Percolation

Q: What is percolation?

Ans: Percolation is the package of the raw material into a column and the solvent is allowed to percolate through it.

Although some materials may be packed into a percolator in the dry state e.g. Ginger, most drugs require preliminary moistening.

Q: What is the principle of percolation?
Ans: It is a process in which a comminuted drug is extracted of its soluble constituents by the slow passage of the suitable solvents through the column of a drug.

Q: What do you know about percolator and percolate?
Ans: The drug is packed in a special extraction apparatus termed as percolator with the collective extractive called the percolate.

Q: What is preliminary moistening?
Ans: The solid material is mixed with sufficient amount of solvent and the moist mass is allowed to stand for 4 hours in a well-closed vessel. This is preliminary moistening.

Q: Why preliminary moistening important?
Ans: This preliminary moistening is important because the dried tissues may swell on contact with the solvent and if packed in the dry condition subsequent swelling might decrease the porosity of the material and choke the column.

Preliminary moistening also makes the fine particles less liable to be washed out of the column during percolation.

Q: Defined the methods of percolation?
Ans: There are two methods of percolation which are given below:

• Commercial scale

• Small scale

Q: What is the commercial method for the percolation?
Ans: The drug is supported on a preforated metal plate covered with sacking or straw. The top of the apparatus is removable and provided with portholes for inspection and running in of solvent. At the base the outlet is fitted with a tap and a pipe leads the top of a second percolator in order to use the solvent more efficiently.

Q: What is the small scale method for percolation?
Ans: On small scale glass percolators can be used and the raw material is supported in a loose plug of tow or other suitable substance which has been previously moistened with solvent.
Q: What is reserved percolation?
Ans: Liquid extracts are more concentrated preparations than tinctures and percolation to exhaustion will produce a preparation that is much diluted. It is therefore necessary to decrease the volume of the percolate by evaporation.

In certain instances such as in Liquorice Liquid Extract, the whole of the percolate may be concentrated by evaporation.

Q: How Ipecac syrup is prepared?
Ans: Ipecac syrup is prepared by percolation. It is prepared by adding glycerin and syrup to an extractive of powdered ipecac obtained by percolation.

The drug ipecac which consists of the dried rhizome and roots of Cephaelis ipecacuanha containing emetine, cephaeline and psychotrine. These ingredients are extractive from the powdered ipecac by percolation with the hydro-alcoholic solvent.

Further Reading:
Remington: The Science and Practice of Pharmacy (Remington the Science and Practice of Pharmacy)

British Pharmacopoeia 2010

Textbook of Pharmaceutics

Extracts

Q: Define Extract?

Ans: Extracts are defined as concentrated preparation of vegetable or animal drugs obtained by removal of active constituents of the respective drug with menstruum, evaporation of all or nearly all of solvent, and adjustment of the residual masses or powders to the prescribed Standards.

Q: How many types of extracts are there?
Ans: There are three types of extracts:

• Semi liquid

• Solid extracts (Plastic masses)

• Powdered extracts (Dry powder)

Q: How the extracts are mostly prepared?
Ans: Mostly, extracts are prepared by extracting the drug by percolation.

Q: Why extracts are to be protected from heat?
Ans: The use of heat is avoided where possible because of potential injurious of active constituents

Q: Give some examples of extracts.
Ans: The examples of extracts are

• Extracts of Pure glycyrrhiza

• Extracts of Belladonna

Q: Define Fluid Extract?
Ans: USP define Fluid extract as being preparation of vegetable drugs containing alcohol as solvent or as a preservative or both, so that unless otherwise specified in an individual monograph, each milliliter contains the therapeutic constituents of 1g of the standard drug it represents.

Q: How unwanted colloidal material is separated and removed from fluid extract?
Ans: The fluid extract can be separated from the oil, concentrated by evaporation and re-extracted with strong alcohol to removed unwanted colloidal material.

Q: How degradation of fluid extract can occur?
Ans: Fluid extracts are subject to degradation by enzyme action.

