صيدلانيات (1) PDF - PHARMACEUTICS I Course Notes

ELECTRONIC COURSE ‫ﻣﻌﺘﺼﻢ ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ of PHARMACEUTICS I for SECOND LEVEL PHARM...

ELECTRONIC COURSE ‫ﻣﻌﺘﺼﻢ ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ of PHARMACEUTICS I for SECOND LEVEL PHARM D PHARMACY STUDENTS Course Code: PT 302 2024/2025 2024/2025 2024/2025  COURSE CONTENTS ‫ﻣﻌﺘﺼﻢ ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Items Routes of administration of drugs Dosage forms Medication order Posology and dosage regimen Pharmaceutical calculations Solutions Liquids as oral dosage form Incompatibilities 2024/2025 2024/2025 2024/2025 Solutions for administration into body cavities Liquids for external use Powders Questions Bank ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ 2024/2025 2024/2025 2024/2025 Pharmaceutics I This course work may be used only for the university`s educational purposes. It includes extracts of copyright work copied under copyright license. You may not copy or distribute any part of this coursepack to any other person. Where this coursepack is provided to you in electronic format you may only print from it for your own use. You may not make a further copy for any other purpose. Failure to comply with the terms of this warning may expose you to legal action for copyright infringement and/ or disciplinary action by the university. 1 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Introduction 2024/2025 2024/2025 2024/2025 ◼ Pharmaceutics include dispensing and pharmaceutical technology. ◼ Dispensing is the supply of medicine to patient according to a prescription. ◼ dispensing involves clarification of the prescriber`s wishes, preparation and labelling the medicine. ◼ Dispensing includes the art of compounding and utilizing information. 2 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Introduction 2024/2025 2024/2025 2024/2025 ◼ Pharmaceutical technology involves the technology necessary for formulation and preparation of dosage forms. ◼ Dosage forms are the mean by which drugs are delivered to the site of action within the body. ◼ They can be classified according to the route of administration or according to their nature. 3 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: A- Those intended for systemic effect 2024/2025 2024/2025 2024/2025 ◼ Oral route: ◼ Involves administration of drug orally to be absorbed in the gastrointestinal tract (GIT). ◼ It is the most common. ◼ Convenient for self administration. ◼ Suitable for most drugs except those that are rapidly inactivated in GIT. 4 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: A- Those intended for systemic effect 2024/2025 2024/2025 2024/2025 ◼ Oral route: ◼ Drugs may be degraded by the stomach pH or by digestive enzymes. ◼ Not suitable in case of vomiting or unconscious. ◼ Absorption is slow and may be incomplete. ◼ Problems from first pass effect. 5 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: A- Those intended for systemic effect 2024/2025 2024/2025 2024/2025 ◼ Buccal and sublingual route: ◼ Involves administration of drug into the buccal cavity or under the tongue. ◼ Can avoid some of the problems of oral route. ◼ Very rich with blood capillaries providing rapid drug absorption. ◼ Absorbed drugs reach the systemic circulation avoiding the first pass effect. 6 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: A- Those intended for systemic effect 2024/2025 2024/2025 2024/2025 ◼ Rectal route: ◼ Involves insertion of the drug into the rectum. ◼ The drugs are absorbed mainly to the systemic circulation. ◼ This route is useful for drugs known to cause GI irritation. ◼ It is also useful for comatosed patient or in case of vomiting. 7 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: A- Those intended for systemic effect 2024/2025 2024/2025 2024/2025 ◼ Inhalational route: ◼ Involves administration of the drug into respiratory system by inhalation. ◼ The high blood flow and large surface area of the alveoli provide a route for rapid absorption of drugs. ◼ This route is useful for anaesthetic gases, volatile liquids and drugs that can be dispersed in aerosol form. ◼ The nasal mucosa can also be used as a route for systemic administration (NASAL route). 8 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: A- Those intended for systemic effect 2024/2025 2024/2025 2024/2025 ◼ Transdermal route: ◼ Involves absorption of the drug into the systemic circulation after application of the drug on the skin. ◼ Useful for drugs that have short half life (t1/2) ◼ Only suitable for potent drugs. 9 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: A- Those intended for systemic effect 2024/2025 2024/2025 2024/2025 ◼ Parenteral route: ◼ Involves administration of the drug by injection. ◼ Intravenous route (i.v.) delivers the drug into the circulation. Injection volume varies from a fraction of ml up to 500ml. 10 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: A- Those intended for systemic effect 2024/2025 2024/2025 2024/2025 ◼ Parenteral route: ◼ Drugs can be absorbed rapidly after intramuscular (i.m) injection of aqueous solution. ◼ Slower absorption can take place after subcutaneous injection (s.c.). ◼ Other parenteral routes include: ◼ Intra-articular (into joints), Intraocular (into eye), Intracardiac (into the heart) and intracisternal (into C.S.F) 11 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: B- Those intended for local effect 2024/2025 2024/2025 2024/2025 ◼ Oral route: ◼ In this case drug absorption is not required. ◼ This includes drugs which can exert local action on the GIT such as adsorbents, antimicrobials and antacids. 