Transcript Pharmaceutical Dosage Forms

Pharmaceutical Dosage Forms-1
Lecture 1: Introduction
Pharmaceutics
• Pharmaceutics is the science of dosage form
design.
• There are many chemicals with known
pharmacological properties but a raw
chemical is of no use to a patient.
• Pharmaceutics deals with the formulation of a
pure drug substance into a dosage form
Active Drug Substance
• (Active pharmaceutical ingredient - API)
• Chemical compound with pharmacological (or other
direct effect ) intended for use in diagnosis, treatment
or prophylaxis of diseases.
• International non-proprietary names (INN, generic
names)
Drug names
• A chemical name - the scientific name of the drug
chemical. This is mainly used by researchers, but is
sometimes shortened and used by health workers instead
of the generic or brand name.
• A generic name - the name that is adapted from the
chemical name and is shorter and easier to say. This is
usually decided by the World Health Organization and is
also called the international non-proprietary name (INN).
• A brand or proprietary name - the name chosen by the
producer of the drug. This is short and easy to remember,
to encourage people to ask for the drug by that name.
API is not use as such. Why???
• 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
• Some API can benefit from reducing the
exposure to the environmental factors (light,
moisture…), or they need to be chemically
stabilised due to the inherent chemical
instability
API is not use as such. Why???
• API can be degraded at the site of
administration (e.g., low pH in stomach)
• 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!)
• Administration of active substance would
mean to have no chance for modification
(improvement) of its PK profile
From drug substance to
pharmaceutical preparation
• Besides the choice of the active drug
substance, you need to also make a
responsible decision regarding the route of
administration and the DOSAGE FORM (drug
delivery system) – wrong choice can cause
failure of therapy
• You should also be able to handle and
administer the drug properly or advise the
patient about it – wrong use can cause failure
of therapy
Excipients (Additives)
• Excipients (inactive pharmaceutical
ingredients)
– Its selection depends on technological,
biopharmaceutical and/or stability reasons.
– Diluents/fillers, binders, lubricants, coatings,
preservatives, colorants and flavouring agents
Pharmaceutical dosage form
• Pharmaceutical dosage form
– Determines the physical form of the final
pharmaceutical preparation
– Is a drug delivery system which is formed by
technological processing (drug formulation)
– Must reflect therapeutic intentions, route of
administrations, dosing etc.
Pharmaceutical preparation (PP)
• Pharmaceutical preparation (PP)
– particular pharmaceutical product containing
active and inactive pharmaceutical ingredients
formulated into the particular dosage form.
– Packed and labelled appropriately
– Two major types of PP according the origin:
• Manufactured in large scales by pharmaceutical
industry (original and generic preparations)
• Compounded individually in compounding pharmacies
(Extemporaneous Preparations)
1- Pharmaceutical preparations
manufactured by pharmaceutical industry
1.1- Original pharmaceutical preparations
– undergo full and very extensive pharmacological/
toxicological and pharmaceutical pre-clinical and
clinical development and evaluation
– particularly important is the proof of effectiveness
and safety
1.2- Generic pharmaceutical preparations („authorised copies of
original preparations“)
-Can be released after the expiration of the patent
protection of the original preparation
– The approval for clinical use is easier due to the
prior experience with the original preparation
– Must be pharmaceutically equivalent: same API,
dose, pharmaceutical dosage form and the same
route of administration as in original preparation
– Must be clinically bioequivalent: i.e. it must be of
very close PK profile as original preparation. PK
parameters (Cmax, tmax, AUC) are within 80-125
% range as compared with the original
preparation.
2- Extemporaneous Preparations
• These PP are compounded individually for a
particular patient according to the physician's
prescription in a pharmacy licensed for
compounding
Extemporaneous Preparations Can be
Used When:
• The drug in a particular dosage form is not
commercially available on the market
• The extraordinary low or high dose is needed (young
children, elderly people, special situations – e.g.,
intoxications). In this case right dosage strength need
not be readily commercially available for every patient
• The patient suffers from the allergy on a specific
excipients (e.g., lactose – a filler, some
colorizing/flavouring or antimicrobial agents parabens) or another drug appearing in the PP
• Patient is unable to use a PP in its commercially
available dosage form (e.g., children, elderly)
Classification of pharmaceutical dosage forms
according to physical properties
– Gaseous dosage forms
– Liquid dosage forms
– Semisolid dosage forms
– Solid dosage forms
Gases
• Medicinal gases, inhalation/volatile
anaesthetics
• Aerodispersions of solid particles (e.g.,
antiasthmatic inhalations) or liquid particles
(antiasthmatic inhalations or sprays)
Liquids
• Solutions
One homogenous phase, prepared by dissolving one or more
solutes in a solvent
• Emulsions
• a dispersion system consisting of two immiscible liquids
• o/w or w/o
• cloudy appearance
• Suspensions
• A dispersion system where solid particles (dispersed
phase) are dispersed in liquid phase (dispersion
medium)
Semisolid dosage forms
1- Unshaped (without specific physical shape)
• Gels -A semisolid systems in which a
liquid phase is constrained within a
3D cross-linked matrix.
• Creams – semisolid emulsion
systems (o/w, w/o) containing more
than 10% of water.
Semisolid dosage forms
1- Unshaped (without specific physical shape)
• Ointments – semisolid dosage forms with the
oleaginous (hydrocarbon), water-soluble or emulsifying
base
• Pastes – semisolid dispersion system, where a solid
particles (> 25%, e.g. ZnO) are dispersed in ointments –
mostly oleaginous (Petrolatum)
Semisolid dosage forms
2- Shaped
• Suppositories (for rectal administration)
–different shapes
–Melting/dissolving at body temperature
–Oleaginous (cacao butter) or aqueous (PEGs,
glycerinated gelatine)
• Pessaries (vaginal suppositories)
–Similar as above, PEGs or glycerinated
gelatine are often used as base.
Solid Dosage Forms
– Unshaped (without specific shape)
- powders for external/internal use
– Shaped
- Tablets
- Capsules
- Implants (Sterile disks inserted surgically into body
tissues and designed to release drug(s) over extended
period of time)
- Transdermal patches
- Lozenges (consists of sugar and gum to medicate the
mouth and throate)
Classification of pharmaceutical dosage forms
according to the route of administration
1) For systemic administration
• Peroral (p.o)
• Sublingual (S.L) and buccal.
• Rectal
• Parenteral
• Transdermal
• Inhalation
Classification of pharmaceutical dosage forms
according to the route of administration
2) For local administration
• Topical (on the skin or mucosa)
Into/onto - the eye, nose, ear
- the oral cavity
- the vagina, rectum
- the bronchi
- the skin
• Local parenteral (viz Parenteral above)
• Oral (local effect within GIT; antacids, adsorbents)
Types of Drugs
• Legend Drugs: These drugs may not be
dispensed by a pharmacist without a
prescription from a physician.
• Controlled Drugs: In addition to requiring a
prescription, these drugs require additional
safeguards for storage. Refills are also limited.
• Over-the-Counter (OTC) Drugs: These drugs
do not require a prescription.