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Gel-based solid dosage form for pesticide delivery
Dissertation (MSc)--University of Pretoria, 2008.
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University of Pretoria
2013
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| _version_ | 1867613670266109952 |
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| access_status_str | Open Access |
| author2 | Focke, Walter Wilhelm |
| author_browse | Focke, Walter Wilhelm |
| author_facet | Focke, Walter Wilhelm |
| collection | Thesis |
| dc_rights_str_mv | © 2008 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc)--University of Pretoria, 2008. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/23498 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:39:50.247Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/23498 Gel-based solid dosage form for pesticide delivery Focke, Walter Wilhelm s25496396@tuks.co.za Massinga, Pedro Horacio Cypermethrin Solid dosage form Gel Emulsion UCTD Dissertation (MSc)--University of Pretoria, 2008. The aim of this research was to develop a solid dosage form containing 1.5 g of the pesticide cypermethrin. The dosage should be stable in a tropical climate. In addition, it is to disintegrate and disperse in 10 L of tap water within 3 minutes. Such dissolution should yield a 150 ppm dispersion of cypermethrin, stable for at least one week. This provides for a dip dispersion to treat ticks and fly infestation on livestock. A new solid dosage was formulated as the scope of this research. It is a gel-based solid dosage form. Polymer electrolyte ASP4 - a copolymer of methacrylic acid, ethyl acrylate and diethyl maleate, was used to produce the gel. Preliminary tests revealed that ASP4- based gel, on its own, failed to meet the required dissolution time of 3 minutes. Strong entanglements of ASP4 chains impeded rapid dissolution. These strong entanglements occurred owing to the use of a high concentration of ASP4. Reducing the concentration of ASP4 yielded a solution of high viscosity instead of a gel. It was therefore decided to Gel-based solid dosage form for pesticide delivery use a superabsorbent (Product Z1069) in conjunction with ASP4 to produce the gel. Product Z1069 is a cross-linked sodium polyacrylate. Before producing the gel, a 1:1.5 by mass oil/water (O/W) emulsion was prepared using the phase-inversion route. The water (W) phase comprised 85.9% distilled water, 3.9% ASP4 at 20% dispersion, 8.6% sodium carbonate (0.5 M) and 1.6% Emulsogen EL. All concentrations are indicated in mass %. The oil (O) phase consisted of 76.9% cypermethrin, 19.3% Solvesso S200 and 3.8% Phenyl Sulphonate CA, also by mass. This emulsion was gelled by adding the superabsorbent Product Z1069 (ca. 37.5% by mass relative to the W phase of the emulsion). The superabsorbent strongly absorbed water, depleting it from the emulsion. This resulted in an increase of the effective concentration of ASP4 in the water phase of the emulsion. This increase of the polymer electrolyte concentration brought about a gel-like state corresponding to the desired solid dosage form. Rheometry confirmed that the dosage form maintained a solid gel-like consistency at 50°C. The dosage contained 24.6% m/m cypermethrin. Thus, the required dosage of 1.5 g was achieved in pellets weighing ca. 6.1 g. Such pellets rapidly disintegrated with mild stirring in 10 L of tap water. Complete pellet disintegration and active dispersion occurred within 2.5 minutes at ambient temperature (25 ± 2°C). Chemistry unrestricted 2013-09-06T15:28:27Z 2008-10-28 2013-09-06T15:28:27Z 2008-09-03 2008 2008-03-26 Dissertation Massinga Junior, PH 2008, Gel-based solid dosage form for pesticide delivery, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/23498 > C108/ag http://hdl.handle.net/2263/23498 http://upetd.up.ac.za/thesis/available/etd-03262008-103857/ © 2008 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Cypermethrin Solid dosage form Gel Emulsion UCTD Gel-based solid dosage form for pesticide delivery |
| title | Gel-based solid dosage form for pesticide delivery |
| title_full | Gel-based solid dosage form for pesticide delivery |
| title_fullStr | Gel-based solid dosage form for pesticide delivery |
| title_full_unstemmed | Gel-based solid dosage form for pesticide delivery |
| title_short | Gel-based solid dosage form for pesticide delivery |
| title_sort | gel based solid dosage form for pesticide delivery |
| topic | Cypermethrin Solid dosage form Gel Emulsion UCTD |
| url | http://hdl.handle.net/2263/23498 http://upetd.up.ac.za/thesis/available/etd-03262008-103857/ |