Action And Clinical Pharmacology: Sodium hyaluronate is a physiological material found in both animal and human tissues. It is a polysaccharide consisting of a repeating disaccharide of N-acetylglucosamine and sodium glucuronate, linked by alternating b-1,3 and b-1,4 glycosidic bonds. Chemically identical in all species, hyaluronate can be found in the vitreous and aqueous humor of the eye, in synovial fluid, in skin and in the umbilical cord. Biolon is a sterile 1% solution of highly purified, high molecular weight viscoelastic sodium hyaluronate in phosphate- buffered saline.
When introduced into the anterior segment of the eye during surgical procedures, Biolon maintains a deep anterior chamber throughout surgery, facilitates surgery and reduces trauma to the corneal endothelium and surrounding tissues.
Its viscoelasticity also helps to repel the vitreous face and discourage formation of a postoperative flat chamber. Biolon creates a clear field of vision during and after surgery. It does not interfere with epithelization and normal wound healing. Any traces of Biolon left in the anterior segment of the eye after surgery dissipate through Schlemm’s canal within a week.
Indications And Clinical Uses: Eye surgery, including intraocular lens insertion, intracapsular and extracapsular lens extraction, glaucoma surgery, corneal graft surgery for accidental trauma.
Contra-Indications: When used as recommended, there are no known contraindications.
Precautions: Precautions are limited to those normally associated with the surgical procedures being performed.
Instilling excessive amounts of Biolon into the anterior segments of the eye may increase intraocular pressure. Increased postoperative intraocular pressure may also be caused by a pre-existing glaucoma condition or by compromised outflow and by operative procedures and sequelae thereto, including enzymatic zonulysis, absence of an iridectomy, trauma to filtration structures, and by blood and lenticular remnants in the anterior chamber.
Because these factors vary from case to case and are difficult to predict, the following precaution is recommended: Do not overfill the eye with Biolon.
At the end of surgery, all remaining Biolon should be removed by irrigation or aspiration.
Carefully monitor the intraocular pressure, especially during the immediate postoperative period. If a significant increase in pressure is observed, treat appropriately.
Avoid the trapping of air bubbles behind Biolon. Biolon is a very highly purified substance extracted from bacterial cells. Since the presence of minute quantities of impurities (proteins, etc.) cannot be totally excluded, the physician should be aware of immunological, allergic and other potential risks associated with the injection of biological substances. On rare occasions, viscoelastic products containing sodium hyaluronate have been observed to become slightly opaque or to form a slight precipitate upon instillation into the eye. The clinical significance, if any, of this phenomenon is not known. The physician should, however, be aware of this possibility, and, should it be observed, the cloudy or precipitated material should be removed by irrigation and/or aspiration. Avoid re-use of the cannula.
Drug Interactions: None currently known.
Adverse Reactions: Biolon is well tolerated in the human eye. Transient rises of postoperative intraocular pressure have been reported in some cases. A causal relationship has not been established between Biolon use and postoperative inflammatory reactions (iritis), corneal edema and corneal decompensation.
Dosage And Administration: Dosage varies with type of surgery. Usually a dose of 0.2 to 0.6 mL is injected into the anterior segment of the eye.
Examples of Surgical Applications: Cataract Surgery: Before lens extraction, Biolon is introduced into the anterior chamber to protect the corneal endothelium and to maintain a deep anterior chamber. Additional amounts may also be introduced before implantation of an intraocular lens, and to coat the artificial lens, the surgical instruments and the corneal surface.
Glaucoma Surgery: Biolon is instilled before the trabeculectomy in order to reconstitute the anterior chamber. At the close of surgery, further instillation of Biolon may be required to achieve good subconjunctiva filtration and to prevent tissue adherences.
Corneal Transplant Surgery: In trepanation of the cornea, the anterior chamber is filled with Biolon. The donor graft should be placed on the surface of the solution and sutured into position. Additional amounts of Biolon may be injected to maintain a deep anterior chamber. Biolon may also be used in the anterior chamber of the donor eye to protect the corneal endothelial cells of the graft prior to trepanation, and to protect the exposed endothelial layer of the donor button during preparation of the recipient eye.
Incompatibilities: Mixing of quaternary ammonium salts such as benzalkonium chloride with sodium hyaluronate solutions results in formation of a precipitate. Biolon should not be administered through a cannula previously used with medical solutions containing benzalkonium chloride.
Availability And Storage: Each mL contains: sodium hyaluronate 10 mg. Nonmedicinal ingredients: disodium hydrogen phosphate, sodium chloride, sodium dihydrogen phosphate and water for injection. Sterile disposable syringes of 0.5 and 1 mL. Store in a cold dark place (2 to 8°C). May be kept at 25°C for up to 1 month. Protect from freezing.
BIOLON Ophtapharma Sodium Hyaluronate Ophthalmosurgical Aid