Packaging of pharmaceuticals || Glass || pharmaceutics in packaging of pharmaceuticals Glass

 

PACKAGING OF PHARMACEUTICALS

Glass:

Glass is commonly used in pharmaceutical packaging because it possesses superior protective qualities, it is economical, and containers are readily available in a variety of sizes and shapes.

It is essentially chemically inert, impermeable, strong, and rigid, and has FDA clearance.

Glass does not deteriorate with age, and with a proper closure system, it provides an excellent barrier against practically every element except light.

Colored glass, especially amber, can give protection against light when it is required.

The major disadvantages of glass as a packaging material are its fragility and its weight.

Barrier against all elements except light Composition of glass: Glass is composed principally of sand, soda-ash, limestone, and cullet.

Sand - is pure silica Soda ash-NaCO₃

Lime stone-CaCO₃

Cullet-Broken glass (Fusion agent)

Most common anions and cations in glass are: only one anion in glass

Oxygen: only one anion in glass

Presence of NO⁺: chemically resistant for glass, melting of glass is possible

Boron oxide increases melting point.

Lead: provide clarity and Brilliance,

Al₂O₃: increases hardness and durability, increases chemical resistance

Manufacturing Process of Glass:

Blowing

Blowing uses compressed air to form the molten glass in the cavity of a metal mold.

Most commercial bottles and jars are produced on automatic equipment by this method.

Drawing

In drawing, molten glass is pulled through dies or rollers that shape the soft glass.

Rods, tubes, sheet glass, and other items of uniform diameter are usually produced commercially by drawing.

Ampuls, cartridges, and vials drawn from tubing have a thinner, more uniform wall thickness, with less distortion than blow-molded containers.

Pressing

In pressing mechanical force is used to press the molten glass against the side of a mold.

Casting uses gravity or centrifugal force to cause molten glass to form in the cavity of the mold.

Amber glass and red glass:

Protect from light by screening out harmful ultraviolet rays.

The USP specifications for light-resistant containers require the glass to provide protection against 2900 to 4500 angstroms of light.

Amber glass meets these specifications. but the iron oxide added to produce this color could leach into the product.

Therefore, if the product contains ingredients subject to iron-catalyzed chemical reactions, amber glass should not be used.

Glass for Drugs

Powdered glass (Performed on crushed Grain) test is done for Type 1 whereas water attack test is used for evaluating the whole containers for Type 11 glass that has been exposed to SO₂ fumes

Type-I: Borosilicate glass more chemically resistant than other

Type-II: Treated soda lime Glass

Type-III: Regular soda lime Glass

Type NP: General purpose soda lime Glass for oral or topical use, i.e., non-parenteral.

Type-I: Borosilicate:

In this highly resistant glass, a substantial part of the alkali and earth cations are replaced by boron and/or aluminum and zinc.

It is more chemically inert than the soda-lime glass, which contains either none or an insignificant amount of these cations.

Although glass is considered to be a virtually inert material and is used to contain strong acids and alkalis as well as all types of solvents, it has a definite and measurable chemical reaction with some substances, notably water.

The sodium is loosely combined with the silicon and is leached from the surface of the glass by water.

Distilled water stored for one year in flint type III glass (to be described) picks up 10 to 15 parts per million (ppm) of sodium hydroxide along with traces of other ingredients of the glass.

The addition of approximately 6% boron to form type 1 borosilicate glass reduces the leaching action, so that only 0.5 ppm is dissolved in a year.

Type II-Treated Soda-Lime Glass.

When glassware is stored for several months, especially in a damp atmosphere or with extreme temperature variations, the wetting of the surface by condensed moisture (condensation) results in salts being dissolved out of the glass.

This is called “blooming” or “weathering”, and in its early stages, it gives the appearance of fine crystals on the glass.

At this stage, these salts can be washed off with water or acid Type II containers are made of commercial soda-lime glass that has been de- alkalized, or treated to remove surface alkali.

The de-alkalizing process is known as "sulfur treatment" and virtually prevents -weathering" of empty bottles.

The treatment offered by several glass manufacturers exposes the glass to an atmosphere containing water vapor and acidic gases, particularly sulfur dioxide at an elevated temperature.

This results in a reaction between the gases and Some of the surface alkali, rendering the surface fairly resistant, for a period of time, to attack by water.

The alkali removed from the glass appears on the surface as a sulfate bloom, which is removed when the containers are washed before filling.

Sulfur treatment neutralizes the alkaline oxides on the surface, thereby rendering the glass more chemically resistant.

Type III-Regular Soda-Lime Glass

Containers are untreated and made of commercial soda-lime glass of average or better-than- average chemical resistance.

Type NP-General-Purpose Soda-Lime Glass

Containers made of soda-lime glass are supplied for non-parenteral products, those intended for oral or topical use.