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Summers MP, Verikios G. Assistive technology pricing in Australia: is it efficient and equitable? AUST HEALTH REV 2019; 42:100-110. [PMID: 28160784 DOI: 10.1071/ah16042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 12/09/2016] [Indexed: 11/23/2022]
Abstract
Objective To examine available systematically collected evidence regarding prices for assistive technology (AT; e.g. disability aids and equipment) in Australia with other comparable countries. Issues of appropriate AT pricing are coming to the fore as a consequence of efforts to move to consumer-centric purchasing decisions with the National Disability Insurance Scheme (NDIS) and also in the recent aged care reforms. Methods We identified and present three sets of AT price comparisons. Two comparisons were based solely on the lowest prices advertised on the internet, and one comparison examined recommended retail prices. Variables essential to ensuring accurate comparisons, as well as significant supply-chain issues were also examined and considered in the analyses. Results The first internet-only price comparison found that overall AT prices were 38% higher in Australia compared to other countries, but did not factor in shipping and other related costs that are essential to include given that most AT is imported. The second internet-only price comparison found that overall Australian prices were 24% lower when shipping and related costs were included. The recommended retail price comparisons found that Australian prices were between 14% and 27% lower. Prices for internet-only retailers (those with no bricks-and-mortar presence) are consistently lower for all products than those sold by retailers with actual shop-fronts. Further, there is no evidence of suppliers earning supranormal profits in Australia. Conclusions The results indicate that AT prices in Australia are efficient and equitable, with no significant indicators of market failure which would require government intervention. Efforts to reduce prices through the excessive use of large-scale government procurement programs are likely to reduce diversity and innovation in AT and raise AT prices over time. Open markets and competition with centralised tracking of purchases and providers to minimise possible over-servicing/over-charging align well with the original intention of the NDIS, and are likely to yield the best outcomes for consumers at the lowest costs. What is known about the topic? Government-funded programs are used extensively to purchase AT because it is a primary enabler for people of all ages with disabilities. Perceptions of unreasonably high prices for AT in Australia are resulting in the widespread adoption of bulk purchasing and related strategies by governments. What does this paper add? Carefully undertaken systematic price comparisons between Australia and comparable Organization For Economic Cooperation and Development countries indicate that, on average, Australian prices are lower than elsewhere when delivery to Australia is taken into account. It was also found that prices at brick-and-mortar shops, with all the services they provide to ensure the appropriateness of the products provided to meet the consumers' needs and goals, are substantially higher than Internet purchases in which the consumer bears all the risks and responsibilities for outcomes. What are the implications? Overuse of government bulk purchasing and similar arrangements will lead to less diversity in the available AT products, related services and retail outlets, resulting in less choice for consumers and higher risks of poor outcomes through less focus on matching consumers with the 'right' products for their needs and goals, and ultimately higher AT prices over time as competition is reduced to a few major suppliers.
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Affiliation(s)
- Michael P Summers
- Centre for Health Communication and Participation, Australian Institute for Primary Care and Ageing, La Trobe University, Bundoora, Vic. 3086, Australia. Email
| | - George Verikios
- KPMG Economics, 71 Eagle Street, Brisbane, QLD 4000, Australia
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Synnot AJ, Cherry CL, Summers MP, Stuckey R, Milne CA, Lowe DB, Hill SJ. Consumer engagement critical to success in an Australian research project: reflections from those involved. Aust J Prim Health 2019; 24:197-203. [PMID: 29875031 DOI: 10.1071/py17107] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/08/2018] [Indexed: 11/23/2022]
Abstract
This paper describes the people, activities and methods of consumer engagement in a complex research project, and reflects on the influence this had on the research and people involved, and enablers and challenges of engagement. The 2.5-year Integrating and Deriving Evidence Experiences and Preferences (IN-DEEP) study was conducted to develop online consumer summaries of multiple sclerosis (MS) treatment evidence in partnership with a three-member consumer advisory group. Engagement methods included 6-monthly face-to-face meetings and email contact. Advisory group members were active in planning, conduct and dissemination and translational phases of the research. Engaging consumers in this way improved the quality of the research process and outputs by: being more responsive to, and reflective of, the experiences of Australians with MS; expanding the research reach and depth; and improving the researchers' capacity to manage study challenges. Advisory group members found contributing their expertise to MS research satisfying and empowering, whereas researchers gained confidence in the research direction. Managing the unpredictability of MS was a substantive challenge; the key enabler was the 'brokering role' of the researcher based at an MS organisation. Meaningfully engaging consumers with a range of skills, experiences and networks can make important and unforeseen contributions to research success.
