Pharmaceutical Chemistry Chapter 1 Notes PDF

Diploma in pharmacy 1st year NOTES Pharmaceutical Pharmaceutic Chemistry This is an Education Platform We provide Free PDF Notes and Videos Classes for Phar...

Diploma in pharmacy 1st year NOTES Pharmaceutical Pharmaceutic Chemistry This is an Education Platform We provide Free PDF Notes and Videos Classes for Pharmacy Students Web Site http://www.fdspharmacy.in/ You tube https://www.youtube.com/channel/UC77iEsiuZ0lU4pB8WAJIR5Q What app https://chat.whatsapp.com/IzSgXtFEvhS4LN5xhUgq5z Telegram https://t.me/+cvxm17xSloA4MjVl Face book https://www.facebook.com/Fdspharmacy https://www.facebook.com/Fdspharmacy-105764311994440/ E-mail [email protected] Page | 1  Diploma in Pharmacy 1st Year Pharmaceutic Pharmaceutical Chemistry Chapter 1 : Introduction ntroduction to pharmaceutical chemistry Topics Page No Pharmaceutical chemistry 3 Objective Scope Source and Types of Errors 4 Accuracy Precision Significants Impurities in pharmaceuticals 5 Limit Tests for Chlorides, Sulphates, Iron, Heavy Metals, 6 and Arsenic. Page | 2  pharmaceutical armaceutical chemistry Chapter 1 INTRODUCTION TO PHARMACEUTICAL CHEMISTRY Pharmaceutical chemistry  The chemistry which studies about the drug design and synthesis of biologically active molecules is known as pharmaceutical chemistry  Pharmaceutical Chemistry involves development and the study of drugs , Drug discovery, Metabolism, absorption, delivery etc. are included in this Careers  Pharmacetical companies  Biotechnology companies  Drug development & research facilities etc. Objective Its main aim is to ensure the fitness for the purpose of medicinal products by analsing and evaluating them as per the quality control standards Following are some objectives of pharmaceutical chemistry  To enhance the knowledge wledge base required for synthesis, Isolation, Purification  To enhance Skill for effective handling of chemicals, glasswear etc.  To provide proper qualities and skills to the students required to fulfill their job responsibilities as chemist  To train the students about effect of chemicals Scope Skills required in pharmaceutical chemistry  Good writing and verbal communication skills  Synthetic organic chemistry skills  Ability to purify drugs and intermediates  Spectoscopic techniques  Understanding of biological roles drugs  Team work and interpersonal skills  Good communication skills etc. Page | 3 ERRORS Error is a mistake but rather a difference between a computed / estimated measured value and the accepted true / specified / theoretically co correct value Classification of error  Systematic / Determinate / Non random errors  Non systematic / Indeterminate / Random / Accidental errors  Gross error 1) Systemic error :- The error is constant or changes slightly bu consistent fault during the analysis. Eg : - error in titration  Instrumental error :-- Error occurs due to faulty instrument or reagent containing impurities  Operational / Personal ::- When error occur during operation or carryout the experiment is calles as operational error  Methological error :-- These error are most serious errorrr of analysis most of above error can be minimized or corrected but errors that are not changeable unless the condition of the determinations are alterted. Eg : Errors occer due to co-precipitation precipitation of impurities 2) Non-systematic error :- The error unpredictable and difficult to identify Source  Presence of bubbles in burette  Sample handling improperly 3) Gross error :- These error are a combination of both systematic and non-systematic systematic error They are the result of big mistake made during analysis and can be identified easily Gross error is also known as Avoidable mistake Source  Calculation error  Wrong sample sizes  Mix up of samole / reagent  Transcription error Page | 4  Accuracy and Precision Accuracy :- It can be said that the difference between calculated value and accepted real value is known as accuracy Precision :- Reproducibility or Re Repeatability peatability can be defined as the precision of measurement system in which the degree of repeated measurement is considered under the static condition given the same result Repeatability :- It is the variation which arise in spite of all the efforts made to keep the condition constant wheather relased to instrument and repeating in short term span Reproducibility :- It is the variat variation ion which arise by applying the same process for the measurement by using different instrument and operators over a longer time span Significant figure The significant figure of any number are the digits that add up to the precision Rule  Non – zero digits