Interpretation of Prescriptions

 

Compounding

Interpretation of Prescriptions

Prescription is an order signed by a licensed medical practitioner directing the pharmacist to compound and dispenses a medicament.

A complete prescription includes the following:

1.   Prescriber’s office information

2.   Date of the prescription was written

3.   Name of the patient and address

4.   Superscription: contains the traditional symbol Rx meaning you take

5.   Inscription: contains  the list of ingredients and their quantities

6.   Transcription: contains the necessary directions to be labeled on the container for use by the patient.

7.   Name  of the prescriber or his  initials

Labeling

The label on dispensed medicine should provide the patient with all the information necessary so that the medicine may be taken or used appropriately.

Information on the label includes:

1.   Patients name

2.   Name  and address of pharmacy

3.   Date of dispensing

4.   Name, strength and quantity of  the preparation

5.   Direction for use

6.   Storage condition and shelf life ( expiry date)

7.   Cautionary and advisory labels.

The information on the labels of dispensed medicines should be accurate legible intelligible adequate and relevant.

1.   Accurate: the label should be checked immediately after writing and again prior to fixing to container.

2.   Legible:- the  label should be type written or printed or written neatly  with pen

3.   Intelligible: the information should be completely unambiguous and arranged to avoid confusion. The terms should be readily understandable by the lay person.

4.   Adequate and relevant: care should be take to avoid causing confusion and anxiety. Too much information on the label may mean that none of it is noted.

Note that the size of the label should be related to the size of the container.

Formulation of liquid dosage forms

·         Dosage forms are the means by which drug molecules are delivered to sites of action within the body.

Types of dosage forms

·         Base on the physical  nature  of the products dosage forms are  classified into 3 groups

1.   Liquid dosage forms: - solution, suspension and emulsions.

2.   Semi –solid dosage forms: - ointments pastes, creams, jellies.

3.   Solid dosage forms: - powders, granules capsules, tablets, suppositories etc.

Solutions

Solution are homogenous liquid  preparation containing  one or more  dissolved ingredients and are used for a variety of purposes as  both internal and external dosage forms.

1.   Solution taken orally:- mixtures, elixirs, syrups, linctuses draughts

2.   Solution used in mouth and throat: - mouth washes and gargles, throat paints, throat sprays.

3.   Solution instilled into body cavities: douches, enemas, eardrops, eyes, drops, nasal drops, nasal sprays.

4.   Solution applied to body surface: collodions, liniments, lotion and paints.

·         In addition to the active ingredient (medicaments), solutions also contain vehicles and adjuncts.

·         The vehicle is the medium in which the ingredient of a   medicine are dissolved or dispersed for solution this is the solvent.  E.g. water, aromatic waters, alcohol, glycerol, syrup, etc.

·         Water is the vehicle of choice for the majority of pharmaceutical solution. Because water is generally available, relatively inexpensive, palatable and non- toxic for oral use and non irritant for external use. It also acts as a solvent for a wide range of substances.

·         The adjuncts are additives that are added to improve the quality of the preparations. E.g. chemical stabilizers, colorants, flavorants, preservatives, etc.

General procedure for compounding

Performance Criteria- 

1. Wear personal protective (Gowon, Masks, Glove, etc) & hand washing.

2. Clean work row material and Ingredients

3. Collect row material and equipments

4. Tare bottles

5. Correct calculation

6. Weighing technique use of paper or watch glass

7. Measuring technique

8. Mixing /levigation of technique

9. Packaging choice of container 

10. Labeling

11. Clean work area.

 

Aromatic water

·         Aromatic waters are aqueous solutions usually saturated of volatile oils or other volatile substances that are characterized by very low water solubilities.  E.g.  Chloroform.

·         Aromatic waters are used externally as perfumes (e.g. Rose water) and internally as flavoring agents (e.g. peppermint water, cinnamon water has been used as carminative and chloroform water was used in expectorant preparations).

