Analysis of drug polymorphism by diffuse reflectance visible spectroscopy- a novel approach

The existence of polymorphic forms of drug substances has implications for therapeutic performance, handling and storage. This study investigates the development of a novel approach to surface analysis of drug polymorphs, with the aim of extending the capabilities of this approach to perform real time analysis of polymorphic transformation during pharmaceutical product development. This was achieved here, using diffuse reflectance visible spectroscopy (DRVS) and the colour change which occurs when pH indicator dyes are deposited on the surface. The pH indicators used were phenol red (PR), thymol blue (TB) and methyl red (MR). Two polymorphs each of indomethacin (IMC), carbamazepine (CBZ), caffeine (CFN), sulfanilamide (SFN) and furosemide (FRS) were examined. The interaction of the adsorbed dye with each of the polymorphs showed different behaviour, manifested by different colours. An analysis of the crystal structures and the acid/base properties of the drug molecules provided a rationalisation for the different colours exhibited by the polymorphs‘ surfaces. The least stable form of each polymorphic pair studied showed more extensive interaction with the adsorbed dye molecules. Observed colour reveal underlying differences at a molecular level between the surfaces of pairs of polymorphs. The different colours exhibited by the indomethacin polymorphs were further examined using hygroscopicity studies, contact angle measurements and computer simulation. The contact angles of several liquids with the polymorph surface were measured in order to characterise the nature of the functional groups exposed on the surface of the polymorphs. The surface structure and external morphologies of polymorphs were predicted by molecular modelling using the attachment energy model. The predicted morphology was confirmed by scanning electron micrographs (SEM) and the miller index of the dominant face was confirmed by X-ray powder diffraction (XRD). Results revealed that although the surfaces of both polymorphs are largely hydrophobic, the metastable form- IMC-α has a greater number of polar functional groups on the surface. Further measurements were carried out using DRVS and adsorbed TB to study the kinetics of the solid-state transformation of SFN- to SFN-. The rate of transformation was followed at 128ºC by monitoring the ratio of the two DRVS bands at 454 nm and 604 nm. The kinetic data was analysed using sixteen solid-state kinetic models to obtain the best fit. The thermally induced polymorphic transformation of the SFN-β (particle size of ≥ 450μm) can be best described by the first order kinetic model (R2 = 0.992) with a rate constant, k of 2.43 x 102 s-1. The DRVS instrument used herein is not adapted for in situ studies; however, because of its non-destructive interaction with the sample and rapid data collection time of 5s per spectrum, it does offer considerable potential as a tool for real time monitoring of polymorphic transformation

Investigating the bioprotective properties of sugars

The purpose of this study was to investigate the stabilizing properties of osmolytes, specifically sugars on biomolecule such as protein. The strategy used in this study involved the utilisation of surfactant-rich micelles; where by the impact sugars have on the free energy of exposure of hydrocarbon groups present within the surfactant micelles was examined. The observation made for sugar-surfactant study was then applied to explain the stabilisation of the native structure and thus the physiologically active form of the protein by sugars. The sugars that have been studied include sucrose, trehalose, maltose, raffinose and mannitol. The surfactants studied were sodium decyl sulphate (SDeS), sodium dodecyl sulphate (SDS) and sodium tetradecyl sulphate (STS). Tensiometry was used to examine the impact of sugars on the critical micelle concentrations (CMC), Gibbs free energy change of micellization ( Gmic), surface pressure, surface excess concentration and area occupied per surfactant molecule. The free energy penalty of hydrocarbon chain exposure was obtained from the Gibbs free energy change of demicellization( Gdemic) which is equal but opposite in sign to the Gmic. Measurements were carried out to elucidate the influence of sugar on the aforementioned surfactant properties as a function of increasing sugar concentration. Isothermal titration calorimetry (ITC) was then used to study -sugar surfactant interactions to give enthalpy ( Hmic) and entropy ( Smic) of micellization in addition to CMC and Gmic, thus obtaining a full thermodynamic characterisation, complementing the results obtained by tensiometry. Tensiometric results revealed that at increasing concentration of sugar, the CMC of the surfactants was decreased and a more negative Gmic was obtained. ITC results revealed a similar trend for the effect of sugar on CMC and Gmic while the Hmic and Smic was increased in the presence of the sugars. The results from surfactant studies suggest an increase in the free energy penalty of hydrocarbon group exposure to the aqueous environment, due to an unfavourable interaction between the hydrophobic groups and the aqueous sugar solution. Consequently, the aggregation process is thermodynamically favoured and more spontaneous in sugar solutions. For instance in SDeS the Gmic in water and in sugar solution showed that micellization was more favourable in sugar solution ( Gmic = -19.14 kJ mol−1 at 1.0M Trehalose) than in water ( Gmic = -18.44 kJ mol−1). In addition, significant increases in surface pressure of the surfactants in the presence of sugars suggest an enhancement of the surface activity of the surfactants. Increases in area occupied per surfactant molecules in the presence of sugars suggest increase in the size of the head group area thus, possible interactions between surfactant head group – sugar or sugar-water mediated interactions. Also increases Hmic in comparison to lower values of Smic obtained by calorimetry suggest possible hydrogen bonding. In conclusion, surfactant studies suggest that sugars would stabilize biological structures by a combination of both an exclusion from the hydrophobic group due to unfavourable interactions between the hydrophobic groups and possible polar interactions between polar groups. Differential scanning calorimetry (DSC) was used to study and characterise the effect of the sugars on the thermal stability of RNase A. The results revealed an increase the thermal stability of RNase A as shown by higher Tm values in the presence of sugars. Results obtained from surfactant studies were then related to DSC results, a linear relationship between the Tm and CMC values suggests a similar mechanism. Hence, though proteins are large complex molecules, their interaction with sugars or other small solutes could be related to simple model systems such as micelles

