312 PHT

1. 312 PHT Nahla S. Barakat, Ph.D King Saud University Dept. of Pharmaceutics Second Term 1430-2009 PHT 312 1

2. Solution is a homogenous mixture composed of two or more substances. In such a mixture, a solute is dissolved in another substance, known as a solvent. A common example is a solid, such as salt or sugar, dissolved in water, a liquid. Gases may dissolve in liquids, for example, carbon dioxide or oxygen in water. Liquids may dissolve in other liquids. Gases can combine with other gases to form mixtures, rather than solutions. PHT 312 2

3. Possible Types of Solutions solid in solid e.g. brass solid in liquid e.g. sugar water solid in gas e.g. mothball in air liquid in solid e.g. dental amalgam liquid in liquid e.g. ethanol in water liquid in gas e.g. water in air gas in solid e.g. hydrogen in palladium gas in liquid e.g. O2 in water gas in gas e.g. oxygen in nitrogen Of the nine possible types of solutions, you are probably most familiar with those in which the solvent is a liquid, especially those in which the solvent is water. PHT 312 3

4. Advantage of solutions Liquid are easier to swallow A drug must be in solution before it can be absorbed A solution is an homogenous system, the drug will be uniformly distributed throughout the preparation Some drugs can irritate the gastric mucosa if localized in one area Irritation is reduced by administration of a solution of the drug. PHT 312 4

5. Problem associated with the manufacturing of solutions Liquids are bulky and inconvenient to transport and store The stability of ingredients in aqueous solution is often poor than in solid dosage form Solution provide suitable media for the growth of micro-organisms and may require the addition of preservative Accurate dose measuring The taste of a drug is always pronounced when it in solution PHT 312 5

6. All solutions are characterized by interactions between the solvent phase and solute molecules or ions that result in a net decrease in free energy. Under such a definition, gases typically cannot function as solvents, since in the gas phase interactions between molecules are minimal due to the large distances between the molecules. This lack of interaction is the reason gases can expand freely and the presence of these interactions is the reason liquids do not expand. PHT 312 6

7. The components of a solution may be classified into solvent and solute Difference between solute and solvent PHT 312 7

8. Aqueous solutions and non-aqueous solutions Aqueous solutions Solutions that contain water as the solvent are called aqueous solutions. For example, sugar in water, carbon dioxide in water, etc.  Non-aqueous solutions Solutions that contain a solvent other than water are called non-aqueous solutions. Ether, benzene, petrol, carbon tetrachloride etc., are some common solvents.or example, sulphur in carbon disulphide, naphthalene in benzene, etc.  PHT 312 8

9. Concentrated solutions and dilute solutions Between two solutions, the solute quantity may be relatively more or less. The solution that has a greater proportion of solute is said to be more concentrated than the other that has a lesser proportion. If the proportion of solute is less, the solution is said to be dilute.  PHT 312 9

10. Saturated and unsaturated solutions Saturated Solution  A solution in which no more solute can be dissolved at a given temperature is called a saturated solution Unsaturated solution A solution in which more solute can be dissolved at a given temperature is called an unsaturated solution. A given solution that is saturated at a particular temperature may become unsaturated when the temperature is increased. PHT 312 10

11. Solubility and Miscibility Have you ever noticed that certain substances like table salt dissolve in water easily while other like caulk do not? Different substances have different solubilities. Solubility refers to the maximum amount of a solute that can be dissolved in an amount of solvent under specific temperature and pressure conditions. A substance that cannot be dissolved in another (or does so to a very limited extent) is said to be insoluble. PHT 312 11

12. Solubility of a solute Solubility is defined as the number of grams of a solute that dissolves in 100g of a solvent to form a saturated solution at a given temperature and pressure.  Solubility is the maximum weight of a solute that can be dissolved in 100g of a solvent at a given temperature and pressure Solubility = Wt of solute in saturated solution ? 100 Wt of solvent in saturated solution   PHT 312 12

13. Relative terms of solubility parts 0f solvent required for 1 part of solute Very soluble ? 1 Freely soluble 1-10 Soluble 10-30 Sparingly soluble 30-100 Slightly soluble 100-1000 Very slightly soluble 1000-10,000 Practically insoluble ? 10,000 PHT 312 13

