Quality control of crude drugs by different methods

Quality control of crude drugs

1. Topic -03 Quality Control of Crude Drugs  

2. Adulteration and methods of adulterating the crude drugs – Definition – adulteration is the debasement of an article. Reasons for adulteration of crude drugs – Where from drug is obtained from India or from other countries. Less availability of the drug in market. High price of the drug in market. To gain high profit. When drug are sold illegally. Adulteration may be deliberate or accidental Adulteration involves conditions such inferiority spoilage and substitution. Different means / methods of adulterating drugs --- Various methods of adulteration of crude drugs are as follows: 1.Replacement of exhausted drugs – This is observed in case of costly drugs such as cloves, saffron , tea, fennel, ginger etc. this drugs are exhausted for their active constituents and again used with genuine. 2.Substitution with superficially similar but inferior drugs - In the inferior quality drugs are substituted for official drugs For Ex. Cloves are adulterated by mother cloves. Saffron is adulterated with saf flower .

3. 3.Substitution by artificial manufactured drugs – In case of costly drugs this is observed. For.Ex – paraffin wax is tinged yellow and supplied as yellow bees wax while artificial invert sugar is mixed with natural honey. 4.Substitution by standard commercial verities – Instead of official drugs varieties are supplied. For Ex. – red chilies are substituted by verity capsicum annum. Senna leaves are substituted by Arabian senna . Nuxvomica substituted by strychonousnux-blenda etc 5.Presence organic matter from same plant – In this case of advantage of similar colour , odour and constituents is taken into consideration and other parts of same plants are added to genuine drugs. Ex. cloves are mixed with cloves stalks caraway and ajowan fruits are mixed with other parts of inflorescence. 6.Addition of synthetic material -- many times synthetic chemicals which constituents same chemical genuine drugs. For. Ex. – benzyl benzoate to balsam of lemon grass, camphor oil or eucalyptus oil in oil of rosemary is added

4. Drug evaluation and significance of pharmacopeial standards – Evaluation of crude drugs means confirmation of its identity and determination of its quality purity. After adulteration of crude drugs we have to detect the nature of adulteration in the crude drugs several methods are employed for detection of adulteration in genuine drugs which are as follows: Organoleptic (morphological) evaluation Microscopic evaluation Physical evaluation Chemical evaluation Biological evaluation

5. 1.Organoleptic / morphological / macroscopical / sensory evaluation – This evaluation of crude drug is applicable for both organised and unorganised type of crude drugs. This evaluation is done by observing following characters of crude drugs – colour , odour , taste, size, shape, texture, touch and special features of there. For Ex.- Aromatic odour of umbelliferous fruits sweet taste of liquorice crimson red colour . 2.Microscopical evaluation / histological evaluation --- This evaluation is useful for organized types of crude drugs. In this more detail examination of a crude drug is performed. With the help of microscope we will study of following particulars for organized crude drug- Type of cells, cell content, presence or absence of starch, calcium oxalate, fibers, stomata, trychomes etc. Structures and their detail are studied For Ex. – Presence of lignified trychomes in nuxvomica seed is special identifying characters. Following are few constant gives importance of microscopic measurements

6. a) Stomatal number -- It is the average number of stomata present per square mm. of the epidermis. Stomatal number is constant for particular species of same age. Hence it is considered as diagnostic characters for identification of a leaf drug. Adulterationcan also be detected by Stomatal number 087 in upper epidermis. Daturamoxia have Stomatal number 141 in upper epidermis. b) Stomatal index – It is the percentage which the number of stomata form to form the total number of epidermal cells. Each stomata being counted as one cell. (S×100)/((E+S))

7. Where, S.I - Stomatal Index. S - Number of stomata per unit area. E - Epidermal cell in same area Where ever stomatal number various with age of leaf and by climatic condition stomatal index is relatively constant. Therefore is a diagnostic character for identification of leaf in adulteration. For Ex. – Indian senna – S.I is 17 – 20 Alexandrian senna – S.I is 10.8 – 12.6 c)Vein islet number – It is the number of vein islet per sq. mm of leaf surface. It is constant for a given species of a plant it usually do not change with age of leaf For Ex. Digitalis purpurea vein islet no is no is 0.2 to 16.

