Thermodynamically stable amorphous drug dispersions in amorphous hydrophilic polymers engineered by hot melt extrusion.

In this study thermodynamically stable dispersions of amorphous quinine, a model BCS class 2 therapeutic agent, within an amorphous polymeric platform (HPC), termed a solid-in-solid dispersion, were produced using hot melt extrusion. Characterisation of the pre-extrudates and extrudates was performed using hyper-differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and Raman spectroscopy. Water uptake by the raw materials was determined using dynamic vapour sorption (DVS) analysis. Furthermore, the presence or absence of crystalline drug following storage at 25 °C/60% relative humidity and 40 °C/75% relative humidity in a sealed glass jar, and at 40 °C/75% relative humidity in an open glass jar for 3 months was determined using PXRD. Amorphous quinine was generated in situ during extrusion from both quinine base (5%, 10%, 20% w/w drug loading) and from quinine hydrochloride (5%, 10% w/w drug loading) and remained thermodynamically stable as a solid-in-solid dispersion within the HPC extrudates. When processed with HPC, quinine hydrochloride (20% w/w) was converted to amorphous quinine hydrochloride. Whilst stable for up to 3 months when stored under sealed conditions, this amorphous form was unstable, resulting in recrystallisation of the hydrochloride salt following storage for 1 month at 40 °C/75% relative humidity in an open glass jar. The behaviour of the amorphous quinine hydrochloride (20% w/w) HPC extrudate was related, at least in part, to the lower stability and the hygroscopic properties of this amorphous form.

Characterisation and modelling of the thermorheological properties of pharmaceutical polymers and their blends using capillary rheometry: Implications for hot melt processing of dosage forms.

Given the growing interest in thermal processing methods, this study describes the use of an advanced rheological technique, capillary rheometry, to accurately determine the thermorheological properties of two pharmaceutical polymers, Eudragit E100 (E100) and hydroxypropylcellulose JF (HPC) and their blends, both in the presence and absence of a model therapeutic agent (quinine, as the base and hydrochloride salt). Furthermore, the glass transition temperatures (Tg) of the cooled extrudates produced using capillary rheometry were characterised using Dynamic Mechanical Thermal Analysis (DMTA) thereby enabling correlations to be drawn between the information derived from capillary rheometry and the glass transition properties of the extrudates. The shear viscosities of E100 and HPC (and their blends) decreased as functions of increasing temperature and shear rates, with the shear viscosity of E100 being significantly greater than that of HPC at all temperatures and shear rates. All platforms were readily processed at shear rates relevant to extrusion (approximately 200–300 s−1) and injection moulding (approximately 900 s−1). Quinine base was observed to lower the shear viscosities of E100 and E100/HPC blends during processing and the Tg of extrudates, indicative of plasticisation at processing temperatures and when cooled (i.e. in the solid state). Quinine hydrochloride (20% w/w) increased the shear viscosities of E100 and HPC and their blends during processing and did not affect the Tg of the parent polymer. However, the shear viscosities of these systems were not prohibitive to processing at shear rates relevant to extrusion and injection moulding. As the ratio of E100:HPC increased within the polymer blends the effects of quinine base on the lowering of both shear viscosity and Tg of the polymer blends increased, reflecting the greater solubility of quinine within E100. In conclusion, this study has highlighted the importance of capillary rheometry in identifying processing conditions, polymer miscibility and plasticisation phenomena.

Quality of reporting of dental survival analyses

To explore the quality of reporting (writing and graphics) of articles that used time-to-event analyses to report dental treatment outcomes. A systematic search of the top 50 dental journals in 2008 produced the sample of articles for this analysis. Articles reporting treatment outcomes with (n = 95) and without (n = 91) time-to-event statistics were reviewed. Survival descriptive words used in the two groups were analysed (Pearson's chi-square). The quality of life tables, survival curves and time-to-event statistics were assessed (Kappa analysed agreement) and explored. Words describing dental outcomes 'over time' were more common in time-to-event compared with control articles (77%, 3%, P < 0.001). Non-specific use of 'rate' was common across both groups. Life tables and survival curves were used by 39% and 48% of the time-to-event articles, with at least one used by 82%. Construction quality was poor: 21% of life tables and 28% of survival curves achieved an acceptable standard. Time-to-event statistical reporting was poor: 3% achieved a high and 59% achieved an acceptable standard. The survival statistic, summary figure and standard error were reported in 76%, 95% and 20% of time-to-event articles. Individual statistical terms and graphic aids were common within and unique to time-to-event articles. Unfortunately, important details were regularly omitted from statistical descriptions and survival figures making the overall quality poor. It is likely this will mean such articles will be incorrectly indexed in databases, missed by searchers and unable to be understood completely if identified.