14. Miscibility refers to the ability of a liquid to dissolve in another in all proportions. Alcohols like methanol and ethanol are miscible with water. There is no limit to the amount of these alcohols that can be dissolved in water - they dissolve in all proportions. When the amount of one liquid exceeds the other, their roles reverse. For example if you add alcohol to water, alcohol is said to be dissolved in water; however, if you add alcohol to the point where its volume is greater than the volume of water, then water becomes the solute and alcohol the solvent. When a liquid does not dissolve in another to any extent, the liquids are said to be immiscible. Oil and water are immiscible. PHT 312 14

15. Electrolytes and Non-Electrolytes One way to distinguish between solutions that contain ions and those that contain molecules is an electrical conductivity test. PHT 312 15

16. A solution that conducts electrical current is said to be electrolytic and the solute is called an electrolyte. The sodium chloride solution is an electrolytic solution. The solute in a solution that does not conduct electrical current is a non-electrolyte.. Examples include: sugar, urea, glycerol, and methylsulfonylmethane (MSM. sugar, urea, glycerol, and methylsulfonylmethane (MSM. Generally, dissociated ionic compounds are electrolytes whereas dissolved molecular compounds are non-electrolytes. The exceptions to this rule are the molecular acids.  PHT 312 16

17. Formation of an Aqueous Solution So how is it that salt and sugar crystals disappear when you add them to water? Aqueous solutions are those in which the solvent is water. They form in at least three ways depending on the nature of the solute: PHT 312 17

18. molecular solvation dissociation ionization Molecular solvation is a process whereby water molecules attract, surround and disperse solute molecules. The key term in this description is "attract". The potential solute and solvent molecules are more likely to form a solution if they have some common structural features. This idea is summarized in the generalization "like dissolves like“ PHT 312 18

19. Dissociation and ionization are processes that do involve changes in the structure of the solute. Dissociation is the separation of cations (positive ions) and anions (negative ions) in an ionic solid. It can occur as a result of collisions between the compound and water molecules. As the compound dissolves, water molecules attract, surround, and disperse the individual ions thereby separating them from each other.  In general terms, ionization is a process in which an atom or a molecule becomes an ion. In the context of aqueous solution formation, we use the term ionization to represent the formation of aqueous cations and anions from the interaction of water and a molecular substance. Molecular acids undergo ionization in water. PHT 312 19

20. Acids are defined theoretically as species that ionize in water to produce hydrogen ions and negative ions (anions). Empirically, they are defined as species that turn blue litmus red, neutralize bases, and react with active metals and carbonates to produce gases.  Acids form electrically conductive solutions; therefore they are electrolytes. However, only a few of them are strong electrolytes. When certain acids are added to water, only some of the molecules separate into hydrogen ions (the cations) and anions. The remainder of the acid molecules remain intact (do not form ions) and therefore cannot carry electrical current. Solutions containing some ionized some unionized molecules are termed weakly electrolytic. Solutions in which all the acid molecules ionize are termed strongly electrolytic. PHT 312 20

21. Units of Measure in Solutions Concentrations are often given in terms of weight/volume.  For example, mg/L, or mg/100 mL (common clinical units), are used.  These units do not depend on knowledge of the molecular structure of the measured substance. For a substance with a known molecular structure, one can define a "Mole" of that substance. 1 Mole is the weight of 6.023X10^23 molecules, and is commonly calculated as the sum of the atomic weights of each atom in a molecule. A Molar Solution is an aqueous solution consisting of one mole of a substance plus enough water to make one Liter of solution. A Molal Solution is an aqueous solution consisting of one mole of a substance plus 1 kg of water (usually very close to 1 L water).  The total volume may thus be more than 1 L. PHT 312 21

22. Concentrations of ions are often given in Equivalents (or milliequivalents, mEq) per Liter.  The equivalents of an ion is equal to the molarity times the number of charges per molecule.  Thus Equivalents is the measure of CHARGE concentration. Osmoles refers to the number of impermeable particles dissolved in a solution, regardless of charge.  This will be important for determining the diffusional movement of water.  For substances that maintain their molecular structure when they dissolve (e.g. glucose), the osmolarity and the molarity are essentially the same.  For substances that dissociate when they dissolve, the osmolarity is the number of  free particles times the molarity.   Thus for a pure NaCl solution, a 1 Molar solution would be 2 Osmolar (1 for Na, and 1 for Cl). PHT 312 22

