Ophthalmic Inserts PDF

Ophthalmic inserts • Ophthalmic inserts are defined as sterile solid dosage forms, with a thin, flexible and multi-layered structure, for insertion in the conjunctival sac. (A) Non-Erodible : Example: • Ocusert: (B) Erodible Inserts Examples: • Lacrisert • SODI • Minidisc School of Pharmacy, Unive...

Ophthalmic inserts • Ophthalmic inserts are defined as sterile solid dosage forms, with a thin, flexible and multi-layered structure, for insertion in the conjunctival sac. (A) Non-Erodible : Example: • Ocusert: (B) Erodible Inserts Examples: • Lacrisert • SODI • Minidisc School of Pharmacy, University of Puerto Rico 2 I. Non erodible ocular inserts: • Insoluble insert is a multi-layered structure consisting of a drug containing core surrounded on each side by a layer of copolymer membranes through which the drug diffuses at a constant rate. • e.g. The Ocusert® Pilo-20 and Pilo-40 Ocular system • Designed to be placed in the inferior cul-de-sac between the sclera and the eyelid and to release pilocarpine continuously at a steady rate for 7 days for treatment of glaucoma. School of Pharmacy, University of Puerto Rico 3 Ocusert consists of: • Drug reservoir: Pilocarpine • Carrier material: Alginic acid • Core: Pilocarpine + alginic acid • Rate controlling polymer: Ethylene vinyl acetate copolymer • Release rate: 20 or 40 µg/hr for 7 days • White annular border: impregnated with titanium dioxide (for easy visibility to patient) School of Pharmacy, University of Puerto Rico 4 School of Pharmacy, University of Puerto Rico 5 Placement of Ocusert • To apply the system, wash hands first. Tilt your head back, be steady upward and pull down the lower eyelid to make a pouch. • Place the system into the pouch. Blink a few times and roll your eye to move the insert into place. School of Pharmacy, University of Puerto Rico 6 Advantages of Ocusert: • Therapeutic effectiveness increasing contact time improving bioavailability. • Continuous release rate by and • Round the clock pressure protection • Patient compliance, needs less attention Disadvantages of Ocusert: • Foreign body sensation • Retention difficulties (some patients may be unaware when device is lost from the eye ) • Need for encouragement and instructions for patients • Movement in the eye and transient blurring vision • Side effect of cutting sensation in the eye as when the Ocusert sometimes doubles over in the eye • High cost School of Pharmacy, University of Puerto Rico 7 II. Soluble Ocular inserts: • Soluble inserts consists of all polymeric devices that dissolve or erode at the end of their releases. Types: • Based on natural polymers e.g. collagen. • Based on synthetic or semi synthetic polymers e.g. Cellulose derivatives – Hydroxypropyl cellulose, methylcellulose or Polyvinyl alcohol, ethylene vinyl acetate copolymer. • The system soften in 10-15 sec after introduction into the conjunctival sac, gradually dissolves within 1h , while releasing the drug. • Advantage: Need not to be removed from their site of application. School of Pharmacy, University of Puerto Rico 8 Erodible Inserts 2. SODI: Soluble Ocular Drug Insert. • Small water soluble insert. Sterile, Rod Shaped device. • Composition: Acryl amide, Vinyl Composition: HPC without preservative. Pyrolidone, Ethylacrylate. Weight: 5mg • Weight 15-16 mg. • In 10-15 sec Softens; Use: Dry eye treatment. • In 10-15 min, turns in viscous Liquids; The insert is composed of 5 mg of • After 30-60 min, becomes Polymeric Hydroxypropyl cellulose (HPC) in a rodSolution. shaped form about 1.27 mm diameter by about 3.5 mm long. 1. Lacrisert: • • • • • School of Pharmacy, University of Puerto Rico 9 • Lacrisert (hydroxypropyl cellulose ophthalmic insert) is a sterile, translucent, rod-shaped, water soluble, preservative-free, slow-release, prescription lubricant which is placed in the eye to treat moderate to severe dry eye symptoms and offers once-daily dosing. (Some people may need to use it twice a day for symptom relief). • Lacrisert is usually recommended for patients unable to obtain symptomatic relief with artificial tear solutions. How Lacrisert works? • Lacrisert softens as it dissolves slowly over the course of one day to stabilize and thicken the tear film of the eye. . • As tear film thickens, it can protect the surface of eyes longer, and begins to give relief from dry eye symptoms. • This allows natural tears to be better maintained throughout the day Ø Lacrisert has been proven to relieve the following symptoms of moderate to severe dry eye: Ø dryness, burning, itching, light sensitivity, and blurred vision. 