ABSTRACTS OF PUBLISHED PAPERS
1.
R.S. OKOR, F.E. EICHIE AND C.N. NGWA (1998), "CORRELATION BETWEEN
TABLET
MECHANICAL
STRENGTH
AND
BRITTLE
FRACTURE
TENDENCY”. Pharm. Pharmacol. Commun., Vol. 4, pp. 511-513.
Abstract
High-compression loads often lead to lamination and capping (brittle fracture) during
tablet manufacture. Lactose granules containing 1, 2.5 or 5% w/w starch binder were
used to form tablets with and without a centre hole, at different compression loads. The
brittle fracture index (BFI) was estimated from the equation:
BFI = 0.5(T/T0 – 1)
where T0 and T are the tensile strength of tablets with and without a centre hole,
respectively. The effects of granule particle size on BFI and tensile strength were also
studied at a constant load. At a given binder level, an increase in compression load
increased tablet tensile strength, with a corresponding increase in BFI. Thus, BFI values
varied linearly with tensile strength (r > 0.98). The slopes of the BFI vs tensile strength
plots were 0.286 (1% binder), 0.181 (2.5% binder) and 0.098 (5% binder) indicating that
the effect of tensile strength on BFI was greater at lower binder levels. A decrease in the
particle size of the granules resulted in an increase in both tensile strength and BFI. In his
system BFI was also linearly related to tensile strength (r ≥ 0.95). The slopes of the BFI
vs tensile strength plots were 0.124 (1% binder), 0.096 (2.5% binder) and 0.092 (5%
binder). Again the effect of tensile strength on BFI increased at lower binder levels. BFI
is an inverse measure of plastic deformation during diametral compression. The results
show that hard tablets deform less readily which explains why high compression loads
lead to brittle fracture. Binder deficient formulations are also more susceptible to brittle
fracture.
1
2.
F.E. EICHIE and R.S. OKOR (1999), "ACRYLATE METHACRYLATE
COPOLYMER AS PRECOAT IN THE AQUEOUS POLYMERIC COATING
OF WATER LEACHABLE TABLETS”. Acta Poloniae Pharmaceutica Vol. 56,
No. 4, pp. 325-327.
Abstract
Organic film coatings of acrylate methacrylate (AMA), a water insoluble copolymer and
those of water soluble hydroxypropyl-methyl cellulose (HPMC) have been applied on
chloroquine tablets to determine their barrier property against aqueous penetration and
erosion of the tablet surfaces during pan coating. Barrier property of these film coatings
were measured by observing the time taken for a drop of water (0.05ml) to penetrate into
the coated tablet, whereas tablet erosion was indicated by the decrease in tablet thickness
after aqueous application on the coated tablets. Tablet disintegration times were
determined. The HPMC coatings showed minimum resistance generally to fluid
penetration and erosion of the films during aqueous application on the precoated tablets
whereas AMA coating offered high resistance to aqueous fluid penetration unto the tablet
cores. The barrier effect of the latter was further increased by increasing the content of
magnesium stearate in the coatings. Disintegration properties were not impaired,
attributable to the aqueous swellability and rupture of the AMA film. The cationic groups
in the AMA chemical structure imparted the swellability property. The indication is that
the acrylate methacrylate-magnesium stearate polymeric film coatings could effectively
serve as precoats in the aqueous polymeric coating of water leachaeable tablets.
3.
F.E. EICHIE, R.S. OKOR, and R. GRONING (2002), "APPLICATION OF
SOLUBILITY PARAMETERS TO THE FORMULATION OF ACRYLATE
METHACRYLATE FILM COATING SYSTEMS”. Journal of Applied Polymer
Science. Vol.87, 1339-1344.
