Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 31
Filter
Add more filters

Country/Region as subject
Publication year range
1.
Hum Mol Genet ; 27(4): 742-756, 2018 02 15.
Article in English | MEDLINE | ID: mdl-29309628

ABSTRACT

Genome-wide association studies of birth weight have focused on fetal genetics, whereas relatively little is known about the role of maternal genetic variation. We aimed to identify maternal genetic variants associated with birth weight that could highlight potentially relevant maternal determinants of fetal growth. We meta-analysed data on up to 8.7 million SNPs in up to 86 577 women of European descent from the Early Growth Genetics (EGG) Consortium and the UK Biobank. We used structural equation modelling (SEM) and analyses of mother-child pairs to quantify the separate maternal and fetal genetic effects. Maternal SNPs at 10 loci (MTNR1B, HMGA2, SH2B3, KCNAB1, L3MBTL3, GCK, EBF1, TCF7L2, ACTL9, CYP3A7) were associated with offspring birth weight at P < 5 × 10-8. In SEM analyses, at least 7 of the 10 associations were consistent with effects of the maternal genotype acting via the intrauterine environment, rather than via effects of shared alleles with the fetus. Variants, or correlated proxies, at many of the loci had been previously associated with adult traits, including fasting glucose (MTNR1B, GCK and TCF7L2) and sex hormone levels (CYP3A7), and one (EBF1) with gestational duration. The identified associations indicate that genetic effects on maternal glucose, cytochrome P450 activity and gestational duration, and potentially on maternal blood pressure and immune function, are relevant for fetal growth. Further characterization of these associations in mechanistic and causal analyses will enhance understanding of the potentially modifiable maternal determinants of fetal growth, with the goal of reducing the morbidity and mortality associated with low and high birth weights.


Subject(s)
Birth Weight/genetics , Genome-Wide Association Study/methods , Polymorphism, Single Nucleotide/genetics , Actins/genetics , Adaptor Proteins, Signal Transducing , Alleles , Birth Weight/physiology , Cytochrome P-450 CYP3A/genetics , DNA-Binding Proteins/genetics , Female , Genetic Variation/genetics , Genotype , Germinal Center Kinases , Gestational Age , HMGA2 Protein/genetics , Humans , Intracellular Signaling Peptides and Proteins , Kv1.3 Potassium Channel/genetics , Protein Serine-Threonine Kinases/genetics , Proteins/genetics , Receptor, Melatonin, MT2/genetics , Trans-Activators/genetics , Transcription Factor 7-Like 2 Protein/genetics
2.
Mol Pharm ; 15(11): 5327-5335, 2018 11 05.
Article in English | MEDLINE | ID: mdl-30259745

ABSTRACT

The Flory-Huggins (F-H) solubility equation has been widely used to describe the solubility of a small-molecule drug in a polymeric carrier and thus determine the design space available for formulating a stable amorphous solid dispersion. The F-H interaction parameter (χ) describes the thermodynamic properties of drug-polymer solutions and accounts for any enthalpic and entropic changes in solubility. Many studies have found that for a limited compositional range, χ varies proportionally to the inverse of the melting temperature of the drug. We explored this relationship using a highly sensitive DSC technique to detect remaining residual crystalline active pharmaceutical ingredients (APIs) following annealing of ball milled mixtures of crystalline itraconazole (ITZ) and either Soluplus or hydroxypropyl methylcellulose phthalate (HPMCP) at temperatures near the estimated solubility curve. Depending on the experimental approach taken, the measurement of drug-polymer solubility can be restricted to mixtures with a high proportion of drug, but in this study, solubility was experimentally determined for mixtures with API content as low as 10 wt %. Results suggest that the proposed linear relationship does not extend to compositions with smaller amounts of API, instead indicating that χ was both temperature- and composition-dependent for the systems studied. The feasibility of this technique to measure interactions in a ternary system containing itraconazole and both polymers was also determined; ITZ-HPMCP exhibited the most favorable values of χ, while ITZ-Soluplus and ITZ-Soluplus-HPMCP demonstrated similar interaction parameters.


