Histamine production by Raoultella ornithinolytica in mahi-mahi meat at various storage temperatures

Mahi-mahi meat was inoculated with Raoultella ornithinolytica at 5.0 log CFU/g and stored at −20°C, 4°C, 15°C, 25°C, or 37°C to investigate bacterial growth and formation of total volatile base nitrogen and histamine in mahi-mahi meat. R. ornithinolytica grew rapidly in samples stored at temperature above 15°C. The histamine contents quickly increased to higher than 50 mg/100 g in samples stored at 25°C and 37°C within 12 hours as well as those stored at 15°C within 48 hours. The total volatile base nitrogen contents increased to higher than the index level (30 mg/100 g) for fish decomposition at 25°C within 48 hours and 37°C within 24 hours. However, bacterial growth and histamine formation were controlled by cold storage of the samples at 4°C or below. Once the frozen mahi-mahi samples stored at −20°C for 2 months were thawed and stored at 25°C after 24 hours, histamine started to accumulate rapidly (>50 mg/100 g of fish).     

Reduction of histamine and biogenic amines during salted fish fermentation by Bacillus polymyxa as a starter culture

Bacillus polymyxa D05-1, isolated from salted fish product and possessing amine degrading activity, was used as a starter culture in salted fish fermentation in this study. Fermentation was held at 35°C for 120 days. The water activity in control samples (without starter culture) and inoculated samples (inoculated with B. polymyxa D05-1) remained constant throughout fermentation, whereas the pH value rose slightly during fermentation. Salt contents in both samples were constant in the range of 17.5–17.8% during the first 60 days of fermentation and thereafter increased slowly. The inoculated samples had considerably lower levels of total volatile basic nitrogen (p < 0.05) than control samples at each sampling time during 120 days of fermentation. Aerobic bacterial counts in inoculated samples were retarded during the first 60 days of fermentation and thereafter increased slowly, whereas those of control samples increased rapidly with increased fermentation time. However, the aerobic bacterial counts of control samples were significantly higher (p < 0.05) than those of inoculated samples after 40 days of fermentation. In general, overall biogenic amine contents (including histamine, putrescine, cadaverine, and tyramine) in the control samples were markedly higher (p < 0.05) than those of the inoculated samples throughout fermentation. After 120 days of fermentation, the histamine and overall biogenic amine contents in the inoculated samples were reduced by 34.0% and 30.0%, respectively, compared to control samples. These results emphasize that the application of starter culture with amines degrading activity in salted fish products was effective in reducing biogenic amine accumulation.     

Combination of Extrusion and Fermentation with Lactobacillus plantarum and L. uvarum Strains for Improving the Safety Characteristics of Wheat Bran

Processed wheat bran (W) is of great importance for food and feed. Consequently, the biosafety of W should be evaluated and improved with valorisation strategies. This study tested a design combining extrusion (at temperature of 115 and 130 °C; screw speeds of 16, 20, and 25 rpm) and fermentation with Lactobacillus plantarum and L. uvarum strains for the valorisation of W to provide safer food and feed stock. The influence of different treatments on biogenic amine formation, mycotoxin content, and free amino acids, as well as acidity, microbiological parameters, and sugar concentration, were analysed. This research showed that a combination of extrusion and fermentation with selected strains can change several aspects of W characteristics. There was a significant effect of applied treatments on acidity and the microbiological parameters of W, as well as biogenic amines content. The lowest total mycotoxin concentration (29.8 µg/kg) was found in extruded (130 °C; 25 rpm) and fermented with L. uvarum sample. Finally, the combination of the abovementioned treatments can be confirmed as a prospective innovative pre-treatment for W, capable of potentially enhancing their safety characteristics and composition.     

