Introduction

vet004

Company name: Bayer plc

Address: Animal Health Division

Bayer House, Strawberry Hill,

Newbury

Berkshire RG14 1JA

Telephone: 01635 563000

Fax: 01635 563622

Email: animal.health@bayerhealthcare.com

Website: www.bayer.co.uk/products/animalhealth.html

Presentation

Hyonate is a colourless liquid containing 10 mg/ml sodium hyaluronate in physiological sodium chloride phosphate buffer, the pH of which is adjusted to between 6.5 and 8.0.

Uses

For the treatment of lameness in horses due to non-infectious inflammation of joints.

Dosage and administration

For intravenous or intra-articular use.

The recommended dose is:

Intravenous administration	4 ml (corresponding to 40 mg a.i)
Intra-articular administration	2 ml (corresponding to 20 mg a.i)

Treatment may be repeated at weekly intervals for a total of three treatments.

Strict aseptic technique should be observed when injecting Hyonate. As with any intra-articular procedure, proper injection site disinfection and animal restraint are very important.

Excess synovial fluid should be aseptically removed prior to articular injection. Care should be taken not to scratch the cartilage surface with the point of the injection needle. Diffuse swelling lasting 24 to 48 hours may result from movement of the needle while in the joint space.

For best results, the horse should be given three days stable rest after intra-articular treatment before gradually resuming normal activity.

Use during pregnancy and lactation

The product may be used safely in pregnant and lactating animals.

Contra-indications, warnings, etc

This product does not contain an antimicrobial preservative. Any solution remaining in the vial following withdrawal of the required dose should be discarded.

In very rare cases, horses may show a transient flare reaction after intra-articular injection.

This may present as a diffuse swelling lasting 24-48 hours resulting from irritation by the needle while in the joint space. These may be acute but will generally resolve without sequelae within a few days.

Consumer Safety

Withdrawal period(s) - Meat: zero days; Milk: not applicable

Environmental Safety

Any unused product or waste material should be disposed of in accordance with national requirements.

Pharmaceutical precautions

Do not store above 25°C.

Protect from direct sunlight.

Any solution remaining in the vial following withdrawal of the required dose should be discarded.

Legal category

POM-V

Packaging Quantities

2 ml of solution in a clear Type I glass vial with a grey butyl rubber stopper, Teflon face with an aluminium overseal and plastic cap.

Further information

Sodium hyaluronate is a saccharide biopolymer with a key role in maintaining normal joint function. It also has anti-inflammatory properties.

Hyonate is extracted from the capsule of a selected micro-organism and purified to produce an ultra pure form of sodium hyaluronate which is essentially free of protein or nucleic acids. The solution is pyrogen free and sterile. It contains no preservative.

Hyaluronic acid forms the basis of a wide range of saccharide biopolymers (glycosaminoglycans or mucopolysaccharides) consisting of repeating disaccharide units of N-acetyl-D-glucosamine and D-glucuronic acid linked by beta 1-3 and beta 1-4 glycosidic bonds. It is a component of all mammalian connective tissue and therefore widely distributed in body tissues and intercellular fluids. Sodium hyaluronate is the naturally occurring sodium salt of hyaluronic acid. In the normal joint sodium hyaluronate is synthesised by synoviocytes. The resulting long chains form a three dimensionally cross linked network and are the crucial determinant of the properties of the synovial fluid.

The high affinity of sodium hyaluronate for water, which is enclosed rather than bound within the three dimensional structure, is responsible, in particular, for the known high viscosity of the synovial fluid. Recent studies have shown that sodium hyaluronate exerts its lubricant effect primarily on the membrane separating the synovial fluid from the soft tissue (capsule) of the joint which has more powerful retarding action than the joint surfaces. This is explained by the fact that the viscous sodium hyaluronate molecules pass directly from the intercellular space of the synovial membrane into the synovial fluid, thus forming an elastic, fluid transition from capsule to join cavity.

Sodium hyaluronate therefore has various properties:

* it improves the viscosity of the synovial fluid through its 3-dimensional structure (lubrication)

* it assists the filtering function of the synovial membrane (regulation of composition of synovial fluid)

* it is a constituent of hyaline cartilage

* it plays a role in the supply of nutrients to the cartilage.

Sodium hyaluronate also exerts an anti-inflammatory action.