23. Terms of expression the strength of pharmaceutical preparations % w/v 1g in 100 mL preparation %v/v 1mL in 100 mL preparation % w/w 1 g in 100 g preparation Ratio strength: weight in volume (1:1000 w/v= 1g constituent in 1000 mL preparation) Ratio strength :volume in volume (1:1000 v/v = 1ml constituent in 1000 mL preparation) Ratio strength : weight in weight (1:1000 w/w = 1 g constituent in 1000 g preparation) PHT 312 23

24. Factors Affecting Solubility Temperature will affect solubility. If the solution process absorbs energy then the solubility will be INCREASED as the temperature is increased. If the solution process releases energy then the solubility will DECREASE with increasing temperature  Mechanical stirring Mechanical stirring increases solubility. For example, sugar dissolves faster on stirring with a spoon. pH of the solvent (examples include weak acids and weak base) PHT 312 24

25. Molecular Size will affect the solubility. The larger the molecule or the higher its molecular weight the less soluble the substance will be Larger molecules are more difficult to surround with solvent molecules in order to solvate the substance. In the case of organic compounds the amount of carbon "BRANCHING" will increase the solubility since more branching will reduce the size (or volume) of the molecule and make it easier to solvate the molecules with solvent. PHT 312 25

26. An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending aq) to the relevant formula). As water is an excellent solvent as well as naturally abundant, it is a ubiquitous solvent in chemistry. Substances that do not dissolve well in water are called hydrophobic )'water fearing') whereas those that do are known as hydrophilic )'water-loving'). An example of a hydrophilic substance would be the (sodium chloride (ordinary table salt. PHT 312 26

27. Some solvents for liquid preparations: Aqueous solutions Types of pharmaceutical water Purified water, USP Water for injection Aromatic water Physiological compatibility Lack of toxicity Possesses a high dielectric constant, ensuring the dissolution of a wide range of ionizable materials Lack of selectivity PHT 312 27

28. Alcohol The most useful solvent in pharmacy (orally and parenterally) It form hydroalcoholic mixture with water that dissolves both alcohol-soluble and water-soluble substances It is miscible with water and can dissolve many water-insoluble ingredients, including drug substances, flavorants, preservatives. It is used as antimicrobial preservative (15%) Toxicity of ingested alcohol particularly for children. PHT 312 28

29. Diluted alcohol Is prepared by mixing equal volumes of alcohol and purified water Alcohol, Rubbing Alcohol rubbing compound It contains about 70% ethyl alcohol by volume It is employed as a rubefacient externally and as soothing rub for bedridden patients, a germicide for instruments As vehicle for topical preparation As skin cleanser before injection PHT 312 29

30. Glycerol It is a clear syrup liquid with sweet taste It is miscible with water and alcohol As solvent it is compatible with alcohol It is used as a stabilizer and as auxiliary solvent It has preservative qualities It is used in internal preparations Isopropyl rubbing alcohol Is about 70% by volume isopropyl alcohol, with or without colour additives, stabilizers and perfume oils It is used externally as a rubefacient and soothing rub and for topical products It is less likely to be abused PHT 312 30

31. Propylene glycol A viscous liquid, miscible with water, glycerol and alcohol It is substituted for glycerol in modern pharmaceutical preparations It is used for formulation of digoxin, diazepam, phenobarbital injection As diluent for ear drops PEG 400 Is used as a solvent in topical solution Used as cosolvent with alcohol and water Can be used for extraction processes In the formulation of veterinary solutions PHT 312 31

32. Ethyl ether Used for extraction of crude drugs It is used as a cosolvent with alcohol in some collodions It is not used for internal use Liquid paraffin It is unplasent to use externally It is used as a solvent for topical application of drugs in emulsion formulations PHT 312 32

33. Dimethylsulfoxide It is used as a solvent for veterinary drugs It is used for application to human skin Miscellaneous solvents Isopropyl myristate, isopropyl palmitate are solvent for external use, cosmetics Low vsicous, lack of greasiness Xylene is used in ear drops for human use to dissolve ear wax PHT 312 33

34. Other formulation additives Buffers Injection, eye drops and nasal drops should be buffered at pH 7.4 Ex: carbonates, citrates, phosphate, lactates, gluconates, tartarates, borates (external) Density modifier Ex: dextrose Isotonicity modifier Ex: dextrose and sodium chloride Viscosity enhancement Low conc., of gelling agents can be used to increase the apparent viscosity of the product Ex: povidone, carbomer, hydroxyethylcellulose PHT 312 34