Abstract
2
In order to optimize the formulation of the acrylate methacrylate (AMA) coating systems,
the partial solubility parameters of AMA and those of various coating solvents and
plasticizers have been computed using the group contribution method of Van Krevelan
and Hoftyzer. The data were analysed in accordance with the three-dimensional solubility
parameters whereby h (the hydrogen-bonding component) was plotted against the sum
of d (the dipole-dipole component) and p (the polar component). The data were also
analysed according to a two-dimensional solubility parameters whereby h was plotted vs
p to obtain the energy maps for the various compounds. With the three-dimensional
analysis, the position of the reference polymer in the energy map was centrally located
and was flanked by plasticizers and solvents that were shown experimentally to be
compatible with the polymer. On the other hand, the two-dimensional analysis displaced
the location of the reference polymer in the energy map leftward to the Y axis, and was
not flanked by plasticizers and solvents that were compatible with it. The results show
that the concept of the three-dimensional solubility parameters was more applicable to the
theoretical selection of plasticizers and solvents for the polymer studied.
4.
FLORENCE E. EICHIE and ROLAND S. OKOR (2002), "EFFECT OF ACID
TREATMENT ON THE CONSOLIDATION AND PLASTO-ELASTICITY OF
TAPIOCA POWDER”. Tropical Journal of Pharmaceutical Research. Vol.1(1),
45-49.
Abstract
Purpose: The effects of treating the tapioca (the fibrous residue obtained after up to 90%
of the proportion of starch has been removed from the peeled and rasped roots of cassava
tubers powder with dilute solutions of hydrochloric acid) in order to find an approach for
rendering an otherwise poorly compressible material to a directly compressible powder.
Method: The parameters measured were the degree of consolidation of the powder after
compression (i.e. the packing fraction of resulting tablets), the plasto-elasticity of the
powders as reflected by the brittle fracture index (BFI) of the tablets made from the
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powders and the viscosities of mucilages derived from the powders. The influence of
time of exposure and the concentration of acid used in the treatment were studied.
Results: The degree of consolidation of the powder increased slightly with increase in
duration of exposure to acid (24-72h) but drastically with increase in the acid
concentration from 0.1 to 0.4mol L-1. On the other hand, the plasto-elasticity of the
powders as measured by the BFI values and the viscosities of mucilages derived from the
powders decreased slightly with duration of exposure but drastically with increase in acid
concentration. A change in acid concentration was therefore the more determinant factor
with regards to the consolidation and plasto-elasticity properties of the powders. The
decrease in the viscosities of the mucilages following acid treatment of the powders was
indicative of a breakdown of polymeric structure in the powder.
Conclusion: Acid treatment of tapioca powder imparted plasticity in tapioca powder
which became compressible.
5.
FLORENCE E. EICHIE and ROLAND S. OKOR (2002), "PARAMETERS TO
BE CONSIDERED IN THE SIMULATION OF DRUG RELEASE FROM
ASPIRIN CRYSTALS AND THEIR MICROCAPSULES”. Tropical Journal of
Pharmaceutical Research. Vol.1(2), 99-110.
Abstract
Purpose: Drug microparticles may be microencapsulated with water-insoluble polymers
to obtain controlled release which may be further determined by the particle distribution.
The purpose of this study was to determine the drug release parameters needed for the
theoretical prediction of the release profiles of single aspirin crystals and their
microcapsules.
Method: Four single crystals of aspirin of varied weight and orthorthombic in shape or
their microcapsules also of varied weights were randomly selected for the study. The
microcapsules were walled with an acrylatemethacrylate copolymer (wall thickness,
11m). The following parameters were evaluated: the order of release, the dissolution
4
rate constant, k (crystals), the diffusion coefficient, D (microcapsules), the maximum
release M and time to attain it t. These parameters were in turn used to simulate the
release profiles of hypothetical single particles of a wide range size distribution, 0.31.4mm at 0.1mm intervals.
Results: The empirical single crystals exhibited an initial zero order (93%; dissolution
constant = 4.4min-1) followed by a first order release (6%; dissolution constant = 0.38
min-1). Maximum release from each of the crystals was 99% of the initial particle weight;
thus m was a constant fraction of the initial particle weight. A zero order release
consistent with a Fickian diffusion model was displayed by the single microcapsules
(diffusion coefficient, 5.4 x 10-4mm2min-1). At same particle weight the release
parameters m, t and the slopes of the rate order plots compared favourably with the
theoretical data.