Accuracy of medical subject heading indexing of dental survival analyses

PURPOSE: To assess the Medical Subject Headings (MeSH) indexing of articles that employed time-to-event analyses to report outcomes of dental treatment in patients.

MATERIALS AND METHODS: Articles published in 2008 in 50 dental journals with the highest impact factors were hand searched to identify articles reporting dental treatment outcomes over time in human subjects with time-to-event statistics (included, n = 95), without time-to-event statistics (active controls, n = 91), and all other articles (passive controls, n = 6,769). The search was systematic (kappa 0.92 for screening, 0.86 for eligibility). Outcome-, statistic- and time-related MeSH were identified, and differences in allocation between groups were analyzed with chi-square and Fischer exact statistics.

RESULTS: The most frequently allocated MeSH for included and active control articles were "dental restoration failure" (77% and 52%, respectively) and "treatment outcome" (54% and 48%, respectively). Outcome MeSH was similar between these groups (86% and 77%, respectively) and significantly greater than passive controls (10%, P < .001). Significantly more statistical MeSH were allocated to the included articles than to the active or passive controls (67%, 15%, and 1%, respectively, P < .001). Sixty-nine included articles specifically used Kaplan-Meier or life table analyses, but only 42% (n = 29) were indexed as such. Significantly more time-related MeSH were allocated to the included than the active controls (92% and 79%, respectively, P = .02), or to the passive controls (22%, P < .001).

CONCLUSIONS: MeSH allocation within MEDLINE to time-to-event dental articles was inaccurate and inconsistent. Statistical MeSH were omitted from 30% of the included articles and incorrectly allocated to 15% of active controls. Such errors adversely impact search accuracy.

Will your article be found? Authors choose a confusing variety of words to describe dental survival analyses

OBJECTIVES: Identify the words and phrases that authors used to describe time-to-event outcomes of dental treatments in patients.

MATERIALS AND METHODS: A systematic handsearch of 50 dental journals with the highest Citation Index for 2008 identified articles reporting dental treatment with time-to-event statistics (included "case" articles, n = 95), without time-to-event statistics (active "control" articles, n = 91), and all other articles (passive "control" articles n = 6796). The included and active controls were read, identifying 43 English words across the title, aim and abstract, indicating that outcomes were studied over time. Once identified, these words were sought within the 6796 passive controls. Words were divided into six groups. Differences in use of words were analyzed with Pearson's chi-square across these six groups, and the three locations (title, aim, and abstract).

RESULTS: In the abstracts, included articles used group 1 (statistical technique) and group 2 (statistical terms) more frequently than the active and passive controls (group 1: 35%, 2%, 0.37%, P < 0.001 and group 2: 31%, 1%, 0.06%, P < 0.001). The included and active controls used group 3 (quasi-statistical) equally, but significantly more often than the passive controls (82%, 78%, 3.21%, P < 0.001). In the aims, use of target words was similar for included and active controls, but less frequent for groups 1-4 in the passive controls (P < 0.001). In the title, group 2 (statistical techniques) and groups 3-5 (outcomes) were similar for included and active controls, but groups 2 and 3 were less frequent in the passive controls (P < 0.001). Significantly more included articles used group 6 words (stating the study duration) (54%, 30%, P = 0.001).

