Model Analytical Development for Physical, Chemical, and Biological Characterization of Momordica charantia Vegetable Drug.

Momordica charantia is a species cultivated throughout the world and widely used in folk medicine, and its medicinal benefits are well documented, especially its pharmacological properties, including antimicrobial activities. Analytical methods have been used to aid in the characterization of compounds derived from plant drug extracts and their products. This paper developed a methodological model to evaluate the integrity of the vegetable drug M. charantia in different particle sizes, using different analytical methods. M. charantia was collected in the semiarid region of Paraíba, Brazil. The herbal medicine raw material derived from the leaves and fruits in different particle sizes was analyzed using thermoanalytical techniques as thermogravimetry (TG) and differential thermal analysis (DTA), pyrolysis coupled to gas chromatography/mass spectrometry (PYR-GC/MS), and nuclear magnetic resonance ((1)H NMR), in addition to the determination of antimicrobial activity. The different particle surface area among the samples was differentiated by the techniques. DTA and TG were used for assessing thermal and kinetic parameters and PYR-GC/MS was used for degradation products chromatographic identification through the pyrograms. The infusions obtained from the fruit and leaves of Momordica charantia presented antimicrobial activity.

Effect of corn steep liquor (CSL) and cassava wastewater (CW) on chitin and chitosan production by Cunninghamella elegans and their physicochemical characteristics and cytotoxicity.

Microbiological processes were used for chitin and chitosan production with Cunninghamella elegans UCP/WFCC 0542 grown in different concentrations of two agro-industrial wastes, corn steep liquor (CSL) and cassava wastewater (CW) established using a 2² full factorial design. The polysaccharides were extracted by alkali-acid treatment and characterized by infrared spectroscopy, viscosity, thermal analysis, elemental analysis, scanning electron microscopy and X-ray diffraction. The cytotoxicity of chitosan was evaluated for signs of vascular change on the chorioallantoic membrane of chicken eggs. The highest biomass (9.93 g/L) was obtained in trial 3 (5% CW, 8% CSL), the greatest chitin and chitosan yields were 89.39 mg/g and 57.82 mg/g, respectively, and both were obtained in trial 2 (10% CW, 4% CSL). Chitin and chitosan showed a degree of deacetylation of 40.98% and 88.24%, and a crystalline index of 35.80% and 23.82%, respectively, and chitosan showed low molecular weight (LMW 5.2 × 10³ Da). Chitin and chitosan can be considered non-irritating, due to the fact they do not promote vascular change. It was demonstrated that CSL and CW are effective renewable agroindustrial alternative substrates for the production of chitin and chitosan.

Short-term stability studies of ampicillin and cephalexin in aqueous solution and human plasma: Application of least squares method in Arrhenius equation.

A limited number of studies with application of the Arrhenius equation have been reported to drugs and biopharmaceuticals in biological fluids at frozen temperatures. This paper describes stability studies of ampicillin and cephalexin in aqueous solution and human plasma applying the Arrhenius law for determination of adequate temperature and time of storage of these drugs using appropriate statistical analysis. Stability studies of the beta-lactams in human plasma were conducted at temperatures of 20°C, 2°C, -20°C and also during four cycles of freeze-thawing. Chromatographic separation was achieved using a Shimpak C(18) column, acetonitrile as organic modifier and detection at 215nm. LC-UV-MS/MS was used to demonstrate the conversion of ampicillin into two diastereomeric forms of ampicilloic acid. Stability studies demonstrated degradation greater than 10% for ampicillin in human plasma at 20°C, 2°C and -20°C after 15h, 2.7days, 11days and for cephalexin at the same temperatures after 14h, 3.4days and 19days, respectively, and after the fourth cycle of freezing-thawing. The Arrhenius plot showed good prediction for the ideal temperature and time of storage for ampicillin (52days) and cephalexin (151days) at a temperature of -40°C, but statistical analysis (least squares method) must be applied to avoid incorrect extrapolations and estimated values out uncertainty limits.

Correlation of thermal analysis and pyrolysis coupled to GC-MS in the characterization of tacrolimus.