12 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Routes of administration of drugs: B- Those intended for local effect 2024/2025 2024/2025 2024/2025 ◼ Topical route: ◼ In this case drug is applied to the epithelium covering the body. ◼ Provides local action at the site of application. ◼ Includes dosage forms applied to skin, cornea of the eye, the nasal, rectal, vaginal or urethral mucosa 13 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ ‫‪Dosage forms‬‬ ‫‪2024/2025‬‬ ‫‪2024/2025‬‬ ‫‪2024/2025‬‬ ‫‪14‬‬ ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Tablets: ◼ These are solid dosage form intended for oral administration and prepared by compression. ◼ Each tablet contains a single dose of drug(s). ◼ They can be swallowed with water ◼ They can be chewed before swallowing (chewable tablets). ◼ They can be dispersed in water before administration (dispersible and effervescent tablets) 15 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Pills: ◼ These are solid oral dosage form which consist of spherical masses prepared from one or more active ingredients incorporated with inert excepient. ◼ Pills are rarely used. ◼ The term pill is used incorrectly to describe oral contraceptive tablets which are prepared by compression. 16 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Cachets: ◼ These are solid dosage form moulded from rice paper and used to enclose quantities of powder (up to 2 grams). ◼ They are now rarely dispensed. ◼ In the past they were used to administer unpleasantly tasting powdered drugs. ◼ Because of large size they must be immersed in water for few seconds before swallowing 17 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Capsules: ◼ These are solid oral dosage form made of gelatin and is used to mask the unpleasant taste of their content and/or to protect drug from deteriorating conditions. ◼ There are two types of capsules: ◼ Hard gelatin capsules. ◼ Soft gelatin capsules 18 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Hard gelatin capsules: ◼ The capsule consists of body and cap fitted together after filling. ◼ This type is used for solid medicaments which may be in the form of powder, spheres or compressed mass. 19 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Soft gelatin capsules: ◼ The capsule is in the form of one piece which is formed, filled and sealed in one manufacturing operation. ◼ Their contents are usually in the form of liquid. ◼ The liquid content can be solution or dispersion in non-aqueous liquid. 20 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Powders (oral): ◼ These are solid oral dosage form available in two kinds: ◼ Bulk powders: usually contain non-potent drugs such as antacids and the patient measures the dose by a spoonful. This is usually dispersed in before use. ◼ Divided powders: These are packaged individually as unit dose. Each dose is wrapped in a paper or sealed in a sachet. 21 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Powder for mixtures ◼ These are powders mixed in the preparation of standard suspension type mixture. ◼ The mixed powders are stored in dry form and reconstituted by the pharmacist when needed. 22 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Granules ◼ These are solid oral dosage form of irregular particles of 0.5-2 mm in diameter. ◼ These are usually supplied in single dose sachets. ◼ They may be placed on the tongue and swallowed with water or dissolved in water before use. ◼ Effervescent granules evolve carbon dioxide when added to water. 23 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Syrup (Syr.) ◼ This is concentrated aqueous solution of sugar (sucrose). ◼ It can be used as vehicle for syrup dosage form. ◼ The flavoring syr. is used to mask the bitter taste of drugs. ◼ Sucrose can lead to dental decay so sorbitol may be better. 24 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Linctuses ◼ This are viscous liquid oral preparations that are usually prescribed to relief cough. ◼ They usually contain high proportion of syrup or glycerol which have demulcent effect. ◼ The dose is 5ml and should be undiluted. ◼ Elixirs ◼ These are pleasantly flavored clear liquid oral preparation of potent or nauseous drugs. ◼ The vehicle may contain high proportion of ethanol. 25 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Oral emulsion ◼ Fine dispersion of droplets of an oily liquid in an aqueous liquid (aqueous phase) which acts as the continuous phase. ◼ Drugs may be dispersed in oily or aqueous phase. ◼ Mixtures ◼ These are liquid oral preparations consisting of one or more medicaments dissolved or suspended in aqueous vehicle. 26 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Solutions ◼ These are liquid preparations containing one or more dissolved ingredients. ◼ They may be used for internal or external purpose ◼ Lozenges ◼ These are solid preparations consisting mainly of sugar and gum. ◼ Gum gives strength and cohesiveness to the lozenges and gives slow release of drug. ◼ They are used to treat mouth and throat. They can treat indigestion and cough. 27 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Pastilles ◼ These are solid medicated preparations designed to dissolve slowly in the mouth. ◼ They are softer than lozenges and their base is either glycerol and gelatin or acacia and sugar. ◼ Gargles ◼ These are aqueous solutions used for prevention and treatment of throat infections. ◼ They are usually prepared in concentrated form and must be diluted. ◼ Mouth washes are similar to gargles but used for oral hygiene and to treat mouth infection. 28 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Eye drops ◼ These are sterile solutions or suspensions of one or more medicaments intended for instillation into the conjunctival sac. ◼ They may be packed in multiple application container or in single dosage form. ◼ Eye lotions ◼ These are sterile aqueous solutions used for bathing the eye. ◼ Sterile solution of bactericide may be used as first aid to the eye and must be discarded within 24 hours after opening the container. 