Non-invasive monitoring of commonly used intraocular drugs against endophthalmitis by Raman spectroscopy.
OBJECTIVE
To develop a non-contact and non-invasive method for quantification of the local concentration of certain antibiotic and antifungal drugs in the eye.


METHODS
An integrated CCD-based Raman spectroscopic system designed specifically for ophthalmic applications was used to non-invasively detect the presence of ceftazidime and amphotericin B in ocular media. Specific Raman signatures of the above named drugs were determined for various concentrations that were injected through a needle in the aqueous humor of rabbit eyes in vivo. Raman spectra were subsequently acquired by focusing an argon laser beam within the anterior chamber of the eye.


RESULTS
Compared to ocular tissue, unique spectral features of ceftazidime appeared near 1,028, 1,506, 1,586, and 1,641 cm(-1). Amphotericin B exhibited its characteristic peaks at 1,156.5 and 1,556 cm(-1). The amplitude of the spectral peak corresponding to these drugs (acquired by 1 second exposure time and 25 mW of laser power) were determined to be linearly dependent on their local concentration in the anterior chamber of the eye.


CONCLUSIONS
Raman spectroscopy may offer an effective tool to non-invasively assess the local concentration of the delivered drugs within the ocular media. This technique potentially could be used to investigate the pharmacokinetics of intraocular drugs in vivo either from a releasing implant or a direct injection.
Hosseini
K
K
The University of Texas Medical Branch, The Center for Biomedical Engineering, Galveston, Texas 77555, USA.
Jongsma
F H M
FH
Hendrikse
F
F
Motamedi
M
M
D000666:Amphotericin B / Q000493:pharmacokinetics*; D000818:Animals; D000867:Anterior Chamber; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D000935:Antifungal Agents / Q000493:pharmacokinetics*; D002442:Ceftazidime / Q000493:pharmacokinetics*; D016903:Drug Monitoring; D009877:Endophthalmitis / Q000188:drug therapy*; D011817:Rabbits; D013059:Spectrum Analysis, Raman
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D000666:Amphotericin B; D002442:Ceftazidime