ISO 10340-1995 PDF

Full title and description

ISO 10340:1995 — Optics and optical instruments — Contact lenses — Method for determining the extractable substances. This International Standard specified a Soxhlet extraction‑based analytical procedure to quantify substances extractable from contact‑lens materials; the publication has been withdrawn and its content incorporated into later contact‑lens physicochemical test standards.

Abstract

Specifies an analytical method for the quantitative determination of substances extractable from contact lenses by Soxhlet extraction with specified solvents. Extracts may then be examined by chromatographic, spectrophotometric or wet‑chemical techniques to identify residual monomers, cross‑linking agents and catalysts used during polymerization. The method was intended to support material evaluation and pre‑clinical testing of contact‑lens materials.

General information

• Status: Withdrawn.
• Publication date: 1995-07 (July 1995).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 11.040.70 (Optics and ophthalmic instruments).
• Edition / version: Edition 1, 1995.
• Number of pages: 5 (as listed on the ISO bibliographic entry).

Scope

Defines a laboratory procedure using Soxhlet extraction to determine the mass of extractable substances from contact‑lens materials and provides normative references and guidance for subsequent chemical examination of the extracts. The standard focuses on method consistency (solvents, extraction time, drying to constant mass) so results can inform material purity assessment and pre‑clinical evaluation programmes.

Key topics and requirements

• Use of Soxhlet extraction with specified organic solvents and laboratory‑grade reagents.
• Drying procedures and mass‑loss calculation to quantify extractables.
• Examination of extracts by chromatographic, spectrophotometric or wet‑chemical methods to identify residual monomers, cross‑linkers and catalysts.
• Reference to good laboratory practice (GLP) and relevant normative documents (for example ISO 3696 for water quality).
• Requirements for reporting deviations from the method and for clear documentation of test conditions.

Typical use and users

Used by analytical and materials laboratories, contact‑lens manufacturers, research groups developing new lens polymers, and regulatory or conformity assessment bodies performing pre‑clinical material assessments. The procedure supports material safety and quality dossiers by quantifying potentially leachable constituents.

Related standards

ISO 10340:1995 was withdrawn and its content was incorporated into the ISO 18369 series for contact lenses — specifically into ISO 18369‑4 (Physicochemical properties of contact lens materials). The ISO 18369‑4 documents (2006 and the later 2017 edition) now contain the current, consolidated physicochemical test methods for contact‑lens materials. National/adopted versions (EN/SS/BS etc.) reflect these revisions.

Keywords

Contact lenses; extractable substances; Soxhlet extraction; lens materials; residual monomers; ophthalmic optics; ISO 10340; physicochemical testing.

FAQ

Q: What is this standard?

A: ISO 10340:1995 is an International Standard that defined a laboratory method for determining the quantity of substances extractable from contact‑lens materials using Soxhlet extraction.

Q: What does it cover?

A: It covers the extraction procedure (solvents, apparatus, extraction time), drying and mass determination to calculate extractable fraction, and indicates approaches for chemical analysis of extracted material (chromatography, spectrophotometry, wet chemistry). It also references applicable laboratory practice and normative documents.

Q: Who typically uses it?

A: Analytical laboratories, contact‑lens manufacturers and material researchers use the method for material purity and safety assessments; regulatory reviewers and conformity assessment bodies use results from these tests when evaluating new lens materials.

Q: Is it current or superseded?

A: ISO 10340:1995 has been withdrawn. Its test content was incorporated into the ISO 18369 series (notably ISO 18369‑4), which has been revised since 2006; the 2017 edition of ISO 18369‑4 is the consolidated current reference for physicochemical testing of contact‑lens materials.

Q: Is it part of a series?

A: Yes — contact‑lens test methods are now managed under the ISO 18369 series (Ophthalmic optics — Contact lenses), where Part 4 covers physicochemical properties including extraction methods that superseded ISO 10340.

Q: What are the key keywords?

A: Contact lenses; extractables; Soxhlet; physicochemical properties; residual monomers; ISO 10340; ISO 18369.