The practice of multifunctional excipients is gaining more and more attention as it simplifies the process of drug formulation by substituting the necessity of using mixture of many excipients. The multifunctional excipients are the class of excipients which includes pre-–processed and co-processed excipients and it provides added functionalities to the formulation. Functionality of an excipient is a useful property which helps in manufacturing and improves quality as well as applicability of the material. Researchers have identified that single component excipients may not always give the required results during development and manufacturing of definite API, hence they are concentrating to develop multifunctional excipients which will have improved quality that will fulfil the requirements of the formulation experts in terms of cost. The cost of new excipient development is very high as it demands toxicity studies, hence the industry is now focusing on co-processing of approved materials. The demand for directly compressible co-processed excipients has also increased due to the availability of high-speed tableting machines, time saving in Abbreviated New Drug Application (ANDA), simplified validation and stability of active ingredients. The intention of this review article is to highlight applicability and increasing attention focusing the benefits of co-processed excipients. Their advantages over conventional blend of excipients include development methods, testing and also highlighting their regulatory consideration.

The selective optimization of side activities (SOSA) approach appears to be a promising strategy for lead generation. In this approach old drugs are used to generate new hits or leads. The objective of SOSA is to prepare analogues of the hit molecule in order to transform the observed “side activity” into the main effect and to strongly reduce or abolish the initial pharmacological activity. The idea of taking a molecule with a primary activity in humans and then enhancing a secondary effect through structural changes describes the most common implementation of SOSA. An advantage to starting a drug discovery program with molecules that have already been tested in humans is that those molecules have already satisfied many safety criteria. Such molecules also likely have favourable pharmacokinetic profiles. In the present review different successful examples of SOSA switches are summarized. We hope that the present review will be useful for scientists working in the area of drug design and discovery.

The rate and extent of absorption of a drug from its dosage form is referred to as bioavailability. While bioequivalence between two drug products is attained if their extent and rate of absorption do not relatively differ when administered at the same dose. A bioequivalence study comprises of two or more bioavailability studies which are performed by i) Measurement of active drug substance or its metabolites in the biological fluid; ii) Comparative pharmacodynamic studies in humans; iii) Comparative clinical trials; iv) Comparative in-vitro dissolution studies. The rationale of the study is the monitoring of the pharmacokinetic-pharmacodynamic parameters (AUC, C max ) after administration of the tested drug. This study is not an experimental study but a form of data analysis and reporting of comparative bioavailability studies. The study data obtained is required to be equipped with applications of new drug products as notified in Schedule Y. Cumulatively, it aids in the development of pharmaceutical preparations in the pharmaceutical industry. This review article aims to illustrate the systematic overview of BA/BE study with an emphasis on its experimental aspects like study design, volunteer selection, dosing regimen, sample collection procedures along with a detailed insight on Informed Consent Document, Case Report Form, Trial Master file and the Protocol which collectively form the backbone of the clinical study.