Supersaturation is a condition in which the concentration of the drug in the solution is higher than its solubility. This situation can have a positive effect on increasing the bioavailability of drugs that are poorly soluble in water. To maintain a supersaturated state and prevent precipitation of drugs, various excipients are used, such as polymers, surfactants and cyclodextrins. Hydroxypropylmethylcellulose, which belongs to the group of cellulose polymers, is one of the commonly used precipitation inhibitor. When reviewing the literature, we focused on the effect of hydroxypropylmethylcellulose on prolonging and maintaining the supersaturated state of various drugs, especially those with low solubility, which belong to BCS class II and IV. Predissolved HPMC added to the dissolution medium prolongs and increases the degree of supersaturation of ibuprofen sodium, compared to solid HPMC or formulations without HPMC. The effect of HPMC is particularly pronounced for lipophilic drugs with a higher logP, where it significantly improves absorption and peak plasma concentrations. Different types and concentrations of HPMC can influence the achievement of higher concentrations and degrees of supersaturation of drugs in formulations. Mechanisms such as hydrogen bonding, steric hindrance, viscosity and effect of molecular weight are key in inhibiting precipitation and maintaining the supersaturated state.
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