Advantages no polymorphism short interval between softening melting storage at

Advantages no polymorphism short interval between

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Advantages – no polymorphism, short interval between softening & melting, storage at high temperature Water soluble – dissolve slowly Cause irritation because take up some water and cause dehydration of mucosa Melting temperature much higher than body temperature i.e. PEG o Can blend several to get the right melting range o Incompatible with many drugs o Common for vaginal administration i.e. glycerin – causes defecation reflex and don’t get any drug absorption Formulation Factors Particle size – small (< 180 microns) to prevent irritation and consider solubility Don’t worry about particle size if drug and base are incompatible Presence of water – oxidation, hydrolysis, may need preservative, could precipitate if evaporates Viscosity – matters in the mold so you don’t get settling; low = BAD Hygroscopicity – if they absorb water, they dissolve; extra careful with these Rate of drug release – depends on liquefaction and solution times & hydrophilicity/hydrophobicity of the drug Brittleness – can be broken if they arne’t good or don’t have enough water Volume contraction – contract at low volumes Incompatibilities – many incompatible in PEG or crystallize in other bases Rancidity/antioxidants Antimicrobial preservative – add if aqueous phase is present Density – calculate with density factor and cocoa butter being the average
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