Conclusion: The study indicates that the empirical release data on a few single particles
can be used to predict the release profiles of single particles of a wide range of size
distribution. This finding may be exploited in the prediction of drug release from
polydisperse systems.
6.
FLORENCE E. EICHIE and ROLAND S. OKOR (2003), "MODELLING OF
DRUG RELEASE FROM ENSEMBLES OF ASPIRIN MICROCAPSULES OF
CERTAIN
PARTICLE
SIZE
DISTRIBUTION”.
Tropical
Journal
of
Pharmaceutical Research. Vol.2(1), 137-145.
Abstract
Purpose: In order to determine the drug release profile of an ensemble of aspirin crystals
or microcapsules from its particle distribution a mathematical model that considered the
individual release characteristics of the component single particles was developed. The
model assumed that under sink conditions the release from individual (component)
particles would be independent of each other and hence simply additive.
5
Method: The release parameters, mt = the amount of drug released in time t, m = the
maximum release and t = the time to attain it were determined for each single particle by
simulation using previously derived mathematical models. To obtain the cumulative
release curve for the ensemble the individual releases were summed up at each time scale
and for the various time intervals. Values of M and t for the ensemble were obtained
from the simulated cumulative curves. The release profiles of the ensembles were also
determined experimentally and their m and t values deduced from the release curves.
Results: The observed cumulative curves of the ensembles compared favourably with the
simulated data. The % difference in the observed and the simulated m and t values of
the ensembles was within  20%, which indicated that the modelling was valid.
Conclusion: The study showed that the release profile of an ensemble can be determined
from its particle distribution which has application in controlled release studies.
7.
M.U. UHUMWANGHO, R.S. OKOR and F.E. EICHIE (2004), "EFFECT OF
CATION
CONTENT
OF
CERTAIN
AMMONIOMETHACRYLATE
COPOLYMERS TYPE A (RL) AND B (RS) ON THEIR BINDER PROPERTY
IN TABLETING”. Acta Polonae Pharmaceutica - Drug Research. Vol.61 (4), 255258.
Abstract
Tablets of salieylic acid (drug model) have been formed using two analogous
acrylatemethacrylate copolymers designated here as A and B as binders. A and B differ
only in their content of quaternary ammonium (cationic) groups in the ratio 2:1 (A:B).
The aim was to investigate the effect of the cationic groups on the tableting
characteristics of the formed granules. In the procedure, aqueous dispersions of the
polymers of concentration 1 to 5% w/w were used in a separate experiment for
granulation of the salicyclic acid powder and then labeled. The final concentration of the
binder in the tablets varied from 0.4 to 2% w/w. The parameters assessed were the tablet
tensile strength (T) and their brittle fracture index (BFI) which are indicative of the plasto
6
elasticity of the granules: for instance, a high T value together with a low BFI value are
indicative of a high plasto elasticity. A and B generally displayed a strong binder
property as they individually produced hard tablets even at the low concentration 0.4%
w/w. As the binder concentration in the tablets increased to 2% w/w, tensile strength
(MNm2) increased from 1.08 to 1.80 (tablets of polymer A), 1.08 to 2.02 (tablets of
polymer B). BFI values decreased from 0.24 to 0.06 (tablets of polymer A) and 0.16 to
0.04 (tablets of polymer B). These results indicate that the presence of the cationic groups
in the polymer structure promoted elastic rather than plastic compression.
8.
ROLAND OKOR, OLANIKE FAJUYIGBE AND FLORENCE EICHIE*,
(2004). "AMPICILLIN ADSORPTION BY SOME ANTACIDS”. Scientia
Pharmaceutica (Sci. Pharm). Vol. 72, 309-316.
Abstract
In certain situations of peptic ulcers ampicillin has been co-administered with bismuth
carbonate with an implication for adsorption of the ampicillin. To quantify this effect the
kinetics and extent of adsorption of the ampicillin by some commonly used antacids were
measured; these are bismuth carbonate, magnesium tricilicate and aluminium hydroxide.
