Objectives of the project: (a) Develop a formulation of Atenolol HCL microemulsion for ocular application to decrease IOP in case of glaucoma. (b) Improve the quality of patient’s life suffering from glaucoma. (c) Reduce the number of dosing per day. 1.1 Eye
"If a physician performed a major operation on a seignior (a nobleman) with a bronze lancet and has saved the seignior's life, or he opened the eye socket of a seignior with a bronze lancet and has saved the seignior's eye, he shall receive ten shekels of silver. But, if the physician in so doing has caused the seignior's death or has he destroyed the seignior's eye, they shall cut off his hand" the forgoing excerpts are from 282 laws of King Hammurabi's Code.
The eye is unique in its therapeutic challenges. An efficient system, that of tears and tear drainage, which quickly eliminates drug solutions which makes topical delivery to the eye somewhat different from most other areas of the body.
Preparations for the eye comprise a variety of different types of products; they may be solutions (eye drops or eyewashes), suspensions, or ointments.
Any modern text on drug product design and evaluation must place into perspective the unique nature of the ophthalmic dosage form in general more specifically. It must consider that the bodily organ which, probably better than any other, serves as a model structure for the evaluation of drug activity, the eye. In no other organ can the practitioner, without surgical or mechanical interaction, so well observe the activity of the drug being administered. Most ocular structures can be readily viewed from cornea to retina and in doing so; any signs of ocular or systemic disease can be detected long before sight-threatening or certain health threatening disease states become intractable.
Behind the relative straightforward composition nature of ophthalmic solutions and ointments, however, like many physicochemical parameters which affect drug stability, safety and efficacy as they do most other products. Additionally, specialized dosage forms such as parenteral type ophthalmic solutions for intraocular, subtenons, and retrobulbar use; suspensions for insoluble substances such as hydrocortisone; and solids for reconstitution such as ecothiophate iodide and tetracycline, all present the drug product designer with composition and manufacturing procedure challenges in the development of pharmaceuticals.
Opthalmic products, like most others in the medical armamentarium, are undergoing a process termed optimization. New modes of delivering a drug to the eye are being actively explored ranging from a solid hydrophobic device which is inserted into the ophthalmic cul-de-sac, to conventionally applied dosage forms which, due to their formulation characteristics markedly increase the drug residence time in the orbit of the eye, thus providing drug for absorption for prolonged period of time and reducing the frequency with which a given drug product must be administered .
Ocular diseases are mainly treated topically by application of drug solutions administered as eye drops. These conventional dosage forms account for 90% of the available ophthalmic formulations. This can be due to the simplicity and convenience of such dosage forms .
It is often assumed that drugs administered topically to the eye are rapidly and totally absorbed and are available to the desirable site in the globe of the eye to exert their therapeutic effect. Indeed, this is generally not the case. When a quantity of topical ophthalmic dosage form is applied to the eye, generally to the lower cul-de-sac, several factors immediately begin to affect the availability of the drug contained in that quantity of the dosage form. Upon application of 1 to 2 drops of a sterile ophthalmic solution, there are many factors, which will participate in the removal of the applied drops from the lower cul-de-sac .
The first factor effecting...