EVALUATION OF MODIFIED STARCHES AND MUCILAGE DISPERSIONS OBTAINED FROM IPOMOEA BATATAS L. LAM (CONVOLVULACEAE) AS BULK EXCIPIENTS IN CHEWABLE TABLET FORMULATIONS
EVALUATION OF MODIFIED STARCHES AND MUCILAGE DISPERSIONS OBTAINED FROM IPOMOEA BATATAS L. LAM (CONVOLVULACEAE) AS BULK EXCIPIENTS IN CHEWABLE TABLET FORMULATIONS
No Thumbnail Available
Date
2014-05
Authors
ACHOR, Mohammed
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Increasing attention has been paid to incorporating hydrocolloids into starch-based products
due to their unique functional properties and bio-safety. The aim of this work was to
determine the suitability of modified starch and mucilage dispersions obtained from Ipomoea
batatas as direct compression excipients in chewable tablet. Native starch (SPS) and
mucilage were extracted from Ipomoea batatas. Subsequently, SPS was pregelatinized (PPS)
and acid modified (APS) and dispersions of mucilage with SPS, PPS and APS in a ratio 1:20,
1:10, 2:10, 3:10 and 4:10 respectively were produced. The dispersions were characterized
using standard methods for their particle size, flow properties, moisture sorption capacity,
true density, porosity, hydration and swelling capacity. Pasting and thermal properties,
syneresis, dilution capacity, lubricant sensitivity, compaction studies using the Heckel and
Kawakita parameters, panel assessment of formulated chewable tablets and accelerated
stability studies was also carried out. Generally, an increase in particle size, flow properties,
moisture sorption capacity, true densities and a decrease in porosity, hydration and swelling
capacity were observed as the mucilage concentration increased. Dispersions of SPS, PPS
and APS in mucilage showed an increase in peak time, pasting temperature and enthalpy
change as the mucilage concentration increased and a decrease in peak viscosity, syneresis
(except SPS), peak temperature (except APS) as the mucilage concentration increases.
Dispersions in mucilage generally led to an increase in disintegration time, crushing and
tensile strength with a decrease in friability of formulated compacts (placebo). Optimized
dispersions of mucilage in SPS, PPS and APS in a ratio 3:10 (i.e. 30-MSPS, 30-MPPS and
30-MAPS respectively) were used for further studies. The order of mean yield pressure (Py)
for native and modified starches were APS > PPS > SPS and for their dispersions, 30-MSPS
> 30-MPPS > 30-MAPS while Pk was in the order SPS > PPS > APS. In other words,
modification of starch increases the plastic deformation of the native starch but reduces the
plastic deformation of their dispersions in the order: 30-MAPS > 30-MPPS > 30-MSPS. The
elastic recovery and brittle fracture index were in the order SPS > APS > PPS, while for their
dispersions, which showed a decrease in elastic recovery and brittle fracture index as
compared to their parent forms, were in the order; 30-MAPS > 30-MPPS > 30-MSPS. The
order of dilution capacity index was MCC > 30-MPPS > 30-MAPS > 30-MSPS > mannitol.
The overall order of lubricant sensitivity ratios at lower pressure was MCC < mannitol < 30-
MPPS < 30-MAPS < 30-MSPS and at higher pressures, 30-MAPS < 30-MPPS < 30-MSPS <
MCC < mannitol. All ascorbic acid chewable tablets made from starch dispersions were
round and brown in colour without any tablet defects and had a characteristic sweet potato
flavour. Generally, formulations F1 – F6 which contained starch dispersion alone had
acceptable friability (< 1 %), crushing strength (> 3 Kgf) and disintegration time (< 15 min).
Increase in concentrations of binary mixtures of mannitol and maltitol gave tablets with
unacceptable properties. Tablets with acceptable friability, crushing strength and
disintegration time were used to determine the degree of acceptance of the formulated
ascorbic acid chewable tablets. Formulation F6 had the highest degree of acceptance while
formulation F20 had the lowest. Formulations F4 – F6, which had higher degree of
acceptance, were subjected to acceleration stability studies at 40 0C/75 % relative humidity
for 3 months. There was a gradual decrease in disintegration time and crushing strength
within the duration of study for all formulations. There was no significant difference (p <
0.05) within the cummulative drug release of optimized formulations. Modified starch and
mucilage dispersion possessed excellent properties as excipient for ascorbic acid chewable
tablet formulations using the direct compression method in view of its physicochemical and
material properties as well as its positive panel assessment and stability over time.
Description
A DISSERTATION SUBMITTED TO THE SCHOOL OF POSTGRADUATE
STUDIES, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA IN PARTIAL
FULFILMENT FOR THE AWARD OF DOCTOR OF PHILOSOPHY IN
PHARMACEUTICS
DEPARTMENT OF PHARMACEUTICS AND PHARMACEUTICAL
MICROBIOLOGY, FACULTY OF PHARMACEUTICAL SCIENCES,
AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
MAY, 2014
Keywords
EVALUATION,, MODIFIED,, STARCHES,, MUCILAGE,, DISPERSIONS, OBTAINED,, IPOMOEA,, BATATAS,, ONVOLVULACEAE,, BULK,, EXCIPIENTS,, CHEWABLE,, FORMULATIONS