Marcos Moisés Gonçalves

Analytical methods for vancomycin determination in biological fluids and in pharmaceuticals

Vancomycin is a glycopeptide antibiotic employed in the treatment of infections caused by certain methicillin-resistant staphylococci. It is indicated also for patients allergic to penicillin or when there is no response to penicillins or cephalosporins. The adequate vancomycin concentration levels in blood serum lies between 5 and 10 mg/L. Higher values are toxic, causing mainly nephrotoxicity and ototoxicity. Various analytical methods are described in the literature: spectrophotometric, immunologic, biologic and chromatographic methods. This paper reviews the main analytical methods for vancomycin determination in biological fluids and in pharmaceutical preparations.

Preparação e caracterização físico-química de complexos de inclusão entre anestésicos locais e hidroxipropil-beta-ciclodextrina

S(-) Bupivacaine (S(-)BVC) and Lidocaine (LDC) are widely used local anesthetics (LA). Hydroxypropyl b-cyclodextrin (HP-b-CD) is used as a drug-carrier system. The aim of this work was to characterize inclusion complexes between LA and HP-b-CD. The affinity constants determined at different pHs show favourable complexation. The release kinetics experiments showed that S(-)BVC and LDC changed the released profiles in the presence of HP-b-CD. Nuclear magnetic resonance experiments gave information about the interaction between LA and the cyclodextrin cavity. This study focused on the physicochemical characterization of drug-delivery formulations that come out as potentially new therapeutic options for pain treatment.

Caracterização do complexo de inclusão ropivacaína: β-ciclodextrina

Characteriza of the inclusion complex ropivacaine: b-cyclodextrin. Ropivacaine (RVC) is a widely used local anesthetic. The complexation of RVC with b-cyclodextrin (b-CD) is of great interest for the development of more efficient local anesthetic formulations. The present work focuses on the characterization of the RVC:b-CD complex by nuclear magnetic resonance (NMR). The stoichiometry of the complex is 1:2 RVC:b-CD. DOSY-NMR shows that the association constant is 55.5 M-1. Longitudinal relaxation time results show that RVC changes its mobility in the presence of b-CD. This study is focused on the physicochemical characterization of inclusion complexes that are potentials options for pain treatment.

In vitro evaluation of copaiba oil as a kojic acid skin enhancer

The capacity of copaiba oil to act as a skin penetration enhancer for the depigmenting agent kojic acid was evaluated using an in vitro diffusion system with static flux and shed rattlesnake skin membrane, Crotalus durissus terrificus, in saline solution at 34±2 oC as the fluid receptor. The quantities of kojic acid liberated into the fluid receptor were determined by spectrophotometry at 268 nm with intervals of one and a half hours. The membranes, pretreated with copaiba oil at 25% and 50% v/v, gave flux values of 8.0 and 12.7 µg/cm2/h, permeability values of 2.0 and 3.3 cm×10-4/h, and promotion factors of 4.1 and 3.7, respectively. These results indicate that copaiba oil, at the two concentrations studied, has the capacity to promote penetration of kojic acid.

Assessment of liquid disposal originated by uranium enrichment at Aramar Experimental Center São Paulo--Brazil.

This work presents a liquid disposal monitoring originated from uranium enrichment process at Aramar Experimental Center from 1990 to 1998. Assessment of uranium, fluorides, ammoniacal nitrogen, chemical oxygen demand, and pH measurements were made in water samples and compared with results achieved in other countries, as North America and India. The liquid disposal evaluation, generated by uranium enrichment process, showed low levels, considering most parameters established by Federal and State Legislation, aiming environmental pollution control. However, uranium levels were above the limits established by Conselho Nacional do Meio Ambiente, Environment Protection Agency and mainly by the World Health Organization.