Drug – bio-affecting and body treating compositions – Radionuclide or intended radionuclide containing; adjuvant... – Molecular bilayer structure
Patent
1986-04-30
1988-08-16
Swisher, Nancy A. B.
Drug, bio-affecting and body treating compositions
Radionuclide or intended radionuclide containing; adjuvant...
Molecular bilayer structure
424 2, A61K 908, A61K 4700, A61K 4900
Patent
active
047643609
DESCRIPTION:
BRIEF SUMMARY
This invention is concerned with a colored composition to be used in ophthalmology and consisting of an aqueous solution of a high molecular polymer to which a polymeric dyestuff has been added.
Viscoelastic solutions of highly purified hyaluronic acid (Healon.RTM., Pharmacia AB, Uppsala, Sweden) are nowadays commonly employed in eye surgery practice. Examples of such surgical operations are corneal transplantations, cataract surgery and glaucoma surgery, the Healon.RTM. being injected into the anterior eye chamber in order to maintain that chamber in its correct shape during the operation. For vitrectomy and in cases of retinal detachment the substance is similarly injected into the vitreous chamber (i.e. the space normally occupied by the vitreous humor) so that then the injected substance, in cooperation with residual vitreous humor, will retain the retina in a properly fixed position.
Healon.RTM. is a solution that is entirely clear and colorless. These properties while being excellent-in themselves nevertheless do have the drawback that the substance is not readily observable during the operation and cannot be clearly distinguished from e.g. natural vitreous humor and aqueous humor inasmuch as both of these have approximately the same optical properties as Healon.RTM.. Therefore, in order to facilitate inspection during the operation, Zirm (Klin. Mbl. Augenheilk. 181 (1982), 426-428) has reported a series of tests employing fluorescein additions to Healon.RTM..
Furthermore also methyl cellulose has been tested in eye surgery despite the fact that it has different properties in some respects. Methyl cellulose, too, is a colorless substance, and for this reason Fechner et al. have carried out experiments (British Journal Ophthalmology 67 (1983) 259-263) in which solutions of the polymeric substance are stained with patent blue (patent blue V; Martindale: The Extra Pharmacopoeia 27th ed. London, Pharmaceutical Press, 1977:475) when employed in eye lens implantation surgery.
However, the eye surgeon's work has not really been facilitated to any major extent by the aforesaid attempts at improving the discernibility of the solution of polymeric substance in the eye, where in addition to said polymeric substance--that is, hyaluronic acid or methyl cellulose--there are other components present which have similar optical properties. The reason for the substantial failure of such attempts is that dyes of the aforesaid type are capable of diffusing out of the polymer rather quickly, thereby bestowing their color on surrounding tissue. This in turn means that it will be very difficult to discern details during the course of an operation where such a prior art product has been applied. Moreover in case fluorescein is used this involves the necessity of irradiating the area with a UV lamp in order to render the dye and thus the polymer solution visible to inspection. This irradiation however is a somewhat undesirable expedient since it may have a negative effect on sensitive tissue in the patient's eye.
Thus there is a true need for staining methods by which solutions of polymeric substances of the hyaluronic acid or methyl cellulose type can be stained in a manner such that (i) the dye is maintained clear in the solution and (ii) if by any chance some of the dye leaks out it will not stain the surrounding tissue.
We have now found that a composition having the desired properties is obtained if the added dye is a sufficiently high molecular weight polymeric substance which is soluble in the composition. Consequently this invention relates to a colored composition consisting of a solution of a high molecular polymer to which has been added a dye having a molecular weight of at least 10,000.
Examples of the high molecular polymer are given in prior art literature, with Healon.RTM. being the foremost representative; but methyl cellulose, too, is an example of a useful polymer.
The polymeric dye should be hydrophilic and have a molecular weight exceeding 10,000, preferably exceeding 30,000. Advantageously the molecular
Pharmacia AB
Philpitt Fred
Swisher Nancy A. B.
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