Pegaptanib is a selective vascular endothelial growth factor (VEGF) antagonist indicated for the treatment of neovascular (wet) age-related macular degeneration. Pegaptanib is an aptamer, a pegylated modified single-stranded oligonucleotide, which adopts a threedimensional conformation that enables it to bind to extracellular VEGF. Pegaptanib specifically binds to the 165 isoform of VEGF, a protein that plays a critical role in angiogenesis (the formation of new blood vessels) and increased permeability (leakage from blood vessels), two of the primary pathological processes responsible for the vision loss associated with neovascular age-related macular degeneration. Pegaptanib is administered in a 0.3 mg dose once every six weeks by intravitreal injection. An intravitreal injection is one that is administered directly into the eye, more specifically, into the vitreous humour, or the jelly-like fluid within the eye.

Нeparin (or Unfractionated heparin ) is an anticoagulant indicated for both the prevention and treatment of thrombotic events such as deep vein thrombosis (DVT) and pulmonary embolism (PE) as well as atrial fibrillation (AF). Heparin can also be used to prevent excess coagulation during procedures such as cardiac surgery, extracorporeal circulation or dialysis, including continuous renal replacement therapy. Heparin administration can be by intravenous (or subcutaneous route. Intravenous heparin is continuously administered for therapeutic anticoagulation, while intermittent subcutaneous administration is used to prevent thromboembolism. Once administered, heparin binds reversibly to antithrombin III (ATIII) and greatly accelerates the rate at which ATIII inactivates coagulation enzymes thrombin (factor IIa) and factor Xa. The heparin-ATIII complex can also inactivate factors IX, XI, XII, and plasmin, but the antithrombotic effect of heparin is well correlated to the inhibition of factor Xa. Typical adverse effects from heparin use include bleeding, thrombocytopenia, injection site reactions, and other adverse effects only seen with chronic heparin administration. Bleeding is a major complication associated with heparin use. Patients should undergo monitoring for new bleeding that may present in the urine or stool. Bleeding may also present as bruising, petechial rash and nosebleeds.

Hyaluronic acid (HA) is a high molecular weight biopolysacharide, discovered in 1934, by Karl Meyer and his assistant, John Palmer in the vitreous of bovine eyes. Hyaluronic acid is a naturally occurring biopolymer, which has important biological functions in bacteria and higher animals including humans. It is found in most connective tissues and is particularly concentrated in synovial fluid, the vitreous fluid of the eye, umbilical cords and chicken combs. It is naturally synthesized by a class of integral membrane proteins called hyaluronan synthases, and degraded by a family of enzymes called hyaluronidases. Hyaluronan synthase enzymes synthesize large, linear polymers of the repeating disaccharide structure of hyaluronan by alternating addition of glucuronic acid and N-acetylglucosamine to the growing chain using their activated nucle¬otide sugars (UDP – glucuronic acid and UDP-N-acetlyglucosamine) as substrates. The number of repeat disaccharides in a completed hyaluronan molecule can reach 10 000 or more, a molecular mass of ~4 million daltons (each disaccharide is ~400 daltons). The average length of a disaccharide is ~1 nm. Thus, a hyaluronan molecule of 10 000 repeats could ex¬tend 10 μm if stretched from end to end, a length approximately equal to the diameter of a human erythrocyte. Although the predominant mechanism of HA is unknown, in vivo, in vitro, and clinical studies demonstrate various physiological effects of exogenous HA. Hyaluronic acid possesses a number of protective physiochemical functions that may provide some additional chondroprotective effects in vivo and may explain its longer term effects on articular cartilage. Hyaluronic acid can reduce nerve impulses and nerve sensitivity associated with pain. In experimental osteoarthritis, this glycosaminoglycan has protective effects on cartilage. Exogenous HA enhances chondrocyte HA and proteoglycan synthesis, reduces the production and activity of proinflammatory mediators and matrix metalloproteinases, and alters the behavior of immune cells. In addition to its function as a passive structural molecule, hyaluronan also acts as a signaling molecule by interacting with cell surface receptors and regulating cell proliferation, migration, and differentiation. Hyaluronan is essential for embryogenesis and is likely also important in tumorigenesis. HA plays several important organizational roles in the extracellular matrix (ECM) by binding with cells and other components through specific and nonspecific interactions. Hyaluronan-binding pro¬teins are constituents of the extracellular matrix, and stabilize its integrity. Hyaluronan receptors are involved in cellular signal transduction; one receptor family includes the binding proteins aggrecan, link protein, versican and neurocan and the receptors CD44, TSG6, GHAP and LYVE-1. The chondroprotective effects of hyaluronic acid, e.g., that it stimulates the production of tissue in¬hibitors of matrix metalloproteineses (TIMP-1) by chondrocytes, inhibits neutrophil-mediated cartilage degradation and attenuates IL-1 induced matrix de¬generation and chondrocyte cytotoxicity have been observed in vitro. Articular chondrocytes cultured in the presence of HA have a significantly greater rate of DNA proliferation and ex¬tracellular matrix production, compared with chon¬drocytes cultured without HA.