Abstract:
Acarbose is a well-known synthetic drug, which commonly treats type II diabetes. For diabetic
patients, acarbose must be administered multiple doses a day to keep a stable glucose level in the
body due to short biological half-life. Therefore, drug formulations with sustained releasing
properties are developed using stable carriers like, Montmorillonite (MMT) due to its unique
structure and properties. In this study, acarbose intercalated clay formulations were synthesized and
their sustained releasing properties tested. Acarbose solution (100 ppm) was stirred with MMT (1 g)
for 24 h at 4–8 pH. The highest intercalation of acarbose was observed at acidic pH due to
electrostatic interactions between negatively charges clay layers and protonated acarbose molecules.
The concentration of acarbose in aqueous solution was determined using the UV-Vis spectroscopy
method. The calibration curve (2–40 ppm) of standard acarbose (r2 =0.9826) at 426 nm, was used for
calculating the acarbose intercalation percentages. 2.18 mg g-1 (43.77%) and 5.1 mg g-1 (52.27%) of
acarbose intercalated into MMT at pH 6 and the interlayer space of unmodified montmorillonite has
been increased from 1.185 to 1.310 nm and 1.403 nm upon acarbose intercalation at 50 ppm and 100
ppm initial acarbose concentrations, respectively. This concludes that acarbose has been successfully
intercalated into the interlayers of montmorillonite and the intercalated amount increased with
increasing the initial acarbose concentration. Increased intensity and broadening of the peak
corresponding to vibrations of OH groups (3687–3125 cm-1) was observed in FTIR spectra of
acarbose intercalated montmorillonite, which may due to the presence of acarbose on or between the
layers of montmorillonite. The in-vitro drug releasing properties of acarbose from acarbose
intercalated montmorillonite was tested in artificial intestinal condition (pH 7.4 PBS solution) using
dialysis tube method. Acarbose releasing from the montmorillonite matrix was gradually increased in
the first 8 h and slow release was observed after that. Pseudo-second order kinetics model showed a
good fit (r2= 0.9767) for the acarbose releasing data suggesting the release of acarbose from MMT
matrix involves chemical desorption. Overall, this study demonstrates the potential applications of
montmorillonite as matrix material for sustained release drug formulations for future pharmaceutical
studies.
Keywords: Acarbose; Montmorillonite; Sustained drug releasing; XRD; FTIR
