Pompe osmoticheCome sistemi a rilascio modificato

Pompe osmotiche

osmosi

Pompe osmotiche

Farmaco + agente osmoticamente attivo

Il rivestimento della membrana rigida ha un piccolo orifizio (250micron)

Membrana rigida semipermeabile!!!!

Acetato di cellulosa

Pompe osmotiche

Questo tipo di sistema ha l’aspetto di una normale compressa rivestita

la differenza di concentrazione tra interno ed esterno (MEMBRANA SEMIPERMEABILE)

determina un flusso di acqua verso dentro

In contatto con i liquidi acquosi:

La pressione che si determina all’interno della compressa provoca la fuoriuscita attraverso l’orifizio della soluzione del farmaco

Agente osmotico

Oppure:

• Il farmaco stesso è l’agente osmoticamente attivo (pompe di KCl)

• di solito sono p.a. solubili

Semipermeable membrane must possess certain performance criteria:

oIt must have sufficient wet strengthoIt should be selectively permeable to wateroIt should be biocompatible.

The unique feature of semipermeable membrane utilized for an osmotic pump is that it permits only the passage of water into the unit, thereby effectively isolating the dissolution process from the gut environment.

MEMBRANA SEMIPERMEABILE

la cinetica di rilascio è di ordine ZERO!!!

PRODUCT active CONCENTRATION

EFIDAC 24

Pseudoephedrine HCl

Pseudoephedrine 60 mg IR, 180 mg CR

EFIDAC 24

clorpheniramine

Clorpheniramine

maleate

4 mg IR, 12 mg CR

POMPE OSMOTICHE ELEMENTARI

PEG + HPMC

SISTEMA PUSH-PULL

1

2

3

4

SISTEMA PUSH-PULL

PRODUCT active CONCENTRATION

ADALAT OROS

PROCARDIA XL

CALAN SR

COVERA SR

TECZEM

Nifedipine

NIfedipine

Verapamile

Verapamile

Diltiazem-Enalapril

30 mg, 60 mg

30 mg, 60 mg

120 mg, 180 mg, 240 mg

180 mg, 240 mg

180 mg - 5 mg

GLUCOTROL XL Glipizide 2.5 mg, 10 mg

DYNACIRC CR Isradipine 5 mg,10 mg

DITROPAN XL Oxybutinin chloride 5 mg, 10 mg

CARDURA XL Doxazosine 4 mg, 8 mg

ALPRESS LP Prazosine 2,5 mg, 5 mg

TEGRETOL XR Carbamazepine 100 mg, 200 mg, 400 mg

ADVANTAGES OF OSMOTIC DRUG DELIVERY SYSTEMS

delivery rate - zero-order kinetics (which is most desirable)

Delivery may be delayed or pulsed, if desired (CON POMPE OSMOTICHE SOFISTICATE).

For oral osmotic systems, drug release is independent of gastric pH and hydrodynamic conditions which is mainly attributed to the unique properties of semipermeable membrane (SPM) employed in coating of osmotic formulations

Higher release rates are possible with osmotic systems compared with conventional diffusion-controlled drug delivery systems.

The release rate of osmotic systems is highly predictable and can be programmed by modulating the release control parameters.

A high degree of in vivo–in vitro correlation (IVIVC) is obtained in osmotic systems because the factors that are responsible for causing differences in release profile in vitro and in vivo (e.g., agitation, variable pH) affect these systems to a much lesser extent.

The release from osmotic systems is minimally affected by the presence of food in the gastrointestinal tract (GIT).

Production scale up is easy.

DISADVANTAGES OF OSMOTIC DRUG DELIVERY SYSTEMS

Toxicity due to dose dumping.

Additional patient education and counseling is required.

Hypersensitivity reaction may occur after implantation (POMPE OSMOTICHE IMPIANTO).

Tablet splitter

patient education