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Investigations into sustained-release hydrophobic matrix pellet formulationsLee, Jobina J. N. January 2003 (has links)
No description available.
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Extrusion-Spheronization of Talc using Microcrystalline Cellulose as a Pellet Aid: Part IJadhav, N., Gade, M., Salunkhe, N., Paradkar, Anant R 12 1900 (has links)
No / The aims of the present work were to pelletize talc by extrusion-spheronization technique using microcrystalline cellulose (MCC) as a pelletization aid and to study its performance as a neutral substrate for coating. A 32 factorial design was used to study the effect of independent variables (X1, amount of talc, and X2, MCC) on pellet properties.
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Preparation and evaluation of multiple-unit solid oral dosage forms containing chemical permeation enhancing agents / Elmarie KleynhansKleynhans, Elmarie January 2014 (has links)
The most popular and convenient route of drug administration remains the oral route,
however, protein and peptide drugs such as insulin have poor membrane permeability and
stability in the gastrointestinal tract. Absorption enhancers can be added to drug delivery
systems to overcome the epithelial cell membrane permeability problem. Although previous
studies have shown that aloe leaf materials improve the transport of drugs across intestinal
epithelia, their performance in solid oral dosage forms has not yet been investigated.
Beads containing insulin and each of the selected absorption enhancers (i.e. Aloe ferox,
Aloe marlothii and Aloe vera gel materials) were produced by extrusion-spheronisation,
using a full factorial design to optimise the formulations based on transepithelial electrical
resistance (TEER) reduction of Caco-2 cell monolayers as response. The optimum bead
formulations were evaluated in terms of friability, mass variation, particle surface texture,
shape, size and dissolution. The transport of insulin across excised pig intestinal tissue from
the optimised bead formulations was determined over a 2 h period. The samples obtained
from the transport studies were analysed for insulin content by means of high-performance
liquid chromatography (HPLC).
The results showed that the TEER reduction, as an indication of tight junction modulation,
obtained for the bead formulations containing aloe materials was concentration dependent.
Furthermore, inclusion of croscarmellose sodium (Ac-di-sol®) as a disintegrant showed an
enhanced TEER reduction effect in combination with the aloe gel materials. Dissolution
profiles indicated that the beads containing aloe leaf materials in conjunction with insulin,
released the insulin within an hour. In accordance with the TEER reduction results, the
A. marlothii and A. vera materials containing beads showed similar increased insulin delivery
across excised pig intestinal tissue, which was pronouncedly higher than that of the control
group (insulin alone).
It can be concluded that beads containing aloe leaf materials have high potential as effective
delivery systems for protein therapeutics such as insulin via the oral route of administration. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2015
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Preparation and evaluation of multiple-unit solid oral dosage forms containing chemical permeation enhancing agents / Elmarie KleynhansKleynhans, Elmarie January 2014 (has links)
The most popular and convenient route of drug administration remains the oral route,
however, protein and peptide drugs such as insulin have poor membrane permeability and
stability in the gastrointestinal tract. Absorption enhancers can be added to drug delivery
systems to overcome the epithelial cell membrane permeability problem. Although previous
studies have shown that aloe leaf materials improve the transport of drugs across intestinal
epithelia, their performance in solid oral dosage forms has not yet been investigated.
Beads containing insulin and each of the selected absorption enhancers (i.e. Aloe ferox,
Aloe marlothii and Aloe vera gel materials) were produced by extrusion-spheronisation,
using a full factorial design to optimise the formulations based on transepithelial electrical
resistance (TEER) reduction of Caco-2 cell monolayers as response. The optimum bead
formulations were evaluated in terms of friability, mass variation, particle surface texture,
shape, size and dissolution. The transport of insulin across excised pig intestinal tissue from
the optimised bead formulations was determined over a 2 h period. The samples obtained
from the transport studies were analysed for insulin content by means of high-performance
liquid chromatography (HPLC).
The results showed that the TEER reduction, as an indication of tight junction modulation,
obtained for the bead formulations containing aloe materials was concentration dependent.
Furthermore, inclusion of croscarmellose sodium (Ac-di-sol®) as a disintegrant showed an
enhanced TEER reduction effect in combination with the aloe gel materials. Dissolution
profiles indicated that the beads containing aloe leaf materials in conjunction with insulin,
released the insulin within an hour. In accordance with the TEER reduction results, the
A. marlothii and A. vera materials containing beads showed similar increased insulin delivery
across excised pig intestinal tissue, which was pronouncedly higher than that of the control
group (insulin alone).