CONCLUSION: All included articles used time-to-event analyses, but two-thirds did not include words to highlight this in the abstract. There is great variation in the words authors used to describe dental time-to-event outcomes. Electronic identification of such articles would be inconsistent, with low sensitivity and specificity. Authors should improve the reporting quality. Journals should allow sufficient space in abstracts to summarize research, and not impose unrealistic word limits. Readers should be mindful of these problems when searching for relevant articles. Additional research is required in this field.

Moleculary imprinted polymers for extraction of components from foodstruffs

The present invention relates to a novel class of water compatible molecularly imprinted polymers (AquaMIPs) capable of selectively binding target molecules such as riboflavin, or analogues thereof, in water or aqueous media, their synthesis and use thereof in food processing and extraction or separation processes.

Stoichiometric Molecularly Imprinted Polymers for the Recognition of Anti-Cancer Pro-drug Tegafur

Molecularly Imprinted Polymers (MIPs) targeting tegafur, an anti-cancer 5-fluorouracil pro-drug, have been prepared by stoichiometric imprinting using 2,6-bis(acrylamido)pyridine (BAAPy) as the functional monomer. Solution association between tegafur and BAAPy was studied by 1H NMR titration, which confirmed the formation of 1:1 complexes with an affinity constant of 574±15 M-1 ¬in CDCl3. Evaluation of the synthesised materials by HPLC and equilibrium rebinding experiments revealed high selectivity of the imprinted polymer for the pro-drug versus 5-fluorouracil and other competing analytes, with maximum imprinting factors of 25.3 and a binding capacity of 45.1 μmol g-1. The synthesised imprinted polymer was employed in solid-phase extraction of the pro-drug using an optimised protocol that included a simple wash with the porogen used in the preparation of the material. Tegafur recoveries of up to 96% were achieved from aqueous samples and 92% from urine samples spiked with the template and three competing analytes. The results demonstrate the potential of the prepared polymers in the pre-concentration of tegafur from biological samples, which could be an invaluable tool in the monitoring of patient compliance and drug uptake and excretion.

Pre-Radiotherapy Dental Assessment of Head and Neck Oncology Patients: An Audit.

Objectives: Approximately 300 people are diagnosed with Head and Neck cancer annually in Northern Ireland. The management may include treatment by surgery or by chemotherapy and radiotherapy,
or a combination of modalities. Patients whose oral cavity, teeth, salivary glands and jaws that
will be affected by treatment, particularly radiotherapy should have a pre-treatment assessment. This should be done as early as possible to maximise the time available for dental management. However, this can be challenging owing to the complexities of cancer diagnosis, treatment planning and multidisciplinary management. At the Belfast Dental Hospital, a number of patients were referred post- radiotherapy with complications after not having received a pre-treatment assessment. The referrals for pre- treatment dental assessment were also late in patients’ multidisciplinary journey, limiting the time period
for dental input. The purpose of this audit was to examine the time period between dental assessment and commencement of radiotherapy and whether this was an adequate time frame for dental management. This audit will also examine the dental diseases present and the treatments required pre-radiotherapy. Methods: Data for this audit was collected over 4 months in 2012
by analysing the dental charts and referrals of new patients who were referred to and attended the dental head and neck oncology clinic. A standardised referral pro-forma was introduced from September 2013 to improve the referral process.
A re-audit was conducted over 4 months in 2014. Data was collected similarly as previous. The time period between dental assessment and commencement of radiotherapy was examined. The presence of dental disease and subsequent treatments required were also noted.
Results: 63 new patients were examined in the dental head and neck oncology clinic over 4 months in 2012. 48 (76.2%) were examined pre-radiotherapy. The average length of time between dental assessment and radiotherapy commencement was 11 days. A new standardised referral pro-forma was introduced in 2013. In the re-audit, 65 new patients were seen over 4 months in 2014.
60 (92.3%) patients were examined pre-radiotherapy. The average length of time between dental assessment and radiotherapy commencement was 18 days.
Conclusion: Given the high prevalence of pre-existing dental disease amongst head and neck cancer patients, prompt dental assessment and treatment is vital. Efforts aimed at improving the care pathway are on-going through the implementation of a mandatory referral pro-forma and a dedicated assessment clinic.

Comparison of Composite Placement Techniques by Recently Qualified Dental Practitioners.