Q: How degradation by enzyme is inhibited?
Ans: This can be inhibited by including alcohol to give a concentration of 25% or more but enzyme is not destroyed and concentration must be taken to avoid subsequent condition in which the enzyme activity can be restored.

Q: What are the Solvents and their advantages used in fluid extract?
Ans: Solvents used in fluid extract are

• Alcohol

• Water

• Solvent ether

• Acetic acid

Advantages of water and/or alcohol:

• It is cheap.

• It is non toxic.

• It can dissolve wide range of chemical substances.

• It flame and non-flamable.

Further Reading:
Remington: The Science and Practice of Pharmacy (Remington the Science and Practice of Pharmacy)

British Pharmacopoeia 2010

Infusion, Decoction and Tisane

Q: What is infusion? And also write some examples.

Ans: Infusions are liquid preparations, which are either prepared by infusion process or by diluting 1 part of concentrated infusion with 9 parts of water OR An infusion is the outcome of steeping plants with a desired flavor in water or oil.

Examples:

• Concentrated compound gention infusion.

• Concentrated senega infusion.

Q: What type of appratus is used in the preparation of infusion?
Ans: The simplest form of apparatus consists of BEAKER or a TEAPOT but special pots known as INFUSION POTS can also be used.

Q: How infusion is extracted?
Ans: The drug to be extracted is placed at the bottom of the pot, water is added and the content stirred occasionally or the drug may be enclosed in a piece of MUSLIN and suspended just below the level of the water.

The drug is allowed to remain in contact with water for the required time, which is usually 15 minutes. After the specified time, the liquid is strained and dispensed.

The marc is not pressed to avoid expression of colloidal cells into the final. Volume of the preparation is not adjusted by adding more of the vehicle otherwise dilution of active constituent will take place.

Q: How many types of infusion are used?
Ans: There are two types of infusion

• Freshly prepared infusion

• Concentrated infusion

Q: What do you know about the two types of infusions? And also give their examples.
Ans: 1. Freshly prepared infusion:

These must be used within 24 hours of its preparation.

Examples:

• Infusion of Senna.

• Infusion of quassia.

2. Concentrated infusion:

This infusion must be prepared by maceration or percolation process and alcohol is also used as a menstruum or a preservative.

Example:

• Concentrated infusion of Chirata.

• Concentrated infusion of gentian.

Q: What do you mean by decoction?
Ans: It is a method of extraction by boiling of dissolved chemicals, or plant material, which may include stems, roots, bark and rhizomes.

Decoctions differ from most teas, infusions, or tisanes in that they are usually boiled. The term is used colloquially in South India to refer to black coffee prepared by the traditional method.

Q: What is the etymology of decoction?
Ans: The term dates back to 1398, from present participle stem of Latin decoquere, (meaning to boil down), from de- + coquere "to cook".

Q: Write about process of decoction.
Ans: Decoction involves:

• First mashing and

• Then boiling in water to extract oils , volatile organic compounds and other chemical substances.

Q: How decoction is done in herbalism?
Ans: In herbalism, decoctions are usually made to extract fluids from hard plant materials such as roots and bark. To achieve this, the plant material is usually boiled for 8–10 minutes in water. It is then strained.

Q: What do you mean by tisane?
Ans: It is a type of infusion of flowers and leaves used in the form of herbal beverages such as herbal tea.

(This blog will help you in the preparation of Pharmacy Exams)

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Interesting books on Ancient medicines:

Aromatic Waters

Q: What are aromatic waters?

Ans: Aromatic waters are saturated solutions (unless otherwise specified) of volatile oils or other aromatic or volatile substances in distilled water. They are usually employed for flavoring. They are clear and free from solid impurities.

Q: Classify aromatic waters?

Ans:

• Simple aromatic waters

• Concentrated aromatic waters

Q: What do you know about concentrated aromatic waters?

