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Vettorazzi A, González-Peñas E, de Cerain AL. Ochratoxin A kinetics: A review of analytical methods and studies in rat model. Food Chem Toxicol 2014; 72:273-88. [DOI: 10.1016/j.fct.2014.07.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 07/04/2014] [Accepted: 07/13/2014] [Indexed: 10/25/2022]
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Corcuera L, Vettorazzi A, Arbillaga L, González-Peñas E, López de Cerain A. An approach to the toxicity and toxicokinetics of aflatoxin B1 and ochratoxin A after simultaneous oral administration to fasted F344 rats. Food Chem Toxicol 2012; 50:3440-6. [DOI: 10.1016/j.fct.2012.06.048] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/25/2012] [Accepted: 06/26/2012] [Indexed: 11/29/2022]
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Amézqueta S, Schorr-Galindo S, Murillo-Arbizu M, González-Peñas E, López de Cerain A, Guiraud J. OTA-producing fungi in foodstuffs: A review. Food Control 2012. [DOI: 10.1016/j.foodcont.2012.01.042] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Murillo-Arbizu M, González-Peñas E, Amézqueta S. Comparison between capillary electrophoresis and high performance liquid chromatography for the study of the occurrence of patulin in apple juice intended for infants. Food Chem Toxicol 2010; 48:2429-34. [PMID: 20566341 DOI: 10.1016/j.fct.2010.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 05/31/2010] [Accepted: 06/01/2010] [Indexed: 11/29/2022]
Abstract
Apple juice samples intended for infants purchased in Navarra (Spain) have been analyzed for PAT occurrence. Two capillary electrophoresis methods, based on a MEKC and a CEC system, and an HPLC method were evaluated for the aforementioned study. The CEC system gave less satisfying separations and several practical problems, so samples have been analyzed by MEKC and HPLC. Both methods have been comparable in terms of recovery, precision, limits of detection, volume of organic solvents used and adequate selectivity with regard to PAT and HMF. The analysis time in HPLC has been slightly lower than in the MEKC methodology. The PAT levels obtained in apple juice by both validated methods showed a strong correlation (p<0.001). Therefore, both methodologies are useful for the accurate quantification of patulin in this matrix. The PAT levels obtained in the 20 infant apple juices samples were in a range between <LOD and 29.6 microg L(-1), with a mean concentration of 8.0 microg L(-1) which implies a dietary intake estimation of 104 ng kg(-1)b.w.day(-1) considering a body weight of 10 kg and an apple juice consumption of 130 mL day(-1), 26% of the PMTDI recommended by JECFA.
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Affiliation(s)
- M Murillo-Arbizu
- Organic and Pharmaceutical Chemistry Department, School of Pharmacy, University of Navarra, 31080 Pamplona, Navarra, Spain
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Amézqueta S, González-Peñas E, Dachoupakan C, Murillo-Arbizu M, de Cerain AL, Guiraud JP. OTA-producing fungi isolated from stored cocoa beans. Lett Appl Microbiol 2009; 47:197-201. [PMID: 19552785 DOI: 10.1111/j.1472-765x.2008.02409.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS The aim of this study was to identify fungal populations in unroasted cocoa beans stored in Spain in order to evaluate the ochratoxin A (OTA)-production ability of certain Aspergillus isolates. METHODS AND RESULTS Twenty batches of cocoa beans from different origins and with different OTA content were selected for this study. Three Aspergillus carbonarius and 13 Aspergillus niger aggregate strains isolated from these cocoa bean samples were selected to evaluate their OTA synthesis ability, being the only A. carbonarius isolates which are OTA producers [<limit of detection (LOD) = 3520 microg kg(-1) culture medium; LOD = 6 microg kg(-1) culture medium]. CONCLUSIONS No correspondence was found between the OTA levels in cocoa beans and the presence of OTA-producing fungi. Nonetheless, some samples contained A. carbonarius with a high OTA-producing ability and, consequently, specific fungal controls should be set up during storage to avoid this toxin. SIGNIFICANCE AND IMPACT OF THE STUDY Toxigenic fungi in cocoa beans are not well understood. This study attempted to identify these fungi and evaluate their OTA-producing ability.
