41 research outputs found
Electroanalytical determination of codeine in pharmaceutical preparations
A square wave voltammetric (SWV) method and a flow injection
analysis systemwi th electrochemical detection (FIA-EC)
using a glassy carbon electrode were evaluated for the determination
of codeine in pharmaceutical preparations. The
interference of several compounds, such as acetaminophen,guaiacol, parabens, ephedrine, acetylsalicylic acid and
caffeine, that usually appear associated with codeine pharmaceutical
preparations was studied. It was verified that these
electroanalytical methods could not be used with acetaminophen
present in the formulations and that with guaiacol,
parabens or ephedrine present the use of the FIA-EC
system was impracticable. A detection limit of 5 µmol L- 1
and a linear calibration range from 40 to 140 µmol L- 1 was
obtained with the SWV method. For the flow injection
analysis procedure a linear calibration range was obtained
from 7 to 50 µmol L- 1 with a detection limit of 3 µmol L- 1
and the FIA-EC systemallowed a sampling rate of 115
samples per hour. The results obtained by the two methods,
SWV and FIA-EC, were compared with those obtained using
reference methods and demonstrated good agreement, with
relative deviations lower than 4%
Electrochemical analysis of opiates—an overview
The analysis of opiates is of vital interest in drug abuse monitoring and
research. This review presents a general overview of the electrochemical
methods used for detection and quantification of opiates in a variety of
matrices. Emphasis has been placed on the voltammetric methods used
for study and determination of morphine, codeine, and heroin. Specific
issues that need to be solved and better explained as well as future trends in the use of electrochemical methods in the examination of opiates are
also discussed
Differential cytotoxic responses of PC12 cells chronically exposed to psychostimulants or to hydrogen peroxide
Repeated abuse of stimulant drugs, cocaine and amphetamine, is associated with extraneuronal dopamine accumulation in specific brain areas. Dopamine may be cytotoxic through the generation of reactive oxygen species, namely hydrogen peroxide (H2O2), resulting from dopamine oxidative metabolism. In this work, we studied the cytotoxicity in PC12 cells (a dopaminergic neuronal model) chronically and/or acutely exposed to cocaine or amphetamine, as compared to H2O2 exposure. Chronic cocaine treatment induced sensitization to acute cocaine insult and increased cocaine-evoked accumulation of extracellular dopamine, although no changes in dihydroxyphenylacetic acid (DOPAC) levels were observed. Moreover, dopamine was depleted in cells chronically exposed to amphetamine and acute amphetamine toxicity persisted in these cells, indicating that dopamine was not involved in amphetamine cytotoxicity. PC12 cells chronically treated with H2O2 were totally resistant to acute H2O2, but not to acute cocaine or amphetamine exposure, suggesting that the toxicity induced by these stimulant drugs is unrelated to adaptation to oxidative stress. Interestingly, chronic cocaine treatment largely, but not completely, protected the cells against a H2O2 challenge, whilst a decrement in intracellular ATP was observed. This study shows that chronic treatment of PC12 cells with cocaine or H2O2 modifies the cytotoxic response to an acute exposure to these agents.http://www.sciencedirect.com/science/article/B6TCN-4HC6M2T-2/1/c10d106720c0286d647497caf01a3ae
The Debate Concerning Oral Anticoagulation: Whether to Suspend Oral Anticoagulants During Dental Treatment
A abordagem dos doentes cronicamente
anticoagulados com necessidade de
intervenções estomatológicas continua a
suscitar grande controvérsia. O aumento do
risco hemorrágico associado aos procedimentos
estomatológicos sob anticoagulação oral deve
ser pesado relativamente ao risco trombótico
acrescido causado pela interrupção da
terapêutica antitrombótica. Em cirurgia oral
minor, a mortalidade e morbilidade é superior
nos episódios tromboembólicos
comparativamente aos episódios hemorrágicos.
A informação científica disponível não apoia a
interrupção da terapêutica anticoagulante oral
para cirurgia oral minor. É intenção dos
autores propor um protocolo para a abordagem
clínica dos doentes cronicamente
anticoagulados com necessidade de tratamento
estomatológico, de forma a minimizar, quer o
risco tromboembólico, quer o risco
hemorrágico.The management of patients taking long-term
oral anticoagulants who require dental surgery
is still highly controversial. The risk of
bleeding associated with dental treatment
under oral anticoagulants must be weighed
against the risk of thromboembolism associated
with suspension of antithrombotic therapy.
Mortality and morbidity associated with
thromboembolic events are higher than those
associated with hemorrhagic events after minor
oral surgery procedures. Evidence-based
information does not support oral anticoagulant
suspension before minor oral surgery. The
authors propose a management protocol for
chronically anticoagulated patients who require
a dental procedure, to reduce both
thromboembolic risk and the risk of bleeding
New insights into the oxidation pathways of apomorphine
A detailed study of the oxidative behaviour of apomorphine in aqueous media is reported. Resorting to the synthesis
of apomorphine derivatives it was possible to identify all the anodic oxidation peaks of apomorphine, which are
related to the oxidation of the catechol and tertiary amine groups. These findings were revealed to be important since
they could lead to a better understanding of the biological interactions of apomorphine and gain insight into its
metabolic pathways. During the voltammetric studies, it was also found that apomorphine forms a complex with
borate through the catechol group leading to an increase of its oxidation potential. This property could be very useful
with regard to the stabilization of apomorphine solutions since it could drastically reduce its autoxidation
Electrochemical determination of dihydrocodeine in pharmaceuticals
Two analytical methods for the quality control of dihydrocodeine in
commercial pharmaceutical formulations have been developed and
compared with reference methods: a square wave voltammetric
(SWV) method and a flow injection analysis system with electrochemical
detection (FIA-EC). The electrochemical methods proposed were successfully applied to the determination of dihydrocodeine in
pharmaceutical tablets and in oral solutions. These methods do not
require any pretreatment of the samples, the formulation only being
dissolved in a suitable electrolyte. Validation of the methods showed
it to be precise, accurate and linear over the concentration range of
analysis. The automatic procedure based on a flow injection analysis
manifold allows a sampling rate of 115 determinations per hour