RU2114000C1 - Intraocular lens and method of its manufacture - Google Patents

Abstract

FIELD: manufacture of intraocular lens used for vision correction after removal of cataract. SUBSTANCE: lens allows protection of eye from harmful effect of close ultraviolet and violet light with wave length of 350-450 nm due to introduction into lens silicon material of addition from dihydroxide of silicon pyroporphyrin and dihydroxide of silicon tetrabenzoporphyrin in ratio of 10: 1. Addition is introduced in the amount of not more than 0.01 mas. % of material total weight in the course of mixing of components. EFFECT: higher efficiency. 2 cl, 2 dwg

Description

 The invention relates to the manufacturing technology of intraocular lenses (IOLs), which are used in medicine and ophthalmic technology to correct vision after cataract removal.

 Known intraocular lens of polymeric materials (US patent N 4206518, CL A 62 F 2/16, 1980), containing the optical and supporting parts.

 Also known is an intraocular lens containing optical and support parts made of silicone material (ed. St. USSR N 1428368, class A 61 F 2/16, 1988).

 Silicones, as a material for IOLs, have such valuable qualities as high transparency, biological inertness, softness and elasticity, weightlessness in the moisture of the eye, and manufacturability in the manufacturing process of IOLs. However, a serious drawback of silicone IOLs is that they do not protect the eye from the harmful effects of near-ultraviolet (UV) and violet light (λ = 350 - 450 nm).

 A known method for producing intraocular lenses (European patent application N 0335312, class A 61 F 2/16, 1989), comprising mixing the components of the silicone composition, removing air from the resulting mixture under vacuum, pouring the resulting composition into a mold, heating to a vulcanization temperature, followed by cooling and additional heating.

 This method does not allow to obtain an IOL from silicone material that protects the eye from the harmful effects of near UV and violet.

 The task of developing an IOL made of silicone material that protects the eye from the harmful effects of near UV and violet light, as well as the method for their manufacture, remained unresolved.

 The problem is solved in that an IOL containing silicon porphyrins in an amount of up to 0.01% of the total mass of the material, including silicon dihydroxide pyroporphorphyrin and silicon tetrabenzoporphyrin dihydroxide, is introduced into the silicone material in the IOL containing the optical and support parts of silicone material.

That is, it is proposed that as substances blocking the near UV and violet regions of the spectrum, silicon porphyrins were used in silicones, which have an absorption band in the spectrum in the region of 400-430 nm of very high intensity, the molar absorption coefficient ε = (2 ^o C 4) • 10 ⁵ . These compounds have high chemical and thermal stability, are practically insoluble in water. They are not toxic, the porphyrin skeleton forms the basis of such vital natural compounds as chlorophyll, hemoglobin.

The problem is solved in that the composition for the manufacture of IOL of the present invention contains, by weight. hours:
Vinyl-terminated polydimethylmethylphenyl or polydimethyl-diphenylsiloxane (PIC) - 100
Oligovinylsiloxane (OVS) - 5 - 15
Oligohydridesiloxane (OHS) - 10 - 20
Platinum catalyst - 0.2 - 1.0
Premature vulcanization inhibitor - 0.2 - 0.4
Silicon pyroporphyrin dihydroxide - 0.005 - 0.010
Silicon tetrabenzoporphyrin dihydroxide - 0.0005 - 0.0010
The PIC contains in its composition 35 - 55 mol.% Dimethylsiloxy units and 65 - 45 mol.% Methylphenylsiloxy units or 67.5 - 77.5 mol.% Dimethylsiloxy units and 32.5 - 22.5 mol.% Diphenylsiloxy units.

The end groups are dimethylvinylsiloxy, methyldivinylsiloxy or trivinylsiloxy. Refractive index n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.49 - 1.51; viscosity 10000 - 50,000 cSt.

Oligovinylsiloxane contains 10-15 mol% of methylvinylsiloxy units; refractive index n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.49 - 1.51; viscosity - 500 - 2000 cSt.

