Determination of dexamethasone in tears by capillary electrophoresis

Baeyens, Vincent; Varesio, Emmanuel; Veuthey, Jean‐Luc; Gurny, Robert

doi:10.1016/s0378-4347(96)00494-x

Cited by 50 publications

(17 citation statements)

References 20 publications

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“…Tears have limited buffering capacity, which emphasizes the importance of the pH and buffer capacity of the instilled products. 22 In order to avoid these effects in the ocular assays presented here, test formulations were adjusted to tear fluid pH (7.4) using 0.1 M NaOH.…”

Section: Entrapment Efficiencymentioning

confidence: 99%

Role of hydroxypropyl-β-cyclodextrin on freeze-dried and gamma-irradiated PLGA and PLGA–PEG diblock copolymer nanospheres for ophthalmic flurbiprofen delivery

Vega¹,

Egea²,

Calpena³

et al. 2012

IJN

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Poly(D,L-lactide-co-glycolide) and poly(D,L-lactide-co-glycolide) with poly(ethylene glycol) nanospheres (NSs) incorporating flurbiprofen (FB) were freeze-dried with several cryoprotective agents and sterilized by γ-irradiation. Only when 5.0% (w/v) hydroxypropyl-β-cyclodextrin (HPβCD) was used, a complete resuspension by manual shaking and almost identical particle size of the NSs was obtained after freeze-drying. In vitro drug release and ex vivo corneal permeation of NSs with and without HPβCD were evaluated. The presence of HPβCD resulted in a reduction of burst effect, providing a more sustained release of the drug. A significant decrease in the FB transcorneal permeation of NSs containing HPβCD was obtained, related to the slower diffusion of FB observed in the in vitro results. The uptake mechanism of the NSs was examined by confocal microscopy, suggesting that NSs penetrate corneal epithelium through a transcellular pathway. Ocular tolerance was assessed in vitro and in vivo by the Eytex™ and Draize test, respectively. Long-term stability studies revealed that γ-irradiated NSs stored as freeze-dried powders maintained their initial characteristics. Stability studies of the resuspended NSs after 3 months of storage in the aqueous form showed that NSs were stable at 4°C, while formulations stored at 25°C and 40°C increased their initial particle size.

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Section: Entrapment Efficiencymentioning

confidence: 99%

Role of hydroxypropyl-β-cyclodextrin on freeze-dried and gamma-irradiated PLGA and PLGA–PEG diblock copolymer nanospheres for ophthalmic flurbiprofen delivery

Vega¹,

Egea²,

Calpena³

et al. 2012

IJN

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“…Determination of ofloxacin in tears was carried out on a HP 3D CE system (Hewlett-Packard, Wilmington, DE), as described earlier 7 . The system consists of a capillary electrophoresis unit equipped with a diode array detector (DAD), an autosampler, and a highvelocity air-cooled capillary cartridge.…”

Section: Determination Of Ofloxacin Concentration In Tearsmentioning

confidence: 99%

Delivery of antibiotics to the eye using a positively charged polysaccharide as vehicle

Felt

Gurny

Baeyens³

2001

AAPS PharmSci

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The positively charged polysaccharide chitosan is able to increase precorneal residence time of ophthalmic formulations containing active compounds when compared with simple aqueous solutions. The purpose of the study was to evaluate tear concentration of tobramycin and ofloxacin after topical application of chitosan-based formulations containing 0.3% wt/vol of antibiotic and to compare them with 2 commercial solutions: Tobrex® and Floxal®, respectively. The influence of the molecular weight, deacetylation degree, and concentration of 4 different samples of chitosan on pharmacokinetic parameters (area under the curve values [AUC eff ] and time of efficacy [t eff ]) of tobramycin and ofloxacin in tears was investigated over time. It was demonstrated that the 2 chitosan products of high molecular weight (1350 and 1930 kd) and low deacetylation degree (50%) significantly increased antibiotic availability when compared to the controls, with AUC eff showing a 2-to 3-fold improvement. The time of efficacy of ofloxacin was significantly increased from about 25 minutes to 46 minutes by the chitosan of higher Mw (1930 kd) at a concentration of 0.5% wt/vol, whereas a similar performance was achieved by a chitosan of low Mw (580 kd) at a concentration of 1.5% wt/vol in the case of tobramycin.