Subject(s)
Chemistry, Pharmaceutical/methods , Drug Compounding/methods , Pharmaceutical Preparations/chemistry , Polymers/chemistry , Temperature , Calorimetry, Differential Scanning/methods , Crystallization , Feasibility Studies , Solubility
3.
Mol Pharm ; 12(5): 1377-90, 2015 May 04.
Article in English | MEDLINE | ID: mdl-25730138

ABSTRACT

The formulation of BCS Class II drugs as amorphous solid dispersions has been shown to provide advantages with respect to improving the aqueous solubility of these compounds. While hot melt extrusion (HME) and spray drying (SD) are among the most common methods for the production of amorphous solid dispersions (ASDs), the high temperatures often required for HME can restrict the processing of thermally labile drugs, while the use of toxic organic solvents during SD can impact on end-product toxicity. In this study, we investigated the potential of supercritical fluid impregnation (SFI) using carbon dioxide as an alternative process for ASD production of a model poorly water-soluble drug, indomethacin (INM). In doing so, we produced ASDs without the use of organic solvents and at temperatures considerably lower than those required for HME. Previous studies have concentrated on the characterization of ASDs produced using HME or SFI but have not considered both processes together. Dispersions were manufactured using two different polymers, Soluplus and polyvinylpyrrolidone K15 using both SFI and HME and characterized for drug morphology, homogeneity, presence of drug-polymer interactions, glass transition temperature, amorphous stability of the drug within the formulation, and nonsink drug release to measure the ability of each formulation to create a supersaturated drug solution. Fully amorphous dispersions were successfully produced at 50% w/w drug loading using HME and 30% w/w drug loading using SFI. For both polymers, formulations containing 50% w/w INM, manufactured via SFI, contained the drug in the γ-crystalline form. Interestingly, there were lower levels of crystallinity in PVP dispersions relative to SOL. FTIR was used to probe for the presence of drug-polymer interactions within both polymer systems. For PVP systems, the nature of these interactions depended upon processing method; however, for Soluplus formulations this was not the case. The area under the dissolution curve (AUC) was used as a measure of the time during which a supersaturated concentration could be maintained, and for all systems, SFI formulations performed better than similar HME formulations.


Subject(s)
Carbon Dioxide/chemistry , Chemistry, Pharmaceutical/methods , Polymers/chemistry , Drug Compounding , Indomethacin/chemistry , Polyethylene Glycols/chemistry , Polyvinyls/chemistry , Povidone/chemistry , Solubility , Spectroscopy, Fourier Transform Infrared
4.
Pharm Res ; 32(1): 167-79, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25074468

ABSTRACT

PURPOSE: Amorphous drug-polymer solid dispersions have been found to result in improved drug dissolution rates when compared to their crystalline counterparts. However, when the drug exists in the amorphous form it will possess a higher Gibb's free energy than its associated crystalline state and can recrystallize. Drug-polymer phase diagrams constructed through the application of the Flory Huggins (F-H) theory contain a wealth of information regarding thermodynamic and kinetic stability of the amorphous drug-polymer system. This study was aimed to evaluate the effects of various experimental conditions on the solubility and miscibility detections of drug-polymer binary system. METHODS: Felodipine (FD)-Polyvinylpyrrolidone (PVP) K15 (PVPK15) and FD-Polyvinylpyrrolidone/vinyl acetate (PVP/VA64) were the selected systems for this research. Physical mixtures with different drug loadings were mixed and ball milled. These samples were then processed using Differential Scanning Calorimetry (DSC) and measurements of melting point (Tend) and glass transition (Tg) were detected using heating rates of 0.5, 1.0 and 5.0°C/min. RESULTS: The melting point depression data was then used to calculate the F-H interaction parameter (χ) and extrapolated to lower temperatures to complete the liquid-solid transition curves. The theoretical binodal and spinodal curves were also constructed which were used to identify regions within the phase diagram. The effects of polymer selection, DSC heating rate, time above parent polymer Tg and polymer molecular weight were investigated by identifying amorphous drug miscibility limits at pharmaceutically relevant temperatures. CONCLUSION: The potential implications of these findings when applied to a non-ambient processing method such as Hot Melt Extrusion (HME) are also discussed.


Subject(s)
Chemistry, Pharmaceutical , Felodipine/chemistry , Phase Transition , Pyrrolidines/chemistry , Vinyl Compounds/chemistry , Calorimetry, Differential Scanning , Crystallization , Drug Stability , Kinetics , Molecular Weight , Thermodynamics , Transition Temperature
5.
Hum Mol Genet ; 21(24): 5344-58, 2012 Dec 15.
Article in English | MEDLINE | ID: mdl-22956269

ABSTRACT

Maternal smoking during pregnancy is associated with low birth weight. Common variation at rs1051730 is robustly associated with smoking quantity and was recently shown to influence smoking cessation during pregnancy, but its influence on birth weight is not clear. We aimed to investigate the association between this variant and birth weight of term, singleton offspring in a well-powered meta-analysis. We stratified 26 241 European origin study participants by smoking status (women who smoked during pregnancy versus women who did not smoke during pregnancy) and, in each stratum, analysed the association between maternal rs1051730 genotype and offspring birth weight. There was evidence of interaction between genotype and smoking (P = 0.007). In women who smoked during pregnancy, each additional smoking-related T-allele was associated with a 20 g [95% confidence interval (95% CI): 4-36 g] lower birth weight (P = 0.014). However, in women who did not smoke during pregnancy, the effect size estimate was 5 g per T-allele (95% CI: -4 to 14 g; P = 0.268). To conclude, smoking status during pregnancy modifies the association between maternal rs1051730 genotype and offspring birth weight. This strengthens the evidence that smoking during pregnancy is causally related to lower offspring birth weight and suggests that population interventions that effectively reduce smoking in pregnant women would result in a reduced prevalence of low birth weight.