The effect of vacuum packaging on histamine changes of milkfish sticks at various storage temperatures

The effects of polyethylene packaging (PEP) (in air) and vacuum packaging (VP) on the histamine related quality of milkfish sticks stored at different temperatures (−20°C, 4°C, 15°C, and 25°C) were studied. The results showed that the aerobic plate count (APC), pH, total volatile basic nitrogen (TVBN), and histamine contents increased as storage time increased when the PEP and VP samples were stored at 25°C. At below 15°C, the APC, TVBN, pH, and histamine levels in PEP and VP samples were retarded, but the VP samples had considerably lower levels of APC, TVBN, and histamine than PEP samples. Once the frozen fish samples stored at −20°C for 2 months were thawed and stored at 25°C, VP retarded the increase of histamine in milkfish sticks as compared to PEP. In summary, this result suggested the milkfish sticks packed with VP and stored below 4°C could prevent deterioration of product quality and extend shelf-life.     

Stability of Diluted Adenosine Solutions in Polyolefin Infusion Bags

Background:

Intravenous or intracoronary adenosine is used in the cardiac catherization lab to achieve maximal coronary blood flow and determine fractional flow reserve.

Objective:

To determine the stability of adenosine 10 and 50 µg/mL in either 0.9% sodium chloride injection or 5% dextrose injection in polyolefin infusion bags stored at 2 temperatures, refrigeration (2°C-8°C) or controlled room temperature (20°C-25°C).

Methods:

Adenosine 10 µg/mL and 50 µg/mL solutions were prepared in 50 mL polyolefin infusion bags containing 0.9% sodium chloride injection or 5% dextrose injection and stored at controlled room temperature or under refrigeration. Each combination of concentration, diluent, and storage was prepared in triplicate. Samples were assayed using stability-indicating, reversed-phase high-performance liquid chromatography immediately at time 0 and at 24 hours, 48 hours, 7 days, and 14 days. Stability was defined as retaining 90% to 110% of the initial adenosine concentration. The samples were also visually inspected against a light background for clarity, color, and the presence of particulate matter.

Results:

After 14 days, all samples retained 99% to 101% of the initial adenosine concentration. No considerable change in pH or visual appearance was noted. The stability data indicated no significant loss of drug due to chemical degradation or physical interactions during storage.

Conclusion:

Adenosine solutions of 10 and 50 µg/mL were stable for at least 14 days in 50 mL polyolefin infusion bags of 0.9% sodium chloride injection or 5% dextrose injection stored at controlled room temperature and refrigerated conditions.     

The histamine content of dried flying fish products in Taiwan and the isolation of halotolerant histamine-forming bacteria

Thirty dried flying fish products were purchased from fishing village stores in Taiwan and tested to detect the presence of histamine and histamine-forming bacteria. Except for histamine and cadaverine, the average content of various biogenic amines in the tested samples was less than 3.5 mg/100 g. Eight (26.6%) dried flying fish samples had histamine levels greater than the United States Food and Drug Administration guideline of 5 mg/100 g for scombroid fish and/or scombroid products, whereas four (13.3%) samples contained more than the hazard action level of 50 mg/100 g. One histamine-producing bacterial isolate was identified as Staphylococcus xylosus by 16S rDNA sequencing with polymerase chain reaction amplification. This isolate was capable of producing 507.8 ppm of histamine in trypticase soy broth supplemented with 1.0% l-histidine (TSBH). The S. xylosus isolate was a halotolerant bacterium that had a consistent ability to produce more than 300 ppm of histamine at 3% sodium chloride concentration in TSBH medium after 72 hours.     

Tetrodotoxins in French Bivalve Mollusks—Analytical Methodology,Environmental Dynamics and Screening of Bacterial Strain Collections

Tetrodotoxins (TTXs) are potentially lethal paralytic toxins that have been identified in European shellfish over recent years. Risk assessment has suggested comparatively low levels (44 µg TTX-equivalent/kg) but stresses the lack of data on occurrence. Both bacteria and dinoflagellates were suggested as possible biogenic sources, either from an endogenous or exogenous origin. We thus investigated TTXs in (i) 98 shellfish samples and (ii) 122 bacterial strains, isolated from French environments. We optimized a method based on mass spectrometry, using a single extraction step followed by ultrafiltration without Solid Phase Extraction and matrix-matched calibration for both shellfish and bacterial matrix. Limits of detection and quantification were 6.3 and 12.5 µg/kg for shellfish and 5.0 and 10 µg/kg for bacterial matrix, respectively. Even though bacterial matrix resulted in signal enhancement, no TTX analog was detected in any strain. Bivalves (either Crassostrea gigas or Ruditapes philippinarum) were surveyed in six French production areas over 2.5–3 month periods (2018–2019). Concentrations of TTX ranged from ‘not detected’ to a maximum of 32 µg/kg (Bay of Brest, 17 June 2019), with events lasting 2 weeks at maximum. While these results are in line with previous studies, they provide new data of TTX occurrence and confirm that the link between bacteria, bivalves and TTX is complex.     