 

Practical

1.   (a) chloroform water BP. 88
Chloroform	----------------	2.5 ml
Water FBC to	---------------	1000ml
	Send 100ml

(b) double strength chloroform water BP. 88
Chloroform	----------------	5 ml
Water FBC to	---------------	1000ml
	Send 100ml

Compounding: dissolve the chloroform in Purified water by shaking.

1.   Peppermint water
Pepper min oil	---------------	0.2 ml
Water FBC to	---------------	100ml
	Send 50ml

 

 

Compounding: dissolve the oil in purified water by shaking

1.   Spirits

·         Sprits also known as essences are alcoholic or aqueous alcoholic solutions of volatile substances. Like the aromatic water the active ingredients in the sprits may be a solid, liquid or gas. The volatile substance in the majority of case is volatile oils.

·         Some sprits are used internally for their medical value a few medically by inhalation. But a large number are used as flavoring agents.

·          

              Practical

Peppermint spirit

Ingredient	Master formula
Peppermint  oil	100ml
Ethanol (90%)	1000ml
Send 30 ml.

 

Compounding: dissolve the peppermint oil in ethanol. Add sufficient ethanol to produce the final volume. If the solution is not clear shake with previously sterilized talc and filter.

Action and uses: the spirit is an effective carminative. Also, mixed with other drugs or preparation, it may be used as a flavor.

Ingredient	Master formula
Chloroform	50ml
Ethanol (90%)	1000ml
Send 40ml

 Chloroform sprit

 

 

cmpoundiccompounding: mix the chloroform with the ethanol.

·         Uses and actions: flavoring agent and preservative

 

            

   Tinctures

·         Tinctures are alcoholic or hydro alcoholic solution of principles extracted from natural sources or of pure chemical merely dissolved in these solvent systems an example of the latter being iodine tincture.

·         Tinctures vary widely  in their method of preparation the strength of their volatile ingredients their alcoholic content and their intended use

·         Tinctures are prepared by a number of processes: maceration (process M) percolation (process p) solution and dilution.

 Iodine Tincture

Ingredient	Master formula
Iodine	25g
Potassium iodide	25g
Purified water	25mg
Ethanol (90%) to	1000ml
Send 50ml

 

Compounding: dissolve the potassium iodide and the iodide in the purified water and add sufficient ethanol (90%) to produce 1000ml.

Actions and uses: antiseptic.

   Syrups

·         Syrups are concentrated aqueous solutions of sucrose other sugars or sweetening agents to which small quantities of suitable polyhydric alcohols may be added to retard crystallization or to increase the  solubility of the other ingredients

·         Syrups usually contain aromatic or other   flavoring materials.

Practical

Simple syrup, USP
Sucrose --------- 647.4 g	Sucrose------- 850g
Purified water to ------ 1000g	Purified water to ----- 1000ml
Send 50ml

                    Methods of preparation

a.    Hot process: place the sucrose in dish, add the water and dissolve the sucrose by heating on a water bath stirring continuously. When dissolution of the sucrose is complete allow the solution formed to cool and add sufficient boiling purified water to make up for that lost by evaporation. Then strain the syrup while still warm to make up for that lost by evaporation. Then strain the syrup while still warm though a fine muslin supported in a funnel in to a bottle which is capable of nearly filling and shake the bottle occasionally until the content is quite coil.

b.    Cold process: place the sucrose in a suitable percolator, the neck of which is nearly filled with loosely packed cotton moistened after packing with a few drops of water. Pour carefully about 450ml of purified water upon the sucrose and regulate the outflow to a steady drip of percolate. Return the percolate if necessary until all the sucrose has dissolved. Then wash the inside and the cotton with sufficient purified water to bring the volume of the percolate to 100 ml and mix.

c.    Alternatively the sucrose may be dissolved more rapidly in the proper amount of water by agitation in a graduated bottle.

N.B syrup made without heat is practically colorless while syrups made with heat have pale amber color due to the levulose formed as a result of hydrolysis of sucrose.