Oligohydridesiloxane contains 30-50 mol% of methylhydridesiloxy units; refractive index n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.49 - 1.51; viscosity - 100 - 1000 cSt.

 The platinum catalyst is a 1% solution of the complex of Pt with tetravinyl dimethylsiloxane in oligovinylsiloxane.

 The premature vulcanization inhibitor is maleic acid diethyl ether.

Reddish-colored silicon pyro-porphyrin dihydroxide was prepared from pyro-porphyrin XY and silicon tetrachloride according to the known method: M. Gouterman, FP Schwarz, PD Smith, D. Dolphin, J. Chem. Physics, 59, N 2, 676-690 (1973), were purified by chromatography using a column of Al ₂ O ₃ . The electronic spectrum contains absorption bands with λ 576 nm (I), 543 nm (II), 410 nm (III).

Silicon tetrabenzoporphyrin dihydroxide (green) was obtained from tetrabenzoporphyrin and silicon tetrachloride in the same manner as pyroporphyrin dihydroxide was purified by chromatography using an Al ₂ O ₃ column. The electronic spectrum in the visible region contains absorption bands with λ 636 nm (1), 587 nm (III), 432 nm (III), 403 nm (IV); absorption coefficient ε of the band Ш ≫ ε (I)> ε (IV) ≃ ε (II).
The use of oligovinylsilane in a concentration of less than 5 wt. including leads to a decrease in the strength and elastic modulus of the IOL, an increase in the adhesion of the IOL to the optical form. The use of oligovinylsiloxane in an amount greater than 15 wt. h., leads to an excessive increase in the elastic modulus of the lens and a decrease in its strength.

 The use of oligohydridesiloxane in an amount of less than 10 wt. hours, leads to a decrease in the strength of the IOL; at a concentration of oligohydridesiloxane greater than 20 wt. h, the biological inertness of the lens is reduced due to an increase in the concentration of unreacted Si-H groups.

 When using a platinum catalyst in an amount of less than 0.2 wt. h., the rate of vulcanization of the IOL material is reduced in the manufacture of IOL; increase in concentration above 1.0 parts by weight impractical for economic reasons.

 When the concentration of the inhibitor is less than 0.2 parts by weight, unwanted vulcanization of the composition occurs to a significant extent when stored at room temperature; at a concentration above 0.4 wt. including decreases the rate of vulcanization of the composition in the manufacturing process of IOL.

 The use of silicon pyroporphyrin dihydroxide in an amount less than 0.0005 parts by weight does not provide for blocking by the lens of light with a wavelength of λ = 400 - 430 nm; with an increase in concentration above 0.010 parts by weight IOL absorption increases too much in the region of 500 - 700 nm.

Silicon tetrabenzoporphyrin dihydroxide is introduced into the composition to optically compensate for the red color of silicon pyroporphyrin dihydroxide and the concentration of these additives is tightly interconnected [the concentration of Si (TBP) (OH) ₂ is 10 times lower than the concentration of Si (PP) (OH) ₂ ]. Therefore, when using silicon tetrabenzoporphyrin dihydroxide in an amount less than 0.0005 parts by weight, the lens does not completely block light with a wavelength of λ = 400 - 430 nm; when using Si (TPB (OH) ₂ in an amount greater than 0.001 parts by weight, the absorption of the lens increases too much in the region of 500 - 700 nm.

 The invention is illustrated in the drawing, where in FIG. 1 shows an intraocular lens; in FIG. 2 is a graph of the electronic transmission spectrum of the IOL.

 The intraocular lens consists of the optical part 1 and the supporting part 2 and is made of silicone material, into which an addition of silicon porphyrins is introduced, which gives the IOL a light yellow color, thereby eliminating the negative effect of near-UV and violet light on the eye (λ = 350 - 450 nm).

 The electronic transmission spectrum of the IOL with the addition of pyroporphyrin or silicon tetrabenzoporphyrin according to example 3 is shown in the graph of curve 4, and without additives, curve 3.

