Tyrimo objektas ir metodai: Thymus spp. genties augalų žolė. Fenoliniai junginiai nustatyti spektrofotometrijos metodais, timolis – efektyviosios skysčių chromatografijos metodu. Darbo tikslas: ištirti čiobrelio žolėje esančių fenolinių junginių kiekio ir laisvųjų radikalų surišimo gebos įvairavimą Lietuvos klimato sąlygomis augančių čiobrelių žolės mėginiuose. Darbo uždaviniai: surinkti čiobrelių žolės žaliavų mėginius skirtinguose Lietuvos regionuose; spektrofotometrijos metodu nustatyti ir įvertinti suminį fenolinių junginių kiekį čiobrelio žolės mėginiuose; spektrofotometrijos metodu nustatyti ir įvertinti čiobrelio genties augalų žolės mėginių antioksidantinį aktyvumą ir jo įvairavimą; ESC metodu nustatyti fitocheminius žymenis, būdingus čiobrelio genties augalams; dendrograminiu modeliu įvertinti čiobrelių genties žaliavų mėginių rezultatus; sugrupuoti individų, rinktų skirtingose augavietėse žaliavų mėginius pasižyminčius fenolinių junginių kiekybiniais skirtumais ir antioksidantinio aktyvumo skirtumais; įvertinti fenolinių junginių kiekybinės sudėties ir laisvųjų radikalų surišimo gebos koreliacinius ryšius Lietuvos klimato sąlygomis augančių čiobrelių žolės mėginiuose. Išvados: Didžiausias suminis fenolinių junginių kiekis nustatytas T. serpyllum žolės mėginiuose rinktuose Molėtuose, Antalieptėje ir Ignalinoje. Mažiausias fenolinių junginių kiekis nustatytas T. serpyllum mėginio rinkto Lazdijų rajone ir T. pulegioides mėginio rinkto Zarasuose. Didžiausia... [toliau žr. visą tekstą] / Object and methods of assay: the object of this assay is Thymus spp. generic herb. Phenolic compounds were estimated by methods of spectrophotometry, where as thymol – by method of effective liquid chromatography. The aim of the work: to estimate variability of the quantity of phenolic compounds and free radical binding activity of thymus herb samples taken from various places in Lithuania with different climatic conditions. The goals of this work: to collect thyme herb samples from various regions in Lithuania; to estimate and evaluate the total amount of phenolic compounds in thyme herb samples by spectrophotometry method; to estimate and evaluate thyme generic herb antioxidant activity and variety in samples by spectrophotometry method; to estimate phytochemical marks, specific for thyme generic herbs by ESC method; to estimate thyme generic herb samples by dendrogram method; to group raw material samples of different individuals from different growing places that have differences in quantity of phenolic compounds and antioxidant activity; to evaluate correlation between structure of quantitative phenolic compounds and free radical binding activity in thyme samples taken from various places in Lithuania with different climatic conditions. Conclusions: The biggest total amount of phenolic compounds was estimated in T. serpyllum herb samples gathered in Moletai, Antaliepte and Ignalina. The smallest amount of phenolic compounds was estimated in T. serpyllum sample... [to full text]

Milk contains high concentrations of calcium. It occurs in two forms, a free ionic form, and calcium associated with milk proteins (caseins). The latter association is called colloidal calcium phosphate. New Zealand Dairy Foods of Takanini is marketing a range of commercial milks in supermarkets. The company uses ultra filtration to concentrate milk proteins and calcium in different milk products. During ultra filtration, the fraction that is retained by the membrane is rich in calcium bound to proteins and the portion that passes through the membrane is richer in the free ionic form. The company wanted to develop a quick and an economical method that can be applied in industrial settings to determine calcium in both these fractions and in other milk products. This research aimed to develop a quick, wet chemistry method to measure calcium in milk fractions and to trial it in an industrial environment. Two methods, the so-called EDTA method and the atomic absorption spectrophotometric method (AA) were trialled as potential reference methods against which to compare results obtained by the method to be developed. The AA method was chosen due to its ease, accuracy and precision. (This could not be selected as the industrial method for a number of reasons.) A colorimetric method was favoured over other contenders. Two colorimetric dyes, Arsenazo I and o-cresolphthalein-complexone (CPC) were chosen to work with. Arsenazo I forms a purple complex with calcium in a suitable buffer at a range of pHs. o-Cresolphthalein-complexone also forms purple-coloured complexes at alkaline pHs. During method development with Arsenazo I, different buffers were trialled and a NaOH/ KCl buffer was selected for further development at pH 12. The method worked well during the development phase but with some inconsistent results at times. o-Cresolphthalein-complexone formed clear purple complexes with Clark and Lubs and 2-amino-2-methylpropanol (AMP) buffers. The key advantage of the CPC dye with AMP buffer was that when 8-hydroxyquinoline was included in the reaction mixture, it successfully masked coloured complex formation due to CPC with magnesium, which is present in milk at about 1/3 the calcium concentration. This effect did not work with Arsenazo I. However, the results obtained with the CPC