Stability of Azacitidine in Sterile Water for Injection

Background:

The product monograph for azacitidine states that once reconstituted, the drug may be held for only 30 min at room temperature or 8 h at 4°C. Standard doses result in wastage of a portion of each vial, and the cost of this wastage is significant, adding about $156 000 to annual drug expenditures at the authors’ institution.

Objective:

To evaluate the stability of azacitidine after reconstitution.

Methods:

Vials of azacitidine were reconstituted with sterile water for injection. At the time of reconstitution, the temperature of the diluent was 4°C for samples to be stored at 4°C or −20°C and room temperature for samples to be stored at 23°C. Solutions of azacitidine (10 or 25 mg/mL) were stored in polypropylene syringes and glass vials at room temperature (23°C), 4°C, or −20°C. The concentration of azacitidine was determined by a validated, stability-indicating liquid chromatographic method in serial samples over 9.6 h at room temperature, over 4 days at 4°C, and over 23 days at −20°C. The recommended expiry date was determined on the basis of time to reach 90% of the initial concentration according to the fastest observed degradation rates (i.e., lower limit of 95% confidence interval).

Results:

Azacitidine degradation was very sensitive to temperature but not storage container (glass vial or polypropylene syringe). Reconstitution with cold sterile water reduced degradation. At 23°C, 15% of the initial concentration was lost after 9.6 h; at 4°C, 32% was lost after 4 days; and at −20°C, less than 5% was lost after 23 days.

Conclusions:

More than 90% of the initial azacitidine concentration will be retained, with 97.5% confidence, if, during the life of the product, storage at 23°C does not exceed 2 h, storage at 4°C does not exceed 8 h, and storage at −20°C does not exceed 4 days. These expiry dates could substantially reduce wastage and cost where the time between doses does not exceed 4 days.     

Stability of Pentobarbital Hydrogel for Rectal Administration in Pediatric Procedural Sedation

Purpose: Pentobarbital is a sedative agent to limit children motion during computed tomography or magnetic resonance imaging (MRI) and ensures the successful completion of the imaging procedure. However, data on rectal drug formulation and its stability in practice are not available. The aim of this study was to formulate and evaluate the stability of a ready-to-use rectal pentobarbital gel. Methods: The formulation consisted of a hydrated gel containing 25 mg/mL of pentobarbital sodium, packaged in 10-mL amber glass bottles and stored at either 22°C to 25°C or 2°C to 8°C. At each predetermined time point, samples were taken for visual inspection, pH measurement, and analysis by a validated stability-indicating high-performance liquid chromatography (HPLC) method. The viscosity parameters of the hydrogel formulation were assessed. Results: The freshly prepared rectal formulations appeared clear, colorless, and particular-free with pH readings of 9.75 to 9.83. Over the 90 days of the study period, there was no significant change in appearance or pH values for all stability samples. The HPLC results confirmed the chemical stability when stored at 2°C to 8°C or at 22°C to 25°C. Conclusion: Pentobarbital hydrogel 25 mg/mL are stable chemically at least 90 days and can be administered to children for an effective and fast sedation.     

