Purpose: Objective of the study was a direct evaluation in rabbits of the precorneal residence time (PRT) of drugs based on UV and fluorescence diffuse reflectance spectroscopy, for the first time in qualitative fashion. Methods: We evaluated the PRT of timolol and ofloxacin in aqueous formulations with or without sodium hyaluronate (SH) as viscosizing agent. Rayleigh diffuse reflectance {timolol) and fluorescence diffuse reflectance (ofloxacin) were performed after instillation of 25 jjl of the formulations in the conjunctival sac of rabbits. Results: Our apparatus supplies qualitative information by recording all spectra in both UV and fluorescence mode. In the UV studies the SH viscosized timolol formulation cleared significantly more slowly (p<0.05) than reference water preparation (PRT 5001150 and 200±70 sec, respectively). The same behaviour was observed in the fluorescence studies where the SH viscosized ofloxacin formulation showed a greater PRT (4501170 sec) than the reference water solution (178+55 sec). Conclusion: The diffuse reflectance spectroscopy allowed to detect the PRT of ophthalmic drugs after topical instillation in rabbits for the first time in a direct and qualitative manner.
Direct evaluation of precorneal residence time of drugs by diffuse reflectance spectroscopv
Spadaro A.;Bucolo C.;Cro M.;
1997-01-01
Abstract
Purpose: Objective of the study was a direct evaluation in rabbits of the precorneal residence time (PRT) of drugs based on UV and fluorescence diffuse reflectance spectroscopy, for the first time in qualitative fashion. Methods: We evaluated the PRT of timolol and ofloxacin in aqueous formulations with or without sodium hyaluronate (SH) as viscosizing agent. Rayleigh diffuse reflectance {timolol) and fluorescence diffuse reflectance (ofloxacin) were performed after instillation of 25 jjl of the formulations in the conjunctival sac of rabbits. Results: Our apparatus supplies qualitative information by recording all spectra in both UV and fluorescence mode. In the UV studies the SH viscosized timolol formulation cleared significantly more slowly (p<0.05) than reference water preparation (PRT 5001150 and 200±70 sec, respectively). The same behaviour was observed in the fluorescence studies where the SH viscosized ofloxacin formulation showed a greater PRT (4501170 sec) than the reference water solution (178+55 sec). Conclusion: The diffuse reflectance spectroscopy allowed to detect the PRT of ophthalmic drugs after topical instillation in rabbits for the first time in a direct and qualitative manner.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
