Gastro Retentive Microspheres Based Drug Delivery: Formulation and Evaluation

Floating microsphere are gastro- retentive drug delivery system. As the system floats over gastric contents, the drug is released slowly at desired rate resulting in increased gastric retention time. Floating system are low density that have sufficiently bouncy to float over gastric fluid. After release of drug, the residual system is emptied from the stomach. Attempts are being made to develop a drug delivery system which can be provide therapeutically effective plasma drug concentration for longer period thereby reducing the frequency and minimizing fluctuation in plasma drug concentration at steady state by delivering the drug in a sustained manner.

MATERIAL AND METHOD MATARIAL

Ramipril is used as active pharmaceutical ingredients, HPMC K-4M, HPMC K-15M, HPMC K-100M, Ethyl Cellulose, Sodium alginate, Calcium chloride are of standard grade. ?

Table 01: Formula for Ramipril microspheres

U.V Scanning:

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Figure No. 01: UV spectrum of Ramipril

? _max of was found to be 206 nm in 1.2 acidic buffer of P^H 1.2. Hence further study was carried out at 206 nm in p^H 1.2 acidic buffer.

Standard calibration curves:

Table 02: Calibration curves in 0.1 N HCL

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Figure No.02: Calibration curve of Ramipril in 0.1 N HCl

DSC:

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Figure No. 03: DSC of pure drug Ramipril

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Figure No. 04: DSC of formulation

DSC Thermograms of pure Ramipril, blend of polymer with drug were determined. Pure Ramipril showed a sharp onset of peak at 109^o C corresponding to its melting point. There was no appreciable change in the melting endotherms of physical mixture compared to that of pure drug Ramipril. Absence of any new endothermic peak or disappearance or shit of endothermic peak confirms that there is no any interaction and hence the polymers are compatible with drug.

SEM:

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Figure No. 05: Figures of SEM of Microspheres

The microspheres were spherical and the external surface was smooth with slightly rough surface? which could be due to drying. The internal surface of microspheres showed sponge like nature.

Evaluation Of Floating Microspheres For Floating Parameters:

Table 03: %Yield, mean particle size, angle of repose of microspheres

Table 04: entrapment efficiency, in vitro buoyancy, % drug release of ramipril microspheres

Table 05: % Drug release study of ramipril microspheres (f1 ?f5)

Table 06: % drug release study of ramipril microspheres (f6 ? f9)

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Figure No.06: % Release of drug of formulations (F-F3)

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Figure No.07: % Release of drug of formulations (F4-F6)

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Figure No. 08: % Release of drug of formulations (F7-F9)

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