Physical and chemical properties of drug molecules

Calculation of pH values of aqueous solutions of strong and weak acids and bases 

Dissociation of water Strong acids and bases Weak acids and bases 

Effect of pH on partitioning Drug stability Zero order degradation First order degradation Stereochemistry of drugs Geometrical isomerism 

Profiles of physico-chemical properties of some drug molecules 

Benzyl penicillin 5-Fluorouracil Acebutolol Sulphadiazine Isoprenaline Prednisolone Guanethidine Pyridostigmine bromide Additional problems 

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Chromatographic techniques identify drugs through their physical and chemical properties of the molecule as a whole such as structure and size, whereas spectroscopic tend to identify compounds on the basis of certain parts present within the molecule. Instrumental techniques are used not only in... 

The next term in Eq. (1) that can be manipulated is Cs, the saturation solubility of the drug. This variable can be influenced by both patient and pharmaceutical variables. The patient variables include the changes in PH as well as the amounts and types of secretions along the GIT. Additionally, both the physical and chemical properties of a drug molecule can be modified to increase or decrease its saturation solubility. 

The most commonly used method is to graft cyclodextrins and their derivatives (aza-crown ethers, fullerenes, linear carbohydrate biopolymers and inorganic/organic hybrid networks) onto the textile materials. Cyclodextrins are potential high-performance carrier materials that have the ability to alter physical, chemical and biological properties of drug molecules. This... 

Many complexes and coordination compounds exist as isomers, compounds that contain the same numbers of the same atoms but in different arrangements. For example, the ions shown in (13a) and (13b) differ only in the positions of the Cl ligands, but they are distinct species, because they have different physical and chemical properties. Isomerism is of more than academic interest for example, anticancer drugs based on complexes of platinum are active only if they are the correct isomer. The complex needs to have a particular shape to interact with DNA molecules. 

All drugs are chemicals, and pharmacy is a subject that deals with the study of various aspects of drugs. Therefore, it is needless to say that to become a good pharmacist the knowledge of the chemistry of drugs is essential. Before moving on to the other chapters, let us try to understand some of the fundamental chemical concepts in relation to the physical properties of drug molecules. 

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