In recent years, thermal analysis has assumed major role in the pharmaceutical industry because it can be used to evaluate the stability both in the control of raw materials and the finished product, having employment potential in the development and characterization of new products and assessment processes. Tacrolimus (TCR) is a macrolide lactone with potent immunosuppressive activity. The purpose of this study was to characterize tacrolimus raw material using Thermal analysis and Pyrolysis coupled to Gas chromatography-Mass spectrometry (Pyr-GC-MS). It was analyzed four samples of tacrolimus named TCR A, B, C and D. Thermal analysis experiments was performed in Shimadzu equipment, under nitrogen and synthetic air atmosphere in different heating rate. Pyrolysis analysis was conducted in isothermal conditions of 300°C and 400°C coupled to GC-MS, in which the mass spectrometer was operated in scan mode to detect ions in the range of mass of m/z 25-900. The thermal studies by DSC, DTA and DSC-Photovisual showed desolvation process for all tacrolimus raw materials and TG-dynamical demonstrated two pseudo-polymorphic forms (monohydrate and sesquihydrate) of tacrolimus. It was observed good correlation between the stoichiometric mass losses of the TG-dynamical and identification of product ion in Pyr-GC/MS technique. It was possible to correlate the five pyrolytic product ions with the Ozawa kinetic analysis from the thermal decomposition of TG-dynamical. The thermal studies (DSC, DSC-Photovisual, DTA and TG-dynamical) were applied in the thermal characterization of the raw materials of tacrolimus which showed pseudo-polymorphic forms, which must be monitored by pharmaceutical industry, avoiding future problems in pharmaceutical process, chemical stability and bioavailability of the tacrolimus product.

A preformulation study of a new medicine for Chagas disease treatment: physicochemical characterization, thermal stability, and compatibility of benznidazole.

This work aimed the studies of physicochemical characterization, thermal stability, and compatibility of benznidazole (BNZ) drug by spectroscopy (NMR, IR), thermoanalytical (differential thermal analysis, differential scanning calorimetry, and thermogravimetry), and chromatographic (HPLC) techniques, beyond the analytical tools of Van't Hoff equation and Ozawa model. The compatibility study was conducted by binary mixtures (1:1, w/w) of the drug with microcrystalline cellulose 102 and 250, anhydrous lactose, and sodium starch glycolate. The physicochemical characterization confirmed data reported in scientific literature, guaranteeing authenticity of the analyzed raw material. The drug melts at 191.68°C (∆H, 119.71 J g(-1)), characteristic of a non-polymorphic raw material, and a main stage decomposition at 233.76-319.35°C (∆m, 43.32%) occurred, ending the study with almost all mass volatilized. The quantification of drug purity demonstrated a correlation of 99.63% between the data obtained by chromatographic (99.20%) and thermoanalytical technique (99.56%). The Arrhenius equation and Ozawa model showed a zero-order kinetic behavior for the drug decomposition, and a calculated provisional validity time was 2.37 years at 25°C. The compatibility study evidenced two possible chemical incompatibilities between BNZ and the tested excipients, both associated by the authors to the reaction of the BNZ's amine and a polymer carbohydrate's carbonile, being maillard reactions. The BNZ reaction with anhydrous lactose is more pronounced than with the sodium starch glycolate because the lactose has more free hydroxyl groups to undergo reduction by the drug. In this sense, this work guides the development of a new solid pharmaceutical product for Chagas disease treatment, with defined quality control parameters and physicochemical stability.

Validation of a method for determination of ampicillin in human plasma using LC-DAD.

We describe the validation data of a simple but selective chromatographic method for determination of ampicillin in human plasma using liquid chromatography-diode array detector. Blank plasma free of drugs was transferred to eppendorf's tubes and spiked with ampicillin stock solution to obtain quality control samples at 1.00, 2.50, 5.00, and 10.00 microg/mL. Extraction of ampicillin and cephalexin (internal standard) from plasma samples (250 microL) was investigated using three different methods: precipitation with perchloric acid, ultra-filtration and solid-phase extraction. Chromatographic separation was achieved using a Shimpak C(18) column (300 mm x 4.6 mm i.d.; 5 microm), and detection was done at 215 nm with a diode array UV-Vis detector. The mobile phase consisted of dihydrogen phosphate (pH 3.5)-acetonitrile (87.5:12.5, v/v) delivered at a flow rate of 1.00 mL/min. Selectivity was evaluated with different pools of human plasma. Perchloric acid precipitation showed an excellent selectivity for normal plasma. The precipitation method presented recoveries above 84.0 +/- 3.3% and 82.0 +/- 1.6%, (n = 3) for ampicillin and cephalexin, respectively. The method has a limit of detection of 0.15 microg/mL and is linear in the range of 0.30 to 100.00 microg/mL. Standardized residue analysis demonstrated normality and homocedasticity. Inter-day precision was 4.5%, and accuracy was 11.1% (n = 9). Stability studies demonstrated instability of b-lactamics in human plasma at 20 and 2 degrees C after 6 and 360 h of storage, respectively.

