Malaria is a life–threatening disease caused by Plasmodium spp and causes over one million
deaths annually. The complex life cycle of the malaria parasite offers several points of attack
for the antimalarial drugs. The rapid spread of resistance against antimalarial drugs, especially
chloroquine and pyrimethamine–sulphadoxine, emphasises the need for new alternatives or
modification of existing drugs. Artemisinin–based combination therapies (ACT’s) with different
targets prevent or delay the development of drug resistance and therefore have been adopted
as first–line therapy by all endemic countries. Proguanil–dapsone, an antifolate combination is
more active than pyrimethamine–sulphadoxine and is being considered as an alternative to
pyrimethamine–sulphadoxine. Artesunate–proguanil–dapsone is a new ACT that has wellmatched
pharmacokinetics and is relatively rapidly eliminated; therefore there is a reduced risk
of exposure to any single compound and potentially a decreasing risk of resistance. A few
studies have been done on a triple fixed–dose combination therapy for malaria treatment and
such a combination for artesunate, proguanil and dapsone are not currently investigated,
manufactured or distributed. The aim of this study was to develop a triple fixed–dose
combination for artesunate, proguanil and dapsone.
The formulation was developed in three phases; basic formulation development, employing
factorial design to obtain two possible optimised formulations and evaluating the optimised
formulations. During the formulation development the most suitable manufacturing procedure
and excipients were selected. A full 24 factorial design (four factors at two levels) was used to
obtain the optimised formulations. As end–points to identify the optimised formulations, weight
variation, friability, crushing strength and disintegration of the tablets, were used. Statistical
analysis (one way ANOVA) was used to identify optimal formulations. To identify any
interaction between the active pharmaceutical ingredients (API’s) and the API’s and excipients,
differential scanning calorimetry was done. Flow properties of the powder mixtures (of the
optimised formulations) were characterised by means of angle of repose; critical orifice diameter
(COD); bulk density and tapped density; and flow rate. Tablets of the two optimised powder
formulations were compressed. The tablets were evaluated and characterised in terms of
weight variation, friability, crushing strength, disintegration and dissolution behaviour. Initial
formulation development indicated that wet granulation was the most suitable manufacturing method. The results from the factorial design indicated that different amounts (% w/w) of the
lubricant and binder as well as two different fillers influenced the weight variation, crushing
strength and disintegration statistically significant. Two formulations containing two different
fillers (microcrystalline cellulose or Avicel® PH 101, and lactose or Granulac® 200) were found to
be within specifications and ideal for manufacturing.
Tablets prepared from the FA formulation (formulation containing Avicel® PH 101) complied with
the standards and guidelines for weight variation, friability, crushing strength and disintegration
as set by the British Pharmacopoeia (BP). Tablets had an average crushing strength of 121.56
± 0.022 N. Tablets disintegrated within 52.00 seconds and a maximum weight loss of 0.68%
occurred during the friability test. Weight variation of the tablets prepared from the FG
formulation (formulation containing Granulac® 200) complied with the standards. Average
crushing strength was 91.99 ± 6.008 N and the tablets disintegrated within 140.00 seconds.
Percentage friability (1.024%) did not comply with the guideline of a percentage friability of less
than 1%, however, no cracked or broken tablets were seen.
Dissolution showed that 98, 93 and 94% of artesunate, proguanil and dapsone were
respectively released (of the label value) within 15 minutes for the FA formulations. Release of
artesunate, proguanil and dapsone for the FG formulation was 62, 85 and 92% for the same
time period. The release of the three API’s (the FG formulation) increased to 78, 89 and 92%, respectively, after 45 minutes. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2012.
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/7579 |
| Date | January 2011 |
| Creators | Van der Merwe, Adriana Johanna |
| Publisher | North-West University |
| Source Sets | North-West University |
| Detected Language | English |
| Type | Thesis |
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