The adsorption of ampicillin by bismuth carbonate followed the Langmuir absorption
isotherm, which suggests chemisorptions. It was characterized by a strong adsorption at a
low absorbate (ampicillin) concentration but the % adsorption decreased with increase in
adsorbate concentration, which is a feature of a saturated monolayer adsorption. On the
other hand, the adsorption by magnesium trisilicate and aluminium hydroxide followed
the Freundlich adsorption isotherm characterized by a low adsorption at a low adsorbate
concentration but this increased slightly with increase in adsorbate concentration,
suggesting a weak physical adsorption. The adsorption capacities (mg/g) of the adsorbate
were 1.64 (bismuth carbonate) 0.04 (magnesium carbonate) and 0.03 (aluminium
hydroxide). Bismuth carbonate thus gave by far the highest degree of adsorption. The
conclusion is that the co-administration of ampicillin and bismuth carbonate in the
treatment of certain peptic ulcers is erroneous.
7
9.
FLORENCE EICHIE*, ROLAND SYDNEY OKOR and RUDIGER GRONING
(2005), "LIMITATION OBSERVED IN THE APPLICATION OF THE THREE
DIMENSIONAL
SOLUBILITY
FORMULATION
OF
PARAMETERS
POLY
TO
THE
COATING
(3-HYDROXYBUTYRATE-
HYDROXYVALERATE) SYSTEMS”. Tropical Journal of Pharmaceutical
Research. Vol.4(1), 355-362.
Abstract
Purpose: Poly (3-hydroxybutyrate-hydroxyvalerate) displayed high dipole-dipole
interaction, a high hydrogen bonding but low polar interaction and was therefore
expected to be miscible with solvents/plasticizers that exhibit similar pattern of cohesive
interaction. To determine the applicability, or otherwise of the theory of the three
dimensional solubility parameters to the formulation of poly (3-hydroxybutratehydroxyvalerate) polymeric coating system, and hence identify any limitation in the
application of the theory. This aspect was investigated in the study.
Method: The structural group contribution method was employed to compute the partial
and total solubility parameters of the compounds – the biopol polymer, a series of organic
solvents and plasticizers. The computed partial solubility parameters included: dipoledipole (d), polar (p) and hydrogen bonding (p). Following a standard procedure in the
literatures, the d and p values were combined to form a composite solubility parameter,
v: where v =√𝛿𝑑2 + 𝛿𝑝2 . A plot of h versus v gave the energy maps, which depicted the
energy levels of the various compounds and from which the miscibility of the compounds
were predicted. The closer the position of the solvent or plasticizer to the polymer in the
map, the greater, the probability of mixing. Cast films of the various polymeric
formulations were made and examined for homogeneity by scanning electron
microscopy.
Results: It was possible to select suitable plasticizers that were miscible with the polymer
by applying theory of solubility parameters. The prediction for the solvents was,
however, erroneous and this may be attributable to the inability of the v parameter to
8
clearly reflect the differences between the d and p interactions of the polymer on the
one hand and those of the various solvents in all situations on the other hand. This means
that in certain instances, the v values of the polymer and the solvents were similar even
though their d and p interactions were dissimilar.
Conclusion: The analysis of the data showed that the composite solubility parameter v
of compounds could be similar even though the actual energies of d and p interactions
are different. This is a limitation in the application of the theory of the three dimensional
solubility parameters.
10.
FE EICHIE*, RS OKOR, MU UHUMWANGHO and IY OSAKUE (2005),
"RELATIONSHIP BETWEEN SLUGGING PRESSURE AND BRITTLE
FRACTURE TENDENCY – A CASE STUDY FOR ASPIRIN TABLETS”.
Tropical Journal of Pharmaceutical Research. Vol.4(2), 483-487.
Abstract
Objective: Slugging is a pre-compression technique for the dry granulation of
hydrolysable drugs (e.g. aspirin). The study was carried out to relate the slugging load to
the hardness of the granules and the brittle fracture tendency of the final (recompressed)
tablets.