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Affiliation(s)
- Anneliese J Synnot
- Centre for Health Communication and Participation, School of Psychology and Public Health, College of Science, Health and Engineering, La Trobe University, Kingsbury Drive, Bundoora, Vic. 3068, Australia
| | - Catherine L Cherry
- Centre for Biomedical Research, Burnet Institute 85 Commercial Road, Melbourne, Vic. 3004, Australia
| | - Michael P Summers
- Centre for Health Communication and Participation, School of Psychology and Public Health, College of Science, Health and Engineering, La Trobe University, Kingsbury Drive, Bundoora, Vic. 3068, Australia
| | - Rwth Stuckey
- Centre for Ergonomics and Human Factors, School of Psychology and Public Health, College of Science, Health and Engineering, La Trobe University, Kingsbury Drive, Bundoora, Melbourne, Vic. 3086, Australia
| | - Catherine A Milne
- Sydney Health Ethics, School of Public Health, University of Sydney, Sydney, NSW 2006, Australia
| | - Dianne B Lowe
- Centre for Health Communication and Participation, School of Psychology and Public Health, College of Science, Health and Engineering, La Trobe University, Kingsbury Drive, Bundoora, Vic. 3068, Australia
| | - Sophie J Hill
- Centre for Health Communication and Participation, School of Psychology and Public Health, College of Science, Health and Engineering, La Trobe University, Kingsbury Drive, Bundoora, Vic. 3068, Australia
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Synnot AJ, Hawkins M, Merner BA, Summers MP, Filippini G, Osborne RH, Shapland SD, Cherry CL, Stuckey R, Milne CA, Mosconi P, Colombo C, Hill SJ. Producing an evidence-based treatment information website in partnership with people affected by multiple sclerosis. Health Sci Rep 2018; 1:e24. [PMID: 30623063 PMCID: PMC6266475 DOI: 10.1002/hsr2.24] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 11/29/2017] [Accepted: 12/12/2017] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND AND AIMS In earlier work, we identified that people affected by multiple sclerosis (MS) can have difficulty finding online treatment information that is up to date, trustworthy, understandable, and applicable to personal circumstances, but does not provoke confusion or negative emotional consequences. The objective was to develop online consumer summaries of MS treatment evidence (derived from Cochrane Reviews) that respond to identified treatment information needs of people affected by MS. METHODS A 2-phase mixed-methods project, conducted in partnership with consumers and an MS organisation. Phase 1 included review panels with consumers (Australians affected by MS) and health professionals to test paper-based treatment summaries before development, and pilot testing of the website. Phase 2 involved an online survey after website launch. RESULTS Eighty-three participants (85% affected by MS) took part. Phase 1 participants strongly endorsed key review summary components, including layering information, and additional sections to aid personal applicability. Participants additionally suggested questions for health professionals. Participants across both phases were receptive to the idea of being provided with Cochrane Review summaries online but were seeking other types of evidence and information, such as personal experiences and the latest experimental treatments, which could not be provided. While the small survey sample size (n = 58) limits application of the results to a broader population, the website was viewed favourably, as a useful, understandable, and trustworthy information source. CONCLUSION We describe a partnership approach to developing online evidence-based treatment information, underpinned by an in-depth understanding of consumers' information needs.