Validation of a capillary zone electrophoresis method for the comparative determination of etoricoxib in pharmaceutical formulations.

A CZE method was developed and validated for the analysis of etoricoxib in pharmaceutical dosage forms, using prilocaine as an internal standard. The CZE method was carried out on a fused-silica capillary (50 microm id, effective length 40 cm). The BGE consisted of 25 mM tris-phosphate solution at pH 2.5. The capillary temperature was maintained at 35 degrees C, the applied voltage was 25 kV, the injection was performed using the pressure mode at 50 mbar for 5 s, with detection at 234 nm using a photodiode array detector. The method was linear in the range of 2-150 microg/mL (r(2) = 0.9999). The specificity and stability-indicating capability were proven through the degradation studies and showing also that there was no interference of the excipients of the formulation. The accuracy was 99.49% with RSD of 0.66%. The limits of quantitation and detection were 2 and 0.58 microg/mL, respectively. Moreover, method validation demonstrated acceptable results for the precision, sensitivity, and robustness. The proposed method was successfully applied for the quantitative analysis of etoricoxib pharmaceutical formulations, and the results compared to the HPLC and LC-MS/MS methods, showing nonsignificant difference (p >0.05).

Development and validation of a method for the quantitative determination of aflatoxin contaminants in Maytenus ilicifolia by HPLC with fluorescence detection.

A method for the quantification of aflatoxins B1, G1, B2 and G2 in the medicinal herb Maytenus ilicifolia was developed and validated. The method used immunoaffinity columns for sample clean-up and HPLC with fluorescence detection without any derivatisation step. The method showed good inter-day accuracy (bias values in the range 4.5-10.7%) and precision (5-16% RSD) when applied to the determination of levels of aflatoxins ranging from 7 to 20 ppb in the plant material. The detection limits for samples of the plant material spiked with aflatoxins were 3.5 ng/g for B1 and G1 and 0.1 ng/g for B2 and G2. The method was successfully applied to commercial samples of Maytenus ilicifolia for the screening of aflatoxin contaminants.

Simultaneous determination of ranitidine and metronidazole in human plasma using high performance liquid chromatography with diode array detection.

The development and validation of a simple method for the simultaneous determination of ranitidine and metronidazole in human plasma is described. Plasma samples (250 microL) were deproteinized by precipitation with 60% perchloric acid, centrifuged and the supernatant directly injected into the HPLC. Separation was achieved in isocratic mode with a Shimpak C(18) column and a mobile phase consisting of 10mM potassium dihydrogen phosphate pH 3.5:acetonitrile (90:10, v/v) with UV detection at 315 nm. The method showed good selectivity and sensitivity. Good and consistent recovery for metronidazole and ranitidine was obtained: 96.22+/-3.52 and 95.00+/-4.50% for ranitidine (25-1000 ng/mL) and metronidazole (60-10,000 ng/mL), respectively (n=3). With this one-step sample preparation method, both ranitidine and metronidazole could be quantified simultaneously in human plasma with good precision (R.S.D.<15%) and accuracy (bias values below 15%). The limit of quantification for ranitidine and metronidazole were 20 and 40 ng/mL plasma, respectively.

Teor de bixina em quatro variedades de Bixa orellana L. cultivadas na Paraíba / Bixin content in four varieties of Bixa orellana L. grown in Paraíba

Neste trabalho foi verificado o teor de Óleos, sólidos e bixina em sementes de quatro variedades de Bixa orellana L. cultivadas na Paraíba: "Casca verde", "Casca vermelha", Bico de calango" e "Grão preto". Os melhores resultados foram obti­dos com os tipos "Casca verde" e "Casca vermelha" que apresentaram um rendimento em bixina pura, cristalina, de 1,3 e 1,1 por cento, respectivamente.

In this work it was verified the content of oils, solids and bixin in seeds of four varieties of Bixa orellana L. cultivated in Paraíba: "Casca verde", "Casca vermelha", Bico de calango" and "Grão preto". The best results were obtained with the types "Casca verde" and "Casca vermelha" that presented an yield in pure, crystalline bixina, of 1,3 and 1,1 percent, respectively.