29 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Eye ointments ◼ These are sterile semisolid preparations intended for application to the conjunctiva or eyelid. ◼ The medicament is dissolved or dispersed in non- irritant base. ◼ Ear drops ◼ These are solutions, suspensions or emulsions of drug intended for instillation into the ear with a dropper. 30 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Sprays ◼ These are preparations of drug in aqueous, alcoholic or glycerol containing media. ◼ They are applied to mucous membranes of the nose, throat with suitable atomizer or nebulizer. ◼ Insufflations ◼ These are medicated powder designed to be blown into ear, nose, throat or body cavities by means of insufflator. 31 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Nasal drops and sprays ◼ Drug solution can be instilled into the nose from a dropper or plastic squeeze bottle. ◼ The drug may be antihistaminic, vasoconstrictor or decongestant. ◼ Drugs may be absorbed from nasal mucosa providing systemic effect (e.g. peptide drugs). ◼ Oily nasal drops is prohibited due to damage of cilia. ◼ Prolonged use of vasoconstrictor leads to rebound vasodilatation and further nasal congestion. 32 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Inhalations ◼ These are liquid preparations containing volatile substances. They are used to relief congestion and inflammation of respiratory tract. ◼ Pressurized inhalations ◼ These are solutions, suspension or emulsions of drug in a mixture of inert propellants hold under pressure in aerosol dispenser. They release metered dose by spring-valve having metering device. ◼ They are inhaled through mouth piece. 33 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Pressurized aerosol dispensers ◼ Many types of pharmaceutical products can be packed in aerosol dispenser. These can provide surface spray for surface disinfection or for wounds or burn dressing ◼ Suppositories ◼ These are solid preparations designed for insertion into the rectum where they melt, dissolve or disperse to provide local or systemic effect. 34 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Enemas ◼ These are solutions, suspension or emulsions for rectal administration. ◼ Pessaries ◼ These are solid medicated preparations for insertion into the vagina. It can be: ◼ Moulded pessaries. ◼ Compressed (Vaginal tablets). ◼ Vaginal capsules (soft gelatin) 35 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Irrigation solutions ◼ These are sterile pyrogen-free solutions intended for irrigation of body cavities, operation wounds or urogenital systems. ◼ Ointments ◼ These are semisolid, greasy preparations for application to skin, rectum or nasal mucosa ◼ Creams ◼ These are semisolid emulsions for external use. They be o/w or w/o 36 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Gels ◼ These are translucent or transparent non-greasy semisolid preparations mainly used externally. ◼ The gelling agent may be gelatin, starch, sodium alginate or cellulose derivative. ◼ Pasts ◼ These are semisolid preparations for external application that differ from ointment and creams in containing high proportions of fine powder ◼ The base may be anhydrous (paraffin) or water soluble such as glycerol 37 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Poultices ◼ These are paste like preparations for external use to reduce pain and inflammation. They are usually applied after warming ◼ Liniments ◼ These are fluid or semisolid preparations for application to skin. They may be alcoholic or oily solutions or emulsions. 38 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Colloidions ◼ These are liquid preparations for application to skin. ◼ Pyroxylin is dissolved in volatile liquid (ether or ethanol) and forms protective film after evaporation. ◼ It can be used to provide prolonged contact with the skin ◼ Lotions ◼ These are liquid preparations for application to skin without friction. 39 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Paints ◼ These are liquid preparations for application to skin and mucous membranes. ◼ Skin paints often have volatile solvent which evaporate leaving resinous film. ◼ Throat paints are viscous due to high content of glycerol which increases the contact time. ◼ Dusting powders ◼ These are free flowing very fine powder for external use. ◼ It should not be used on open wound unless sterilized. 40 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Implants ◼ These are sterile disks or cylinders introduced surgically into the body tissues and designed to release one or more drugs over long period of time. ◼ Parenteral preparations ◼ These are sterile dosage forms containing one or more drugs and designed for administration by injection. 41 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage forms 2024/2025 2024/2025 2024/2025 ◼ Parenteral preparations ◼ Ampoules: contain liquids (solution, suspension or emulsion) in aqueous or non-aqueous vehicle. May contain powder. ◼ Vials: generally contain powder for injection after reconstitution. May contain liquid ◼ Large volume parenterals (i.v. infusion): Sterile aqueous solutions, free from pyrogen and administered by infusion. 42 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Sources of information 2024/2025 2024/2025 2024/2025 ◼ Pharmacopoeia, Formularies and Medicines legislation ◼ The word pharmacopoeia is derived from the Greek word “pharmacon” which means a drug. The suffix “poeia” means I make. ◼ The pharmacopoeia provides a list of medicinal substances, crude drugs and formulae for making pharmaceutical preparations of them. ◼ This list is prepared by recognized authorities approved by the government (ministry of health) of each country. 