Degradation of histamine by Bacillus polymyxa isolated from salted fish products

Histamine is the causative agent of scombroid poisoning, a foodborne chemical hazard. Histamine is degraded by the oxidative deamination activity of certain microorganisms. In this study, eight histamine-degrading bacteria isolated from salted fish products were identified as Rummeliibacillus stabekisii (1 isolate), Agrobacterium tumefaciens (1 isolate), Bacillus cereus (2 isolates), Bacillus polymyxa (1 isolate), Bacillus licheniformis (1 isolate), Bacillus amyloliquefaciens (1 isolate), and Bacillus subtilis (1 isolate). Among them, B. polymyxa exhibited the highest activity in degrading histamine than the other isolates. The ranges of temperature, pH, and salt concentration for growth and histamine degradation of B. polymyxa were 25–37°C, pH 5–9, and 0.5–5% NaCl, respectively. B. polymyxa exhibited optimal growth and histamine-degrading activity at 30°C, pH 7, and 0.5% NaCl in histamine broth for 24 hours of incubation. The histamine-degrading isolate, B. polymyxa, might be used as a starter culture in inhibiting histamine accumulation during salted fish product fermentation.     

Determination of biogenic amines in Korean traditional fermented soybean paste (Doenjang)

Biogenic amines, produced by bacterial decarboxylation of amino acids, have been associated with toxicological symptoms in food products. Twenty-three samples of traditionally available Korean fermented soybean paste samples (Doenjang) were analyzed in order to determine the content of biogenic amines. Amines were extracted with 0.4 M perchloric acid and derivatized with dansyl chloride. Nine biogenic amines were separated from Doenjang samples by high performance liquid chromatography using gradient elution (acetonitrile and ammonium acetate), and detected with spectrophotometric UV–vis detection at 254 nm. The pH value of all the samples was ranged from 4.8 to 6.0, and the strong amino acid decarboxylase activity was found to be in an acidic environment. The mean values of biogenic amines (tryptamine, 2-phenyl–ethylamine, putrescine, cadaverine, agmatine, histamine, tyramine, spermidine and spermine) determined in 23 Doenjang samples were found to be 18.37, 82.03, 70.84, 34.24, 47.32, 26.79, 126.66, 74.41 and 244.36 mg%, respectively. The findings of this study enhance the safety of not only Doenjang but other salted and/or fermented food products.     

Ion-pair compounds of diacerein for enhancing skin permeability in vitro: the compatibility–permeability relationship of counter ion and diacerein

This research aimed to investigate how the relationship between counter ion and diacerein (DCN) exerts an effect on the skin penetration of DCN ion-pair compounds. After the ion-pair compounds were formed by DCN and organic amines with different functional groups, the hydrogen bond of these compounds was confirmed by Fourier-transform infrared (FTIR) spectroscopy and molecular docking. The skin of porcine ears was employed to conduct the in vitro skin penetration, DCN – triethanolamine was the most potential candidate with the Q_24h of 7.89 ± 0.38 µg/cm² among organic amines with different functional groups. Whereas among the homologous fatty amine, the most permeable compound was DCN – lauryl amine with the Q_24h of 11.28 ± 0.48 µg/cm². Molecular simulation was employed to explore the relationship between counter ion and DCN. It was revealed by the bind energy curve that DCN had the strongest compatibility with triethanolamine among organic amines and laurylamine (N₁₂) among fatty amines. It was amazingly found that the in vitro permeation fluxes of DCN ion-pair compounds would increase with enhancing the compatibility of counter ion and DCN. These findings broadened our understanding of how the relationship between drug and counter ion affects the skin penetration of ion-pair compounds.     

Preliminary Investigation of Biogenic Amines in Type I Sourdoughs Produced at Home and Bakery Level

During a survey for isolating sourdough lactic acid bacteria (LAB), 20 dough samples produced at the bakery level (BL) or home-made (HM) were collected. An enzyme-based colorimetric method revealed a total biogenic amines (BAs) concentration in the range 41.4–251.8 ppm for six (three BL and three HM) sourdoughs characterised by unpleasant odours. Eight BAs generally investigated in foods were identified and quantified from these six samples by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS). Only one HM sample contained almost all analysed BAs. Tryptamine was exclusively detected in HM sourdoughs (0.71–24.1 ppm). Putrescine, tryptamine, spermidine, and spermine were the only BAs detected in BL sourdoughs. MiSeq Illumina analysis was applied to study the total bacterial community of sourdoughs. LAB accounted from 67.89 to 92.17% of total bacterial diversity, and Levilactobacillus brevis was identified in all six sourdoughs. Leuconostoc, Pediococcus, and Weissella were also dominant. Plate counts detected neither the presence of Pseudomonas nor members of the Enterobacteriaceae family, and LAB levels were, on average, barely 5.89 Log CFU/g for BL, and 7.33 Log CFU/g for HM sourdoughs. Data suggested that the microorganisms mainly imputable of BAs formation in sourdough are members of the LAB community.     

