Common Additives Viscosity-increasing (hardening)agents These excipients are required in the following cases: - when the drug suppresses the melting point of the base and thus reduces its viscosity at 37^circ C - to increase the viscosity of the molten or dispersed suppository base without affecting its melting temperature. Deaggl omerators Drug solubility enhancers Absorption (permeation ) enhancers Antimicrobial preservatives

Certainly! Here is a detailed explanation of the common additives used in pharmaceutical formulations, particularly for suppositories:<br /><br />### Viscosity-Increasing (Hardening) Agents<br />These excipients are added to formulations to increase the viscosity and hardness of the base. They are particularly useful in the following scenarios:<br />- **When the drug suppresses the melting point of the base**: Some drugs can lower the melting point of the suppository base, making it too soft at body temperature ($37^{\circ}C$). Viscosity-increasing agents help maintain the appropriate consistency.<br />- **To increase the viscosity of the molten or dispersed suppository base without affecting its melting temperature**: This ensures that the suppository remains solid at room temperature but melts appropriately at body temperature.<br /><br />Common viscosity-increasing agents include:<br />- **Waxes** (e.g., beeswax, carnauba wax)<br />- **Fatty alcohols** (e.g., cetyl alcohol, stearyl alcohol)<br />- **Glycerol monostearate**<br /><br />### Deagglomerators<br />Deagglomerators are used to prevent the aggregation of particles within the formulation. They ensure uniform distribution of the drug throughout the base, which is crucial for consistent dosing and efficacy.<br /><br />Common deagglomerators include:<br />- **Surfactants** (e.g., polysorbates, sodium lauryl sulfate)<br />- **Disintegrants** (e.g., starch, microcrystalline cellulose)<br /><br />### Drug Solubility Enhancers<br />These additives improve the solubility of poorly soluble drugs, enhancing their bioavailability and therapeutic effect.<br /><br />Common solubility enhancers include:<br />- **Cyclodextrins**<br />- **Polyethylene glycol (PEG)**<br />- **Surfactants** (e.g., Tween 80, Span 20)<br /><br />### Absorption (Permeation) Enhancers<br />Absorption enhancers facilitate the penetration of the drug through biological membranes, improving its absorption and bioavailability.<br /><br />Common absorption enhancers include:<br />- **Fatty acids** (e.g., oleic acid)<br />- **Bile salts** (e.g., sodium taurocholate)<br />- **Surfactants** (e.g., sodium lauryl sulfate)<br /><br />### Antimicrobial Preservatives<br />Antimicrobial preservatives are added to formulations to prevent microbial growth, ensuring the safety and stability of the product during storage and use.<br /><br />Common antimicrobial preservatives include:<br />- **Parabens** (e.g., methylparaben, propylparaben)<br />- **Benzalkonium chloride**<br />- **Sorbic acid**<br /><br />These additives play crucial roles in ensuring the stability, efficacy, and safety of pharmaceutical formulations, particularly suppositories.