8. d)Palisade ratio – It is the average number of palisade cells beneath one epidermal cell using four continuous epidermal cells for count. This descent changes and is therefore considered as identification parameter for leaf structure. For Ex. Atropa belladonna palisade ratio is 6 to 10. Daturastramonium ratio is 4 to 7. Digitalis purpurea palisade ratio is 3.7 to 4.2. e) Quantitative microscopy ( lycopodium spore method) – It is important analytical technique for powered drugs specially when chemicals and other falls. Lycopodium spores are very characteristics in shape and appearance uniform in size (25µm) another average 94000 spores per mg are present in powdered crude drugs are evaluated by this technique. If it contains,

9. Well defined particles which may be counted. E.g. starch grains or pollen grains. Single layered cell or tissues. Objects of uniform thickness. This method can be used for evaluation of powdered clove, ginger, cardamom, nutmeg and umbelliferous fruits. 3. Physical evaluation – There are certain physical standard are determined for drug which are constants in the pure form of a drugs. Therefore they are considered as the criteria to judge the purity of a drug some are as follows.

10. A) Moisture contain – Moisture content of a drug should be determined and also controlled to make the solution of definite strength. Moisture content of a dug should be chemical change or either due to microbial combination. Moisture content is determined by heating a drug at 105° C in an oven to a constant weight for volatile drug toluene distillation method is used. Ex. Aloe contains < 10 % w/w moisture contain. Digitalis contain< 5 % w/w moisture content. Acacia contains < 15 % w/w moisture content. B)Viscosity – viscosity of a liquid is constant at a given temperature hence it can be used as a means of standardization of liquid drugs. Ex. Liquid paraffin has viscosity > 64 centistokes. C)Melting point – it is the one of the parameter to judge the purity of drug. In the purity of are very sharp and constant. Ex. Cocoa butter have melting point 30° to 33° C. Bees wax have melting point 62°to 65° C. Wool fat have melting point 34°to 40° C

11. D)Optical relation – some substance have found to have the property of rotating the plane of polarized light in pure state are known as optically active. This property is known as optical rotation. Plane of polarized light may rotated towards right. (+ Dextrorotatory) or left (- laevorotatory) optical rotation is determined at 25°C using sodium lamp as source of light. e.g.optical rotation of honey is +3° to -15° E)Refractive index – when ray of light passes from one medium to another of different density. It is bent from original path. This ratio of velocity of light in vacuum to its velocity in the substance termed as refractive index of second medium Depending upon purity it is constant for a liquid and can be considered as one of the criteria for its standardization. Refractive index of compound various with wave length of right temperature pressure. Refractive index for some compounds measured using sodium light and a temperature of 25§§§§C are as follows, Arachis oil R.I. is 1.4678 to 1.4698. Caraway oil R.I. is 1.4838 to 14858. Many times drug is identified by its diagnostic characters is of standard quality due to either faulty collection or in correct storage thus to prove its acceptability as a drug following tests can be applied wherever possible.

12. Many times drug is identified by its diagnostic characters is of standard quality due to either faulty collection or in correct storage thus to prove its acceptability as a drug following tests can be applied wherever possible. a)Ash content – The residue remaining after incineration is a ash content of drug. Total ash usually consists of carbohydrates phosphate, silicates and silica. Ex. Aloe total ash is 5 % w/w. Clove total ash is 7 % w/w.

13. Ginger total ash is 6 % w/w. Acid insoluble ash which is part of total ash insoluble in dilute hydrochloric drugs. Adhering dirt and sand may be determined by acid insoluble ash content. Ex. Acid insoluble ash for Agar is 1 % w/w. Acid insoluble ash for clove is 0.75 % w/w. Acid insoluble ash for Cardamom is 3.5 % w/w. b)Extractives – Extracts obtained by exhausting crude drugs are indicative of approximate measures of certain chemical constituents. They contain various solvents are used for determination of extractives solvent used must have ability to dissolve the appreciable quantities of substances. Following are some methods used to find out the extractive values. 1.Water soluble extractives – This method is applied to drugs which contains water soluble active constituents of crude drugs such as tannins, sugar, plant acids, mucilage, glycosides etc. Ex - Aloe -- > 25 % w/w extractives. Glycyrrhizin -- > 2 % w/w extractives. Ginger -- > 10 % w/w extractives.

