paracetamol
Student number: 658184
Due Date: 19th Sept 2012
Paracetamol: Preparation, Purification and Analysis
1.1 Introduction
Paracetamol (N- (4- hydroxyphenyl) ethanamide) or acetaminophen is a widely used analgesic (pain reliever) and antipyretic (fever reducer). It is a relatively safe drug though toxicity has been observed with very high doses.1 according to the British Pharmacopeia (BP) 111 paracetamol should contain between 95.0%- 105.0% of the stated product.2 It can be synthesised by reacting 4-aminophenol in acetic anhydride and this is often the first stage of preparing a medicine. This experiment aims to prepare a sample of paracetamol and assess its quality and purity as this need to be checked before it can be formulated into a medicine.
1.2 Method
5.10g of 4- Aminophenol was suspended in water, in a quick fit (QF) round bottomed flask in the fume cupboard as 4 – aminophenol is toxic. Ethanoic anhydride (toxic vapor) was added and mixed by swirling and a reflux condenser was attached and fixed onto a clamp stand and heated for ten minutes on a steam bath with occasional swirling. The mixture was cooled at room temperature and further cooled with cold tap water. The crude solid that formed at the bottom of the condenser was vacuum filtered and transferred into a conical 100cm3 flask. A hot plate was used as a heat source to recrystallise the solid from 24cm3 of water. The crystallised product was dried in the oven, spread on a watch glass and weighed and the results recorded.
Next a silica plate was prepared for HPTLC and 0.05g of the crystallised product above was placed into a sample vial which contained 1cm3 of ethyl acetate solvent shaken and dissolved. This sample of synthesised solution and a further two other solutions of pure paracetamol and 4- aminophenol solution sample were separately loaded by capillary action in different positions. These were then placed in a jar containing ethyl acetate (2cm3) and the results were visualized under the UV
Due Date: 19th Sept 2012
Paracetamol: Preparation, Purification and Analysis
1.1 Introduction
Paracetamol (N- (4- hydroxyphenyl) ethanamide) or acetaminophen is a widely used analgesic (pain reliever) and antipyretic (fever reducer). It is a relatively safe drug though toxicity has been observed with very high doses.1 according to the British Pharmacopeia (BP) 111 paracetamol should contain between 95.0%- 105.0% of the stated product.2 It can be synthesised by reacting 4-aminophenol in acetic anhydride and this is often the first stage of preparing a medicine. This experiment aims to prepare a sample of paracetamol and assess its quality and purity as this need to be checked before it can be formulated into a medicine.
1.2 Method
5.10g of 4- Aminophenol was suspended in water, in a quick fit (QF) round bottomed flask in the fume cupboard as 4 – aminophenol is toxic. Ethanoic anhydride (toxic vapor) was added and mixed by swirling and a reflux condenser was attached and fixed onto a clamp stand and heated for ten minutes on a steam bath with occasional swirling. The mixture was cooled at room temperature and further cooled with cold tap water. The crude solid that formed at the bottom of the condenser was vacuum filtered and transferred into a conical 100cm3 flask. A hot plate was used as a heat source to recrystallise the solid from 24cm3 of water. The crystallised product was dried in the oven, spread on a watch glass and weighed and the results recorded.
Next a silica plate was prepared for HPTLC and 0.05g of the crystallised product above was placed into a sample vial which contained 1cm3 of ethyl acetate solvent shaken and dissolved. This sample of synthesised solution and a further two other solutions of pure paracetamol and 4- aminophenol solution sample were separately loaded by capillary action in different positions. These were then placed in a jar containing ethyl acetate (2cm3) and the results were visualized under the UV
References: 1) British Pharmacopoeia Online 2013 [Volume I & II Monographs: Medicinal and Pharmaceutical Substances, Chalk]. Author unknown; 2012 [cited 2012 Oct 29]. Available from: http://www.pharmacopoeia.co.uk/bp2012/ixbin/bp.cgi?a=display&r=0ubZk7MB3KB&id=5525&tab=a-z+index 2) British Pharmacopoeia Online 2013 [Volume III Monograph: Medicinal and Pharmaceutical Substances, Chalk]. Author unknown; 2012 [cited 2012 Oct 29]. Available from: http://www.pharmacopoeia.co.uk/bp2012/ixbin/bp.cgi?a=display&r=j_NFqPYtvUg&n=1&id=5530&tab=a-z+index