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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_5724_Библиотеки_им_академика_М_И_Перельмана.pdf
215
Dosage Forms
R
x
Soft soap 3.75 gm
Camphor 2.50 gm
Turpentine oil 32.50 ml
Purified water 11.25 ml
Make: Liniment.
Direction: To be applied externally to the affected part with
friction.
Type: Emulsion type liniment made with an alkali soap.
Procedure
Dissolve the camphor in turpentine oil in a dry container.
Separately dissolve soft soap in small amount of purified water
in a mortar. To this gradually add the camphor solution with
thorough trituration after each addition until a thick creamy
emulsion is formed. Add sufficient purified water to produce
the required volume. Transfer the preparation to a bottle, label
and dispense. Apply the secondary label “For external use
only” and “Shake the bottle before use.”
Uses
It acts as an irritant, counter-irritant and rubefacient.
Liniment of turpentine is applied externally to the patients
suffering from arthralgia (pain in the joints), myalgia (muscular
pain), fibrositis (ligamental pain) and sprain.
Irritants are the agents or substances· which do not directly
destroy the tissues but cause inflammation in the area to
which they are applied.
Rubefacients are the substances which produce congestion
and redness of the area to which they are applied, producing
the initial symptoms of irritation.
Counter-irritants are the agents or drugs which are applied
locally to irritate the intact skin thus ·reducing or relieving
another irritation or deep seated pain. They seem to work
by producing an inflammation, thus increasing the flow of
blood to the affected area. Physical counter-irritants include
hot water bottles, radiant heat, short wave diathenny and
Introduction to Pharmaceutics
216
galvanic electric current. Chemical counter-irritants include
volatile substances like turpentine oil, camphor, menthol,
thymol and methyl salicylate.
Since turpentine oil is a volatile oil which is not miscible
with water, to make them miscible with each other soft
soap has been used which acts as an emulsifying agent.
Turpentine oil is a volatile oil obtained by the distillation,
and rectification of turpentine which is an oleoresin
obtained from various species of pinus.
Camphor is a volatile substance obtained from wood of
cinnamomum camphora. It can be prepared synthetically.
Externally it acts as a mild analgesic and rubefacient. It is
used as a counter-irritant in the treatment of fibrositis and
neuralgia.
Precautions
Liniments are not to be applied to the broken skin because they
may produce excessive irritation of the skin.
LOTIONS
Lotions are usually suspensions or dispersions intended for
external application to the skin. They are applied directly to
the skin without rubbing with the help of some absorbent
material such as cotton wool or the cotton wool or gauze
soaked in the lotion is applied to the affected part. Lotions may
be employed for local cooling, soothing or protective purposes.
Dermatologists frequently prescribe lotions for anaesthetic or
antiseptic actions. The inclusion of alcohol in a lotion hastens
its drying and produces cooling effect whereas the addition of
glycerin in a lotion keeps the skin moist for sufficiently long
time and does not allow the preparation to dry.
Bacteria and molds grow in certain lotions if no preservative
is added to the preparation. Even if a preservative is added
care must be taken to avoid contamination during preparation
of the lotion.
Lotions should be dispensed in coloured fluted bottles
in order to distinguish from preparations meant for internal
use. The container should be labelled “For external use only.”
217
Dosage Forms
On long standing the lotions have a tendency to separate out.
Therefore, the container must be labelled “Shake before use.”
Examples are calamine lotion, oily calamine lotion, salicylic
acid lotion and zinc sulphate lotion.
Lotions Containing Insoluble Substances
When a lotion contains insoluble substances of indiffusible
nature, it will have to be dispensed in lotions like that of
mixtures, i.e., by incorporating a suspending agent. For this
purpose gummy suspending agents like tragacanth is not
suitable because of their sticky nature. Therefore, bentonite and
aluminium hydroxide gel are sometimes used as suspending
agents.
