Pharmaceutical Dosage Form (1) By Dr. Fathy Ibrahim Abd Allah Assistant Professor of Pharmaceutics
Pharmaceutical dosage forms ďƒ˜ Pharmaceutical
dosage forms are drug delivery systems: they are means of getting drugs into the body in a safe, effective and reproducible manner. ďƒ˜ Drug
substance are seldom administered alone, but rather as part of a formulation in combination with one or more non-medical agents (pharmaceutical ingredients) to give a practical dosage form : in other words the drugs must be formulated.
ďƒ˜In addition to facilitate administration of the drug, the dosage forms are needed for;
1- The protection of a drug substance from destructive influence of atmospheric Oxygen or humidity (e.g. coated tablets and sealed ampoules. 2- Protection of the drug from gastric acid after oral administration (e.g. enteric coated tablets). 3- To mask the bitter, salty, or offensive taste or odour (capsules, flavoured syrup, coated tablets).
4- To provide clear liquid dosage forms of substance (syrup, solution).
5- To provide time-controlled drug action (e.g., various controlled release tablet, capsule and suspension). 6- To provide optimal drug action from topical administration sites (ointment, creams, ophthalmic, transdermal patches). ' 7- To provide the insertion of a drug into one of the body orifices (rectal or vaginal suppositories). 8- For the placement of drugs directly into the blood stream or into body tissues.
Definition: homogenous one phase system consisting of two or more components.
The solvent: the phase in which the dispersion occurs. The solute: is that component that is dispersed as small molecules or ions in the solvent.
Another Def.: homogenous mixture that is prepared by dissolving a solid, liquid, or gas in another liquid.
Advantages of Solutions
Suitable for those who have difficulty in swallowing as young children & elderly people.
Solutions gives faster action than tablets & capsules.
Solutions gives more uniform dose than suspension.
Reduce the gastric irritant action caused by some drugs since it is immediately diluted by gastric content
Disadvantages of Solution
Inconvenient to transport and store.
Soln. is less stable than solid dosage forms.
Provide suitable media for the growth of M.O.
Unpleasant taste or odor which are difficult to mask.
Soln. needs accurate spoon to measure the dose due to it may be in multiple dosage form.
Preservatives ďƒ˜ It
is necessary to add a preservative to the product to decrease the probability of product contamination ďƒ˜ The major criteria that should be considered in selecting a preservative are: 1- Effective against wide range of M.O 2- Stable for the shelf life of the formulation. 3- Non toxic 4- Non sensitizing 5- Relatively free of taste and odour.
Examples of preservatives commonly used in solution ďƒ˜A
large number of compounds can be used as a preservatives, they are classified according to their molecular structure but only a few will be mentioned: 1- Alcohols .Ethanol------- solvent and preservative .Propylene glycol--- preservative in the oral and topical preparations . Chlorobutanol and phenyl ethyl alcohol
2- Acids . Benzoic acid: only the non ionized form is effective, and therefore its use is restricted to preparations with a pH below 4.5. . Sorbic acid: also, the preservative action is due to the non ionized form and so, it is effective only in the acidic media. Both acids characterized by low solubility in water and only a small concentration is required.
3- Esters (Parabens) . Parabens are esters of p-hydroxybenzoic acid and include the methyl, ethyl, Propyl and butyl derivatives. . These compounds are widely used in pharmaceutical products and are effective and stable over a pH range of 4 to 8. . Frequently two esters are used in combination in the same preparation to achieve a higher total concentration and the mixture will be effective against a wide range of M.O.
4- Quaternary Ammonium compounds .This class of compounds has an optimum activity over a pH range of 4 to 10 and are stable in room temperature. . Because of the cationic nature of this class, it is incompatible with many anionic compounds. . It is used mainly in preparations for external use and those solutions that comes in contact with mucous membranes. . Benzalkonium chloride is the most famous member in this class.
Methods of Preparation 1. Simple Solution ď Ź
Simply by dissolving the solute in most of the solvent, mixing until dissolved, then adding the rest of the solvent. The solvent may contain other ingredients that stabilize or solubilize the A.C.
e.g. Calcium Hydroxide Solution (lime water). R/ Ca (OH)2 3g water 1000 ml
N.B. the solution must kept in closed container to avoid interaction with CO2 of the atmosphere.
