ABSTRACT
The occurrence of deoxynivalenol [DON] in retail foods in Tehran [Iran] was determined using high-performance liquid chromatography technique and immunoaffinity column as the clean-up step. A method was validated for analysis of DON in rice, bread, puffed corn snack and wheat flour. The average recoveries and precision [RSD] for DON in different foods ranged 84.2-93.1% and 2.9-12.0%, respectively. A survey of DON was performed on the 72 samples of rice, bread, puffed corn snack, and wheat flour collected from Tehran retail market. The data showed that 10 samples [13.9%] out of 72 samples were contaminated with DON with the maximum level of 368.7 ng/g. The samples had contamination level lower than the maximum tolerated level of DON in foods in Iran. The total intake of DON was under the provisional maximum tolerable daily intake set for DON by the JECFA
ABSTRACT
Clarithromycin [CLA], a broad-spectrum macrolide, is a poorly soluble drug with dissolution rate limited absorption. The aim of this investigation was to prepare CLA nanoparticles from a ternary ground mixture in the presence of sodium lauryl sulfate [SLS] and poly vinyl pyrrolidone [PVP] as co-grinding water-soluble compounds, in order to improve the drug dissolution rate. Different weight ratios of CLA: SLS: PVP were ground in a dry process by planetary ball mill using different grinding ball size. Following the dissolution rate study, physical properties of the best dissolved co-ground formulation was studied. The accelerated stability studies were also conducted on the co-ground formulation. The results revealed that the dissolution rate of ternary ground mixtures was much higher than that of the intact drug [p < 0.001]. Decreasing the grinding ball size and weight with the same rotation speed resulted in particles with decreased dissolution. On the other hand, increasing the PVP concentration in the formulations reduced the drug dissolution. Dissolution efficiencies [DE[10] and DE[10] for the best dissolved formulation, which consisted of the equal ratio of each co-ground component, were 8.7 and 5 folds higher than the untreated CLA, respectively. This formulation formed nanocrystals with enhanced solubility after dispersing in water. X-ray diffraction, differential scanning calorimetry and infrared spectrophotometry confirmed no chemical interaction and phase transition during the process. Accelerated stability studies confirmed that the co-ground mixture almost remained unchanged in terms of dissolution rate, drug assay and particle size after exposing in stability conditions for three months
ABSTRACT
The aim of this study was to design and optimize a prolonged release matrix formulation of pyridostigmine bromide, an effective drug in myasthenia gravis and poisoning with nerve gas, using hydrophilic - hydrophobic polymers via D-optimal experimental design. HPMC and carnauba wax as retarding agents as well as tricalcium phosphate were used in matrix formulation and considered as independent variables. Tablets were prepared by wet granulation technique and the percentage of drug released at 1 [Y[1]], 4 [Y[2]] and 8 [Y[3]] hours were considered as dependent variables [responses] in this investigation. These experimental responses were best fitted for the cubic, cubic and linear models, respectively. The optimal formulation obtained in this study, consisted of 12.8% HPMC, 24.4% carnauba wax and 26.7% tricalcium phosphate, had a suitable prolonged release behavior followed by Higuchi model in which observed and predicted values were very close. The study revealed that D-optimal design could facilitate the optimization of prolonged release matrix tablet containing pyridostigmine bromide. Accelerated stability studies confirmed that the optimized formulation remains unchanged after exposing in stability conditions for six months
Subject(s)
Cholinesterase Inhibitors/chemistry , Delayed-Action Preparations , Drug Stability , Solubility , Models, Theoretical , Chemistry, Pharmaceutical , TabletsABSTRACT
In the pharmaceutical industry a continuing need for chiral resolution of drugs for various purposes and in diverse matrices exist. For these reasons, analysts may require a number of different separation systems capable of resolving a given pair of enantiomers. Highly sulfated cyclodextrins [HS-CDs] represent a relatively new class of chiral selectors in capillary electrophoresis [CE]. In this investigation the use of HS-CDs as chiral selectors in CE for enantioseparation of tramadol, a highly potent analgesic, as the model drug and the influence of the type of selector and its concentration on enantiomeric resolution were studied. All of the available HSCDs [alpha,beta and gamma] could resolve tramadol enantiomers, but HS-gamma-CD showed better resolution and a baseline resolution was achieved with this selector even at a concentration as low as 0.5% w/v. Additionally, effect of the buffer pH on the enantioresolution was studied. At low pH buffers, in which electroosmotic flow is low in CE, the negatively charged selector prevented the cationic tramadol to migrate out of the capillary even after a long analysis time of 60 minutes. However, at higher pH values [pH=7 or more], the electroosmotic flow is high enough to drag drug-selector complex toward the detector and a reasonable of the enantiomers of the drug was achieved