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1.
BMC Chem ; 18(1): 118, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38926795

RESUMO

Mathematical manipulation technique has proven to be a very powerful tool for efficient processing and handling of highly overlapped spectra. This work introduced two green and sustainable approaches for the successful recovery of the ternary mixture, Tylosin tartarate (TYL), Sulfadimdine (SLD), and Trimethoprim (TRI). The approaches were constructed using three different methods, derivative ratio spectrum zero-crossing method (DRSZ), double divisor ratio spectra derivative method (DDRD), and factorized derivative ratio method coupled with spectrum subtraction (FDRM-SS). The two approaches succeeded in recovering the three drugs (Linearity range achieved were 0.5-5 µg/mL for TYL, 0.3-1.3 µg/mL for SLD, and 0.3-5 µg/mL for TRI), giving convenient standard deviations and satisfactory recovery percentages. The recommended methods have been verified in accordance with (ICH) guidelines. When the results were statistically compared to the official methods, no significant difference was found. Both AGREE-Analytical GREEnness Metric Approach and Software, and White Analytical Chemistry (WAC) RGB model gave scores of 0.93 and 97.2%, respectively, which proved that the approaches were eco-friendly and abiding by the sustainability principles.

2.
Rep Pract Oncol Radiother ; 28(4): 485-495, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37795234

RESUMO

Background: Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide, and especially in Egypt. Early diagnosis of HCC greatly improves the survival and prognosis of patients. Low sensitivity and specificity of alpha-fetoprotein (AFP) has led to the demand for novel biomarkers of HCC. The aim of the present study was to evaluate the validity of frizzled-7 (FZD7) and glypican-3 (GPC3) gene expression as potential biomarkers for HCC early diagnosis, and to investigate the association between FZD7 rs2280509 polymorphism and HCC risk. Materials and methods: Quantification of FZD7 and GPC3 gene expression by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay, and genotyping FZD 7 (rs2280509 SNP) gene polymorphism using RT-PCR. Results: The current results revealed that FZD7 gene expression had a greater area under the curve (AUC) for identifying HCC than GPC3 gene expression and AFP levels. The combination of the three markers as a panel showed a better diagnostic performance with a greater AUC than any of the single markers alone (p < 0.05). The FZD7 rs2280509 polymorphism (CT) was found to be significantly associated with an increased risk of HCC. The CT genotype and T allele were significantly more prevalent in the HCC group compared to either the cirrhosis (p = 0.03) or control groups (p = 0.0009 and 0.002; respectively). Conclusion: FZD7 and GPC3 gene expressions have a complementary role in early HCC detection, with a greater diagnostic sensitivity and accuracy than AFP. In addition, FZD7 rs2280509 polymorphism is significantly associated with an increased risk of HCC in the Egyptian population.

3.
Anal Biochem ; 659: 114951, 2022 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-36244510

RESUMO

A rapid back flushed (BF) direct sample injection (DSI) high-performance liquid chromatography (HPLC) with UV detection (BF-DSI-HPLC-UV) has been developed to determine terbinafine (TERB) in human serum. For online solid phase extraction step, an isocratic mobile phase of phosphate buffer saline (pH 7.4) at 1 mL/min and a short protein-coated ODS column (PC-ODS-column) were used for the purification and enrichment of TERB. Two different chromatographic modes of PC-ODS-column were simultaneously operated. Macromolecular proteins were extracted by size-exclusion liquid chromatography, while TERB trapping and enrichment were achieved through reversed-phase liquid chromatography. The clear fraction containing TERB was transferred from the PC-ODS-column by BF mode onto the quantification step through a high pressure switching valve. An analytical mobile phase consisting of 80% methanol and 1% triethylamine in distilled deionized water (pH) 6 at 1 mL/min was used for the final separation on an ODS analytical column. TERB was quantified and detected by UV-detector at 224 nm. The proposed method showed high correlation coefficient (>0.999) over the concentrations range 4-1600 ng/mL with recoveries ranging from 98.48 to 93.86%. Measurement of TERB concentration in serum after administration of a single dose of 250 mg oral tablet was used to evaluate the applicability of the BF-DSI-HPLC-UV for pharmacokinetic study.