35. Preservatives Ex: parahydroxybenzoic acid esters Reducing agent and antioxidants Ex: sodium metabisulphite, butylated hydroxanisole or butylated hydroxytoluene Sweetening agent Ex: sucrose, polyhydric alcohols: sorbitol, mannitol, artificial sweeteners: sodium or calcium salt of saccharin Flavours and perfumes To mask the unpalatable taste, ex: fruit juices, aromatic oils, herps Colours To improve the attractiveness of the product and to enable ease of identification Ex: carotenoids, chlorophyll, riboflavines, coal tar dyes PHT 312 35

36. According to partticular pharmaceutical solution’s use may be classified as: Oral Otic Ophthalmic Nasal Topical According to the composition or use, solutions may be classified as : Aqueous solution containing sugar are termed syrups Sweetened hydroalcoholic solutions are termed elixirs Solution of aromatic materials are termed spirits Solutions prepared by extracting active constituents from crude drugs are termed tinctures PHT 312 36

37. Oral solutions Dry mixtures for solution Certain antibiotics have insufficient stability in aqueous solution to meet extended shelf life periods They are provided in dry powders or granules for reconstitution before use Once reconstituted, the solution remain stable for 7-14 days depending on the condition of storage Examples: Penicillin V Potasium for oral solution, USP Cloxacillin Sodium for oral solution, USP PHT 312 37

38. Oral rehydration solutions Are usually effective in treatment of diarrhea and mild volume depletion (5-10% of body weight). These are available OTC Oral solution contains: 45mEq Na+, 20 mEq K+, 35 mEq CL-, 30 mEq citrate, 25 g dextrose in 1 Liter These formulations are available in liquid or powder packets form for reconstitution These products should not be mixed with milk or fruit juice Oral colonic lavage solution Used for preparation of the bowel for colonoscopy Composed of oral solution of electrolytes with PEG-3350. Before dispensing it to the patient, the solution is reconstituted with water, creating an iso-osmotic solution. PEG is an osmotic agent in the GIT The formulation is as follows: PEG-3350; Sodium sulfate; sodium bicarbonate; sodium chloride; potassium chloride PHT 312 38

39. Sodium citrate and citric acid oral solution Solution contains sodium citrate 100 mg and citric acid 67 mg /mL of aqueous solution. The solution is administered oraly in 10-30 mL as frequently as 4 times daily as a systemic alkalinizer. The solution is a useful adjuvant when administered with uricosuric agents in gout therapy PHT 312 39

40. Syrup In cooking, a syrup (from Arabic ???? sharab, beverage, via Latin siropus) is a thick, viscous liquid, containing a large amount of dissolved sugars, or sugar substitute with or without flavoring agents and medicinal substances. Viscosity arises from the multiple hydrogen bonds between the dissolved sugar, which has many hydroxyl(OH) groups, and the water. Technically and scientifically, the term syrup is also employed to denote viscous, generally residual, liquids, containing substances other than sugars in solution. Syrup containing flavoring agents but not medicinal substances are called nonmedicated or flavored vehicles (syrup). PHT 312 40

41. The syrup employed as a base for medicinal purposes consists of a concentrated or saturated solution of refined sugar in distilled water. The "simple syrup" of the British Pharmacopoeia is prepared by dissolving 85 g of refined sugar in purified water to make 100 mL of syrup. The specific gravity of the syrup should be 1.313. Flavoured syrups are made by adding flavouring matter to a simple syrup. For instance, syrupus aromaticus is prepared by adding certain quantities of orange flavouring and cinnamon water to simple syrup. Similarly, medicated syrups are prepared by adding medicaments to, or dissolving them in, the simple syrup. PHT 312 41

42. Examples of medicated syrup: Analgesic Anticholenergic Antiemetics Anticonvulsant Antihistamine Antiviral Antitussives Expectrorant Bronchodilators PHT 312 42

43. As syrups can contain up to 85% of sugars, they are capable of resisting bacterial growth by virtue of their osmotic effect. Syrup, NF, also called simple syrup. The amount of preservative required to protect a syrup against microbial growth varies with the proportion of water available for growth Preservative commonly used in syrups : benzoic acid 0.1-0.2%, sodium benzoate 0.1-0.2%, parabens. To enhance the appeal of the syrup, a coloring agent that correlates with the flavorant employed (green with mint, brown with chocolate). Most syrups are flavored with synthetic flavorants or with naturally occurring materials, such as volatile oils (orange oil), vanilin In cool storage some sucrose might crystallize from solution Sucrose-based syrup may be substituted by a polyol, such as sorbitol solution USP, 64% PHT 312 43