43 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Sources of information 2024/2025 2024/2025 2024/2025 ◼ Pharmacopoeia, Formularies and Medicines legislation ◼ Most of the principal countries have their own pharmacopoeia. ◼ The British Pharmacopoeia (BP) ◼ The international pharmacopoeia (IP) ◼ The European Pharmacopoeia (EP) ◼ The United states Pharmacopoeia (USP) ◼ The British Pharmaceutical Codex (BPC) ◼ The British National Formulary (BNF) ◼ The Extra Pharmacopoeia (Martindale) 44 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Medication order 2024/2025 2024/2025 2024/2025 ◼ Medicines may be ordered for a patient by a licensed physician, or other authorized prescriber. ◼ The order is usually recorded by the prescriber on a prescription form or on a physician`s order form. ◼ The prescription is used for office patient or hospital outpatient but the physician order form is for hospital inpatient. ◼ Oral transmission of medication order by prescriber is permitted except for controlled drug. 45 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Medication order 2024/2025 2024/2025 2024/2025 ◼ Prescriptions are usually issued to patients and dispensed by pharmacist to the patient. ◼ The physician order is usually issued to a nurse who obtains the medicine from the pharmacist. ◼ A limited number of medications may be supplied by the pharmacist to the nurse or nursing station in advance as floor or ward stock. 46 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ ‫‪2024/2025‬‬ ‫‪2024/2025‬‬ ‫‪2024/2025‬‬ ‫‪47‬‬ ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Interpreting the order 2024/2025 2024/2025 2024/2025 ◼ The physician`s original written medication order must be checked carefully by the pharmacist for legibility and accuracy. ◼ In case of oral transmission of the order, the pharmacist should document it in writing immediately and completely. ◼ Transmission of a medication order to the pharmacist by any mean other than the original written form should be discouraged to reduce the possibility of errors 48 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ It is an order from a doctor, dentist or veterinary practitioner or veterinary surgeon for the supply of medicine, dressing or appliance to a patient (or owner of animal). ◼ It can be hand written, typewritten or computer written or in some occasions it can be verbally transmitted via telephone. ◼ The prescription should be checked and responded by the pharmacist. 49 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ The prescription which is intended for use by patient at home should contain the following information: ◼ Patient name, address and age if under 12years. ◼ The name and quantity of medicament to be supplied. ◼ Instructions for the patient. ◼ The prescriber`s profession, address and signature. ◼ The date on which the prescription was written and signed ◼ Proper labelling requirement. ◼ A request for repeat dispensing may be included but not for National Health Services (NHS) prescriptions. 50 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ Patient name, address and age ◼ The title of the patient (Mr. Miss, …) together the surname and/or the full name of the patient is useful when dealing with more than one prescription from the same family. These details should be included on the label. ◼ The age of child under 12 years is a legal requirement and will help the pharmacist to check the dose. ◼ The address should be clear. It is a legal requirement and is useful when delivering the medicine to the patient home or when keeping records. 51 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ The names and quantities of medicine to be supplied ◼ Prescribers are recommended to write the name of medicine in full (BNF) but many use abbreviations and the pharmacist should ensure that the abbreviations are not misinterpreted. ◼ The medicament may be prescribed as: ◼ A- Official preparation prescribed by non-proprietary (generic) name and complying with the specified reference (BP, USP, …) ◼ B- Preparation prescribed by non-proprietary (generic) name which is not defined in official reference. ◼ C- Product by brand name. ◼ D- A special formula in which the name and quantity of ingredients and the type and amount of the product (lotion, cream,..) is stated. In some cases the active ingredient is stated and the pharmacist uses his skills to select the additives. 52 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ The names and quantities of medicine to be supplied ◼ In UK it is recommended to use generic name (chemical name) but in some cases different manufacturer may have products of different bioavailability. ◼ Each medicine can be available in many dosage forms so the type of dosage form must be specified. ◼ The strength of the preparation must be stated also. 53 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ The names and quantities of medicine to be supplied ◼ The quantity of medicine can be expressed as: ◼ A- weight or volume. ◼ B- number of doses (e.g. 20 tablets, 20 capsules, …) ◼ C- a number of manufacturer`s original packs (e.g. 1OP, 6 OP). ◼ D- as a daily dose together with the number of days of treatment (e.g. 1 x 3 x 10, this means you should supply 30 doses) 54 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ Instructions for the patient ◼ The instructions may include: ◼ A- The quantity to be taken or amount to be used ◼ B- The frequency and timing of administration. ◼ C- The route of administration and method of use. ◼ D- Special instructions such as dilution direction 55 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ The prescriber`s profession, address and signature ◼ This can give some indication on the prescription whether the prescriber is doctor, dentist or veterinary. This is legal requirement for some medicine ◼ The date on which the prescription was written and signed ◼ There is a legal requirement for prescribers to date the prescriptions for some classes of medicines. There may also be a time limit after which the prescription will not be valid. 