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Affiliation(s)
- Anneliese J. Synnot
- Centre for Health Communication and Participation, School of Psychology and Public HealthLa Trobe UniversityMelbourneAustralia
- Cochrane Australia, School of Public Health and Preventive MedicineMonash UniversityMelbourneAustralia
| | - Melanie Hawkins
- Health Systems Improvement Unit, Centre for Population Health Research, School of Health and Social DevelopmentDeakin UniversityGeelongAustralia
| | - Bronwen A. Merner
- Centre for Health Communication and Participation, School of Psychology and Public HealthLa Trobe UniversityMelbourneAustralia
| | - Michael P. Summers
- Centre for Health Communication and Participation, School of Psychology and Public HealthLa Trobe UniversityMelbourneAustralia
| | - Graziella Filippini
- Cochrane Multiple Sclerosis and Rare Diseases of the Central Nervous System Review Group, Scientific DirectionIRCCS Foundation Neurological Institute Carlo BestaMilanItaly
| | - Richard H. Osborne
- Health Systems Improvement Unit, Centre for Population Health Research, School of Health and Social DevelopmentDeakin UniversityGeelongAustralia
| | | | - Catherine L. Cherry
- Burnet Institute, Department of Infectious DiseasesThe Alfred Hospital and Monash UniversityMelbourneAustralia
- Faculty of Health SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
| | - Rwth Stuckey
- Centre for Ergonomics and Human Factors, School of Psychology and Public HealthLa Trobe UniversityMelbourneAustralia
| | - Catherine A. Milne
- Centre for Values, Ethics and Law in MedicineUniversity of SydneySydneyNew South WalesAustralia
| | - Paola Mosconi
- Laboratory for Medical Research and Consumer Involvement, Department of Public HealthIRCCS Istituto di Ricerche Farmacologiche Mario NegriMilanItaly
| | - Cinzia Colombo
- Laboratory for Medical Research and Consumer Involvement, Department of Public HealthIRCCS Istituto di Ricerche Farmacologiche Mario NegriMilanItaly
| | - Sophie J. Hill
- Centre for Health Communication and Participation, School of Psychology and Public HealthLa Trobe UniversityMelbourneAustralia
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Synnot AJ, Hill SJ, Garner KA, Summers MP, Filippini G, Osborne RH, Shapland SD, Colombo C, Mosconi P. Online health information seeking: how people with multiple sclerosis find, assess and integrate treatment information to manage their health. Health Expect 2016; 19:727-37. [PMID: 25165024 PMCID: PMC5055229 DOI: 10.1111/hex.12253] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2014] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND OBJECTIVE The Internet is increasingly prominent as a source of health information for people with multiple sclerosis (MS). But there has been little exploration of the needs, experiences and preferences of people with MS for integrating treatment information into decision making, in the context of searching on the Internet. This was the aim of our study. DESIGN Sixty participants (51 people with MS; nine family members) took part in a focus group or online forum. They were asked to describe how they find and assess reliable treatment information (particularly online) and how this changes over time. Thematic analysis was underpinned by a coding frame. RESULTS Participants described that there was both too much information online and too little that applied to them. They spoke of wariness and scepticism but also empowerment. The availability of up-to-date and unbiased treatment information, including practical and lifestyle-related information, was important to many. Many participants were keen to engage in a 'research partnership' with health professionals and developed a range of strategies to enhance the trustworthiness of online information. We use the term 'self-regulation' to capture the variations in information seeking behaviour that participants described over time, as they responded to their changing information needs, their emotional state and growing expertise about MS. CONCLUSIONS People with MS have developed a number of strategies to both find and integrate treatment information from a range of sources. Their reflections informed the development of an evidence-based consumer web site based on summaries of MS Cochrane reviews.
