Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Carbohydrate doai
Reexamination Certificate
2001-06-29
2003-09-30
Fay, Zohreh (Department: 1614)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Carbohydrate doai
C514S912000, C424S078040
Reexamination Certificate
active
06627620
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a composition set and a kit for use in intraocular surgery, preferably in cataract operations.
The present invention has appeared in connection with intraocular operations, especially operations for cataract.
In the following the problems will primarily be described in connection with such surgical interventions, however it will be within the scope of the invention to indicate composition set and kit which may be used in connection with other kinds of intraocular operations.
In connection with operating the eye for cataract, a marked change with the technique used by local anesthesia has occurred within the recent years. This has taken place with the intention of introducing less risky techniques.
In recent years, traditional injection behind the eyeball has been substituted by drops with local anaesthetic effect on the surface of the eye. Pain and discomfort may arise in connection with an operation anaesthesia with drops. This is probably caused by movements and pulling, especially of iris. Patients only having been anaesthetised in the surface of the eye have described greater or lesser feeling of discomfort and pain during the operation. These drawbacks have, however, not diminished the popularity of anaesthesia with drops. The patients have thus found it advantageous to avoid the injection behind the eyeball and also for the surgeons drop anaesthesia is a rational advantage.
It has appeared that the discomfort experienced by the patient, only to a small degree is influenced by sedatives given pre- or peri-operatively. On the contrary, it has appeared that the discomfort may be reduced by intraocular use of local anaesthesia.
Therefore, in the later years is has been practice to combine the anaesthesia with drops with intraocular local anaesthesia, preferably lidocaine hydrochloride in a concentration of 1%, which is injected into the anterior eye chamber at the beginning of the operation and later, possibly before implantation of an artificial lens in the eye.
Seeing that the present invention especially will be used in connection with operations for cataract, a more detailed description of such a surgical technique will be given.
The larger part of all surgical interventions takes place in local anaesthesia where, before the operation, sedatives are given and dilatation of the pupil is established. In situations where injection or infiltration anaesthesia is used, injections are given between 10 and 20 minutes before an operation. This is usually given by the surgeon or anaesthetist. By anaesthesia with drops, only drops with local anaesthetic effect are given from about 15 minutes before the start of the operation. This is given by operating theatre assistants. Normally the application of drops is repeated 3-6 times before the operation and it may possibly be supplemented during the operation.
By anaesthesia with drops, the drops are given by nurses, and the surgeon may initiate the operation immediately when preparation in the form of washing and exposing has been performed by a nurse.
The surgeon initiates the intervention by making a small incision in the eye at the rim of the cornea. Herethrough intraocular anaesthesia is given by injection of about 0.2 ml in the anterior eye chamber at first. Thereafter the viscoelastic agent is injected as an amount of about 0.2 ml in the anterior eye chamber. This is to prevent collapsing of the eye as well as giving protection to the back of the cornea during the operation.
Hereafter an opening is established at a second position along the rim of the cornea, the opening serving as access for the operation itself. Through this second opening a hole is made in the lens capsule (capsulorhexis), after which the lens is released in the capsule by means of liquid. Then the core and the cortex of the lens are removed with so-called Phaco emulsification and suction. This implies that the lens is split up into smaller pieces that may be sucked out. The remaining capsule now appears as a sack suspended with thin threads (zonula threads). This sack is used as fixation of the new artificial lens in the posterior chamber of the eye right behind the pupil.
Immediately before implantation of the artificial lens, the sack is filled with viscoelastic agent. At the same time, the intraocular anaesthetic may possibly be supplemented before implantation of the lens. After implantation of the lens, the viscoelastic agent is sucked out of the eye. The tightness of the wound is ensured, possibly by means of a suture, and hereafter the operation is finished.
In cases where anaesthesia with drops is used, possibly combined with intraocular anaesthesia, the patient is able to see immediately after the operation has been finished and it is not necessary to make a dressing. This is an advantage as compared to the earlier known injection anaesthesia where is was necessary to provide the patient with a dressing and where the patient had to wait one day before he was able to see.
By the more recent techniques used for operation of cataract today, viscoelastic agents are used by routine, the agents comprising methyl hydroxypropyl cellulose, sodium hyaluronate, or sodium chondroitin sulphate, or mixtures thereof. The viscoelastic agents may be of different molecular weight and concentration and thereby different viscosity.
By the cataract surgery introduced in the later years, viscoelastics have achieved wide speed application. It has been possible to acquire such a viscoelastic as a commercial product for use in eye surgery. Thus it is possible to acquire the agent provided in syringes ready for use at the operation. Viscoelastics were initially prescription drugs but today they have status as over-the-counter drugs for use in intraocular surgery.
The local anaesthesia necessary for cataract operations is sufficient as anaesthesia with drops only. By the newer forms of cataract surgery (Phaco emulsification of the core of the lens through small incisions) it has only been necessary to achieve pain relief at the surface of the eye (analgesia), where it has not been necessary to establish a condition where the eye is standing still (akinesia) or a situation where the eye cannot see (amaurosis). In order to establish analgesia, an anaesthesia with drops has been applied, with dripping from 3 to 6 times as from 15 minutes before the operation until possibly during the operation. This has appeared to be sufficient in order to perform the surgical intervention in a secure and rational way. As previously mentioned, some patients have experienced discomfort when only anaesthesia with drops has been used, probably provoked by structures within the eye. This discomfort has caused increased use of pre- as well as peri-operative sedation by cataract surgery in anaesthesia with drops with the consequent risks of potential complications provoked by this sedation. Also, the discomfort of the patient during anaesthesia with drops has given rise to tensions and uneasiness with disadvantageous consequences for the surgeon's working conditions.
The intraocular anaesthesia used for relieving this discomfort is a specially made product not made or known commercially. It will thus be necessary to suck up anaesthesics into syringes which are transferred to the sterile preparation. There is a possibility of variation in the quality (purity and concentration) of the product made and an irrationality at the individual making of this anaesthesic. Furthermore, by the handling there is a not insignificant risk of contamination and maybe exchange by mistake as other syringes are also used at the operation.
The quality of the product made is critical. Thus the concentration is especially critical as experience shows that higher concentrations probably are toxic to the cornea. Furthermore, anaesthesia of the retina has been described.
In practice only small amounts between 0.2 and 0.5 ml are used, which are injected in one or more doses during the operation. Usually there is used between 0.2 and 0.3 ml at the start of the ope
Dykema Gossett PLLC
Fay Zohreh
LandOfFree
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