Method: Varying compression load were applied to aspirin powder to form slugs, which
were subsequently broken down to form granules. These were recompressed to give the
final tablets. The hardness of the slugs was determined and taken as measure of the
hardness of the resulting granules. The following tableting parameters were measured for
the final tablets – tensile strength (T), packing fraction (Pt) and the brittle fracture index
(BFI).
Results: A high slugging load was associated with the formation of hard slugs and hence
hard granules. Upon recompression the hardest granules formed the hardest tablets (T =
3/29MN m-2) while the softest granules formed the softest tablets (T = 1.09MNm-2). In
turn, the hardest tablets displayed the highest brittle fracture tendency (BFI = 0.59)
9
compared with the softest tablets (BFI = 0.21). A positive linear correlation existed
between tablet hardness (T) and BFI values (r=0.98).
Conclusion: The study showed that excessive slugging load produces hard aspirin
granules which in turn yields hard but friable tablets.
11.
IFEYINWA F. OBUEKWE* AND FLORENCE EICHIE (2006), “THE
PRESENCE OF MICROORGANISMS IN SOME COMMON EXCIPIENTS
USED IN TABLET FORMULATION”. Acta Poloniae Pharmaceutica – Drug
Research. Vol .63 N0. 2: 121-125.
Abstract
Strict measure on the need to control microbial contamination in the formulation of solid
dosage forms such as tablets and capsules are not usually in place as is done in other
pharmaceutical preparations. The presence of microorganisms in some common
excipients such as starch and lactose powders, and distilled water used in tablet
formulation was investigated in this study. Organisms isolated were Geotrichuim and
Aspergillus spp as well as two strains of Staphylococcus aureus. Lactose tablets were
further formulated using 5% starch as binder. Some of the isolated organisms were, in
turn, inoculated into these tablets and stored over a period of several weeks. The physical
properties of these tablets were determined at various time intervals. Marked increases in
the disintegration times of these tablets were observed, while there was a decrease in the
hardness property for both the fungi and bacteria. These observed effects have serious
implications in the overall bioavailability of drugs such as tablets formulated from
contaminated excipients.
10
12
F.E.
EICHIE*,
R.S.
OKOR
and
R.
GRONING
(2006),
“SOLUTE
PERMEABILITY OF CERTAIN POLYMERIC FILMS APPLIED ON ASPIRIN
CRYSTALS TO FORM MICROCAPSULES”. Journal of Macromolecular
Science. Vol. 45, 801-810.
Abstract
A study was carried out to investigate the solute permeability of various polymer films
applied on aspirin crystal to form microcapsules. The coating materials were an acrylate
methacrylate (AMA), poly 3-hydroxybutyrate-hydroxycakerate (Biopol) and poly (lacticglycolic) acid (PLGA). Organic solutions of the polymers were applied on the aspirin
crystals (core) by a spray coating technique in a Wurster column. The microcapsule
surfaces were investigated using scanning electron microscopy (SEM), while
permeability studies were carried out on single microcapsules serving as micro dialysis
cells. The amount of drug (m) permeating through the applied firms in time (t) was
analysed on the basis of Fickian diffusion. The SEM revealed numerous surface pores of
size range 2.4 to 24µm for the AMA films, while the PLGA and Biopol films, on the
other hand, exhibited very few surface pores of size range 2.2 to 18µm. However, the
AMA films were more spongy than the PLGA and Biopol. The AMA films displayed a
retarded release while the PLGA or Biopol films displayed a burst release, attributable to
the differences in the film’s porous structure. The Permeability coefficient (P) depended
on the core weight of the single microcapsules, decreasing with increase in core weight.
Thus, for an ensemble of the microcapsules the permeability coefficients of the films of
the component microcapsules will have a distribution of P values even though the coating
material is the same. This finding is important in the simulation of drug release from
coated multiparticulate systems.
13.
UHUNWANGHO, M.U., OKOR, R.S., EICHIE, F.E. AND ABBAH, C.M.
(2006), “INFLUENCE OF SOME STARCH BINDERS ON THE BRITTLE
FRACTURE TENDENCY OF PARACETAMOL TABLETS”. African Journal of
Biotechnology. Vol.5 (20), 1950-1953.