Calamine lotion is the best example of lotions containing
insoluble substances. This lotion contains calamine, zinc oxide,
bentonite, sodium citrate, liquefied phenol, glycerin and
purified water.
Here calamine is an insoluble substance of indiffusible
nature. It acts as astringent, soothing and protective agent.
Zinc oxide is an adjuvant, it acts as mild astringent with local
soothing, protective and antiseptic properties. Bentonite acts
as a suspending agent which swells up in water and imparts
viscosity to the solution. Sodium citrate is incorporated to
prevent the lotion from being too viscous. Liquefied phenol is
used as an antiseptic and glycerin as a humectant.
Method of Preparation
Triturate calamine, zinc oxide and bentonite with a portion
of sodium citrate solution in a mortar till a smooth cream is
formed. Add remaining amount of sodium citrate solution
and mix well. Incorporate glycerin and liquefied phenol, mix
thoroughly. Add more of vehicle to produce the required
volume. Stir thoroughly so as to get a homogeneous product.
R
x
Calamine 15.0 gm
Zinc oxide 5.0 gm
Bentonite 3.0 gm
Introduction to Pharmaceutics
218
Sodium citrate 0.5 gm
Liquefied phenol 0.5 ml
Glycerin 5.0 ml
Purified water up to 100.0 ml
Make: Lotion. Send 50 ml.
Direction: To be applied to the affected part of the skin
without friction.
Calamine is basic zinc carbonate mixed with suitable
amount of ferric oxide to impart pink colour. It is often
prescribed by dermatologists to give flesh like colour to
lotions or creams.
Zinc oxide has mild astringent, protective and antiseptic
action. It is widely used in dusting powders, lotion, and
ointments meant for the treatment of skin diseases and
infections such as eczema, ringworm, psoriasis (chronic
skin disease in which red scaly patches develop) and
pruritus (itching).
Bentonite is a native colloidal hydrated aluminium silicate.
It is insoluble in water but swells up nearly seven times its
bulk and forms a magma with desirable viscosity. Hence, it
is used as suspending agent for the dispersion of insoluble
substances like calamine, etc.
Sodium citrate is added to prevent the lotion from being too
viscous. It acts as a buffer and maintains the pH appropriate
for skin preparations.
Liquefied phenol acts as antipruritic because of its antiseptic
properties and also because of its local anaesthetic action.
Glycerin acts as a hygroscopic thus keeps the skin moist
and have soothening effect on the skin.
Procedure
Mix the weighed amount of calamine, zinc oxide and bentonite
in a mortar. Triturate it with a solution of sodium citrate in
about 70 ml of purified water. Add the required quantity of
liquefied phenol and glycerin. Mix well. To this add more of
vehicle to produce the required volume. Mix thoroughly so as
to get a uniform preparation. Transfer to a bottle, cork, label
219
Dosage Forms
and dispense. Apply the secondary label “Shake the bottle
before use” and “For external use only”.
Uses
This lotion is used as an astringent and protectant from
sunburn. It acts as a soothening agent and gives relief from
itching and pain during skin irritation. It is also used in
ringworm infection and eczema.
OTHER PREPARATIONS
NASAL PREPARATIONS
Nasal preparations are products used in the nose to treat nasal
conditions or symptoms. They include medicines like nasal
steroids, lubricants, antihistamines, decongestants, and anti-
infectives. These are commonly used in case of fever symptoms,
congestion, and infections. Nasal preparations come in various
forms such as sprays, drops, creams, ointments, and solutions
for irrigation.
The nasal cavity begins at the nostrils, which guide air
into the nose. Inside, there are structures like the turbinates
and nasal epithelium, followed by the nasopharynx where
the nasal cavity becomes one. The nasal mucosa, lined with
ciliated cells, mucous glands, and goblet cells, plays a vital role
in producing and storing nasal mucus.