Uses: it is used as a vehicle in topical preparations for its soothing effect.
solvent may contain other ingredients which stabilize or solubilize the solute. e.g.
KI is used to solubilize Iodine in water Strong Iodine Solution (Lugal`s Solution) R/ Iodine 50 g Pot. Iodide 100 g water to 1000 ml N.B. Solubility of iodine (1: 2950). Role of KI: it increases the solubility of I2 in water due to the formation of more soluble polyiodide. Uses: it is used in treatment of goiter (enlargement of thyroid gland due to hypothyroidism).
2. Solution by Chemical Reaction ďƒ˜ Here
soln. is prepared by reacting two or more solutes with each other in a suitable solvent.
e.g. Aluminum Subacetate Solution USP R/ Aluminum sulfate 145 g Calcium carbonate 70 g Acetic acid 160 ml Water to 1000 ml the mixture is set aside for 24 hrs., the product is filtered, and adjust the volume to 1000 ml with water. Uses: it is used as astringent in ear drops.
3. Solution by Extraction Used This
for plant & animal products.
type of preparation are more often called extractives.
Pharmaceutical classification of solutions according to vehicles A) B)
A) B) C)
Non Aqueous Aqueous . viscous or sweet . non viscous, non sweet OR Aqueous solution Non Aqueous solution Sweet or viscous solution
Aqueous Solution: . This class limit the solvent to water and exclude those preparation that are non aqueous or sweet and/or viscous in characters. . It include that pharmaceutical forms that are designated as water, aromatic water, aqueous acids, douches, enemas, gargles, mouth washes, juices, nasal solutions, otic solutions, and irrigation solutions
1) Water ďƒ˜
It is a very dilute solution of calcium, magnesium, iron, sodium, and potassium, having bicarbonate, sulfate, and chloride as a counter ions.
Hard water are those that contain high level of calcium and magnesium cations.
a) Potable water (tap water) Is the water that is fit to drink, the process of preparation involves the removal of insoluble matter through coagulation, settling, and filtrations, then destruction of pathogenic M.O. by chlorination, finally improving the palatability through aeration and filtration through charcoal. N.B: Hard water cause the ppt of soap and prevent its lathering and form scale in boilers and water pipes. Softening is achieved by chemical treatment through adding lime (CaO) or ammonia to partially remove the dissolved salts as ppt of carbonates (Ca and Mg) and hydroxides (iron).
b) Purified water: . Prepared by distillation, ion exchange, reverse osmosis, or other methods in which we aim in removing the dissolved solids. . Distillation is not effective in the removal of week electrolytes and non electrolytes if they are volatile. . Purified water may be rendered sterile and pyrogen free by repeated distillation in a still with baffle system.
Ion exchange (deionization, demineralization):
. The resins are mainly of two types 1- Acid or cation exchanger Help the replacement of cations with hydrogen ion CaSO4 + RH2 ----------- CaR + H2SO4 Ca(HCO3)2 + RH2 ------ CaR + 2H2CO3 2- Base or anion exchanger Permit the removal of anion H2SO4 + 2 AOH --------- A2SO4 + 2 H2O Charging and rewashing of columns is carried out by acids for the cation and resins and bases for the anion resins.
Osmosis involve the passage of water from a dilute solution across a semi permeable membrane to a concentrated solution.
While reverse osmosis involve applying a pressure greater than the osmotic pressure to allow passage in the reverse direction. Cellulose acetate is an example of the semi permeable membrane for purifying water by reverse osmosis. Organic molecule are rejected on the basis of sieve mechanism related to their size and shape.
The pore sizes of the membrane used for reverse osmosis is between 0.5 and 10 nm which allow the rejection of viruses and bacteria larger than 10 nm unless imperfections are present. Some times we use membranes made of polyamide materials or a series of two membranes to enhance the process.
c) Water for injection It is a purified water prepared by distillation or by reverse osmosis which is free from pyrogen, used as a solvent in parenteral solutions. Pyrogen (fever produce): is a lipopolysaccharide toxins released from Gm â€“ve bacteria that can elevate the body temperature if reached the blood.
