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The effect of pharmaceutical excipients on isoniazid release from chitosan beads / Deon van RensburgVan Rensburg, Andries Gideon January 2007 (has links)
In controlled release applications a drug is molecularly dispersed in a polymer phase. In
the presence of a thermodynamically compatible solvent, swelling occurs and the
polymer releases its content to the surrounding medium. The rate of the drug release can
be controlled by interfering with the swelling rate of the beads or by influencing diffusion
through the viscosity of the polymer.
Beads that contain chitosan were prepared through the ionotropic gelation method where
tripolyphosphate (TPP) was used as the crosslinking agent. Beads that consisted of 3%
w/v isoniazid (lNH) and 5% w/v chitosan were prepared in a 5% w/v TPP solution (pH
8.7) as the primary beads. To improve the drug loading of chitosan isoniazid beads (ClB)
the TPP concentration, pH of the TPP solution and the INH concentrations were altered
for maximum drug loading. To increase the porosity of the beads of chitosan beads
Explotab® (EXPL), Ac-Di-Sol® (ADS) and Vitamin C (VC) were added individually to
chitosan solutions at concentrations of 0.1, 0.25 and 0.5% w/v before adding the mixture
to the TPP solution. Morphology, swelling and drug loading studies were used to
evaluate the different formulations. After these excipients were added individually they
were also added in combinations of two excipients respectively and characterised. From
the results of the drug loading studies the beads that contained only chitosan and
isoniazid showed a percentage drug loading of (43.92%) which is the best of all the beads
that were analyzed. The multi excipient combination of Ac-Di-Sol® and Explotab®
showed the best swelling capability at both pH levels.
Dissolution studies were conducted on all the formu lations over a period of 6 hours (360
minutes) at pH 5.6 and pH 7.4. From the dissolution results it were clear that no chitosan
dissolved at both pH values. The dissolution of single pharmaceutical excipient (SPE)
and multi pharmaceutical excipient (MPE) formulations can be arranged in the following
order: VC/ADS < VC < ADS/EXPL < ADS < VC/EXPL < CIB < EXPL. Explotab® is a
potential excipient for enhanced drug release over a wide pH range. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
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The effect of pharmaceutical excipients on the release of indomethacin from chitosan beads / Riana HavingaHavinga, Riana January 2006 (has links)
Contents: Chitosan -- Controlled drug delivery -- Indomethacin -- Inotropic gelation -- Tripolyphosphate (TPP) -- Explotab® -- Ac-Di-Sol® -- Vitamin C / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
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The effect of pharmaceutical excipients on the release of indomethacin from chitosan beads / Riana HavingaHavinga, Riana January 2006 (has links)
Chitosan has proven through the years as a versatile biomaterial to be used in pharmaceutical applications. Its mucoadhesive properties as well as its ability to manipulate the tight junctions in epithelium membranes have qualified it as an effective drug carrier in controlled drug delivery systems. Microparticles or beads as they are forward called in this study have advantages over conventional drug dosage forms because of a large surface to volume ratio and have the ability to target a specific site for drug release. Indomethacin is an anti-inflammatory drug that causes gastrointestinal side effects in conventional immediate-release dosage forms.
The goal is to manipulate the drug delivery vehicle to target the intestines/colon as the site for drug delivery and to minimize this side effect. Thus chitosan beads have been chosen as a drug delivery system for indomethacin in this study.
Chitosan beads have been prepared through the ionotropic gelation method using tripolyphophate (TPP) as a cross-linking agent. To prepare the most effective bead to encapsulate indomethacin different formulation and system variables (pH of the TPP solution, the concentration of the TPP solution as well as the indomethacin concentration) have been evaluated according to the following parameters: morphology, drug loading capacity and swelling capability. The ideal pH of the TPP solution was determined at 8.7 and the most effective TPP and indomethacin concentration were 5% w/v and 4% w/v respectively. The chitosan concentration was kept at 3% w/v throughout the study. These concentrations were used to examine the effect of pharmaceutical excipients on the indomethacin release from chitosan beads.