Example 1. 100 parts by weight polymethylphenylsiloxane with terminal methyldivinylsiloxy groups (n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.4910, ν = 19500 cSt), 9 parts by weight oligovinylsiloxane (n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.4920, ν = 900 cSt), 13 parts by weight silo oligohydride (n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.4910, ν = 550 cSt), 0.4 parts by weight platinum catalyst, 0.2 wt.h. inhibitor, 0.005 wt. including dihydroxide pyroporphyrin silicon, 0.0005 parts by weight silicon tetrabenzoporphyrin dihydroxide is thoroughly mixed, the mold for the manufacture of IOLs is poured, heated at 265 ± 5 ^o C for 10 min, cooled to room temperature. The finished silicone lens is removed, additionally heated at 250 ± 10 ^° C for 10 minutes. The crystalline lens thus obtained is painted in a slightly yellow color, the transmission coefficients in the field of biologically active radiation with a wavelength of λ = 400 - 430 nm for silicone lenses with a diopter of 15 to 25 diopters are used from 9.0 to 2.5%; in the range of 500 - 700 nm for lenses of 15 - 25 diopters, the transmittance is 84 - 77%.

Example 2. From a composition comprising 100 parts by weight trivinylsiloxy terminated polydimethylphenylsiloxane (n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.5010, ν = 22000 cSt), 10 parts by weight oligovinylsiloxane (n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.4940, ν = 900 cSt), 15 parts by weight silo oligohydrides (n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.4910, ν = 550 cSt), 0.6 parts by weight platinum catalyst, 0.3 wt.h. inhibitor, 0.0075 parts by weight silicon pyroporphyrin dihydroxide, 0.00075 parts by weight silicon tetrabenzoporphyrin dihydroxide, an IOL is prepared according to the description of Example 1. An IOL is obtained that is painted in a slightly yellow color, with a transmittance in the region of 400 - 430 nm for lenses with a diopter of 15 - 25 diopters from 2.8 to 0.4%; in the region of 500 - 700 nm - 67 - 78%.

Example 3. Silicone composition of 100 parts by weight trivinylsiloxy terminated polydimethylmethylphenylsiloxane (n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.5050, ν = 31000 cSt), 12 parts by weight oligovinylsiloxane (n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.5000, ν = 900 cSt), 16 parts by weight silo oligohydrides (n $\genfrac{}{}{0ex}{}{\text{20}}{\text{D}}$ 1.5020, ν = 250 cSt), 1.0 wt.h. platinum catalyst, 0.4 wt. including inhibitor, 0.010 parts by weight silicon pyroporphyrin dihydroxide, 0.001 parts by weight silicon tetrabenzoporphyrin dihydroxide is used for the manufacture of IOLs as described in Example 1. A yellowish IOL is obtained with a transmittance in the region of 400 - 430 nm for lenses with a diopter of 15 - 25 diopters equal to 0.1 - 0.8%, in the region of 500 - 700 nm - from 59 to 71%.

 The IOLs obtained in Examples 1-3 were extracted with benzene in a Soxhlet apparatus for 4 h. In this case, the electronic transmission spectrum of the IOL did not change, and the extract did not stain, which indicates that silicon porphyrin additives are chemically bound to the IOL material.

Claims (2)

 1. An intraocular lens containing optical and support parts made of silicone material, characterized in that an addition of silicon porphyrins is added to the silicone material in an amount of not more than 0.01% of the total mass of the material, including silicon pyroporphyrin dihydroxide and silicon tetrabenzoporphyrin dihydroxide.  2. A method of manufacturing an intraocular lens from a silicone composition by mixing components, pouring into a mold, heating to a vulcanization temperature, followed by cooling and additional heating, characterized in that during the mixing of the composition, an additive is added to it, including silicon pyro porphyrin dihydroxide and silicon tetrabenzoporphyrin dihydroxide in a ratio of 10: 1, respectively, in an amount of not more than 0.01% of the total weight of the material.

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