Pyrogen characterized by: water soluble, non volatile, thermostable, and not affected by the common bactericides.
d) Sterile water for injection water for injection sterilized by autoclaving in sealed container immediately after collection. e) Water for injection free from dissolved gases This is prepared by boiling freshly prepared pyrogen free water for 10 min to dispel dissolved gas as air or CO2, then immediately sealed into its final container. N.B: This dissolved gases as CO2, may cause change in the (pH) or chemical interaction with the A.C. f) Bacteriostatic water for injection Sterile water for injection containing one or more suitable antimicrobial agent. g) Sterile water for irrigation Which is a sterile water without antimicrobial agent or other added substances in a suitable package.
2) Aromatic water
Def. : more or less saturated clear or almost clear aqueous soln. of volatile oils or other volatile substance. Uses: Provide pleasantly flavored vehicles for water soluble drugs.
Preparation: 1. Distillation. 2. Solution. 3. Alternate solution method. 4. Dilution method.
Requirements of good aromatic water The aromatic waters should have: 1. An odor and taste similar to the sub. From which they are prepared. 2. Clear and free from fibers, particles & sediment. 3. Freshly prepared (few weeks). 4. Free from foreign odor.
1. Distillation ďƒ˜ Consist
of placing the part of plant or drug containing the odor in a suitable still with sufficient purified water and then distilling most of the water. The product which is the aqueous phase may require clarification.
flower and strong rose water is an example to aromatic water prepared by this method.
2. Solution Method ďƒ˜
Involve Shaking the volatile substance with purified water for 15 minutes. The mixture is set aside for 12 hours, then filtered through wetted filter paper.
e.g. chloroform water, peppermint water. N.B. Large excess of solute is used in order to obtain a saturated solution. The filter paper must be wet to prevent the passage of excess oil and to eliminate the absorption of the dissolved aromatic substance.
3. Alternate solution method The volatile material is mixed with 15 gm purified talc, the mixture is agitated with a liter of purified water for 10 minutes before filtration. N.B: The talc or other inert material function both a filter aid and a distribution agent. Unlike the solution method, no clarification and the time saving factors present an important advantages.
4. Dilution method
Suitable for concentrates which are designed to be diluted with an appropriate volume of water when need.
An alcoholic solution of the essential oil is mixed with water and talc, agitation several hrs, filtration to get the concentrated alcoholic solution.
The aromatic water is prepared by diluting the concentrate with 39 times its volume of water.
Peppermint, dill, cinnamon, and caraway are examples.
Disadvantages of Aromatic Water 1- Incompatible with soluble salts due to salting out. 2- Deteriorate (become cloudy) with time & so should be freshly prepared. N.B. Deterioration may be due to volatilization, decomposition or mould growth. 3- They are sensitive to light & excessive heat, and so must be kept in cool dark place.
3) Aqueous acids
In organic acids and certain organic acids although of minor importance as therapeutic agents, are of great importance in chemical and pharmaceutical manufacturing.
Acetic acid, hydrochloric acid, and nitric acid are the widely used examples.
Diluted HCl has been used in the treatment of achlorhydria, however it may irritate the mucus membrane of the month and attach the enamel of the teeth.
Def.: its an aqueous soln. directed into one of the body cavity.
Uses: Cleansing or antiseptic agent.
e.g. Vaginal douche, pharyngeal douche, and eye douche.
They are usually dispensed in the form of a powder, tablet or ready made solution which is to be diluted with warm water.
Vaginal douches are the common type of douches, which are used for (cleansing the vagina and for hygienic purposes), mainly supplied as a liquid concentrates or powder.
Vaginal douches usually contain ingredients that function as (antimicrobial, anesthetic or antipruritics, astringent, surface active agents, and chemical that alter the pH).
5. Enemas Def.:
Aqueous rectal injections employed to evacuate the bowel (evacuation enema), influence the general system by absorption , or to affect a local disease (retention enema).
enema may possess anthelmintic, nutritive, sedative or stimulating properties .
may contain radiopaque substance for graphic examination of the lower bowel.
enemas should not be used in larger quantities than 150 ml for an adults.
= small volume enema
e.g. . Monosodium phosphate and disodium phosphate (Enemax) as evacuation enema. Sulfasalazine (Pentasa enema) rectal enema for treatment of ulcerative colitis. Diazepam (Stesolid) rectal enema for treatment of febrile convulsions. Starch enema may be used itself or as a vehicle for other forms of medication.
Def.: aqueous soln. usually antibiotics and/or anesthetics.
Uses: treatment of pharynx & nasopharynx by forcing air from the lungs through the gargle that is held in the throat; then the gargle is expectorated.
