Babur Chowdhry

University of Greenwich · School of Science

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor in Chief following the internal investigation at the University of Sussex and University of Greenwich. The investigation found that...

The objective of the research reported herein is to compare the compaction properties of three different chitin extracts from the organisms most used in the seafood industry; namely crabs, shrimps and squids. The foregoing is examined in relation to their polymorphic forms as well as compression and compaction behavior. Chitin extracted from crabs...

The objective of the research reported herein is to compare the compaction properties of three different chitin extracts from the organisms most used in the seafood industry; namely crabs, shrimps and squids. The foregoing is examined in relation to their polymorphic forms as well as compression and compaction behavior. Chitin extracted from crabs...

In this paper, new scientific insights in relation to the re-compaction of microcrystalline cellulose (MCC; Avicel ®® PH-101) under specific compaction conditions are reported. MCC was subjected to multiple compaction cycles (1st, 2nd, and 3rd) under high compaction pressures, up to 20,000 kPa, using a roller compactor of 100 kg/h capacity. Initial...

Calcium carbonate must be processed before it can be compressed into tablets. This study examined the compression behavior of calcium carbonate powder when granulated with different binders. Hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose (HPMC) and sodium alginate (Na-Alg), were chosen at different concentrations as binding agents. Da...

Chitin has been investigated in the context of finding new excipients suitable for direct compression, when subjected to roller compaction. Ball milling was concurrently carried out to compare effects from different energy or stress-inducing techniques. Samples of chitin powders (raw, processed, dried and humidified) were compared for variations in...

The subject of our research is the optimization of direct compression (DC), controlled release drug matrices comprising chitosan/xanthan gum. The foregoing is considered from two main perspectives; the use of low molecular weight chitosan (LCS) with xanthan gum (XG) and the determination of important attributes for direct compression of the mixture...

In this study, novel 3D printed polymeric microneedle arrays were fabricated for enhanced cisplatin delivery to A-431 epidermoid skin tumours for cancer treatment. The microneedles were built by selectively photopolymerising consecutive layers of a biocompatible photopolymer resin using stereolithography (SLA), followed by coating of cisplatin form...

Changes in tensile properties and the glass transition temperature (Tg) of plasticized polymer films are typically attributed to molecular mobility, often with no empirical data to support such an assertion. Herein solvent cast HPMC films containing varying amounts of PEG, as the plasticizer, were used to assess the dependence of tensile properties...

The development and evaluation of a controlled-release (CR) solid dosage form comprising xanthan gum (XG), low molecular weight chitosan (LCS) and metoprolol succinate (MS) is reported. The research is, partly, based upon the utilization of computational tools; in this case molecular dynamics simulations (MDs) and response surface method (RSM), in...

Roller compaction was used to prepare a direct compressed lactose excipient using crystalline α-lactose monohydrate. The effect of various roller compaction process parameters (compaction pressure, compaction repetition, and speed ratio) on the characteristics of compacted α-lactose monohydrate were investigated. The results were compared to the da...

Naturally occurring polysaccharides and/or their chemically modified derivatives have been widely investigated in relation to their use as components of controlled release systems for drug delivery. The aforementioned is due, in part, to their distinct properties such as abundant availability and biocompatibility as well as environmental and econom...

Hydrophilic matrices composed of chitosan (CS) and xanthan gum (XG) complexes are of pharmaceutical interest in relation to drug delivery due to their ability to control the release of active ingredients. Molecular dynamics simulations (MDs) have been performed in order to obtain information pertaining to the effect of the state of protonation and...

The crystal structure of a commercially available form of human recombinant (HR) insulin, Insugen (I), used in the treatment of diabetes has been determined to 0.92 Å resolution using low temperature, 100 K, synchrotron X-ray data collected at 16,000 keV (λ = 0.77 Å). Refinement carried out with anisotropic displacement parameters, removal of main-...

This study investigated the surface of semi-crystalline composite granules produced via a novel mechano-chemical process and assessed the effect of electrostatic charging. Ibuprofen (IBU), a model drug with low solubility and known associated processing challenges was loaded in composite granules to improve its processibility and dissolution rates....

Dehydrated DLPC, DMPC, DPPC and DSPC have been characterised at temperatures below the diacyl carbon chain-melting transition (Tm), using DSC. For the first time, the existence of pre-Tm transition processes, which are, usually, only observed in the colloidal/liposomal state of saturated phospholipids, has been detected for the dehydrated phosphati...

A continuous manufacturing process for pharmaceutical indomethacin-saccharine cocrystals was achieved by extrusion processing with high throughput. Down-stream milling and blending of the extrudates was followed by feeding the formulated cocrystals in a capsule-filling machine. By applying a quality by design approach, the process was optimized and...

Objectives: The aim of this study was to develop mucoadhesive oral strips using hot-melt extrusion as a continuous manufacturing process. Methods: Powder blends of ketoconazole, a water-insoluble drug - either hydroxypropyl methylcellulose (HPMC) or soluplus (SOL), sorbitol (SRB) and magnesium aluminometasilicate (MAS) were extruded to manufactu...