56 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ Proper labelling requirement ◼ It is common practice to label the medicine by name and instructions for use. e.g. one tablet to be taken three times daily after meals. ◼ A request for repeat dispensing ◼ A repeatable prescription is that which contains a direction that it may be dispensed in more than one occasion. ◼ Repeatable prescription is not acceptable for NHS or controlled drugs 57 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ Bulk prescription ◼ Prescriptions are usually written for one named patient. ◼ Certain items may be ordered in bulk for schools and institutions for 20 or more patients on NHS prescription form. ◼ The name of institution and number of patients replace the patient name. 58 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ Incomplete prescription ◼ Before dispensing the prescription the pharmacist must be sure that all legal requirements are fulfilled. ◼ The legal requirement vary according to the category of prescription. ◼ Prescriptions that are not legally complete must be referred back to the prescriber before dispensing. ◼ For non-controlled drug, the pharmacist can contact the physician via telephone to complete the missing part (e.g. strength, quantity, dosage, …..) 59 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The prescription 2024/2025 2024/2025 2024/2025 ◼ Incomplete prescription ◼ If the prescriber can not be contacted the pharmacist can use his knowledge to complete the missing information but if there is any doubt, the patient must be referred back to the prescriber. ◼ For NHS prescription in which the quantity is missing, the pharmacist may supply the smallest original pack or he may supply enough medicine for 5 days. 60 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The form of the prescription (main parts of the prescription) 2024/2025 2024/2025 2024/2025 ◼ 1. The superscription ◼ It is the uppermost part of prescription and is simply represented by the sign R/. ◼ The sign R/ is the abbreviation of the Latin word recipe which means take those (for patient) or prepare the following prescription (for pharmacist) ◼ 2. The inscription ◼ It is the general body of prescription. ◼ It comprises a list of ingredients and the quantity of each to be supplied. 61 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ The form of the prescription (main parts of the prescription) 2024/2025 2024/2025 2024/2025 ◼ 3. The subscription (directions for the pharmacist) ◼ These directions include the type of product to be dispensed (mixture, tablet, capsules, …) and the dose and number of doses to be dispensed. ◼ 4. The Signature ◼ These are directions to the patient including the size of dose, frequency of dosing and route of administration. ◼ This must be translated by the pharmacist into label. 62 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Posology and dosage regimen: 2024/2025 2024/2025 2024/2025 - Posology: (Derived from the Greek posos, how much, and logos, science) is the branch of medicine/pharmacy dealing with doses. - Dose: is the quantitative amount administered or taken by a patient for the intended medicinal effect. 63 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage: 2024/2025 2024/2025 2024/2025 - The idea being to produce the optimum therapeutic effect in a particular patient with the lowest possible dose. - The familiar bell-shaped curve shows that: 1- In a normal distribution of patients, a drug’s usual dose will provide an average effect in the majority of individuals. 2- In a portion of the patients, the drug will produce little effect (resistant individuals). 3- In another group of similar size, the drug will produce an effect greater than the average effect (Sensitive individuals). So, the drug’s usual dose would be the starter dose for an individual taking the drug for the first time, then the physician may increase or decrease subsequent doses to meet the requirements of his patient. 64 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ 2024/2025 2024/2025 2024/2025 Drug effect in a population sample (Dose – response curve) 65 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 Factors affecting drug dosage: 1- Age: - Newborn infants (pediatric) are abnormally sensitive to certain drugs because of the immature state of their hepatic and renal function by which drugs are inactivated and eliminated from the body. - Failure to detoxify and eliminate drugs results in their accumulation in the tissues to a toxic level. - - The decline in renal and hepatic function in elderly may slow drug excretion leading to drug accumulation and toxicity. - Elderly individuals may also respond abnormally to the usual amount of a drug because of changes in drug-receptor sensitivity or because of age-related alterations in target tissues and organs. 66 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 Various rules of dosage in which the pediatric dose was a fraction of the adult dose: 1- Young’s rule, based on age: - For calculating doses for children two years of age or older. Age (yr) Dose for child = Adult dose x Age (yr) + 12 67 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 2- Body weight: - The official usual doses for drugs are considered suitable for 70 kg (150 pounds) individuals. - - The ratio between the amount of drug administered and the size of the body influences the drug concentration at the site of action. - Therefore, drug dosage may require adjustment from the usual adult dose for abnormally lean or obese patients. 