Ocular drug delivery system group b

1. Faculty of pharmacy
Hamdard university
DOSAGE LAB ASSIGNMENT CODE: pharm-406
2ND Professional (4th Semester) Morning-2019
SUBJECT: Pharmaceutics-IIB (Dosage Form Science) – Lab
ASSIGNMENT TOPIC
Submitted to Dr. Tahmina Adnan
Prepared by
o SYED MEHAR ALI SHAH (R-090) o SAIRA KALEEM (R-075)
o SHAMAIMA IRFAN (R-82) o M.SALEEM (R-48)
o SADIA PARVEEN (R-073)

2. These are the type of pharmaceutical preparations which are applied
topically to the eye to treat surface or intraocular
conditions.
It may be bacterial, fungal or viral infection of
eyelid or any infectious conjunctivitis or
inflammation; elevated intraocular pressure and
glaucoma; and dry eye due to inadequate
production of fluids bathing the eye. In treating
certain ophthalmic conditions , such as glaucoma,
both systemic drug use and topical treatments may be employed.

3. Classification of Ocular drug delivery system

4. Liquids
Solution:
 Ophthalmic solutions contain active ingredients that are
completely soluble in the liquid vehicle.
 Advantage: In this type of dosage form dose uniformity is
ensured and the application of the drug typically does not cause
blurry vision
 Disadvantage: there is a little contact time between the drug
and the cornea before the solution in drained away which can
lead to low levels of absorption.

5. Suspension:
Ophthalmic suspensions consist of particles of insoluble drug in
an aqueous vehicle that also contains suspending agents. To be
absorbed, the particles must dissolve sufficiently during the
residence time on the eye which makes the intrinsic solubility of
the drug an important factor to consider.
In order to ensure dose uniformity, patients should be counseled to
shake the formulation each time before administration, as settling of the
drug particles may occur. Particle size of the suspended drug particles is
of critical importance due to the potential for irritation and drug
dissolution.

6. Semisolids
Ointments:
Ophthalmic ointments may consist of drug incorporated
into mineral oil and white petrolatum base. Since the
ointment base is anhydrous, it can be used to carry
moisture-sensitive medication.
 Advantage: The ointment stays in place after
application, and this longer contact time results in greater
bioavailability.
 Disadvantage: the time to onset of action may be
slower. The application of the ointment will cause blurry
vision.

7. Gels:
Ophthalmic gels contain polymers, such as carbomer, that
form an aqueous semisolid dosage form that is applied to
the eye in a similar manner to an ointment. In some
cases, ophthalmic gels are formulated as a solution in
which included polymers form a gel upon contact with
tear fluid.
 Advantage: ophthalmic gels are that they provide
increased contact time with the eye tissue before
clearance and thus increased drug absorbance and
prolonged duration of therapeutic effect.
 Disadvantage: gels are that they can cause blurring of
vision.

8. Solids
Ocular insert:
Lacrisert
Lacrisert is a rod-shaped water- soluble form of
hydroxypropyl cellulose. The insert is placed in the inferior cul-de-
sac of the eye once or twice daily for the treatment of dry eyes. The
inserts soften and slowly dissolve, thickening the precorneal tear
film and prolonging the tear film breakup.
Pilocarpine Insert
Pilocarpine is available in a membrane- controlled
reservoir system that is used in the treatment of glaucoma.
Pilocarpine is sandwiched between two ethylene vinyl acetate
membranes. It also contains alginic acid, a seaweed
carbohydrate, that serves as a carrier for pilocarpine.

9. Contact lenses
Types of contact lenses:
 Hard contact lenses:
Hard contact lenses provide durability and clear, crisp vision. The lenses
are termed hard because they are made of a rigid plastic resin,
polymethylmethacrylate (PMMA). The lenses are 7 to 10 mm in diameter and
are designed to cover only part of the cornea.
 Soft contact lenses:
Soft contact lenses are made of a hydrophilic transparent plastic,
hydroxyethyl methacrylate, with small amounts of cross-linking agents that
provide a hydrogel network. two general types of soft contact lens: daily wear
and extended wear.

