HPLC-UV method development and validation for the quantification of ropinirole in new PLGA multiparticulate systems: Microspheres and nanoparticles.

A simple HPLC-UV method was developed and validated for the quantitation of RP free base encapsulated into two new multiparticulate systems (microparticles and nanoparticles), as well as for the quantification of RP hydrochloride when given as a loading dose together with the new delivery system developed. HPLC separation was achieved using a C18 Kromasil column (250 mm × 4 mm) with a mobile phase composed of acetonitrile-phosphate buffer solution (55:45, v/v) adjusted at pH 6.0 and containing 0.3% triethanolamine. Flow rate was set at 1.0 mL min(-1). The UV detector was operated at 245 nm. The method allowed for the simultaneous determination of both RP and RP-HCl. The method was linear within the range 2.5-50 µg mL(-1) for both RP and RP-HCl. The limits of detection (LOD) and quantitation (LOQ) found were 0.8 µg mL(-1) and 2.4 µg mL(-1) for RP, and 0.3 µg mL(-1) and 0.9 µg mL(-1) for RP-HCl. The method was found to be simple, rapid, specific, precise, accurate, and reproducible. The method was successfully applied to the determination of the encapsulation efficiency of RP in the multiparticulate systems developed, being 85.03 ± 3.77% and 51.12 ± 3.50%, for RP-loaded PLGA microspheres and RP-loaded PLGA nanoparticles, respectively.

[Occupational damage to the hearing-vestibular sensory system in exposure to organic solvents]. / Profesionalni uvrezhdaniia na slukhovo-vestibularnata senzora sistema pri vuzdeistvie na organichni raztvoriteli.

The studies concerning the effect of the chemical agents on the sensory systems and in particular the audio-vestibular, attain significant actuality in the conditions of rapid development of the chemical industry. Examination is performed on 60 workers at the age 30 to 55 years old, in contact with organic solvents: benzine, toluene, benzol, acetone, etc., which are above the maximum admissible concentrations (MAC). Detailed analyses are made on the anamnestic complaints of these category of workers. Purposeful studies are carried out: biochemical, fatty profile, lung test, acetone in urine, otoneurological, rheoencephalography, etc. Changes in the clinico-laboratory indices are established: leucocyte and erythrocyte test, fatty content, in the acetone level--in urine, otoneurological changes in the central links of the analysers, etc. These changes have stage character depending on the length of service and exposure.