Glass can be classified into different types based on USP criteria.
Parameters:
(1) composition
(2) intended use
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Composition
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Intended Use
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Suitable for Parenteral Drugs
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USP Type
|
|
borosilicate
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aqueous solutions, sterile solutions
|
Yes
|
I
|
|
soda-lime, treated (exposure to sulfur dioxide fumes)
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buffered aqueous solutions with pH < 7.0
|
Yes
|
II
|
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soda-lime glass, untreated
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dry powders, oily or greasy (oleaginous) materials
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possibly
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III
|
|
soda-lime glass, general purpose
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tablets, oral solutions, oral suspensions, ointments, external liquids
|
No
|
NP
|
where:
• NP = nonparenteral
• Soda-lime glass is composed primarily of calcium oxide, silica and soda (sodium hydroxide)
• NP and Type III glass have limited resistance to heat shock and cannot be autoclaved.
Features of the glass:
(1) temperature range (best for borosilicate glass or soda-lime with increased silica)
(2) chemical resistance (greatest for borosilicate glass, least for NP)
(3) nonreactivity with contents
(4) breakage resistance
(5) expansion coefficient
(6) color
(7) opacity
(8) cost (higher for more desirable qualities)