Subject(s)
Birth Weight/genetics , Genetic Variation/genetics , Receptors, Nicotinic/genetics , Smoking/adverse effects , Female , Genetic Predisposition to Disease/genetics , Humans , Infant , Nerve Tissue Proteins/genetics , Pregnancy
6.
Arthritis Rheum ; 63(3): 645-53, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21061259

ABSTRACT

OBJECTIVE: Anti-tumor necrosis factor (anti-TNF) agents are successful therapies in rheumatoid arthritis (RA); however, inadequate response occurs in 30-40% of patients treated. Knowledge of the genetic factors that influence response may facilitate personalized therapy. The purpose of this study was to identify genetic predictors of response to anti-TNF therapy in RA and to validate our findings in independent cohorts. METHODS: Data from genome-wide association (GWA) studies were available from the Wellcome Trust Case Control Consortium for 566 anti-TNF-treated RA patients. Multivariate linear regression analysis of changes in the Disease Activity Score in 28 joints at 6 months was conducted at each single-nucleotide polymorphism (SNP) using an additive model. Associated markers (P < 10(-3) ) were genotyped in 2 independent replication cohorts (n = 379 and n = 341), and a combined analysis was performed. RESULTS: Of 171 successfully genotyped markers demonstrating association with treatment response in the GWA data, 7 were corroborated in the combined analysis. The strongest effect was at rs17301249, mapping to the EYA4 gene on chromosome 6: the minor allele conferred improved response to treatment (coefficient -0.27, P = 5.67(-05) ). The minor allele of rs1532269, mapping to the PDZD2 gene, was associated with a reduced treatment response (coefficient 0.20, P = 7.37(-04) ). The remaining associated SNPs mapped to intergenic regions on chromosomes 1, 4, 11, and 12. CONCLUSION: Using a genome-wide strategy, we have identified and validated the association of 7 genetic loci with response to anti-TNF treatment in RA. Additional confirmation of these findings in further cohorts will be required.


Subject(s)
Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/genetics , Genome-Wide Association Study , Precision Medicine/methods , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adaptor Proteins, Signal Transducing/genetics , Adult , Aged , Cell Adhesion Molecules , Cohort Studies , Female , Genetic Markers , Humans , Male , Middle Aged , Neoplasm Proteins/genetics , Polymorphism, Single Nucleotide/genetics , Predictive Value of Tests , Trans-Activators/genetics
7.
Front Psychol ; 13: 947507, 2022.
Article in English | MEDLINE | ID: mdl-36438307

ABSTRACT

To date, there are no brief child self-report coping measures for the pandemic and other major societal events resulting in social or learning disruptions for children. Ignoring the voice of children can ultimately result in programs or services that fail to meet their needs. Thus, a child self-report measure called the 3Cs (Children's Crisis Coping) was developed and underwent pilot evaluation. This measure was designed in collaboration with key stakeholders using a Knowledge Translation-Integrated development framework. Some of the primary concerns that were relevant in the literature for the development of a pandemic coping measure included stress, worries, loneliness, and unpredictable school changes. The completed 4-item measure, grounded in these concerns, demonstrated good internal consistency reliability, as well as convergent validity with mental health and meaning mindset. A Second Wave Positive Psychology framework is presented concerning a spiritual concept called "meaning mindset" and it's association with positive societal crisis coping (i.e., pandemic coping in the present study).