44. Elixirs An elixir (From Arabic,??????? ) are clear , sweetened hydroalcoholic solutions intended for oral use and usually flavored to enhance their palatability. Non-medicated elixirs are employed as vehicles. Elixirs are usually less sweet and less viscous than syrup. In addition to alcohol and water, other solvents, such as glycerol and propylene glycol are frequently employed in elixirs as adjunctive solvents. PHT 312 44

45. Elixirs are sweetened with sucrose, sorbitol, glycerol, and/or artificial sweeteners Most elixirs have coloring agents to enhance their appearance Elixirs containing more than 10-12% alcohol are usually self-preserving and don't require the addition of antimicrobial preservatives Because of their usual content of volatile oils and alcohol, elixirs should be stored in tight, light-resistant containers and protected from excessive heat Antihistamine Elixirs: Diphenhydramine HCl Analgesic Elixirs: acetominophen Cardiotonic Elixirs: digoxin Antispasmodic elixir: hyoscyamine sulfate Se dative Elixirs: phenobarbital PHT 312 45

46. Tinctures In medicine, a tincture is an alcoholic extract (e.g. of leaves or other plant material) or solution of a non-volatile substance; e.g. of iodine, mercurochrome). To qualify as a tincture, the alcoholic extract is to have an ethanol percentage of at least 40-60% (sometimes a 90% percent pure liquid is even achieved). Solutions of volatile substances were called spirits, although that name was also given to several other materials obtained by distillation, even when they did not include alcohol. PHT 312 46

47. Tinctures contain alcohol in amounts ranging from approx. 15-80%. The alcohol content protects against microbial growth Other solvent, such as glycerol, may be employed Tincture must be tightly stoppered and not exposed to excessive temperature Many tinctures must be stored in light-resistant containers and protect from sunlight. Some examples that were formerly common in medicine include: Tincture of Cannabis sativa Tincture of Benzoin Tincture of cantharides Tincture of ferric citrochloride (a chelate of citric acid and Iron(III) chloride) Tincture of green soap ( (which also contains lavender) Tincture of guaiac Tincture of iodine Tincture of opium (laudanum) Camphorated opium tincture (paregoric) PHT 312 47

48. Tincture of iodine is often found in emergency survival kits, used both to disinfect wounds and to sanitize surface water for drinking. When an alcohol solution is not desirable, Lugol's iodine, an aqueous solution of iodine in potassium iodide solution, or povidone iodine (Betadine), a PVPI solution, can be used. Elemental iodine is toxic. Children and pregnant women, who are more sensitive to it, should avoid its use. Human metabolism requires trace amount of iodine, but as the iodide salt (a compound), not as the free element. The need for iodine as iodide is satisfied by iodized salt and many seafoods. When using free iodine to sanitize surface water, it should be left to sit for 30 minutes before drinking, allowing time for all viruses and bacteria to be killed. If the water temperature is less than 20 °C (68 °F), sitting time should be extended to several hours. To purify 1 L (34 oz) of water, 0.3 mL (0.01 oz) of 2% tincture should be used. Cold or cloudy water should be given 2.4 mL (0.08 oz) of 2% iodine, and should be left to sit for several hours. PHT 312 48

49. Lugol's iodine, also known as Lugol's solution, first made in 1829, is a solution of elemental iodine and potassium iodide in water, named after the French physician J.G.A. Lugol. Lugol's iodine solution is often used as an antiseptic and disinfectant, for emergency disinfection of drinking water, and as a reagent for starch detection in routine laboratory and medical tests. Lugol's solution consists of 5 g iodine (I2) and 10 g potassium iodide (KI) mixed with 85 ml distilled water, to make a brown solution with a total iodine content of 130 mg/mL. Potassium iodide renders the elementary iodine soluble in water through the formation of the I3- ion. It is not to be confused with simple tincture of iodine solutions, which consist of elemental iodine dissolved in alcohol. Lugol's solution contains no alcohol. Other names for Lugol's solution are I2KI (Iodine-Potassium Iodide); Markodine, Strong solution (Systemic); Aqueous Iodine Solution BP. PHT 312 49

