Outline industrial preparation, testing, analysis, significance of one pharmaceutical drug

Aspirin

Industrial Preparation

To produce aspirin tablets, corn starch and water are added to the active ingredient which is

acetylsalicylic acid to serve as both a binding agent and filler, along with a lubricant. The

lubricant keeps the mixture from sticking to the machinery. Lubricants that can be used include:

hydrogenated vegetable oil, stearic acid, talc, or aluminum stearate.

The procedure for manufacturing aspirin tablets is known known as dry-

granulation or slugging, this process involves:

Weighing

The active ingredient, cornstarch and the lubricant are weighed separately in sterile

canisters to find out if the ingredients meet pre-determined qualifications for the batch

size and dosage amount.

Mixing

The corn starch is released into cold purified water, heated and stirred until a clear paste

is produced. The corn starch and part of the lubricant are then poured into one sterile

canister; this canister is wheeled to a mixing machine called a Glen Mixer. Mixing blends

the ingredients and releases air from the mixture.

The mixture is then mechanically separated into units. These units are called slugs.

Dry screening

Small batches of slugs are forced through a mesh screen by a hand-held stainless

steel spatula. The large batches are filtered through a machine called a Fitzpatrick mill.

The lubricant that remains is added to the mixture and blended gently in a rotary

granulator and sifter. The lubricant prevents the mixture from sticking to the tablet

machine during the compression process.

Compression

The mixture is compressed into tablets either by a single-punch machine (for small batches) or a

rotary tablet machine (for large scale production). On single-punch machines, the mixture is fed

into one tablet mold called a dye cavity by a feed shoe, as follows:

o The feed shoe passes over the dye cavity and releases the mixture. The feed shoe

then retracts and scrapes all excess mixture away from the dye cavity.

o A punch a short steel rod the size of the dye cavity descends into the dye,

compressing the mixture into a tablet.

Initially, the aspirin mixture is placed into a dye cavity. A steel punch then lowers into the cavity

and compresses the mixture into a tablet after which it’s ejected . As the feed shoe returns to fill

the dye cavity again, it pushes the compressed tablet from the dye platform.

On rotary tablet machines, the mixture runs through a feed line into a number of dye

cavities which are situated on a large steel plate. The plate revolves as the mixture is

dispensed through the feed line, rapidly filling each dye cavity. Punches, both above and

below the dye cavities, rotate in sequence with the rotation of the dye cavities. Rollers on

top of the upper punches press the punches down onto the dye cavities, compressing the

mixture into tablets, while roller-activated punches beneath the dye cavities lift up and

eject the tablets from the dye platform.

Testing

Some of the compressed tablets are subjected to a tablet friability and hardness test in

addition to a tablet disintegration test

Bottling and packaging

The tablets are transported to an automated bottling assembly line where they are

released into clear or color-coated polyethylene or polypropylene plastic bottles or glass

bottles. The bottles are topped with cotton packing, sealed with a sheer aluminum top,

and then sealed with a plastic and rubber child-proof lid. A sheer, round plastic band is

attached to the circular edge of the lid, which serves as an added seal to discourage and

identify if the product has been tampered with.

The bottles are labeled with product information and an expiration date. The bottles are

then packaged appropriately in cardboard boxes. The packages or bottles are then boxed

in larger cardboard boxes in preparation for distribution to distributors.

Ling,G, n.d Aspirin. Retrieved from http://www.madehow.com/Volume-1/Aspirin.html#ixzz375gsO5p4

Testing and Analysis

Aspirin can be analyzed by spectrophotometry and Titration. This is done to determine the amount of aspirin (acetylsalicylic acid) present in the commercial aspirin product.

Spectrophotometry

Method:

Preparing the standard

1. Weigh 400 mg of acetylsalicylic acid in a 125 mL Erlenmeyer flask. Add 10 mL of a 1 M NaOH solution to the flask, heat until the solution starts to boil.