8.
Hum Mol Genet ; 17(22): 3532-8, 2008 Nov 15.
Article in English | MEDLINE | ID: mdl-18713756

ABSTRACT

Anti-tumour necrosis factor (TNF) agents have revolutionized the treatment of patients with rheumatoid arthritis (RA). These therapies are, however, expensive and 30% of patients fail to respond. In a large cohort of Caucasian RA patients treated with anti-TNF medications (total n = 1050, etanercept n = 455, infliximab n = 450), we investigated whether genotypes of eight single nucleotide polymorphisms in the region containing the TNF gene were associated with response to anti-TNF therapy. Linear regression analyses adjusted for baseline 28 joint disease activity score (DAS28), baseline health assessment questionnaire score, gender and concurrent disease modifying anti-rheumatic drug treatment were used to assess association of these polymorphisms with treatment response, defined by change in DAS28 after 6 months. Analyses were performed in the entire cohort, and also stratified by anti-TNF agent. Association between DAS28 response and TNF-308 (rs1800629) genotype (P = 0.001) was detected across the whole cohort. After stratification by anti-TNF agent, the rare TNF-308AA genotype was associated with a significantly poorer response compared with TNF-308GG in etanercept (P = 0.001, n = 7) but not infliximab (P = 0.8, n = 17) treated patients. Conversely, the GA genotype at TNF-238 (rs361525) was associated with a poorer response to infliximab (P = 0.028, n = 40), but not etanercept (P = 0.6, n = 33). Owing to the small numbers of patients in some of the genotype groups examined, our data must be regarded as preliminary and will require replication in further large cohorts of anti-TNF-treated patients. If confirmed, our findings suggest the potential for genotype at these markers to aid selection of anti-TNF agent in patients with RA.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/drug therapy , Immunoglobulin G/therapeutic use , Polymorphism, Single Nucleotide , Receptors, Tumor Necrosis Factor/therapeutic use , Tumor Necrosis Factor-alpha/genetics , Analysis of Variance , Cohort Studies , England , Etanercept , Female , Haplotypes , Humans , Infliximab , Linear Models , Male , Middle Aged , Surveys and Questionnaires , Tumor Necrosis Factor-alpha/metabolism
9.
Pharmacogenet Genomics ; 20(5): 338-41, 2010 May.
Article in English | MEDLINE | ID: mdl-20300049

ABSTRACT

The introduction of tumour necrosis factor antagonists (anti-TNF) has greatly improved the treatment of rheumatoid arthritis, however, a significant proportion of patients fail to respond to therapy. We hypothesized that variants spanning the type 2 TNF receptor (TNFR2) and the TNF cleavage enzyme (TACE) genes contribute towards the observed variation in patient response (defined as the absolute change in 28-joint count disease activity score). Twenty-nine single nucleotide polymorphisms (SNPs) were genotyped in a large cohort of patients (n=602) and analysed by multivariate linear regression. Three SNPs (rs520916, rs652625, rs597519) mapping upstream of TNFR2 showed borderline evidence for association (P<0.1) across the complete cohort and, more so, in the etanercept-treated subgroup. However, the evidence of association was neither replicated in an independent cohort (n=377) nor strengthened after combined analysis (n=979). We conclude that common SNPs spanning the TNFR2 and TNF cleavage enzyme (TACE) genes do not have a major effect on the response to anti-TNF therapy in rheumatoid arthritis patients.


Subject(s)
ADAM Proteins/genetics , Arthritis, Rheumatoid/genetics , Gene Expression Regulation , Polymorphism, Single Nucleotide , Receptors, Tumor Necrosis Factor, Type II/genetics , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Tumor Necrosis Factor-alpha/metabolism , ADAM17 Protein , Arthritis, Rheumatoid/drug therapy , Chromosome Mapping , Cohort Studies , Female , Humans , Male , Models, Genetic , Multivariate Analysis , Pharmacogenetics , Regression Analysis , Reproducibility of Results
10.
Ann Rheum Dis ; 69(6): 1029-35, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20444755

ABSTRACT

BACKGROUND: Anti-tumour necrosis factor (anti-TNF) therapy has proved to be highly successful in treating rheumatoid arthritis (RA), although 30-40% of patients have little or no response. The authors hypothesise that this may be genetically determined. In other complex diseases, susceptibility genes have been shown to influence treatment response. The aim of the current study was to investigate the association of markers within confirmed RA susceptibility loci with the response to anti-TNF treatment. METHODS: Eighteen single nucleotide polymorphisms (SNPs) mapping to 11 genetic loci were genotyped in 1012 patients with RA receiving treatment with etanercept, infliximab or adalimumab. Multivariate linear regression analyses were performed using the absolute change in 28 joint count disease activity score (DAS28) between baseline and 6-month follow-up as the outcome variable, adjusting for confounders. p Values <0.05 were considered statistically significant and associated markers were genotyped in an additional 322 samples. Analysis was performed in the combined cohort of 1334 subjects with RA treated with anti-TNF. RESULTS: In the combined analysis, SNPs mapping to AFF3 and CD226 had a statistically significant association with the response to anti-TNF treatment under an additive model. The G allele at rs10865035, mapping to AFF3, was associated with an improved response to anti-TNF treatment (coefficient -0.14 (95% CI -0.25 to -0.03), p=0.015). At the CD226 SNP rs763361, the C allele conferred reduced response to treatment (coefficient 0.11 (95% CI 0.00 to 0.22), p=0.048). CONCLUSION: These results suggest that AFF3 and CD226, two confirmed RA susceptibility genes, have an additional role in influencing the response to anti-TNF treatment.