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Affiliation(s)
- S Amézqueta
- Organic and Pharmaceutical Chemistry Department, Faculty of Pharmacy, University of Navarra, Pamplona, Spain
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Amézqueta S, González-Peñas E, Lizarraga T, Murillo-Arbizu M, López de Cerain A. A simple chemical method reduces ochratoxin A in contaminated cocoa shells. J Food Prot 2008; 71:1422-6. [PMID: 18680942 DOI: 10.4315/0362-028x-71.7.1422] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus and Penicillium species, which contaminates cocoa among other food commodities. It has been previously demonstrated that the toxin is concentrated in cocoa shells. The aim of this study was to assay a simple chemical method for ochratoxin A reduction from naturally contaminated cocoa shells. In order to determine the efficiency of the method, a high-performance liquid chromatography method with fluorescence detection was set up beforehand and validated. Ochratoxin A was extracted from cocoa shells with methanol-3% sodium bicarbonate solution and then purified with immunoaffinity columns. The recovery attained was 88.7% (relative standard deviation = 6.36%) and the limits of detection and quantification were 0.06 and 0.2 kg/kg, respectively. For decontamination experiments, the solvent extractor ASE 200 was used. First, aqueous solutions of 2% sodium bicarbonate and potassium carbonate were compared under the same conditions (1,500 lb/in2 at 40 degrees C for 10 min). Higher ochratoxin A reduction was obtained with potassium carbonate (83 versus 27%). Then, this salt was used under different conditions of pressure, temperature, and time. The greatest ochratoxin A reduction was achieved with an aqueous potassium carbonate solution (2%), at 1,000 lb/in2 at 90 degrees C for 10 min. This method could probably be applicable to the cocoa industry because it is fast and relatively economic. From the point of view of human health, the use of potassium carbonate, partially eliminated by rinsing the sample with water, does not likely represent a risk for human health.
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Affiliation(s)
- S Amézqueta
- Organic and Pharmaceutical Chemistry Department, Faculty of Pharmacy, University of Navarra, 31008 Pamplona, Spain
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Murillo M, González-Peñas E, Amézqueta S. Determination of patulin in commercial apple juice by micellar electrokinetic chromatography. Food Chem Toxicol 2008; 46:57-64. [PMID: 17707570 DOI: 10.1016/j.fct.2007.06.024] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 02/21/2007] [Accepted: 06/22/2007] [Indexed: 11/20/2022]
Abstract
A novel and validated micellar electrokinetic capillary chromatography (MEKC) method using ultraviolet detection (UV) has been applied to the quantitative analysis of patulin (PAT) in commercial apple juice. Patulin was extracted from samples with an ethylacetate solution. The micellar electrokinetic capillary chromatography (MECK) parameters studied for method optimization were buffer composition, voltage, temperature, and a separation between PAT and 5-hydroxymethylfurfural (HMF) (main interference in apple juice PAT analysis) peaks until reaching baseline. The method passes a series of validation tests including selectivity, linearity, limit of detection and quantification (0.7 and 2.5 microgL(-1), respectively), precision (within and between-day variability) and recovery (80.2% RSD=4%), accuracy, and robustness. This method was successfully applied to the measurement of 20 apple juice samples obtained from different supermarkets. One hundred percent of the samples were contaminated with a level greater than the limit of detection, with mean and median values of 41.3 and 35.7 microgL(-1), respectively.
