GPAT 360

Every year 1-2 questions are asked in the GPAT exams from these general topics of Pharmaceutics. 1. Terms of solubility Descriptive term Volume of solvent in ml per gm of solute Very soluble Less than 1 Freely soluble 1 to 10 Soluble 10 to 30 Sparingly soluble 30 to 100 Slightly soluble 100 to 1000 Very slightly soluble 1000 to 10,000 Practically insoluble More than 10,000 2. Flow characteristics of materials    PROPERTY CHARACTER TYPE OF LIQUID Newtonian Follows Newton’s law Liquids with simple molecules and solid dispersion. Non- newtonian         Dilatancy or shear thickening Shear dependent viscosity. Increase in apparent viscosity with increase in rate of shear. Suspensions with high solid content of small deflocculated particles.       Pseudoplasticity or shear thinning

Tablet Coating  In previous articles, we have seen various excipients used in the tablets, types of tablets and evaluation parameters. Click here to view article on excipients used in the formulation of tablets . Click here to view article on evaluation parameters for the tablets. Click here to view article on types of tablets . In case of formulation of tablets, tablet coating is an important point. Purpose of tablet coating and the excipients and their role is important for the GPAT exam. Tablets are either film coated or sugar coated. In case of film coating, non-enteric coating or enteric coating excipients are used for the various purposes. PURPOSE OF TABLET COATING To mask the taste, color or odor of the drug. To provide physical and chemical protection. To control the release of drug from tablet. To protect the drug from acidic environment of stomach using acid-resistant coating material. A. Sugar coating B. Film coating   I) Coating using non-e

Generally, tablets are classified by their route of administration/function. Primary classification of tablets can be given as follow: I) Tablets ingested orally Standard compressed tablets Multiple compressed tablets Delayed action and enteric coated tablets Film coated tablets Sugar coated tablets II) Tablets used in the oral cavity Buccal and sublingual tablets Troches and lozenges Dental cones III) Tablets administered by other routes Implantation tablets Vaginal tablets IV) Tablets used to prepare solution Effervescent tablets Dispensing tablets Hypodermic tablets Tablet triturates Standard coated tablets Methods of manufacturing: wet granulation, double compaction or direct compression. These tablets usually rapidly disintegrate and releases drug. Drugs intended for local effects in GIT : Tablets contain water insoluble drug. E.g. adsorbents and antacids. Drugs intended to produce systemic effect : Drugs possess some aqueous solubi