پديد آورندگان :
Barzegar-Jalali Mohammad نويسنده , Siyahi-Shadbad Mohammad Reza نويسنده , Barzegar-Jalai Azim نويسنده , Adibkia Khosro نويسنده , Mohammadi Ghobad نويسنده , Aghai Behnaz نويسنده , Zeraati Mahdi نويسنده
چكيده لاتين :
Hard gelatin capsule filled with acetaminophen, osmotic agent (sorbitol), a
release promoter (sodium dodecyl sulfate), coated with a semipermeable cellulose
acetate membrane containing a hydrophobic plasticizer (castor oil) and sealed with
white bees wax plug was designed. When placed in the sink water penetrates the
membrane, dissolves the osmotic agent and increases the osmotic pressure inside
the capsule. The increased osmotic pressure enhances the water imbibition and
consequently increases the hydrostatic pressure inside the capsule and when the latter
pressure is high enough it expels out the plug and the drug release commences. With
cellulose acetate concentration constant in membrane forming solution, 11% (w/w),
the factors affecting the onset of the drug release, i.e. the lag time (tL), were
thickness of semipermeable membrane (0.033-0.112 mm) and plug thickness (2.40-
3.40 mm) although the influence of semipermeable membrane thickness was more
important than plug thickness in delaying the onset of release. As the statistical
analysis revealed, castor oil concentrations in the range of 3-4% (w/w) did not affect
the lag time. With the control of the membrane thickness, the onset of release
could be adjusted from 2 to 7 h. The formulations with tL of 3.9 and 5.8 h may have
practical benefits in that if such systems are administered simultaneously with
conventional forms the 6 and 4 times daily drug dosage frequency would be reduced
to 3 and 2 times regimens, respectively. Atheoretical justification was provided for
the observed nonlinear relationship between the onset and/or tL of drug release and
thickness of the semipermeable membrane. After the lag time, the drug release from
the systems conformed to the USP requirements.