10 School of Pharmacy, University of Puerto Rico School of Pharmacy, University of Puerto Rico 11 School of Pharmacy, University of Puerto Rico 12 Contact lenses • In recent years, the use of contact lenses has increased due to certain advantages they have over eyeglasses. • These are small lenses that are placed directly in the eye, resting on the cornea. • They offer not only aesthetic advantages, in some cases better vision than the eyeglasses. • On the other hand, they are necessary in certain professions as well as in sports practice. • Contact lenses are available in various designs and materials for their manufacture. • This has contributed to the increase in the number of users, and allowing them choosing among a wide variety of lenses. School of Pharmacy, University of Puerto Rico 13 Contact lenses Types of contact lenses: • The three basic types of contact lenses are classified by their chemical composition: • 1. Hard contact lenses. • 2. Soft contact lenses. • 3. Rigid gas permeable (RGP). School of Pharmacy, University of Puerto Rico 15 They are practically impermeable to oxygen and moisture which represents a disadvantage to the breathing and comfort of the cornea. For this reason, these types of lenses are not currently chosen and have b Hard contact lenses: • Made of rigid plastic resin polymethylmethacrylate (PMMA) • They are practically impermeable to oxygen and moisture which affects normal breathing and comfort of the cornea. • For this reason, these types of lenses are not chosen and replaced by gas-permeable lenses. • Today, hard lenses are adapted in cases of lens replacements in people who wear them long ago and still maintain good vision and comfort. • The lenses are 7 to 10 mm in diameter and are designed to cover only part of the cornea. They float on the tear layer overlying the cornea. • Hard lenses require an adaption period sometimes as long as a week for comfort. Even then, because of their rigidity, some patients find them difficult to wear. School of Pharmacy, University of Puerto Rico 16 Hard contact lenses Advantage: • They produce a very good quality of vision and correct the astigmatism (common vision problem due to irregular shape of the cornea) of the cornea (unless it is very high). • They do not tend to accumulate dirt or contaminate, so cleaning is simple. • They are the most durable and those that are most economical. Disadvantages: • Because these lenses do not let oxygen pass through them, the cornea can only obtain oxygen from the tear layer that exists between the lens and the cornea. • These lenses can easily get out of the eye when doing some sudden blinking, so they are not advisable to practice sports. • They require a longer adaptation period than soft lenses, because at the beginning these lenses are very annoying. School of Pharmacy, University of Puerto Rico 17 Soft contact lenses • are made of a hydrophilic transparent plastic, hydroxyethyl methacrylate, with small amounts of cross-linking agents that provide a hydrogel network. • Soft lenses contain 30% to 80% water, which enables enhanced permeability to oxygen. School of Pharmacy, University of Puerto Rico 18 Soft contact lenses Advantages: • Soft contact lenses are more popular than hard lenses because of their greater comfort. • They range from about 13 to 15 mm in diameter and cover the entire cornea. Because of their size and coverage, soft lenses are less likely than hard lenses to dislodge spontaneously. • They also are less likely to permit irritating foreign particles (e.g., dust or pollen) to lodge beneath them. Disadvantages: • However for some patients, soft lenses do not provide the same high level of visual acuity as hard lenses. • They are less durable than hard lenses and carry some risk of absorbing medication concomitantly applied to the eye. School of Pharmacy, University of Puerto Rico 19 Types of soft contact lens based on wearing time • Daily wear : must be removed at bedtime • Extended wear: designed to be worn for