Assuntos
Monitoramento de Medicamentos , Extração em Fase Sólida , Humanos , Cromatografia Líquida de Alta Pressão/métodos , Terbinafina , Cromatografia em Gel , Indicadores e Reagentes , Reprodutibilidade dos Testes
4.
Cureus ; 14(4): e24125, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35573500

RESUMO

BACKGROUND: In contrast to other breast surgeries, modified radical mastectomy (MRM) with axillary lymph node clearance involves intense tissue dissection, with postoperative seroma formation and pain being the major complaints affecting patients. Among these, 40% of females experience acute postoperative pain, and between 25 to 60% develop persistent chronic postsurgical pain. The rationale of this study was that minimally invasive procedures can result in immediate pain relief in patients undergoing mastectomy, which has been proven to satisfy their needs and lead to early discharge in the local population. OBJECTIVE: This study determined to find out the efficacy of instilling bupivacaine on wounds by means of surgical drains in controlling pain after MRM. METHODOLOGY: This was a randomized control study trial that was carried out in Surgical Unit 1, Ward 3, Jinnah Postgraduate Medical Centre, Karachi, from November 2020 to April 2021. All patients tested negative for coronavirus disease 2019 (COVID-19) by PCR test before randomly allocating them into two groups. Thirty women in Group B received 40 ml of 0.25% injection bupivacaine, and 30 in Group C received no drug. Duration of analgesia was recorded as time in hours when the patient was received after surgery in the post-anesthesia care unit until the patient felt ache and discomfort of > three scores according to the visual analog pain score chart (VAS). RESULTS: The average age was 52.48±4.76 years. The mean period of time during which analgesia was observed was significantly higher in Group B as compared to Group C (10.93±1.84 vs 5.03±1.35 hours, p=0.0005). CONCLUSION: There is improvement in postoperative analgesia after instilling bupivacaine through surgical drains on wound beds in MRM patients.

5.
Artigo em Inglês | MEDLINE | ID: mdl-34808576

RESUMO

A simple, cost-effective and sensitive liquid chromatography-based bio-analytical method has been developed and validated for therapeutic drug monitoring of fluconazole (FLUC) in human serum. Integration of online mixed-mode solid-phase extraction (SPE) into the analytical system was the key for direct injection of untreated serum samples. A short protein-coated (PC) µBondapak CN silica column (PC-µB-CN-column) as a SPE tool and phosphate buffer saline (PBS) (pH 7.4) as an eluent were applied in the extraction step. PC-µB-CN-column operates in two different chromatographic modes. Using PBS, proteins were extracted from serum samples by size-exclusion liquid chromatography, while FLUC trapping was reversed-phase liquid chromatography dependent. FLUC was then eluted from the PC-µB-CN-column onto the quantification position using a mixture of acetonitrile-distilled deionized water (20:80, v/v) as an eluent and ODS analytical column. FLUC was separated at ambient temperature (22 ± 1 °C) and detected at 260 nm. The method was linear over the range of 200-10000 ng/mL. FLUC recovery in untreated serum samples ranged from 97.8 to 98.8% and showed good accuracy and precision. The reliability of the developed method was evaluated by studying the pharmacokinetic profile of FLUC in humans after an oral administration of a single 150 mg tablet.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Monitoramento de Medicamentos/métodos , Fluconazol/sangue , Fluconazol/isolamento & purificação , Extração em Fase Sólida/métodos , Cromatografia de Fase Reversa/métodos , Fluconazol/química , Fluconazol/farmacocinética , Humanos , Limite de Detecção , Modelos Lineares , Masculino , Reprodutibilidade dos Testes
6.
Transfusion ; 60 Suppl 1: S4-S9, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32134129

RESUMO

BACKGROUND: Pediatric patients with sepsis in intensive care units are at high risk of developing anemia, which might have adverse effects on their prognosis. This study aimed to evaluate the impact of red blood cell (RBC) transfusion on the outcomes of patients admitted to a pediatric intensive care unit (PICU) with sepsis. METHODS: We conducted a prospective randomized clinical trial, enrolling 67 children, aged 2 to 144 months who were admitted to a PICU with a new episode of sepsis from November 2017 to April 2018. Patients were allocated randomly to two groups: Group 1, liberal transfusion strategy group, including 33 patients who had initial hemoglobin (Hb) between 7 or greater and less than 10 g/dL and received an RBC top-up transfusion to 12 g/dL; and Group 2, restrictive strategy group, including 34 patients who had the same Hb range and did not receive RBCs. Patients with Hb less than 7 or greater than 10 g/dL were excluded. RESULTS: Of 33 patients who received liberal transfusions, 31 (93.94%) required ventilation, and 29 (87.88%) had multiorgan dysfunction. They had a significantly lengthier hospital stay and a higher incidence of acute respiratory distress syndrome and acute lung injury. Moreover, mortality was significantly higher in the liberal transfusion group (42.4% vs. 17.6%). CONCLUSIONS: Compared to the restrictive transfusion strategy, liberal transfusion might be associated with a worse outcome. However, the possible role of other known and unknown confounding factors and minor protocol violations should be taken into consideration. We recommend minimizing factors worsening anemia in PICU patients to reduce the need for transfusion.


