A rapid and effective isocratic chromatographic procedure is successfully developed to determinate methotrexate (MTX) entrapment efficiency (EE) in polymeric nanocapsules using reversed-phase high-performance liquid chromatography. The method employed a RP-C(18) Shimadzu Shim-pack CLC-ODS (150 mm x 4.6 mm, 5 microm) column with mobile phase constituted by a mixture of water-acetonitrile-tetrahydrofuran (65:30:5 v/v/v; pH 3.0) at a flow rate of 0.8 mL/min. The eluate is monitored with a UV detector set at 313 nm. The parameters used in the validation process are: linearity, specificity, precision, accuracy, and limit of quantitation (LOQ). The linearity is evaluated by a calibration curve in the concentration range of 10-50 microg/mL and presented a correlation coefficient of 0.9998. The polymers (PLA or PLA-PEG), oil, and surfactants used in the nanocapsule formulation did not interfere with analysis and the recovery was quantitative. The intra and inter-day assay relative standard deviation were less than 0.72%. Results are satisfactory, and the method proved to be adequate for the determination of methotrexate in nanocapsules formulations.

Delta(9)-THC administered directly in the mPFC impaired 1-h delayed task in the radial arm maze in a manner similar to that observed for its systemic administration, suggesting that the mPFC is involved in the disruptive effects of Delta(9)-THC on spatial working memory.

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A validação é essencial para definir se uma metodologia desenvolvida está completamente adequada aos objetivos a que se destina, a fim de se obter resultados confiáveis que possam ser satisfatoriamente interpretados. Além disso, pode ser considerada um dos principais instrumentos de garantia da qualidade. Foram avaliados os parâmetros de especificidade, seletividade, limite de quantificação, linearidade, intervalo, precisão (repetibilidade e precisão intermediária) e exatidão. A linearidade apresentou coeficiente de correlação igual a 0,99975 no intervalo de 2-8 µg/mL. Os excipientes contidos na formulação não são absorvidos no comprimento de onda utilizado, não interferindo assim na análise e quantificação da substância ativa. A quantificação de piroxicam em cápsulas de gelatina através de espectrofotometria UV no comprimento de 333 nm foi aprovada em todos os parâmetros analisados, sendo portanto, devidamente validada.Palavras-chave: validação de metodologia analítica; espectrofotometria ultravioleta; piroxicam. ABSTRACTThe validation is essential to define if a developed methodology is completely adjusted to the objectives that the one is destines, in order to get trustworthy results that can be satisfactorily interpreted. Moreover, it is considered one of the main instruments of quality control. The parameters used in the validation process were: specificity, selectivity, quantification limit, linearity, range, precision (repeatability and intermediate precision) and accuracy. The linearity in the range of 2-8 µg/mL presented a correlation coefficient of 0.99975. The excipients in the formulation did not interfere with the analysis and the recovery was quantitative. The quantification of piroxicam in gelatin capsules through UV spectrophotometry in the length of 333 nm was approved in all the analyzed parameters, being therefore, duly validated.

Differential scanning calorimetry (DSC) with the support of Fourier transform infrared spectroscopy (FT-IR) was used as a screening technique for testing the compatibility of piroxicam (4-hydroxy-2-methyl-N-(2-pyridyl)-2H-1,2-benzothiazine-3carboxamide-1,1-dioxide) with various pharmaceutical excipients for solid dosage forms. Based on the results, magnesium stearate, stearic acid, and mannitol were found to show interaction with piroxicam. In conclusion, tools of DSC and FT-IR were successfully employed to evaluate the compatibility of piroxicam and selected excipients.