File Name: complexation and protein binding physical pharmacy .zip
Complex compounds: Those molecules in which most bonding structures can be described by classical valence theories between atoms, but one or more of these bonds are somewhat anomalous. Complexation: It is the association between two or more molecules to form a non bonded entity with a welldefined stoichiometry. Ligands: The ligand is a molecule that interacts with another molecule the substrate by co-ordinate bonds and form a complex.
Chelatation: It is the process of formation of two or more separate coordinate bonds between a polydentate ligand and a single central atom. Inclusion complexes: These are the compounds in which one of the components is trapped in the open lattice or cage like crystal structure of the other. Clatharates: It is a cage like complex in which the coordinating compound is entrapped. Protein Binding: This is the phenomenon of complex formation of drugs with proteins.
Complexation is the association between two or more molecules to form a non bonded entity with a well-defined stoichiometry. In broad terms, complexation is used to characterize covalent or non-covalent interactions between two or more compounds that are capable of independent existence.
The intermolecular forces involved in complex formation are the covalent bond, the vanderwall forces, the dipole-dipole interaction, and the hydrogen bond etc. Complexes are formed because of the donor acceptor mechanism.
Donor is the neutral molecule or ion of non metallic substance that can donate the lone pair of electrons. Acceptor is the metallic ion or sometimes it might a neutral atom. Different steps involved are. The filled ligand orbital overlaps the empty metal ion orbital. The metal ion accepts it 4. Form one of the covalent bonds of the complex ion. Such a bond, in which one atom in the bond contributes both electrons, is called a coordinate covalent bond.
Metal complexex or Coordination complexes a. Inorganic type b. Chelates c. Olefin type d. Aromatic type 2. Organic molecular complexes a. Quinhydrone type b. Caffeien complex c. Picric acid type d.
Polymeric complex 3. Inclusion or occlusion Complexex a. Clathrate complex b. Channel lattice c. Layer type d. Ligands are ions or molecules that contain one or more pairs of electrons that can be shared with the metal.
Metal complexes can be neutral, positively charged, or negatively charged. Electrically charged metal complexes are sometimes called complex ions. A coordination compound contains one or more metal complexes. Ammonia, which has single pair of electrons basic group for bonding with metal ion, is called unidentate ligand.
Example: Oxalate anion, ethylenediamine etc. The chloride ion in the coordinate sphere can't precipitated by silver nitrate. Cl and NH3 in coordinate sphere are called ligands. Metal and ligands bonded to each other by electrostatic or covalent bond. It is usually an even number.
For Co, coordination number is 6. The coordination number of Cobalt is 6. Ground-state electronic configuration for the trivalent cobalt ion, Co III is 3d. In complexation, electrons from half filled orbitals shift to other orbital and create vacant orbitals. Then ligands donate electron pairs to vacant orbitals of metal ion and form complexes. For example Ethylene diarnine tetraacetic acid EDTA has two donor nitrogen and acts as a bidentate two-toothed Ligand.
When a drug forms a metal chelate, the solubility and absorption of both drug and metal ion may be affected, and drug chelation can lead to either increased or decreased absorption. Example citric acid,tartrates and EDTA. Application of chelating agents 1. EDTA is used to remove calcium ion from hard water 2.
Oxidative degradation of drug preparations and ascorbic acid in fruit juice can be prevented by chelation with EDTA 3. EDTA is also used as In vitro anticoagulant. EDTA is used to detoxify poisonous metal agents, such as mercury, arsenic, and lead 5. EDTA is used to remove colour impurities from antibiotic preparations 7. These complexes are water soluble. These types of complexes are generally used as catalysts in the manufacture of bulk drugs and also in the analysis of drugs.
If complex is formed by pie bond between metal ion and aromatic molecule, then it is called 1 - bond complex. If complex is formed by sigma bond between metal ion and aromatic molecule, then it is called sigma- bond complex. Classification of organic molecular complex 7. Complex is formed by overlapping of 1t cloud of electron deficient benzoquinone with electron rich hydroquinone.
These are used as an electrode to determine pH. Drugs such as benzocaine, procaine and tetracaine form complexes with caffeine. The mechanism behind this is a hydrogen bonding between polarized carbonyl group of caffiene and hydrogen atom of acidic drug. Caffeine drug complexes a. Also these complexes are used to mask bitter tasteof drug. The complex is indication of magnitude of carcinogenic activity.
These type of interaction produces Incompatibilities in suspensions, emulsions, suppositories and ointments. Also it may lead to precipitation, flocculation, delayed biologic absorption, loss of preservative action and other undesirable physical, chemical and pharmacological effects.
Example: 1. Dissolution rate of ajmaline is enhanced by complexation with PVP due to the aromatic ring of ajmaline and the amide groups of PVP to yield a dipole dipole induced complex 2. Polyolefin container interact with drugs which can result in loss of the active component in liquid dosage forms.
Choleic acids form. Deoxycholeic acid molecules can form channels in which molecules will get inside. Compounds such as clay montmorillonite, the main constituent of bentonite, can trap hydrocarbons, alcohols and glycols between the layers of their lattices. As a a result alternate monomolecular layers of guest and host are formed.
However, these may be useful for catalysis due to a larger surface area. It is available as white crystalline powder. For example: Cage like structure formed through hydrogen bonding of hydroquinone molecules. Small molecules in cage get entrapped and form clatharates. Hydrogen bonding hydrogen atoms not shown. They are the inclusion compounds. Monomolecular inclusion compounds involve the entrapment of a single guest molecule in the cavity of one host molecule.