Many gargles should be diluted with warm water before use.
Many of the mouth washes can be considered as gargles either as it is, or to be diluted with water.
7. Mouthwashes ďƒ˜
Def.: aqueous soln. often in concentrated form containing one or more active ingredients & excipients.
Mouthwashes Used for two purposes
Cosmetic To reduce bad breath
Therapeutic Mouthwashes ďƒ˜
They are formulated to reduce plaque, gingivitis, dental caries, ulcerative lesions of the mouth and stomatitis.
Mouthwashes containing antihistamines, nystatin, hydrocortisone & tetracycline have been formulated to treat stomatitis. ďƒ˜ Mouth washes generally contain four ingredients: 1- Alcohol: used as preservative and for its solubilizing action for the flavor, some alcohols as glycerin and sorbitol may used as humectants. 2- Surfactants: aid in the solubilizing of flavor and in the removal of debris by its foaming action. 3- Flavor: to overcome the disagreeable tastes. e.g: peppermint, cinnamon, menthol, and methyl salicylate. 4- Coloring agent: to gives good appearance and differentiate between products.
Prepared from fresh ripe fruit & is aqueous in character.
Uses: making syrups which are then used as a vehicle.
It must be preserved with benzoic acid and allowed to stand at room temperature for several days until pectin is destroyed by the naturally present enzymes.
Cherry juice used as flavored vehicle.
Artificial flavors are now used instead of juice as they are more stable & easier to incorporate in the final product although they lack the flavor of the natural juices.
9. Nasal Solutions ďƒ˜
Def.: soln. usually aqueous to be administered to the nasal passage in the form of drops or sprays. Aim of administration: 1.
Local sympathomimetic effect. (Naphazoline, ephedrine), to reduce nasal congestion. Systemic action. (Desmopressin), in treatment of diabetes insipidus due to a deficiency in antidiuretic hormone, in the treatment of nocturnal enuresis, and (calcitonin) in treatment of osteoporosis. They are usually isotonic, slightly buffered and contain antimicrobial agent such as Ephedrine nasal drops: Ephedrine HCl 0.5 g Chlorobutanol 0.5 g NaCl 0.5 g water to 100 ml
10. Otic Solution
Aqueous solution for topical administration to ear. The main classes of drugs used: Analgesics as benzocaine, cinchocaine, and choline which are used also for surface anesthesia for the temporary local relief of pain. Antibiotics as neomycin, chloramphenicol, ciprofloxacin, cliquinol. Anti inflammatory agents as cortisone, flumetasone, dexamethasone. Viscous liquids such as glycerin or propylene glycol are used alone or with surfactant to aid in the removal of cerumen (ear wax).
1. 2. 3.
Sodium Bicarbonate Ear-Drops:
11) Irrigation Solutions Used
to wash or bathe surgical incision, wounds, or body tissue.
must be sterile, free from solids and bacterial endotoxins.
are prepared from the water of injection and packed in a single use or multiple use suitable plastic containers.
II) Sweet or other viscid aqueous solutions ďƒ˜ Solutions
that are sweet or viscous make use of the sugars, polyols, or polysaccharides (gums) for the preparation of this class.
Honeys, Mucilage, and Jellies are examples of this class.
Def.: it’s a nearly saturated aqueous solution of sugar such as sucrose in water, with or without medicinal or flavoring ingredients.
Syrups may be: Simple ‘sugar only’, flavored ‘aromatic substance’, or medicated ‘contain drug’.
Syrups are used as a sweetening agent or a vehicle.
Glycerin or sorbitol (polyols) is added to: Retard crystallization of sucrose. Increase the solubility of added ingredients.
Alcohol is added to: Act as a preservative. (Antimicrobial agent) Solvent for flavors.
It is important that the concentration of sucrose approach but not quite reach the saturated point. In dil. Solution---- sucrose provides an excellent nutrient for microorganisms. In conc. Solution---retard the growth of m.o., however, a saturated solution may lead to crystallization of a part of the sucrose under condition of changing temperature.
When heat is used in the preparation of syrup, inversion of a slight portion of sucrose into dextrose and fructose takes place, this inversion is increased by the presence of acids.
Fructose (levulose) formed during the inversion is sweeter than sucrose and is responsible for the dark color of the syrup.