68 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 To calculate the dose of a drug for children based on body weight: The determination of drug dosage for children on the basis of body weight is more dependable than that based on age. Clark’s Rule: Weight (in Ib) Dose for child = Adult dose x 150 (average weight of adult in Ib) 69 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 3-Sex: - Women are more susceptible to the effects of certain drugs than are men. - Pregnant women and nursing mothers should use medications only with the advise and under the guidance of their physician. - The transfer of drugs from the mother to the nursing infant through human milk may occur with various drugs with the drug effects becoming manifest in the infant. 70 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 4- Pathological state: - The effects of certain drugs may be modified by the pathological condition of the patient and must be considered in determining the dose. - Warning and precautions are used in the drug labeling to alert the physician to certain restrictions in the use of a particular drug. 71 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 A- Precaution: Is used to advise the prescriber of some possible problems attendant with the use of the drug. It is less restrictive than warning. e.g. The use of tetracycline antibiotic may result in overgrowth of fungi. In such a case, the physician may prescribe an alternate drug. B- Warning: It is used when the potential for patient harm is greater than in instances in which the precaution is used. 72 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 e.g. If tetracycline is used in the presence of renal impairment, it may lead to accumulation of the drug and possible liver toxicity. So, - Lower than usual doses are indicated. C- Contraindication: A term that is used to indicate an absolute prohibition to the use of a drug in presence of certain stated conditions. It is the most restrictive of the warnings which limits the use of drugs. 73 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 5- Tolerance: Drug tolerance: Reduced effect of drug due to repeated use. - Tolerance occurs commonly in such drugs e.g. antihistaminics, narcotic analgesics. - Normal sensitivity may be regained by stopping drug administration for a period of time. - The development of tolerance can be minimized by: I. Initiating therapy with the lowest effective dose. II. Avoiding prolonged administration. 74 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 6- Drug-drug interactions: - The effects of a drug may be modified by the concurrent administration of another drug. This can be manifested as: 1- Synergism (increased effect). 2- antagonism (reduced effect) 75 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 7- Time of administration: - The time at which a drug is administered sometimes influences dosage. This is specially true for oral therapy in relation to meals. - Absorption proceeds more rapidly if the stomach and upper portions of the intestinal tract are free of food, and an amount of a drug that is effective when taken before a meal may be ineffective if administered during or after eating. 76 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Factors affecting drug dosage (Cont.): 2024/2025 2024/2025 2024/2025 8- Route of administration: - Drugs administered intravenously enter the blood stream directly and thus the full amount administered is present in the blood. - In contrast, drugs administered orally are rarely fully absorbed due to the various physical, chemical and biologic barriers to their absorption, including interactions with the gastric and intestinal contents. - Thus, a lower parenteral dose of a drug is required than the oral dose to achieve the same blood levels of drug. 77 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage regimen: 2024/2025 2024/2025 2024/2025 - The schedule of dosing (e.g., four times a day for 10 days) is referred to as the dosage regimen. - The proper selection of both the dose size and the frequency of administration is an important factor that influences whether a satisfactory therapeutic plasma concentration is achieved and maintained over the prescribed course of treatment. 78  ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ‬ MTC Duration of action 2024/2025 2024/2025 2024/2025 tmax Therapeutic range ‫ﺍﻟﻤﻮﺯﻯ‬Concentration MEC AUC Onset tmax Time Time A blood curve for a drug as a function of the time following oral administration. 79 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage regimen (Cont.): 2024/2025 2024/2025 2024/2025 Definitions: Minimum effective concentration (MEC): The minimum concentration that can be expected to produce the drug’s desired effects in 50% of the individuals tested. Minimum toxic concentration (MTC): The minimum concentration which produces toxic effects in 50% of the individuals tested. Therapeutic index: It is the ratio between a drug’s minimum toxic dose and minimum effective dose (TD50%) / ED50%). - ↑↑ therapeutic index is more favorable as it means that the drug is safe. - Some drugs have low therapeutic index e.g. digoxin (TI = 2). 80 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage regimen (Cont.): 2024/2025 2024/2025 2024/2025 How to design a satisfactory dosage regimen…..??? - The aim of drug therapy is to achieve a plasma concentration of drug which lies within the therapeutic range of that drug. 1- If the interval between each dose is longer than the time required for complete elimination of the previous dose, the plasma concentration-time profile of a drug will exhibit a series of isolated single-dose profiles. The design of this dosage regimen is unsatisfactory as the plasma concentration lies below the drug therapeutic range for long periods and so the patient will be under medicated (reduced or no therapeutic effect). 