Multi-task flow system for potentiometric analysis: its application to the determination of vitamin B6 in pharmaceuticals.

A flow set-up based on the sequential injection analysis concept was designed, aiming at increased automation and robustness of procedures related with potentiometric detection in pharmaceutical control. In this sense, programmable set-up calibration, ion-selective electrode characterization, standard addition techniques and titration procedures could be carried out without any stock solutions conventional handling or modification on the physical structure of the flow system. Evaluation of a flow-through vitamin B6 selective electrode and its application to routine analysis of pharmaceuticals were selected as models to demonstrate the system potentialities. The system ability to generate in-line calibrating solutions was verified by comparing the results with those obtained with solutions prepared by the manual procedure. The vitamin B6 determination in pharmaceutical products was carried out and in-line performed recoveries gave values within 97.4-103.5%. The system ability to perform titrations was ascertained using the precipitation reaction of vitamin B6 with tetraphenylborate. Other profitable features such as lower reagent consumption with a low effluent generation volume were also achieved.

[Myasthenia gravis: treatment with thymectomy, corticoids and plasmapheresis]. / Miastenia grave. Tratamento com timectomia, corticóide e plasmaferese.

This paper reviews a 12 year experience with myasthenia gravis management (surgical and drug therapy). A total of 27 patients were submitted to thymectomy, and 12 out of 13 showed fairly good results with this only form of therapy (15.3% with complete remission, 46.15% with marked improvement and 30.7% with moderate improvement). The other 14 need either a combination of surgery and plasmapheresis or corticosteroids with the cummulative results of: 14.8% of remission (4 out of 27), 74% of improvement (20 out of 27), 7.4% of worsening (2 out of 27) and 3.7% without change (1 out of 27). Two other patients not submitted to surgery showed either a stable state of their symptoms or a mildly worsening. Another eight patients not submitted to surgery could not be bollowed up. The authors also conclude by the validity of the use of plasmapheresis in myasthenic crises leading to a transient relief of the symptoms and suggest the use of corticosteroids as a second choice, due to their undesirable side effects and difficulty in their reduction and elimination without worsening the symptoms. Other immunosuppressive drugs could be used in cases in which those above cited therapies showed unsuitable results.