14. 2.Alcohol soluble extractives – Alcohol is ideal solvent for tannins, resins etc. generally 95 % ethyl alcohol is used for determination of alcohol soluble extractives Ex. Aloe < 10 % w/w extractives Ginger <4.5% w/w extractives , Rhubarb< 30 % w/w extractives Alcohol insoluble extractives are applicable to some resinous drug as Myrrh < 70% w/w extractives, Benzoin < 24 % w/w extractives

15. .Ether soluble extractives -- Two types of ether soluble extractives values determined for evaluation of crude drugs as volatile and non-volatile ether soluble fractions. The volatile ether soluble extractives represents volatile oil content of drug while non-volatile ether soluble extractive represent resin fixed oil or coloring matter present in drugs the limits are applicable for following drugs. Limit for non-volatile ether soluble for linseed is 25 % w/w. Limit for non-volatile ether soluble for cocoa is 22 % w/w. c)Volatile oil content - Efficacy of several drugs is due to their odorous principles ( Volatile oils ) For e.g. Clove contains > 15% w/w vol. oil , Fennel contains > 1.4%w/w vol.oil , Cardamom contains > 4%w/w vol. oils. Different chromatographic techniques such as TLC, HPLC, GC, Column chromatography, Gel Chromatography also technique like IR, NMR, Spectroscopy, Radioimmunoassay are used for physical evaluation.

16. CHEMICAL EVALUATION - It comprises of different chemical tests and chemical assays The isolation, purification and identification of active constituents are chemical methods of evaluation. Quantitative chemical tests such as acid value, saponification value, etc , are also covered under this technique Some of these chemical tests are useful in evaluation of resin (acid value), balsams (acid, saponification and ester values volatile oils (acetyl and ester values) and gums ( methoxy determination and volatile acidity). The preliminary photochemical screening is a qualitative chemical evaluation which indicates spectrum of chemical constituents present in a plant drug. The successive solvent extraction of

17. a drug is carried out with petroleum ether, benzene, solvent ether, chloroform, ethanol and water in succession. The conventional titrimetric estimations as applicable m estimation of alkaloids from crude-drugs, ester and aldehydes contents of volatile oils, gravimetric methods etc , are the techniques f chemical assays The chemical tests also help in proper identification of varieties of the crude drugs. The solutions of lead acetate or lead sub-acetate are used specifically for chemical identity of gums. The alkaloid containing drugs such as rauwolfia , belladonna, ergot, ipecacuanha , etc., and glycoside bearing drugs like senna , digitalis, squill , strophanthus , etc., can be identified with the help of specific chemical tests. The different classes of natural products present as active constituents in crude drugs can be identified by performing several general and specific chemical tests. Halphen's test for cotton seed oil Van Urk's reagent for ergot, Vitalis test for tropane alkaloids Borntrager's test for anthraquinones , murexide test for purine bases a examples of such chemical tests. The estimation of chief constituent or group of active constituent an integral part of chemical evaluation e.g. total sennosides in s morphine in opium, citral in lemon-grass oil, eugenol in clove eucalyptol in eucalyptus oil, water-soluble alkaloids in ergot, tropane alkaloids in belladonna, emetine in ipecac, reserpine and rescinnamine in rauwolfia , quinine in cinchona, etc.

18. BIOLOGICAL EVALUATION - When the estimation of potency of crude drug or its preparation done by means of its effect on living organisms like bacterial. fungal growth or animal tissue or entire animal. It is known as blessay . The method is generally called for, when standardization is not adequatel done by chemical or physical means. In other words, bioassay is the measure of sample being tested capable of producing the biological effec as that of the standard preparation. Such an activity is represented i units known as International Units (I.U) The specific blological activ contained in each IU of few drugs is mentioned as follows: Digitalis 1 IU is contained in 76 mg of standard preparation Vit . A 1. IU is contained in 0.344 micrograms of standard preparation Vit . D - 1 IU is contained in 0.025 micrograms of stand. preparation Heparin 1 IU is contained in 7.7 micrograms of standard preparation. Biological assay methods are mainly of 3 types (1) toxic (1) symptomatic and (i) tasue methods. In toxic and symptomatic techniques, the animals are used, whens in tissue method, the effect of a drug is observed on isolated organ r tissue. Among the drugs that are subjected to bloassay a cada glycosides, vitam hormones, saponins anthracene glycosides a antibiotics (microbiological assay)