It can be concluded that beads containing aloe leaf materials have high potential as effective
delivery systems for protein therapeutics such as insulin via the oral route of administration. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2015
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Use of Aloe vera and Aloe marlothii materials as excipients in beads produced by extrusion-spheronization / Patience Chinyemba.Chinyemba, Patience January 2012 (has links)
Microcrystalline cellulose (MCC) is the most commonly used excipient in the manufacture of spherical particles or beads by extrusion spheronisation. However, the use of MCC in beads has its limitations such as prolonged release of drugs due to lack of disintegration. The aim of this study was to determine if Aloe vera and Aloe marlothii leaf materials can be used as excipients in the production of beads prepared by extrusion spheronisation. A 23 full factorial design was employed for optimisation and to explore the effects of the concentration of MCC, polyvinylpyrrolidone and aloe materials on the sphericity and release rate of ketoprofen. Scanning electron microscopy revealed more porous beads when aloe materials were included in the bead formulations compared to the formulation with MMC alone. The bead formulations containing aloe materials exhibited faster drug release compared to that of the formulation containing MCC alone. Dissolution data of the optimised formulations were analysed in terms of mean dissolution time (MDT) as well as fit factors (f1 and f2). The optimised bead formulations had dissolution profiles comparable to that of the formulation containing MCC alone at pH 1.2 and 4.5 (f2 values > 70), but less comparable to the reference at pH 6.8 (50 < f2< 65) due to faster drug release. Aloe vera and Aloe marlothii leaf materials can be used successfully together with MCC in the production of beads by extrusion spheronisation. / Thesis (MSc (Pharmaceutics))--North-West University, Potchefstroom Campus, 2013.
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Use of Aloe vera and Aloe marlothii materials as excipients in beads produced by extrusion-spheronization / Patience Chinyemba.Chinyemba, Patience January 2012 (has links)
Microcrystalline cellulose (MCC) is the most commonly used excipient in the manufacture of spherical particles or beads by extrusion spheronisation. However, the use of MCC in beads has its limitations such as prolonged release of drugs due to lack of disintegration. The aim of this study was to determine if Aloe vera and Aloe marlothii leaf materials can be used as excipients in the production of beads prepared by extrusion spheronisation. A 23 full factorial design was employed for optimisation and to explore the effects of the concentration of MCC, polyvinylpyrrolidone and aloe materials on the sphericity and release rate of ketoprofen. Scanning electron microscopy revealed more porous beads when aloe materials were included in the bead formulations compared to the formulation with MMC alone. The bead formulations containing aloe materials exhibited faster drug release compared to that of the formulation containing MCC alone. Dissolution data of the optimised formulations were analysed in terms of mean dissolution time (MDT) as well as fit factors (f1 and f2). The optimised bead formulations had dissolution profiles comparable to that of the formulation containing MCC alone at pH 1.2 and 4.5 (f2 values > 70), but less comparable to the reference at pH 6.8 (50 < f2< 65) due to faster drug release. Aloe vera and Aloe marlothii leaf materials can be used successfully together with MCC in the production of beads by extrusion spheronisation. / Thesis (MSc (Pharmaceutics))--North-West University, Potchefstroom Campus, 2013.