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Affiliation(s)
- M Murillo
- Organic and Pharmaceutical Chemistry Department, University of Navarra, C/Irunlarrea 1, C.P. 31008 Pamplona, Navarra, Spain
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González-Peñas E, Leache C, López de Cerain A, Lizarraga E. Comparison between capillary electrophoresis and HPLC-FL for ochratoxin A quantification in wine. Food Chem 2006. [DOI: 10.1016/j.foodchem.2005.05.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
Ochratoxin A (OTA) is a nephrotoxic mycotoxin produced by species of the genus Penicillium and Aspergillus that is present in food and feed as a natural contaminant. It modifies the immune function in animals and inhibits the proliferative response of lymphocytes in vitro. The toxic effect of OTA (0.5, 2, 20 microM) in lympho-proliferative response, natural killer (NK) cell activity, cytotoxic T lymphocytes (CTL) activity and macrophages' bacteriolytic capability was studied in vitro after 1 hour of treatment. The proliferative response of lymphocytes to concanavalin A and lipopolysaccharide was not affected by OTA; the cytotoxic activity of NK cells was dose-dependent decreased; the CTL activity was significantly decreased at the lowest concentration; the bacteriolytic activity of macrophages varied only slightly. These in vitro results reproduced, at least in part, some effects detected previously in vivo. The protein synthesis inhibition and the oxidative metabolism of OTA coupled to the prostaglandin synthesis are probably implicated in NK cells' toxicity, because the effects were reverted by the addition of phenylalanine or piroxicam to the culture medium. The induction of apoptosis seems to be the principal mechanism of action in the CTL effect. The intracellular concentration of OTA after 1 hour was analysed by HPLC and was found to be proportional to the quantity of OTA added to the culture medium for the three cell types; the presence of phenylalanine and piroxicam on the culture medium did not change the intracellular OTA concentration.
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Affiliation(s)
- L Alvarez-Erviti
- Food Sciences and Toxicology Department, Faculty of Pharmacy, University of Navarra, Irunlarrea, Pamplona, Spain
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Pérez De Obanos A, González-Peñas E, López De Cerain A. Influence of roasting and brew preparation on the ochratoxin A content in coffee infusion. ACTA ACUST UNITED AC 2005; 22:463-71. [PMID: 16019819 DOI: 10.1080/02652030500090042] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A study of the effect of coffee processing in the ochratoxin A (OTA) level has been carried out from the green beans to the drinking form. The analysis of OTA has been carried out by an in-house validated HPLC method with fluorescence detection. The limits of detection were 0.04 microg/kg for green and roasted coffee, and 0.01 microg/L for coffee brew. Thirty-six green coffee samples of different origin (Colombia, Costa Rica, Brazil, Vietnam, India and Uganda) were analysed. The highest concentrations of OTA were found in Vietnamese samples -- Robusta species treated by dry processing -- (range 0.64-8.05 microg/kg), that also showed the highest percentage of defective beans (7.6%). These contaminated samples were roasted in a process that controlled loss of weight and color, as in the industry. A mean reduction of 66.5% was obtained, but the reduction seems to be heterogeneous. Coffee brew was prepared by the three brewing processes more utilized in Europe: moka, auto-drip and espresso. A reduction of the OTA level has been attained, being greater when using a espresso coffee maker (49.8%) than when using auto-drip (14.5%) or moka brewing (32.1%). Therefore, the method of coffee brew preparation plays a key role in the final OTA human exposure.
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Affiliation(s)
- A Pérez De Obanos
- Food Science and Toxicology Department, University of Navarra, Pamplona, Spain
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Abstract
The aim of this study was to investigate the influence of the shelling process on the presence of ochratoxin A (OTA) in cocoa samples. Twenty-two cocoa samples were analysed for the determination of OTA before (cocoa bean) and after undergoing manual shelling process (cocoa nib). In order to determine OTA contamination in cocoa samples, a validated high-performance liquid chromatography (HPLC) method with fluorescence detection was used for the quantitative analysis of ochratoxin A (OTA). In both types of samples, OTA was extracted with methanol-3% sodium hydrogen carbonate solution and then purified using immunoaffinity columns prior to HPLC analysis. Due to the fact that different recovery values were obtained for OTA from both types of samples, a revalidation of the method in the case of cocoa nibs was needed. Revalidation was based on the following criteria: Selectivity, limits of detection and quantification (0.03 and 0.1 microg kg(-1), respectively), precision (within-day and between-day variability) and recovery 84.2% (RSD = 7.1%), and uncertainty (30%). Fourteen of the twenty-two cocoa bean samples (64%) suffered a loss of OTA of more than 95% due to shelling, six samples suffered a loss of OTA in the range 65-95%, and only one sample presented a reduction of less than 50%. The principal conclusion derived from this study is that OTA contamination in cocoa beans is concentrated in the shell; therefore, improvements of the industrial shelling process could prevent OTA occurrence in cocoa final products.