method were lower than claimed values of most milks trialled during development. Both methods were compared for their precision and it was found that CPC method has better precision and was chosen for further development. To improve the accuracy and precision, various denaturing reagents were used to (hypothetically) release calcium from the caseins. Trichloroacetic acid at 25 % was more effective than the several other denaturing treatments tested. The finalised CPC method, using trichloroacetic acid, AMP and 8-hydroxyquinoline, was then used to monitor calcium concentration over four months in three milk products, skim, Xtra (retentate) and permeate. For all milks, the CPC values were lower than the AA reference values, and the values reported by a commercial analytical laboratory. The reasons for this are discussed, as are other changes in calcium concentration in the three milks throughout the trial. The correlation between the CPC and AA values was poor for Xtra, better for skim, and best for permeate. A chemical model to explain this is discussed. The method developed is cheap and quick, and sample and reagent preparation is simple. The method could be applied in an industrial environment, but a proportionality factor would have to be applied to account for the difference in mean values between the CPC and AA methods.

Milk contains high concentrations of calcium. It occurs in two forms, a free ionic form, and calcium associated with milk proteins (caseins). The latter association is called colloidal calcium phosphate. New Zealand Dairy Foods of Takanini is marketing a range of commercial milks in supermarkets. The company uses ultra filtration to concentrate milk proteins and calcium in different milk products. During ultra filtration, the fraction that is retained by the membrane is rich in calcium bound to proteins and the portion that passes through the membrane is richer in the free ionic form. The company wanted to develop a quick and an economical method that can be applied in industrial settings to determine calcium in both these fractions and in other milk products. This research aimed to develop a quick, wet chemistry method to measure calcium in milk fractions and to trial it in an industrial environment. Two methods, the so-called EDTA method and the atomic absorption spectrophotometric method (AA) were trialled as potential reference methods against which to compare results obtained by the method to be developed. The AA method was chosen due to its ease, accuracy and precision. (This could not be selected as the industrial method for a number of reasons.) A colorimetric method was favoured over other contenders. Two colorimetric dyes, Arsenazo I and o-cresolphthalein-complexone (CPC) were chosen to work with. Arsenazo I forms a purple complex with calcium in a suitable buffer at a range of pHs. o-Cresolphthalein-complexone also forms purple-coloured complexes at alkaline pHs. During method development with Arsenazo I, different buffers were trialled and a NaOH/ KCl buffer was selected for further development at pH 12. The method worked well during the development phase but with some inconsistent results at times. o-Cresolphthalein-complexone formed clear purple complexes with Clark and Lubs and 2-amino-2-methylpropanol (AMP) buffers. The key advantage of the CPC dye with AMP buffer was that when 8-hydroxyquinoline was included in the reaction mixture, it successfully masked coloured complex formation due to CPC with magnesium, which is present in milk at about 1/3 the calcium concentration. This effect did not work with Arsenazo I. However, the results obtained with the CPC method were lower than claimed values of most milks trialled during development. Both methods were compared for their precision and it was found that CPC method has better precision and was chosen for further development. To improve the accuracy and precision, various denaturing reagents were used to (hypothetically) release calcium from the caseins. Trichloroacetic acid at 25 % was more effective than the several other denaturing treatments tested. The finalised CPC method, using trichloroacetic acid, AMP and 8-hydroxyquinoline, was then used to monitor calcium concentration over four months in three milk products, skim, Xtra (retentate) and permeate. For all milks, the CPC values were lower than the AA reference values, and the values reported by a commercial analytical laboratory. The reasons for this are discussed, as are other changes in calcium concentration in the three milks throughout the trial. The correlation between the CPC and AA values was poor for Xtra, better for skim, and best for permeate. A chemical model to explain this is discussed. The method developed is cheap and quick, and sample and reagent preparation is simple. The method could be applied in an industrial environment, but a proportionality factor would have to be applied to account for the difference in mean values between the CPC and AA methods.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Linköping : Univ., 2004. / Härtill 6 uppsatser.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv., 2003. / Härtill 7 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2006. / Härtill 5 uppsatser.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2006. / Härtill 5 uppsatser.