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Affiliation(s)
- Anneliese J. Synnot
- Centre for Health Communication and ParticipationDepartment of Public HealthSchool of Public Health and Human BiosciencesLa Trobe UniversityMelbourneVic.Australia
| | - Sophie J. Hill
- Centre for Health Communication and ParticipationDepartment of Public HealthSchool of Public Health and Human BiosciencesLa Trobe UniversityMelbourneVic.Australia
| | - Kerryn A. Garner
- Centre for Health Communication and ParticipationDepartment of Public HealthSchool of Public Health and Human BiosciencesLa Trobe UniversityMelbourneVic.Australia
| | - Michael P. Summers
- Centre for Health Communication and ParticipationDepartment of Public HealthSchool of Public Health and Human BiosciencesLa Trobe UniversityMelbourneVic.Australia
| | - Graziella Filippini
- Cochrane Multiple Sclerosis and Rare Diseases of the Central Nervous System Review GroupUnit of NeuroepidemiologyFondazione IRCCS Istituto Neurologico, C. BestaMilanItaly
| | - Richard H. Osborne
- Public Health InnovationPopulation Health Strategic Research CentreSchool of Health and Social DevelopmentDeakin UniversityMelbourneVic.Australia
| | | | - Cinzia Colombo
- Laboratory for medical research and consumer involvementDepartment of Public HealthIRCSS‐Mario NegriInstitute for Pharmacological ResearchMilanItaly
| | - Paola Mosconi
- Laboratory for medical research and consumer involvementDepartment of Public HealthIRCSS‐Mario NegriInstitute for Pharmacological ResearchMilanItaly
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Summers MP, Parmigiani JP. The dynamic shear moduli of whale blubber. Biorheology 2015; 51:399-408. [PMID: 25813836 DOI: 10.3233/bir-14036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Blubber is a thick adipose tissue located beneath the dermas. Its viscoelastic properties affect whale tracking tag design, hydrodynamics, and acoustical properties that can be used to study animal behavior and avoid ship strikes. OBJECTIVE Measure the dynamic shear storage and loss moduli for whale blubber at distances below the dermas for several species. Also, measure the non-collagen and collagen protein content to explore a correlation to viscoelastic properties. METHODS Blubber samples were obtained from whale strandings (humpback, sperm, and two gray) in the Pacific Northwest. Shear moduli were measured at oscillation frequencies of 0.31 Hz to 25 Hz using a rotational rheometer. Protein content was measured using a staining protocol. RESULTS Storage modulus and loss modulus variation with frequency was very consistent across all samples tested. Log-linear and extended polynomials respectively had R-squared values of at least 0.96. Variation of both moduli with depth was fit reasonably well by fourth-order polynomials. Protein content trends varied with species. CONCLUSIONS The samples used in this study were necrotic tissue, however the variation with frequency and to a lesser extent depth was very consistent and may have a broader applicability. Protein content was not found to correlate to moduli values.
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Abstract
Respirable dust is of particular concern in the construction industry because it contains crystalline silica. Respirable forms of silica are a severe health threat because they heighten the risk of numerous respirable diseases. Concrete cutting, a common work practice in the construction industry, is a major contributor to dust generation. No studies have been found that focus on the dust suppression of concrete-cutting chainsaws, presumably because, during normal operation water is supplied continuously and copiously to the dust generation points. However, there is a desire to better understand dust creation at low water flow rates. In this case study, a water-soluble surfactant additive was used in the chainsaw's water supply. Cutting was performed on a free-standing concrete wall in a covered outdoor lab with a hand-held, gas-powered, concrete-cutting chainsaw. Air was sampled at the operator's lapel, and around the concrete wall to simulate nearby personnel. Two additive concentrations were tested (2.0% and 0.2%), across a range of fluid flow rates (0.38-3.8 Lpm [0.1-1.0 gpm] at 0.38 Lpm [0.1 gpm] increments). Results indicate that when a lower concentration of additive is used exposure levels increase. However, all exposure levels, once adjusted for 3 hours of continuous cutting in an 8-hour work shift, are below the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 5 mg/m(3). Estimates were made using trend lines to predict the fluid flow rates that would cause respirable dust exposure to exceed both the OSHA PEL and the American Conference of Governmental Industrial Hygienists (ACGIH®) threshold limit value (TLV).