more than 24 hours, maximum 7 days without removal for cleaning and disinfection, else the wearer may lead to an eye infection. • Continuous wear is a term that is sometimes used to describe 30 consecutive nights of lens wear. • Disposable wear: do not require cleaning and disinfection for the recommended period of use; they are simply discarded and replaced with a new pair. • Patients should be advised not to wear the lenses for longer than recommended to avoid risk of an eye infection. School of Pharmacy, University of Puerto Rico 20 Rigid gas permeable (RGP/GP) • Lenses permeable to gases (semi-rigid) • Its appearance is similar to hard lenses, but they are porous lenses. • They allow oxygen to pass to the eye, to a greater or lesser extent, depending on the permeability of the material. • Currently, there are materials with a permeability so high that the cornea receives a supply of oxygen similar to what would receive without wearing contact lens • Silicone hydrogel lenses are an advanced type of soft contact lenses that are more porous than regular hydrogel lenses and allow even more oxygen to reach the cornea. School of Pharmacy, University of Puerto Rico 21 RGP contact lenses Advantages • RGP contact lenses take advantage of features of both soft and hard lenses. They are oxygen permeable but hydrophobic. • Thus, they permit greater movement of oxygen through the lens than hard lenses while retaining the characteristic durability and ease of handling. • RGP lenses are more comfortable than hard lenses. • It is the basic type of lenses intended for daily wear; some of the newer superpermeable RGP lenses are suitable for extended wear. School of Pharmacy, University of Puerto Rico 22 Summary of pros and cons of different types of contact lenses • Hard and RGP lenses provide strength, durability, and relatively easy care regimens. • Hard and RGP lenses are easy to insert and remove and are relatively resistant to absorption of medications, lens care products, and environmental contaminants. • Hard and RGP lenses provide visual acuity superior to that provided by soft contact lenses. • Hard contact lenses and RGP lenses require a greater adjustment period for the wearer and are more easily dislodged from the eye. • Soft contact lenses have a shorter adaptation period and may be worn comfortably for longer periods. • Soft lenses do not dislodge as easily or fall out of the eye as readily as the hard lenses. • Soft lenses have a shorter life span than hard or RGP lenses, and the wearer must ensure that the lenses do not dry out. School of Pharmacy, University of Puerto Rico 23 Color additives in contact lenses • Contact lens manufacturers produce both clear and colored lenses. • The use of color additives in contact lenses is regulated by the USFDA. • The FDA permits the use of a specific color additive in contact lenses only after reviewing and approving a manufacturer’s official Color Additive Petition. • The petition must contain the requisite chemical, safety, manufacturing, packaging, and product labeling information for FDA review. School of Pharmacy, University of Puerto Rico 24 Care of contact lenses • With the exception of disposable contact lenses, all soft lenses require a routine care program that includes: • cleaning to loosen and remove lipid and protein deposits, • rinsing to remove the cleaning solution and material loosened by cleaning, and • disinfection to kill microorganisms. • If the lenses are not maintained at proper intervals, they are prone to deposit buildup, discoloration, and microbial contamination. School of Pharmacy, University of Puerto Rico 25 • Hard contact lenses require a routine care program that includes: • cleaning to remove debris and deposits from the lens, • soaking the lens in a storage disinfecting solution while not in use, and • wetting the lenses to decrease their hydrophobic characteristics. School of Pharmacy, University of Puerto Rico 26 Products for care of contact lenses • To achieve the care needs of contact lenses the following types of solutions are used: cleaning solutions, soaking solutions, wetting solutions, mixed-purpose solutions School of Pharmacy, University of Puerto Rico 27 Products for soft contact lenses: Cleaners • The two main categories of cleaners are: surfactants and