25 research outputs found
Stability and enzymatic studies with omeprazole: hydroxypropyl-β-cyclodextrin
The original publication is available at www.springerlink.com. A publicação original estĂĄ disponĂvel em www.springerlink.comOmeprazole (OME) exhibits low stability to light, heat and humidity. In stress conditions OME stability should improve under inclusion complex form with hydroxypropyl-b-cyclodextrin (HPbCD). Stability of OME, its physical mixture (PM) with HPbCD and OME:HPbCD inclusion complex was assessed during 60 days. The inclusion complexes were prepared by kneading and freezedrying techniques and characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). A molecular modelling was also held to predict the most probable tridimensional conformation of inclusion complex OME:HPbCD. The inhibitory activity of free and complexed OME on selected enzymes, namely, papain (protease model of the proton pump) and acetylcholinesterase (enzyme present in cholinergic neurons and also involved in Alzheimerâs disease) was compared. The results obtained show that HPbCD do not protect against OME degradation, in any prepared powder, in the presence of light, heat and humidity. This may indicate that the reactive group of OME is not included in the HPbCD cavity.
This fact is supported by molecular modelling data, which demonstrated that 2-pyridylmethyl group of OME is not included into the cyclodextrin cavity. In relation to enzymatic assays it was observed that free OME and OME in the binary systems showed identical inhibitory activity on papain and acethylcolinesterase, concluding that HPbCD do not affect OME activity on these two enzymes
Formulation and evaluation of carvedilol microcapsules using Eudragit NE30D and sodium alginate
Layered double hydroxides: A review
267-272Combination of two-dimensional layered materials and intercalation technique offers a new area for developing nanohybrids
with desired functionality. Layered double hydroxides (LDHs) are mineral and synthetic materials with positively charged
brucite type layers of mixed metal hydroxides. Exchangeable anions located in interlayer spaces compensate for positive
charge of brucite type layer. Since most biomolecules are negatively charged, can be incorporated between LDHs. A number of
cardiovascular, anti-inflammatory agents are either carboxylic acids or carboxylic derivatives and could be ion exchanged
with LDHs to have controlled release. LDHs have technological importance in catalysis, separation technology, medicalscience and nanocomposite material engineering
Multiwall Carbon Nanotube-Induced DNA Damage and Cytotoxicity in Male Human Peripheral Blood Lymphocytes
Trends in floating drug delivery systems
11-21Among novel drug delivery systems, rate controlled oral drug delivery system forms an important area. Research is directed towards overcoming physiological problems, such as short gastric residence times (GRT) and unpredictable gastric emptying times. Prolonged GRT may widen the stomach potential as a drug-absorbing organ. Several approaches are currently utilized in the prolongation of the GRT, including floating drug delivery systems (FDDS), swelling and expanding systems, polymeric bioadhesive systems, modified-shape systems, high-density systems and other delayed gastric emptying devices. Narrow absorption window drugs compounded in such systems have improved in vivo absorption properties. These findings are an important step towards the implementation of FDDS in the clinical setting. In this review, the current technological developments of FDDS including patented delivery systems and marketed products have been discussed. In addition, the pharmaceutical basis of their design, their advantages and future potential for oral controlled drug delivery are discussed
Design and development of co-processed excipients for fast dissolving tablets of Irbesartan by melt agglomeration technique
Design and Evaluation of a Sustained Release Gastroretentive Dosage Form of Captopril: A Technical Note
Preformulation Study of the Inclusion Complex Irbesartan-β-Cyclodextrin
The aim of the present work was to improve the solubility and dissolution profile of Irbesartan (IRB), a poorly water-soluble drug by formation of inclusion complex with β-cyclodextrin (βCD). Phase solubility studies revealed increase in solubility of the drug upon cyclodextrin addition, showing ALâtype of graph with slope less than one indicating formation of 1:1 stoichiometry inclusion complex. The stability constant (Ks) was found to be 104.39 Mâ1. IRBâβCD binary systems were prepared by cogrinding, kneading using alcohol, kneading using aqueous alcohol, and coevaporation methods. Characterization of the binary systems were carried out by differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, and proton nuclear magnetic resonance. The dissolution profiles of inclusion complexes were determined and compared with those of IRB alone and physical mixture. Among the various methods, coevaporation was the best in which the solubility was increased and dissolution rate of the drug was the highest. The study indicated the usefulness of cyclodextrin technology to overcome the solubility problem of IRB