The effect of the different excipients namely, ExplotabⒽ(0.25% w/v), Ac-Di-SolⓀ (0.5% w/v) and Vitamin C (0.25% w/v), on the morphology, drug loading capacity, swelling capability as well as the drug release of indomethacin chitosan beads (ICB's) were also studied. The excipients were used in the individually above mentioned concentrations and in combination with each other in the same concentrations. These formulations were used in dissolution studies over a period of 6 hours in PBS pH 7.4 solutions. The indomethacin release rate increased when an excipient was added to the formulation and it dramatically increased when the excipients were added in their various combinations, compared to the formulation that did not contain excipients. / Contents: Chitosan -- Controlled drug delivery -- Indomethacin -- Inotropic gelation -- Tripolyphosphate (TPP) -- Explotab® -- Ac-Di-Sol® -- Vitamin C / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
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The effect of pharmaceutical excipients on rifampicin release from chitosan beads / Mangaabane Gorden MohlalaMohlala, Mangaabane Gorden January 2004 (has links)
Controlled release systems aim at achieving a predictable and reproducible drug
release over a desired time period. These systems allow reduced dosing frequency,
constant drug levels in the blood, increased patient compliance and decreased adverse
effects. In a recent study, Chitosan beads, containing N-trimethyl Chitosan chloride,
have shown a potential in the delivery of rifampicin. However, because of inadequate
amounts of rifampicin released over 24 hours, incorporation of other pharmaceutical
excipients to increase the swelling behaviour of the beads to improve drug release,
was considered in this study.
Chitosan beads were prepared through ionotropic gelation with tripolyphosphate
(TPP) as a crosslinking agent. To increase the porosity if the Chitosan beads
Explotab®, Ac-Di-Sol® and vitamin C were added individually to Chitosan solutions
at concentrations of 0.1, 0.25 and 0.5 % w/v before adding the mixture to the TPP
solution. Swelling and morphology studies were used in the evaluation of the different
formulations. The swelling and morphology results were then used to select a set of
combination and concentrations of two excipients sand then prepare and characterise
beads containing two combinations. The combination formulations and formulations
containing single excipients were then loaded with rifampicin. Pure chitosan beads
exhibited a higher drug loading capacity (67.49 %) compared to the lowest loading
capacity of 41.61 % exhibited by chitosan beads containing a combination of
Explotab®, Ac-Di-Sol®.For all the other formulations the drug loading capacity
ranged within 48 and 63 %.
These formulations were used for dissolution studies over a period of 6 hours at pH
5.60 and 7.40. The dissolution results showed that no chitosan has dissolved at both
pH values. A significant amount of rifampicin was, however, released from the beads,
especially at pH 7.40. chitosan beads containing vitamin C also exhibited high
rifampicin release (48.34 ± 1.00) %) at pH 5.60 compared to the other formulations
and this makes vitamin C a potential excipient for enhanced drug release over a wide
pH range (both acidic and alkalinic). However, further studies are necessary to
optimise the preparation method to minimise drug loss during loading and to improve
the drug loading capacity of the beads. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2005.
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The effect of pharmaceutical excipients on the release of indomethacin from chitosan beads / Riana HavingaHavinga, Riana January 2006 (has links)
Chitosan has proven through the years as a versatile biomaterial to be used in pharmaceutical applications. Its mucoadhesive properties as well as its ability to manipulate the tight junctions in epithelium membranes have qualified it as an effective drug carrier in controlled drug delivery systems. Microparticles or beads as they are forward called in this study have advantages over conventional drug dosage forms because of a large surface to volume ratio and have the ability to target a specific site for drug release. Indomethacin is an anti-inflammatory drug that causes gastrointestinal side effects in conventional immediate-release dosage forms.
The goal is to manipulate the drug delivery vehicle to target the intestines/colon as the site for drug delivery and to minimize this side effect. Thus chitosan beads have been chosen as a drug delivery system for indomethacin in this study.
Chitosan beads have been prepared through the ionotropic gelation method using tripolyphophate (TPP) as a cross-linking agent. To prepare the most effective bead to encapsulate indomethacin different formulation and system variables (pH of the TPP solution, the concentration of the TPP solution as well as the indomethacin concentration) have been evaluated according to the following parameters: morphology, drug loading capacity and swelling capability. The ideal pH of the TPP solution was determined at 8.7 and the most effective TPP and indomethacin concentration were 5% w/v and 4% w/v respectively. The chitosan concentration was kept at 3% w/v throughout the study. These concentrations were used to examine the effect of pharmaceutical excipients on the indomethacin release from chitosan beads.