10. Targeting the posterior segment
of the eye
 Systemic drug delivery
Systemic delivery of a drug means it needs to be able to cross the blood–
retinal barrier to reach the retina and vitreous humour.
 Intraocular injections
Intravitreal injections provide the most efficient means of reproducible
drug delivery to the back of the eye.The drug bypasses the blood–
ocular barriers, thus achieving higher intraocular levels, which improve
treatment efficacy

11. Intraocular injections
 Intravitreal injections provide the most efficient
means of reproducible drug delivery to the back of the
eye.The drug bypasses the blood–ocular barriers, thus
achieving higher intraocular levels, which improve
treatment efficacy.

12. Intraocular implants
 Implantable drug delivery systems can be classified into bioerodible
and nonbioerodible systems.
 Nonbiodegradable intraocular implants
Nonbiodegradable systems are commonly ‘reservoir’ devices, whereby the
drug core is coated by a semipermeable polymer through which the
drug can pass, or the polymer coating may have an opening of a fixed
area through which the drug can diffuse out. Further surgery is
required to remove the implant depleted of drug. The risks associated
with this invasive procedure include vitreous haemorrhage, cataract,
retinal detachment and endophthalmitis.

13.  Biodegradable intraocular implants
Biodegradable systems are composed of polymers that are metabolized
by enzymatic or nonenzymatic (e.g. hydrolysis) reactions in vivo into
more soluble forms that can be safely eliminated by the body.
Biodegradable polymers can be made into a variety of shapes and sizes,
including pellets, sheets, discs and rods, through different processes.

14. PHARMACOLOGIC CATEGORIES OF OPHTHALMIC
DRUGS
Topical anesthetics:
cocaine and proparacaine are employed to provide pain relief
also in preoperatively or postoperatively ophthalmic trauma, and during
ophthalmic examination.
 Antifungal agents:
Use topically against fungal endophthalmitis and fungal keratitis are
natamycin, and flucytosine.
 Antibiotic agents:
Systemically and locally to combat ophthalmic infection such as
azithromycin, gentamicin sulfate and sodium sulfacetamide.

15.  Anti-inflammatory agents
Animation of the eye, as allergic conjunctivitis. Among the topical anti-
inflammatory steroidal agents are fluorometholone and dexamethasone salts.
Nonsteroidal anti-inflammatory agents include diclofenac, flurbiprofen, ketorolac,
and suprofen.
 Antiviral agents
As that caused by herpes simplex virus. Among the antiviral agents used
topically are trifluridine, ganciclovir, and vidarabine.
 Beta-adrenergic blocking agents:
As betaxolol hydrochloride and levobunolol hydrochloride are used
topically in the treatment of intraocular pressure and chronic open-angle
glaucoma.

16.  Glaucoma Agents:
Miotics and other glaucoma agents are used in the treatment of
glaucoma, accommodative esotropia, convergent strabismus, and for local
treatment of myasthenia gravis. Among the miotics are pilocarpine and
demecarium bromide.
 Mydriatics and Cycloplegics:
Examination of the fundus by dilating the pupil.
Among the mydriatics and cycloplegics are atropine, scopolamine, and
cyclopentolate.
 Astringents:
Zinc sulfate is a commonly used astringent in ophthalmic solutions.

17.  Protectants and artificial tears:
Employed as artificial tears or as contact lens fluids to lubricate the eye
contain agents such as carboxymethyl cellulose, methylcellulose, hydroxypropyl
methylcellulose, and polyvinyl alcohol.
 Vasoconstrictors and ocular decongestants:
Vasoconstrictors applied topically to the mucous membranes of the eye cause
transient constriction of the conjunctival blood vessels. They are intended to soothe,
refresh, and remove redness due to minor eye irritation. Among the vasoconstrictors
used topically are naphazoline(curine), oxymetazoline, and tetrahydrozoline
hydrochlorides. Antihistamines such as emedastine difumarate, ketotifen fumarate,
and olopatadine hydrochloride are included in some products to provide relief of
itching due to pollen, ragweed, and animal dander.