Ferrous sulfate syrup USP

Ingredients	Master formula
Ferrous sulfate	40g
Citric acid hydrous	2.1g
Peppermint spirit	2ml
sucrose	825g
Purified water to	1000ml
Ft. syrup send 50ml
Sig. Two 5 ml

 

 

 

 

 

 

Formulation: the peppermint spirit used as the source of flavor has a persisting effect which makes the somewhat unpleasant ferruginous taste of the Fe2. Care must be taken in preparing aqueous solution of ferrous salts since Fe2+ is readily oxidized by dissolved oxygen to form Fe3+ which precipitates as basic ferric salts discoloring the solution. Ferrous sulphate is dissolve in purified water containing some sucrose which provides a reducing environment thereby in inhibiting auto- oxidation. If all of the sucrose were added the solution would be too viscous to allow perfect filtration. Citric acid is included in the formulation to prevent discoloration of the syrup i.e. a change from a green to a reddish brown tint it does this by preferentially chelating Fe3+.

Compounding: dissolve the ferrous sulfide water and filter the solution until clear filtrate and add purified water to make 1000 ml mix and filter if necessary through a placed get of cotton.

Actions and uses: Heamatnic.

 

Iodine Solution (Lugols solution)

  Ingredients                   master formula

    Iodine                                        50g

Potassium iodide                             100g

Water         up to                             1000ml

 Sent 100ml

Method:

Potassium iodide and Iodine are dissolved in small portion of purified

Water by stirring & shaking till dissolve completely.

Sufficient Water is added to make the required volume

Use: Goiter  

Compound iodine paint (mand’l paint)

Ingredient	Master formula
Potassium Iodide	25.0g
Iodine	12.5g
Alcohol 90%	40.01ml
Water	25.0ml
Peppermint Oil	4.0ml
Glycerol      to	4.0ml
Mitt. 40 ml. Sig store in cool place. Shake the bottle before use. Not to be swallowed in large quantities.

 

Compounding: put the water into a 50ml conical measure. Dissolve the potassium iodide (it dissolves very readily in water and need not be powdered). Add the iodine and stir until complete dissolved. Although iodine is only slightly soluble n water it is readily soluble in aqueous solution of iodine. In a small measure dissolve the peppermint oil in the alcohol and transfer it to the iodine solution and mix well. Make up to the volume with glycerol and mix toughly. If the iodine solution is not well.  Mixed with the glycerol the preparation is streaky.

Note: because of the high viscosity of the vehicle this preparation is best made entirely in a measure. For the same reason an excess should be prepared since it is impossible to transfer the entire contents of the measure to a bottle. A glass or a counterbalanced watch glass and a vulcanite spatula must be used for weighing the iodine

Actions and used: Antiseptic in the treatment of pharyngitis and tonstillis.

Suspension

     Suspension are disperse systems in which finely divided drug practices (called the disperse phase) are distributed thought out a vehicle (called

dispersion medium o r continues phase) in which the drug exhibits a minimum degree of solubility. It in include both powders in dry from to be place in suspension and drugs suspended in liquid vehicles.

Suspension can be classified in to coarse suspension in which the particles are large than 1um in diameter.

Major applications: suspension dosage forms can be administered orally injected parentally (intramuscularly or subcutaneously) or applied externally (topically) to the skin eye ear etc.

The physical properties of suspensions and their design depend upon the nature of the dispersed phase the dispersion medium and the pharmaceutical adjuncts/additives.The drug particles (dispersed phase) is suspension could be

o   Diffusible solids

o   In diffusible solids or

o   Poorly wettable solids

Containers and labeling

·         Suspensions are generally packed in well closed containers appropriate to the class of dispensed medicine be it mixture lotion ear drop, enema etc.

·         If the preparation is particularly viscous a wide mouthed container may be used.

·         Containers of suspensions should be of suitable size to allow shaking of the products.