The effect of the different excipients namely, ExplotabⒽ(0.25% w/v), Ac-Di-SolⓀ (0.5% w/v) and Vitamin C (0.25% w/v), on the morphology, drug loading capacity, swelling capability as well as the drug release of indomethacin chitosan beads (ICB's) were also studied. The excipients were used in the individually above mentioned concentrations and in combination with each other in the same concentrations. These formulations were used in dissolution studies over a period of 6 hours in PBS pH 7.4 solutions. The indomethacin release rate increased when an excipient was added to the formulation and it dramatically increased when the excipients were added in their various combinations, compared to the formulation that did not contain excipients. / Contents: Chitosan -- Controlled drug delivery -- Indomethacin -- Inotropic gelation -- Tripolyphosphate (TPP) -- Explotab® -- Ac-Di-Sol® -- Vitamin C / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
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The effect of pharmaceutical excipients on rifampicin release from chitosan beads / Mangaabane Gorden MohlalaMohlala, Mangaabane Gorden January 2004 (has links)
Controlled release systems aim at achieving a predictable and reproducible drug
release over a desired time period. These systems allow reduced dosing frequency,
constant drug levels in the blood, increased patient compliance and decreased adverse
effects. In a recent study, Chitosan beads, containing N-trimethyl Chitosan chloride,
have shown a potential in the delivery of rifampicin. However, because of inadequate
amounts of rifampicin released over 24 hours, incorporation of other pharmaceutical
excipients to increase the swelling behaviour of the beads to improve drug release,
was considered in this study.
Chitosan beads were prepared through ionotropic gelation with tripolyphosphate
(TPP) as a crosslinking agent. To increase the porosity if the Chitosan beads
Explotab®, Ac-Di-Sol® and vitamin C were added individually to Chitosan solutions
at concentrations of 0.1, 0.25 and 0.5 % w/v before adding the mixture to the TPP
solution. Swelling and morphology studies were used in the evaluation of the different
formulations. The swelling and morphology results were then used to select a set of
combination and concentrations of two excipients sand then prepare and characterise
beads containing two combinations. The combination formulations and formulations
containing single excipients were then loaded with rifampicin. Pure chitosan beads
exhibited a higher drug loading capacity (67.49 %) compared to the lowest loading
capacity of 41.61 % exhibited by chitosan beads containing a combination of
Explotab®, Ac-Di-Sol®.For all the other formulations the drug loading capacity
ranged within 48 and 63 %.
These formulations were used for dissolution studies over a period of 6 hours at pH
5.60 and 7.40. The dissolution results showed that no chitosan has dissolved at both
pH values. A significant amount of rifampicin was, however, released from the beads,
especially at pH 7.40. chitosan beads containing vitamin C also exhibited high
rifampicin release (48.34 ± 1.00) %) at pH 5.60 compared to the other formulations
and this makes vitamin C a potential excipient for enhanced drug release over a wide
pH range (both acidic and alkalinic). However, further studies are necessary to
optimise the preparation method to minimise drug loss during loading and to improve
the drug loading capacity of the beads. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2005.
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The effect of pharmaceutical excipients on isoniazid release from chitosan beads / Deon van RensburgVan Rensburg, Andries Gideon January 2007 (has links)
In controlled release applications a drug is molecularly dispersed in a polymer phase. In
the presence of a thermodynamically compatible solvent, swelling occurs and the
polymer releases its content to the surrounding medium. The rate of the drug release can
be controlled by interfering with the swelling rate of the beads or by influencing diffusion
through the viscosity of the polymer.
Beads that contain chitosan were prepared through the ionotropic gelation method where
tripolyphosphate (TPP) was used as the crosslinking agent. Beads that consisted of 3%
w/v isoniazid (lNH) and 5% w/v chitosan were prepared in a 5% w/v TPP solution (pH
8.7) as the primary beads. To improve the drug loading of chitosan isoniazid beads (ClB)
the TPP concentration, pH of the TPP solution and the INH concentrations were altered
for maximum drug loading. To increase the porosity of the beads of chitosan beads
Explotab® (EXPL), Ac-Di-Sol® (ADS) and Vitamin C (VC) were added individually to
chitosan solutions at concentrations of 0.1, 0.25 and 0.5% w/v before adding the mixture
to the TPP solution. Morphology, swelling and drug loading studies were used to
evaluate the different formulations. After these excipients were added individually they
were also added in combinations of two excipients respectively and characterised. From
the results of the drug loading studies the beads that contained only chitosan and
isoniazid showed a percentage drug loading of (43.92%) which is the best of all the beads
that were analyzed. The multi excipient combination of Ac-Di-Sol® and Explotab®
showed the best swelling capability at both pH levels.
Dissolution studies were conducted on all the formu lations over a period of 6 hours (360
minutes) at pH 5.6 and pH 7.4. From the dissolution results it were clear that no chitosan
dissolved at both pH values. The dissolution of single pharmaceutical excipient (SPE)
and multi pharmaceutical excipient (MPE) formulations can be arranged in the following
order: VC/ADS < VC < ADS/EXPL < ADS < VC/EXPL < CIB < EXPL. Explotab® is a
potential excipient for enhanced drug release over a wide pH range. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2007.
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