its are significant Eg : 89, 56,78,etc  Zero between teo non – zero digits are significant Eg : 108, 805 etc  Leading zero are consider insignificant Eg : 0.00098, 0.000643 etc  Trailing zeros after a decimal point are significant Eg : 12.7900, 6.900 etc Impurities in pharmaceuticals An impurities is generally considered as an there vario various us organic material except the other drug substance that arises during the manufacturing process process. Raw material employed in manufacture ::- Impurities resulting from raw material many affect the process of manufacture and contaminate the resultant product Eg: Calcium sulphate & magnesium chloride present rocksalt some amount of calcium & magnesium will present in sodium chloride Page | 5 Reagents used in the manufacturing process ::-The impurities from the reagents may contaminate the final product uct if they are not washed away properly. Eg : Mixing mercuric chloride solution with dilute ammonia solution result in ammoniated HgCl2 + 2NH4OH NH2Hgcl + NH4cl + 2H2O Ammonium hydroxide present in the final product Process used in manufacture :- Different manufacturing process are used for producing many drugs and chemicals during there process of manufacturing, some impurities get an access into the materials  Formulation related impurities  Synthesis intermedicates & bypro byproduct  Residual solvent  Method related impurities  Chemicals process used in manufacture Environment related impurities :--Atmosphere in industial areas is adulterated with gases like Hydrogen, sulphide, smoke,etc  Exposure to adverse temperature  Uv ligits  Humidity Effects of impurities in pharmacopoeial substance A little amount of impurities always remain in a material  After a certain period , even a minute quantity of impurite cause toxic effect  Impurities also bring about technical difficulties in the formulation  Impurities also reduce the self self-life of a substance  Some impurities result in incompatility with other substance  Impurities also effect in physical and chemical properties of substance Limit tests Quantitive tests intended for identifying and controlling small quanties of impurities which may occer in a substance are termed as limit test Limit test used for :- 1. Finding out the quantity of harmful impurities 2. Finding out the quantity of avoidable impurities Page | 6  Arsenic This test is carried out for controlling the arsenic impurities on inorganic substance Principal :- The limit test for arsenic is based on the reaction in which arsenic is converted in arsine ( AsH3 ) by undergoing reduction with zinc and hydrochloric acid. The use of Stannated hydrochloric acis is prescribed in the I.P H3Aso4 H3Aso3 Arsenic Acid Arseneous Acid H2Aso3 + 6H2 AsH3 + 3H2o Arsine When arsine comes in contact with dry paper daturated with mercuric chloride | bomide it produce a yellow or brown stain 2AsH3 + Hgcl2 Hg AgH2 + 2Hcl AgH2 The intensity of the colour lour produce is proportional to the amount of arenic present, if the diameter of the paper exposed to arsine os constant The test solution of the sample is compared with the standard solution with known amount of arsenic The strain are the compared in na natural light Apparatus : Rubbercork,springclip,mercuric chloride,paper,200mm long glass tube with 8mm external diameter 200mm, etc Procedure : Test solution : The test solution is prepared as directed in the mo monograph nograph and placed in the generator bottle 5 ml of 1m potassium iodide, 5ml of stannous chloride acid solution and 10gm of zinc AsT are added to the test solution A test paper of mercuric chloride is placed in the rubber slit and the bottle is immediately stopped. The reaction is allowed to continus for 40 min at above 40 oc. Page | 7 Standard solution : 0.33 gm of arsenic triocide is dissolved in 5 ml of 2m NaOH solution and volume is made up to 250 ml with water 1ml of this solotion is further diluted with distilled water up to 100 ml The stain produced by the test sample passes the test if the stain produced by it is less intense than that of the standard solution Chloride Limit test of chloride This test is carried out for identifying the chloride ions present in a standard solution Principal  The limit test for chloride is based on a reaction that occurs between silver nitrate and soluble chloride which is insoluable in dilute nitric acid.  The test solution appears turbid due to the formation of silver chloride in the presence of dilute nitric acid. Amount of chloride present in the test samples influences the degree of turbidity.  Test solution is compared with the standard solution.  