·         Labels for suspensions includes:

-      Shake well before use

-      Store in cool place(not refrigerator)

-      Also expiry dates for suspensions that should be prepared recently is one month and if diluted two weeks.

Suspensions containing diffusible solids

·         Diffusible solid (also called dispersible solids) are light and easily wettable solids. They readily mix with water and on shaking diffuse evenly through the liquid for long enough for a dose to be measured.(Ensure even distribution in each dose.)

·         Examples of diffusible solids are light kaolin magnesium trisilicate light magnesium carbonate and calcium carbonate.

Practical

Pediatric kaolin mixture, BP 1988

Ingredient	Master formula
Light kaolin	200g
Amaranth solution	10ml
Benzoic acid solution	20ml
Raspberry syrup	200ml
Chloroform water (D.S)	500ml
Water to	1000ml
M.S.A. send 50ml. Sig. 1tsp t.i.d.

 

Formulation: the kaolin should preferably be sterilized to remove any contaminating soil pathogens.

Kaolin is a diffusible solid and therefore no additional suspending agent is required although the raspberry syrup increases the viscosity of the vehicle.

Benzoic acid solution and chloroform water act as preservatives. The raspberry syrup provides a flavor and amaranth solution color which is attractive to children.

Compounding: first tare the final container because if the syrup and a little of the chloroform water. Add the amaranth solution and mix well.

If the dye is added at a later stage in the preparation it will not penetrate in to the powder and white specks will be visible in the final product. Dilute the suspension until pourable and while specks will be visible in the final product. Dilute the suspension until pourable and transfer to the bottle. Although it is advisable to add volatile ingredients such as chloroform water before making up to volume with water. Add the benzoic acid solution to the bottle and make up to volume and shake thoroughly.

Storage and shelf life: unless the kaolin has been sterilized the preparation should be recently prepared.

Container: amber medicine bottle.

Advice for patients when dispensed: shake the bottle.

Maintain fluid intake in diarrhea. If the product is counter prescribed the patient should seek medical advice if the condition persists.

Actions and uses:  anti diarrhea mixture for children.

Magnesium sulfate mixture BP.88 (magnesium sulfate oral suspension)

Ingredient	Master formula	Scaled quantities
Magnesium sulfate	400 g
light magnesium carbonate	50g
Concentrated peppermint emulsion	25g
Double  strength chloroform water	300ml
Water FBC sufficient to produce	1000ml
Mitt 50ml
Sig. 10 ml t.i.d. shake the bottle before use

 

Formulation: magnesium sulfate mixture is a suspension containing 40% w/v magnesium sulfate and 5%w/v of light magnesium carbonate. Both these solids act as laxatives by preventing the normal absorption of water from the intestine with the result that the bulky fluid contents distend the bowel active reflex peristalsis excited and evacuation of the contents of the intestine occur. Active reflex peristalsis excited and evacuation of the contents of the intestine occur. Peppermint provides flavoring and act as a carminative and chloroform water acts as flavoring preservative and vehicle light magnesium carbonate is a diffusible solid and no extra thickening agent is required.

Compounding:  first tare the final container and select a mortar of sufficient size to allow for adequate mixing of the product. Mix the magnesium sulfate and light magnesium carbonate in the mortar. This method is to be preferred to making a separate solution of the magnesium sulfated which is time consuming. Add enough vehicle to make a smooth paste and dilute with the vehicle unit sufficiently pour able to transfer to the bottle. The volatile peppermint emulsion should be added to the bottle before making up to final volume.

The mixture may also be prepared from a pre packed mix of the two powder ingredients with the addition of the appropriate amount of peppermint emulsion and chloroform water.

Storage and shelf life: the mixture should be recently prepared.

Container: amber medicine bottle.

Advice for patients when dispends: shake the bottle

Actions and uses:  as laxative.

B. Suspensions containing in diffusible solids

In diffusible solids will not remain evenly distributed in a vehicle long enough to ensure uniformity of dose. Examples include chalk, zinc oxide, calamine aspirin and phenobarbitone.