Assuntos
Transfusão de Eritrócitos/efeitos adversos , Sepse/diagnóstico , Criança , Pré-Escolar , Transfusão de Eritrócitos/métodos , Hemoglobinas/análise , Humanos , Unidades de Terapia Intensiva Pediátrica , Tempo de Internação , Insuficiência de Múltiplos Órgãos/etiologia , Consumo de Oxigênio , Estudos Prospectivos , Sepse/etiologia , Resultado do Tratamento
7.
Transfus Clin Biol ; 26(4): 279-283, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30713045

RESUMO

BACKGROUND: Red blood cell (RBC) aging in transfusion medicine is characterized by alteration of many biochemical and morphological integrity of the cell referred to as red cell storage lesion (RCSL), CD47 is a protective marker expressed on RBCs that salvage the cell from phagocytosis. 2,3-diphosphoglycerate (2,3-DPG) tends to have a greater affinity towards deoxygenated hemoglobin. Any oxygen unloading at tissue capillaries are facilitated by 2,3-DPG, and any alterations in its levels can significantly interfere with oxygen release. Alteration of both CD47 expression and 2,3-DPG levels during red cell storage may serve as markers in the development of RCSL. The aim of this study was to validate the impact of storage time and leuco-depletion on CD47 expression on the RBCs, which could be a prospective marker for detection of RBCs viability and to clarify if the changes in CD47 expression and 2,3-DPG levels are correlated during storage of Packed RBCs. SUBJECTS AND METHODS: One hundred samples from Packed RBCs units were divided into two groups [Group 1 comprised unfiltered packed red cell units (n=50), whereas Group 2 included filtered "leuco-reduced" red cell units (n=50)]. Collection of samples was executed on days 0, 1 and 21. Each sample was measured for 2,3-DPG and alteration of CD47 expression on RBC using flow cytometry. RESULTS: Decreased CD47 expression along the storage period was statistically significant in both groups (P<0.05). Interestingly, the expression of CD47 was significantly higher in group 2 than group 1 on day zero, 1st and 21st days (P<0.05). Additionally, a statistically significant decrease in 2,3-DPG level was detected at day 21 of storage in group 1 compared to group 2 with a P-value of <0.001. There was a significant positive correlation (r=0.570, P<0.001) between CD47 MFI on RBC during storage and the level of 2,3-DPG at day 21 from packed RBCs storage. CONCLUSION: Older unfiltered RBC possesses lower expression of CD47 and low levels of 2,3-DPG, however filtration (leucoreduction) of RBCs units may help to retain considerable levels of 2,3-DPG and CD47 and hence sustains preservation of RBCs through reduction of phagocytosis.


Assuntos
2,3-Difosfoglicerato/sangue , Preservação de Sangue , Antígeno CD47/biossíntese , Envelhecimento Eritrocítico , Transfusão de Eritrócitos , Eritrócitos/metabolismo , Procedimentos de Redução de Leucócitos , Adulto , Biomarcadores , Antígeno CD47/sangue , Feminino , Citometria de Fluxo , Humanos , Masculino , Fagocitose , Fatores de Tempo
8.
J Chromatogr Sci ; 57(2): 177-185, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30272145

RESUMO

Rapid and simple micellar electrokinetic chromatography (MEKC) with in-capillary derivatization and fluorescence detection has been developed to determine morphine in human serum. The sample was introduced into a background electrolyte (BGE) containing potassium ferricyanide, whereas morphine was oxidized into highly fluorescent product, pseudomorphine. Different parameters for derivatization and subsequent separation were systematically investigated for the analysis of morphine in serum. Efficient performance of the developed MEKC system was carried out in a single run using BGE made up of 70 mM sodium tetraborate decahydrate (pH 10.5), 0.30 mM potassium ferrricyanide, 80 mM sodium dodecyl sulfate, and applied voltage of 9 kV. The combination of MEKC with in-capillary derivatization of morphine was successfully achieved with a high degree of sensitivity. The validation of the method showed good linearity between areas of morphine and the corresponding concentrations over the range of 5-5000 ng/mL. Excellent accuracy and precision were obtained at all concentration levels. The mean recoveries of morphine were ranging from 83.86 to 94.45%. The validated MEKC method successfully permitted determination of morphine in clinical samples after a single oral dose of controlled release morphine sulfate tablets.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Eletroforese Capilar/métodos , Morfina/sangue , Humanos , Concentração de Íons de Hidrogênio , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Espectrometria de Fluorescência
9.
Biomed Chromatogr ; 32(10): e4322, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29934999