Subject(s)
Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/genetics , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adult , Aged , Antigens, Differentiation, T-Lymphocyte/genetics , Cohort Studies , Female , Genetic Markers , Genetic Predisposition to Disease , Genotype , Humans , Male , Middle Aged , Nuclear Proteins/genetics , Polymorphism, Single Nucleotide , Treatment Outcome
11.
Ann Rheum Dis ; 69(7): 1315-20, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20448286

ABSTRACT

OBJECTIVE: To determine whether genetic variation within genes integral to the Toll-like receptor (TLR) and NFkappaB signalling systems, two cardinal regulators of inflammatory and immune responses, contributes towards the observed variation in response to tumour necrosis factor (TNF) blocking agents in patients with rheumatoid arthritis (RA). METHODS: Pairwise-tagging single nucleotide polymorphisms (SNPs) spanning 24 candidate genes were selected and genotyped in a large UK cohort of patients receiving anti-TNF therapy for RA. Multivariate regression analyses were performed to test association between individual genotypes, under an additive model, and treatment response at 6 months' follow-up assessed using both the absolute change in 28-joint count Disease Activity Score (DAS28) and the European League Against Rheumatism (EULAR) response criteria. Analyses were performed across subgroups comprising etanercept-, infliximab- and infliximab/adalimumab-treated patients as well as the combined anti-TNF-treated cohort. p Values <0.05 were considered statistically significant. RESULTS: A total of 187 SNPs were successfully genotyped and analysed in 909 patients. Eight SNPs spanning six genes demonstrated nominal evidence of association with response (DAS28) across the anti-TNF-treated subgroups, six of which were restricted to etanercept-treated patients. Twelve SNPs spanning nine genes demonstrated nominal evidence of association with treatment response (DAS28 and/or EULAR) across the combined anti-TNF cohort. These included SNPs mapping to MyD88 (rs7744) and CHUK (rs11591741), which were associated under each model applied (etanercept-treated and combined anti-TNF cohort analysis (DAS28 and EULAR)). CONCLUSIONS: Several SNPs mapping to the TLR and NFkappaB signalling systems demonstrated association with anti-TNF response as a whole and, in particular, with response to etanercept. Validation of these findings in an independent cohort is now warranted.


Subject(s)
Arthritis, Rheumatoid/drug therapy , NF-kappa B/genetics , Polymorphism, Single Nucleotide , Toll-Like Receptors/genetics , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adalimumab , Adult , Aged , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal, Humanized , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/genetics , Epidemiologic Methods , Etanercept , Female , Genotype , Humans , Immunoglobulin G/therapeutic use , Infliximab , Male , Middle Aged , Receptors, Tumor Necrosis Factor/therapeutic use , Signal Transduction/genetics , Treatment Outcome
12.
Int J Pharm ; 572: 118816, 2019 Dec 15.
Article in English | MEDLINE | ID: mdl-31678527

ABSTRACT

Amorphous solid dispersion (ASD) is one of the most promising strategies for improving the solubility of active pharmaceutical ingredients (APIs) with low aqueous solubility. Solvent-based techniques such as electrospinning (ES), spray-drying (SD) and rotary evaporation (RE), have all previously been shown to be effective techniques for formulating ASDs. To date however, the effect of these processing techniques on the physicochemical properties and ASD homogeneity or "quality of ASD" produced remains largely unexplored. This work uses ibuprofen (IBU) as a model BCS class II API with two cellulosic excipients, HPMCAS and HPMCP-HP55 to produce ASDs by employing ES, SD and RE processing techniques. The physicochemical, morphological and dissolution properties of each sample were evaluated and the ASD forming strengths of each of the polymers were assessed using Differential Scanning Calorimetry (DSC). Principal |Component Analysis (PCA) of Raman spectra of crystalline and amorphous IBU was employed for qualitative analysis of ASD homogeneity and subsequent ASD stability during long-term storage. Results show that while ASD formation is predominantly dependent on API:excipient ratio, the ASD homogeneity is highly dependent on processing technique. Dissolution studies show that electrospun samples had the highest API release rate due to their fibrous morphology and higher specific surface area. However, these samples were the least homogenous of all ASDs produced thereby potentially influencing sample stability during long term storage. In addition, the higher melting point depression, higher Tg, and increased abundance of functional groups suitable for hydrogen bonding, show HPMCAS to be a significantly better ASD co-former when compared with HPMCP-HP55.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Chemistry, Pharmaceutical , Ibuprofen/administration & dosage , Polymers/chemistry , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Calorimetry, Differential Scanning , Drug Compounding , Drug Liberation , Drug Stability , Drug Storage , Excipients/chemistry , Hydrogen Bonding , Ibuprofen/chemistry , Methylcellulose/analogs & derivatives , Methylcellulose/chemistry , Solubility , Solvents/chemistry
13.
Int J Pharm ; 544(1): 242-253, 2018 Jun 10.
Article in English | MEDLINE | ID: mdl-29689366

