177 research outputs found
Advanced Technologies for Oral Controlled Release: Cyclodextrins for oral controlled release
Cyclodextrins (CDs) are used in oral pharmaceutical formulations, by means of inclusion complexes formation, with the following advantages for the drugs: (1) solubility, dissolution rate, stability and bioavailability enhancement; (2) to modify the drug release site and/or time profile; and (3) to reduce or prevent gastrointestinal side effects and unpleasant smell or taste, to prevent drug-drug or drug-additive interactions, or even to convert oil and liquid drugs into microcrystalline or amorphous powders. A more recent trend focuses on the use of CDs as nanocarriers, a strategy that aims to design versatile delivery systems that can encapsulate drugs with better physicochemical properties for oral delivery. Thus, the aim of this work was to review the applications of the CDs and their hydrophilic derivatives on the solubility enhancement of poorly water soluble drugs in order to increase their dissolution rate and get immediate release, as well as their ability to control (to prolong or to delay) the release of drugs from solid dosage forms, either as complexes with the hydrophilic (e.g. as osmotic pumps) and/ or hydrophobic CDs. New controlled delivery systems based on nanotechonology carriers (nanoparticles and conjugates) have also been reviewed
Cyclodextrins and ternary complexes: technology to improve solubility of poorly soluble drugs
Cyclodextrins (CDs) are cyclic oligosaccharides composed of D-glucopyranoside units linked by glycosidic bonds. Their main property is the ability to modify the physicochemical and biological characteristics of low-soluble drugs through the formation of drug:CD inclusion complexes. Inclusion complexation requires that host molecules fit completely or partially within the CD cavity. This adjustment is directly related to the physicochemical properties of the guest and host molecules, easy accommodation of guest molecules within the CD cavity, stoichiometry, therapeutic dose, and toxicity. However, dosage forms may achieve a high volume, depending on the amount of CD required. Thus, it is necessary to increase solubilization efficiency in order to use smaller amounts of CD. This can be achieved by adding small amounts of water-soluble polymers to the system. This review addresses aspects related to drug complexation with CDs using water-soluble polymers to optimize the amount of CD used in the formulation in order to increase drug solubility and reduce dosage form volume.Ciclodextrinas (CDs) sĂŁo oligossacarĂdeos cĂclicos, compostos por unidades D-glicopiranosĂdicas ligadas entre si por meio de ligaçþes glicosĂdicas e sua principal propriedade estĂĄ na capacidade de alterar as caracterĂsticas fĂsico-quĂmicas e biolĂłgicas de fĂĄrmacos com baixa solubilidade por meio da formação de complexos de inclusĂŁo fĂĄrmaco:CD. Para a formação dos complexos de inclusĂŁo a molĂŠcula hospedeira necessita ajustar-se total ou parcialmente no interior da cavidade da CD, onde este ajuste estĂĄ diretamente ligado a propriedades fĂsico-quĂmicas da molĂŠcula hĂłspede e hospedeira, facilidade de alojamento da molĂŠcula hĂłspede no interior da cavidade da CD, estequiometria, dose terapĂŞutica e toxicidade. No entanto, as formas farmacĂŞuticas podem atingir um elevado volume, em função da quantidade de CD requerida, sendo necessĂĄrio aumentar sua eficiĂŞncia de solubilização para que seja possĂvel utilizar menores quantidades das mesmas. Isso pode ser obtido com a inclusĂŁo de pequenas quantidades de polĂmeros hidrossolĂşveis ao sistema. Nessa revisĂŁo, sĂŁo abordados aspectos relacionados Ă complexação de fĂĄrmacos com ciclodextrinas empregando-se polĂmeros hidrossolĂşveis para otimização da quantidade de CD utilizada na formulação, com a finalidade de aumentar a solubilidade do fĂĄrmaco e reduzir o volume das preparaçþes
Polymorphism: an evaluation of the potential risk to the quality of drug products from the FarmĂĄcia Popular Rede PrĂłpria
Polymorphism in solids is a common phenomenon in drugs, which can lead to compromised quality due to changes in their physicochemical properties, particularly solubility, and, therefore, reduce bioavailability. Herein, a bibliographic survey was performed based on key issues and studies related to polymorphism in active pharmaceutical ingredient (APIs) present in medications from the Farmácia Popular Rede Própria. Polymorphism must be controlled to prevent possible ineffective therapy and/or improper dosage. Few mandatory tests for the identification and control of polymorphism in medications are currently available, which can result in serious public health concerns
Oral bioavailability and hypoglycaemic activity of tolbutamide/cyclodextrin inclusion complexes
The purpose of the present study was to evaluate the enhancement of tolbutamide (TBM) oral bioavailability and hypoglycaemic activity through complexation with [beta]-cyclodextrin ([beta]-CD) and hydroxypropyl-[beta]-cyclodextrin (HP-[beta]-CD). TBM and its freeze-dried inclusion complexes were administered to rabbits (New zealand breed; n=6), in a dose of 20 mg/kg. TMB plasma levels were measured by HPLC and glucose levels were analysed according to Trinder (Trinder, P., 1969. Determination of glucose in blood using glucose oxidase with an alternative oxygen acceptor. Ann. Clin. Biochem. 6, 24-28). The pure drug attained a maximum of plasma concentration (Cmax) of 18.58Âą3.27 [mu]g/ml at 8.5 h (Tmax), whereas with inclusion complexes, Cmax increased about two times and appeared at ca. 4 h. AUC0-24 of complexes was about 1.6 times as much as that of the pure drug. Thus, the extent of oral absorption of TBM from inclusion complexes was significantly greater and faster when compared with drug alone. In addition, without cyclodextrins the maximum hypoglycaemic effect (CVGmax) of TBM (34.1%) was observed at 5.6 h (Tgmax). CVGmax of TBM/[beta]-CD and TBM/HP-[beta]-CD inclusion complexes were 34.1% (at 6.5 h) and 37.7% (at 5.1 h), respectively. AAC0-24 of inclusion complexes was 1.4 times larger than that of pure drug. Hence, the oral administration of complexed TBM not only improved the drug absorption, but also the TBM hypoglycaemic activity.http://www.sciencedirect.com/science/article/B6T7W-40T9G9V-P/1/3f0ee31e925f45ea5e88caafa81737f
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