Azithromycin (AZ) is a macrolide antibiotic derivate from erytromycin. AZ has a broad spectrum of activity against common gram-negative pathogens and has been used for the treatment of respiratory tract infection, skin infections and sexually transmitted diseases. In the Brazilian market AZ is available as tablets, compounded capsules and powder for oral suspension. The official methods for the assay of AZ in bulk form; capsules and powder for oral suspension are high performance liquid chromatography or microbiological diffusion assay. No monographs are reported in the pharmacopoeias for AZ evaluation in tablets. In this work two spectrophotometric methods were developed and validated for AZ analysis in tablets and powder for oral suspension. The first method was based on the reaction of AZ with concentrated sulfuric acid (98 % w/v), with detection at 226 nm. The other method was based in the charge-transfer reaction of the drug with s-acceptor iodine, with detection at 363 nm. Both methods showed good linearity (r>0.99), precision (CV<5%) and accuracy (>99%). The results obtained with the proposed methods were in good agreement with those obtained by microbiological diffusion agar method. The optimization of dissolution test conditions for in vitro quality control of AZ in tablets was also studied. The use of 900 mL of 0.1N HCl at 37.0 ± 0.5 ºC, paddle as apparatus, at a stirring rate of 50 rpm, provided satisfactory results for tested products. The percent dissolution of AZ in the established condition was more than 90% in 45 minutes. The validated spectrophotometric method used to evaluate the dissolution testing showed to be specific (with no interference of the placebo or tablets in the quantification of AZ), linear (r>0.99), precise (RSD<5%) and accurate (>97%). The drug showed satisfactory stability in the selected dissolution medium / Azitromicina (AZ) é um antibiótico macrolídeo derivado da eritromicina. AZ apresenta um grande espectro de atividade contra patógenos Gram negativos comuns e tem sido utilizada para o tratamento de infecções do trato respiratório, infecções da pele e doenças sexualmente transmissíveis. No mercado brasileiro a AZ está disponível na forma de comprimidos, cápsulas manipuladas e pó para suspensão oral. Os métodos oficiais para o doseamento de AZ como matéria-prima; cápsulas e pó para a suspensão oral são a cromatografia líquida de alta eficiência ou o método microbiológico de difusão em ágar. Não existem monografias em farmacopéias para avaliação de AZ em comprimidos. Neste trabalho dois métodos espectrofotométricos foram desenvolvidos e validados para a análise de AZ em comprimidos e em pó para suspensão oral. O primeiro método foi baseado na reação de AZ com ácido sulfúrico concentrado (98%, p/v), com detecção em 226 nm. O outro método foi baseado na reação de complexo de transferência de carga do fármaco com o s-aceptor iodo, com detecção em 363 nm. Ambos os métodos mostraram linearidade (r>0,99), precisão (CV<5%) e exatidão (>99%). Os resultados obtidos com os métodos propostos estavam de acordo com aqueles obtidos com o método microbiológico de difusão em ágar. A otimização das condições do teste de dissolução para o controle de qualidade in vitro de AZ em comprimidos foi também estudado. O uso de 900 mL de HCl 0,1N, a 37 ºC ± 0,5 ºC, aparato pá, a um a velocidade de 50 rpm, demonstrou resultados satisfatórios para produtos testados. A percentagem de dissolução de AZ na condição estabelecida foi superior a 90% em 45 minutos. O método espectrofotométrico validado para avaliar a dissolução mostrou-se específico, sem interferência do placebo dos comprimidos, na quantificação de AZ, linear (r>0.99), preciso (CV< 5%) e exato (>97%). O fármaco mostrou estabilidade satisfatória no meio de dissolução selecionado