Ispitivanje stabilnosti oralnih suspenzija omeprazola za pedijatrijsku primenu magistralno izrađenih iz omeprazol kapsula

In this paper, a study exploring the stability of omeprazole in pediatric suspensions is presented. In order to determine the most suitable suspension, three different formulations were prepared and stored under refrigerated conditions and at room temperature for 30 days. Contents of omeprazole and preservatives were determined by liquid chromatographic method. Obtained results demonstrate that the vehicle consisting of: xanthan gum 0.3%, sodium bicarbonate 8%, Compound hydroxybenzoate solution APF 1% and purified water to 100% could have a significant potential in the development of a suitable omeprazole oral liquid for pediatric use. Namely, the content of omeprazole in the suspension prepared with this vehicle remained within acceptable range during the 30-day period, when stored refrigerated (2-8°C).U ovom radu predstavljeno je ispitivanje stabilnosti omeprazola u suspenzijama za pedijatrijsku primenu, koje su izrađene iz komercijalno dostupnih kapsula omeprazola u uslovima apoteke. U cilju utvrđivanja najpogodnijeg vehikuluma za magistralnu izradu suspenzija omeprazola, pripremljene su tri formulacije, koje su potom 30 dana čuvane u frižideru i na sobnoj temperaturi. Sadržaj omeprazola i konzervansa u suspenzijama je određivan primenom tečne hromatografije. Dobijeni rezultati ukazuju da vehikulum koji se sastoji iz ksantan gume 0,3%, natrijum-bikarbonata 8%, rastvora parabena 1% (Compound hydroxybenzoate solution APF) i prečišćene vode do 100% ima značajan potencijal za razvoj pogodnog tečnog oblika omeprazola za peroralnu primenu u pedijatrijskoj populaciji. Naime, sadržaj omeprazola u suspenziji pripremljenoj primenom ovog vehikuluma je ostao u okviru prihvatljivih granica tokom perioda od 30 dana, kada je suspenzija čuvana u frižideru (2-8°C)

Systematical approach in evaluation of LC method for determination of raloxifene hydrochloride and its impurities employing experimental design

Method validation presents a detailed investigation of analytical method and provision of the evidence that the method, when correctly applied, produces results that fit to the purpose. In order to achieve the method validation scope efficiently, experimental design presents a very useful tool. The greatest benefits of such approach could be seen in robustness testing through the provision of very useful data about the control of the chromatographic system during the routine application. In this paper, robustness testing of the LC method proposed for the determination of raloxifene hydrochloride and its four impurities was done employing Plackett-Burman design. Applying this design, the effect of five real factors (acetonitrile content, sodium dodecyl sulfate content, column temperature, pH of the mobile phase and flow rate) on the corresponding resolution factors was investigated through twelve experiments. Furthermore, the insignificance intervals for significant factors were calculated and the parameters for system suitability tests were defined. Eventually, the other validation parameters were tested and the effectiveness of the proposed analytical method with a high degree of accuracy was confirmed

Desirability-based optimization and its sensitivity analysis for the perindopril and its impurities analysis in a microemulsion LC system

In the current paper the application of multiobjective optimization (MOOP) technique, via Derringer's desirability function, to a microemulsion liquid chromatographic (MELC) method is described. Chromatographic separation of perindopril tert-butylamine and its four impurities was selected as the case study. Central composite design (CCD) with fractional factorial design, ±. 0.5 α star design and four replications in central point was applied for a response surface study, in order to examine in depth the effects of the most important factors. As factors that influence the system mostly (i) content of ethyl acetate and (ii) butyl acetate in composite internal phase, (iii) content of sodium dodecyl sulfate (surfactant) and (iv) n-butanol (co-surfactant), as well as (v) pH of the mobile phase were selected. Retention factor of (a) perindoprilat and (b) impurity Y 31 and (c) resolution factor for impurities Y 32 and 33 were chosen for simultaneous optimization. By adjustment of the importance coefficients and weights, according to defined objectives, the optimal mobile phase composition was predicted to be: 0.24% w/v butyl acetate, 0.3% w/v ethyl acetate, 2% w/v SDS, 7.75% w/v n-butanol and pH of the mobile phase 3.7. The sensitivity analysis of desirability function for these optimal conditions was conducted for the first time in LC separations, by applying a sensitivity procedure. The performed sensitivity analysis confirmed that the higher overall desirability does not necessarily mean a better solution. The accuracy of prediction might be affected if the optimal levels of input variables, achieved from several design points, end up with equal settings and different corresponding overall desirability. In our study this was not the issue, which confirmed the adequacy of predicted optimum. © 2011 Elsevier B.V

Processing and characterization of UHMWPE composite fibres with alumina particles in poly(ethylene-vinyl acetate) matrix

Processing of hybrid composites represents a challenge for engineers where the aim is to establish compatibility among several materials. The aim of this study is to evaluate the effects of different sizes and morphologies of alumina fillers on the mechanical and thermal properties of the composite fibres based on ultra-high molecular weight polyethylene fibres (UHMWPE). These fibres have an outstanding elastic modulus and they are compatible with nonpolar sequences of the poly(ethylene-co-vinyl acetate) (EVA) matrix. Compared to the fibres, inferior mechanical properties of the matrix can be improved using alumina particles. Commercial aluminium oxide (Al2O3) nanoparticles, commercial whiskers and synthesized particles of Al2O3 doped with iron oxide, incorporated in different weight percentages, were used as fillers. The UHMWPE fibres were impregnated using the solution of EVA in toluene with dispersed particles. Fourier transform infrared spectroscopy and field emission scanning electron microscope were used for structural examination. Tensile testing revealed increasing of modulus of elasticity and strengths of obtained hybrid composite fibres. Thermal gravimetry showed improved thermal stability up to 350 degrees C of the hybrid composite fibres with alumina particles doped with iron oxide. Results of tested samples showed that the best mechanical properties were for hybrid composite fibres with 1 wt% of iron doped alumina filler