ABSTRACT

Downstream processing aspects of a stable form of amorphous itraconazole exhibiting enhanced dissolution properties were studied. Preparation of this ternary amorphous solid dispersion by either spray drying or hot melt extrusion led to significantly different powder processing properties. Particle size and morphology was analysed using scanning electron microscopy. Flow, compression, blending and dissolution were studied using rheometry, compaction simulation and a dissolution kit. The spray dried material exhibited poorer flow and reduced sensitivity to aeration relative to the milled extrudate. Good agreement was observed between differing forms of flow measurement, such as Flow Function, Relative flow function, Flow rate index, Aeration rate, the Hausner ratio and the Carr index. The stability index indicated that both powders were stable with respect to agglomeration, de-agglomeration and attrition. Tablet ability and compressibility studies showed that spray dried material could be compressed into stronger compacts than extruded material. Blending of the powders with low moisture, freely-flowing excipients was shown to influence both flow and compression. Porosity studies revealed that blending could influence the mechanism of densification in extrudate and blended extrudate formulations. Following blending, the powders were compressed into four 500 mg tablets, each containing a 100 mg dose of amorphous itraconazole. Dissolution studies revealed that the spray dried material released drug faster and more completely and that blending excipients could further influence the dissolution rate.


Subject(s)
Antifungal Agents/chemistry , Drug Compounding/methods , Itraconazole/chemistry , Desiccation/methods , Drug Liberation , Excipients/chemistry , Hot Temperature , Microscopy, Electron, Scanning , Particle Size , Powders , Rheology , Tablets
14.
J Pharm Sci ; 107(5): 1372-1382, 2018 05.
Article in English | MEDLINE | ID: mdl-29410037

ABSTRACT

The optimal design of amorphous solid dispersion formulations requires the use of excipients to maintain supersaturation and improve physical stability to ensure shelf-life stability and better absorption during intestinal transit, respectively. Blends of excipients (surfactants and polymers) are often used within pharmaceutical products to improve the oral delivery of Biopharmaceutical Classification System class II drugs. Therefore, in this study, a dissolution enhancer, poloxamer 407 (P407), was investigated to determine its effect on the dissolution properties and on the amorphous nature of the active pharmaceutical ingredient contained in the formulation. Phase solubility studies of indomethacin (INM) in aqueous solutions of P407 and poly(vinylpyrrolidone-vinyl acetate copolymer) showed an increase in the kinetic solubility of INM compared with the pure drug at 37°C with a Ka value of 0.041 µg/mL. The solid dispersions showed a higher dissolution rate when compared to pure and amorphous drugs when performed in pH buffer 1.2 with a kinetic solubility of 21 µg/mL. The stability data showed that the amorphous drug in solid solutions with poly(vinylpyrrolidone-vinyl acetate copolymer) and P407 remained amorphous, and the %P407 loading had no effect on the amorphous stability of INM. This study concluded that the amorphous solid dispersion contributed to the increased solubility of INM.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/chemistry , Epoxy Compounds/chemistry , Ethylene Oxide/chemistry , Excipients/chemistry , Indomethacin/chemistry , Poloxamer/chemistry , Povidone/analogs & derivatives , Crystallization , Drug Stability , Phase Transition , Povidone/chemistry , Solubility , Surface-Active Agents/chemistry
15.
Mol Nutr Food Res ; 62(22): e1800411, 2018 11.
Article in English | MEDLINE | ID: mdl-30192066