18. Special Consideration Of Ophthalmic Solutions:
Some important considerations are as follows:
Volume of Eye
The volume capacity of the front of the eye is limited. The average tear volume is about
7 μL, while the maximum volume that can be held in the conjunctival cul-de- sac of the
lower lid is 30 μL.
Bioavailability
Bioavailability of drugs administered via the topical ophthalmic route is affected by a
multitude of factors. Absorption of drugs often occurs primarily through the cornea. The
cornea features a multilayer barrier to absorption. The most anterior layer, the hydrophobic
squamous epithelium, acts as a barrier to hydrophilic molecules while the stroma, the
thickest layer of the cornea, is hydrophilic and acts as a barrier to hydrophobic molecules.
Therefore, molecules that have both hydrophilic and lipophilic properties will typically be
able to penetrate most readily. Binding of the drug by proteins found in the tears can also
reduce bioavailability, as protein-bound drugs are too large to penetrate the corneal
epithelium. The retention time of the medication on the eye is another absorption-limiting
factor. Viscosity and thickening agents may be used in ophthalmic preparations to increase
the time the drug is in contact with the ocular tissue.

19. STERILITY:
 Ophthalmic solutions and suspensions must be Sterilized for safe use.
 It is preferable to sterilize ophthalmics in their final containers by
autoclaving at 121°C (250°F) for 15 minutes,
 We can use bacterial filters instead of it.
 If no preservative is present, then the product is typically dispensed in a
single-use container.
TONICITY:
 Tonicity of ophthalmic products should generally be adjusted to match
physiological conditions.
 Ophthalmic products with an osmotic pressure 0.6–2% sodium chloride
solution causes discomfort to the eye.

20. pH:
 The pH of an ophthalmic formulation may be buffered to
enhance patient comfort And increase stability, solubility,
and bioavailability of the drug.
 The pH Should be similar to that of tears.
 The pH of normal tears is considered to be about 7.4 .
 The pH of an ophthalmic preparation may be buffered for
following reasons.
(a) for greater comfort to The eye,
(b) to render the formulation more stable,
(c) to enhance the aqueous solubility of the drug,
(d) to enhance the drug’s bioavailability

21. Patient Counseling Steps For Administration
It is important to counsel patients on the correct administration of ophthalmic
products both to ensure that therapeutic effect is achieved and to prevent
infection.
 Step 1
Prior to administration, the patient or caregiver’s hands should be washed
thoroughly
 Step 2
To instill the eye drops, the patient’s head should be tilted back. Often it is
recommended to pull the lower eyelid of the eye down to create a pocket to which
the drop is administered. In the case of an ointment or a gel, a thin ribbon can be
applied
 Step 3
Application of gentle pressure applied to the inner corner of the eye near the nose
may also be recommended as this prevents a significant proportion of lacrimal
drainage
 Step 4
The cap must be replaced on the container immediately after administration to
reduce the risk of contamination.

22. Packing
Currently almost all commercially available ophthalmic products
are packaged in plastic containers.
Obvious advantages-ease of use, less spillage, little
breakage- have led to universal acceptance of these plastic
packaging components, consisting of bottles, fitment and closures.
Alcon was the first company to introduce these packaging
components, identified as a “Drop-Tainer” for ophthalmic products.
The plastic bottles for packaging of ophthalmic products
are generally made of Low Density Polyethylene, either with or
without any colorants or with opacifying agents.
High density polyethyleneare also used to meet specific
product requirements.

23. Eye drop:
 Eye drops(Single-dose containers): Plastic bottles(LDPE) are widely
used.
 Eye drops(Multiple- dose containers):Traditionally, glass bottles with
rubber teat dropper were widely used. Now- a-days, plastic
bottles(LDPE) are widely used.
Eye ointments:
 Flexible plastic or collapsible metal tubes are used.
 Caps or closures are generally made from Polypropylene(PP) and
basically seal the container to prevent contamination or leakage of the
product.
Complications with plastic:
 Plastic containers have sorption and permeability characteristics. Volatile
ingredients such as the chlorobutanol and phenylethyl alcohol can
migrate into the plastic and eventually permeate through the walls of the
container. Neutral, Boro-silicate type glass were widely used as a
container for ophthalmic preparations, but glass containers are not widely
used now which has been replaced by plastic containers(more commonly
known as Drop-Tainers).

24.  Ansel's Pharmaceutics dosage form and drug delivery
system.
 Aulton Pharmaceutics 5th edition.
 AAPS Introduction in Pharmaceutical Sciences.
 Pharmaceutical compounding and dispensing.
 Martin's physical pharmacy and pharmaceutical
sciences_ physical chemical and biopharmaceutical
principles in the pharmaceutical sciences.