Manual or automated measuring of antipsychotics' chemical oxygen demand.

Antipsychotic (AP) drugs are becoming accumulated in terrestrial and aqueous resources due to their actual consumption. Thus, the search of methods for assessing the contamination load of these drugs is mandatory. The COD is a key parameter used for monitoring water quality upon the assessment of the effect of polluting agents on the oxygen level. Thus, the present work aims to assess the chemical oxygen demand (COD) levels of several typical and atypical antipsychotic drugs in order to obtain structure-activity relationships. It was implemented the titrimetric method with potassium dichromate as oxidant and a digestion step of 2h, followed by the measurement of remained unreduced dichromate by titration. After that, an automated sequential injection analysis (SIA) method was, also, used aiming to overcome some drawbacks of the titrimetric method. The results obtained showed a relationship between the chemical structures of antipsychotic drugs and their COD values, where the presence of aromatic rings and oxidable groups give higher COD values. It was obtained a good compliance between the results of the reference batch procedure and the SIA system, and the APs were clustered in two groups, with the values ratio between the methodologies, of 2 or 4, in the case of lower or higher COD values, respectively. The SIA methodology is capable of operating as a screening method, in any stage of a synthetic process, being also more environmentally friendly, and cost-effective. Besides, the studies presented open promising perspectives for the improvement of the effectiveness of pharmaceutical removal from the waste effluents, by assessing COD values.

Automatic methodologies to perform loading and release assays of anticancer drugs from mesoporous silicon nanoparticles.

Two automatic methodologies were developed to perform the loading and release assays of drugs from porous silicon (PSi) nanoparticles. 5-Fluorouracil (5-FU) was selected as a model drug, and different functionalized PSi nanoparticles were used. While for drug loading studies the reproducible characteristics of flow systems were explored regarding mixture and volumes taken, in the drug release flow methodology versatility in accommodating different devices around the valve were tested. Fluorescent properties of 5-FU were used with detection limit of 9 × 10-4 mg L-1 and a linear response up to 5 mg L-1 The drug loading and release procedures were optimized in sequential injection analysis (SIA) systems obtaining a huge economy regarding the time spent (4 min towards 2 h). Batch and SIA methods were tested and compared for the different behaviours of the PSi nanoparticles towards both methodologies and no noteworthy differences were obtained with Student's t-test for loading with a calculated t value of 2.04 showing the absence of statistical differences. All the results present a RSD less than 10%. So, the developed automatic methodologies are a viable alternative to load drugs and to study the release profiles from PSi nanoparticles.