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Affiliation(s)
- Michael P Summers
- a Mechanical, Industrial, and Manufacturing Engineering Department , Oregon State University , Corvallis , Oregon
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Affiliation(s)
- E C Lipman
- Department of Pharmaceutics, The School of Pharmacy, University of London, 29–39 Brunswick Square, London, WC1N 1AX
| | - M P Summers
- Department of Pharmaceutics, The School of Pharmacy, University of London, 29–39 Brunswick Square, London, WC1N 1AX
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Tuladhar MD, Carless JE, Summers MP. The Effect of Particle Size, Compression Pressure and Crystal Form on the Dissolution Rate of Disintegrated Tablets of Phenylbutazone. J Pharm Pharmacol 2011. [DOI: 10.1111/j.2042-7158.1981.tb11682.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- MD Tuladhar
- Dept. of Pharmaceutics, The School of Pharmacy, University of London, London WC1N 1AX
| | - JE Carless
- Dept. of Pharmaceutics, The School of Pharmacy, University of London, London WC1N 1AX
| | - MP Summers
- Dept. of Pharmaceutics, The School of Pharmacy, University of London, London WC1N 1AX
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Tainsh DA, Summers MP. Strain Gauge Signal Modification Using the Diosna-Boots Granulation End Point Control System and its Relevance to Scale up Problems. J Pharm Pharmacol 2011. [DOI: 10.1111/j.2042-7158.1982.tb00878.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D A Tainsh
- Dept. of Pharmaceutics, The School of Pharmacy, University of London, London WC1N 1AX
| | - M P Summers
- Dept. of Pharmaceutics, The School of Pharmacy, University of London, London WC1N 1AX
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Cook GD, Summers MP. Stress Relaxation of Compressed Single and Multicomponent Systems. J Pharm Pharmacol 2011. [DOI: 10.1111/j.2042-7158.1986.tb14305.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- G D Cook
- Department of Pharmaceutics, School of Pharmacy, 29/39 Brunswick Square, London. WC1N 1AX
| | - M P Summers
- Department of Pharmaceutics, School of Pharmacy, 29/39 Brunswick Square, London. WC1N 1AX
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Affiliation(s)
- G D Cook
- Dept. of Pharmaceutics, The School of Pharmacy, 29/39 Brunswick Square, London WC1N 1AX
| | - M P Summers
- Dept. of Pharmaceutics, The School of Pharmacy, 29/39 Brunswick Square, London WC1N 1AX
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Lafferty SV, Summers MP, Mackey R, Newton JM. The Application of Dynamic Mechanical Thermal Analysis to Study the Physical Properties of Free Polymeric Films. J Pharm Pharmacol 2011. [DOI: 10.1111/j.2042-7158.1990.tb14398.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - MP Summers
- School of Pharmacy, University of London
| | - R Mackey
- The Wellcome Foundation, Dartford, Kent
| | - J M Newton
- School of Pharmacy, University of London
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Abstract
Mixtures of aspirin with sodium chloride, sucrose, Starch 1500 or Emcompress have been compressed to two maximum upper punch pressures at two compression speeds. Non-linear relationships between tensile strength and composition, and tablet porosity and composition were found in all cases. Tablets of the individual materials compressed at fast speed showed either little change or a reduction in tensile strength when compared with those compressed at slow speed. For mixtures of aspirin with Starch 1500, tablets compressed at fast speed were weaker and more porous than those compressed at slow speed. However, some mixtures of aspirin with sodium chloride, sucrose or Emcompress gave tablets with greater tensile strength and lower porosity when prepared at fast compression speed compared with tablets prepared at slow speed. This behaviour was attributed to the modification of the consolidation behaviour of the aspirin by the second material.
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Affiliation(s)
- G D Cook
- School of Pharmacy, University of London, UK
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Abstract
A high resolution electron microscopy study was undertaken on samples of sulphathiazole obtained by recrystallization at 0 degrees C, 30 degrees C and 70 degrees C. Low magnification electron microscopy study of the crystals showed featureless morphology yet the resolved lattice images showed imperfections such as dislocations, lattice irregularities and regions of discontinuity.
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Affiliation(s)
- Z H Luklinska
- Materials Department, Queen Mary College, University of London
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Abstract
The influence of size, configuration and positioning of die wall strain gauges on the measurement of radially transmitted stress developed during tableting was investigated. Calibration of strain gauges attached to a cutaway die wall was achieved by compression of rubber-like materials in the die, Breon Polyblend 504 being more effective than red rubber for this purpose. Hysteresis of response observed when calibrating a thin-walled die was possible due to excessive distortion of the weakened die wall although the extent of this hysteresis varied with calibration material. The use of full bridge arrangements produced an increase in response when the compression site was moved away from the gauges. The opposite effect was seen when half bridge arrangements, using two active gauges, were used. The paradoxical effect observed when full bridge arrangements were used was shown to be due to straining of the compensating gauges. The dependence of die wall response on compact position was substantially reduced by the use of multiple gauges mounted along the die length and connected together to form a single gauge on each side of the die.