Objectives: To evaluate the placement of composite materials by new graduates using three alternative placement techniques.Methods: A cohort of 34 recently qualified graduates were asked to restore class II interproximal cavities in plastic teeth using three different techniques.

(i) A conventional incremental filling technique (Herculite XRV) using increments no larger than 2-mm with an initial layer on the cervical floor of the box of 1-mm.
(ii) Flowable bulk fill technique (Dentsply SDR) bulk fill placement in a 3-mm layer followed by an incremental fill of a microhybrid resin
(iii) Bulk fill (Kerr Sonicfill) which involved restorations placed in a 5-mm layer.

The operators were instructed in each technique, didactically and with a hands-on demonstration, prior to restoration placement.
All restorations were cured according to manufacturer’s recommendations. Each participant restored 3 teeth, 1 tooth per treatment technique.
The restorations were evaluated using modified USPHS criteria to assess both the marginal adaptation and the surface texture of the restorations. Blind evaluations were carried out independently by two examiners with the aid of magnification (loupes X2.5). Examiners were standardized prior to evaluation.
Results: Gaps between the tooth margins and the restoration or between the layers of the restoration were found in 13 of Group (i), 3 of Group (ii), and 4 of Group (iii)
Statistical analysis revealed a significant difference between the incrementally filled group (i) and the flowable bulk-fill group (ii) (p=0.0043) and between the incrementally filled (i) and the bulk fill groups (iii) (p=0.012) and no statistical difference (p=0.69) between the bulk filled groups Conclusions: Bulk fill techniques may result in a more satisfactory seal of the cavity margins when restoring with composite.

Identification of novel Factor XI mutations in a patient requiring dental extractions

Factor XI is a serine protease that participates in the intrinsic pathway of blood coagulation. Patients deficient in factor XI exhibit varying degrees of post operative bleeding following invasive surgical procedures such as dental extractions. Objectives: The aim of the study was to identify the specific mutations in a patient from a family with known factor XI deficiency. Methods: Samples were obtained from the patient, his mother and his father and subjected to DNA sequencing. Each protein coding exon 2-15 of the factor XI gene was amplified by polymerase chain reaction (PCR) followed by bidirectional sequencing utilizing di-deoxy chain termination chemistry. Results: The patient had a factor XI level of 20% of normal. Initial sequencing of factor XI from the patient identified a point mutation (646G>A) and a putative splice site mutation (1567+4A>T) in intron 13. These are novel previously unreported mutations. DNA sequence analysis of the mother revealed the 1567+4A>T mutation and the father exhibited the 646G>A mutation. As a consequence the treatment proceeded without serious bleeding complication and required administration only of transexamic acid though factor XI was available as haemostatic cover. Conclusion: The two mutations identified in this family are novel; further laboratory investigation of the functional consequences of those mutations is currently underway. Although factor XI deficiency is rare in the Northern Irish population this study highlights the techniques available to sequence and analyse this and similar haematological disorders.

Impact of Referral Protocols on the Dental Management of Patients Undergoing Treatment for Head and Neck Oncology in Northern Ireland

Objective: To evaluate the handling, by a group of practice-based researchers, of a recently introduced bulk fill resin-based composite restorative material, Filtek Bulk Fill Restorative (3M ESPE).

Methods: The twelve selected evaluators were sent explanatory letters, a pack of the material under investigation to use for 8 weeks, and a questionnaire.

Results: The evaluators rated the ease of use of the bulk fill restorative the same as the previously used posterior composite material. The provision of one shade only for evaluation may have compromised the score for aesthetic quality. No post-operative sensitivity was reported.

Conclusions: The bulk fill material was well received as indicated by the high number of evaluators who would both purchase the material and recommend it to colleagues.

Clinical relevance: A recently introduced bulk fill restorative material achieved a rating for handling which was similar to the evaluators’ previously used resin composite, although there were some concerns regarding the translucency of the material.

