Preparation and evaluation of Aspirin tablets
BP506P Industrial Pharmacy I Practical
Aim: to formulate and evaluate the aspirin tablets
Materials required apparatus:
Mortar and pestle, beaker, sieve # 10, tablet punching machine, hot air oven.
Chemicals: aspirin, lactose, dry starch, magnesium stearate, and talc.
Theory:
Aspirin has analgesic and antipyretic properties but it has no useful anti-inflammatory properties. Aspirin is readily absorbed from the gastrointestinal tract. Aspirin is categorized under bcs classification ii tablets are solid dosage forms containing one or more drugs with or without excipients, prepared by compression. It provides excellent dose precision and the least content variability. Inert materials employed in addition to active ingredients are collectively called tablet additives. They include
- Diluents: are fillers designed to make up the required weight of the tablet. Eg: lactose, inorganic dicalcium salts microcrystalline cellulose etc.
- Binding agents: are added in dry or in liquid form to obtain cohesive mass for direct compression. Eg: cellulose derivatives, gelatin solution, glucose syrup, tragacanth mucilage etc.
- Disintegrating agents: are added to facilitate breakup of the tablet when in contact with gastrointestinal fluids. Eg: dry starch, starch derivatives, clays, cellulose, cellulose derivatives, and alginates
- Adsorbents: included when formulation contains liquids, volatile oils etc.
- Anti-frictional agents: enhance flow properties. Eg : talc, corn starch, silica derivatives etc.
The usual methods of formulation include wet granulation, dry granulation and direct compression. The most widely used and most general method of tablet preparation is the wet granulation method. The active ingredient, diluent and disintegrents are mixed or blended well. Solutions of the binding agent are added to the mixed powder with stirring. The powder mass is wetted with the binding solution until the mass has the consistency of damp snow. If the granulation is over wetted the granules will be hard, if not wetted sufficiently, the resulting granules will be too soft, breaking down during lubrication. The wet mass is forced through a 6 or 8 mesh (mesh no. Is the number of wires passing through an inch) screen or several mills can be used .moist materials from wet milling steps is placed on large trays and placed in drying chambers with a circulating air current and thermostable heat controller. Commonly used dryers are tray dryer, fluidized bed dryer. After drying, the granulation is reduced in particle size by passing smaller mesh screen. After drying granulation, the lubricant or glidants is added as fine powder to promote flow of granules. These granules then compressed to get tablet
Formula for Design of Aspirin Tablets
| Ingredients for | 1 tablet(mg) | For 40 tablets(g) |
| Aspirin (drug) | 300 | |
| Lactose (diluent) | 375 | |
| Drystarch(binder &disintegrant) | 48 | |
| Talc (glidant) | 40 | |
| Magnesium stearate(lubricant) | 12 | |
| 5%starch was used as the binding agent. | Qs |
The tablets was granulated using wet granulation method as follows.
Aspirin, lactose and half the quantity of starch were weighed and mixed thoroughly. It was granulated using 5% starch mucilage as binding agent and passed through no.10 mesh screen. The obtained the granules were dried at 55ᵒc for 1 hr. After drying, dry screening was
done using no.22 mesh screen. The rest of the starch powder along with talc and magnesium stearate were added and mixed. These granules were compressed into tablets on a 16 station cadmach rotary tablet machine (12mm).
Evaluation of tablets
Hardness test: tablet hardness was measured using monsanto hardness test apparatus.
Weight variation test: 20 tablets are weighed individually. Calculated the average weight and individual weight are compared with the average weight.
Friability test: friability is a measure of mechanical strength of the tablet. If a tablet has more friability it may not remain intact during packaging, transport or handling. Roche friabilator is used to determine the friability by following procedure. Pre weighed tablets are placed in the friabilator. Friabilator consist of a plastic chamber that revolves at 25 rpm, dropping those tablets at a distance of 6 inches with each revolution. The tablets are rotated in the friabilator for at least 4 minutes. At the end of test tablets are dusted and reweighed; the loss in the weight of tablet is the measure of friability and is expressed in percentage as: % friability = 1‐ (loss in weight / initial weight) x 100
Assay: 20 tablets are powdered and weighed. A quantity of powder equivalent to about 0.15g of aspirin are accurately weighed and added 50ml of 0.1m sodium hydroxide, diluted with 100ml of water, and shake for 15 mins and added sufficient water to produce 250ml. They are mixed filtered and diluted 10ml of the filtrate to 100ml with water. To 10ml of resulting solution 10ml of 0.1m sodium hydroxide are added and diluted to 100ml with water and mixed. The absorbance of the resulting solution at the maximum at about 257nm were measured by using uv-visible spectroscopy.
Disintegration study experimental conditions were: medium: water speed: 30cycles/minute
temperature: 37±0.5ᵒc one tablet was added into each of the 6 tubes of the apparatus and the assembly was suspended in a beaker containing water and time required to disintegrate each tablet was noted. From this average disintegration time was determined.
Dissolution study: the study was carried out using type-2 paddle type usp apparatus. The set condition was 900ml of 6.8ph phosphate buffer, at 50 rpm, 37ᵒc for 45 minutes, 5ml of samples were withdrawn at time intervals of 5, 15, 30, 45 minutes, which was replaced by
fresh equal volume of dissolution medium, the sample was diluted suitably, assayed at 280nm by using uv-visible spectroscopy. The calibration curve was used to determine the drug concentration per ml. The amount of drug release was calculated using calibration curve
method. Amount of drug release = 𝑐𝑜𝑛𝑐.×𝑣𝑜𝑙.𝑜𝑓.𝑑𝑖𝑠𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛𝑚𝑒𝑑𝑖𝑢𝑚×𝑑𝑖𝑙𝑓𝑎𝑐𝑡𝑜𝑟 1000 percentage drug release = 𝑎𝑚𝑜𝑢𝑛𝑡𝑜𝑓𝑑𝑟𝑢𝑔𝑟𝑒𝑙𝑒𝑎𝑠𝑒𝑠𝑡𝑟𝑒𝑛𝑔𝑡ℎ x 100 report the formulation
and comparative evaluation of marketed aspirin tablets was performed.
Industrial Pharmacy I Practical
- Preformulation studies on paracetamol/aspirin/or any other drug
- Preparation and evaluation of Paracetamol tablets
- Preparation and evaluation of Aspirin tablets
- Coating of tablets- film coating of tables/granules
- Preparation and evaluation of Tetracycline capsules
- Preparation of Calcium Gluconate injection
- Preparation of Ascorbic Acid injection
- Quality control test of (as per IP) marketed tablets and capsules
- Preparation of Eye drops/ and Eye ointments
- Preparation of Creams (cold / vanishing cream)
- Evaluation of Glass containers (as per IP)
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