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Tuladhar MD, Carless JE, Summers MP. The effects of polymorphism, particle size and compression pressure on the dissolution rate of phenylbutazone tablets. J Pharm Pharmacol 1983; 35:269-74. [PMID: 6134792 DOI: 10.1111/j.2042-7158.1983.tb02932.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The dissolution rate of phenylbutazone from tablets after disintegration has been used to determine whether the drug particles underwent crushing or bonding during compression. Two polymorphic forms of the drug were used and the predominant effect for high drug concentration (60%), during compression was dependent upon the original particle size of the drug and its polymorphic form. With a low drug concentration (10%) in the tablet, the diluent protected the drug particles from bonding together. The particle size change of the drug during compression was affected by the nature of the diluent present. Lactose had an abrasive action on Form A phenylbutazone compared with Avicel but had little effect on the more ductile Form B. When the contact time of compression was decreased from 29 to 0.26 s, the 6 microns particles of drug showed less bonding at the shorter time (faster rate of compression) but the effect observed with the larger particles was independent the compression rate.
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Abstract
Five different polymorphic forms of phenylbutazone were prepared and characterized by differential scanning calorimetry (D.S.C.). Rapid heating rates produced single endothermic peaks due to melting but slower heating rates resulted in interconversion of three of the polymorphs to the more stable form. Interconversion on grinding the polymorphs was also observed. From equilibrium solubility and intrinsic dissolution rates it was concluded that the dissolution process could be described by the Berthoud model. The effect of some tablet excipients on the dissolution process is briefly reported.
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Abstract
Glasses were prepared from a number of barbiturates. The viscosities and glass transition temperatures of the glasses were dependent on the structure of the groups present on the C-5 and N-1 atoms. Solid dispersions were prepared from three selected barbiturates formulated with citric acid. The glass transition temperatures of these systems indicated that a 1:1 molar ratio complex was formed between the two components and that intermolecular bonding was stronger in the complex than in the individual components.
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Abstract
The tensile strengths of compacts of different crystal forms of aspirin, sulfathiazole, and barbital were determined with a modified tablet hardness tester. For each material, the tensile strength could be correlated with the amount of plastic flow and/or crushing undergone by each crystal form during compression.
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Summers MP, Enever RP. Effect of primidone concentration on glass transition temperature and dissolution of solid dispersion systems containing primidone and citric acid. J Pharm Sci 1977; 66:825-8. [PMID: 874784 DOI: 10.1002/jps.2600660622] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The glass transition temperatures of glasses containing various concentrations of primidone in citric acid were measured and found to increase as the primidone concentration increased. Dissolution studies of these systems and particle-size measurements of primidone precipitated during dissolution of devitrified glasses suggest that the increase in the dissolution rate of the devitrified systems is due to both the small size of the precipitated crystals and the excellent wettability of these systems.
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Abstract
Solid dispersions containing 1--32% (w/w) primidone were prepared by fusing the drug with citric acid and rapidly cooling the melt. The solidified dispersions were clear glasses which devitrified on aging or when stored at 60 degrees for up to 3 days. The phase diagram of the devitrified system indicated that the drug may exist as a solid solution at 1--3% (w/w) concentrations but that a eutectic mixture is formed at higher concentrations. The solubility of primidone increased in the presence of citric acid. Preliminary dissolution studies showed that the dissolution rate from the solid dispersion was greater than that of the pure drug or the physical mixture.
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Summers MP, Enever RP, Carless JE. The influence of crystal form on the radial stress transmission characteristics of pharmaceutical materials. J Pharm Pharmacol 1976; 28:89-99. [PMID: 6687 DOI: 10.1111/j.2042-7158.1976.tb04105.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Various crystal forms of sulphathiazole, barbitone and aspirin were compressed in a single-punch tablet machine instrumented to monitor axially applied and radially transmitted forces, and upper punch movement. The changes in radial stress during the compression cycle depended upon the polymorphic form of the compressed material. The results were rationalized in terms of the degree of plastic flow/crushing that occurred with each material, and the degree to which the final compact underwent elastic compression. It is postulated that the reduction in the transition temperature of polymorphic forms of sulphathiazole and barbitone and the polymorphic transition of sulphathiazole Form II was due to the production of dislocations in the crystal and the crystals at crystal boundaries formed in the compressed materials.
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