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Extrusion-sphéronisation de produits pharmaceutiques : comparaison et transposition à échelle industrielle de procédés d’extrusion par plans d’expériences / Extrusion-spheronisation of pharmaceutical products : comparison and industrial scaling-up of extrusion processes by a design of experiments approachDésire, Amélie 06 September 2011 (has links)
Parmi les différents procédés d’élaboration de minigranules, le procédé d’extrusion-sphéronisation présente de nombreux avantages, puisqu’il permet notamment d’élaborer des minigranules fortement chargées en principe actif et d’éviter l’emploi de solvants organiques. Ce travail a pour objectif de comparer les performances de plusieurs systèmes d’extrusion à vis, de l’échelle du laboratoire jusqu’à la transposition à l’échelle industrielle. Pour cela, des plans d’expériences ont été construits afin d’identifier les variables critiques et de sélectionner l’extrudeur le plus favorable selon différentes approches spécifiques à cette étude. En effet, le système d’extrusion idéal est défini dans ce travail comme celui donnant les meilleurs résultats en termes de productivité et de caractéristiques des minigranules (« qualité »), entraînant le moins d’impact sur le produit après transposition d’échelle (« transposabilité »), montrant le moins d’influence sur le produit lorsque la formule utilisée change (« robustesse »), et permettant d’ajuster ou d’améliorer la qualité des minigranules lorsque les conditions opératoires varient (« flexibilité »). Quelle que soit l’approche étudiée, les résultats ont permis de mettre en évidence l’influence de paramètres critiques et de leurs interactions sur les différentes réponses et ont montré des différences entre les différents systèmes d’extrusion. L’étude à l’échelle du laboratoire a permis de comparer les extrudeurs radial, dôme et frontal et a mis en évidence l’intérêt des systèmes frontal et dôme en termes de qualité des minigranules, et du système radial en termes de robustesse et de flexibilité du procédé. L’étude à l’échelle industrielle a permis de comparer les extrudeurs radial et frontal, et a permis d’identifier l’extrudeur frontal comme étant le plus favorable en termes de qualité des minigranules, de robustesse, de flexibilité et de transposabilité. Les conclusions observées à l’échelle industrielle sont donc différentes de celles considérées à l’échelle du laboratoire, pour l’étude comparative des différents systèmes. Cela confirme l’importance de tester les systèmes à échelle industrielle avant l’acquisition d’un équipement. / Among the various methods of developing minigranules, extrusion-spheronization has many advantages, particularly since it allows to develop minigranules highly charged with active pharmaceutical ingredient and to avoid the use of organic solvents. This work aims to compare the performance of several extrusion screws systems, from the lab to the scale-up at industrial scale. Designs of experiments were built to identify critical variables and compare the extruder in terms of different approaches specific to this study. As a matter of fact, the ideal extrusion system is defined in this work as the one which gives the best results in terms of productivity and pellets characteristics (“quality”), the one which shows less impact on the product after scaling-up (“scalability”), the one which shows the less influence on these same properties when the formula used changes (“robustness”), and the one which allows the possibility to adjust or improve pellets properties with operating variables (“flexibility”). Whatever the approach studied, the results allowed to highlight the influence of critical parameters and their interactions on the different responses and showed differences between the different extrusion systems. The study at lab scale compared radial, dome and axial extruders and underlined the interest of axial and dome systems in terms of pellets quality, and radial system in terms of process robustness and flexibility. The study at industrial scale compared radial and axial systems, and identified the axial system as the most favorable in terms of pellets quality , robustness, flexibility and scalability. The conclusions observed at industrial scale are different from those observed at lab scale for the different systems comparative study. This confirms the importance to test systems at industrial scale before investing in one equipment.
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Preparation of Tablets from Reservoir Pellets with an Emphasis on the Compression Behaviour and Drug ReleaseTunón, Åsa January 2003 (has links)
<p>The preparation of multiple unit tablets was investigated in this thesis with the intention of gaining a deeper understanding of some of the factors that influence the properties of such tablets.</p><p>Initially, three different types of pellets (drug, soft and disintegrant pellets) were combined as a model to investigate the ability of the mixture to form disintegrating tablets. The proportions of the different pellets and the type of disintegrant used were factors that independently influenced the tablet properties. Furthermore, the properties of tablets containing drug pellets barrier-coated with an aqueous polymer dispersion were also found to depend on the coating thickness and the compaction pressure.</p><p>When compacting pellets barrier-coated with a solvent-based polymer solution without incorporating excipient particles in the tablet formulation, a high pellet porosity was advantageous to preserve the original drug release profile, even though highly porous pellets became more densified and deformed than pellets of lower porosity.</p><p>The influence of the properties of excipient particles on the deformation<b> </b>of the reservoir pellets was also studied and, although the amount of flattening of the pellets was only slightly affected, changes in the pellet shape (irregularity) with alterations in the porosity and size of the excipient particles were more substantial. In contrast, the properties of the excipient particles did not affect the pellet densification.</p><p>The solvent-based coating used was able to adapt to the changes in volume and shape that the pellets underwent during compaction. The coating structure appears to be changed by compaction and it is proposed that the final structure of the coating is the net effect of two parallel processes, one reducing and one prolonging the transport time of the drug across the coating. Thus, the drug release could be maintained or even prolonged after compaction, despite extensive structural changes of the reservoir pellets.</p>
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Preparation of Tablets from Reservoir Pellets with an Emphasis on the Compression Behaviour and Drug ReleaseTunón, Åsa January 2003 (has links)
The preparation of multiple unit tablets was investigated in this thesis with the intention of gaining a deeper understanding of some of the factors that influence the properties of such tablets. Initially, three different types of pellets (drug, soft and disintegrant pellets) were combined as a model to investigate the ability of the mixture to form disintegrating tablets. The proportions of the different pellets and the type of disintegrant used were factors that independently influenced the tablet properties. Furthermore, the properties of tablets containing drug pellets barrier-coated with an aqueous polymer dispersion were also found to depend on the coating thickness and the compaction pressure. When compacting pellets barrier-coated with a solvent-based polymer solution without incorporating excipient particles in the tablet formulation, a high pellet porosity was advantageous to preserve the original drug release profile, even though highly porous pellets became more densified and deformed than pellets of lower porosity. The influence of the properties of excipient particles on the deformation<b> </b>of the reservoir pellets was also studied and, although the amount of flattening of the pellets was only slightly affected, changes in the pellet shape (irregularity) with alterations in the porosity and size of the excipient particles were more substantial. In contrast, the properties of the excipient particles did not affect the pellet densification. The solvent-based coating used was able to adapt to the changes in volume and shape that the pellets underwent during compaction. The coating structure appears to be changed by compaction and it is proposed that the final structure of the coating is the net effect of two parallel processes, one reducing and one prolonging the transport time of the drug across the coating. Thus, the drug release could be maintained or even prolonged after compaction, despite extensive structural changes of the reservoir pellets.
