Novel variants and haplotypes of human flavin-containing monooxygenase 3 gene associated with Japanese subjects suffering from trimethylaminuria.

1. Flavin-containing monooxygenase 3 (FMO3) in humans is polymorphic in several ethnic groups, including Caucasians, Africans and Asians. Some FMO3 variants are associated with a disorder trimethylaminuria. 2. In the current study, we used the results from urinary phenotyping assays to identify 63 subjects with <85% FMO3 metabolic capacity with respect to trimethylamine N-oxidation among 787 Japanese volunteers with self-reported trimethylaminuria. The 63 subjects with reduced FMO3 activity were screened and investigated in detail to identify novel FMO3 variants. 3. Homozygous or heterozygous individuals for new single nucleotide substitution variants/haplotypes p.(Pro282Leu), p.[(Glu158Lys; Glu308Gly; Thr329Ala)], p.[(Glu158Lys; Glu308Gly; Asp429Gly)], p.[(Val257Met; Leu473Pro)], p.[(Glu158Lys; Glu308Gly; Ile441Thr)], and p.[(Arg205Cys; Gly503Arg)] were identified in six proband subjects and their family members after pedigree analyses. 4. These variant FMO3 proteins recombinantly expressed in Escherichia coli membranes exhibited decreased N-oxygenation activities toward trimethylamine (Vmax/Km < 40% that of the wild-type). 5. Although the allele frequencies of the six new variants and/or haplotypes were low, the present results indicated that individuals homozygous or heterozygous for any of these novel missense FMO3 variants or known nonsense mutations such as p.(Cys197Ter) or p.(Arg205Cys) highly found in this self-reported Japanese trimethylaminuria cohort may have reduced FMO3 activity with respect to the N-oxygenation of trimethylamine.

[Effect of lidocaine gargling on taste perception].

Because stomatitis is a painful condition, gargling with lidocaine is often prescribed before meals. However, because lidocaine inhibits nerve conduction, lidocaine gargling may affect taste perception. Therefore, we studied the effects of lidocaine gargle on taste. We prepared samples of the 5 basic tastes at equivalent concentration levels in terms of the taste quotient. We conducted sensory tests to judge whether the samples could be tasted, and the threshold concentrations (50% taste rate) were estimated from the taste rates. The sensory test was repeated after the subjects gargled with lidocaine, and the efficacy ratio was calculated by comparing the threshold concentrations. Although no interaction was observed between the lidocaine gargle and the threshold concentration levels in the logistic regression analysis, significant differences were observed in the primary effects of each standard, such as the concentration levels, flavor, and bitterness. When the efficacy ratios based on the threshold values were calculated, increases in the thresholds for flavor and bitterness were observed. The results of this study suggested that gargling with lidocaine before a meal increases the thresholds for the appreciation of flavor and bitterness. This increase in the threshold values due to lidocaine was associated not with the pharmacological effect of the drug but with its strong bitterness.

Bitterness suppression of the Kampo medicine 'Orengedokuto' using flavoured jellies.

The purpose of this study was to evaluate the effect of various flavoured jellies on the palatability and bitterness of the Kampo medicine 'Orengedokuto', using human gustatory sensation testing. In the gustatory sensation test, eight items were evaluated according to the semantic differential (SD) method and four taste intensities (sweetness, astringency, sourness, and bitterness) were determined. Factor analysis of the results identified two main factors 'Disagreeable taste' and 'Agreeable taste and odour' as predominantly determining the palatability of Orengedokuto. To investigate the influence of jelly odour, evoked images were obtained for five fundamental tastes after smelling jellies. The inhibitory effect of the jelly odour on the bitterness of Orengedokuto was found to be small. When the influence of the various jellies on the disagreeable taste of Orengedokuto was investigated, the bitterness intensities of Orengedokuto mixed with chocolate or strawberry-chocolate jelly were found to be significantly lower than the bitterness of the control. The bitterness intensity of Orengedokuto was found to be significantly and negatively correlated with sweetness intensity using simple linear regression analysis. These results suggest that the sweetness intensity of various jellies inhibits the bitterness intensity of Orengedokuto.

Prediction of incompatibility of ceftriaxone sodium with calcium ions using the ionic product.