enzymatic cleaners • Surfactant cleaners emulsify accumulated oils, lipids, and inorganic compounds. • Ingredients in cleaners are: nonionic detergent, wetting agent, chelating agent, buffers, and preservatives. • several drops of the solution is placed on the lens surface and gently rubbing the lens with the thumb and forefinger, or by placing the lens in the palm of the hand and rubbing gently with a fingertip (about a 20- to 30-second). School of Pharmacy, University of Puerto Rico 28 • Enzymatic cleaners, break down and remove protein deposits. • Enzymatic cleaning is done by soaking the lenses in a solution prepared from enzyme tablets. • The enzyme tablets contain papain, pancreatin, or subtilisin, which causes hydrolysis of protein to peptides and amino acids. • Typically, these tablets are added to saline solution/solution can be prepared using 3% hydrogen peroxide, which combines enzymatic cleaning with disinfection. • After the lenses have been soaked for the recommended time, they should be thoroughly rinsed. • This is important to do because a peroxide-soaked lens placed directly into the eye will cause great pain, photophobia, redness, and possible corneal epithelial damage. School of Pharmacy, University of Puerto Rico 29 Rinsing and storage solutions Functions of this solution is: • Rinsing and storage of the lenses, as saline maintains lenses’ curvature, diameter and optical characteristics. • Facilitate lens hydration, preventing the lenses from drying out and becoming brittle. • Some saline solutions contain preservatives, which can induce sensitivity reactions or eye irritation. • To prevent this, preservative-free saline solutions are available in unit-of-use vials. School of Pharmacy, University of Puerto Rico 30 Wetting solutions (used for hard lenses) • Wetting solutions contain surfactants to facilitate hydration of the hydrophobic lens surface and enable the tears to spread evenly across the lens by providing it with temporary hydrophilic qualities. • These solutions also provide a cushion between the lens and the cornea and eyelid. • Typical ingredients include: • viscosity-increasing agent, such as hydroxyethyl cellulose; • wetting agent, such as polyvinyl alcohol; • preservatives, such as benzalkonium chloride or edetate disodium; • buffering agents and salts to adjust the pH and maintain tonicity. School of Pharmacy, University of Puerto Rico 31 Combination Solutions • Combination solutions mix effects such as cleaning and soaking, wetting and soaking, or cleaning, soaking, and wetting. • Easy to use but cleaning effectiveness is low • These combination solutions should be reserved for wearers who have a demonstrated need for simplification of lens care. School of Pharmacy, University of Puerto Rico 32 Maintenance of contact lenses School of Pharmacy, University of Puerto Rico 33 Precautions and recommendations • You should not wear contact lenses while you are sleeping, unless the lens type allows it. • If you sleep with your contact lenses on, your eyes may be damaged because the cornea does not receive enough oxygen. In addition, you run the risk of becoming infected. • In the case of extended use lenses, obey the recommendations of your doctor to know how long you can use them continuously. • Use water soluble cosmetics. • Always remove contact lens before removing makeup. • If you need to use hair spray, you must apply it before putting on the lenses. The lenses should be placed in a different room, because the aerosol particles remain in the air and can stick to the lenses. School of Pharmacy, University of Puerto Rico 34 Precautions and recommendations • Do not use saliva to moisten, clean or to help put it in the eyes. Saliva is not sterile and contains numerous microorganisms, including P. aeruginosa. It can increase the risk of infection in the eyes. • Do not rub your eyes when the lenses are in place, and if irritation develops, the lenses should be removed until these symptoms disappear. • If you feel irritation, redness, pain, high sensitivity to light or blurred vision, you should see your doctor as soon as possible. School of Pharmacy, University of Puerto Rico 35 Precautions and recommendations • It is recommended to use only those products recommended specifically for the type of contact lens you