Preparation of Syrups
Soln. with Heat
Agitation without Heat
Addtn. of ' Medicating liquid to the Syrup
1- Soln. with Heat 1. 2. ďƒ˜
ďƒ˜ 1. 2.
Sucrose is added to the aqueous soln. Heated until the soln. is affected, strained, then complete to the desired volume. It is the method of choice for the preparation of syrup when the active constituents is neither volatile nor affected by heat, and to prepare syrup rapidly. Take care excessive heating may cause inversion of sucrose which leads to: Light amber color due to (caramelization). Increased tendency to fermentation.
2- Agitation without Heat This
method is used when heat may affect the active constituents. The aqueous soln. of sucrose is placed in a bottle of about twice the size required for the syrup. Shake the bottle which must be well stopperred to avoid contamination & loss during the process. E.g. Codeine phosphate syrup
3- Addition of a medicating liquid to the syrup ďƒ˜
Medicated liquid in which alcohol is often an ingredient of this liquid represent a problem during the preparation of such syrups since it usually develop a precipitates.
Alcohol is used to dissolve resinous and oil substances in this liquids (e.g. tincture or fluid extract liquid ).
Preparation: Mixing this medicated liquid with water then allow the mixture to stand till complete separation of insoluble constituents. Filter then dissolve sucrose in the filtrate.
4- Percolation In this procedure, purified water or an aqueous
solution is permitted to pass slowly through a bed of crystalline sucrose packed in a percolator, thus dissolving it and forming syrup. A piece of cotton is placed in the neck of the percolator to prevent the passage of un-dissolved sucrose.
To be successful in this process ( Precautions):
1. The percolator should be cylindrical with a short conical base. 2- A coarse granular sucrose must be used to avoid formation of compact mass through which the liquid can not pass.
3- The cotton must not be pressed too tight (slow flow) or too loose (fast flow). Syrup
Method of preparation
Soln. with heat
Non-volatile or thermostable substances
Agitation without heat
Volatile & thermolabile substances
Additn. of medicating liquid
Wide range of substances
Some official syrups 1.
In E.P. Sucrose 667 gm Water to 1000 gm
In U.S.P. & B.P. 850 g 85%w/v to 1000 ml
Description: a clear heavy viscous liquid. Storage: in tight containers, at a temp. not above 25C. Uses: as sweet vehicle, sweetening agent, excipient in pills, and as the basis for many flavored and medicated syrups. Notes: Sucrose is a disaccharide which undergoes hydrolysis to give dextrose (glucose), and levulose (fructose). As a result of this hydrolysis: Solutions of invert sugar are more subject to fermentation. Solution of invert sugar is sweeter. The fructose formed is also responsible for the brown discoloration. This change is called caramelization, it also takes place in syrups containing strong acids.
Preservation of syrups
Nearly saturated solutions of sucrose, if properly stored, do not need a preservative. As these solutions do not contain free water so they are anhydrous medium with respect to growth of microorganisms. otherwise a preservative must be added, if the concentration of sucrose is less than 85% w/v, as glycerin, parabens, sodium benzoate & benzoic acid. The amount of preservative is proportional to the amount of the free water. In some syrups alcohol is present in small amounts. It serves as a solvent for certain ingredients and as a preservative, as that alcohol evaporates on the surface of syrup and thus prevents the growth of surface molds.
Artificial syrups (non-nutritive) are needed to be administered to persons suffering from diabetes mellitus. Glycerin is the first substitute for syrup, and it is characterized by its sweet taste and it is viscous liquid, but its disadvantage is that it is a glycogenic sub. (i.e. converted to glucose in the body). Artificial simple syrup: sodium CMC comp. sod. Cyclamate solution cyclamate sodium saccharin sodium
1.5% 2.8% which consists of: 6% 0.6%
Saccharin sodium is 300 to 550 times as sweet as sucrose, but it is bitter taste. Cyclamate sodium is 30 to 40 times as sweet as sucrose, and has less bitter taste. Aspartame is the widely used artificial sugar now a days.
Honeys are thick liquid preparations used as vehicle instead of
BPC lists one preparations containing honey.
Squill Oxymel; Contains squill, water, acetic acid and honey and is prepared by a maceration process.
N.B: They are unimportant as a class of preparation today.
3.Mucilage Def. Thick viscid, adhesive liquid produced by dispersing gum in water or extracting mucilaginous substances from vegetable substances.