By viewing transversly through both the solution against a black background in nessler’s cylinder is compared the samples passes the limit test if the test solution is less turbid than the standard solution and fails in vice versa condition. Procedure In this limit test a standard solution and test solution is prepared and then the appearance of there two solution is compared Test solution :- 1.0 gm of sample is aaccurately ccurately weighted and transferred to nessler cylinder dislove in 10 ml distill water. 1 ml of nitric acid is added to this sol and volume up to 50 ml with distill water. 1 ml of silver nitrate be added to the solution stirring for 5 min after which turb turbidity idity develop Specified substance ( 1gm ) + 10 ml of water + 1 ml of nitric acid + water up to 50 ml + 1 ml silver nitrate turbidity Standard solution :- 1 ml of 0.01 m Hcl is mixed with 1 ml of nitric acid in nessler cylinder B and volume up to 50 ml with distill water. 1 ml of silver nitrate solution which produce turbidity after 5 min The sample passes the limit test if it is less turbid than the standard solution Page | 8  Sulphate Limit test for sulphate This test is carried out for controlling the sulphate impurity in inorganic substance Principle In the limit test for sulphate, barium chloride reacts with soluable sulphate in the presence of dilute Hcl solution. The resulting turbid solution is compar compareded with the standard solution of acceptable limit. The barium sulphate reagent contain barium chloride , sulphate free alcohol, and potassium sulphate Procedure Test solution :- 1 gm of sulphate is weighted and 2 ml of Hcl is added to 45ml of solution. solution 5 ml of BaSo4 reagent is added to prepare the solution Standard Solution : 1 ml of 0.1089 % w/v solution of K 2So4 is weighted and treated with 2ml of Hcl. This solution is diluated up to 45 ml.At the last the standard solution is prepared by adding 5 ml of BaSo4 reagent The limit test off sulphate is passes if it is lless ess turbid than the standard solution Iron Limit test of Iron This test is carried out for controlling the iron impurities in inorganic sunstance Principle:- The limit test for iron relies on the reaction in which iron reacts with thioglycollic acid in a solution. With ammonium citrate buffer It results in the formation of a purple colour solution due to the formation of mercaptoacetate This purple urple colour is compared with the standard colour containing a known amount of iron Procedure Test solution :- 40 ml of water is added to the sampleand treated with 2 ml of 20% w/v citric acid.Then 2 drop of thioglucollic acid is added the solution is m mixed ixed made alkaline with ammonia , and Page | 9 volume made up to 50 ml. Then the solution is allowed to stand for 5 min so that a colour develop which is viewed vertically & compared with the standard solution Standard solution :- 40 ml of water is added to 2 ml of standard solution of iron.Then 2 ml of 20 % w/v citric acid and 2 drop of thioglycollic acid is added to the solution the solution is made alkaline with ammonium and volume is made up to 50 ml.The solution is allowed to stand for 5 min so that a colourr develop which is viwed vertically and compared with the test solution When the colour of both the solution is compared the intensity of the colour of the test solution should be less than that of standard solution Heavy Metals Limit test for Heavy metals This limit test is carried out for determining the content of metallic impurities coloured by sulphide ion , under specific condition Principle:- Limit test for heavy metals are based on the reaction between a solution of a heavy metals and a saturated solution of H2S in an acidic medium A reddish / black colour resulted is compared with the standard solution of lead nitrate solution Procedure:- Test solution :- 25 ml of test solution is prepared in a 50 ml of nessler cyli cylinder nder and ph is adjusted between 3-44 using dilute acetic acid or dilute ammonia solution , After PH adjustment the solution is diluted up to 35 ml with water Standars solution :- 2 ml of standard lead solution is prepared out in a 50 ml nessler cylinder and an diluted up to 25 ml with water. The pH is adjusted between 33-4 4 using dilute acetic acid pr dilute ammonia solution After pH adjustment the solution is diluted u to 35 ml with water After that 10 ml of freshly prepared hydrogen sulphide solution is add added ed into both the cylinder containing standard solution and test solution and diluted up to 50 ml with Water.After dilution the solution is krpt aside over a white surface for 5 min and viewed down wards the test solution colour is lighter than the standars solution colour Page | 10 Page | 11