use and whenever possible to use solutions from the same manufacturer. • Cleaning and storage should be done with specific solutions for that purpose. • All contact lens products should be discarded once they expire. • During cleaning, the patient is advised to check if the lens has scratches, cracks and/or breakage, deformation and/or discoloration. • The lenses should be thoroughly cleaned and thoroughly rinsed. If they are not washed and rinsed well they can cause eye discomfort and irritation. School of Pharmacy, University of Puerto Rico 36 Problems with the use of contact lenses • Infections of the eyes • Allergic reactions to the cleaning solutions or to the particles that are deposited on the lenses • Inflammation/redness of the eye • Corneal scrape/scratch • Growth of abnormal blood vessels in the normally transparent area of the cornea. School of Pharmacy, University of Puerto Rico 37 The purpose of the maintenance of contact lenses is: • Keep them in good condition • Disinfect them • Condition them for use. School of Pharmacy, University of Puerto Rico 38 You may find it difficult to use contact lenses if you have: • eyes very irritated by allergies or by exposure to dust or chemicals at work. • a too active thyroid gland, uncontrolled diabetes or tremor or severe arthritis in the hands. • dry eyes because of pregnancy, birth control pills, diuretics, antihistamines, or decongestants. • an eye disease that affects the surface of the eye. School of Pharmacy, University of Puerto Rico 39 Clinical considerations with the use of contact lenses • Although most medicinal drops can be used in conjunction with the use of contact lenses, caution should be exercised and information specific to the drugs used, particularly with soft contact lenses. • Soft lens can absorb certain topical medications and affect the bioavailability of the drug. • The use of ophthalmic suspensions and ophthalmic ointments by contact lens wearers presents some difficulties. • Particles of drugs in ophthalmic suspensions can accumulate between the cornea and the contact lens, causing discomfort and other unwanted effects. • Ophthalmic ointments not only cloud vision but may discolor the lens. • Therefore, an alternative dosage form, such as an ophthalmic solution, may be prescribed, or the use of lenses shall be deferred until the therapy is completed. School of Pharmacy, University of Puerto Rico 40 Clinical considerations with the use of contact lenses • Some medications administered by other routes for systemic effects can reach tears and produce interactions between the contact lens and the drugs. Examples: • orange stain - rifampin • turbidity of the lenses - ribavirin • ocular inflammation - salicylates • refractive changes*-acetazolamide • In addition, drugs that cause ocular side effects have the potential to interfere with the use of contact lenses. • For example, drugs with anticholinergic effects (eg, antihistamines, tricyclic antidepressants) decrease tear secretion and can cause lens intolerance and damage to the eye. shape of your eye does not bend light correctly, resulting in a blurred image. School of Pharmacy, University of Puerto Rico 41 Clinical considerations with the use of contact lenses • Isotretinoin, prescribed for severe acne, can induce marked dryness of the eye and may interfere with the use of contact lenses during therapy. • Medications that promote excessive tearing (eg, reserpine) or eye or eyelid edema (eg, primidone, hydrochlorothiazide, chlorthalidone) may also interfere with lens wear. • The use of ophthalmic vasoconstrictors occasionally causes dilation of the pupil, especially in people who wear contact lenses. • This effect lasts only 1 to 4 hours and is not clinically significant, even so, the FDA has recommended that patients be informed of this side effect on the product label. School of Pharmacy, University of Puerto Rico 42 References • A Practical Guide to Contemporary Pharmacy Practice, 3rd Ed. Philadelphia, Lippincott Williams & Wilkins, 2009 • Gennaro, A.R., Remington Pharmacy (Volumes 1 and 2) 20th ED. Panamericana, 2003 • Allen, L.V., Ansel, H.C. Ansel's Pharmaceutical Dosage Forms and Drug Delivery Systems. 10th Ed. Philadelphia, Lippincott Williams & Wilkins, 2013 School of Pharmacy, University of Puerto Rico 43