Tushar D. Fegade

In the current investigation we formulated and evaluates matrix tablet using modified gum of Pistacia lantiscus gum (PLMG) as natural matrix forming agent used in various successively increasing concentration. The pre-compression study of the powder blends of drug, PLMG and other excipients were done by calculating bulk density, tapped density, angle of repose and carr’s index (% compressibility) and hausner’s ratio. The tablets using PLMG as matrix forming agent were prepared by direct compression method and prepared tablets were evaluated for thickness, hardness, weight uniformity, friability and content uniformity and were found according to the official guidelines by pharmacopoeia. The swelling behavior of prepared matrix tablets was studied using for 12 hours at 37 ±0.2 0C, it was fond that the drug to modified gum ratio of 1:2 was found to be optimum swelling with the sustained release of model drug up to 97.12 in matrix tablet formulation. The results revealed, that modified fraction of Pistacia lantiscus gum can be used as a drug release modifier to delay as the rate of drug release of which depended on the amount of gum composition, as the concentration of gum was increased there was sustain the drug release.

Microspheres are free flowing particles ranging from 1-1000u. Microspheres are having wide applications in drug delivery system. They are mainly used for targeted drug delivery of anti-cancer agents, ophthalmic agent and can be used for diagnosis purpose. In this article detail discussion was made on the polymers, preparation methods and applications of microspheres in pharmaceutical dosage form development. General methods of preparation are emulsion techniques, phase separation coacervation techniques, spray drying and spray congealing and solvent extraction, in-situ polymerization etc.  Advantages of microspheres use are targeted drug delivery, optimal therapeutic effects and minimum side effects. Recent trends are floating microspheres, radio immobilization using microspheres. Gastro-retentive floating microspheres are low-density systems that have sufficient buoyancy to float over gastric contents and remain in stomach for prolonged period. The drug is released slowly at desired rate resulting in increased gastric retention with reduced fluctuations in plasma drug concentration.

Colon-specific drug delivery systems (CDDS) are desirable for the treatment of a range of local diseases such as ulcerative colitis, Crohn’s disease, irritable bowel syndrome, chronic pancreatitis, and colonic cancer. In addition, the colon can be a potential site for the systemic absorption of several drugs to treat non-colonic conditions. Drugs such as proteins and peptides that are known to degrade in the extreme gastric pH, if delivered to the colon intact, can be systemically absorbed by colonic mucosa. In order to achieve effective therapeutic outcomes, it is imperative that the designed delivery system specifically targets the drugs into the colon. Several formulation approaches have been explored in the development colon-targeted drug delivery systems. Colon targeting holds a great potential and still need more innovative work. This review article discusses introduction of colon, need and approaches of colonic drug delivery, factor effecting colonic transition, colonic diseases and the novel and emerging technologies for colon targeting.