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Evaluation of the critical parameters and polymeric coat performance in compressed multiparticulate systemsBenhadia, Abrehem M.A. January 2019 (has links)
Compression of coated pellets is a practical alternative to capsule filling. The
current practice is to add cushioning agents to minimize the stress on the
coated pellets. Cushioning agents however add bulkiness and reduce the
overall drug loading capacity. In this study, we investigated the performance
of compressed coated pellets with no cushioning agent to evaluate the
feasibility of predicting the coat behaviour using thermo-mechanical and
rheological analysis techniques. Different coating formulations were made of
ethyl cellulose (EC) as a coating polymer and two different kinds of additives
were incorporated into the polymeric coating solution. Triethyl Citrate (TEC)
and Polyethylene glycol 400(PEG400) were used as plasticizers at different
levels to the coating formulations (10%, 20%, 30%). Thermal, mechanical
and rheological measurements of the coating film formulations were
achieved to investigate the effect of plasticizers. Thermal gravimetric
analysis results (TGA) showed higher residual moisture content in films
plasticised with PEG 400 compared to their TEC counterparts. Differential
Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA) and
Parallel Plate Shear Rheometer (PPSR) were used to study the influence of
the level and type of plasticisers incorporated in coating film formulation on
the performance of the coating film. In this study, both DSC and DMA were used to investigate the Tg for each film coating formulation in order to
evaluate the effect of the additives. In general DMA results for the Tg value
of the films were always higher by 10-20% than those measured by the DSC.
Furthermore, clamp size and the frequency of the oscillation have an
influence on the evaluation of Tg. Complex viscosity for different coating film
formulations revealed that the shear hinning gradient changes with
temperature and plasticiser type and concentration. The value of complex
viscosity from DMA and PPSR exhibits power law behaviour. The rheological
moduli were indirectly affected by the level of plasticiser. There was a
discrepancy between the complex viscosity results obtained from both DMA
and PPSR at similar temperature but they follow the same trend. The non
plasticized polymer showed a 10 time higher complex viscosity values when
measured by DMA over that measured by PPSR. The difference was smaller
in plasticized films but it was not consistent. Therefore a consistent
coefficient to correlate the DMA and PPSR couldn’t be accurately determined
Coated pellets were compressed and key process parameters were
evaluated. The obtained results revealed that the coating thickness has a
significant effect on the release profile of the final products. It was found that
by increasing the coating film thickness, the percentage released decreased.
Also the compression force has lower influence on the drug release profile,
while the dwell time has very low effect on the percentage release from the
final products. Optimum release profile was obtained at a coating level of 5.5%
w/w and a compression force of 4700N
In conclusion, the elasticity of the plasticised EC films in this study meant
that the internal stress is not dissipated during compression and the dwell time range that was used in this experiment. Increasing the thickness
therefore was necessary to enhance the strength of the film and avoid
cracking. The mechanical and rheological profiling was helpful therefore to
understand the behaviour of the coated pellets and predict the film properties
at various steps of the process of coating and compression (i.e., various
shear rate regimes). Experimental design approach to studying the key
process and formulation parameters helped identify the optimum values for
the process.
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