introduction to pharmaceutics.pptx

Outline
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 Introduction to pharmaceutics
 Pharmaceutical excipients
 For Solid dosage forms
 For liquid dosage forms

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After this lesson the students are expected to
 Know what does pharmaceutics mean
 Know what active pharmaceutical ingredient is
 Understand the meaning and function of pharmaceutical
excipients
 Identify different excipients used for different types dosage
forms
Objectives

 There are many chemicals with known pharmacological
properties ► Active pharmaceutical ingredient (API)
 Chemical compound with pharmacological effect (or other direct
effect ) intended for use in
 Diagnosis
 Treatment
 Prevention of diseases
 International non-proprietary names (INN, generic names)
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Introduction

Direct clinical use of the API, ‘as they are’
is rare due to the number of good reasons:
 API handling can be difficult or impossible (e.g., low mg and g
doses)
 Accurate drug dosing can be difficult or impossible
 API administration can be impractical, unfeasible or not
according to the therapeutic aims
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 Some API can benefit from reducing the exposure to the
environmental factors (light, moisture…), or they need
to be chemically stabilized due to the inherent chemical
instability
 API can be degraded at the site of administration (e.g.,
low pH in stomach)
Introduction…

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 API may cause local irritations or injury when they are
present at high concentrations at the site of
administration
 API can have unpleasant organoleptic qualities (taste,
smell – compliance!)
Introduction…

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 Medicinal products must meet the following requirements
that underpin EFFICACY, SAFETY, and QUALITY:
1. Contain an accurate dose
2. Be convenient to take or administer
3. Provide the drug in a form for absorption or other delivery
to the target
4. Retain quality throughout the shelf life and usage period
Introduction…
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 No APIs have meet all these criteria
 Therefore, it is necessary to add other materials to make good
any shortfalls
 Consequently, virtually every medicinal product is a
combination of the drug substance and excipients
 These are crucial components of medicinal products and, in
most cases comprise the greatest proportion of the dosage unit.
Introduction…
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 The science that deals with the formulation of a pure drug
substance into a dosage form (Dosage form design)
Pharmaceutics
 Pharmaceutical dosage forms are API + excipients added to
alleviate the above problems
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Introduction…

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Pharmaceutical excipients

Pharmaceutical excipients…
 Excipients are pharmacologically inert materials that are
combined with APIs to
 Aid their processing into dosage forms (e.G. Tablets, injections and
ointments)
 Facilitate API administration to patients
 They required to be pharmacologically, chemically and
physically inert, safe, with more quality
 The most convenient classification of excipients
► The functions they perform in dosage formulations
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Excipients for solid dosage forms
Diluents (or fillers)
 Diluents are fillers used to increase the bulk volume of a
tablet or capsule
 Increase the mass of the tablets and capsule that contain a low
concentration of therapeutic agent
 Actual API doses can be as low as ~20μg, e.G. For oral steroids
• Thereby render the manufacturing process more reliable and
reproducible
 Diluents must exhibit good compression properties and be
inexpensive, compatible ,inert and resistant to microbial growth
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Classification of diluents
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 Natural diluents
 Starch (old)
 Organic diluents
 Lactose(low moisture content & low hygroscopity)-good for
moisture sensitive drugs.
 Sucrose, mannitol, sorbitol, micro crystalline cellulose (MCC)
 Inorganic diluents
 Dibasic calcium phosphate anhydrate (dihydrate)
 Tribasic calcium phosphate
 The inorganic diluents do not exhibit binding properties when
they are used in direct compression and wet granulation
 For example, in the preparation of tablets or capsules
of tetracycline antibiotics, a calcium salt should not
be used as a filler since calcium interferes with
absorption of the antibiotics from the GI tract

Binders
 Binders are predominantly (but not exclusively) polymeric
components used to hold API and excipient in a cohesive mix
 Give adherence to powder mixtures → necessary mechanical
strength
 In this role, binders are either added as a solution or as a solid
into the powder mix (following which the granulating fluid,
typically water, is added)
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Classification of binders
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 According to their chemical source
 Saccharides and their derivatives
 Disaccharides: sucrose, lactose
 Polysaccharides and their derivatives
 Starch, MCC, HPMC(Hydroxypropyl Methyl Cellulose)
 Natural gum: acacia, tragacanth
 Protein: gelatin
 Synthetic polymers: polyvinylpyrrolidone(PVP),
polyethylene glycol(PEG)

Disintegrants
 Disintegrants are employed in tablet formulations to facilitate the
breakdown of the tablet into granules upon entry into the stomach (15
minutes)
 Mode of action:
 ↑ the porosity and wettability of the compressed tablet matrix
 Water uptake rupturing the intra-particle cohesive forces that hold the
tablet together → disintegration
 Operate by swelling in the presence of aqueous fluids
Water uptake → swelling →physical rupture →widened the channels for
penetration of water → disintegration
 Example: sodium starch glycolate, crospovidone, croscarmellose sodium
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Lubricants
 These are used to reduce friction between powders and metal surfaces
during tablet manufacture
 During compression lubricants act at the interface between the face of
the die and the surface of the tablet
 Lubricants tend to be hydrophobic, so their levels (typically 0.3 – 2%)
need to be optimized
 Under-lubricated blends tend to flow poorly and show compression sticking
problems
 Over-lubricated blends can adversely affect tablet hardness and dissolution
rate
 Example: Magnesium stearate
 WATER SOLUBELE TYPE: Sodium Lauryl Sulfate, PEG 4000 & PEG
6000
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Glidants
 Glidants act to enhance the flow properties of the powders
within the hopper and into the tablet die in the tablet press
 By reducing the friction between the powders/granules due to the
ability of the particles of the glidants to locate within the spaces
between the particles/granules
• Glidant particles to be small
• Arrange at the surface of the particles/granules
 Example: Colloidal silicon dioxide (traditionally, talc was used)
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Organoleptic excipients
Sweetening agents/flavoring agents
 Sweetening and flavoring agents are employed to control the taste
and hence the acceptability of tablets
 More important
 If the conventional tablet contains a bitter drug
 If the tablet is a chewable tablet
Colorants
 Colored tablets are generally formulated either to improve the
appearance or to identify the finished product uniquely
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Excipients For liquid dosage forms
The vehicle
 The preferred and most commonly used vehicle in liquid dosage forms is
Purified Water USP, due to the
 Low cost and toxicity
 Physical compatibility
 Good solubilizing power
Disadvantage
 Instability of hydrolytically unstable drugs
 Being good vehicle for microbial growth
 Co-solvents are employed to increase the solubility of the therapeutic agent
within the formulation
 Glycerol and ethanol
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Buffers
 Buffers are employed within pharmaceutical solutions to control
the pH of the formulated product
 Typically pH control is performed:
To maintain the solubility of the API in the formulated product
To enhance the stability of products in which the chemical stability of
API is pH-dependent
 Examples of buffer salts used in pharmaceutical solutions include:
Acetates (acetic acid and sodium acetate)
Citrates (citric acid and sodium citrate)
Phosphates (sodium phosphate and disodium phosphate)
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Antimicrobial preservatives
 Preservatives are used to control the microbial bio-burden of the
formulation
 Ideally, preservatives should exhibit the following properties:
Possess a broad spectrum of antimicrobial activity
Be chemically and physically stable over the shelf-life of the product
Have low toxicity
 Example:
 Benzoic acid and salts (0.1–0.3%)
 Sorbic acid and its salts (0.05–0.2%)
 Alkyl esters of parahydroxybenzoic acid (0.001–0.2%)
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Antioxidants
 Included to enhance the stability of therapeutic agents that are
susceptible to chemical degradation by oxidation
 Used to control oxidation of
 API, Preservative
 vehicle, e.g. oils or fats susceptible to β-oxidation
(rancidification)
 Colorants (ageing discoloration)
 They are sacrificial (more oxidisable than API, preservative, etc)
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Antioxidants…
Levels will reduce with time…. need to be monitored by specific
assay
 Light exposure and metal ion impurities can accelerate
oxidative degradation and hence depletion of API
 Examples:
 Sodium sulphite
 sodium metabisulphite
 sodium formaldehyde
 Sulphoxylate
 ascorbic acid
 Butylated hydroxytoluene (BHT)
 Butylated hydroxyanisole (BHA)
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Viscosity-enhancing agents
 Suspension stabilizers: prevent settling/sedimentation
 They usually modify viscosity and are often thixotropic (where
viscosity is dependent on applied shear and exhibits ‘shear
thinning’)
 Easily poured when shaken
 Must permit accurate dosing with chosen method (e.g. graduated syringe,
spoon)
 Quickly reforms ‘gel-like’ structure
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 Work by entrapment of solid particles, e.g. API, in a viscous or
even gel-like’ structure
 Example
 Methylcellulose,
 Hydroxyethylcellulose,
 Hydroxypropylcellulose
 Sodium carboxymethylcellulose
 Sodium alginate
 Certain liquid formulations do not require the specific addition of
viscosity-enhancing agents, e.g. syrups, due to their inherent
viscosity.
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Viscosity-enhancing agents…

Surface-active agents
 Surface-active agents are amphipathic compounds used to reduce
surface tension
 To aid ‘wetting’ and dispersion of a hydrophobic API, preservative or
antioxidant
 Not all are suitable for oral administration
 Examples include:
 Oral: polysorbates (Tweens), sorbitan esters (Spans)
 Parenteral: polysorbates, lecithin
 External: sodium lauryl sulphate
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Sweetening Agents
Natural sweeteners
 Sucrose; soluble in water (vehicle)
 Arguably the best taste/mouthfeel
 Sorbitol but lower sweetness intensity than sucrose (so you need
more)
Artificial sweeteners
 Much more intense sweeteners compared with sucrose
 Can impart a bitter or metallic after-taste (hence used in combination
with natural sweeteners)
 Examples: Saccharin and it’s salts Aspartame
 Sucralose – excellent sweetness, but relatively expensive
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Humectants
 Hygroscopic excipients used at ~5% in aqueous suspensions and
emulsions for external application.
 Function:
 To retard evaporation of aqueous vehicle of dosage form
 To prevent drying of the product after application to the skin
 To prevent drying of product from the container after first opening of a
container after first opening
Examples include:
o Propylene glycol
o Glycerol
o PEG
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Objectives
At the end of this lessen the students are able to
 Define pharmaceutical dosage forms
 Classify PDF based on origin, ROA and physical
properties
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Pharmaceutical dosage forms (PDF)
Definition:
 Dosage forms are the means by which drug molecules are
delivered to sites of action within the body.
 They are designed to facilitate the administration of drug
substances
 Contains API + inactive pharmaceutical ingredients (excipients)
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Preparation
processes
DRUGS
(Active
pharmaceutical
ingredients)
+ Pharmaceutical
excipients
MEDICINES
Pharmaceutical dosage…

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They are classified according to:
Route of administration
Oral
Topical
Rectal
Parenteral
Vaginal
Inhaled
Ophthalmic
Otic
Physical form
Solid
Semisolid
Liquid
Gas

Manufactured in large
scales by pharmaceutical
industry (original and
generic preparations)
They are classified according to the origin
 Compounded individually in
compounding pharmacies
 The drug in a particular DF is not
commercially available on the market
 The extraordinary low or high dose is
needed (young children, elderly people,
special situations – e.g., intoxications)
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• Solid dosage forms
• Semisolid dosage forms
• Liquid dosage forms
• Gaseous dosage forms
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Solid dosage forms
Tablet
 A tablet is a hard, compressed medication in round, oval or
square shape
 The API will be compressed along with other pharmaceutical
excipients
 Used as oral dosage form
 The excipients include:
 Binders, glidants and lubricants to ensure efficient tableting
 Disintegrants to ensure that the tablet breaks up in the digestive tract
 Sweeteners , flavors, Colorant
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A coating may be applied to:
1- Hide the unpleasant taste of the tablet's components to ma
2- Make the tablet smoother and easier to swallow
3- Make it more resistant to the environment
4- Control the toxicity of API in GIT
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Solid dosage forms…

