Closures for Pharmaceutical Preparations: A Review of Design and Test Considerations - The author examines the use of closures for products intended for injection. - BioPharm International

ADVERTISEMENT

Closures for Pharmaceutical Preparations: A Review of Design and Test Considerations
The author examines the use of closures for products intended for injection.


BioPharm International
Volume 25, Issue 12, pp. 32-36

MANUFACTURING PROCESS

The manufacturing process for closures involves processing raw materials and auxiliary substances; weighing and mixing; followed by vulcanization. Vulcanization is a chemical process for converting rubber or related polymers into more durable materials via the addition of sulfur (or another equivalent curative) together with an accelerating agent such as 2-mercaptobenzothiazole; an activator, usually zinc oxide; fillers such as carbon black or limestone; antioxidants; and lubricants. Following vulcanization, molding and compressing occur.

There are two types of molding: compression and injection, of which the former is the most common. Compression molding is a method of molding in which the molding material, generally preheated, is first placed in an open, heated mold cavity. The mold is closed with a top force or plug member, and pressure is applied to force the material into contact with all mold areas, while heat and pressure are maintained until the molding material has cured. Injection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity.

After molding, the stages are: coating, washing, siliconization (if required, using specific, high-viscosity silicon oil), and packaging. Siliconization has several advantages in that it prevents stoppers from sticking together or onto other surfaces and can assist with the insertion of a needle through the stopper. The siliconization step is, however, a potential source of contamination. Silicone used in the preparation of rubber stoppers should meet appropriate quality control criteria and not have an adverse effect on the safety, quality, or purity of the drug product.

The mixing of raw materials and auxiliary substances involves the formulation of the stopper. A stopper is typically made up of 60% rubber, 30% fillers (which protect the physical properties of the rubber) and pigments, 5% plasticizers (which provide flexibility), 5% additional chemicals including accelerators (which help to create the cross-linkages which give the stopper its strength and hardness), activators (which are a function of the efficiency of the cross-linkages), and antioxidants (which help to avoid the degradation of the rubber).

There are different types of rubber, such as natural rubber (latex), isoprene rubber (a chemical copy of natural rubber), styrol-butadine rubber, ethylene propylene dyes monomers, silicone (polysiloxane) rubber, and halogenized butyl rubber.


blog comments powered by Disqus

ADVERTISEMENT

ADVERTISEMENT

FDA Panel Unanimously Backs Secukinumab for the Treatment of Psoriasis
October 22, 2014
Roche to Expand and Improve its Basel Site
October 22, 2014
Pall ForteBio Releases Bioprocessing Contamination Detection Kit
October 22, 2014
EMA Works to Speed Up Ebola Treatment
October 20, 2014
Amgen Sues Sanofi and Regeneron over Patent for mAb Targeting PCSK9
October 20, 2014
Author Guidelines
Source: BioPharm International,
Click here