Hey This is karan Kashyap. Post graduate in pharmacy. I published this PPT for education purpose and you get other ppt also on this side . Thanks

1. BY:
Kamya Varshney
Karan Kashyap
M. Pharm (Pharmaceutics)
Sem – I
NIET Pharmacy Institute
Greater Noida

4. PHARMACEUTICAL FACTORS:
 DENSITY OF DOSAGE FORM
 SIZE OF DOSAGE FORM
 SHAPE OF DOSAGE FORM
 FORMULATION TYPE
PHYSIOLOGICAL FACTORS:
 FED OR UNFED STATE
 NATURE OF MEAL
 CONCOMITANT DRUG ADMINISTRATION
 MIGRATION MOTOR COMPLEX
 FEEDING FREQUENCY
PATIENT RELATED FACTORS:
 GENDER
 AGE
 POSTURE
 DISEASE CONDITION
FACTORS AFFECTING GASTRO-RETENTIVE
DRUG DELIVERY SYSTEMS (GRDDS)

5. DENSITY OF DOSAGE FORM
Dosage form should have density less than that of the gastric fluid (1.004 gm/ml).
SIZE OF DOSAGE FORM
Dosage form with a diameter of more than 7.5 mm shows more gastric residence time
but it should not be more than 9.9mm.
SHAPE OF DOSAGE FORM
Tetrahedral shaped dosage form remains for a longer period in stomach than other
devices of similar size.
FORMULATION TYPE
For the successful design of GRDDS, it is important to understand the role of
excipients and polymers on various types of GRDDS.
For instance, in the mucoadhesive system, polymers with high mucoadhesion
strength, such as carbopol and hydroxypropyl methylcellulose (HPMC), may be
required for successful design of the mucoadhesive dosage form.
Likewise, with the expandable system, polymers with high swelling properties are
more desirable.

6. FED OR UNFED STATE
During fasting, the gastrointestinal motility shows periods of strong motor
activity at intervals of 1.5-2 hours.
NATURE OF MEAL
Motility pattern of the stomach changes to a fed state due to intake of
indigestible polymers or fatty acids. This reduce the gastric emptying rate and
prolongs the drug release.
CONCOMITANT OF DRUG ADMINISTRATION
Anticholinergic drugs (e.g., atropine and propantheline) and Opiates (e.g.,
codiene) can extend GRT.

8. FEEDING FREQUENCY
The frequency of ingested food has an impact on MMC, the gastric residence
time as well.
When a single meal is ingested, the MMC is higher leading to decrease in
gastric residence time. However, when the mean is taken sequentially the
GRT is increases by 6-7 has as the MMC is delayed.
GENDER
A recent study reported that gender affected the gastric emptying time and
intraluminal pH 5.3 influences could explain the longer GRT in females than
in males.
Another study showed that males secreted more gastric acid as compared to
that of females.
AGE
The age of the patient also affects the GRT. Elderly patients have a longer
GRT compared to younger patients.

9. POSTURE
The GRT is dosage forms. In the upright position, the floating system floats
influenced by posture, and the effect is different for floating and non-floating
in the gastric fluid for a prolonged amount of time which can eventually
increase the GRT. However, in similar conditions, the non-floating system
remains in the lower part of the stomach and the gastric emptying rate is
faster as a result of peristaltic contractions. In contrast, in the supine position,
the non-floating system has a longer GRT compared to the floating system.
DISEASE CONDITION
The nature of a patient's a prolonged GRT that is frequently accompanied by
constipation. Likewise, in diabetic patients, GRDDS. It was reported that a
decrease in gastric emptying rate was observed in patients suffering from
depression, whereas an increased rate was observed in patients experiencing
anxiety.

12. References:
1.Lopes, C.M.; Bettencourt, C.; Rossi, A.; Buttini, F.; Barata, P. Overview on
gastroretentive drug delivery systems for improving drug bioavailability. Int.
J. Pharm. 2016, 510, 144-158. [PubMed]
2. Rouge, N.; Buri, P; Doelker, E. Drug absorption sites in the gastrointestinal
tract and dosage forms for site-specific delivery. Int. J. Pharm. 1996, 136,
117-139. [CrossRe]