OCOCH3 N(CH3)3 N(CH3)3 OCOCH3 H H3COCO H3)3 N(CH3)3 12. Drugs administrated orally as a solid or in suspension have to dissolve in the aqueous gastric fluid before they can be absorbed and transported via the systemic circulation to their site of action Either by absorption or by direct administration, the drugs's solubility will influence its ease of transport to the body compartments available to that drug 13.(a)Solutions whose properties are linearly proportional to the concentration of the solute are referred to as ideal solutions (b) Polar solute have permanent dipoles and so there are strong electrostatic attractive forces between their particles and the polar water molecules 14.(a)High polar group to carbon atom ratio b) The presence of polar groups that can form hydrogen bond to water molecules and ionize in 15.(a)Form salts that would improve water solubility but would break down to yield the drug in the biological system (b) Introduce water solubilising groups into a part of the structure that is not the pharmac ophone of the drug (c) Formulate as a suitable dosage forn 16. (a) Any method for carboxylic acid, phosphate and sulphonic acid group (b) Any method for basic groups (c) Any method for polyhydroxy and ether residues 17. Structure-activity relationships. These are the general relationships obtained from a study of the changes in the structure of a lead. These changes are used to find or predict the structure with the optimum activityH H N(CH3 )3 H H OCOCH3 N(CH3 )3 H H OCOCH3 H H H H OCOCH3 H N(CH3 ) H 3 N(CH3 )3 H H H3COCO H H 12. Drugs administrated orally as a solid or in suspension have to dissolve in the aqueous gastric fluid before they can be absorbed and transported via the systemic circulation to their site of action. Either by absorption or by direct administration, the drugs’s solubility will influence its ease of transport to the body compartments available to that drug. 13. (a) Solutions whose properties are linearly proportional to the concentration of the solute are referred to as ideal solutions. (b) Polar solute have permanent dipoles and so there are strong electrostatic attractive forces between their particles and the polar water molecules. 14. (a) High polar group to carbon atom ratio (b) The presence of polar groups that can form hydrogen bond to water molecules and ionize in water. 15. (a) Form salts that would improve water solubility but would break down to yield the drug in the biological system. (b) Introduce water solubilising groups into a part of the structure that is not the pharmacophore of the drug. (c) Formulate as a suitable dosage form. 16. (a) Any method for carboxylic acid, phosphate and sulphonic acid groups. (b) Any method for basic groups. (c) Any method for polyhydroxy and ether residues. 17. Structure-activity relationships. These are the general relationships obtained from a study of the changes in the structure of a lead. These changes are used to find or predict the structure with the optimum activity