma and gingival crevicular fluid (GCF) phenytoin concentrations and the degree of gingival overgrowth in patients with similar gingival and plaque indices and also to determine the risk factors for gingival enlargement. METHODS: Eighteen patients taking phenytoin in regular doses > or =6 months prior to the investigation participated in the study. Gingival enlargement was evaluated with two indices to score vertical and horizontal overgrowth. The gingival index (GI), plaque index (PI), gingival bleeding time index (GBTI), probing depth (PD), and clinical attachment level (CAL) were also evaluated. GCF and plasma phenytoin concentrations were determined by using high-performance liquid chromatography (HPLC). RESULTS: There was no significant difference between responders and non-responders for PD, CAL, PI, GI, and GBTI. Phenytoin was detected in all of the GCF and plasma samples using the HPLC analysis method. The mean concentration of phenytoin in GCF was significantly greater than the concentration of phenytoin in plasma. No significant difference was observed for the concentration of GCF phenytoin between responders and non-responders. However, the concentration of plasma phenytoin was significantly higher in responders than non-responders. CONCLUSION: This study showed that plasma phenytoin level appeared to be a risk factor for phenytoin-induced gingival overgrowth.

Serum and gingival crevicular fluid levels of ciprofloxacin in patients with periodontitis.

BACKGROUND: The use of antibiotics as an adjunctive therapy in the treatment of periodontal diseases is of special interest to dental practitioners. In addition to using an appropriate antibacterial agent, clinicians may find it useful to determine the local and systemic concentrations of antibiotics in infected periodontal sites to reduce the levels of bacteria. The purpose of this study was to determine the serum and gingival crevicular fluid, or GCF, concentrations of systemic ciprofloxacin in patients with periodontitis. METHODS: Ten subjects with chronic periodontitis received ciprofloxacin (500 milligrams) twice daily for five days. The authors collected GCF and serum samples immediately after administering the first dose (baseline = 0 hours) and at consecutive time points. The orifice method was used for GCF sampling, and 5 milliliters of venous blood was drawn for serum analysis. The authors used high-performance liquid chromatography to determine ciprofloxacin concentrations in GCF and serum. RESULTS: The authors found that ciprofloxacin concentrations in GCF were significantly higher than concentrations in serum at two, four, seven, 24 and 120 hours. Ciprofloxacin reached the maximum concentration, or Cmax (3.72 micrograms/ mL), in GCF two hours after the initial dose was administered. The concentration decreased to 2.06 microg/mL 24 hours after the initial administration of the drug. Serum Cmax was 2.58 microg/mL at 1.5 hours, and the concentration decreased to 0.26 microg/mL at 24 hours. CONCLUSION: The results of this clinical study show that ciprofloxacin is found in GCF and its concentration in GCF is significantly higher than that in serum. CLINICAL IMPLICATIONS: Ciprofloxacin may be useful in treating patients with periodontitis because it reaches higher concentrations in GCF than in serum.