The purpose of this study was to evaluate the incompatibility of ceftriaxone sodium with calcium-containing products using the ionic product of precipitation, and the measurement of insoluble microparticles using a light obscuration particle counter. Appropriate volumes of 2% (w/v) calcium chloride solution were added to 0.4-2 mg/ml ceftriaxone isotonic sodium chloride solution, to make solutions with a final calcium ion concentration of 1.25 mmol/l. The solutions were gently agitated and stored at 37 degrees C for 24 h. The number of insoluble microparticles with a diameter less than 10 microm in the mixed sample solution, determined using a light obscuration particle counter, was increased when the ceftriaxone concentration was > or =0.8 mg/ml. The Saturation Index (defined as the ratio of the ionic product to the solubility product constant) of the prepared mixed solution was 1.1. A white precipitate could be observed visually when the ceftriaxone concentration of the sample solution was 7 mg/ml; the Saturation Index of the solution was 9.7. The effect of the calcium source on incompatibility with ceftriaxone sodium was also evaluated. The numbers of insoluble microparticles in sample solutions made by adding calcium chloride to the sample were significantly higher than those made by adding calcium gluconate. These results suggest that ceftriaxone should not be co-administered with calcium-containing products even if no precipitation is observed visually. There will still be insoluble microparticles caused by incompatibility in the sample solution when the Saturation Index of the solution is over 1.0.

Incompatibility of ceftriaxone sodium with calcium-containing products.

The purpose of this study was to evaluate the incompatibility of ceftriaxone with calcium-containing products, which had been the subject of an ALERT issued by the FDA. The influence of calcium ion concentration, storage temperature and shaking on the appearance and quantity of insoluble microparticles in mixtures of the two was examined using a light obscuration particle counter and a stereomicroscope. Appropriate volumes of 2% (w/v) calcium chloride solution were added to ceftriaxone sodium for injection (10 mg/ml) to make solutions with final calcium ion concentrations of 0.5-2.5 mmol/l, and stored at 20 degrees C, 25 degrees C, or 30 degrees C. The number of insoluble microparticles increased on storage when the calcium ion concentration of the sample was > or =2 mmol/l; it exceeded the permissible range at all temperatures by 1 h. The microparticles had a greater diameter at higher temperatures, although fewer microparticles were observed. The weight of precipitate increased as a function of both the calcium ion concentration and the temperature. The number of microparticles was also significantly increased by shaking. The number of microparticles in mixtures containing 1000 microg/ml ceftriaxone was significantly increased, even though concentrations of calcium ion was 1.25 mmol/l. Overall, not only calcium ion concentration, but storage temperature and shaking affected the extent of precipitation of ceftriaxone with calcium.

The taste sensory evaluation of medicinal plants and Chinese medicines.

The purpose of this study was to investigate the use of the artificial taste sensor in the evaluation of 11 medicinal plants and 10 Chinese medicines with bitter and/or astringent tastes, and to assess the possible application of the sensor in the evaluation of taste and quality control of medicinal products. Aqueous extracts of the six bitter medicinal plants could be classified into three types, and those of the five astringent medicinal plants into two types, on the basis of sensor output pattern profiles. These differences seem to derive from the different structures of the main components. In the principal component analysis of the taste sensor output of 10 Chinese medicines, a new measure developed, the 'Euclidean distance', defined as the distance between a control and the targeted substance on the principal component map. This measure offers a possibility for indicating the different tastes of Chinese medicines. Lastly, we confirmed that berberine adsorption on the surface of the artificial membrane of the taste sensor was of the Langmuir type. The berberine content in extracts of medicinal plants could be evaluated by the taste sensor, and it was shown to be possible to use the taste sensor for the quality control of medicinal plants.

Evaluation of the taste and smell of bottled nutritive drinks.

The purpose of this study was to evaluate the palatability of 15 bottled nutritive drinks, all commercially available in the Japanese market, using data from artificial taste and odor sensors. In gustatory sensation tests, well-trained healthy volunteers were asked to score the drinks in terms of palatability and of the four basic tastes. The results suggest that overall palatability is positively correlated with sourness intensity and fruitiness (R=0.82 and 0.86, respectively) and negatively correlated with bitterness intensity and the tasting of medicinal plants (R=-0.85 and -0.80, respectively). The sourness and bitterness intensity could be predicted by taste sensor and fruitiness could be predicted by odor sensor, respectively. By performing principal component analysis of the taste sensor data, the 15 drinks could be classified into four groups. The group classified as being predominantly sour had the highest palatability score, 3.8. By principal component analysis of odor sensor data, the drinks could also be classified into four groups and this time the group with a fruity flavor (smell) showed the highest palatability score, 3.4. In the combined analysis of both taste and odor data, products containing medicinal plants showed the lowest palatability. Finally, the combined usage of the taste and odor sensors gave rise to a three-group classification. Thus, not only the taste sensor but also the odor sensor may be useful in evaluating the palatability of bottled nutritive drinks.

