Page 21 - Dosage 1-part2 -ebook_Neat

30/10/2025, 00:02 Pharmaceutical Solutions & Sterile Dosage Forms

Syrup (> 65%w/w) will usually protect an oral liquid from growth of most microorganisms
by its osmotic effects.

Parabens:

Usually, a combination of two parabens are used, e.g. methyl and propyl parabens (in a ratio of
9:1) to enhance the antimicrobial spectrum.

Safety for Internal Use of parabens:

The WHO and FDA have evaluated the safety of parabens for internal use and determined
acceptable daily intake (ADI) levels.

For example: Methylparaben and propylparaben are considered safe within regulatory
limits, as they are metabolized into non-toxic compounds (e.g., para-hydroxybenzoic acid)
and excreted.

Examples of Preservatives used in external (topical) solutions:

Chloro-cresol
Chloro-butanol
Para-hydroxybenzoates (parabens)
Ethanol

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