Rheological characterization of pharmaceutical semisolids is of importance as it provides fundamental information required for the assessment of some of the final properties of a product such as viscosity, elasticity, quality and storage stability. The effect of formulation variables on product characteristics such as consistency and correlation of consumer evaluation of consistency can also be attained. (Ramachandran et al., 1999) This study focussed on using rheological techniques to fully characterize the properties of various semisolid formulations being developed or produced at a South African-based generic pharmaceutical company. Various tests were employed to characterize the semisolid dosage forms (creams and ointments), including continuous shear tests such as flow and viscosity curves and yield point measurements, oscillatory tests such as amplitude and frequency sweeps, as well as step and temperature ramp tests. A method to determine justifiable and meaningful viscosity specifications was developed, where excellent reproducibility of results were obtained when compared to the single-point viscosity determinations usually used. An evaluation as to whether rheology can be utilized as an assessment tool for product stability revealed varying results, with the oscillation-frequency sweep test displaying modest predictive capabilities. Observable differences in rheological character were found when evaluating ointment formulations exhibiting deviating quality characteristics. When analysing the effect of varying processing parameters, namely, cooling rate and mixing speed, during the manufacture of a cream, statistically significant rheological differences were obtained, while a thorough characterization of a scale-up procedure was also achieved upon analysis of various rheological properties.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nmmu/vital:10128 |
| Date | January 2004 |
| Creators | Jaganath, Nelesh |
| Publisher | Nelson Mandela Metropolitan University, Faculty of Health Sciences |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MSc |
| Format | 288 pages, pdf |
| Rights | Nelson Mandela Metropolitan University |
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