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Affiliation(s)
- S Amézqueta
- Organic and Pharmaceutical Chemistry Department, Ed. CIFA Faculty of Pharmacy, University of Navarra, Phamplona, Spain
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Amézqueta S, González-Peñas E, Murillo M, López de Cerain A. Validation of a high-performance liquid chromatography analytical method for ochratoxin A quantification in cocoa beans. ACTA ACUST UNITED AC 2004; 21:1096-106. [PMID: 15764339 DOI: 10.1080/02652030400019422] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A validated high-performance liquid chromatography (HPLC) method with fluorescence detection for the quantitative analysis of ochratoxin A (OTA) in cocoa beans is described. OTA was extracted with methanol-3% sodium hydrogen carbonate solution and then purified with immunoaffinity columns before its analysis by HPLC. The validation of the analytical method was based on the following criteria: selectivity, linearity, limit of detection and quantification, precision (within- and between-day variability) and recovery, robustness and uncertainty. Detection and quantification limits were 0.04 and 0.1 mug kg(-1), respectively. Recovery was 88.9% (relative standard deviation = 4.0%). This method was successfully applied to the measurement of 46 cocoa bean samples of different origins. A total of 63% of cocoa bean samples was contaminated with a level greater than the limit of detection. The means and medians obtained for cocoa bean were 1.71 and 1.12 mug kg(-1), respectively. Surveillance controls should be set up in both crops and factories involved in transformation processes to avoid this mycotoxin in final products.
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Affiliation(s)
- S Amézqueta
- Organic and Pharmaceutical Chemistry Department, University of Navarra, E-31008 Pamplona, Spain
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González-Peñas E, Leache C, Viscarret M, Pérez de Obanos A, Araguás C, López de Cerain A. Determination of ochratoxin A in wine using liquid-phase microextraction combined with liquid chromatography with fluorescence detection. J Chromatogr A 2004; 1025:163-8. [PMID: 14763800 DOI: 10.1016/j.chroma.2003.10.113] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
A liquid-liquid microextraction technique (LPME) has been applied to the extraction of ochratoxin A (OTA) from wine prior to its quantification by HPLC-fluorescence detection. OTA was extracted from wine, through 1-octanol immobilized in the pores of a porous hollow fiber, and introduced into 1-octanol inside the fiber. Recovery was 77%. The method was adequate for quantification of OTA in wine at levels within the range 0.25-10 ng/ml with a LOD of 0.2 ng/ml, and can be a simple and inexpensive alternative to the use of inmunoaffinity columns in order to quantify OTA levels in wine.
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Affiliation(s)
- E González-Peñas
- Organic and Pharmaceutical Chemistry Department, Faculty of Pharmacy, University of Navarra, C/Irunlarrea s/n, 31008 Pamplona, Spain.
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Abstract
With the aim of assessing ochratoxin A (OTA) contamination in wines from a Spanish northern region and the influence of harvest conditions, the following samples were analysed: 40 wines (28 red and 12 white) obtained from grapes cultivated in three different places of the northern Spanish region of Navarra, but in different years, 20 samples in 1997 and 20 in 1998. Wine samples were provided by a viticultural experimental station with very consistent and controlled cultural and enological practices. A high-performance liquid chromatography (HPLC) method with fluorescence detection and immunoaffinity columns was employed (LOD = 0.05 ng ml(-1); method recovery = 101%). Eighty five per cent of the samples from 1997 showed OTA levels >0.05 ng ml(-1) (range 0.056-0.316 ng ml(-1)) and 15% of the samples from 1998 showed OTA levels above the LOD (range 0.074-0.193 ng ml(-1)). Averages detected in 1997 positive samples were 0.185 ng OTA ml(-1) wine (SD = 0.023) in white wine samples (n = 6) and 0.160 ng ml(-1) (SD = 0.119) in the red wine samples (n = 11). These differences between contamination by OTA in the samples from the two different years were attributed to the different quality of the grapes, due to the bad climate in 1997. The possibility of the loss of the mycotoxin was excluded by the analysis of OTA in contaminated wine during 12 months. This study showed that OTA is stable in wine for at least 1 year.