Famotidine orally disintegrating tablets: bitterness comparison of original and generic products.

The purpose of the present study was to compare the palatability of the original and eight generic versions of famotidine orally disintegrating tablets by means of human gustatory sensation tests, a comparison of the release profiles, and using an automated taste sensor, the alpha-Astree Electronic Tongue. In the gustatory sensation test, the original product (Gaster D, 10 mg) showed the lowest bitterness intensity. Among the eight generic products tested, the variance in the sweetness intensity was not great, but there were large variances in the intensity of bitterness, some of the generic products being significantly more bitter than that of the original product. On the other hand, some generic products show similar bitterness level as the original product. In a study of release profiles, the original product had the lowest release rates of both famotidine and aspartame; in comparison, some of the generic products had high release rates of famotidine and aspartame, even in the initial stages. Whereas some generic products had low release rates of famotidine and aspartame. Finally, sample solutions were analysed using the taste sensor. There was a good correlation between the taste predicted by principal component analysis and the Euclidean distance obtained by the taste sensor, and bitterness intensities obtained in the human gustatory tests.

Quality of twelve clarithromycin dry syrup formulations-bitterness, grittiness and uniformity of drug loading.

The objective of the study was to evaluate the bitterness, grittiness and uniformity of drug loading as measures of the quality of 12 formulations of clarithromycin dry syrup (CAMDS), comprising one branded and 11 generic products. Some of the generic CAMDS formulations were more bitter than the branded product while others had similar bitterness when tested as aqueous suspensions. Only one generic product was less bitter than the branded product when tested as a suspension in acidic sports drink. The usual dissolution test described in JP XV could not be used to evaluate the bitterness of the products. A brief dissolution test using only 12.5 ml of water was used to evaluate the bitterness of the products in aqueous suspensions. There were considerable variances in the grittiness of the various products, which were independent of particle size. Changes in grittiness level seemed to be correlated with changes in the intensity of bitterness due to the disintegration of the formulation. Finally, there was less variation in the uniformity of drug loading for the branded product than for the generic products. These data may be useful when selecting which CAMDS formulation to prescribe.

Suppression of bitterness and improvement of palatability of commercial prednisolone powder.

The aim of the study was to suppress the bitterness and improve the palatability of pediatric prednisolone powder (PP) by the addition of simple sucrose syrup (SS) and various beverages and foods. Bitterness suppression was evaluated using the human gustatory sensory test. The suppression of the bitterness and improvement of palatability of PP by addition of SS solutions was investigated using standard taste substances: sucrose for sweetness, tartaric acid for sourness, and sodium chloride as saltiness. Dilution with SS solutions of up to 50% (w/w) was successful in bitterness-suppression and improvement of palatability, but at 80% (w/w) SS, the palatability of the diluted solution was reduced. The kinematic viscosities of SS solutions were therefore evaluated using the Uberorde viscosity meter, to see whether the high viscosity of the more concentrated solutions was responsible for the reduced palatability. The kinematic viscosity of the 80% SS was 16.60 mm(2)/s. Judging from above information, the palatability might become worse when the kinematic viscosity of syrup exceeded 15 mm(2)/s. Finally, the ability of various beverages and foods with low viscosity to suppress the bitterness and improve the palatability of PP were examined. The additions of orange juice or a carbonated lemon drink to simple syrup solution were most effective in suppressing bitterness and improving palatability of PP.

Inhibitory effect of aroma on the bitterness of branched-chain amino acid solutions.

Nutritional products for patients with liver failure available on the Japanese market contain many branched-chain amino acids (BCAAs) such as L-leucine, L-isoleucine, and L-valine, which not only have a bitter taste but also strong, unpleasant odours, leading to low palatability. The palatability of these nutritional products can be significantly improved by the addition of flavoured powders containing various kinds of tastants (sucrose, citric acid, etc.) and odourants (fruit, coffee aromas, etc.). The specific effects of the aroma of flavoured powders have not yet been clearly evaluated. In the present article, the inhibitory effect of aroma on the bitterness of BCAA solutions was examined. The bitterness intensity of a BCAA solution at the same concentration as Aminoleban EN was defined as 3.5 (measured by a previously described gustatory sensation method). The bitterness threshold of a BCAA standard solution without added aroma was estimated to be 1.87, while those of BCAA solutions containing green-tea, coffee, apple, vanilla, or strawberry aromas were 2.02, 1.98, 2.35, 2.40 and 2.87, respectively, when evaluated by the probit method. This shows that the addition of an aroma can elevate the bitterness threshold in human volunteers. The green-tea and coffee aromas predominantly evoked bitterness, while the vanilla aroma predominantly evoked sweetness. Apple and strawberry aromas evoked both sweetness and sourness, with the apple aroma having stronger sourness and the strawberry aroma stronger sweetness. Thus, a 'sweet' aroma suppresses the bitterness of BCAA, with coexisting sourness also participating in the bitterness inhibition.