Mucilage are liable to decomposition & should be used immediately unless a preservative is added.
Acacia mucilage is prepared as (35% in water) & Tracaganth mucilage (6% in water) both contain benzoic acid as preservative.
Mucilage are used as suspending agents.
Precipitated by alcohol Viscosity reduced by: acid, alkali, NaCl and if it is heated. It shows max. viscosity at pH 5.
Soluble in dilute alcohol solution Hydrolyzed by dilute acids Its viscosity is low but is maintained over a wide pH range.
Synthetic agents as polyvinyl alcohol, methylcellulose, carboxymethylcellulose,â€Ś.are used as mucilage substitutes .
Advantages of synthetic gums: 1. Non glycogentic & so can be used in preparations for diabetic persons. 2. They are stable at different pH values. 3. Continuously available. 4. Do not contain oxidizing enzymes.
Jellies are class of gels prepared by dispersing a polymeric matrix
substance in a high portion of liquid, usually water.
They are similar to mucilage, in that they may be prepared from acacia, gelatin and carboxymethylcellulose and similar substances.
But differ from mucilage in having a jelly-like consistency.
Uses: Jellies are used as lubricants for surgical gloves, catheters, rectal thermometers and ultra-sonic devices.
Therapeutically, vaginal jellies which contain contraceptive substances are also available.
Jellies are prone to microbial contamination and so, preservatives like Parabens may be included.
III. Non Aqueous Soln. Classified into four groups: Ethereal solutions e.g. (Collodion). Alcoholic or hydro-alcoholic e.g. (Elixirs, Spirits). Glycerol e.g. (glycerol of starch, glycerol of borax, glycerol of phenol, glycerol of boric acid, and glycerol of tannic acid). Oleoginous: e.g., Inhalations (inhaler, nasal spray) , Liniments (calamine), OLEO Vitamins (seven seas), and extractive.
1. Collodions Def.:
Liquid preparation containing pyroxyline ( a nitro cellulose) in a mixture of ethyl ether & ethanol. When ether and ethanol are evaporated, they leave a protective film of pyroxylin on the surface. It is made flexible by the addition of castor oil 3%. Collodion and flexible collodion are water repellent protective for minor cuts and scratches. e.g. Salicylic Acid colloidon USP contain 10% w/v salicylic acid, used as keratolytic agent in the treatment of corns and warts.
Def.: Clear, pleasantly flavored, sweetened hydro-alcoholic liquids intended for oral use. Uses: Flavors & vehicles for drugs. They are differ from syrups by presence of sugar and alcohol in the finished product. The alcoholic content in Elixir varies greatly (4-40%). Beside ethanol & water, (glycerin, sorbitol, propylene glycol, flavoring agents, preservatives & syrups) are added in the final preparation. Medicated elixirs as chlorpheniramine maleate elixir USP used as antihistaminic and pepsin elixir used as digestive.
Incompatibilities in Elixirs Alcohol present in elixirs precipitates tragacanth, acacia, agar & inorganic salts from aqueous solution. 2. On addition of water to alcoholic soln. partial precipitation may occur due to dilution of alcohol. 1.
1. 2. 3. 4.
Def.: are stable solution or mixtures of medicinal substance in glycerin. Geyserites containing not less than 50% by weight of glycerin. Because of the high % of glycerin they are viscous, hygroscopic and heavy preparation. Being hygroscopic, they should be stored and dispensed in tightly closed containers. Advantages of glycerin: Valuable solvent and vehicle. Its good taste (sweet). As a preservative and does not become rancid. miscible with water, so can be diluted from its stock solution.
Some Official Glycerites 1. Glycerol of starch: R/
Starch Benzoic acid Dist. Water Glycerin ad
10 g 0.2 g 20 ml 100 ml
Procedure: 1. Rub starch and benzoic acid with dist. Water -- smooth mixture. 2. Add the mix to the glycerin previously heated to about 140 ºC, and mix well. 3. Heat at temp not exceed 140 ºC with stirring--- translucent jelly. Uses: 1. Emollient and demulcent or as a vehicle for local preparations. 2. As excipient in pills and as a greaseless base for ointments. Comments: 1. Heating glycerin before addition of starch suspension is to avoid evaporation of water. 2. Heating not to lower than 140 ºC --- not sufficient to burst starch grains for gelatinization. 3. Heating not to higher than 140 ºC --- darkened product from carbonization. an irritant vapors of acroline.