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Affiliation(s)
- A Lopez de Cerain
- Food Science and Technology Department, Faculty of Pharmacy, University of Navarra, E-31008 Pamplona, Spain.
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González-Peñas E, Agarraberes S, López-Ocariz A, García-Quetglas E, Campanero MA, Carballal JJ, Honorato J. A sensitive method for the determination of gemfibrozil in human plasma samples by RP-LC. J Pharm Biomed Anal 2001; 26:7-14. [PMID: 11451637 DOI: 10.1016/s0731-7085(01)00369-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A sensitive high-performance liquid chromatographic assay for the quantitative determination of gemfibrozil is described in this work. Ibuprofen was used as internal standard. The assay involved a single cyclohexane extraction and LC analysis with fluorescence detection. Chromatography was performed at 40 degrees C on a Hypersil ODS column. The mobile phase was a mixture of a solution of phosphoric acid 0.4% and acetonitrile (45:55). The method was validated. The detection limit of this method was 0.025 microg ml(-1); only 0.5 ml of the plasma sample was required for the determination. The calibration graph was linear from 0.05 to 0.5 microg ml(-1) and required a cubic equation from 0.5 to 30 microg ml(-1). Intra and inter-day precision (C.V.) did no exceed 15%. Mean recoveries were of 90.15+/-6.9% (C.V.'s<8%) for gemfibrozil and 93.10% for ibuprofen Applicability of the method was demonstrated by a pharmacokinetic study in normal volunteers who received gemfibrozil by oral route.
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Affiliation(s)
- E González-Peñas
- Departamento de Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad de Navarra, 31008 Pamplona, Spain.
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González-Peñas E, Aldana I, Esteras A, Bruseghini L, Gazzaniga A, Gianesello W. Absorption of sodium diclofenac after ocular administration in rabbit. Arzneimittelforschung 1998; 48:931-4. [PMID: 9793621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Sodium diclofenac (DCF, CAS 1507-79-6) is a non-steroidal anti-inflammatory drug whose activity is mainly due to an inhibitory effect on the synthesis of the prostaglandins. At present, a tendency towards its topical use in the treatment of the inflammatory state of the anterior segment of the eye as an alternative to the steroid drugs is observed. The pharmacokinetics of DCF was studied in rabbits by assessing the ocular and systemic absorption of DCF after administering DCF eye drops. The chromatographic methods available were not sensitive enough to quantify the extremely low drug concentrations which appeared in the biological fluids after ocular treatment. For this reason, the concentrations of DCF in plasma and aqueous humor were evaluated by a coupled liquid chromatography/gas chromatography (LC/GC) method. DCF was absorbed well through the cornea with the aqueous humor concentration peak being 757.8 ng/ml at 120 min. This good ocular absorption of DCF was confirmed by the concentrations observed in plasma. The presence of tramazoline (TMZ, CAS 74195-73-6) in the eye drops increases the levels of DCF in aqueous humor.
