Addendum to Food Additives and Contaminants 2002, 19, 492-501 migration of monomers from liquid crystalline poly(p-hydroxybenzoic acid-co-2-hydroxy-6-naphthoic acid).

Liquid-crystalline co-polyesters (e.g. a random copolyester based on p-hydroxybenzoic acid (HBA) and 2-hydroxy-6-naphthoic acid (HNA) known as Vectra A950) offer good barrier properties, but for food-contact use they require overall and specific migration testing. For Vectra A950 films, the highest overall migration level obtained was 2.3 mg x dm(-2) (13.8 mg x kg(-1)) in olive oil (10 days at 40 degrees C), well below the EC limit of 10 mg dm(-2) (60 mg x kg(-1)). The highest specific migration of HBA was 15.2 microg x dm(-2) (91.2 microg x kg(-1)) in olive oil (2 h at 175 degrees C). In this case, the migration level was well below the EC limit of 10 mg dm(-2) (60 mg x kg(-1)). For HNA, the highest value obtained was 4.3 microg x dm(-2) (26 microg x kg(-1)) in 10% ethanol (4 h at 100 degrees C), well below the specific migration limit (SML = 50 microg x kg(-1)). The results obtained shows that even at these severe conditions, the migration values comply with the new European Union Directive 2002/72/EC, which regulates plastic materials and articles for food contact use. In addition, the polymer Vectra A950 complies with Food Contact Notification (FCN) No. 103 of the United States Food and Drug Administration (FDA). Vectra A950 is therefore permitted for food-contact use both in the European Union and the USA.

Migration of monomers from liquid crystalline poly(p-hydroxybenzoic acid-co-2-hydroxy-6-naphthoic acid).

Liquid-crystalline co-polyesters (e.g. a random copolyester based on p-hydroxybenzoic acid (HBA) and 2-hydroxy-6-naphthoic acid (HNA) known as Vectra A950) offer good barrier properties, but for food-contact use require overall and specific migration testing. For Vectra A950 films, the highest overall migration level obtained was 2.3 mg kg(-1) in olive oil (10 days at 40 degrees C) well below the EC limit of 60 mg kg(-1). The highest specific migration for p-hydroxybenzoic acid was 15.2 microg dm(-2) in olive oil (2h at 175 degrees C). For 2-hydroxy-6-naphthoic acid, the highest value obtained was 4.3 microg dm(-2) in 10% ethanol (4h at 100 degrees C), although it was not on the EC positive and cannot yet be used for food-contact materials. At conditions considered as severe, the estimated daily intake for p-hydroxybenzoic acid was calculated as 11.9 microg/person day(-1) and for 2-hydroxy-6-naphthoic acid it was 5.3 microg/person day(-1). The results exceed the threshold of regulation of 1.5 microg/person day(-1).

Elimination of theobromine metabolites in healthy adults.

The metabolism of theobromine (TB) (500 mg per os) was determined by measuring plasma and saliva concentrations of TB and its metabolites 0-24 h after the load, and urinary excretion 0-48 h after the load. TB and its six metabolites were separated and quantified by combining high performance liquid chromatography and capillary electrophoresis. The urine analyses showed that unchanged TB accounted for 21 +/- 4% (mean +/- SD) of total excretion, the remainder being 7-methylxanthine (7-X, 36 +/- 5%), 3-methylxanthine (3-X, 21 +/- 4%), 6-amino-5[N-methylformylamino]-1-methyluracil (6-AMMU, 11 +/- 4%), 7-methyluric acid (7-U, 10 +/- 2%), 3,7-dimethyluric acid (3,7-U, 1.3 +/- 0.6%) and 3-methyluric acid (3-U, 0.5 +/- 0.4%). In addition to TB, 7-X and 3-X were consistently found in plasma and saliva; 6-AMMU and 7-U were found in plasma and saliva at concentrations < or = 2 mumol l-1 and 0.2 mumol l-1, respectively. TB concentrations in plasma and saliva were similar, whereas the saliva concentrations for 7-X and 3-X were found to be 63 +/- 17% of the plasma concentrations for 7-X and 74 +/- 13% for 3-X, respectively. The high urinary-to-plasma concentration ratio of 7-U (200-300) suggests high excretion of 7-U by the kidneys. Excretion of 7-X, 3-X and 6-AMMU was also high (urinary-to-plasma concentration ratio 45-150), whereas the excretion of TB was significantly lower than its metabolites (urinary-to-plasma concentration ratio 4-6). N3-demethylation of TB accounted for 58 +/- 7% of the urinary metabolites, N7-demethylation for 27 +/- 6%, C8-oxidation of 7-X for 22 +/- 4%, C8-oxidation of 3-X for 2 +/- 2% and formation of 6-AMMU for 13 +/- 4%. The ratio of N3- to N7-demethylation of TB remained constant during the load, but the large interindividual variation observed in ratio makes it unsuitable as a function test for evaluation of liver disease.