RESUMEN
Migration of plasticizers from film coating polymers towards the core and to the storage medium could result in serious changes in the mechanical properties and permeability of coatings thus greatly influencing rate and extent of drug release. The purpose of the present study was to follow the migration of water soluble triethyl citrate applied as a plasticizer in Acryl-Eze coating by Gas Chromatography/Mass Spectrometry (GC/MS). 20%w/w Acryl-Eze dispersions containing triethyl citrate of different concentrations were prepared. Placebo tablets were compressed and coated with the prepared dispersions. The coated tablets were stored under different relative humidity conditions for different time intervals. Considerable migration of triethyl citrate towards the tablet cores was found. The extent of the triethyl citrate migration was influenced by the relative humidity of the storage medium.
Asunto(s)
Citratos/química , Plastificantes/química , Polímeros/química , Composición de Medicamentos , Humedad , Comprimidos RecubiertosRESUMEN
The aim of the present study was to determine by gas chromatography/mass spectrometry (GC/MS) the content uniformity of single theophylline microcapsules of different particle size ranges. Microencapsulation was carried out in a laboratory fluidized bed system using Eudragit L30D aqueous dispersion. Scanning electron microscopy was applied for the characterization of the surface morphology of the prepared theophylline microcapsules of two different particle size ranges. The theophylline content of single particles was determined by GC/MS analysis. It was found that the particle size of microcapsules greatly influenced their theophylline content. The GC/MS analysis was successully applied to indicate the changes in the content uniformity and thus the interparticular costing distribution of single theophylline microcapsules in the presence of several excipients.
Asunto(s)
Teofilina/análisis , Calibración , Cápsulas , Excipientes , Cromatografía de Gases y Espectrometría de Masas , Microscopía Electrónica de Rastreo , Tamaño de la PartículaRESUMEN
Clinical studies confirm that intake of folate, vitamin B6 and B12 above the current recommended dietary allowance is of great significance in the primary prevention of coronary heart disease. In order to fulfill the ever increasing requirements concerning the external appearance, reproducible production of medicines and to decrease the time necessary for the preformulation and formulation experiments, I selected methods which enabled rational experimental design and fast objective evaluation. The objective of my thesis was to formulate tablets containing folic acid, vitamin B6 and B12 of optimal therapeutic concentration and of required stability in the presence of novel excipients applied in direct compression. In the course of my preformulation work thermoanalytical (DTG, DSC), chromatographic (HPLC) and spectrometric (NIR) methods were applied. Destabilizing interactions were evaluated with directly compressible excipients, like Ac-Di-Sol, Cellactose, Tablettose, Avicel PH101, Ludipress. Interactions were detected in the 1 + 1 physical mixtures of vitamins and excipients containing lactose (Cellactose, Ludipress, Tablettose) and their destabilizing effect was confirmed. The results of preformulation studies enabled detection of drug-excipients interactions and selection of compatible excipient system to the given drug composition to formulate dosage form of required stability, processability and effectiveness.