Glass containers used in pharmaceutical preparations are intended to come into direct contact with pharmaceutical preparations. Glass containers shall have a proper closure system. The containers are designed in a manner that the removal of contents is hassle free and is appropriate to the intended use of the preparation. Glass containers provides a varying degree of protection depending n the nature of the product and the hazards of the environment, and minimizes the loss of constituents. The glass containers used for pharmaceutical packaging shall not interact physically or chemically with the contents in a way that impact the quality of drug products. Various types of glass used for pharmaceutical packaging as per USP are as follows:

  • Type I – borosilicate glass
  • Type II – treated soda-lime glass
  • Type III – regular soda-lime glass
  • Type IV (NP) – general purpose soda-lime glass

Type I borosilicate glass has a high melting point, so it can withstand high temperatures, has high hydrolytic resistance, is resistant to chemical substances, provides reduced leaching action, and can withstand sterilization. Type I borosilicate glass is used for laboratory glass apparatus, water for injection and for parenteral and non-parenteral use.

Type II treated soda-lime glass is fairly resistant to attack by water for a period of time. Sulfur treatment neutralizes the alkaline oxides on the surface, thereby rendering the glass more chemically resistant. It has a high hydrolytic resistance. Type II treated soda-lime glass is used for alkali-sensitive products, infusion fluids, blood and plasma, and large-volume containers.

Type III regular soda-lime glass containers high concentrations of alkaline oxides and imparts alkalinity to aqueous substances, flakes easily, and may crack due to sudden change of temperature. It has a moderate hydrolytic resistance. Type III regular soda-lime glass is used for all solid dosage forms (tablets, powders, and so on) and oily injections.

Type IV (NP) general purpose soda-lime glass is non-parenteral glass. Type NP general purpose soda-lime glass is only used for oral and topical purposes.

The glass is tested using various types of tests such as Glass Grains Test and Surface Glass Test for hydrolytic resistance to determine the glass type.

 

Reference: USP Chapter 660 Containers – Glass