Ans: These products are alcoholic, non-aqueous preparations containing 2% of volatile oils. They are forty times stronger than the ordinary aromatic waters. Many volatile oils contain aromatic part and non-aromatic part. The aromatic portion is much more soluble in a weak alcohol than the non-aromatic portion.

Q: What do you know about camphor water?

Ans: They are made by mixing racemic camphor with ethanol and by adding sufficient amount of water.

Q: What are the uses of camphor water?

Ans: Camphor water has been used as the vehicle in ophthalmic solutions owning to its ability to contribute refreshing, stimulating effect to the preparation.

Q: How aromatic waters smell?

Ans: They possess an odor similar to the plant or volatile substance from which they are made. They are free from foreign odor.

Q: How aromatic waters should be stored?

Ans: Aromatic water deteriorates with time and it should be made in small quantities and protected.

(These Viva Type Questions will help you to prepare for Pharmacy Exams)

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Interesting books:

Tinctures

Q: What are tinctures?

Ans: These are alcoholic or hydroalcoholic solutions made from materials of plant origin or from chemical substances. Most of the tinctures are prepared by percolation or by maceration.

Q: What is the method generally used for the preparation of tinctures?
Ans: Herbs are placed in a container and a spirit containing 40% pure ethanol is added. The jar is placed for 2-3 weeks and shaken occasionally so that the concentration can be increased of the solution.

Q: What are the examples of tincture?
Ans: Iodine tincture, alcoholic tincture, digitalis tincture, belladonna tincture

Q: What do you know about iodine tincture?
Ans: It is a hydroalcoholic solution having

• Elemental iodine i.e. 2%,

• Potassium iodide i.e. 2.4%, so that the dissolution is facilitated and

• Alcohol i.e. 47%.

Q: What is the use of iodine tincture?
Ans: It is used as an antiseptic/germicide for scratches and cuts on the surface of the skin. It has been used as a skin disinfectant before surgery but is now largely replaced by organic forms of iodine.

Q: What do you know about belladonna tincture?
Ans: It is a green hydroalcoholic liquid having the alkaloids scopolamine and atropine and other substances that are extracted from the leaves of Atropa belladonna.

Q: What is the use of belladonna tincture?
Ans: Earlier it was widely used in treatment of ulcer or the palliative treatment of diarrhea, either alone or in combination with antacids and insoluble clays.

Q: What do you mean by palliative treatment?
Ans: It means the relief of mental and physical pain or symptoms without actually treating the causes, especially in patients suffering from a fatal (dying) illness.

(These Viva type Questions can help you in the preparation of pharmacy exams)
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Further Reading:

Surface tension

Q: What do you mean by surface tension?

Ans: It represents the intermolecular attraction due to cohesive quality at the surface of the liquid, in contact with another fluid or solid, which tends to move the molecules of the liquid inside from the surface.
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Further Reading:

Some viva questions from Pharmacognosy

Q: What do you know about ergot alkaloids?
Ans: These include alkaloids which we get from the ergot fungus Claviceps purpurea or derived semisynthetically.

Q: Give examples of ergot alkaloids?
Ans: Ergotamine, dihydroergotamine, ergonovine, methysergide, lysergic acid diethylamide (LSD).

Q: What do know about Glycoside?
Ans: It represents a derivative of sugar that decomposes into a sugar and non-sugar component. It is obtained by extraction of crude drug with alcohol. For example digitalis glycosides.

Q: What do you mean by essential oils?
Ans: These are the products obtained from plant having volatile nature. They represent the taste and odour of that particular plant from which these are obtained such as camphor, menthane and terpenes.

Q: What do you mean by antibiotic?
Ans: It represents a soluble substance which is obtained from bacterium or mold (fungus) having the ability of stopping the growth of micro-organisms. They are inactive against viruses.

Q: What do you know about vaccine?
Ans: Vaccine represents a product, having dead or weakened micro-organism of kind causing a specific disease, used to stimulate the immune system for the production of antibodies in competition with that specific disease.
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Further Reading: