Concept of medicine and dosage forms, brands and generics Flashcards
Drug
Also known as Active Pharmaceutical Ingredient (API)
Excipient
All the other components of a formulation other than the active drug
Each component requires an appropriate evaluation for safety.
An excipient should be chemically and physiologically inert.
People may have moral or religious problems with excipients e.g. Gelatin
Formulation
The process in which APIs and excipients are combined to produce a medicinal product
Every branded medication has 2 names
The Brand name: Given by the pharmaceutical R&D company and is a registered ® name.
Chemical name – name for the active pharmaceutical ingredient, which is decided by an expert committee
trademark
is any word, name, symbol, or design, or any combination thereof, used in commerce to identify and distinguish the goods of one manufacturer or seller from those of another and to indicate the source of the goods
Branded Drugs
New medicines are marketed as a branded product.
Companies take out patents on each new drug they discover to regain money spent on R&D and make a profit.
A standard patent last 20 years but can be extended by an additional 5 years.
It takes approx. 10-15years of this period to develop, file a new drug application and obtain a marketing authorization (MA).
Only the company can produce and sell the medicine to recover costs during the remaining years
Pharmaceutical Research & Development (R&D) Industry
The objective of pharmaceutical research and development is to “convert synthesised chemical compounds into candidate drugs for development”
Product development involves “converting candidate drugs into dosage forms for registration and sale”
Generic Drug Companies
Generic business kicks in when a leading brand finally loses patent protection.
Usually, a multiple of generic drug companies launch copycat versions of the original.
Profits are much lower.
Generics can become blockbusters!
Loathed by the Pharma R&D
Loved by Health Ministers
Pharma R&D have introduced lifecycle management to increase patent protection
What is a Generic Drug?
A drug which is bioequivalent (PK and PD properties) to a leading brand name
Generic medicines must be identical
in dose, route of administration,
safety and efficacy as the “innovator”
Interchangeable with the branded
drug at the pharmacy
A generic name is used for the
medicine (typically chemical name).
chemical generic
can be copied quickly and are inexpensive
2-3
years
lower up-font investment greater savings
biosimilars
complex biologics take longer and cost more to duplicate
more time and more investment
Prescribing generic medicines
Prescribers are encouraged to prescribe medicines by their generic name.
Generic medicines are equally effective and can save up to 80% on the cost of a branded product
Allow pharmacist the widest choice of products to dispense.
Important if there is a shortage of a particular product
Word of Caution
In rare cases, a patient may need to stay on a branded medicine.
Some examples may include:
Epilepsy medicines – slight differences in rate of absorption may cause a big difference in therapeutic effect.
Modified-release preparations – Generic equivalents may absorb differently.
Lithium – different brands may vary widely in the absorption and how the medicine becomes active.
Biological medicines – Copies of these complex medicines (called biosimilars) may not be automatically used as a substitute. Doctors need to reference the specific manufacturer
Dosage forms
Dosage forms are the means by which drug molecules are delivered to sites of action within the body
What do we need in a dosage form:
Accurate dosing
Protection and Shelf-life
Protection from gastric juice
Masking taste and odour
Placement of drugs directly within body tissues
Sustained release medication.
Controlled release medication.
Insertion of drugs into body cavities
Use of desired vehicle for insoluble drugs
Uses for excipients
Aid processing of the system during manufacture and accurate dose control
Control rate of absorption
Protect, support or enhance stability, bioavailability or acceptability
Assist in product identification
Enhance any other attribute of the overall safety and effectiveness of the drug product during storage and use
Why are Ibuprofen tablets film coated?
Avoiding gastric mucosal irritation- peptic and mucosal ulcers, dyspepsia, severe gastric pain and bleeding
Taste
Very subjective and difficult to quantify
Many drugs extremely bitter
Can be mitigated by film-coating
Solid oral dosage forms: Tablet/Caplet
A tablet is a hard, compressed medication in round, oval or square shape.
Excipients include
Diluents (Compressible bulking agents), binders, glidants (flow aids) and dry lubricants to ensure efficient tabletting.
Disintegrants to ensure that the tablet breaks up in the GI tract.
Sweeteners or film coatings for taste masking active pharmaceutical ingredients
90 % of medicines are taken orally
Requirements for an ideal oral solid dosage form:
drug must remain stable
drug must be bioavailable (formulation reliably releases drug in GIT)
uniform drug content (reproducible dose)
robust and resistant to disintegration during handling
easy and cost effective to mass produce
pleasant to take
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.
Bypasses the stomach and liver
Effervescent Tablet
Effervescent tablets are uncoated tablets that generally contain acid substances (citric and tartaric acids) and bicarbonates and which react rapidly in the presence of water to effervesce by releasing carbon dioxide.
They are intended to be dissolved or dispersed in water before use providing:
Very rapid tablet dispersion and dissolution.
Pleasant tasting carbonated drink by addition of sodium saccharin (sweetener)
Lubricants need to be water soluble
Tablet packaging is critical for stability
Capsule
A capsule is a dosage form in which a formulation is contained in a gelatin or a Hydroxypropyl methylcellulose matrix.
Advantage: mask the unpleasant taste of its contents.
The two main types of capsules are:
Hard-shelled capsules, which are normally used for dry, powdered ingredients,
Soft-shelled capsules, primarily used for oils and for active ingredients that are dissolved or suspended in oils or emulsions
Oral Granules
Consist 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
Fast Dissolving Oral Delivery Formulations
Solid dosage form that dissolves or disintegrates rapidly in oral cavity, resulting in solution or suspension without the need of water Also known as: Orodispersible tablets, melts
Tablet disperses in saliva
for some drugs a portion may be absorbed from the mouth, pharynx and oesophagus as the saliva passes towards the stomach (potentially increased absorption/bioavailability)
formulations are either very porous or soft moulded matrices or compressed into tablets with very
low compression force
Tablets difficult to handle - often require specialized
‘peel-off blister’ packaging
Solutions
Oral solutions are clear liquid preparations for oral use
containing one or more APIs dissolved in a solvent. Solvents include diluted alcohol, glycerin or propylene glycol and purified water
Emulsions
Emulsions
Oral emulsions are stabilized oil-in-water dispersions,
either or both phases of which may contain dissolved solids
Suspensions
Suspensions
Oral suspensions are liquid preparations for oral use containing one or more APIs suspended in a suitable vehicle.
Liquid vehicles include purified water with cellulose derivative polymers and thickening agents (e.g. Xanthan Gum)
Syrup
It is a concentrated aqueous solution of a sugar.
Flavored syrups are a convenient form of masking disagreeable tastes
Elixir
It is pleasantly flavored clear liquid oral preparation of potent or nauseous drugs.
The vehicle may contain a high proportion of ethanol in purified water and sucrose together with antimicrobial preservatives which confers the stability of the preparation
Linctus
Linctuses are viscous, liquid oral preparations that are usually prescribed for the relief of cough.
They usually contain a high proportion of syrup and glycerol which have a demulcent effect on the membranes of the throat.
The dose volume is typically small
Oral drops
Oral drops are liquid preparations for oral use that are
intended to be administered in small volumes with the aid of a suitable measuring device. They may be solutions, suspensions or emulsions
topical dosage forms- ointments
Ointments are viscous, semi-solid, greasy preparations (oil 80% to 20% water) for application to the skin, rectum or nasal mucosa.
The base is usually anhydrous and immiscible with skin secretions.
Ointments may be used as emollients or to apply suspended or dissolved medicaments to the skin
Topical dosage forms: Creams
Creams are semi-solid emulsions, that is mixtures of oil and water. They are divided into two types:
Oil-in-water (O/W) creams: O/W are more comfortable and cosmetically acceptable as they are less greasy and more easily washed off using water.
Water-in-oil (W/O) creams: W/O creams more difficult to handle but many drugs which are incorporated into creams are hydrophobic and will be released more readily from a water-in-oil cream than an oil-in-water cream.
Water-in-oil creams are also more moisturising as they provide an oily barrier which reduces water loss from the stratum corneum
Topical dosage forms: Gels
Gels are semisolid system in which a liquid phase is constrained within a 3D polymeric matrix (consisting of natural or synthetic polymer) having a high degree of physical or chemical cross-linking.
They are used for medication, lubrication and some miscellaneous applications like carrier for spermicidal agents to be used intra vaginally
Transdermal dosage forms: Patch
A transdermal patch or skin patch is a medicated adhesive patch that is placed on the skin to deliver a specific dose of medication through the skin and into the bloodstream.
An advantage of a transdermal drug delivery route over other types such as oral, topical, etc is that it provides a controlled release of the medicament into the patient.
The first commercially available patch
was scopolamine
for motion sickness
Rectal/Vaginal dosage forms: Suppositories/Pessaries
Suppositories are solid dosage forms intended for administration of medicine via the rectum, vagina (pessaries) or urethra (bougies) that melt, soften or dissolve in the body cavity.
Suppositories are made by dissolving or dispersing the active ingredient(s) in a base at an elevated temperature, the mix is then poured into a mould and solidifies at room temperature.
The quantity of fluid available for drug dissolution in the rectum is very small - approximately 3 ml and 100mm thick layer.
Parenteral dosage forms
An injection is an infusion method of putting liquid into the body, usually with a hollow needle and a syringe which is pierced through the skin to a sufficient depth for the material to be forced into the body.
Intravenous (IV) injection
It is a liquid administered directly into the bloodstream via a vein.
It is advantageous when a rapid onset of action is needed.
100% of drug is bioavailable
Intramuscular injection
It is the injection of a substance directly into a muscle.
Many vaccines are administered intramuscularly.
Depending on the chemical properties of the drug, the medication may either be absorbed fairly quickly or more gradually.
Injection sites include the deltoid muscle of the arm, the vastus lateralis of the leg and the gluteal muscles of the buttocks
Subcutaneous injections are given by injecting a fluid into the subcutis, the layer of fatty tissue directly below the dermis and epidermis.
Subcutaneous injections are highly effective in administering vaccines and such medications as insulin
Inhaled dosage forms
Inhaled drug delivery is any drug or solution of drug administered by the nasal or oral respiratory tract
Inhalers are prepared either as solutions, suspensions or a dry powder formulation.
There is a need to deliver the drug in an
aerosol form (less than 5µm)
Ophthalmic dosage forms
Eye drops are saline-containing drops used as a vehicle to administer medication in the eye.
Depending on the condition being treated, they may contain steroids, antihistamines or topical anesthetics.
Eye drops sometimes do not have medications in them and are only lubricating and tear-replacing solutions.
Ophthalmic ointments
These are sterile semi-solid preparations intended for application to the conjunctiva or eyelid margin.
