FORMULATION APPROACHES FOR GASTRORETENTIVE DRUG DELIVERY SYSTEM

SARDAR BHAGWAN SINGH P.G. INSTITUTE OF BIO MEDICAL SCIENCES AND RESEARCH, BALAWALA, DEHRADUN, UTTARAKHAND

PRESENTED BY- GUIDED BY- NAMAN PANT Mrs. GAURI KUKRETIM.Pharm. (Pharmaceutics) Assistant professor

ORGANIGATION-• Introduction

• Anatomy of stomach

• Factors affecting gastric retention

• Formulation Approaches

•Advantages and disadvantages

•Evaluation of gastro retentive drug delivery system

•Marketed formulations

•Conclusion

•References

INTRODUCTION-

DEFINITION-o These are the drug delivery systems which posses

the ability of retaining the drug in the GIT particularly in the stomach for prolonged period of time.

o After the drug release for required time period the dosage form should get degraded without causing any gastric disturbance.

(1) Rohilla Ankur et al, International research journal of pharmacy,2(5),2011,Pp72-78

Anatomy of stomach-

Article in expert opinion on drug delivery, Research gate,DOI:10.1517/17425.247.2011

Factors affecting gastric retention-Size and shape of dosage form

Density

Patient age, body weight, and body

postureDisease state

Fasting and fed condition of

patient

(1) Vyas SP, Khar RK, Controlled drug delivery, Vallabh prakashan, ed(2),2012, Pp199-201(2) Research gate, article in expert openion on drug delivery, DOI:10.1517/174.25247.2011

Formulation approaches-

Floating system

Swelling

Expending

Modified shape systems

Tetrahedron

Round shaped device

Bioadhesive system

High densit

y system

(1)Makwan A, Sameja K, Journal of drug delivery and therapeutics,2012,2(3),P.p12-21(2) Garg R, Gupta GR, Tropical journal of pharmaceutical research,september2008,7(3),P.p1055-

1066(3) Mohamad HG,FurquanNK, International journal of health research, march2009,2(1),P.p33-54

Floating systems-The system which have bulk density lower then the gastric

content is called Floating drug delivery system.They have the potential for continuous release of drug and

remain buoyant in the stomach for a prolonged period of time.

Types

Hydrodynamically balanced system

Gas generating system

Expendable systems-

It is small enough to swallowed. After coming into contact with the gastric fluids, they get expended to a larger size so that gastric retention is achieved.

(1) Research gate, article in expert openion on drug delivery, DOI:10.1517/174.25247.2011

Gas generating systems-

These formulation contain carbonates or bicarbonates which generates CO2 due to their reaction with gastric acid.

Floating microspheres-Solvent evaporation methodSolvent diffusion method

Yeoce PG, Shagufta K, Patel AF, Indian journal of pharmaceutical science, 2005, 67(3), P.p 265-272

RAFT forming system-Systems consists of some gel forming agents. Eg- Sodium

alginate solution containing carbonate or bicarbonate.These systems produce a layer on the top of the gastric

fluids.

(1) Vyas SP, Khar RK, Controlled drug delivery, Vallabh prakashan, ed(2),2012, Pp199-215

Super porous hydrogels-Pore size between 10nm-10µm.They swell to larger size and can withstand pressure with

gastric contraction and due to this larger size their passage through pyloric sphincter is prevented.

1)Makwan A, Sameja K, Journal of drug delivery and therapeutics,2012,2(3),P.p12-21

Bioadhesives-In these systems the dosage form will stick to the mucosal

surface in the gastrointestinal tract as a result of which prolonged gastric retention can be achieved.

Vyas SP, Khar RK, Controlled drug delivery, Vallabh prakashan, ed(2),2012, Pp211-215

Advantages-Improved drug absorption, because of increased gastro retention time of

drug.

Delivery of drug for local action in the stomach.

Reduce cost of drug and better patient compliance.

Reduction of over dose and minimize side effects

1)Makwan A, Sameja K, Journal of drug delivery and therapeutics,2012,2(3),P.p12-21(2)Garg R, Gupta GR, Tropical journal of pharmaceutical research,september2008,7(3), P.p

1055-1066

Disadvantages-

Dose dumping

Poor In Vitro – In Vivo correlation

Patient variation

Limitations-They require a sufficient level of fluids in the stomach for buoyancy

Not feasible for those drugs that have solubility and stability problems in GI fluid.

Drugs that are irritant to gastric mucosa are not suitable for GRDDS.

Evaluation of gastroretentive drug delivery system-

General tests

• Hardness• Friability• Weight variation• Content uniformity• Dissolution• Drug release

Buoyancy time • Buoyancy lag time• Buoyancy duration

Swelling studies

• %Swelling index= Wo-(Wi+Wo)͟͟/Wi×100

• Where, Wo= wt. of swollen tablet with OHP sheet

• Wi= Wt. of initail tablet• Wb= Wt. of OHP paper

Chaturvadi K, Umadevi S, Vaghani S, Scientica pharmaceutica,Scipharma2010,78:927-939

Marketed formulations-Microspheres

• Griseofulvin

• Ibuprofen

• Tranilast

Capsules

• Diazepam

• Furosemide

• Misoprostol

• Propranolol

Tablets

• Atenolol

• Ampicillin

• Fluorouracil

• Prednisolone

Some commercial Gastroretentive Drugs-Company Product Drug

Ranbaxy Cifran OD Ciprofloxacin

GSK Gaviscon liquid Antacid

Cipla Ciplox OD Ciprofloxacin

Sanofi Xatral OD Alfuzosin

Fabre Topalkoun Antacid

Baya Cipro XR Ciprofloxacin

Bristol Myers Squibb Kombiglyze XR Matformin

(1) Research gate, article in expert openion on drug delivery, DOI:10.1517/174.25247.2011

Conclusion-Gastroretentive drug delivery systems are the most

preferable systems in order to deliver the drugs which have a narrow absorption window near the gastric region. Now a days a number of drug delivery devices are being developed which aim at releasing the drug at gastric region. Even though these drug delivery systems have several advantages they also have disadvantages like their invitro-invivo correlation is very less.