81 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ 2024/2025 2024/2025 2024/2025 Plasma concentration-time curve following oral administration of equal doses of a drug at time intervals that allow complete elimination of the previous dose. 82 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage regimen (Cont.): 2024/2025 2024/2025 2024/2025 2- If the dosing time interval is shorter than the time required for complete elimination of the previous dose, a steady state (drug concentration remains within therapeutic range) is reached which corresponds to the achievement and maintenance of maximal clinical effectiveness of the drug in the patient. 83 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ 2024/2025 2024/2025 2024/2025 Plasma concentration-time curve following oral administration of equal doses of a drug. (a steady state is reached) 84 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage statements: 2024/2025 2024/2025 2024/2025 The dosage regimen: The schedule of dosage. It is indicated for those drugs that are best taken at specific intervals e.g. every 8 hours , e.g. at bedtime, e.g. before meals. Initial loading or priming dose: It is a large single dose of the drug may be administered initially in order to achieve a peak plasma concentration that lies within the therapeutic range, which may then be maintained through the subsequent administration of regularly scheduled maintenance doses. e.g. digoxin (cardiotonic agent) Initially administered four or more times a day, followed by a single daily dose to maintain the desired blood level of the drug. 85 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Dosage statements: 2024/2025 2024/2025 2024/2025 Maintenance doses: Smaller, equal doses that administered at suitable fixed intervals to maintain the plasma concentrations of a drug. Prophylactic doses: doses that may be administered to protect the patient from contracting a specific disease, such as vaccines. Therapeutic dose: Which is administered to a patient after exposure or contraction of the illness. 86 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Working from master formula (MF) ◼ You need to calculate the dispensing factor (D.F). ◼ D.F. = (amount required/total amount in MF) ◼ 1. Calculate the amount of ingredients required for 150ml opium squill linctus ◼ Master formula Required amounts ◼ R/ Squill oxymel ……… …... 300ml X 1/6 = 50ml ◼ Comphorated opium Tr … 300ml X 1/6 = 50ml ◼ Syr. Tolu ……………….. 300ml X 1/6 = 50ml ◼ D.F. = 150/900 = 1/6 87 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Working from master formula (MF) ◼ 2. Calculate the amount of each ingredients required to prepare 200ml of chloral hydrate mixture ◼ Master formula Required amounts ◼ R/ Chloral hydrate……… …... 2 g X 20 = 40 g ◼ Syrup ………………….… 2 ml X 20 = 40ml ◼ Water to..……………….. 10 ml X 20 = to 200ml ◼ D.F. = 200/10 = 20 88 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Working from master formula (MF) ◼ 3. Calculate the amount of each ingredients required to prepare 30g of the following ointment ◼ Master formula Required amounts ◼ R/ Bees wax …..……… …... 20 g X 3/100 = 0.6 g ◼ Hard paraffin …….… 30 g X 3/100 = 0.9 g ◼ cetostearyl alcohol …….. 50 g X 3/100 = 1.5 g ◼ soft paraffin ……. ….. 900 g X 3/100 = 27 g ◼ D.F. = 30/1000 = 3/100 89 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Working from master formula (MF) ◼ 4. Using the following master formula for a paste, calculate the amounts required to prepare 25g of the paste ◼ Master formula Required amounts ◼ R/ Coal tar …..……… …... 6 g X 1/4 = 1.5 g ◼ Starch … ……….… 20 g X 1/4 = 5 g ◼ Zinc oxide …………….. 20 g X 1/4 = 5 g ◼ soft paraffin ……. ….. 54 g X 1/4 = 13.5 g ◼ D.F. = 25/100 = 1/4 90 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 Percentage concentrations ◼ ◼ Percentage weight in volume (% w/v) ◼ This indicates the number of grams of ingredient in 100ml of the product ◼ Example: Prepare 100 ml of sodium chloride solution (0.9% w/v) BP 1988. ◼ Master formula ◼ R/ Sodium chloride …............................ 0.9 g ◼ water (freshly boiled and cooled) to.… 100 ml ◼ 91 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 Percentage concentrations ◼ ◼ Percentage weight in weight (% w/w) ◼ This indicates the number of grams of ingredient in 100gm of the product ◼ Example: Prepare 100 g of syrup BP 1988 (66.666 % w/w) (about 66.7% w/w) ◼ Master formula ◼ R/ Sucrose …………............................ 66.7 g ◼ water (freshly boiled and cooled) to.… 100 g ◼ 92 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 Percentage concentrations ◼ ◼ Percentage volume in volume (% v/v) ◼ This indicates the number of milliliters of ingredient in 100ml of the product ◼ Example: Prepare 300 ml of wintergreen liniment (methyl salicylate liniment, 25% v/v) ◼ Master formula Required amounts ◼ R/ methyl salicylate … …... 25 ml X 3 = 75 ml ◼ Eucalyptus oil……….… 10 ml X 3 = 30 ml ◼ Arachis oil to ………….. 100 ml X 3 = to 300 ml ◼ D.F. = 300/100 = 3 93 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Concentrations expressed as parts ◼ The strength may be expressed as “parts” of dissolved substance in “parts” of solution. ◼ In case of solution of solid in liquid, it will be parts (weight) in parts (volume). ◼ In case of solution of liquid in liquid, it will be parts (volume) in parts (volume). ◼ To prepare solution of certain concentration you need to convert parts to concentration ◼ For example: ◼ 1 in 100 = (1/100) x 100 = 1% ◼ 1 in 200 = (1/200) x 100 = 0.5% ◼ 1 in 500 = (1/500) x 100 = 0.2% 94 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Preparing dilutions ◼ 1- Calculate the volume of benzalkonium chloride solution (50% w/v) needed to prepare 150ml of dilute benzalkonium chloride solution (10% w/v). ◼ Method 1: ◼ Concentration factor = (50%/10%) = 5 times ◼ So the dilute solution is obtained by diluting (150/5) = 30ml of the concentrated solution with water to 150ml. 95 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Preparing dilutions ◼ 1- Calculate the volume of benzalkonium chloride solution (50% w/v) needed to prepare 150ml of dilute benzalkonium chloride solution (10% w/v). ◼ Method 2: ◼ Vc x Cc = Vd x Cd ◼ Vc x 50 = 150 x 10 ◼ Vc = 30ml ◼ So the formula will be ◼ R/ ◼ Benzalkonium chloride (BP) …….. 