Browsing by Subject "validointi"

Cytochrome P450 (CYP) -enzymes are one of the most important enzymes in the metabolism of xenobiotics. Because many xenobiotics are metabolized with each other by the same CYP-enzymes, it is possible that metabolic interactions will take place. These interactions can be the inhibition or induction of the metabolism of another xenobiotic. The interaction can be harmful e.g. when it causes an accumulation of a toxic metabolite or when it inhibits the metabolism of an active drug substance. The aim of this study was to develop a quantitative method for determining metabolic interactions between drugs and environmental chemicals in human liver microsome (HLM) incubations. HLMs contain high concentrations of CYP-enzymes, enabling the use of CYP-model reactions for observing interactions. The model reactions chosen for this study were O-deethylation of phenacetin (CYP1A2), 7-hydroxylation of coumarin (CYP2A6), 4'-hydroxylation of diclofenac (CYP2C9), 1'-hydroxylation of bufuralol (CYP2D6) and 6β-hydroxylation of testosterone (CYP3A4). Michaelis-Menten constants (Km) and maximal enzymatic activities (Vmax) were determined for each model reaction. The suitability of the model reactions for inhibition studies was assessed with specific inhibitors. The quantitative method was developed for an ultra-high performance liquid chormatograph (UPLC) and for a quadrupole time of flight mass spectrometer (QTOF). Samples were ionized with electrospray ionization (ESI) using positive mode. Device parameters were the same for all the metabolites. The analytical method validation was partly performed according to ICH (International Conference on Harmonisation) guidelines. A sufficient linearity (R2>0,99) and specificity was achieved for the quantitative method. The achieved limits of quantitation (LOQ) were low enough (1-120 nM) for quantitation of the small concentrations of the metabolites formed in the inhibition assays. The measurement reproducibility and the reproducibility and accuracy of the method did not fulfill the acceptance criteria for all the metabolites. Improvement of the results should be tried by e.g. exploring different device parameters. 1'-hydroxydiclofenac was found likely to degrade in the matrix solution because of the acidic conditions, making the reliability of the results poor for this metabolite. The Km value obtained for coumarin differed markedly from literature values, which can be due to a too long incubation time. Therefore, incubation conditions should be optimized for this model reaction in coming studies. The Km values obtained for the model reactions of CYP1A2, CYP2D6 and CYP3A4 were similar to those found in literature. Also the IC50 values were quite well within the range of values reported in literature for the inhibitors of the above mentioned model reactions. The effects of four different polymers, F68, F127, Tetronic 1307 and polyvinyl alcohol (PVA) on the enzyme activities were also studied, at a concentration of 1 mg/ml. In principal, at this concentration the polymers did not cause significant changes in the enzyme activities, although inhibition of the CYP2C9 could have been significant. However, the reliability of CYP2C9 model reaction was found to be poor with the used method. In the future this developed method should be further validated, and the incubation conditions for the model reaction of CYP2A6 should be optimized. After this, the IC50 values for the polymers could be studied to get more reliable information about their potential CYP-inhibition properties.

Tablets are solid medicinal products that are produced by compressing tablet mass in a tablet press. The reproducible and reliable functionality of the manufacturing process, facilities and equipment used in the manufacturing process of medicinal products must be validated. There must be a marketing authorisation for the sale of medicinal products, and pharmaceutical companies must comply with current legislation, Good Manufacturing Practices, and other binding guidelines. After marketing authorisation, certain changes, such as significant changes related to the manufacturing process or raw materials, must be notified to the competent authority by means of a variation application. Depending on the extent of the change, a revalidation and/or a regulatory approval before implementing the change may be required, which makes manufacturing process modification slow, expensive, and laborious. However, the pressure to enhance pharmaceutical manufacturing processes and reduce costs is prevailing. In this study, Lean Six Sigma methods were applied to enhance the manufacturing process of a tablet product. The study was divided into two parts. In the first part of the study, the objective was to investigate the manufacturing process of a tablet product X and to identify improvement actions that would make the manufacturing process of the tablet product X more efficient by achieving material and time savings. In addition, improvement actions were prioritized based on the benefits achieved by the improvement actions and the difficulty of implementation. The second part of the study was based on the improvement action selected from the first part of the study. The objective of the second part of the study was to investigate the factors influencing the amount of mass loss during tableting and how the amount of mass loss can be influenced. In this study, mass loss during tableting referred to the dusty mass inside the tablet press during tableting, which is removed from the tablet press to the equipment dedusting system. The purpose of the practical experiment conducted in the tablet production, which was part of the second part of the study, was to investigate how the magnitude of the exhaust airflow and fan power of the equipment dedusting system affects the amount of mass loss generated during tableting. Based on the experiment, adjusting the power of the equipment dedusting system can affect the amount of mass loss generated during tableting. However, further studies are needed to ensure that no dusty mass remains in the piping of the dedusting system or in tablet press at low exhaust airflow and fan power values during tableting. If the results are applied to other tablet products, the effect of a different formulation on powder dusting should be considered. Adequate dedusting during tableting is important so that the dusty mass inside the tablet press is removed as intended, facilitating the cleaning of the tablet press after tableting and reducing the risk of cross-contamination and exposure of workers to dust. The conclusion of this study is that Lean Six Sigma methods can be used more extensively to enhance the manufacturing processes of both tablet products and other pharmaceutical dosage forms and to reduce loss generated during the manufacturing process without revalidation or changes to a valid marketing authorisation.