Most of the host molecules are cyclodextrins. The entrance of the cavity is hydrophilic in nature and the interior of the cavity is relatively hydrophobic. Hydrophilic exterior Hydrophobic interior Cavity for encapsulating hydrophobic drugs Entrapped aspirin molecule. In various types of poisonings: chelating agents are used as antidote in hevy metal poisoning.
For example Dimercaprol in case of mercury and arsenic poisoning. However, in the presence of EDTA or surfactant such as SLS or dioctyl sodium sulfosuccinate, intestinal absorption of heparin is increased. Complexation is used in solubilisation: Adrenochrome monosemicarbazone. Another example is The complexation of caffeine by sodium benzoate increases solubility of caffeine 5.
Stability of product: Example Hydrolysis of Local anesthetic esters can be decreased by complexation with caffeine. And less irritation at the site of injection. In diagnosis: Complex of Technetium 90 a radionuclide with citrate. Partition coefficient: The study of complexes is essential to assess drug action because complexes. Several methods of estimation of complexes have been developed as follows: 1. Method of continuous variation 2. The value is given as the mean of the values of the individual species in the mixture.
We think you have liked this presentation. If you wish to download it, please recommend it to your friends in any social system. Share buttons are a little bit lower. Thank you! Published by Jordan Terry Modified over 2 years ago. In the context of this course, it will be used to characterize the covalent or noncovalent interactions between two or more compounds that are capable of independent existence. Complexes have been usually referred to as coordination compounds.
Solubility of Drugs Solubility expressions, mechanisms of solute-solvent interactions, ideal solubility parameters, solvation and association, quantitative approach to the factors influencing solubility of drugs, diffusion principles in biological systems. Partially miscible liquids, critical solution temperature and applications. Distribution law, its limitations and applications. States of Matter and Properties of Matter States of matter, changes in the states of matter, latent heats, vapour pressure, sublimation critical point, eutectic mixtures, gases, aerosols — inhalers, relative humidity, liquid complexes, liquid crystals, glassy states, solid-crystalline, amorphous and polymorphism. Physicochemical Properties of Drug Molecules Refractive index, optical rotation, dielectric constant, dipole moment, dissociation constant, determinations and applications. Surface and Interfacial Phenomenon Liquid interface, surface and interfacial tensions, surface free energy, measurement of surface and interfacial tensions, spreading coefficient, adsorption at liquid interfaces, surface active agents, HLB scale, solubilisation, detergency and adsorption at solid interface. Complexation and Protein Binding Introduction, classification of complexation, applications, methods of analysis, protein binding, complexation and drug action, crystalline structures of complexes and thermodynamic treatment of stability constants.
AND PROTEIN BINDING. INTRODUCTION Obses. Complexation is a process where complexes or coordination (i) Physical state Chelates in Pharmacy.
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The acceptor, or constituent that accepts a share in the pair of electrons, is frequently a metallic ion, although it can be a neutral species. Any nonmetallic atom or ion, whether free or contained in a neutral molecule or in an ionic compound, that can donate an electron pair may serve as the donor. For examples: 1 chelates of tetracycline with calcium are less water soluble and are poorly absorbed. Milk; antacid, iron-supplement.. Complex: Different than staring materials!! Thus calorimetric methods to assay procainamide in injectable solutions is based on the formation of a complex of procainamide with cupric ion at pH 4 to 4. Metal Ion Complexes: a.
Complex compounds: Those molecules in which most bonding structures can be described by classical valence theories between atoms, but one or more of these bonds are somewhat anomalous. Complexation: It is the association between two or more molecules to form a non bonded entity with a welldefined stoichiometry. Ligands: The ligand is a molecule that interacts with another molecule the substrate by co-ordinate bonds and form a complex. Chelatation: It is the process of formation of two or more separate coordinate bonds between a polydentate ligand and a single central atom. Inclusion complexes: These are the compounds in which one of the components is trapped in the open lattice or cage like crystal structure of the other.
PHYSICAL PHARMACEUTICS-I (Theory). UNIT-IV - COMPLEXATION AND PROTEIN BINDING: INTRODUCTION: ➢ Complexation is the process of complex.
In the second edition of Pharmaceutical Dosage Forms and Drug Delivery the authors integrate aspects of physical pharmacy, biopharmaceuticals, drug delivery, and biotechnology, emphasizing the increased attention that the recent spectacular advances in dosage form design and drug delivery, gene therapy, and nanotechnology have brought to the field. Narang brings an industrial practitioner perspective with increased focus on pharmacy math and statistics, and powders and granules Reorganized into three parts: Introduction, Physicochemical Principles, and Dosage Forms Chapters on pharmaceutical calculations, compounding principles, and powders and granules provide a complete spectrum of application of pharmaceutical principles Expansion of review questions and answers clarifies concepts for students and adds to their grasp of key concepts covered in the chapter Coverage of complexation and protein binding aspects of physical pharmacy includes the basic concepts as well as recent progress in the field Although there are numerous books on the science of pharmaceutics and dosage form design, most cover different areas of the discipline and do not provide an integrated approach to the topics. This book not only provides a singular perspective of the overall field, but it supplies a unified source of information for students, instructors, and professionals.
Plasma protein binding refers to the degree to which medications attach to proteins within the blood. A drug's efficiency may be affected by the degree to which it binds. The less bound a drug is, the more efficiently it can traverse cell membranes or diffuse. A drug in blood exists in two forms: bound and unbound. Depending on a specific drug's affinity for plasma protein, a proportion of the drug may become bound to plasma proteins, with the remainder being unbound.
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