Cooking characteristics, chemical composition and protein quality of newly developed genotypes of pigeonpea (Cajanus cajan L)

Eight newly developed pigeonpea genotypes (ICPL 87, ICPL 151, ICPL 270, ICPL 366, ICPL 87051, ICPL 87063, ICPL 87067, and ICPV 1), and the two controls (BDN 2 and C 11) were analysed for cooking quality parameters and chemical composition, including amino acids and minerals. Protein quality was evaluated by determining the true protein digestibility, biological value, net protein utilisation (NPU), and utilisable protein. These genotypes differed significantly (P < 0–01) in the dhal cooking time. Sensory properties of dhal of these genotypes were found to be within the acceptable range, even though there were considerable differences among genotypes. Dhal protein, calcium, magnesium, zinc, and iron contents of these genotypes showed noticeable differences. Calcium content of ICPL 87067 was the highest (85-6 mg per 100 g) and of ICPL 87 the lowest (54-4 mg per 100 g) indicating large differences among the newly developed genotypes. No noticeable differences in sulphur-containing amino acids of these genotypes were observed. NPU was the highest (65–4%) for ICPL 366 and the lowest (56–6%) for ICPL 270 and ICPL 87067 indicating significant (P < 0–01) differences among genotypes studied

Genotypic and environmental factors affecting seed coat durability of field peas and dehulling characteristics of other legumes

Thesis in partial fulfillment of the requirements for the degree of Master of Science, University of Saskatchewan, 198

RELATIONS BETWEEN GREECE AND WEST AFRICAN COUNTRIES ESPECIALLY NIGERIA

THIS INTRODUCTIONS COVERS THE SHORT HISTORY OF NIGERIA AND THE BASIC CHARACTERI STICS. CHAP. 1 IS ABOUT THE AIMS AND THE GENERAL PRINCIPLES OF THE NIGERIAN FOREIGN POLICIES & HER CHOICE. CHAP. 2 EXAMINES THE POLITICS OF NIGERIA OILWELTH. CHAP. 3 ALSO EXAMINES THE ROLE OF NIGERIA IN OPEC. CHAP. 4. EXAMINES THE RELATIONS BETWEEN NIGERIA AND THE EEC WITHIN THE ANALYSIS OF THE ASSOCIA TION AGREEMENT EEC-ACP. CHAP. 5 DEALS WITH THE RELATIONS BETWEEN NIGERIA AND THE FORMER SOCIALIST COUNTRIES OF EASTERN EUROPE. CHAP. 6 EXAMINES THE ROLE OF NIGERIA IN THE NON-ALIGNED MOVEMENT AND ALSO IN CHAP. 7. EXAMINES THERELATIONS BETWEEN GREECE AND NIGERIA.Η ΕΙΣΑΓΩΓΗ ΠΕΡΙΛΑΜΒΑΝΕΙ ΑΝΑΦΟΡΑ ΣΤΑ ΒΑΣΙΚΑ ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ ΚΑΙ ΣΤΗΝ ΙΣΤΟΡΙΑ ΤΗΣΝΙΓΗΡΙΑΣ. ΤΟ ΚΕΦ. 1. ΑΝΑΦΕΡΕΤΑΙ ΣΤΟΥΣ ΣΤΟΧΟΥΣ ΚΑΙ ΤΙΣ ΑΡΧΕΣ ΤΗΣ ΝΙΓΗΡΙΑΣ ΕΞΩΤΕ ΡΙΚΗΣ ΠΟΛΙΤΙΚΗΣ ΚΑΙ ΤΙΣ ΕΠΕΛΟΓΕΣ ΤΗΣ. ΤΟ ΔΕΥΤΕΡΟ ΚΕΦΑΛΑΙΟ ΕΡΕΥΝΑ ΤΟ ΡΟΛΟΤΗΣ ΝΙΓΗΡΙΑΣ ΣΤΗΝ ΠΕΤΡΕΛΑΙΚΗ ΠΟΛΙΤΙΚΗ. ΤΟ ΤΡΙΤΟ ΚΕΦΑΛΑΙΟ ΣΤΙΣ ΣΧΕΣΕΙΣ ΤΗΣ ΝΙΓΗΡΙΑΣ ΜΕ ΤΟΝ ΟΠΕΚ. ΣΤΟ ΤΕΤΑΡΤΟ ΚΕΦ. ΟΙ ΣΧΕΧΕΙΣ ΤΗΣ ΝΙΓΗΡΙΑΣ-ΕΟΚ ΜΕΣΑ ΚΥΡΙΩΣ ΑΠΟ ΤΗΝ ΑΝΑΛΥΣΗ ΤΩΝ ΣΥΝΘΗΚΩΝ ΤΗΣ LOME. ΤΟ ΠΕΜΠΤΟ ΚΕΦΑΛΑΙΟ ΑΦΟΡΑ ΣΤΙΣ ΣΧΕΣΕΙΣ ΤΗΣ ΝΙΓΗΡΙΑΣ ΜΕ ΤΙΣ ΣΟΣΙΑΛΙΣΤΙΚΕΣ ΧΩΡΕΣ ΤΗΣ ΑΝ. ΕΥΡΩΠΗΣ. ΣΤΟ ΕΚΤΟ ΚΕΦΑΛΑΙΟ Ο ΡΟΛΟΣ ΤΗΣ ΝΙΓΗΡΙΑΣ ΣΤΟ ΚΙΝΗΜΑ ΤΩΝ ΑΔΕΣΜΕΥΤΩΝ ΕΝΩ ΣΤΟ ΕΠΟΜΕΝΟ ΚΕΦ. ΟΙ ΣΧΕΣΕΙΣ ΤΗΣ ΕΛΛΑΔΟΣ ΜΕ ΤΗ ΝΙΓΗΡΙΑ