The quantitative prediction of bitterness-suppressing effect of sweeteners on the bitterness of famotidine by sweetness-responsive sensor.

The purpose of the present study was the quantitative prediction of the bitterness-suppressing effect of sweeteners (sucrose or sugar alcohols) on the bitterness of famotidine (or quinine sulfate as control) solutions using an artificial taste sensor. Firstly, we examined the response characteristics of the sensor response to sweetness. The sensor membrane is charged negatively in the presence of sweeteners, which tend to receive protons from one of the components of the sensor membrane. The magnitude of the sensor response was shown to increase in direct proportion to the concentration of the sweetener. Secondly, we used direct or indirect methods to evaluate and predict the bitterness-suppressing effect of sweeteners on 1 mg/ml famotidine and 81.4 microM quinine sulfate solutions. In direct method, a regression between the sensor output of the sweetness-responsive sensor and the bitterness intensity obtained in human gustatory tests of famotidine solutions containing sweeteners at various concentrations, was performed. As a result, we were able to predict directly the bitterness intensity of the mixed solution. Finally, we also evaluated the bitterness intensity of the dissolution media of commercially available, orally disintegrating tablets containing famotidine by the combined usage of bitterness- and sweetness-responsive sensor. We found that the sugar alcohols in the tablet seem to be effective in the bitterness-suppression of famotidine from these tablets, especially in the initial phase (within 30 s) of the disintegration process.

The suppression of enhanced bitterness intensity of macrolide dry syrup mixed with an acidic powder.

The aim of the present study was to identify a medicine which strongly enhanced the bitterness of clarithromycin dry syrup (CAMD) when administered concomitantly and to develop a method to suppress this enhanced bitterness. The bitterness enhancement was evaluated not only by gustatory sensation tests but also using pH and taste sensor measurements of the mixed sample. A remarkable bitterness enhancement was found when CAMD was mixed with the acidic powder L-carbocysteine. The acidic pH (pH 3.40) of the suspension made from these two preparations, seemed to be due to enhanced release of clarithromycin caused by the dissolution of the alkaline polymer film-coating. Several methods for preventing this bitterness enhancement were investigated. Neither increasing the volume of water taken with the mixture, nor changing the ratio of CAMD:L-carbocysteine in the mixture, were effective in reducing the bitterness intensity of the CAMD/L-carbocysteine mixture. The best way to achieve taste masking was to first administer CAMD mixed with chocolate jelly, which has a neutral pH, followed by the L-carbocysteine suspension. Similar results were obtained for the bitterness suppression of azithromycin fine granules with L-carbocysteine. The chocolate jelly will be useful for taste masking of bitter macrolide drug formulations, when they need to be administered together with acidic drug formulations.

Bitterness suppression of BCAA solutions by L-ornithine.

The purpose of the present study was to evaluate the bitterness-suppressing effect of L-ornithine (L-Orn) on single or mixed solutions of branched-chain amino acids (BCAAs) using human gustatory sensation tests and an artificial taste sensor. The BCAAs tested (L-isoleucine (L-Ile), L-leucine (L-Leu), and L-valine (L-Val)) are the main components of various enteral nutrients or supplements. The bitterness-suppression effect of L-Orn was also compared with the effect of L-Arg. L-Orn was effective in suppressing the bitterness of single or mixed solutions of BCAAs in human gustatory sensation tests, the effect being similar to or greater than that of L-Arg. The artificial taste sensor was able to predict the bitterness-suppressing effects of L-Orn and L-Arg. The response electric potential patterns of L-Val, L-Leu and L-Ile solutions to which 100 mM L-Arg had been added were quite similar to the sensor response patterns of the 100 mM L-Arg solutions alone. The relative response electric potential patterns of L-Val, L-Leu or L-Ile solutions containing 100 mM L-Orn in channels 5-8 (positively charged) are similar to that of single solution of 100 mM L-Orn.