ABSTRACT
Arnica é o nome originalmente atribuído à espécie Arnica montana L.(Asteraceae), planta de origem Européia e utilizada em várias partes do mundo. A medicina tradicional brasileira atribui o nome de arnica também a outras espécies da família Asteraceae, especialmente algumas do gênero Lychnophora. No presente estudo foram determinadas as características físico-químicas (organoléptica, teor alcoólico, densidade, pH, porcentagem de resíduo seco) e químicas (CCD e CLAE) de tinturas preparadas com as arnicas L. pinaster e L. rupestris, em comparação com a A. montana. As amostras foram então submetidas a estudo de estabilidade, a partir da sua permanência em estufa climatizada por seis meses e em prateleira por 10 meses. Os resultados demonstraram alguma semelhança entre as tinturas de espécies de Lychnophora e a A. montana, especialmente entre seus perfis em CCD. Todas as tinturas sofreram alterações após o período de permanência na estufa, sendo o mais significante a redução no valor dos teores de resíduos secos, indicando degradação das substâncias e perda por volatilização. O conjunto das análises permitiu distinguir as tinturas de cada uma das espécies e confirmou a necessidade de determinar prazos de validade para as mesmas, devido à sua a instabilidade ao longo do tempo.
Arnica is the name attributed to Arnica montana L. (Asteraceae), an european species used in several parts of the world. The Brazilian traditional medicine also attributes the name of arnica to other species of the Asteraceae, especially some Lychnophora. In the present study physical-chemical characteristics (organoleptic, alcoholic graduation, density, pH, percentage of dry residue) and chemical (TLC and HPLC profiles) of tinctures prepared with L. rupestris, L. pinaster and A. montana has been determined. The samples had been then submitted the thermal stability testing. The results demonstrated some similarity between tinctures of the species of Lychnophora and A. montana, especially by their profiles in CCD. All tinctures altered after six months by thermal stability testing, being the most significant the reduction of percentage of dry residues, indicating degradation and loss of substances. The results allowed to distinguish tincture from the different species of arnica and confirmed their instability on the time.
ABSTRACT
Formulation excipients can frequently affect the drug analysis in pharmaceuticals yielding background interference by ultraviolet spectrophotometry. Sample separation procedures to diminish such interferences are usually recommended as sample pre-treatment, however it can be difficult to eliminate them and they can still persist. In addition, these procedures can be time consuming and laborious to perform. Excipients, like dyeing agents can also be present in a formulation and yield color to drug solution. This work reports the successful development of a derivative ultraviolet spectrophotometry for dexchlorpheniramine maleate (DPM) determination in solid dosage forms, in spite of the color imparted to tablets solution. Standard curves obtained by second order derivative ultraviolet spectrophotometry showed linearity with a correlation coefficient of 0.9999 in the concentration range of 9.75-32.5 microg ml(-1) DPM in 0.1 mol l(-1) sulfuric acid, using zero-peak (ZP) and peak-peak (PP) methods. The average relative standard deviation range was between 0.26% and 1.08% and 0.18% and 0.63% for ZP and PP methods, respectively. Application of the method in tablet samples resulted in coefficients of variation in the range of 0.83-1.40%, and 0.63-0.83% for ZP and PP methods, respectively. Recovery test percentage values obtained were between 96.95% and 105.61% for the tested tablet samples.