How black West African migrants perceive cancer

This paper examines health beliefs, knowledge and perceptions of cancer among two Anglophone black African migrant communities in Luton, UK. Using a focus group approach, 53 participants from the Ghanaian and Nigerian migrant communities were recruited for separate and mixed male and female groups as well as separate and mixed groups of different nationalities and religious backgrounds. The study showed that the participants have both biomedical and faith-based understandings of cancer. They will seek medical help as quickly as possible, as well as expressing their health concerns to God in prayer. Silence, concealment and stigma were identified as barriers that prevent some individuals from accessing cancer services. It is hoped that the findings of this study may contribute to cancer awareness campaigns as well as forming the basis for future research among this and other under-researched black minority migrant communities in the UK. Professionals working with these communities need to have an awareness of these perceptions in order to ensure that these populations receive culturally sensitive care

Black African migrants' perceptions of cancer: are they different from those of other ethnicities, cultures and races?

PurposeCancer discussion is perceived as a taboo subject among different cultures and societies including Africans. This perception has caused limited knowledge about the disease and prevented some from seeking early diagnosis and treatment. With West Africans now living in western societies where cancer is openly discussed, this study aims to explore how black Africans perceive the disease and the implications for healthcare.Design/methodology/approachFive focus groups of 53 persons from Ghanaian and Nigerian migrant communities in Luton participated in this study.FindingsPerceptions of fear, shame and denial were identified as key elements of how people perceive and react to cancer among the study population.Originality/valueSecrecy and apprehension were identified as major barriers and have prevented some from adequately accessing and utilizing cancer facilities in the country. The feelings of fear, secrecy and stigma associated with the disease across different ethnic groups, cultures and nations also exist among the study population. These outcomes are similar and chime with published findings of limited cancer perception research among other ethnic groups and races here in the UK and across the globe.</jats:sec

Soil-To-Fluted Pumpkin Transfer Of Natural Radionuclides In Farm Lands In Akwa Ibom State, Nigeria

This work is aimed at evaluating the radionuclides transfer from soil to fluted pumpkin in farm lands in Akwa Ibom State, Nigeria. The activity concentrations of 238U, 232Th, 226Ra and 40K were measured in fluted pumpkin and soil samples using high purity Germanium (HPGe) Detector. The mean activity concentrations of 238U, 226Ra, 232Th and 40K in the soils samples ranged from 43. 26 ± 2.53 Bq/Kg to 80.11± 4.26 Bq/kg, 17.45 ± 0.96 Bq/ Kg to 28.71 ± 1.48 Bq/Kg, 23.83 ± 1.27 Bq/ Kg to 53.27 ± 2.84 Bq/Kg and 4.02 ± 0.36 to 43.83 ± 2.35 Bq/Kg respectively. The mean activity concentrations of radionuclides in the fluted pumpkin for  40K, 238U, 232Th and  226Ra ranged from 805.28 ± 42.89 to  1582.93 ± 83.72 Bq/Kg,  below detection limit (BDL) to 86.96 ± 5.63 Bq/Kg,  4.81 ± 0.84 to 46 .23  ±3. 45 Bq/Kg and 7. 17 ± 0.83 to 25.28 ± 1.58 Bq/Kg respectively.  The radionuclides transfer factor (TF) obtained in this work varies from farm to farm and ranged from 10.36 to 87.84 for 40K, BDL to 1. 28 for 238U, 0.13 to 0.95 for 232Th and 0.31 to 0.92 for 226Ra. The TF values for radionuclides obtained for this work were lower than 1 except for 40K.  This suggests that consumption of the fluted pumpkin in these areas might not pose a high radiological hazard to its consumers while for 40K, the human body has an internal mechanism to eliminate its excess in the body