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) são oligossacarídeos cíclicos, compostos por unidades D-glicopiranosídicas ligadas entre si por meio de ligações glicosídicas e sua principal propriedade está na capacidade de alterar as características físico-químicas e biológicas de fármacos com baixa solubilidade por meio da formação de complexos de inclusão fármaco:CD. Para a formação dos complexos de inclusão a molécula hospedeira necessita ajustar-se total ou parcialmente no interior da cavidade da CD, onde este ajuste está diretamente ligado a propriedades físico-químicas da molécula hóspede e hospedeira, facilidade de alojamento da molécula hóspede no interior da cavidade da CD, estequiometria, dose terapêutica e toxicidade. No entanto, as formas farmacêuticas podem atingir um elevado volume, em função da quantidade de CD requerida, sendo necessário aumentar sua eficiência de solubilização para que seja possível utilizar menores quantidades das mesmas. Isso pode ser obtido com a inclusão de pequenas quantidades de polímeros hidrossolúveis ao sistema. Nessa revisão, são abordados aspectos relacionados à complexação de fármacos com ciclodextrinas empregando-se polímeros hidrossolúveis para otimização da quantidade de CD utilizada na formulação, com a finalidade de aumentar a solubilidade do fármaco e reduzir o volume das preparações

Hydrodynamic properties of cyclodextrin molecules in dilute solutions

Three well-known representatives of the cyclodextrin family were completely characterized by molecular hydrodynamics methods in three different solvents. For the first time the possibility of an estimation of velocity sedimentation coefficients s between 0.15 and 0.5 S by the numerical solution of the Lamm equation is shown. Comparison of the experimental hydrodynamic characteristics of the cyclodextrins with theoretical calculations for toroidal molecules allows an estimation of the thickness of the solvent layers on the surface of cyclodextrin molecules

Polymorphism: an evaluation of the potential risk to the quality of drug products from the Farmácia Popular Rede Própria

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