Advantages
1. Rapid onset of action: Nasal mucosa has a rich blood
supply, allowing drugs to be rapidly absorbed into systemic
circulation, leading to quick onset of action compared to
oral administration.
2. Avoidance of first-pass metabolism: By bypassing the
gastrointestinal tract and liver, nasal drug delivery can avoid
first-pass metabolism, leading to higher bioavailability for
certain drugs.
3. Non-invasive route: Nasal drug delivery is non-invasive
and relatively easy to administer, making it suitable for
Introduction to Pharmaceutics
220
patients who have difficulty swallowing or are unable to
take oral medications.
4. Enhanced patient compliance: Nasal sprays and drops
are often preferred by patients due to their ease of use
and convenience, leading to improved compliance with
medication regimens.
5. Targeted delivery to the upper respiratory tract: Nasal
drug delivery allows for targeted delivery of medications
to the nasal cavity and upper respiratory tract, making it
effective for treating conditions such as allergic rhinitis,
sinusitis, and nasal congestion.
6. Reduced systemic side effects: By delivering drugs directly
to the site of action in the nasal cavity, nasal drug delivery
can minimize systemic side effects associated with systemic
administration of drugs.
7. Potential for brain delivery: The olfactory region of the
nasal cavity provides a direct pathway to the central
nervous system, allowing for direct delivery of drugs to the
brain, which can be advantageous for treating neurological
disorder offering quick action, various delivery options,
and high acceptance. However, it has limitations regarding
volume and compatibility with certain drug types.
Disadvantages
1. Limited absorption surface: The nasal cavity provides
a relatively small absorption surface compared to other
routes of administration, which may limit the absorption
and bioavailability of certain drugs.
2. Mucociliary clearance: The mucociliary clearance
mechanism in the nasal cavity can remove drug particles,
reducing their residence time and absorption. This clearance
mechanism can limit the effectiveness of nasal drug
delivery, especially for drugs with poor mucosal adhesion.
3. Nasal congestion: Nasal congestion or blockage can hinder
drug deposition and absorption in the nasal cavity, affecting
the efficacy of nasal drug delivery systems. Patients with
nasal congestion may experience reduced drug delivery
and efficacy.
221
Dosage Forms
4. Variable absorption: Nasal drug absorption can be
variable and unpredictable due to factors such as nasal
mucosal permeability, nasal pH, and individual anatomical
differences. This variability may lead to inconsistent
drug levels in the bloodstream and variable therapeutic
responses.
5. Irritation and sensation: Some patients may experience
irritation, stinging, or burning sensations in the nasal cavity
when using nasal drug delivery systems, which can affect
patient compliance and acceptance of treatment.
6. Volume limitations: Nasal drug delivery devices, such as
nasal sprays and drops, have limited volume capacities,
which may restrict the delivery of certain medications or
formulations requiring larger doses.
7. Nasal discomfort: Prolonged or frequent use of nasal
drug delivery systems may cause discomfort or dryness
in the nasal cavity, leading to nasal irritation, bleeding, or
ulceration in some cases.
8. Systemic absorption and side effects: Despite bypassing
first-pass metabolism, nasal drug delivery can still result
in systemic absorption of drugs, leading to systemic side
effects or adverse reactions in some patients.
9. Contamination risk: Improper handling or storage of
nasal drug delivery devices may increase the risk of
contamination, leading to microbial growth or infection in
the nasal cavity.
Liquid Nasal Formulations
These are commonly used for nasal administration and
help humidify the nasal passages, beneficial for allergic and
chronic conditions that cause crusts and drying of the mucous
membrane.
Types
a. Instillation and rhinyle catheter: A catheter is used to
deliver drops to specific areas of the nasal cavity. For the
delivery of dosage forms, place one end of the tube in the
nose and deliver the solution by blowing through the other
end with the mouth.
