Greenness Assessment and Validation of HPLC Method for Simultaneous Determination of Resveratrol and Vitamin E in Dietary Supplements.

BACKGROUND: There is an increasing interest in the use of a combination of trans-resveratrol and vitamin E in dietary supplements. Determination of the content of both components is essential for confirmation of the quality of the product. OBJECTIVE: To establish the applicability and ensure the greenness of the previously developed high-throughput HPLC/UV method for the simultaneous determination of trans-resveratrol and alpha-tocopherol acetate (vitamin E) in dietary supplements. METHOD: Separation was performed on RP C8 Select B chromatographic column, using acetonitrile and water in the mobile phase, with gradient elution. Full method validation was performed in accordance with ICH Q2(R1). The greenness of the method was assessed using the analytical eco-scale (AES) methodology and the analytical greenness metric (AGREE). RESULTS: The method is selective, linear, precise, and accurate over defined concentration ranges (185-369 µg/mL of trans-resveratrol and 37-75 µg/mL of alpha-tocopherol acetate), and it has a suitable sensitivity (limits of detection and quantification are 7.7 and 23.3 µg/mL for resveratrol and 2.6 and 7.8 µg/mL for tocopherol acetate, respectively). The obtained analytical eco-scale score of 77 and the pale green AGREE pictogram with an overall score of 0.61 confirm the method's greenness. CONCLUSIONS: The sensitivity and selectivity of the method, its short analysis time (7 min), the low negative environmental impact, and the simple sample preparation make the method readily applicable to inline quality control procedures. HIGHLIGHTS: A method for simultaneously analyzing vitamin E and resveratrol in dietary supplements is presented. The method is rapid, includes a simple sample preparation procedure, and has a low environmental impact.

Development and validation of a reversed-phase HPLC method for determination of alkaloids from Papaver somniferum L. (Papaveraceae).

An HPLC method for the separation of six target alkaloids from Papaver somniferum L. (morphine, codeine, oripavine, thebaine, papaverine, and noscapine) was developed, optimized, and validated. The chromatographic behavior of these alkaloids was investigated using a reversed-phase chromatography at acidic and alkaline pH. The effects of ion-pairing agents, pH value of the mobile phase, concentration of the buffer components, mobile phase organic modifier, and column temperature were studied. Regardless of the large differences in their pKa values, all alkaloids were separated within a close retention window, and good peak shape was achieved for each of the six alkaloids. The proposed method has adequate selectivity, linearity, accuracy, precision, and reproducibility and is applicable for poppy straw.

Development and Validation of Discriminative Dissolution Method for Metformin Immediate-Release Film-Coated Tablets.

The purpose of this study was to develop and validate a discriminative dissolution method for the metformin film-coated tablet with immediate release of the active substance that belongs to class III of the Biopharmaceutical Classification System (BCS). Different conditions such as type of dissolution medium, volume of dissolution medium, rotation speed, apparatus, and filter suitability were evaluated. The most discriminative release profile for the metformin film-coated tablet was accomplished by using Apparatus II (paddle) and 1000 mL of phosphate buffer pH 6.8 as the dissolution medium and maintained on 37 ± 0.5°C with a rotation speed of 75 rpm. The quantification of the released active substance was performed by UV/Vis spectrophotometry, at 232 nm. Acceptance criteria for not less than 75% (Q) of the labeled content for 45 minutes were set. The dissolution method was validated according to the current international guidelines using the following parameters: specificity, accuracy, precision, linearity, robustness, and stability of the solutions, found to be meeting the predetermined acceptance criteria. A developed dissolution method has discriminatory power to reflect the characteristics of the medicinal product and is able to distinguish any changes related to quantitative formulation and can be also applied for routine batch testing.

Immunoproteomic identification of antigenic candidate Campylobacter jejuni and human peripheral nerve proteins involved in Guillain-Barré syndrome.