Stability of Ertapenem 100 mg/mL in Manufacturer’s Glass Vials or Syringes at 4°C and 23°C

Background:

Prophylactic administration of ertapenem as a single 1-g IV dose has been shown to reduce sepsis after prostate biopsy.

Objective:

To evaluate the stability of ertapenem after reconstitution with 0.9% sodium chloride to a final concentration of 100 mg/mL and storage in the manufacturer’s original glass vials or polypropylene syringes.

Methods:

On study day 0, 100 mg/mL solutions of ertapenem were retained in the manufacturer’s glass vials or packaged in polypropylene syringes and stored at 4°C or 23°C without protection from fluorescent room light. Samples were assayed periodically over 18 days using a validated, stability-indicating liquid chromatographic method with ultra-violet detection. A beyond-use date was determined as the time for the concentration to decline to 90% of the initial (day 0) concentration, based on the fastest degradation rate, with 95% confidence.

Results:

Reconstituted solutions stored in the manufacturer’s glass vials or polypropylene syringes exhibited a first-order degradation rate, such that 10% of the initial concentration was lost in the first 2.5 days when stored at 4°C or within the first 6.75 h when stored at room temperature (23°C). Analysis of variance showed differences in the percentage remaining due to temperature (p < 0.001) and study day (p < 0.001) but not type of container (p = 0.98). When a 95% CI for the degradation rate was calculated and used to determine a beyond-use date, it was established that more than 90% of the initial concentration would remain for 2.35 days at 4°C and for 0.23 day (about 5 h, 30 min) at room temperature.

Conclusions:

A 100 mg/mL ertapenem solution stored in the manufacturer’s glass vial or a polypropylene syringe will retain more than 90.5% of the initial concentration when stored for 48 h at 4°C and for an additional 1 h at 23°C.     

Stability of Reconstituted Telavancin Drug Product in Frozen Intravenous Bags

Background and Objective:

Intravenous (IV) infusions of telavancin for injection are generally administered in-hospital, but in some circumstances they may be administered in an outpatient environment. In that setting, antibiotics may be premixed and frozen. This study determined the chemical stability of nonpreserved telavancin in various commonly used reconstitution diluents stored in IV bags (polyvinyl chloride [PVC] and PVC-free) at -20°C (-4°F) without light.

Methods:

Telavancin (750 mg/vial) was reconstituted with 5% dextrose injection USP (D5W) or 0.9% sodium chloride injection USP (NS) to obtain drug solutions at approximately 15 mg/mL. Infusion solutions of telavancin at diluted concentrations of 0.6 mg/mL and 8.0 mg/mL covering the range utilized in clinical practice were prepared in both PVC and PVC-free IV bags using D5W or NS solutions. The infusion solutions were stored under frozen conditions (-20°C ± 5°C [-4°F ± 41°F]) and the chemical stability was evaluated for up to 32 days. Telavancin concentration, purity, and degradant levels were determined using a stability-indicating high-performance liquid chromatography (HPLC) method.

Results:

Telavancin IV infusion solutions in D5W or NS at 0.6 mg/mL and 8 mg/mL and stored at -20°C (-4°F) met the chemical stability criteria when tested on days 0, 7, 14, and 32. The assayed telavancin concentration at each time point was within 97% to 103% of the initial mean assay value. The total degradants quantified by the HPLC stability-indicating method did not show any significant change over the 32-day study period.

Conclusion:

Telavancin IV infusion solutions (in D5W or NS) in both PVC and PVC-free IV bags were stable for at least 32 days when stored at -20°C (-4°F) without light. These results provide prolonged frozen stability data further to that previously established for 7 days under refrigerated conditions (2°C-8°C [36°F -46°F]), and for 12 hours at room temperature when diluted into IV bags containing D5W, NS, or lactated Ringer’s solution.     