50. Linctuses A viscous preparation , usually for the relief of cough It consists of a simple solution of the active agent in a high concentration of sucrose The syrup content has a demulcent action on the mucous membranes of the throat For diabetic use , the sucrose is replaced by sorbitol or synthetic sweeteners This type of product, should be sipped slowly and not be diluted beforehand It is administered in multiple of 5 mL PHT 312 50

51. Topical solutions Aluminum acetate (Burow’s solution) Is colourless and has a faint acetous odor, is applied topically as an astringent wash or wet dressing after dilution with 10 to 40 parts of water. Used in various types of dermatological lotions Commercial tablets are available for preparation of this solution Calcium hydroxide It is called Limewater, contain not less than 140 mg of Ca(OH)2 in each 100 mL of solution Cool purified water is the solvent The solution is intended to be saturated with solute The solution should be stored in well-filled tightly stoppered containers and kept in a cool place to maintain an adequate conc., of dissolved solute. The solution is astringent and is employed in dermatological solutions and lotions PHT 312 51

52. Hydrogen peroxide It contains 2.5-3% w/v hydrogen peroxide H2O2, suitable preservative may be added (0.05%) Is a clear, colorless liquid. It deteriorates upon long standing also by the effect of light and heat The solution should be preserved in tight, light-resistant containers, at temp. not exceeding 35 ?C It is categorized as a local anti-infective for use topically on the skin or mucous membranes. Its germicidal activity is based on the release of nascent oxygen on contact with the tissues and its ability to cleanse wounds Synonym: peroxide PHT 312 52

53. Povidone iodine Commercial product: Betadine It is a chemical complex of iodine with PVP It contains approx. 10% available iodine and slowly released when applied to the skin It is employed as surgical scrub and nonirritating antiseptic solution Thimerosal topical Is a water-soluble organic mercurial antibacterial agent used topically for its bacteriostatic and mild fungistatic properties It is used to disinfect skin and as an application to wounds and abrasions It has been also applied to the eye, nose, throat in dilution 1:5000 It is also used as a preservative for various preparations The solution is affected by light and must be maintained in light resistant containers PHT 312 53

54. Topical tinctures Iodine Tincture It is a reddish-brown colour tincture It is prepared from 2% iodine crystal and 2.4% sodium iodide in a vehicle alcohol/water (44-50% alcohol) It is a popular local anti-infective agent applied to the skin in general household first aid Compound Benzoin tincture It is prepared from 10% benzoin and lesser amounts of aloe, storax and tolu balsam The mixture is macerated in alcohol It is used to protect and toughen skin in the treatment of bedsores, ulcers, cracked nipples, and fissures of the anus Also used in treatment of venereal warts It is also used as an inhalent for bronchitis and other respiratory conditions It is best stored in tight, light-resistant containers PHT 312 54

55. Thimerosal Tincture The vehicle is water, acetone and 50% alcohol It must be manufactured and stored in glass or suitably resistant containers Ethylenediamine is used as stabilizer in the official solution and tincture The commercial preparation is colored orange red, the colour defines the area of application It is a commonly used household antiseptic for application to the skin abrasions and cuts and in preparation of patients for surgery Green Soap tincture 65% of active constituent in alcohol Also contains 2% lavender oil as perfume Used as detergent PHT 312 55

56. Vaginal and rectal solutions Vaginal douches Solution for irrigation cleansing of the vagina, used for hygienic effect Solutions may be prepared from powders or liquid concentrates. The resultant solution contains the appropriate amount of chemical agents in proper strength Boric acid – astringents - antimicrobial – quaternary ammonium compound – detergents – oxidizing agents – salts – aromatics Evacuation Enemas Rectal enemas are used to cleanse the bowel. The enema solution are solutions of; sodium phosphate, sodium biphosphate, glycerin, docusate sodium, light mineral oil The product will work within 5-10 min They are available in disposable plastic squeeze bottles Typical example: Soft soap 25 g / 500 mL water as an emollient PHT 312 56

57. Ear preparations Also known as otic products, these are simple solutions of drugs in water, glycerol, propylene glycol or alcohol/water mixture for local use Hydrogen peroxide (5-volume), Phenol (6% w/w) ear drops Ear drops are a form of medicine used to treat or prevent ear infections, especially infections of the outer ear and ear canal (Otitis externa). Bacterial infections are sometimes treated with antibiotics. Examples are:- Gentisone HC ear drops (containing Gentamicin and hydrocortisone). Ciproxin HC ear drops (containing ciprofloxacin and hydrocortisone). Kenacomb ear drops, containing triamcinolone acetonide, neomycin and gramicidin (antibiotics) and nystatin (antifungal). Over the counter ear drops are also available, including spirit drops (alcohol solution), which dries out the ear, and drops such as Aqua Ear (used for swimmer's ear) containing a mixture of substances such as alcohol and acetic acid, to dry the ear and make it difficult for microbes to grow. PHT 312 57