RESUMO

A sensitive HPLC-MS/MS method was established for the quantification of ceftriaxone sodium (CFT) and lidocaine HCl (LDC) in human plasma utilizing cefixime (CFX) and tadalafil (TDA) as internal standards. The analytes were extracted from human plasma by protein precipitation using acetonitrile. Chromatographic separation was performed on Kinetex C18 (50.0 × 4.6 mm, 5 µm particle size) column with methanol-0.01 M ammonium acetate pH 6.4 (70: 30, v/v) as mobile phase. Multiple reaction monitoring involving the transitions 555.10 → 396.20, 235.20 → 86.00, 454.20 → 284.80 and 390.20 → 268.20 was utilized to quantify CFT, LDC, CFX and TDA, respectively, using a triple quadrupole mass spectrometer which was operated in positive ion mode. The method revealed linearity in the concentration range of 3.0-300.0 µg/mL for CFT and 3.0-300.0 ng/mL for LDC. The validation of the method was achieved in accordance to the US Food and Drug Administration guidelines. A pharmacokinetic study was performed on healthy Egyptian volunteers after intramuscular injection of sterile ceftriaxone sodium (1 g CFT dissolved in 3.5 mL of 1% LDC) after approval from the ethics committee. The pharmacokinetic parameters were: Cmax 141.15 ± 39.84 (µg/mL) and 55.02 ± 9.36 (ng/mL); tmax (h) 2.50 ± 0.50 and 1.5 ± 0.50; t½ (h) 7.30 ± 2.98 and 4.23 ± 1.96; and Kel (h-1 ) 0.10 ± 0.04 and 0.20 ± 0.13 for CFT and LDC, respectively.


Assuntos
Ceftriaxona/sangue , Ceftriaxona/farmacocinética , Cromatografia Líquida de Alta Pressão/métodos , Lidocaína/sangue , Lidocaína/farmacocinética , Espectrometria de Massas em Tandem/métodos , Ceftriaxona/administração & dosagem , Ceftriaxona/química , Estabilidade de Medicamentos , Humanos , Injeções Intramusculares , Lidocaína/administração & dosagem , Lidocaína/química , Modelos Lineares , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
10.
J Clin Transl Hepatol ; 5(2): 109-118, 2017 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-28660148

RESUMO

Background and Aims: Nonalcoholic fatty liver disease (NAFLD) is a silent disease; its spectrum includes simple steatosis, nonalcoholic steatohepatitis and fibrosis. Pro- and anti-inflammatory cytokines play roles in the pathogenesis of NAFLD and insulin resistance (IR). Moreover, plasma cell antigen-1 (PC-1) is related to IR and associated with NAFLD progression. Therefore, we aimed to detect biomarkers, ultrasonographic and anthropometric findings capable of differentiating NAFLD grades, since most previous investigators were concerned more with NAFLD patients without classifying them into grades. Methods: A total of 87 NAFLD patients (31 with grade 1 (mild NAFLD), 26 with grade 2 (moderate NAFLD) and 30 with grade 3 (severe NAFLD) were included in the study, in addition to 47 controls (grade 0). All subjects underwent ultrasonographic examination for NAFLD diagnosis. Serum interleukin-10 (IL-10), plasma interleukin-18 (IL-18) and plasma PC-1 levels were determined using enzyme-linked immunosorbent assay. Results: Homoeostasis model assessment (HOMA)-IR was higher in different NAFLD grades than in controls. Ultrasonographic and anthropometric findings and lipid profile indices (except for high-density lipoprotein cholesterol, which was decreased) were increased with NAFLD progression. Grade 3 patients showed significant increase in levels of IL-18 and significant decrease in IL-10 and PC-1 levels when compared to grade 1 patients. Conclusion: Anthropometric and ultrasonographic findings were valuable in differentiating NAFLD grades. IR is very important in NAFLD pathogenesis. IL-18, HOMA-index and PC-1 levels could be used to differentiate between NAFLD grades, together with other measurements.

