Tablet in Tablet - An Innovative and Pragmatic Approach in Tableting Technology

Abstract

Tablets are the most widely used formulation amidst all dosage forms as its convenient to intake, offer precise
dosing and, have low cost. Functionally, compressed tablets can be categorized into simply compressed tablets,
coated and multiple compressed tablets. Further, multiple compressed tablets can be classified as layered
tablets and tablet in tablet dosage form. Among these, tablet in tablet technology is an innovative and pragmatic
approach, where a tablet is compressed with a core tablet in the center. Moreover, the inlay tablet is also a form
of tablet in tablet where the top surface of the core tablet is completely exposed within the outer tablet. tablet in
tablet technology offers various advantages over conventionally coated tablet formulations. There is, no water
penetration into the core tablet hence, no core softening occurs, no seal coat is required over the core tablet.
Incompatible API’s can be formulated into a single tablet by physically separating them. Drug deterioration can
be curtailed down by incorporating sensitive API into a core tablet, thus preventing environmental degradation.
It also prevents drug degradation in the gastric environment, helpful in concealing the bitter and unpleasant taste
of the drug, despite this, the technology has some minor disadvantages like improper centration which may cause
fragile edges, and low-density drug substances in the core may lead to inappropriate formulation size. There
are certain considerations to be taken while developing formulation in tablet in tablet dosage form. Ideally, the
weight of outer tablet granules must be kept twice in weight to that of a core tablet. The core tablet must be kept
as small as possible. The outer tablet granules must possess cohesiveness and plasticity to produce a physically
stable formulation. There are various Machines available to manufacture tablet in tablet formulation, namely, the
Colton Model 232 and the Strokes model 538, Manesty Drycota, etc. There are many formulations developed as
well as approved patents using tablet in tablet technology whereby it replaces conventional coating techniques,
overcoming incompatibility, and stability issues. This review is an attempt to congregate and present meaningful
insight to this revolutionary technology.