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“…Other methods were reported for the corticosteroids, such as spectrophotometry [11,12], HPLC [13][14][15][16], and capillary electrophoresis [17,18].…”

Section: Introductionmentioning

confidence: 99%

Comparative study of RP-HPLC versus TLC-spectrodensitometric methods applied for binary mixtures of fluoroquinolones and corticosteroids

El-Gizawy¹,

Hassan²,

Lotfy³

et al. 2014

Acta Chromatographica

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Summary.Reversed phase high-performance liquid chromatography (RP-HPLC) and thin-layer chromatography (TLC)-spectrodensitometric methods have been developed and validated for the separation and quantitation of two binary mixtures: Ofloxacin (OFX) and dexamethasone (DXM) in eye preparation; ciprofloxacin hydrochloride (CIP) and hydrocortisone (HYD) in ear preparation. The linearity ranges of RP-HPLC methods were found to be (2.5-45 μg mL −1 ) for OFX, (2.5-50 μg mL −1 ) for DXM and (1-8 μg mL −1 ) for both CIP and HYD. The percentage recoveries/relative standard deviation (RSD) were found to be 100.36/1.38, 100.13/1.49, 99.98/0.61 and 100.28/1.27, respectively. The linearity ranges of TLC-spectrodensitometric methods were found to be (0.5-2 μg band −1 ), (0.5-3.5 μg band −1 ), (0.2-1.6 μg band −1 ), and (0.6-2 μg band −1 ) for OFX, DXM, CIP, and HYD, respectively. The percentage recoveries/RSD were found to be 99.98/1.06, 99.93/1.18, 99.74/1.27, and 99.94/1.54, respectively. A comparative study was conducted to show the advantages of the proposed methods which showed that the TLC-spectrodensitometric methods were simpler, more sensitive, and economic, while RP-HPLC methods were more precise and robust. The methods were validated in compliance with the ICH guidelines and were successfully applied for determination of the selected drugs in their laboratory-prepared mixtures and commercial dosage forms.

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Determination of dexamethasone in tears by capillary electrophoresis

Cited by 50 publications

References 20 publications

Role of hydroxypropyl-β-cyclodextrin on freeze-dried and gamma-irradiated PLGA and PLGA–PEG diblock copolymer nanospheres for ophthalmic flurbiprofen delivery

Role of hydroxypropyl-β-cyclodextrin on freeze-dried and gamma-irradiated PLGA and PLGA–PEG diblock copolymer nanospheres for ophthalmic flurbiprofen delivery

Delivery of antibiotics to the eye using a positively charged polysaccharide as vehicle

Comparative study of RP-HPLC versus TLC-spectrodensitometric methods applied for binary mixtures of fluoroquinolones and corticosteroids

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Determination of dexamethasone in tears by capillary electrophoresis

Cited by 50 publications

References 20 publications

Role of hydroxypropyl-&beta;-cyclodextrin on freeze-dried and gamma-irradiated PLGA and PLGA&ndash;PEG diblock copolymer nanospheres for ophthalmic flurbiprofen delivery

Role of hydroxypropyl-&beta;-cyclodextrin on freeze-dried and gamma-irradiated PLGA and PLGA&ndash;PEG diblock copolymer nanospheres for ophthalmic flurbiprofen delivery

Delivery of antibiotics to the eye using a positively charged polysaccharide as vehicle

Comparative study of RP-HPLC versus TLC-spectrodensitometric methods applied for binary mixtures of fluoroquinolones and corticosteroids

Contact Info

Product

Resources

About

Role of hydroxypropyl-β-cyclodextrin on freeze-dried and gamma-irradiated PLGA and PLGA–PEG diblock copolymer nanospheres for ophthalmic flurbiprofen delivery

Role of hydroxypropyl-β-cyclodextrin on freeze-dried and gamma-irradiated PLGA and PLGA–PEG diblock copolymer nanospheres for ophthalmic flurbiprofen delivery