11.
J Chromatogr Sci ; 53(8): 1353-60, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25834172

RESUMO

A simple, rapid and environment-friendly direct injection HPLC method for the determination of methyldopa (MTD) in human serum has been developed and validated. The method was based on cleanup and separation of MTD from serum by mixed-mode liquid chromatography using a single protein-coated TSK gel ODS-80 TM analytical column (50 × 4.0 mm i.d., 5 µm). The protein-coated column exhibited excellent resolution, selectivity and functioned in two chromatographic modes: size-exclusion chromatography [i.e., solid-phase extraction (SPE) for serum proteins] and reversed-phase chromatography for the final separation of MTD. SPE and HPLC separation were carried out simultaneously with a green mobile phase consisting of acetate buffer (0.1 M, pH 2.4) at a flow rate of 1 mL/min and at room temperature (23 ± 1°C). The eluent was monitored at emission and excitation wavelengths of 320 and 270 nm, respectively. A calibration curve was linear over the range of 0.1-30 µg/mL with a detection limit of 0.027 µg/mL. This online SPE method was successfully applied to real samples obtained from patients receiving MTD therapy.


Assuntos
Cromatografia em Gel/métodos , Cromatografia Líquida de Alta Pressão/métodos , Metildopa/sangue , Adulto , Cromatografia em Gel/instrumentação , Cromatografia Líquida de Alta Pressão/instrumentação , Humanos , Limite de Detecção , Modelos Lineares , Masculino , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos
12.
J Chromatogr Sci ; 52(10): 1308-16, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24248558

RESUMO

Successful simultaneous diastereomeric separation and sensitive determination of two pairs of triterpenoidal saponins have been achieved by capillary electrophoresis (CE) using ß-cyclodextrin (ß-CD) as a stereoselective agent to cooperate with borate complexation. A usual technique for isolation and group separation of saponins was developed as an appropriate purification step prior to the determination of individual saponins by CE. Soyasaponin I ( S1: ), azukisaponin V ( S2: ), bersimoside I ( S3: ) and bersimoside II ( S4: ) could be well separated within 14 min in a fused-silica capillary (60 cm long to the detector with an additional 10 cm to the cathode; 75 µm i.d.). The background electrolyte was borate buffer (80 mM, pH 10), containing 24 mM ß-CD. The separation voltage was 14 kV with a detection wavelength of 195 nm. The sample was electrokinetically injected using a voltage of 16 kV for 12 s. Methanol (70%) was used as the diluent for field-amplified sample stacking after hydrodynamic injection of short water plug (5 cm, 4 s). The method was partially validated for linearity, repeatability, reproducibility, limits of detection and limits of quantification. The correlation coefficients of the calibration curves were all >0.998, and the recoveries were from 98.23 to 96.21%.


Assuntos
Eletroforese Capilar/métodos , Saponinas/análise , Saponinas/química , beta-Ciclodextrinas/química , Boratos/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Modelos Lineares , Extratos Vegetais/química , Reprodutibilidade dos Testes , Sementes/química , Trifolium/química
13.
J Chromatogr Sci ; 51(6): 544-51, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23097580

RESUMO

A simple, sensitive, and selective online pre-column derivatization high-performance liquid chromatographic method was developed and validated for the first time to determine trace levels of folic acid (FA). An oxidant cerium (IV) trihydroxyhydroperoxide packed reactor was used for pre-column oxidation and was combined by column switching with a C18 analytical column for sample enrichment and separation. The method was based on oxidative cleavage of FA into highly fluorescence products, 2-amino-4-hydroxypteridine-6-carboxaldehyde and the corresponding 2-amino-4-hydroxypteridine-6-carboxylic acid, during the flow of 0.04 M phosphate buffer (pH 3.5) containing the analyte through packed reactor at a flow rate of 0.2 mL/min and 40°C. The fluorescent products were enriched on the head of the analytical column for the final separation. The separation was performed at room temperature using a mobile phase consisting of phosphate buffer (0.04 M, pH 3.5) and acetonitrile (90:10, v/v). The eluents were monitored at emission and excitation wavelengths of 463 and 367 nm, respectively. The method showed excellent recovery, precision and accuracy with detection limits of 0.067 ng/mL from 500 µL of sample FA. The developed method was successfully applied to the determination of FA in pharmaceutical formulations and showed a recovery of 99.31% and a relative standard deviation of 1.72%.


