Gastro-Retentive Drug Delivery System, Unit-III, BP704T: NDDS, Sem-VII, Final Year B. Pharm (SPPU 2019P).pptx.pptx

Unit III
Gastroretentive drug delivery systems: Introduction, advantages, disadvantages,
approaches for GRDDS - Floating, high density systems, inflatable and gastroadhesive systems and their applications.

1. GASTRO-RETENTIVE DRUG DELIVERY SYSTEM (GRDDS) Ms. Kartiki M. Bhandari Assistant Professor (Pharmaceutics)

2. UNIT III Transdermal Drug Delivery Systems: Introduction, Permeation through skin, factors affecting permeation, permeation enhancers, basic components of TDDS, formulation approaches. Gastro-retentive drug delivery systems: Introduction, advantages, disadvantages, approaches for GRDDS - Floating, high density systems, inflatable & gastro-adhesive systems & their applications. Naso -pulmonary drug delivery system: Introduction to Nasal & Pulmonary routes of drug delivery, Formulation of Inhalers (dry powder & metered dose), nasal sprays, nebulizers. 2

3. INTRODUCTION TO GRDDS GRDDS is an approach to prolong gastric residence time by remaining in gastric region for prolong period of time, thereby targeting site-specific drug release in the gastric or duodenal parts for local or systemic effects (cancer, inflammation, etc.) GRDDS provide efficient means of enhancing the bioavailability & controlled delivery of many drugs. The popularity of this system is increasing day-by-day due to its easy of manufacturing & cost effectiveness. Hence, GRDDS serves as a valuable tool for the patients who prefer oral route with less frequent dosing. 3

4. NEED / RATIONALE OF GRDDS Drugs that are absorbed from the proximal part of the GIT. Drugs that are less soluble or that degrade at alkaline pH. Drugs that are absorbed due to variable gastric emptying time . Local or sustained drug delivery to the stomach & proximal small intestine to treat certain conditions. Treatment of peptic ulcers caused by H. Pylori infections. 4

5. POTENTIAL DRUG CANDIDATES FOR GRDDS Drugs those are locally active in stomach. Drugs that have narrow absorption window in GIT. Drugs those are unstable in the intestinal or colonic environment . Drugs that disturb normal colonic microbes . Drugs that exhibit low solubility at high pH values & high solubility at low pH values. 5

6. ADVANTAGES OF GRDDS This system offers improved bioavailability . It reduces dose & dosing frequency . This system minimizes fluctuation of drug concentration in blood. This system helps in targeting of drugs. 6

7. ADVANTAGES OF GRDDS Local action can be achieved in GIT. (E.g. Antacids). This system reduces the side effects . Sustained release can be achieved. It is economic as well as safe route of administration. Can be used for wide range of drugs . 7

8. DISADVANTAGES OF GRDDS This system should be administered with plenty of water . Drugs with solubility or stability problem in GIT can’t be administered. Drugs, which undergoes 1 st pass metabolism , are not suitable. (E.g. Nifedipine). Drugs which are irritant to gastric mucosa are not suitable. (E.g. Aspirin & NSAID). Drugs that absorb equally well through GIT . (E.g. Isosorbide dinitrate, Nifedipine). 8

9. APPROACHES IN GRDDS 9

10. APPLICATIONS OF GRDDS 1) Bioavailability: The bioavailability of controlled release GRDDS is significantly enhanced in comparison to the administration of non-GRDDS controlled release polymeric formulations. There are several different processes, related to absorptions & transit of the drugs in GIT, that act concomitantly to influence the magnitude of drugs absorption. 10

11. APPLICATIONS OF GRDDS 2) Site-specific drug delivery system: These systems are particularly advantageous for drugs those are specifically absorbed form intestine GIT (E.g. Furosemide). The controlled, slow delivery of drug to the GIT provides sufficient local therapeutic levels & limits the systemic exposure to the drugs. It reduces the side effects which are caused by the drugs in the blood circulation. In addition, the prolonged gastric availability from a site directed delivery system may also reduce the dosing frequency. 11

12. APPLICATIONS OF GRDDS 3) Sustained drug delivery: In this system, dose is larger & hence it prohibits passing from pyloric opening. New sustained release floating capsules of nicardipine HCl were developed & evaluated in-vivo . Plasma concentration - time curves shows longer duration (16 hrs) in the sustained release floating capsule as compared to conventional capsule (8 hrs). Hydrodynamically balance system can remain in stomach for prolong periods & hence release the drug in sustained manner for prolong period of time. 12

13. APPLICATIONS OF GRDDS 4) Enhancement of absorption: Drugs which are having poor bioavailability because of site-specific absorption from the upper parts of the GIT are potential candidates to be formulated as floating drug delivery systems, thereby maximizing their absorption. By virtue of its floating ability these dosage forms can be retained in the gastric region for prolong period of that drug can be targeted with maximum absorption rate. 13

14. APPLICATIONS OF GRDDS 5) Minimize adverse activity at colon: Retention of the drug in the HBS systems at the stomach minimizes the amount of drug that reaches the colon. Thus, undesirable activities of the drug in colon may be prevented. This pharmacodynamic aspect provides the rationale for GRDF formulation for beta lactam antibiotics that are absorbed only from the small intestine & whose presence in the colon leads to the development of microorganism’s resistance. 14

15. EVALUATION OF GRDDS 15 Time req. for tablet to rise on surface of medium Total time for which tablet remain floating

16. MARKETED FORMULATIONS OF GRDDS 16

17. MARKETED FORMULATIONS OF GRDDS 17

18. ANY QUESTIONS…???