Temperature-dependent studies on the total phenolics,flavonoids, antioxidant activities,and sugar content in six onion varieties

Heating effect on total phenol, flavonoids, antioxidant activity, and sugar content of six onion varieties has been quantitatively investigated to explore the effect of different temperatures. The onion varieties comprised one red-skinned variety, two white-skinned varieties, and three yellow-skinned varieties. The heating temperature was scanned at 80°C, 100°C, 120°C, and 150°C for 30 minutes each, and quantitative analysis was performed relative to the powdered onion at ambient temperature. Quercetin, glucosides and sugar content were analyzed using high-performance liquid chromatography. The total phenolic and antioxidant content increased in all six varieties. The total flavonoid levels showed a considerable change. On heating the onion samples at 120°C for 30 minutes, the red-skinned variety showed the highest level of total phenolic content [13712.67 ± 1034.85 μg of gallic acid equivalent/g dry weight (μg GAE/g DW)] and total flavonoids [3456.00 ± 185.82 μg of quercetin equivalents/g dry weight (μg Q/g DW)], whereas the content of total phenolics and total flavonoids were 13611.83 ± 341.61 μg GAE/g DW and 3482.87 ± 117.17 μg Q/g DW, respectively, for the yellow-skinned (Sunpower) variety. Quercetin and its glucoside contents increased up to 120°C and then decreased at 150°C, whereas the sugar content continuously decreased with heating. All cultivars showed the same pattern in the heating effect, and the predominant flavonoids were destroyed at higher temperatures. Therefore, it is improper to expose onion powder to a temperature higher than 120°C.     

Pharmacokinetic Parameters Determination and In Vitro–In Vivo Correlation of Ileocolonic-Targeted pH-Responsive Coated Mini-Tablets of Naproxen

This research work aims to determine the pharmacokinetic parameters and in vitro-in vivo correlation of the selected ileocolonic-targeted coated mini-tablet filled capsule formulation of naproxen. The pure suspension and coated mini-tablet filled capsule formulation of naproxen were administered to adult albino rabbits through the oral route. The samples were analyzed for naproxen by an HPLC method. For the pure drug suspension, the peak plasma concentration was found as 8.499±0.029 μg/ml at 1.139±0.010 hours and the half-life was found to be 9.459±0.387 hours, whereas for the formulation the peak plasma concentration was found as 6.814±0.037 μg/ml at 8.042±0.069 hours and the half-life was found to be 19.657±0.359 hours. This decreased the peak plasma concentration at a delayed time and increased the half-life of the capsule formulation in comparison with the pure drug suspension which showed that naproxen was only targeted to the ileocolonic region. A significant in vitro-in vivo correlation (i.e. R²=0.9901) was also obtained. Thus, the results of these findings suggest that naproxen formulated as coated mini-tablets can be suitable for targeted ileocolonic drug delivery.     

Impacts of Climate Change Interacting Abiotic Factors on Growth,aflD and aflR Gene Expression and Aflatoxin B1 Production by Aspergillus flavus Strains In Vitro and on Pistachio Nuts

