PHS 4601 Lecture Notes - Lecture 6: Ethylenediaminetetraacetic Acid, Tolbutamide, Methylparaben
5 Dec 2017
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Liquid preparations consisting of solid particles dispersed throughout a liquid phase in which the particles are not soluble; limited solubility, not complete insolubility. When the drug cannot be dissolved in certain amount of solvent. When a slow release, slow absorption or extended absorption desired: ex: 1 drug available as solution and suspension (insulin for injection as solution or suspension) Dissolves in the gi tract fluid (expectation) so it doesn"t remain a suspension: can"t be used via iv since particles will block circulation stroke or heart attack. Fine drug particles- very fine powder, our ability to decrease particle size is limited in pharmacy. Certain crystal forms (polymorphism issues) - different solubility/dissolution. Uniformity in size (homogenous, nano size)) as mentioned in first requirement, fine with narrow distribution since effects dissolution, sedimentation rate, etc. Slow sedimentation- suspension is a non-colloidal system and thus not stable difference between particles and media. Easily re-dispersible- since sedimentation cannot be avoided, should redisperse with gentle shaking.