30 ml ◼ Water to ………………………….. 150ml 96 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Preparing dilutions ◼ 2- Calculate the volume of strong cetrimide solution (40% w/v) required to prepare 200ml of cetrimide solution containing 1% w/v. ◼ Vc x Cc = Vd x Cd ◼ Vc x 40 = 200 x 1 ◼ Vc = 200/40 = 5 ml ◼ So the formula will be ◼ R/ ◼ Strong cetrimide solution …….. 5 ml ◼ Water to …………………….. 200ml 97 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Antiseptic solutions for dilution by patient ◼ 1- Calculate the quantity of potassium permanganate required to prepare 200ml of 0.25% w/v solution and give dilution directions to prepare 100ml quantities of dil. Pot. permang. solution (0.0125% w/v). ◼ The formula for conc. solution (0.25% w/v): ◼ R/ ◼ Pot permanganate …….. 0.25 g x 2 = 0.5g ◼ Water to ……………… 100ml x 2 = to 200ml ◼ Dilution directions: ◼ Vc x Cc = Vd x Cd ◼ Vc x 0.25 = 100 x 0.0125 ◼ Vc = 5 ml ◼ So the patient should dilute 5ml of the conc solution to 100ml with water. 98 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 Antiseptic solutions for dilution by patient ◼ ◼ 2- Give the dilution directions to prepare 500ml quantities of 1 in 5000 solution of Pot. permang. From the 0.25% w/v solution. ◼ Convert (1 in 5000) to % w/v ◼ 1 in 5000 = (1/5000) x 100 = 0.02% w/v ◼ Dilution directions: ◼ Vc x Cc = Vd x Cd ◼ Vc x 0.25 = 500 x 0.02 ◼ Vc = 40 ml ◼ So the patient should dilute 40ml of the conc solution to 500ml with water to prepare 1 in 5000 solution. 99 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Antiseptic solutions for dilution by patient ◼ 3- Calculate the quantity of proflavin required to prepare 300ml of 1/1000 solution and give dilution directions to prepare 200ml quantities of a 1 in 4000 solution. ◼ The formula for conc. solution (1/1000): D.F. = 300/1000 = 3/10 ◼ R/ quantity required ◼ Proflavin ……….…….. 1 x (3/10) = 0.3g ◼ Water to ……………… 1000 x (3/10) = to 300ml ◼ Convert parts to % w/v ◼ 1/1000 = (1/1000) x 100 = 0.1% w/v & 1/4000 = (1/4000) x 100 = 0.025% w/v ◼ Dilution directions: ◼ Vc x Cc = Vd x Cd ◼ Vc x 0.1 = 200 x 0.025 ◼ Vc = 50 ml ◼ So the patient should dilute 50ml of the conc solution to 200ml with water. 100 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Concentrated stock solutions ◼ 1- Calculate the quantity of concentrated cinnamon water required to prepare 300ml of fresh cinnamon water. N.B. fresh cinnamon water is prepared by diluting 1 volume of conc. Cinnamon water to 40 volumes with water. ◼ Conc. Cinnamon water Fresh cinnamon water ◼ 1 40 ◼ X 300 ◼ X = (300/40) = 7.5 ml ◼ So the formula for fresh cinnamon water will be ◼ R/ quantity required ◼ Conc cinnamon water….…….. 7.5 ml ◼ Water to ……………………. to 300ml 101 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Dilution of liquid oral dosage forms ◼ 1- How can you respond to a prescription of 25ml chloral elixir pediatric which is to be labeled as 2.5ml to be taken at night ◼ Here the preparation must be diluted to 5ml doses and the recommended diluent is syrup. ◼ dilute to ◼ So 2.5 ml 5ml ◼ dilute to ◼ 25 ml X ◼ X = (25 x 5)/2.5 = 50 ml So the dispensing formula will be as follow and the dose will be 5ml at night ◼ R/ ◼ Chloral elixir….…….. 25 ml ◼ Syrup to …………… 50ml 102 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations 2024/2025 2024/2025 2024/2025 ◼ Dilution of liquid oral dosage forms ◼ 2- Calculate the volume of salbutamol syrup containing 2mg/5ml required to prepare 100ml of salbutamol syrup containing 1.5mg/5ml ◼ Concentration of strong syr. = 2/5 = 0.4 mg/ml ◼ Concentration of dilute syr. = 1.5/5 = 0.3 mg/ml ◼ Cc x Vc = Cd xVd ◼ 0.4Vc = 0.3 x 100 ◼ Vc = 300/4 = 75ml So the dispensing formula will be R/ ◼ Salbutamol syr (2mg/ml)….…….. 75 ml ◼ Purified water to ………………... 100ml 103 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations: 2024/2025 Triturations 2024/2025 2024/2025 ◼ Trituration is a term applied for grinding materials in the mortar, mixing substances or diluting active ingredient with inert substance. ◼ Small quantities of powder ◼ If the active ingredient is too small to be weighed, the minimum weighable quantity (100mg) of the material is mixed with inert substance such as lactose to produce 1 in 10 or 1 in 100 dilution. But it is essential to make sure that mixing is efficient 104 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations: 2024/2025 Triturations 2024/2025 2024/2025 ◼ Calculate the amount of ingredients required to prepare 4 doses of divided powder each containing 500mg diazepam. ◼ It is better to prepare one extra dose. ◼ The diluent is lactose ◼ Minimum weight for divided powder is 120mg ◼ Calculations: ◼ 1- weight of diazepam in 5 doses = 5 x 500 = 2500mg = 2.5mg ◼ 2- weight of lactose for 5 doses = (5x120) – 2.5 = 597.5mg ◼ Formula ◼ R/ ◼ Diazepam ………….. 2.5 mg ◼ Lactose to …………. 600 mg ◼ But the quantity of drug is too small to be weighed in one step. So we should use dilution method by trituration. 105 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Pharmaceutical calculations: 2024/2025 Triturations 2024/2025 2024/2025 ◼ Trituration 1 mix diazepam ◼ Diazepam ………100 mg 1000 100 mg ◼ Lactose ………900 mg 100 10 mg ◼ Trituration 2 ◼ Trituration 1……100 mg 1000 10 mg ◼ Lactose ………900 mg x 2.5 mg ◼ Trituration 3 x = 250mg ◼ Trituration 2…… 250 mg ◼ Lactose to …….. 600 mg ◼ So 600 of trituration 3 will contain 2.5mg ◼ Each 120mg will contain 0.5mg = = 500mg ◼ So each 120mg aliquot of trituration 3 will contain 1 dose. 106 ‫ﻭﺍﺋﻞ ﻣﺤﻤﺪ ﻣﺤﻤﻮﺩ ﺍﻟﻤﻮﺯﻯ‬ Solutions 2024/2025 2024/2025 2024/2025 ◼ These are homogenous liquid prepa