Immunoproteomics is become a potent methodology used for identifying immunoreactive proteins. In this study, an immunoproteomic approach based on 2-dimensional gel electrophoresis (2D-PAGE) and immunoblotting combined with high resolution mass spectrometry (MS) was used to identify immunoreactive proteins that might be involved in mechanisms of Guillain-Barré syndrome (GBS) development, regardless of their potential reciprocal molecular mimicry. Proteins isolated from C. jejuni and human peripheral nerve tissue (HPN) were separated with 2D SDS-PAGE and subjected to western blotting using serum samples from GBS patients. The peptides generated after proteolysis of the immunoreactive proteins were submitted to nanoflow-high performance liquid chromatography-nano electrospray ionization coupled to high resolution mass spectrometry (nHPLC-nESI-MS and MS/MS) followed by SEQUESTdata analysis for proteins identification. In C. jejuni, immunoreactivity was found for GroEL and DnaK, structural proteins (MOMP), key enzymatic proteins necessary for the microbial proliferation (adenylate kinase, enolase, inorganic pyrophosphatase and aspartate ammonia-lyase), and antioxidant enzymes (alkyl hydroperoxide reductase-AhpC and DNA protection during starvation protein - DNA protection factor against Fe2+-mediated oxidative stress). HPN immunoreactive proteins identified were heat shock proteins (HSP), intermediate filaments (vimentin and desmin), and other proteins and enzymes such as troponin/tropomyosin complex and ATP synthase subunit beta and the keratan sulfate proteoglycan lumican. The targeting of vimentin and desmin, suggested that the neuronal autoimmune damage is specifically directed to intermediate neuronal (vimentin) and neuromuscular IF, probably localized nearby cell surface, affording increased accessibility to autoantibodies. These findings suggest that the post-infectious development of GBS may be also associated to additional concomitant immune factors that lead to nerve damage generated by auto-immune trigger(s) different from molecular mimicry.

Evaluation of Correlation Between the Pharmacogenetic Profiles of Risperidone Treated Psychiatry Patients with Plasma and Urine Concentration of Risperidone and its Active Moiety 9-OH Risperidone Determined with Optimized Bioanalytical LC Method.

Atypical antipsychotic risperidone is widely used first-line monotherapy in schizophrenia and combined therapy in bipolar disorders. Therapeutic plasma concentrations of risperidone and its active moiety are directly influenced by genetic variations in metabolic CYP450 enzymes (CYP2D6 and CYP3A4/5) and transporter (ABCB1) protein and additional environmental factors. Since active metabolite 9-OH risperidone has a greater percentage of the pharmacologically active fraction and is equipotent to the parent drug risperidone, it is assumed that it contributes significantly to therapeutic and adverse effects. Unpredictable dose/concentration ratio, narrow therapeutic index, number of interactions, along with serious adverse reactions (ADR), raises the need for individualization of risperidone treatment and establishing of good therapeutic regime using TDM. A simple and reliable validated bioanalytical liquide-liquide extraction HPLC/UV method was applied for the simultaneous determination of risperidone and its active metabolite, 9-OH risperidone, in human plasma and urine of 52 hospitalized schizophrenia/bipolar disorder patients treated with risperidone as monotherapy and in polytherapy. All the patients were previously genotyped for CYP2D6 (EM=30, EM/IM=14, IM=4 IM/PM=1 and PM=3) and ABCB1 using Real-Time PCR methods with TaqMan SNP genotyping suitable assays according to the guidelines of the manufacturer (Life Technologies, USA).The influence of CYP2D6 phenotype on metabolic ratio MR (Ris/9-OHRis) in plasma (p=0.012) and in urine (p=0.048) was confirmed. Statistically significant correlation (R2=55.53%, Rho=0.844, p<0,0001) for MR in both plasma and urine indicates that urine may be utilized as appropriate media for initial CYP2D6 phenotype identification and selection of patients on risperidone treatment with high risk for ADR.

Optimization of HS-GC-FID-MS Method for Residual Solvent Profiling in Active Pharmaceutical Ingredients Using DoE.