Assuntos
Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia Líquida de Alta Pressão/métodos , Ácido Fólico/análise , Cério/química , Ácido Fólico/química , Ácido Fólico/isolamento & purificação , Concentração de Íons de Hidrogênio , Limite de Detecção , Modelos Lineares , Peróxidos/química , Reprodutibilidade dos Testes , Temperatura
14.
J Pharm Anal ; 3(1): 28-35, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29403793

RESUMO

A new simple, sensitive and precise green analytical procedure using an automated packed-reactor derivatization technique coupled with on-line solid-phase enrichment (SPEn) has been developed and evaluated to determine trace levels of methotrexate (MTX). The method was based on injection of MTX into a flowing stream of phosphate buffer (0.04 M, pH 3.4), carried through the packed oxidant reactor of Cerium (IV) trihydroxyhydroperoxide for oxidative cleavage of the drug into highly fluorescent product, 2,4-diaminopteridine-6-carboxylic acid, followed by SPEn on a head of short ODS column (10 mm×4.6 mm i.d., 5 µm particle size). The flow rate was 0.25 mL/min and packed reactor temperature was 40 °C. The trapped product was back-flush eluted from the ODS column to the detector by column-switching with an environmentally friendly mobile phase consisting of ethanol and phosphate buffer (0.04 M, pH 3.4) in the ratio of 5:95 (v/v). The eluent was monitored at emission and excitation wavelengths of 460 and 360 nm, respectively. The calibration curve was linear over the concentration range of 1.25-50 ng/mL with a detection limit of 0.08 ng/mL. The method was successfully applied to determine MTX in pharmaceutical formulations with mean percentage recovery ranging from 99.48 to 99.60.

15.
Chem Cent J ; 6(1): 155, 2012 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-23234331

RESUMO

BACKGROUND: Analysis of folic acid (FA) is not an easy task because of its presence in lower concentrations, its lower stability under acidic conditions, and its sensitiveness against light and high temperature. The present study is concerned with the development and validation of an automated environmentally friendly pre-column derivatization combined by solid-phase enrichment (SPEn) to determine low levels of FA. RESULTS: Cerium (IV) trihydroxyhydroperoxide (CTH) as a packed oxidant reactor has been used for oxidative cleavage of FA into highly fluorescent product, 2-amino-4-hydroxypteridine-6-carboxylic acid. FA was injected into a carrier stream of 0.04 M phosphate buffer, pH 3.4 at a flow-rate of 0.25 mL/min. The sample zone containing the analyte was passed through the CTH reactor thermostated at 40°C, and the fluorescent product was trapped and enriched on a head of small ODS column (10 mm x 4.6 mm i.d., 5 µm particle size). The enriched product was then back-flush eluted by column-switching from the small ODS column to the detector with a greener mobile phase consisting of ethanol and phosphate buffer (0.04M, pH 3.4) in the ratio of 5:95 (v/v). The eluent was monitored fluorimetrically at emission and excitation wavelengths of 463 and 367 nm, respectively. The calibration graph was linear over concentrations of FA in the range of 1.25-50 ng/mL, with a detection limit of 0.49 ng/mL. CONCLUSION: A new simple and sensitive green analytical procedure including on-line pre-column derivatization combined by SPEn has been developed for the routine quality control and dosage form assay of FA at very low concentration level. The method was a powerful analytical technique that had excellent sensitivity, sufficient accuracy and required relatively simple and inexpensive instrumentation.

16.
J Chromatogr Sci ; 50(2): 91-6, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22298756

RESUMO

A sensitive and efficient on-line clean up and pre-concentration method has been developed using column-switching technique and protein-coated µ-Bondapak CN silica pre-column for quantification of ambroxol (AM) in human serum. The method is performed by direct injection of serum sample onto a protein-coated µ-Bondapak CN silica pre-column, where AM is pre-concentrated and retained, while proteins and very polar constituents are washed to waste using a phosphate buffer saline (pH 7.4). The retained analyte on the pre-column is directed onto a C(18) analytical column for separation, with a mobile phase consisting of a mixture of methanol and distilled deionized water (containing 1% triethylamine adjusted to pH 3.5 with ortho-phosphoric acid) in the ratio of 50:50 (v/v). Detection is performed at 254 nm. The calibration curve is linear over the concentration range of 12-120 ng/mL (r(2) = 0.9995). The recovery, selectivity, linearity, precision, and accuracy of the method are convenient for pharmacokinetic studies or routine assays.


Assuntos
Ambroxol/sangue , Expectorantes/análise , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Limite de Detecção , Padrões de Referência
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