2. Glycerol of Boric Acid It contains 31% of boric acid in glycerin. Procedure: 1. Heat glycerin on a sand-bath to 140 ÂşC. 2. Add finely pd. Boric acid with stirring and heat until dissolved. 3. Continue heating with stirring then add warmed glycerin to adjust the required weight. Comments: 1. When glycerin and boric acid are heated together, 3 molecules of water are given off and boroglycerin is formed. 2. Heating above 140 ďƒ decomposition of glycerin producing an irritant vapors of acroline. 3. Three molecules of water must be removed from the product to avoid pptn. Of boric acid again. 4. The product must be stored in a dry containers. Uses: antibacterial and when diluted with glycerin can be used for its antiseptic effect as a throat paint.
3. Glycerol of tannic acid It contains 15% of tannic acid in glycerin. Procedure: 1. Rub tannic acid with about Â˝ amount of the glycerin-ďƒ smooth mixture is produced. 2. Add the remainder of glycerin and mix well. 3. Warm gently until solution is affected. Uses: 1. It is used for its astringent action in treatment of spongy gums and sore throat. 2. When diluted with water can be used in stomatitis, pharyngitis, tonsillitis, and trachoma.
4. Glycerol of Phenol It contains 10% of phenol in glycerin. It is used for germicidal and antiseptic action as ear drops.
4. Inhalations & Inhalants ďƒ˜ Inhalations:
Drugs, solution, or suspension of one or more drug substance administered by nasal or oral respiratory route for local or systemic effect. Uses: Bronchial & Nasal congestion. Inhalations gives their effect through the use of special devices such as: ďƒ˜ 1- Nebulizers: are suitable for the administration of inhalation solutions by providing the drug as a droplets of fine and uniform size so that the mist reaches the bronchioles.
2- Metered dose inhalers (MIDs): suspension or solution in liquefied gas (propellant) with or without cosolvent, intended to deliver the drug to the respiratory tract.
3- Vaporizer: a device used with a number of commercially available preparations that can supply the drug as a vapor by the use of boiling water.
Particle size is of major importance in the administration of these preparations (0.5-7mm).
Inhaler (Inhalants): A special class of inhalations consists of a drugs present at high vapor pressure in a special device (inhaler) that can be carried by an air current into the nasal passage where they exert their effect. E.g. Amyl nitrate inhalant ( for angina pain).
Def.: Soln. or mixtures of various substances in oil, alcoholic solution of soaps, or emulsions. They are intended for external application and should be labeled. Applied with friction and rubbing of the affected skin. The oil or soap provide ease of application and massage. Alcoholic type: are used for rubefaciant, counterirritant, mildly astringent, & penetrating effects.
Oily liniments: are milder in action as they can't penetrate the skin easily & so they are used mainly in massage. Liniments should not be applied to injured or broken skin.
6. OLEO Vitamins Def.:
Fish liver oils diluted with edible vegetable oil or soln. of the indicated vitamins (usually vitamin A & D)
D: It can be present as ergocalciferol or cholecalciferol obtained by the activation of ergosterol or 7-dehdrocholesterol or from natural sources. Vitamin
A: synthetic Vit. A or its concentrate. It should be stored in small, tight containers, & protected from light.
7. Spirits (Essences)
Def.: Alcoholic or hydro alcoholic solutions of volatile substances. Alcohol concentration usually over 60%. Uses: Internally for their medicinal values, several are used by inhalation, while a large number are used as flavoring agents.
They must be stored in tight, light resistant containers, and in a cool place to prevent evaporation of alcohol or the active principle.
Method of preparation: Simple solution method or Solution with maceration The solution with maceration involve placing the leaves (coarse powder) for 1 hr in water to remove tannins and other water soluble substances. The leaves then squeezed and while moist they added to alcohol. The leaves are macerated with agitation in alcohol for 6 hrs to extract the chlorophyll. After filtering the mixture, the volatile oil is dissolved in the filterate.
8. Toothache Drops ďƒ˜
Def. Preparations used for temporary relief of toothache by application of a small cotton saturated with product into the tooth cavity.
Example: Clove oil which contain a high concentration of eugenol which safe and effective for tooth pain.
These preparations no longer are recognized due to the advanced technology in the dental services however, in some area with inadequate dental services, pharmacist may need it.