Buccal and sublingual tablet
 Sublingual and buccal medications are administered by placing
them in the mouth, either under the tongue (sublingual) or
between the gum and the cheek (buccal).
 The medications dissolve rapidly and are absorbed through the
mucous membranes of the mouth, where they enter into the
bloodstream.
 Examples of drugs administered by this route: e.g. vasodilators
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Effervescent tablet
 Effervescent tablets are uncoated tablets that generally contain
acid substances (citric and tartaric acids) and carbonates or
bicarbonates and which react rapidly in the presence of water by
releasing carbon dioxide ↔ disintegration
 They are intended to be dissolved or dispersed in water before use
providing:
 Very rapid tablet dispersion and dissolution → rapid absorption
 Pleasant tasting carbonated drink.
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Chewable tablet
 Tablets are chewed within the buccal cavity prior to swallowing
 Advantage:
 Children and adults who have difficulty in swallowing conventional
tablets
 e.g. vitamin products
 Antacid formulations in which the size of the tablet is normally large
o Not used if the drug has issues regarding taste
acceptability
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Capsule
 A capsule is a medication in a gelatin container
 Advantage: mask the unpleasant taste of its contents
 The two main types of capsules are:
1- Hard-shelled capsules, which are normally used for dry,
powdered ingredients,
2- Soft-shelled capsules, primarily used for oils and for active
ingredients that are dissolved or suspended in oil
Soft gelatin capsule
Hard gelatin capsule
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Lozenge
 It is a solid preparation consisting of sugar and gum
 The latter giving strength and cohesiveness to the lozenge and
facilitating slow release of the medicament.
 It is used to medicate the mouth and throat for the slow
administration of indigestion or cough remedies.
o Dissolved slowly in the mouth
o Lubricate and soothe irritated tissues of the throat
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Granules
 They are consisting of solid, dry aggregates of powder particles
often supplied in single-dose sachets.
 Some granules are placed on the tongue and swallowed with
water, others are intended to be dissolved in water before taking.
 Effervescent granules evolve carbon dioxide when added to water.
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Powder
 There are two kinds of powder intended for internal use.
1-Bulk Powders: multi-dose preparations consisting of solid,
dry particles
 Usually contain non-potent medicaments such as antacids since the
patient measures a dose by volume using a 5ml medicine spoon.
 The powder is then usually dispersed in water
2-Divided Powders: single-dose presentations of powder ( for
example, a small sachet) that are intended to be issued to the
patient as such, to be taken in or with water.
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Suppository
 It is a small solid medicated mass, usually cone-shaped ,that
is inserted either into the rectum (rectal suppository) where
it melts at body temperature.
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Pessary
 Pessaries are solid medicated preparations designed for insertion
into the vagina where they melt or dissolve.
 There are three types:
A- Moulded pessaries : they are cone shaped and prepared in a similar
way to moulded suppositories.
B- Compressed pessaries: made in a variety of shapes and are prepared
by compression in a similar manner to oral tablets.
C- Vaginal capsules: are similar to soft gelatin oral
Capsules differing only in size and shape.
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Liquid dosage forms
Oral solution
 Oral solutions are clear liquid preparations for oral use containing
one or more active ingredients dissolved in a suitable vehicle.
Syrup
 It is a concentrated aqueous solution of a sugar, usually sucrose.
 No need of other sweetening agents and viscosity-modifying
agents
 No addition of preservatives is required
High concentration of
sucrose
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Elixir
 It is clear hydro-alcoholic solution for oral use
 The vehicle may contain a high proportion of ethanol or sucrose
together with antimicrobial preservatives
 But if the alcohol content > 12% v/v alcohol
No need of preservatives: due to the antimicrobial of alcohol
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Liquid dosage…

Linctuses
 Linctuses are viscous, liquid oral preparations that are usually
prescribed for the relief of cough
 Usually contain a high proportion of syrup and glycerol which
have a demulcent effect on the membranes of the throat
 The dose volume is small (5ml) and, to prolong the demulcent
action, they should be taken undiluted
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Liquid dosage…

Gargles
 They are aqueous solutions used in the prevention or treatment of
throat infections.
 Usually they are prepared in a concentrated solution with
directions for the patient to dilute with warm water before use.
Mouthwashes
 These are similar to gargles but are used for oral hygiene and to
treat infections of the mouth.
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Liquid dosage forms

Enema
 Enemas are pharmaceutical solutions that are administered in to
rectum and colon via the anus
Types of enema:
1- Evacuant enema: used as a bowel stimulant to treat
constipation. E.g. soft soap enema & Mgso4 enema
 The volume of evacuant enemas may reach up to 2 liters.
 They should be warmed to body T before administration.
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Liquid dosage forms

2- Retention enema:
- Their volume does not exceed 100 ml
- No warming needed
 The administration of substances into the bloodstream
 This may be done in situations where it is impossible to deliver a
medication by mouth, such as antiemetics
e.g. nutrient enema which contains carbohydrates, vitamins &
minerals.
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Liquid dosage forms

