Speaking. Complete the following sentence.

1) A tablet shows …..

2) For some other drugs ….

3) The correct pressure…..

4) The most common shape….

5) A tablet meant for making solution ….

6) Tablets which are to be dissolved….

7) It is often found……..

Writing. Translate the following sentences.

1) The tablet is the most common form of medication.

2) Tablets can be made easily from certain drugs.

3) The addition of auxiliary substances is found to be necessary to overcomecertain difficulties in their tableting.

4) The correct pressure must be applied in order to avoid unnecessary complications.

5) Tablets which are to be dissolved slowly in the mouth should be flat for convenience of the user.

6) It is often found that the preparation of deep convex tablets is more difficult.

Writing. Make up your own sentences using the following word-combination.

The most common form; the technique of tablet making; a definite rate of disintegration; the correct pressure; internal administration; powdery substances; excellent improvement properties; unnecessary complications; flow properties.

Speaking.

1) Name special terms of tablet preparation.

2) Name the words relating to shapes and sizes of tablets.

Writing. Fill in the table.

Noun Verb Adjective Adverb

Physical, strength, purely, mechanical, pressure, dissolve, apply, easily, internal, common, prepare, average, generally, require, convex, selection, slowly, hard, user, technical.

Speaking. Put questions to the given answers:

1) - ………….?

– Libricants are added to facilitate smooth ejection of the compressed tablets.

2) - ………..?

- A tablet is desintegrated when brought into contact with water.

3) - ………?

– The application of different pressure during tableting plays a very important role.

4) -……………?

-Greater amounts of lubricants and glidants are used by an increase in pressure.

5) -…………….?

- The use of starch in tablet making has been known for a long time.

Speaking. Answer the following questions:

1) What is the most common form of medication for the administering of drugs in a dry state?

2) In what state is a certain volume of a drug subjected to pressure in a die during the process of tabletting?

3) What is a tablet characterized by when brought into contact with water?

4) What substances are used for tablet making?

5) Are any auxiliary substances added to the above mentioned substances?

6) To what drugs is it necessary to add auxiliary substances?

7) Why are some difficulties experienced in the process of tabletting?

8) What is necessary to do in order to avoid unnecessary complications during tableting?

9) What kind of tablets must be strongly compressed?

10) What substances improve the flow properties of the tablet materials?

11) What facilitates smooth ejection of the compressed tablets?

Writing. Write an annotation to the text Preparation of tablets. Shapes and sizes of tablets.

Work-out for practical study

Theme: «Drug extraction»

Pre-reading task. Speaking.

5) What do you know about drug extraction?

6) What instruments are used in drug extraction?

7) Can you describe the process of extraction?

List of new words

Maceration viscosity

Percolation adhesion

digestion fruction

infusion osmosis

decoction soluble principles

Reading. Text “Drug extraction”.

Drug extraction

The principle modes of extraction employed in pharmacy at present are as follows: 1. Maceration 2. Percolation 3. Digestion 4. Infusion 5. Decoction.

Of these percolation is the most important and useful.

Maceration and digestion, which is merely a modified from of maceration, are old processes.

The process of maceration consists simply of extraction by soaking the drug or substance in the menstruum until the cellular structure thoroughly penetrated and the soluble portion softened and dissolved.

The usual method is to introduce the drug into a bottle with the solvent, stopper it tightly, and agitate it occasionally for a period ranging from 2 to 14 days, then to pour off the liquid, express the residue to avoid loss, and filter the mixed liquids. The drugs are macerated in definite quantities of menstruum, which consists of alcohol of various strengths, ether and alcohol, or other specified solvent.

Percolation, or lixiviation, is the extraction process in which a granulated or powdered drug is deprived of its constituents by the descent of a suitable solvent through it.

The physical forces playing an important part in percolation are gravitation, viscosity, adhesion, friction, osmosis, capillarity, surface tension, and solution.

The instrument used to hold the powder is called a percolator, the liquid poured on top of the powder, the menstruum; the liquid coming from the percolator, the percolate; and the residual drug remaining in the percolator after the extraction of the soluble constituents, is called the mare.

In order to understand thoroughly the process of percolation as applied to powdered drugs, it must be remembered that the soluble principles of vegetable substances are in hard and dry condition, and are generally contained in cells which are more or less disintegrated by the process of grinding. If the soluble principles could be separated from the insoluble cellular substance and be deposited in the ground particles, percolation would be rapid.

But the powdering of the drug only partially separated the soluble principles from the insoluble and the finest dust of the powder always contains a large proportion of the soluble principles than of the insoluble substance. Hence the first proportion of the percolate is usually the most dense, the most highly coloured, and contains the largest proportion of the soluble principles.