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Affiliation(s)
- E González-Peñas
- Center of Investigation in Applied Pharmacobiology (C.I.F.A.), University of Navarra, Spain
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González-Peñas E, Martinez P, Gimeno M, Coronel P. Bioavailability of the iron formulated as natural ferric protein (TM/FMOA) and natural ferric protein + folic acid (TM/FMOA+FOL). Eur J Drug Metab Pharmacokinet 1998; 23:213-7. [PMID: 9725484 DOI: 10.1007/bf03189342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Numerous oral iron preparations are available for the treatment of iron deficiency anemia but only very few studies have been designed to measure the bioavailability of iron preparations. The aim of this assay is to determine the bioavailability of iron formulated as natural ferric protein (TM/FMOA)(FMOA=Ferrimannitol ovalbumin) and natural ferric protein with folic acid (TM/FMOA+FOL) in healthy and anemic rats. Determination of the bioavailability of iron has been carried out by studying the serum level-time curves after i.v. administration of a single dose of 1 mg iron/kg in the form of ferrous sulfate, and after oral administration of 2 mg of iron/kg in the form of TM/FMOA or TM/FMOA+FOL. The Cmax values obtained after oral administration of TM/FMOA and TM/FMOA+FOL are greater in the case of anemic rats, while the tmax values are similar in both types of animals. The bioavailability (F) is greater for the anemic rats (80% approx), and the presence of folic acid does not appear to influence the bioavailability of the iron. This bioavailability data with TM/FMOA can predict good results in further experiments in human beings with iron deficiencies.
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Affiliation(s)
- E González-Peñas
- Organic Chemistry, Research Center in Applied Pharmacobiology (CIFA), University of Navarra, Spain
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Zamalloa E, Dios-Viéitez C, González-Peñas E, Monge A, Aldana I. Determination of a new hypoxia selective agent from 2-quinoxalinecarbonitrile 1,4-di-N-oxides in plasma by high performance liquid chromatography. Arzneimittelforschung 1997; 47:1044-6. [PMID: 9342420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A high performance liquid chromatography (HPLC) method was developed and validated for the determination of 7-chloro-3-[[(N,N-dimethylamino)propyl]amino]-2-quinaxolinecarbonitri le 1,4-di-N-oxide (Q-85), a new hypoxia-selective agent, in plasma. The assay involves extraction into diethylether-dichloromethane (2:1) from plasma and subsequent analysis by reversed-phase HPLC with ultraviolet detection at 292 nm. Response was linear in the range of 0.4-20 micrograms/ml of plasma and the detection limit was 0.05 micrograms/ml. The extraction recovery was about 90%. The within and between day coefficients of variation did not exceed 6.1%. This HPLC assay has been applied to determine Q-85 in plasma samples taken during pharmacokinetic studies in mice.
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Affiliation(s)
- E Zamalloa
- Department of Medicinal Chemistry, University of Navarra, Pamplona, Spain
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Aldana I, González-Peñas E, Fos D, Bruseghini L, Esteras A, Ceppi Monti N, Gianesello V. Pharmacokinetics of thymoxamine in rabbits after ophthalmic and intravenous administration. Eur J Drug Metab Pharmacokinet 1994; 19:79-83. [PMID: 8001598 DOI: 10.1007/bf03188827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The pharmacokinetics of thymoxamine hydrochloride were studied in rabbits by the assessment of its ocular and systemic absorption after instillation of thymoxamine hydrochloride 0.5% eye drops. Plasma levels were compared with those observed after i.v. bolus administration of thymoxamine hydrochloride at 2.5 mg/kg. Deacetylthymoxamine is the main metabolite of thymoxamine, generated by esterase hydrolysis. It was evaluated, as an indication of the parent drug, in aqueous humor and plasma by an HPLC method with fluorescence detection (detection limit = 5 ng/ml). Thymoxamine was found to permeate the cornea and to be hydrolysed very quickly, showing very good absorption with a maximum aqueous humor concentration of deacetylthymoxamine of 2329 ng/ml 15 min after eye drop instillation. The study of the systemic absorption of thymoxamine allowed the exclusion of the possibility of systemic side effects following ocular treatment. In fact, considering the detection limit of the method, the plasma levels of deacetylthymoxamine are certainly more than 100-times lower than those observed with intravenous treatment.
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Affiliation(s)
- I Aldana
- Center of Investigation in Applied Pharmacobiology (CIFA), University of Navarra, Pamplona, Spain
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