Implant infusion pump & ophthalmic inserts.Its advantages, disadvantages, and application.
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Added: Aug 16, 2017
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Submitted by Abhishek Sunil Dhoot ( 160603003) First Year MPharm (Pharmaceutics) IMPLANT INFUSION PUMPS, OSMOTIC PUMP & OPHTHALMIC INSERTS EVALUATORY SEMINAR Under the guidance of Dr. Srinivas Mutalik
INTRODUCTION Implants are small sterile solid masses consisting of a highly purified drug made by compression or moulding. Implants type drug delivery is useful for patients having difficulty in taking drugs orally, and it allows the avoidance of frequent dosage by sustained supply. Implanted infusion pumps are small devices surgically implanted under your skin. They are used when you need long-term medications. 1
IMPLANT INFUSION PUMP IDEAL CHARACTERISTICS It should posses chemical, physical and biological stability Compatible with drug Convenient to use by patients and health professionals Long reservoir. Simple means to performance of the pump Easy to manufacture & relatively inexpensive. Good mechanical strength. 2
OSMOTIC PUMPS ALZET OSMOTIC PUMP 3
Advantages Improved patient convenience and compliance. Reduction in fluctuation in steady-state levels. Increased safety margin of high potency drugs. Maximum utilization of drug . Less frequency of dosing Reduction in health care cost through improved therapy 4
Expensive, as special equipment is required for making the system. If the coating process is not well controlled there is a risk of film defects, which results in dose dumping Tissue or skin damage Disadvantages 5
Basic components of Osmotic Pumps Drug: Both water soluble and water insoluble drugs can be used in the osmotic pump systems. The drug candidate used in the osmotically controlled drug delivery should possess short biological half-life (2-6h), High potency and should be required for a chronic treatment. Nifedipine, Virapamil, Metoprolol, Captopril, Diltiazem hydrochloride, Carvedilol,Valsartan etc...... 6
Osmotic agents: Osmotic agents usually are ionic compounds consisting of either inorganic salts such as sodium chloride, potassium chloride magnesium sulphate, sodium sulphate, potassium sulphate and sodium bicarbonate Hydrophilic polymer s like Sodium carboxymethyl cellulose , Hydroxypropylmethyl cellulose , Hydroxyethylmethylcellulose , Methylcellulose , Polyethylene oxide , polyvinyl pyrollidine. Additionally, sugars such as glucose, sorbitol, sucrose and inorganic salts of carbohydrates can also act as effective osmotic agents. 7
Semi Permeable / Micro porous Membrane Semi permeable membrane plays an important role in the modulation of dug release from the osmotic drug delivery system. It should be stable to both outer and the inner environment of the device. The membrane should be rigid and inert and should maintain its dimensional integrity to provide a constant osmotic driving force during drug delivery. 8
OPHTHALMIC INSERTS Ocular inserts are defined as sterile, thin, solid or semisolid devices placed into conjuctival sac. Its size and shape are especially designed for ophthalmic application. They are composed of a polymeric support that may or may not contain a drug. 9
CLASSIFICATION 10
Diffusion Inserts The diffusion systems are composed of a drug reservoir enclosed in a specially designed semi-permeable or micro porous membrane, which allows the drug to diffuse from the reservoir. The drug release from such a system is controlled by the lachrymal fluid, which permeates through the membrane. The drug delivery rate is controlled by diffusion through the membrane. 11
Ocusert Ocusert is a diffusion-controlled, reservoir-type device marketed in the United States. Pilocarpine ophthalmic (for the eyes) is used to treat glaucoma or ocular hypertension (high pressure inside the eye). Side effects: Flushing Excessive secretion of tears Itching of skin Fatigue Blurred vision 12
Osmotic Inserts The drug and the osmotic solutes are placed in two separate Compartments surrounded by a semi-permeable membrane. The tear fluid diffuses through the semi-permeable membrane, wets them, and induces their dissolution and then released from the deposits of the device. The drug release from the system is generally very rapid at the beginning and then declines exponentially with time. The release of the drug takes place when tears penetrate into the insert. This induces drug release by diffusion and forms a layer of gel around the core of the insert. Contact Lenses 13
Soluble Ophthalmic Inserts Soluble inserts correspond to the oldest class of ocular inserts, which offer the advantage of being wholly soluble, so they need not be removed from the site of application. The soluble ophthalmic inserts are easily processed by conventional methods – E.g. Compression The bioerodible inserts are composed of homogeneous dispersion of a drug which can be included in or not included in the hydrophobic coat made of bioerodible polymers. Drug release from such a system is due to the contact of the device with the tear fluid, inducing a superficial bioerosion of the matrix. Bioerodible Ophthalmic Inserts 14
Advantages and disadvantages: prolonged drug activity and higher bioavailability Release of drugs at a slow, constant rate Accurate dosing Sterility. Stability. Increased shelf life with respect to aqueous solutions. A major disadvantage of ocular inserts resides in their ‘solidity’, that is, they are felt by the (often oversensitive) patients as an extraneous body in the eye. Difficulty in placement of the ocular inserts 15
Lacrisert Lacrisert is a sterile ophthalmic insert used in treatment of Dry eye syndrome and is usually recommended for patient unable to obtain symptomatic relief with artificial tear solutions 16
CONCLUSION Implantable infusion pumps are especially well suited for long term delivery of drugs. They are free from toxicity and are safe and effective. Ocular inserts Reduced frequency of administrations and thus better patient compliance with lower incidence of visual side effects. 17