The simplest way of correcting this problem is to increase the viscosity of the formation of aggregates that settle rapids

The thickening agents used to stabilize suspensions is substances that spontaneously from colloidal dispersions in aqueous media because of their affinity to water. There are three major groups of thickening agents:

1.   Polysaccharides include acacia, tragacnath, methylcellulose, sodium alginate, microcrystalline cellulose sodium carboxymethyl cellulose starch etc.

2.   Inorganic agents include bentonite veegum hectorite aluminium hydroxide etc

3.   Synthetic agents include carboxyvinyl polymer(carbomer) colloidal silicon dioxide etc.

 

 

Calamine Lotion B.P.

              Ingredients               master formula

Calamine                                15g        

Zinc Oxide                              5g

Bentonite                               3g

Sodium Citrate                     0.5g

Liquid phenol                        0.5g

Glycerin                                 5ml

Purified Water   to               100ml

Procedure:

1)      Dissolve Sodium Citrate in 35ml Purified Water

2)      Weigh Calamine, Zinc Oxide and Bentonite & triturate it with Sodium. Citrate solution.

3)      Add Liquid phenol, the Glycerin and sufficient quantity of water to make up the required volume.

                4)  Write Label

  Use: Astringent & protective.

Compounding: first tare the final container and select a large mortar. Mix the dry powers in the mortar until evenly dispersed. It is important that the bentonite is well distributed in the in diffusible powders. Use the calcium hydroxide solution to make a smooth paste and to dilute the formed paste for transfer to the bottle. Add the glycerol and liquid phenol to the bottle and make up to final volume    with the vehicle.

Strong and shelf life: the preparation is stable cool storage is advised because of the volatile preservative.

Advice for patients when dispensed: shake the bottle for external use only. The lotion is applied to the skin as required and allowed to dry.  Action and uses: cooling lotion useful for treating mild sunburn.

 

 

 

                                               OINTEMENTS

Ointments are semisolid preparations intended for external application to the skin or mucous membranes.

Ointments may be medicated or non- medicated the later type being commonly referred to as ointment bases and are used as such for their emollient or lubricant effect of used as vehicles in preparation of medicated ointments.

·         Hydrocarbon bases

·         Absorption bases

·         Water-miscible bases

·         Water soluble bases

 

Preparation

 Ointments are not applied primary to irritated areas it is an on broken wound rule that these preparations must contain granular or gritty particles, which might cause further irritation regardless of the condition of the skin. Ointments must be smooth and free from granular or gritty particles.

Three types of equipment are available for the preparation of ointments

1.      Ointment slab and spatula

2.      Mortar and pestle

3.      Ointment fill

Two techniques are used mixing ointments

Mixing by fusion

On a small scale fusion is usually carried out in an evaporating basin a water bath

Fusion is necessary when waxes, hard paraffin, fatty alcohols, fatty acids or any hard wax- like material is included in the formula.

Fusion is used also when a medicament is soluble in the melted base

Mixing by trituration

This method is applicable when the medicament is a solid insoluble in the bases or liquid present in small amount

Trituration may become out with an ointment tile and spatula or using a mortar and pestle

Packaging

Ointments are dispensed in either ointment or collapsible tube. However ointments prepared extemporaneously are usually packed in ointment jar.

Procedure will be demonstrand

The ointment should be packed and the top surface should be smoothed neatly.

 

 

Ointments jars should be closed tightly when not in use particularly if the ointment consisting water to prevent loss though operation.

Storage

Ointments should be stored in a cool place to prevent softening and eventually liquefiable in the base

Insoluble medicament may settle to the bottom of the container if the ointment is permit to liquefy.

Excessive heat or cold may cause an emulsion base to separate into two phases.

a.      Simple ointment BP

Ingredients                             master Formula                     Reduced Formula

Wool fat                                              50g

Hard paraffin                                      30g

Cetostearyl alcohol                             50g

Yellow or white soft paraffin             850g

            Send 25g

Formulation: simple ointment is an absorption base prepared by fusion . yellow or white soft paraffin is chosen according to the color of the finished product. In this case there is no dark colored ingredient to be added. White soft paraffin should be used.

