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Research Article
Grewia Gum 1: Some
Mechanical and Swelling Properties of Compact and Film
Elijah I Nep1,2* and Barbara R Conway1,3
Life
and Health Sciences, Aston University, Aston Triangle,
Birmingham B4 7ET, United Kingdom, 2Department
of Pharmaceutics and Pharm. Technology, University of
Jos, Nigeria, 3Pharmacy, School of Applied
Sciences, University of Huddersfield, Huddersfield HD1
3DH, United Kingdom
For correspondence:
E-mail:
nepeli2000@yahoo.com Tel:
+234-8166116714
Received: 30 October 2010
Revised
accepted: 8 June 2011
Tropical
Journal of Pharmaceutical Research, Aug 2011;
10(4): 385-392
http://dx.doi.org/10.4314/tjpr.v10i4.3
Abstract
Purpose:
To study the
mechanical and dynamic swelling properties of grewia
gum, evaluate its compression behaviour and determine
the effect of drying methods on its properties.
Methods:
Compacts (500 mg) of both freeze-dried and air-dried
grewia gum were separately prepared by compression on a
potassium bromide (KBr) press at different pressures and
subjected to Heckel analysis. Swelling studies were
performed using 200 mg compacts of the gum (freeze-dried
or air-dried) compressed on a KBr press. The mechanical
properties of the films of the gum prepared by casting 1
% dispersions of the gum were evaluated using Hounsfield
tensiometer. The mechanical properties of grewia gum
films were compared with films of pullulan and guar gum
which were similarly prepared. The effect of temperature
on the water uptake of the compacts was studied and the
data subjected to Schott’s analysis.
Results:
Drying conditions
had no effect on the yield pressure of the gum compacts
as both air-dried and freeze-dried fractions had a yield
pressure of 322.6 MPa. The plots based on Schott’s
equation for the grewia gum samples showed that both
samples (freeze-dried and air-dried) exhibited long
swelling times. Grewia gum film had a tensile strength
of 19.22±3.61 MPa which was similar to that of pullulan
films (p > 0.05). It had an elastic modulus of 2.13±0.12
N/mm2 which was significantly lower (p <
0.05) than those of pullulan and guar gum with elastic
moduli of 3.33±0.00 and 2.86±0.00 N/mm2,
respectively.
Conclusion:
The type of drying method used does not
have any effect on the degree of plasticity of grewia
gum compacts. Grewia gum obtained by either drying
method exhibited extended swelling duration. Matrix
tablet formulations of the gum will likely swell slowly
and promote sustained release of drug.
Keywords:
Grewia gum
compact, Films, Heckel analysis, Swelling behaviour |