11
Abstract
The study was carried out to compare the binder effects of cassava and cocoyam starch
with that of maize starch BP. The parameters investigated were the brittle fracture index
(BFI), the tablet packing fraction (Pt) and tensile strength (T). Mucilages of the starches
of varying concentrations; 15, 20, and 25% (w/v) were formed; their viscosities were
determined and used to form paracetamol granules by wet-massing. The granules were
compressed at different compression loads (arbitrary units on the load scale; 8, 9 and
9.5). At all given compression loads and at all binder concentration, cassava starch
muculages binder produced the hardest and most compact tablets with the least tendency
to brittle fracture compared with cocoyam or maize starch mucilage. For instance, the
BFI values at the compression load, 8 were 0.13 (tablets formed with cassava starch
mucilage 20% w/v) 0.18 (tablets formed with cocoyam starch mucilage 20% w/v) and
0.35 (tablets formed with maize starch mucilage 20% w/v). Increase in compression load
(8 to 9.5) increased the BFI of these tablets while an increase in binder concentration
generally caused a decrease in BFI of these tablets. This decrease was less marked at
higher compression load. The results indicate that cassava starch mucilage which was the
most viscous, displayed the highest potential for ameliorating brittle fracture during
manufacture of paracetamol tablets.
14.
R.S. OKOR, F.E. EICHIE, M.U. UHUMWANGHO and A.P. AKA-AHA (2007),
“EFFECT OF PROTECTIVE COATING OF ASPIRIN TABLETS WITH
ACRYLATEMETHACRYLATE
COPOLYMERS
ON
TABLET
DISINTEGRATION TIMES AND DISSOLUTION RATES”. Indian J. Pharm.
Sci. Vol .69 (4), 589-591.
Abstract
Tablets of aspirin (a moisture degradable drug) have been film coated with two analogous
Eudragit RL and RS copolymers designated here as A and B which differ only in their
cation content in the ratio 2:1 (A:B). A, is therefore more hydrophilic than B. The tables
were film coated with ethanol solutions of these two polymers. Film coating with either
12
A or B significantly reduced the moisture uptake potentials of the tablets but caused an
increase in the disintegration times of the tablets and retarded dissolution rates. The mean
disintegration times were 0.5±3.6min (tablets coated with B). The corresponding
dissolution rates % h-1 were 28.3 for uncoated, 16.6, coated with A and 14.8 coated with
B, respectively. Thus, coating with polymer B considerably impaired the disintegration
and dissolution properties of the tablets.
15.
EICHIE, F.E. and AMALIME, A.E. (2007), “EVALUATION OF THE BINDER
EFFECTS OF THE GUM MUCILAGES OF Cissus Populnea AND Acassia
senegal ON THE MECHANICAL PROPERTIES OF PARACETAMOL
TABLETS”. African Journal of Biotechnology. Vol.6(19), 2208-2211.
Abstract
A comparative study has been carried out to investigate the binder effects of the gums of
Cissus populnea and Accasia Senegal on the mechanical properties of paracetamol
tablets. Tablet mechanical properties evaluated include the packing fraction (Pt), the
tensile strength (T) and the brittle fracture tendency (BFI). Varying concentrations of the
gum mucilage ranging from 1-15% (w/v) was prepared and their relative viscosities
determined. Each concentration was used to wet massed paracetamol powder to form
granules. Tablets of paracetamol (500±6.5mg) were compressed at a constant
compression load (7 arbitrary units on the scale). The tablets were equilibrated for 24h
before evaluation. At all binder concentrations A. senegal gum produced harder and more
consolidated tablets than C. populnea as reflected by the higher T and Pt values
respectively. For instance, the T and Pt values of the tablets at binder concentration of
10% (w/v) were 0.69 MNm-2 and 0.47 (A. senegal) and 0.57MNm-2 and 0.23 (C.
populnea), respectively. On the contrary, an increase in binder concentration generally
resulted in a decrease in BFI values and this decrease was more marked with C.
populnea. The study showed that A. senegal mucilage displayed better tableting
characteristics and higher tendency for ameliorating capping tendency. Both mucilages
13
have the potentials for substitution as binder for the more expensive starches in tablet
formulation.