NPY Y1 and VPAC1 receptor expression in human dental pulps

Neuropeptides such as neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) have been shown by our research group to be present in human dental pulp tissue. Neuropeptides cannot cross cell membranes and therefore to exert their biological effects they must bind to selected receptors on the surface of target cell membranes. However, the expression of receptor proteins for NPY and/or VIP have yet to be reported in human pulp tissue. The presence of neuropeptide receptors can be conveniently determined by Western blotting using specific anti-receptor antibodies. Objectives: The aim of this work was to identify the presence of the NPY Y1 receptor and the VIP receptor VPAC1 in human dental pulp tissue from both intact and carious teeth using Western blotting. Methods: Pulp tissue was collected from both intact and carious teeth and membrane preparations from these tissues were then subject to sodium dodecyl sulphate gel electrophoresis (SDS-PAGE), transferred to nitrocellulose and probed with specific antibodies to either the NPY Y1 receptor or the VPAC1 receptor. Results: Individual Western blotting experiments revealed the presence of immunoreactive bands corresponding to the known molecular weights of the NPY Y1 and VPAC1 receptor proteins in both intact and carious pulp samples. Conclusions: Demonstration of the presence of NPY Y1 and VPAC1 receptor protein expression in pulpal tissue from intact and carious teeth provides further support for the roles of these neuropeptides in pulpal health and disease.

TRP Channels and calcium signalling in dental pulp stem cells

Introduction: Ca2+ ion is an important intracellular messenger essential for the regulation of various cellular functions including proliferation, differentiation and apoptosis. Transient Receptor Potential (TRP) channels are calcium permeable cationic channels that play important role in regulation of free intracellular calcium ([Ca2+]i) in response to thermal, physical and chemical stimuli. Ca2+ signalling in human dental pulp stem cells (hDPSCs) and the ion channels regulating Ca2+ are largely not known. Objectives: Investigate changes in [Ca2+]i and determine the ion channels that regulate calcium signalling in hDPSCs. Methods: DPSCs were derived from immature third molars and cells less than passage 6 were used in all the experiments. Changes in [Ca2+]i were studied with Fura2 calcium imaging. RNA was extracted from DPSCs and a panel of TRP channel gene expression was determined by qPCR employing custom designed FAM TRP specific primers and probes (Roche, UK) and the Light Cycler 480 Probes Master (Roche). Results: hDPSCs express gene transcripts for all TRP families including TRPV1, V2, V4, TRPA1, TRPC3, TRPC5, TRPC6, TRPM3, TRPM7 and TRPP2. Stimulation of cells with appropriate TRP channel agonist induced increase in [Ca2+]i and similar responses were obtained when cell were mechanically stimulated by membrane stretch with application of hypotonic solution. Conclusion: TRP channels mediate calcium signalling in hDPSCs that merit further investigation.

Osteoprotegerin Expression in the Dental Pulp

Objectives: The inflammatory response to pulpal injury or infection has major clinical significance. Osteoprotegerin (OPG) is a soluble decoy receptor for Receptor Activator of NF kappa B Ligand (RANKL), preventing ligand binding to its receptor (RANK), thus inhibiting clastic cell formation. The aim of the study is to investigate the expression of OPG in human dental pulp and the effects of inflammatory mediators. This study will specifically investigate the effects of Transforming Growth Factor Beta-1 (TGF-β1) and Interleukin 1-Beta (IL-1β) on the expression of OPG on pulp fibroblasts in vitro. Method: Five primary pulp fibroblast populations were obtained by explant culture of healthy pulp tissue. Triplicate cultures were grown to confluence in 12-well plates and stimulated for 48 hours with IL-1β (10ng/ml) or TGF-β1 (10ng/ml). The conditioned media was collected and OPG levels detected by ELISA (R+D Systems, UK). Results: All fibroblast populations produced quantifiable levels of OPG in a time-dependant fashion. IL-1β significantly increased the expression of OPG (p<0.05) in all cultures. In contrast, TGF-β1 had no significant effect on OPG expression levels. In addition, previous work in our laboratory demonstrated both TGF-β1 and IL-1β stimulated OPG expression by periodontal ligament fibroblasts. Conclusion: These data indicate that IL-1β-regulated expression of OPG by pulpal fibroblasts may mediate hard tissue turnover in the inflamed dental pulp.