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VOLUME OF DISTRIBUTION

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The volume of distribution (VD) , also known as apparent volume of distribution, is used to quantify the distribution of a medication between plasma and the rest of the body after oral or parenteral dosing.   It is defined as the volume in which the amount of drug would need to be uniformly distributed to produce the observed blood concentration.   Volume of distribution may be increased by renal failure (due to fluid retention) and liver failure (due to altered body fluid and plasma protein binding). Conversely it may be decreased in dehydration.  EQUATION:  The volume of distribution is given by the following equation:    Therefore the dose required to give a certain plasma concentration can be determined if the VD for that drug is known. The VD is not a physiologic value; it is more a reflection of how a drug will distribute throughout the body depending on several physicochemical properties, e.g. solubility, charge, size, etc. ...
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BASIC CONCEPTS AND IMPORTANCE OF VARIOUS PHARMACOKINETIC PARAMETERS

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INTRODUCTION:  Pharmacokinetics, sometimes abbreviated as PK, (from Ancient Greek pharmakon "drug" and kinetikos "to do with motion") is dedicated to the determination of the fate of substances administered externally to a living organism. Pharmacokinetics is the science of the kinetics of drug absorption, distribution, and elimination (ie, excretion and metabolism). The description of drug distribution and elimination is often termed drug disposition.  Pharmacokinetics is often studied in conjunction with pharmacodynamics.  Pharmacodynamics explores what a drug does to the body, whereas pharmacokinetics explores what the body does to the drug. Pharmacokinetics includes the study of the mechanisms of absorption and distribution of an administered drug, the rate at which a drug action begins and the duration of the effect, the chemical changes of the substance in the body (e.g. by enzymes) and the effects and routes of excretion of the metabolites of the dru...
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PLANT LAYOUT FOR CAPSULE MANUFACTURING DEPARTMENT & MANUFACTURING PROCESS

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PLANT LAYOUT  FOR CAPSULE MANUFACTURING DEPARTMENT: ENVIRONMENT CONDITION FOR CAPSULE FILLING AREA Humidity:          Not more than 35% RH Temperature:    Not more than 25% Area of each room, position of equipments, washing, drying, and sanitary facilities must be in accordance with GMP. MANUFACTURING PROCESS: CHEMCAPS Limited is an India based young and dynamic organization engaged in the manufacture and export of 'empty hard gelatin capsules' under the brand name of 'Chemlock' for discerning customers around the globe. COMPOSITION                                     Gelatin                                     Water                       ...
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Practical: Determination of Angle of repose, Carre's Index & Hausner ratio of given powder

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Aim:  Determination of Angle of repose, Carre's Index & Hausner ratio of given powder Reference: L. Lachman CVS Subramanyam Requirements: Apparatus:  Funnel, beaker, measuring cylinder, funnel holding stand Chemicals:  Lactose, Na. carbonate, Boric acid Theory topics: Angle of Repose: Introduction, Definition, Equation, Description, various methods of determination, factors affect, Pharmacopoeia specification, effect on flow property Fig: Methods of angle of repose Carr’s consolidation Index (CI) Introduction, Definition, Equation, Description, various methods of determination, factors affect, Pharmacopoeia specification, effect on flow property Hausner’s Ratio: Introduction, Definition, Equation, Description, various methods of determination, factors affect, Pharmacopoeia specification, effect on flow property Procedure: Angle of repose: Weighed amt. of powder was taken (lactose-5gm, na. bicarbonate-10gm, Boric acid-10gm) Weighed p...
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PLASMA PROTEIN BINDING

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Introduction: It is binding of drug to plasma protein in blood component.  Binding of drugs to plasma proteins is reversible.  Various plasma protein to which drug binds includes Albumin, α1-Acid glycoprotein (orosomucoid), lipoprotein, globulins, etc.  Order of binding of drugs to various plasma proteins:  Albumin > α1-Acid glycoprotein (orosomucoid) > Lipoproteins > Globulins Such bound drug is both pharmacokinetically as well as pharmacodynamically inert i.e. a protein bound drug is neither metabolized nor excreted nor it  is pharmacologically active.  A bound drug is also restricted since it remains confined to a particular tissue for which it has greater affinity. Moreover, such bound drug because of its enormous size cannot undergo membrane transport & thus its half life is increased.  However this binding is rapidly reversible and non-specific – that is many drugs may bind to the same protein. Drug–plasma protein bindi...
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