16.
EICHIE FE and OKOR RS (2006), “APPLICATION OF A CERTAIN
ACRYLATEMETHACRYLATE (WATER-INSOLUBLE) COPOLYMER IN
PROTECTIVE COATING OF ASPIRIN TABLETS”. Journal of Pharmaceutical
Research. Vol.6(1), 17-19.
Abstract
Water-insoluble polymers such a acrylatemethacrylate (AMA) copolymer used in this
study ordinarily are not suitable materials for the protective coating of moisture sensitive
drugs (e.g. aspirin), because of the requirements for the rapid disintegration and
dissolution of such coated tablets. The objective of this study, therefore, was to
investigate the effect of inclusion of hydrophilic filters in the film composition of an
acrylatemethacrylate (AMA) copolymer applied in the protective coating of aspirin
tablets. The parameters evaluated were the disintegration and dissolution profiles and the
dissolution rate constraints. The hypothesis was that the dispersion of the hydrophilic
filters in the film coat would weaken polymer – polymer cohesion and also the swelling
or leaching of the additive would increase the porosity of the film when the coated tablet
is placed in the aqueous disintegration/dissolution medium. An organic solution of AMA
10% w/v in acetone (film thickness 5 ± 1.0µm) was first applied on the tablets, followed
by an aqueous film coating using a laboratory coating pan (Manesty Machines Ltd UK,
model 15096-8) maintained at 600C atmospheric pressure. The final coating thickness
was 45±4.2µm. The role of the organic precoat was to serve as a barrier to prevent water
access to the core. The disintegration time of the tablets coated with the polymer only
was 8.5in, while the corresponding values for tablets coated with a mixture of the
polymer 25% and the filler, starch or citric acid, 75% were 1.5 min (starch filler) and
5min (citric acid filler). The dissolution rates of tablets coated with the polymer only was
0.21mg min-1 while the corresponding values for tablets coated with a mixture of the
polymer 25% and the filler, 75% were 0.73mg min-1 (starch as filler) and 0.64mg min-1
14
(citric and as filler). The presence of the fillers in the film composition thus decreased the
disintegration times but increased the dissolution rates of the coated tablets. These effects
were attributed to the swelling of starch to cause film rupture and the leaching of the
citric acid to increase the porosity and hence the water uptake capacity of the films. The
study has shown that in certain circumstances the copolymer can in fact be used as a
protective coating material without sacrifice to the disintegration and dissolution
properties of the tablets.
17.
FLORENCE E. EICHIE*, ROLAND S. and OKOR OMAMERI ESI (2008),
“MATRIX RELEASE FROM TABLETS PREPARED WITH AQUEOUS
DISPERSION
OF
AN
ACRYLATE
METHACRYLATE
(A
WATER-
INSOLUBLE) COPOLYMER AS BINDER”. International Journal of Health
Research. Vol.1(4), 235-240.
Abstract
Purpose: To investigate the binder effect of aqueous dispersions of acrylate
methacrylates (AMA) copolymer with a view to obtaining matrix (non-disintegrating)
tablets with a retard release property.
Methods: Aqueous dispersions of AMA (1-15% w/v) were formed by a coacervation
procedure using ethanol (10ml) as solvent and water (90ml) as non-solvent for the
copolymer. The aqueous dispersions were used to wet-mass the drug (paracetamol)
powder. Resulting granules were compressed to 500 mg tablets using a single punch
machine. The tablets were subjected to hardness, friability, disintegration and dissolution
tests.
Results: The granules formed hard tablets (tensile strength 1-2.0 MNm-2) with low
friability decreasing from 2 to 1 % as the AMA binder concentration increased from 0.75
to 11.25% w/w. The tablets failed to disintegrate in 3hr. Drug release generally followed
the Higuchi square root of time kinetic (R2 > 0.95). The AMA binder markedly retarded
15
drug release as reflected by the sharp decrease in the dissolution rate constant from 30
min-2 (AMA, 0.75% w/w) to 9 min-2 (AMA, 11.25% w/w).