58. Eye preparations Eye drops are sterile aqueous or oily solutions or suspensions intended for instillation into the eye. Depending on the condition being treated, they may contain steroids (e.g. mydriatics, dexamethasone), antihistamines, sterile sympathomimetics, beta receptor blockers, parasympathomimetics (e.g. pilocarpine), parasympatholytics (e.g. tropicamide or atropine), prostaglandins, non-steroidal anti-inflammatory drugs (NSAIDs) or topical anesthetics. Eye drops sometimes do not have medications in them and are only lubricating and tear-replacing solutions, and they can also contain anti-redness and similar chemicals. PHT 312 58

59. Nasal preparations These are formulated as small-volume solutions in an aqueous vehicle for instillation into the nostrils Formulation are isotonic with nasal secretions using sodium chloride. Viscosity can be modified using cellulose derivatives Nasal administration can be used to deliver drugs for either local or systemic effect. Locally acting drugs are for example decongestants and allergy treatments. Examples of systemically active drugs available as nasal sprays are migraine drugs, nicotine replacement and hormone treatments.  PHT 312 59

60. Irrigations Are sterile , large volume aqueous–based solutions for the cleansing of body cavities (peritoneal dialysis solution) and cleansing wounds. They should be made isotonic with tissue fluid Spray An aqueous or oleaginous solutions in the form of coarse droplets or as finely divided solids to be applied topically, most usually to the nasopharyngeal tract or to the skin by means of an atomizer The type of atomizer used depends on the viscosity of the spray solution Drugs used for relief of asthma are commonly dispensed as spray PHT 312 60

61. Topical dental solution Oromucosal preparations: are designed for application to the throat or oral cavity and can includes solids and semi-solids as well as solutions Mouthwashes and gargles These aqueous solutions are for the prevention and treatment of mouth and throat infections and can contain antiseptics, analgesics and / or astringents They are intended to bring the medication into contact with mucous surface of the throat They are usually diluted with warm water before use Gargles may have some analgesic effect and provide symptomatic relief Mouthwash are intended to wash out the mouth , they may be of value for local hygiene of the mouth PHT 312 61

62. Gingival and sublingual preparations These are in the form of drops or sprays for application to specific areas of the oral mucosa such as the gums for the prevention and treatment of periodontal disease or under the tongue to enable fast absorption of active agents into systemic circulation PHT 312 62

63. Non aqueous solutions Liniments Are liquid preparation for external use only and may be applied with or without friction. They should not be applied to unbroken skin They are alcoholic or oleaginous solutions or emulsions of various medicinal substances For oleaginous liniments, the solvent may be a fixed or volatile oil (almond, sesame, peanut, wintergreen, turpentine oil) Alcoholic or hydroalcoholic vehicle are useful when rubefacient or counterirritant action is desired For relief of pain, they may be applied on warmed flannel or lint or may be painted with a soft brush Liniment may be alcoholic solutions They should be dispensed in colored bottle PHT 312 63

64. Paints Liquids for application to the skin or mucous membranes in small amounts using a small brush The solvent is water, alcohol, ether or acetone Glycerol is often added to ensure prolonged contact with the skin (viscocity modifier) Collodions Is a clear viscous liquid prepared by dissolving pyroxylin in a 3:1 mixture of ether and alcohol or acetone/alcohol Pyroxylin obtained by the action of a mixture of nitric and sulfuric acids on cotton, consists of cellulose tetranitrate The resulting solution is highly volatile and flammable The product is capable of forming a protective film on application to the skin PHT 312 64

65. Castor oil may be applied to collodion to render the film flexible, permitting its comfortable use After evaporation of the solvent leaves a tough , flexible film hold the drug in intimate contact with the skin Salicylic acid Collodion It is 10% solution of salicylic acid in flexible collodion Has keratolytic effect especially in the removal of corns from the toes The product is applied as one drop on the corn or wart, allowing time to dry As salicylic acid is irritant to normal skin, it should be applied directly on the corn or wart PHT 312 65