Pistachio nuts are an important economic tree nut crop which is used directly or processed for many food-related activities. They can become colonized by mycotoxigenic spoilage fungi, especially Aspergillus flavus, mainly resulting in contamination with aflatoxins (AFs), especially aflatoxin B₁ (AFB₁). The prevailing climate in which these crops are grown changes as temperature and atmospheric CO₂ levels increase, and episodes of extreme wet/dry cycles occur due to human industrial activity. The objectives of this study were to evaluate the effect of interacting Climate Change (CC)-related abiotic factors of temperature (35 vs. 37 °C), CO₂ (400 vs. 1000 ppm), and water stress (0.98–0.93 water activity, a_w) on (a) growth (b) aflD and aflR biosynthetic gene expression and (c) AFB₁ production by two strains A. flavus (AB3, AB10) in vitro on milled pistachio-based media and when colonizing layers of shelled raw pistachio nuts. The A. flavus strains were resilient in terms of growth on pistachio-based media and the colonisation of pistachio nuts with no significant difference when exposed to the interacting three-way climate-related abiotic factors. However, in vitro studies showed that AFB₁ production was significantly stimulated (p < 0.05), especially when exposed to 1000 ppm CO₂ at 0.98–0.95 a_w and 35 °C, and sometimes in the 37 °C treatment group at 0.98 a_w. The relative expression of the structural aflD gene involved in AFB₁ biosynthesis was decreased or only slightly increased, relative to the control conditions at elevated CO, regardless of the a_w level examined. For the regulatory aflR gene expression, there was a significant (p < 0.05) increase in 1000 ppm CO₂ and 37 °C for both strains, especially at 0.95 a_w. The in situ colonization of pistachio nuts resulted in a significant (p < 0.05) stimulation of AFB₁ production at 35 °C and 1000 ppm CO₂ for both strains, especially at 0.98 a_w. At 37 °C, AFB₁ production was either decreased, in strain AB3, or remained similar, as in strain AB10, when exposed to 1000 ppm CO₂. This suggests that CC factors may have a differential effect, depending on the interacting conditions of temperature, exposure to CO₂ and the level of water stress on AFB₁ production.     

Impairment of cognitive function associated with hydroxyamylobarbitone accumulation in patients with renal insufficiency

1. Sodium amylobarbitone was given by intravenous infusion to six patients with chronic renal insufficiency and to six healthy volunteer subjects. Serum concentrations of amylobarbitone and its major metabolite hydroxyamylobarbitone were measured by a gas chromatograph method.

2. The serum concentrations of amylobarbitone were consistently lower in the patient group than in the control group and the concentration half time was shorter (0·10>P>0·05); the 48 h urinary excretion of hydroxyamylobarbitone was reduced (P<0·001) and the serum concentrations of hydroxyamylobarbitone were consistently raised.

3. When two patients were given 200 mg of sodium amylobarbitone daily over five consecutive days the serum concentration of hydroxyamylobarbitone rose steadily to a maximum of about 8 μg/ml. The serum concentrations in two healthy control subjects did not exceed 0·5 μg/ml.

4. Three parallel tests of cognitive function (Otis matched test forms A, B and C) were given to 16 control patients and to 12 amylobarbitone-treated patients. Significant impairment of performance was observed in test B (P<0·001) at a time when amylobarbitone only could be detected in the patients' serum, and in test C (P<0·001) when amylobarbitone concentrations were very low (0·52±0·08 μg/ml±SEM) but hydroxyamylobarbitone concentrations were still high (3·30±1·23, μg/ml±SEM).

5. There was a strong (r=-0·71) and significant (P<0·01) negative correlation between the performance in test C and the serum concentration of hydroxyamylobarbitone. It is concluded that hydroxyamylobarbitone has cerebral depressant effects in man.

     

A validated HPTLC method for determination of terbutaline sulfate in biological samples: Application to pharmacokinetic study

Terbutaline sulfate (TBS) was assayed in biological samples by validated HPTLC method. Densitometric analysis of TBS was carried out at 366 nm on precoated TLC aluminum plates with silica gel 60F₂₅₄ as a stationary phase and chloroform–methanol (9.0:1.0, v/v) as a mobile phase. TBS was well resolved at R_F 0.34 ± 0.02. In all matrices, the calibration curve appeared linear (r² ⩾ 0.9943) in the tested range of 100–1000 ng spot⁻¹ with a limit of quantification of 18.35 ng spot⁻¹. Drug recovery from biological fluids averaged ⩾95.92%. In both matrices, rapid degradation of drug favored and the T_0.5 of drug ranged from 9.92 to 12.41 h at 4 °C and from 6.31 to 9.13 h at 20 °C. Frozen at −20 °C, this drug was stable for at least 2 months (without losses >10%). The maximum plasma concentration (Cp_max) was found to be 5875.03 ± 114 ng mL⁻¹, which is significantly higher than the maximum saliva concentration (Cs_max, 1501.69 ± 96 ng mL⁻¹). Therefore, the validated method could be used to carry out pharmacokinetic studies of the TBS from novel drug delivery systems.