ABSTRACT

SCOPE: Inadequate maternal folate intake is associated with increased childhood acute lymphoblastic leukemia (ALL) risk. Folate provides methyl groups for DNA methylation, which is dramatically disrupted in ALL. Whether or not maternal folate (and related B-vitamin) intake during pregnancy may affect ALL risk via influencing DNA methylation is investigated. METHODS AND RESULTS: Genes in which methylation changes are reported both in response to folate status and in ALL are investigated. Folate-responsive genes (n = 526) are identified from mouse models of maternal folate depletion during pregnancy. Using published data, 2621 genes with persistently altered methylation in ALL are identified. Overall 25 overlapping genes are found, with the same directional methylation change in response to folate depletion and in ALL. Hypermethylation of a subset of genes (ASCL2, KCNA1, SH3GL3, SRD5A2) in ALL is confirmed by measuring 20 patient samples using pyrosequencing. In a nested cohort of cord blood samples (n = 148), SH3GL3 methylation is inversely related to maternal RBC folate concentrations (p = 0.008). Furthermore, ASCL2 methylation is inversely related to infant vitamin B12 levels. (p = 0.016). CONCLUSION: Findings demonstrate proof of concept for a plausible mechanism, i.e., variation in DNA methylation, by which low intake of folate, and related B-vitamins during pregnancy may influence ALL risk.


Subject(s)
DNA Methylation , Folic Acid/blood , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Vitamin B 12/blood , 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/genetics , Adaptor Proteins, Signal Transducing/genetics , Animals , Basic Helix-Loop-Helix Transcription Factors/genetics , Erythrocytes/metabolism , Female , Folic Acid/administration & dosage , Humans , Infant , Infant, Newborn , Kv1.1 Potassium Channel/genetics , Male , Membrane Proteins/genetics , Mice, Inbred C57BL , Mothers , Pregnancy
16.
Am J Ophthalmol ; 143(4): 656-62, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17306754

ABSTRACT

PURPOSE: We identified families with autosomal dominant optic atrophy (ADOA), determined the number and type of OPA1 mutations, and investigated the phenotypic variation and penetrance in ADOA Australian pedigrees. DESIGN: Cross-sectional genetics study. METHODS: Probands were identified on the basis of characteristic clinical features of ADOA. We screened the OPA1 gene using single-strand conformational polymorphism, heteroduplex analysis (SSCP/HA), or by direct sequencing. Penetrance for pedigrees in which a mutation of OPA1 had been identified was calculated initially using all recruited individuals, and subanalysis was performed using only those families for which there was total recruitment of siblings. RESULTS: A total of 406 patients from 17 pedigrees were recruited, and OPA1 mutations were identified in 11/17 (65%) of these. The mean age at clinical examination was 38.2 +/- 19.9 years (median age, 35 years; range, four to 83 years). The median best-corrected visual acuity in OPA1-mutation carriers was 20/70 (range, 20/16 to hand movements [HM]). The penetrance in Australian ADOA pedigrees in the families with complete sibling recruitment was 82.5%. On the other hand, overall penetrance for all individuals harboring an OPA1 mutation was 88%. CONCLUSIONS: OPA1 mutations were identified in 11/17 (65%) of the ADOA pedigrees in this study. The penetrance in our cohort was lower than originally described (82.5% vs 98%) but higher than some recent studies since the availability of genotyping. It is anticipated that this figure would be even lower as more asymptomatic individuals are identified. There are likely to be other genetic and environmental modifiers influencing disease penetrance.


Subject(s)
GTP Phosphohydrolases/genetics , Mutation , Optic Atrophy, Autosomal Dominant/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Cross-Sectional Studies , DNA Mutational Analysis , Heteroduplex Analysis , Humans , Middle Aged , Pedigree , Penetrance , Phenotype , Polymorphism, Single-Stranded Conformational , Visual Acuity
17.
Eur J Pharm Biopharm ; 119: 36-46, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28559112

ABSTRACT

Piracetam was investigated as a model API which is known to exhibit a number of different polymorphic forms. It is freely soluble in water so the possibility exists for polymorphic transformations to occur during wet granulation. Analysis of the polymorphic form present during lab-scale wet granulation, using water as a granulation liquid, was studied with powder X-ray diffraction and Raman spectroscopy as off-line and inline analysis tools respectively. Different excipients with a range of hydrophilicities, aqueous solubilities and molecular weights were investigated to examine their influence on these solution-mediated polymorphic transitions and experimental results were rationalised using molecular modelling. Our results indicated that as an increasing amount of water was added to the as-received piracetam FIII, a greater amount of the API dissolved which recrystallised upon drying to the metastable FII(6.403) via a monohydrate intermediary. Molecular level analysis revealed that the observed preferential transformation of monohydrate to FII is linked with a greater structural similarity between the monohydrate and FII polymorph in comparison to FIII. The application of Raman spectroscopy as a process analytical technology (PAT) tool to monitor the granulation process for the production of the monohydrate intermediate as a precursor to the undesirable metastable form was demonstrated.