Compounding: grate the hard paraffin and weigh out the ingredient for the base. place to melt an evaporating dish on a water –bath. stir gently to aid melting and to mix the ingredients. When homogenous, remove from the beat and continue to stri gently until cold .

NB. Weigh the wool fat and the soft paraffin using waxed papers to allow full recovery of  the materials.

Storage: store in cool places

Action and use: ointment base emollient

 

a.      Sulfur ointment BP

Ingredients                                         master formula                                  reduced formula

Precipitated sulphur, finely sifted       100g

Simple ointment                                  900g

                         Send 25 g

Formulation: the BP directs that the simple ointment be prepared with white soft paraffin ointment is adequate to ensure that 22.5g will be available (to compensate for the manipulative   losses).

Compounding: weigh out the amount of precipitate sulphur required and place it on the center ointment tile, weigh the required amount of simple ointment (using a piece of waxed paper) and place it on side of the tile Take a portion of the base (about two to three times the weight of the powder) and levigate it with the sulphur until there is no sign of any gritty particles (this can checked for by spreading a thin layer on the tile). Gradually incorporate the reaming base in geometrically and continue levigation until uniformly mixed. Finally, collect the ointment to gather the center of the tile using the spatula and pack into an ointment jar.

Storage and shelf life : store in a cool place .

An expire date of 4 weeks is appropriate.

 For External use only.

Container: wide – mounted amber jar with a grease proof paper disc

Advice for patient when dispensed: the skin should be cleansed prior to application and  t ointment applied sparingly to the affected area .

Action and uses: mild antiseptic used in the treatment of acne and scabies.

 

a.      Whitfield’s Ointment

Ingredients                                         master formula                                  reduced formula

Benzoic acid, in fine powder              60 g

Salicylic Acid, in fine powder            30g

Emulsifying ointment                                     910 g

                     Send 20gm

Compounding: sift the medicament through separate 180µm sieves. Note that salicylic acid very irritant to the respiratory tract and precautions should be taking to avoid inhalation. Weigh the powders after sifting and mix them. Then place them on an ointment tile and levigate with two or three times their weight of the base until homogenous. Gradually incorporate the reaming base.

Storage shelf life: store in a cool place.

Container: wide – mouthed amber jar with a greaseproof paper disc.

Advice for patients when dispensed: the ointment should be applied sparingly to the affected area. Is should not be applied to the broken or inflamed skin.                                               Actions and uses: topical anti fungal preparation

                                   Pastes

Pastes are ointment-like preparations intended for external application .most paste differ from ointments in containing large amounts of finely powdered solids, thus they are usually stiffer than ointments, less greasy and more absorptive.

They are applied generously, either with a spatula or spread on lint or other dressing and are not removed for long periods.

Compounding and packaging

For all practical purposes, pastes are prepared in the same manner as ointments

Pastes are generally packed in glass ointment jars.  They are often too viscous for easy extrusion from tubes.

   Zinc oxide paste. U.S.P

Ingredients                                         master formula                                  reduced formula

Zinc oxide, finely sifted                                 250g

Starch, finely sifted                                        250g

White petrolatum                                            500g

            Send 20g

Compounding: melt the base with a minimum of heat and sift the powders through separate 180 µm sieves. Mix the required weight of powders in a warm mortar. Triturate with a little melted base until smooth, gradually adding the rest of the base and until cooled.

NB. The paste is much easier to manipulate in a warm mortar

Storage: store in a cool place

Container: wide – mouthed amber jar with grease proof paper disc.

Advice for patient when dispensed: the paste should be spread thickly on white lint and applied to the affected area.

Actions and uses: absorbent, protectant and mild astringent used for variety of dermatological conditions including eczema and psoriasis either alone or with additional medicaments.