Introduction to Pharmaceutics
222
b. Squeezed bottle: Typically used for decongestants. For
the delivery of dosage forms, press the plastic bottle to
release air through the small nozzle; releasing the pressure
draws air back into the bottle. Not recommended for the
children.
c. Metered-dose pump sprays: These nasal sprays deliver
medication in a specific amount. The accuracy of the dose
depends on the surface tension and viscosity of the container.
Common types include antihistamines, corticosteroids, and
topical decongestants for local effects.
Powder Dosage Forms for Nasal Administration
Less commonly used in nasal drug delivery but provide
prolonged contact with the nasal mucosa. They require fewer
preservatives and offer good stability.
Types
1. Insufflators: These deliver extremely small, fine solid
particles of pharmaceutical powder into the nasal cavity.
They consist of a tube containing the drug substance,
sometimes with a syringe.
2. Dry powder inhaler: Used to deliver dry powder for local
or systemic effects in the nasal route. These are used to treats
conditions like asthma, bronchitis, COPD, and diabetes
mellitus. The dose delivered must be less than a few tens of
milligrams in a single breath.
3. Pressurized MDIs (metered-dose inhalers): Widely used
for treating asthma, COPD, and other respiratory tract
disorders. They deliver medication through the mouth and
into the lungs. MDIs are portable, small-sized, and offer a
wide dosage range.
EAR PREPARATIONS
Ear preparations refer to pharmaceutical formulations speci-
fically designed for administration into the ear canal. These
preparations come in various forms, including solutions,
suspensions, emulsions, and ointments. They are intended
223
Dosage Forms
for the treatment of various ear conditions, such as infections,
inflammation, wax buildup, and otic discomfort.
The significance of ear preparations lies in their ability to
deliver medications directly to the ear canal, targeting the site
of the problem effectively. Unlike systemic medications, which
may have limited penetration into the ear, ear preparations
provide localized treatment, resulting in faster relief and
reduced systemic side effects.
The ear preparations are typically prepared using water,
glycerin, propylene glycol, or alcohol. Vehicles like glycerin
and propylene glycol are preferred as they increase contact
time and soften ear wax.
Merits (Advantages)
1. Targeted treatment directly to the ear canal.
2. Rapid relief of symptoms.
3. Reduced systemic side effects.
4. Patient comfort during administration.
5. Versatile formulations available.
Demerits (Disadvantages)
1. Risk of irritation or allergic reactions.
2. Potential for contamination if not handled properly.
3. Limited accessibility for some patients.
4. Difficulty in accurate application, especially for certain
populations.
5. Potential for tympanic membrane damage if administered
incorrectly.
Formulation of Ear Preparations
Ear Drops
Ear drops are liquid medications applied inside the ear canal
to treat pain, inflammation, infection, and earwax blockage.
They may contain glycerin, mineral oil, saline solutions, and
additional substances like carbamide peroxide, baking soda,
or acetic acid. Examples include Ciproxin HC
®
, Sofradex
®
, and
Locacorten-Vioform
®
.
Introduction to Pharmaceutics
224
Uses
Antibacterial properties.
Softening ear wax.
Treating mild infections.
Storage
Ear drops should be packed in colored, fluted glass bottles and
supplied with a dropper.
Labeling
“For external use only”
“Not for injection”
“Discontinue use if irritation persists”
Ear Spray
Ear spray formulations are intended for instillation into the
ear to treat various ear-related conditions. They often contain
active ingredients like Polysorbate 80 and chamomile.
Method to Use Ear Spray
Shake the bottle or spray, remove the top, and gently pull
the earlobe backwards to open the ear canal. Administer the
prescribed number of drops or spray into the ear canal.
Uses of Ear Spray
Ear spray is used to treat inflammation and infections of the
outer ear.
Storage
Once opened, ear spray typically has an expiry of four weeks.
It should not be stored beyond this expiry period.
POWDERS AND GRANULES
Powders are the solid dosage form of medicament which are
meant for internal and external use. They are available in