Conclusion: The AMA dispersion is an effective binder, producing matrix tablets with a
retard release property controlled by the binder content in the tablets.
18.
EICHIE FE, OKOR RS and UHUMWANGHO MU (2008), “PRELIMINARY
REPORT ON THE MODIFIED COMPRESSION PROPERTIES OF TAPIOCA
POWDER: PART 2”. Journal of Pharmaceutical Research. Vol.7(1), 24-26.
Abstract
Tapioca is a cellulosic material obtained as a by-product during starch extraction from
cassava (i.e. Manuihut utilissima) tubers. It has a potential as a tablet base; but it is poorly
compressible due to its elasticity. Hence, in order to render it plastic and compressible it
was treated with a dilute acid, HCL (0.1mol. L-1) for 24h at 500C. The hypothesis was
that the acid would break down the branched cellulosic polymers, which is elastic to less
elastic linear polymers. The parameters investigated were the consolidation property of
the powder as measured by its packing fraction (Pt) and its tableting characteristics as
measured by its tensile strength (T) and brittle fracture index (BFI). The packing fraction
of the untreated powder was 0.31 and that of the acid treated powder was 0.40; this
difference was slight but statistically significant. With regard to compressibility of the
powder the untreated sample formed crumbly tablets of no measurable tensile strength;
while the acid treated sample gave hard tablets of tensile strength 0.36 MNm-2 but a low
brittle fracture index of 0.33. The results suggest that the acid treatment conferred
plasticity on the powder and rendered it directly compressible without granulation.
19.
FLORENCE E. EICHIE, IKHUORIA M. ARHEWOH and OLIVER C. EZEOBI
(2009), “IN-VITRO EVALUATION OF THE PHARMACEUTICAL QUALITY
OF SOME IBUPROFEN TABLETS DISPENSED IN NIGERIA”. African
Journal of Pharmacy and Pharmacology. Vol.3(10), 491-495.
16
Abstract
The purpose of this study was to determine the pharmaceutical quality of some Ibuprofen
tablets dispensed in Nigerian. 19 different brands of Ibuprofen tablets were purchased
form pharmacles and open markets in 3 states in Nigeria. The organoleptic and
physicochemical properties of these Ibuprofen tablets were assessed according to British
Pharmacopoela (BP), and unofficial standards as recommended by the manufacturers. Of
the 19 brands of tables assessed, 12 brands passed the uniformity of content test while 15
brands passed the disintegration test and only four brands passed the dissolution test.
Ibuprofen tablets dispensed in Nigeria varied considerably in their pharmaceutical
quality. A strict check of the quality of brands of Ibuprofen by regulatory agencies and
distributors before they are dispensed to the public is therefore recommended.
20.
FLORENCE E. EICHIE, JUDE E. ISESELE and MARY-ANN O ABHULIMEN
(2010), “EVALUATION OF THE RELEASE OF PROFILES OF IBUPROFEN
FORMULATED FROM CARNUBA WAX AND HOMOLIPID CAPRA
HIRCUS”. International Journal of Health Research. Vol.3 (4), 229-233.
Abstract
Purpose: To investigate the sustained release characteristics of ibuprofen lipospheres
made from Capra hircus (GF) and carnauba wax (CW) in comparison with conventional
granules as standard.
Methods: Ibuprofen (90 g) and the lipid (30 g) were prepared by melt dispersion
technique. Conventional granules of ibuprofen were prepared with starch mucilage, 20%
w/v. Resulting lipospheres were characterized with respect to sizes, flow property, bulk
and tap densities, encapsulated in hard gelatin capsules and evaluated for drug release
profiles.
Results: Dissolution profile for lipospheres were a maximum drug release of 97% in 1hr
(conventional granules), 23% in 4hr (GF), 60% in 2hr (CW) and 40% in admixtures of
fats (GC), Admixing the fats enhanced the release profiles from the lipospheres.
17
Conclusion: Formulation of ibuprofen into lipospheres modified the release profile,
which has implications in the formulation of sustained release multiunit dosage forms.
18