2. Quantitatively transfer the solution to a 250 mL volumetric flask, and dilute with distilled water.

3. Pipette 2.5 mL sample of this aspirin standard solution into a 50 mL volumetric flask. Dilute to the mark with a 0.02 M iron (III) solution. Label this solution "A," and place it in a 125 mL Erlenmeyer flask.

4. Repeat step 3 with 2.0, 1.5, 1.0, and 0.5 mL portions of the aspirin standard. Label these solutions "B, C, D, and E."

Making an unknown from a tablet.

1. Place one aspirin tablet in a 125 mL Erlenmeyer flask. Add 10 mL of a 1 M NaOH solution to the flask, and heat until the contents begin to boil.

2. Quantitatively transfer the solution to a 250 mL volumetric flask, and dilute with distilled water to the mark.

3. Pipette a 2.5 mL sample of this aspirin tablet solution to a 50 mL volumetric flask. Dilute to the mark with a 0.02 M iron (III) solution. Label this solution "unknown," and place it in a 125 mL Erlenmeyer flask.

Testing the Solutions.

1. Turn on the spectrophotometer. Press the A/T/C button on the Spectrophotometer to select absorbance.

2. Change the wavelength to 530 nm by pressing the nm arrow up or down.

3. Insert the blank tube into the cell holder and close the door. Position the cell so that the light passes through clear walls.

4. Press 0 ABS to set the blank to 0 absorbance.

5. Record the absorbance of the solution.

6. Obtain absorbance readings for each of the other standard solutions. Record the results

7. Obtain an absorbance reading for the unknown sample(s).

8. Make a graph of concentration (x-axis) vs. absorbance (y-axis).

9. From the standard curve, determine the concentration of aspirin in the unknown

Sample(s).

Titration

Sample preparation

1. Accurately weigh about 3 aspirin tablets in order tpo determine the average weight of one tablet. Use a mortar and pestle to crush the tablets to produce approximately 1 g tablet powder.

2. Weigh approximately 300 mg of aspirin powder and transfer into a labeled 250 mL Erlenmeyer flasks.

3. Add 20ml of ethanol to each flask and add three drops of phenolphthalein indicator to the flask. Swirl gently to dissolve. (The solution might be cloudy because of insoluble compounds present in tablet)

Aspirin Titration with Base

4. Titrate the first aspirin sample with NaOH to the first permanent cloudy pink color.

5. The aspirin/NaOH acid-base reaction consumes one mole of hydroxide per mole of

aspirin. The slow aspirin/NaOH hydrolysis reaction also consumes one mole of

hydroxide per mole of aspirin, hence for a complete titration use a total

of twice the amount of NaOH that was already used. In addition, some excess

NaOH should also be added to ensure that all of the aspirin in the sample has been reacted.

Heating for Completion of Reaction

6. Heat the titrated solution (in flask) gently in a water bath. Avoid boiling, because the sample may decompose. While heating, swirl the flasks occasionally. After 15 minutes, remove

Samples from the water bath and cool for 5 minutes.

7. If the solution is colorless, add a few more drops of phenolphthalein. If it remains

colorless, add 10 mL more of the base and reheat. (add this additional

volume of base to the previously recorded total volume.)

8. The only base remaining in each flask will be excess base that has not reacted with the

aspirin. Using burette with the 0.1 M HCl solution, titrate the excess base in

each flask with HCl until the pink color just disappears.

9. Record all the volumes of bases and acid in appropriate table.

Significance

Aspirin is one of the safest pain relievers and fever reducer. It is used to combat a wide variety of

health problems including: cerebral thromboses (with less than one tablet a day); general pain or

fever (two to six tablets a day) diseases such as rheumatic fever, gout, and rheumatoid arthritis.

The drug is also beneficial in aiding to protect against heart attacks. Biologists also use aspirin

to interfere with white blood cell action, and molecular biologists use the drug to activate genes.

Tharian,A.(2010). Determination of aspirin in tablets using back titration. Retrieved from

http://www.njit.edu/precollege/docs/RET_2010_Aspirin_in_Tablets_Lesson.pdf