O slideshow foi denunciado.
Utilizamos seu perfil e dados de atividades no LinkedIn para personalizar e exibir anúncios mais relevantes. Altere suas preferências de anúncios quando desejar.

crude drugs evaluation

1.112 visualizações

Publicada em

crude drugs evaluation

Publicada em: Saúde e medicina
  • Seja o primeiro a comentar

crude drugs evaluation

  1. 1. Pharmacopoeial standards applicable to crude drugs • Pharmacopoeial standards are set to evaluate crude drugs in raw or powdered form. The evaluation means determination of quality and purity. • Evaluation is done by comparing unknown samples with known monographs written in Pharmacopoeia. • It includes:
  2. 2. 1. Organoleptic Evaluation The organoleptic evaluation means the study of crude drugs with sense organs which includes its external morphology, colour, taste, odour, etc. Basically there are two organoleptic characters: Morphological characters It includes organised and unorganised portion of the plant. Organised parts includes stem, roots, fruits, flowers, seeds, leaves, herbs, etc. Unorganised parts includes resin, gums, latex, etc. Sensory characters Colour, odour and taste are sensory characters of the drugs. e.g: clove and cinnamom gives characteristic odour ginger and capsicum gives pungent taste glycyrrhiza and honey are sweet
  3. 3. 2. Microscopical Evaluation • The crude drugs are evaluated microscopically by their known histological characters. The shape, size, relative position of cells and tissues, chemical nature of cell wall and cell content are determined. Basically following constants are used in microscopical measurements: a) Stomatal Number The average number of stomata per square mm of the epidermis is known as stomatal number.
  4. 4. b) Stomatal Index The percentage proportion of the number of stomata to the number of epidermal cells of a leaf is known as stomatal index. Stomatal Index = S × 100 E+S S= No. of stomata per unit area E= No. of epidermal cells in the same area c) Vein-islet number is defined as the number of vein islets per sq. mm of the leaf surface between midrib and the margin. d) Vein termination number is defined as the number of veinlet terminations per sq. mm of the leaf surface between midrib and margin. e) Palisade ratio is defined as the average number of palisade cells beneath each epidermal cell.
  5. 5. Atropa belladona Leaf Constants Stomatal Number 77-115 (Lower Epidermis) Stomatal Index 20.2-23 (Lower Epidermis) Vein Termination Number 6.3-10.3 Palisade ratio 6-10
  6. 6. Digitalis Purpurea Leaf Constants Vein Islet Number 2-5.5 Palisade ratio 3.7-4.2
  7. 7. 3. Physical Evaluation The physical parameters are determined for the evaluation of crude drugs. It includes: a) Moisture content The moisture content will be determined by heating a drug at 105°C in an oven to a constant weight. [Note: The excessive moisture content will deteriorate the quality of drug by activating enzymes and growth of micro-organisms.] e.g: starch should contain NMT 15% moisture
  8. 8. b) Ash Content The residue remaining after the incineration of drug is the ash content of the drug. Total ash value is determined at around 450°C which may contain carbonates, phosphates, oxides, silicates and silica. Sulphated ash is determined by treating drug with dilute sulphuric acid at around 600°C. Acid insoluble ash is determined by treating total ash with dilute hydrochloric acid. e.g: Drug Total Ash % w/w (NMT) Acid insoluble ash % (NMT) Clove 7 0.75 Cannabis 15 5
  9. 9. c) Rf Value Rf means the flow ratio and it is defined as the ratio of distance covered by the solute to the distance covered by the solvent in chromatography.
  10. 10. d) Refractive index Refractive index is the ratio of velocity of light in vacuum to velocity of light in the substance. Refractive Index = Velocity of light in vacuum Velocity of light in substance The value of R.I. is constant and very useful for the standardization of Volatile and fixed oils. It is measured by refractometer. e.g: clove oil has refractive index 1.530-1.531
  11. 11. e) Optical rotation It is the degree of rotation of plane polarized light when it passes through an optically active substance. If the rotation of plane polarized light is towards right-Dextrorotatory (+). If the rotation of plane polarized light is towards left-Levorotatory (-). Optical rotation is determined with the help of Polarimeter. e.g: clove oil has optical rotation 0° to -1.5° Dextrose (+52.7°) - Dextrorotatory Levulose (Fructose) (-92°) - Levorotatory
  12. 12. f) Foreign organic matter The parts other than the drug are known as foreign organic matters. Its maximum limit is given in the monographs of particular drug. g) Extractive Value Extract is obtained from crude drugs by maceration or continuous extraction by soxhlet extractor. The solvent used for the extraction dissolves the phytochemicals present in crude drugs like alkaloids, glycosides, tannins, resins, etc. Solvents like alchohol, water, ether, etc are used for extraction.
  13. 13. h) Volatile oil content Volatile oil is obtained from crude drugs using clevenger apparatus in the laboratory. Ether is used as solvent for obtaining volatile oils. i) Melting Point It is the temperature required to melt down the drug. Melting points are sharp and constant in pure chemicals and phytochemicals. j) Viscosity It is the property of a liquid to resist its flow. It is measured by using Ostwald viscometer.
  14. 14. 4. Chemical Evaluation Chemical evaluation of crude drugs involves isolation, purification, identification, chemical tests and chemical assays. Phytochemical screening is the qualitative chemical evaluation. It includes test for phytochemicals like carbohydrate, protein, alkaloids, glycosides, tannins, etc. Quantitative chemical tests includes acid value, saponification value, ester value, etc e.g: Tannic acid test for alkaloids Borntrager’s test for glycosides
  15. 15. 5. Biological Evaluation Biological evaluation is done to determine effect & potency of drug in living organisms, animal preparations or isolated living tissue. It is also known as bioassay. It can evaluate both pharmacological activity and toxicological activity of a drug. Biological evaluation is done to confirm the test after physical and chemical test. Biological evaluation can be: i) Pre-clinical testing: Testing in laboratory animals like mouse, rat, pig, dog, etc. ii) Clinical testing: Testing in human volunteers.

×