Oral emulsion:
 Oral emulsions are stabilized oil-in-water dispersions, either or
both phases of which may contain dissolved solids.
Oral suspension:
 They are liquid preparations for oral use containing one or more
active ingredients suspended in a suitable vehicle.
 They may show a sediment which is readily dispersed on shaking
to give a uniform suspension which remains sufficiently stable to
enable the correct dose to be delivered.
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Liquid dosage forms

Semisolid dosage forms
Ointments
 Ointments are semi-solid, greasy preparations for application
to the skin, rectum or nasal mucosa (semisolid suspension)
 Ointments form a transparent unbroken relatively water
impermeable film in the skin
 Ointments may be used as
 Effective barrier against moisture loss
 A vehicle to apply suspended or dissolved medicaments to the
skin
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Pastes
 Pastes are basically ointments into which a high percentage of
insoluble solid has been added
 Stiff: The extraordinary amount of particulate matter(ZnO)
 Like ointments, paste forms
 an unbroken relatively water impermeable opaque film
 therefore can be used as an effective sun block accordingly.
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Semisolid dosage…

Creams
Creams are semi-solid emulsions, that is mixtures of oil and water.
They are divided into two types:
A- Oil-in-water (O/W) creams: small droplets of oil dispersed in a continuous
aqueous phase.
 O/W are more comfortable and cosmetically acceptable as they are less
greasy more easily washed off using water.
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Semisolid dosage…
Oil- in-water

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B- Water-in-oil (W/O) creams: small droplets of water
dispersed in a continuous oily phase
Advantage: Release drug readily
More moisturizing
Disadv: More difficult to handle
Semisolid dosage…
Water-in-oil

Gels (Jellies)
 Pharmaceutical gels or jellies are SDF composed of a liquid phase
within a network structure of a solid gelling agent (consisting of
natural or synthetic gum or aluminium hydroxide)
 They are used for medication, lubrication and some miscellaneous
applications like carrier for spermicidal agents to be used intra
vaginally
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Semisolid dosage…

Lotions
 These are either liquid (aqueous) or semisolid preparations
containing one or more APIs used for external application without
friction.
 They are either dabbed on the skin or applied on a suitable
dressing and covered with a waterproof dressing to reduce
evaporation.
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Semisolid dosage…

Gaseous dosage forms
Pressurized dispensers (aerosol sprays)
 Several different types of pharmaceutical product may be
packaged in pressurized dispensers, known as aerosols.
 Sprays produce droplets of 100 um diameter or greater.
 May be used as surface disinfectants, wound or burn dressing,
relieve irritation of bites
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Inhaler :
 Inhalers are solutions, suspensions or emulsion of drugs in a mixture of inert
propellants held under pressure in an aerosol dispenser.
 Release of a dose of the medicament in the form of droplets of 50 um diameter
or less from the container through a spring-loaded valve incorporating a
metering device. The patient then inhales the released drug through a
mouthpiece.
 In some types, the valve is actuated by finger pressure, in other types the valve
is actuated by the patient breathing in through the mouthpiece.
 It is commonly used to treat asthma and other respiratory problems.
- Because they are
- cheaper
- more portable and
- carry less risk of side effects Doctors prefer
inhalers
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Gaseous dosage…