Within this research, a headspace (HS) gas chromatography-flame ionization detector-mass spectrometry method was developed for profiling of residual solvents (RSs) in active pharmaceutical ingredients (APIs). Design of experiment was used for optimization of sample preparation, as well as for robustness testing of the method. HS equilibration temperature and dilution medium were detected as parameters with greater impact on the sensitivity, compared with the time used for equilibration of the samples. Regardless of the sample solubility, the use of water for sample preparation was found to be crucial for better sensitivity. The use of a well-designed strategy for method development and robustness testing, additional level of identification confidence, as well as use of internal standard provided a strong and reliable analytical tool for API fingerprinting, thus enabling the authentication of the substance based on the RS profile.

Guillain Barré syndrome (GBS): new insights in the molecular mimicry between C. jejuni and human peripheral nerve (HPN) proteins.

Profile and immunoreactivity of proteins from HPN tissue, and from Campylobacter jejuni (O:19) were investigated. Proteins were extracted, separated by SDS-PAGE, their cross reactivity monitored by Western blotting, and identified by nHPLC-nESI-HRMS analysis. Proteins from C. jejuni, at Mw ~70 KDa were chaperone/co-chaperone proteins (GroEL, DnaK and HtpG). In the corresponding HPN band were serum albumin, neurofilament light peptide, cytoskeletal keratins and one HSP 70 and one HSP60. These chaperones reciprocally share high primary sequence homology and conservation of their known epitopes. These findings suggest that HSP chaperones may be suitable candidates involved in the molecular mimicry triggering GBS.

Antibodies to Glycoproteins Shared by Human Peripheral Nerve and Campylobacter jejuni in Patients with Multifocal Motor Neuropathy.

We have tested serum samples from 24 patients with multifocal motor neuropathy (MMN) for reactivity to ganglioside GM1 and to Gal( ß 1-3)GalNAc-bearing glycoproteins isolated from human peripheral nerve and from Campylobacter jejuni (Cj) serotype O:19. IgM anti-GM1 antibodies were detected by ELISA in 11 patients (45.8%) with MMN and in only one subject (4%) from the control group. Western blots showed positive reactivity of sera from 6 patients (25%) with MMN to several Gal( ß 1-3)GalNAc-bearing glycoproteins from human peripheral nerve and from Cj O:19 isolates. Sera from three patients (12.5%) with MMN showed positively reactive bands with similar electrophoretic mobility in all isolates (60-62 kDa, 48-51 kDa, 42 kDa, and 38 kDa). All six patients showed positive reactivity to 48-52 kDa protein isolated from human peripheral nerve. Increased titer of IgG antibodies to 60-62 kDa protein isolated from Cj O:19 associated with Guillain-Barré syndrome was detected in three patients, and their serum showed also IgG positive reactivity to peripheral nerve antigen with the same electrophoretic mobility. One of these patients had a previous history of Cj infection which suggests the possibility that Cj may be also involved in the pathogenesis of MMN.

Immunoreactivity of glycoproteins isolated from human peripheral nerve and Campylobacter jejuni (O:19).

OBJECTIVE: Antibodies to ganglioside GM1 are associated with Guillain-Barré Syndrome (GBS) in patients with serologic evidence of a preceding infection with Campylobacter jejuni. Molecular mimicry between C. jejuni Lipopolysaccharide (LPS) and ganglioside GM1 has been proven to be the immunopathogenic mechanism of the disease in the axonal variant of GBS. GM1-positive sera cross-react with several Gal-GalNAc-bearing glycoproteins from the human peripheral nerve and C. jejuni (O:19). This study aimed to examine the immunoreactivity of the digested cross-reactive glycoproteins isolated from the human peripheral nerve and C. jejuni (O:19) with Peanut Agglutinin (PNA) as a marker for the Gal-GalNAc determinant, and with sera from patients with GBS. MATERIALS AND METHODS: For this purpose, the cross-reactive glycoproteins from peripheral nerve and C. jejuni (O:19) were enzymatically digested with trypsin and the obtained peptides were incubated with PNA and GBS sera. RESULTS: Western blot analysis of the separated peptides revealed several bands showing positive reactivity to PNA and to sera from patients with GBS, present in both digests from peripheral nerve and C. jejuni (O:19). CONCLUSIONS: These data indicate the possible molecular mimicry between the cross-reactive glycoproteins present in C. jejuni and human peripheral nerve and its potential role in the development of GBS following infection with C. jejuni (O:19).