Ocusert

Ophthalmic dmg dehveiy systems (qv) have been developed to dehvei controlled dmg quantities for a prolonged time (up to seven days) to the eye, eg, pilocarpine [92-13-7J (17). Alza Corp. in conjunction with Ciba-Geigy Corp. originally marketed such a product known as Ocusert to treat glaucoma. 

Fig. 2. Ocusert ocular therapeutic system. The Ocusert system releases pilocarpine at a controUed rate to treat glaucoma. In this schematic representation, the three disks and the ring are shown two-dimension ally. The patient inserts the Ocusert system under the eyeUd, where it releases pilocarpine for seven...

Fig. 1. Ocusert Pilo-20 and Ocusert Pilo-40 therapeutic systems, (a) Dimensions of the P20 system P40 systems are 5.5 mm and 13.0 mm, respectively (b)...

Fig. 2. In vivo release rate of pilocarpiae from the Ocusert Pilo-40 ocular therapeutic system where (—) represeats the calculated rate, and (—...

Fig. 3. Release rate of pilocarpine from Ocusert Pilo-20. Data points shown with standard deviation error bars (94).

Minims Pilocarpine (Chauvin as nitrate) Ocusert Pilo (Dominion) Pilogel (Alcon)... 

Ethylene vinyl acetate has also found major applications in drug delivery. These copolymers used in drug release normally contain 30-50 wt% of vinyl acetate. They have been commercialized by the Alza Corporation for the delivery of pilocarpine over a one-week period (Ocusert) and the delivery of progesterone for over one year in the form of an intrauterine device (Progestasert). Ethylene vinyl acetate has also been evaluated for the release of macromolecules such as proteins. The release of proteins form these polymers is by a porous diffusion and the pore structure can be used to control the rate of release (3). Similar nonbiodegradable polymers such as the polyurethanes, polyethylenes, polytetrafluoroethylene and poly(methyl methacrylate) have also been used to deliver a variety of different pharmaceutical agents usually as implants or removal devices. 

The Ocusert Pilo-20 and Pilo-40 Ocular Therapeutic System is an elliptical membrane that is soft and flexible and 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. The design of the dosage form is described by Alza in terms of an open-looped therapeutic system, having three major components (a) the drug, (b) a... 

Fig. 14 Schematic diagram of the Ocusert intraocular device for release of pilocarpine.

Initiation of therapy - It has been estimated that 20 meg Ocusert is roughly equal to 0.5% or 1 % drops and 40 meg is roughly equal to 2% or 3% drops. Therapy may be started with the 20 meg system, regardless of the strength of pilocarpine solution the patient previously required. Because of the patient s age, family history, and disease status or progression, however, therapy may be started with the 40 meg system. 

Pilocarpine ocular therapeutic system (Ocusert) Carefully consider and evaluate patients with acute infectious conjunctivitis or keratitis prior to use. 

I Brand Name(s) Adsorbocarpine, Akarpine, Isopto Carpine, Ocu-Carpine, Ocusert, Pi-lagan with C Cap, Pilocar, Pilopine-HS, Piloptic-HS, Piloptic-1, Piloptic-1/2, Pilop-tic-2, Piloptic-3, Piloptic-4, Piloptic-6, Pilostat, Salagen... 

Ophthalmic sustained-release inserts (Ocusert Pilo-20, Ocusert Pilo-40) release 20 and 40 meg pilocarpine per hour for 1 week, respectively... 

Nondegradable polymers are also useful as matrices for ocular implants. This application requires the polymer to be hydrophilic, to minimize local tissue irritation. Need for ocular implants stems from the challenges posed to conventional ocular medicines (i.e., eye drops) such as rapid dilution, tear washout, poor patient compliance, and limited bioavailability. Ocular implants from hydrophilic polymer matrices that provide localized sustained release may overcome the above limitations. The first polymeric sustained release product to reach the market was Ocusert , a pilocarpin sustained release ocular implant developed by Alza. Ocusert has the drug reservoir as a thin disc of pilocarpine-alginate complex sandwiched between two transparent discs of microporous membrane fabricated from ethylene-vinyl acetate copolymer. The microporous membranes permit the tear fluid to penetrate into the drug reservoir compartment to dissolve pilocarpine from the complex. Pilocarpine molecules are then released at a constant rate of 20 or 40 pg/hr for a four- to seven-day management of glaucoma. 

Pilocarpine is the active ingredient in Ocusert , an antiglaucoma agent, which can be inserted behind the lower eyelid. 

Ocusert - [CONTROLLED RELEASE TECHNOLOGY - PHARMACEUTICAL] (Vol 7) - [PHARMACEUTICALS] (Vol 18) -use m drug delivery [DRUG DELIVERY SYSTEMS] (Vol 8)... 

Figure 12.7 The Ocusert pilocarpine system is a thin multilayer membrane device. The central sandwich consists of a core containing the drug pilocarpine. The device is placed in the eye, where it releases the drug at a continuous rate for 7 days. Devices with release rates of 20 or 40 p,g/h are used. Controlled release of the drug eliminates the over- and under-dosing observed with conventional eyedrop formulations, which must be delivered every 4-6 h to maintain therapeutic levels of the drug in the eye tissue [18]...

The Ocusert system illustrated in Figure 12.7 is one example of a diffusion-controlled reservoir device. Another is the steroid-releasing intrauterine device (IUD) shown in Figure 12.9. Inert IUDs of various shapes were widely used for... 

The Ocusert (pilocarpine) Pilo-20/Pilo-40 Ocular Therapeutic System, Alza Corporation, Palo Alto, CA (1974). 

Diffusion-controlled membranes exist in two categories depot systems, in which the drug is totally encapsulated within a reservoir, and monolithic systems, where the drug is dispersed in a rate-controlling polymer matrix [25]. One commercially successful depot device is the Alza Ocusert for ocular delivery of pilocarpine in the treatment of glaucoma [25]. 

Ocular Ocusert implant Vitrasert intravitreal implant... 

EVA copolymers are also used in fabricating Progestasert and Ocusert which are an intrauterine and an ocular drug delivery device for pilocarpine and progesterone, respectively. These are discussed in Chapters... 

An alternative system, manufactured as a wafer-like insoluble implant, has been developed (Ocusert). The system is preprogrammed to release pilocarpine at a constant rate of 20 or 40 / g/hr for a week to treat chronic glaucoma however, release from inserts may be incomplete and approximately 20% of all patients treated with the Ocusert lose the device without being aware of the loss. The device also presents problems including foreign-body sensation, expulsion from the eye, and difficulty in handling and insertion. An alternative to the advanced non-erodible systems is an erodible insert for placement in the cul-de-sac. 

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