Objectives
 Describe the pharmacokinetic implications of various
routes of administration
 Understand the advantages and disadvantage of
various routes of administration
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Route of drug administration
 A route of administration in pharmacy is the path by which a
drug is taken into the body.
Classification
1. Systemic Route
2. Local route
In this route the drug is
applied on the skin and
mucous membrane for the
local action
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Oral Route (per oral)
 In this route the drug is placed in the mouth and swallowed
Advantages
 Convenient - Can be self-administered, painless, easy to take
 Cheap - not sterilization
 Variety – tablets, capsules, fast, slow release
Disadvantages
 May be inefficient - high dose, low solubility (only part of the drug may be
absorbed)
 Food Interaction: Tetracyclines and Penicillins
 Irritation to gastric mucosa – nausea and vomiting, Aspirin and NSAIDs
 Destruction of drugs by gastric acid and digestive juices: Erythromycin
 Unconscious patient - not able to swallow
 Unpleasant test of some drugs: Quinine
 First-pass effect
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Hepatic first pass effect
 The hepatic metabolism of a pharmacological agent when it
is absorbed from the gut and delivered to the liver via the
portal circulation.
 The greater the first-pass effect, the less the agent will reach
the systemic circulation when the agent is administered
orally
 Imipramine, Propranolol, Lidocaine
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Sublingual/Buccal route
 Drug is kept in the buccal cavity or under tongue where it
disintegrates and absorption occurs in the mouth
 Buccal -often harder – slower absorption
 4 hour disintegration (USP XX p 958)
 Sublingual - softer - faster release
 2 min disintegration (USP XX Nitroglycerin p552)
Examples - nitroglycerin, steriods, nicotine (chewing gum)
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Sublingual/Buccal route…
Advantages
 Avoid first pass effect: direct to the blood (liver is by-passed )
 Rapid absorption: good blood supply to the area
 Drug stability: not destroyed by the enzymes and acids
Disadvantages
 Inconvenient
 Holding the dose in the mouth
 Advantages lost if swallowed
 Small dose limit: Small size is required to keep the drug in the
mouth
 Unpleasant taste of some drugs
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Rectal Route
 By Suppository or Enema
E.g. aspirin, theophylline, chlorpromazine
Advantages
 By pass liver: Following absorption from the rectum, the therapeutic agent
enters the haemorrhoidal veins.
 Blood from the upper haemorrhoidal vein enters the portal vein,
 Blood in the middle and lower haemorrhoidal veins enters the general
circulation.
 Useful - children, non po
 If patient is having nauseous or vomiting
Disadvantages
 Erratic absorption
 Not well accepted
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Parenteral: Intravenous
 Injection into a peripheral vein over 1 to 2 minutes (bolus)
or longer as an infusion
Advantages
 Rapid response, Total dose ►by-passes absorption stage
 larger doses by infusion
 Can be given to unconscious patients
Disadvantages
 Suitable vein, Trained personnel
 Greater risk of adverse effects
 Expensive - sterility, solvent, transport
 Pain at the site of injection
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Intramuscular
Advantages
 Larger volume than SC
 Depot or sustained effect is
possible
Disadvantages
 Trained personnel
 Site affects absorption: deltoid
 Absorption may be erratic or
incomplete
• In this route of administration the drug is given
into the muscles with the help of injection
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Subcutaneous
 In this route of administration the drug is given into the
subcutaneous layer with the help of injection(Just
under the skin)
Advantages
 Can be given by the patient e.g. in the case of insulin
 Absorption slow but generally complete
 Massage or heat, Vasoconstriction
Disadvantages
 Painful
 Tissue damage from irritant drugs
 Maximum of 2 ml injection
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Inhalation
 In this class the drug is administered
 To the blood without going to the GIT
 Not administered with the help of injections
 Local effect: bronchodilator
 Systemic effect: general anesthesia
Advantages
 By pass liver
 Absorption of gases efficient and rapid
Disadvantage
 Solids and liquids excluded if > 20 mincron and exhaled if < 0.5
micron
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Local/Topical route of drug administration
 In this route the drug is applied on the skin and mucous
membrane for the local action
 Dermal - Rubbing in of oil or ointment (local effect)
 eg eye drops, antiseptic, sunscreen
 Transdermal - Absorption of drug through skin (systemic
effect)
 e.g. nitroglycerine ointment, scopolamine
Advantage
 Stable blood levels
 No first pass metabolism
Disadvantage
 Toxicity from topical absorption
 Burn patients
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Other ROA’s
 Intra-nasal - small dose, avoid first pass
 Intra-arterial - cancer chemotherapy, localised delivery
 Intraosseous route- in to bone marrow
 Others routes with limited systemic absorption but
with local utility include
 Ocular
 Aural
 Vaginal
 Urethral
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Other….
 Intra-thecal - into
the cerebrospinal
fluid, avoid BBB
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Onset of Action
 Intravenous 30-60 seconds
 Intraosseous 30-60 seconds
 Inhalation 2-3 minutes
 Sublingual 3-5 minutes
 Intramuscular 10-20 minutes
 Subcutaneous 15-30 minutes
 Rectal 5-30 minutes
 Oral 30-90 minutes
 Topical/transdermal (topical): variable
(minutes to hours)
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