Subject(s)
Chemistry, Pharmaceutical/methods , Piracetam/analysis , Piracetam/chemistry , Neuroprotective Agents/analysis , Neuroprotective Agents/chemistry , Spectrum Analysis, Raman/methods , X-Ray Diffraction/methods
18.
Int J Pharm ; 519(1-2): 365-372, 2017 Mar 15.
Article in English | MEDLINE | ID: mdl-28131850

ABSTRACT

A range of 17 ternary formulations of itraconazole (ITZ), HPMCP and Soluplus have been manufactured using spray drying. These amorphous solid dispersions (ASDs) were very stable against crystallisation and ITZ was found to be amorphous in all formulations after one year at 40°C/75% RH. A number of solid state analytical techniques including PXRD, DSC, small angle X-ray scattering, FTIR and solid state NMR were used to characterise the physicochemical properties of the ASDs following processing and storage and to assess any interactions between components. Microtrac laser scattering analysis revealed a relationship between polymer levels and particle size distribution (PSD). Dissolution studies indicated that higher Soluplus content in the formulation resulted in higher concentrations of ITZ in acidic media.


Subject(s)
Itraconazole/chemistry , Polyethylene Glycols/chemistry , Polyvinyls/chemistry , Calorimetry, Differential Scanning/methods , Chemistry, Pharmaceutical/methods , Crystallization/methods , Drug Compounding/methods , Excipients/chemistry , Particle Size , Polymers/chemistry , Solubility , X-Ray Diffraction/methods
19.
Int J Pharm ; 532(1): 603-611, 2017 Oct 30.
Article in English | MEDLINE | ID: mdl-28923766

ABSTRACT

The aim of this study was to evaluate a novel combination of hydroxypropyl methylcellulose phthalate (HPMCP-HP-50) and Soluplus® polymers for enhanced physicochemical stability and solubility of the produced amorphous solid dispersions (ASDs). This was achieved using hot melt extrusion (HME) to convert the crystalline active pharmaceutical ingredient (API) into a more soluble amorphous form within the ternary systems. Itraconazole (ITZ), a Biopharmaceutics Classification System class II (BCS II) API, was selected as the model drug. The ASDs were characterized by Powder X-Ray diffraction (PXRD), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Solid State Nuclear Magnetic Resonance (ssNMR) and dissolution studies. The data showed that the ASDs were physically and chemically stable at 20°C and 50% RH over 12 months. PXRD results indicated that the ITZ in the ASDs was in the amorphous state and no recrystallization occurred. DSC scans confirmed that each formulation exhibited a single intermediate glass transition (Tg), around 96.4°C, indicating that ITZ was completely miscible in the polymeric blends of HPMCP and Soluplus® at up to 30% (w/w) drug loading and that the two polymers were miscible with each other in the presence of ITZ. The FTIR analysis indicated the formation of strong hydrogen bonding between ITZ, HPMCP and Soluplus®. The dissolution end-point of the ASDs was determined to be approximately 10 times greater than that of the crystalline ITZ.


Subject(s)
Drug Compounding , Itraconazole/chemistry , Methylcellulose/analogs & derivatives , Polyethylene Glycols/chemistry , Polyvinyls/chemistry , Chemistry, Pharmaceutical , Hot Temperature , Methylcellulose/chemistry , Solubility
20.
PLoS One ; 8(10): e76506, 2013.
Article in English | MEDLINE | ID: mdl-24098518

ABSTRACT

This study examines the relationship between common genetic variation within DNA methyltransferase genes and inter-individual variation in DNA methylation. Eleven polymorphisms spanning DNMT1 and DNMT3B were genotyped. Global and gene specific (IGF2, IGFBP3, ZNT5) DNA methylation was quantified by LUMA and bisulfite Pyrosequencing assays, respectively, in neonatal cord blood and in maternal peripheral blood. Associations between maternal genotype and maternal methylation (n (≈) 333), neonatal genotype and neonatal methylation (n (≈) 454), and maternal genotype and neonatal methylation (n (≈) 137) were assessed. The findings of this study provide some support to the hypothesis that genetic variation in DNA methylating enzymes influence DNA methylation at global and gene-specific levels; however observations were not robust to correction for multiple testing. More comprehensive analysis of the influence of genetic variation on global and site specific DNA methylation is warranted.


Subject(s)
DNA (Cytosine-5-)-Methyltransferases/genetics , DNA Methylation , Genotype , Adult , Cation Transport Proteins/genetics , CpG Islands , DNA (Cytosine-5-)-Methyltransferase 1 , Female , Genetic Loci , Humans , Infant, Newborn , Insulin-Like Growth Factor Binding Protein 3/genetics , Insulin-Like Growth Factor II/genetics , Linkage Disequilibrium , Polymorphism, Single Nucleotide , Pregnancy , DNA Methyltransferase 3B
SELECTION OF CITATIONS
SEARCH DETAIL