Background: Automated DBS direct elution systems are available that incorporate IS spray modules which, unlike conventional IS addition via the extraction solvent, apply IS prior to DBS samples prior to extraction, allowing analyte and IS to be coextracted. Results: IS spray system parameters were optimized to identify the conditions that produc...

The aim of the work reported herein was to study the effect of glucosamine HCl (GlcN·HCl) on the bioactivity (BA) of insulin, administered via subcutaneous (SC) and oral routes, in adult male Sprague Dawley rats. The oral insulin delivery system (insulin–chitosan reverse micelle [IC-RM]) was prepared by solubilizing insulin–chitosan (13 kDa) polyel...

The aim of the work reported herein was to implement process analytical technology (PAT) tools during hot melt extrusion (HME) in order to obtain a better understanding of the relationship between HME processing parameters and the extruded formulations. For the first time two in-line NIR probes (transmission and reflectance) have been coupled with...

IR and Raman spectra of eugenol, isoeugenol and methyl eugenol have been obtained in the liquid phase. Vibrational spectroscopic results are discussed in relation to computed structures and spectra of the low energy conformations of these molecules obtained from DFT calculations at the B3LYP/cc-pVTZ level. Although computed differences in vibration...

Automated DBS direct elution techniques eliminate the manual extraction burden of DBS bioanalysis, offer good quantitative performance, the ability to eliminate hematocrit-based assay bias, and, previous reports have demonstrated that significant increases in assay sensitivity compared with manual DBS extraction are possible. An investigation into...

This study aimed to develop and characterize stable films as potential protein delivery dressings to wounds. Films were prepared from aqueous gels of sodium alginate (SA) and glycerol (GLY) (SA:GLY 1:0, 1:1, 1:2, 2:3, 2:1, 4:3),. Purified recombinant glutathione-s-transferase (GST), green fluorescent protein (GFP) and GST fused in frame to GFP (GST...

Ion mobility mass spectrometry is used to measure the drift-time of an ion. The drift-time of an ion can be used to calculate the collision cross-section (CCS) in travelling wave ion mobility (e.g. Waters Synapt and Vion instruments) or directly determine the experimental CCS (e.g. Agilent 6560 instrument and many drift-tube instruments). A compari...

The effect of reduced (GSH) and oxidized (GSSG) glutathione on the bioactivity of insulin was studied. A polyelectrolyte complex (PEC) of insulin with low molecular weight chitosan (13 kDa) was prepared and characterized. The PEC was then solubilized, in the presence and absence of GSH and GSSG, in a reverse micelle consisting of oleic acid and two...

Hematocrit (HCT) based assay bias (composed of area and recovery bias) is an important contributing factor to the barriers that currently hinder the development and acceptance of dried blood spots (DBS) as a widely used quantitative bioanalytical sampling technique for regulatory studies. This article describes the evaluation of a practical interna...

This study describes the preparation, characterization and performance of a novel excipient for use in oro-dispersible tablets (ODT). The excipient (Cop-CM) consists of chitin and mannitol. The excipient with optimal physicochemical properties was obtained at a chitin: mannitol ratio of 2:8 (w/w) and produced by roll compaction (RC). Differential s...

The aim of the work reported herein was to investigate the effect of various low molecular weight chitosans (LMWCs) on the stability of insulin using USP HPLC methods. Insulin was found to be stable in a polyelectrolyte complex (PEC) consisting of insulin and LMWC in the presence of a Tris-buffer at pH 6.5. In the presence of LMWC, the stability of...

3-(Propan-2-ylidene)benzofuran-2(3H)-one, C11H10O2, crystallizes in the monoclinic space group P21/c with unit cell parametersa =7.1869(3), b = 18.0636(10), c = 13.1656(7) b= 96.763(3), V =1697.28(15) , Z = 8 (Z? = 2 independent molecules, A and B, per asymmetric unit), Dc = 1.363 g cm-3 and the linear absorption coefficient = 0.093 mm-1. The cry...

A novel approach employing variable-temperature X-ray powder diffraction (VTXRPD) was used to exploit its suitability as an off-line predictive tool to study the polymorphic transformations of paracetamol (PMOL) in melt-extruded hydrophilic polymer matrices. Physical mixtures (PMs) and extruded formulations of PMOL with either polyvinyl caprolactam...

The drug distribution on the surface of hot-melt extruded, pre-mixed hot-melt extruded and direct compressed tablet formulations was characterized by using scanning electron microscopy, energy dispersive X-ray spectroscopy (EDX) and confocal Raman spectroscopy. Formulations of paracetamol (PMOL) and Compritol(®) (C-888) were extruded using hot-melt...

In this study, a quality-by-design (QbD) approach was used to optimize the development of paracetamol (PMOL) sustained-release formulations manufactured by hot-melt extrusion (HME). For the purpose of the study, in-line near-infrared (NIR) spectroscopy as a process analytical technology (PAT) was explored while a design of experiment (DoE) was impl...

A solvent free process for the formation of Carbamazepine (CBZ) - trans Cinnamic acid (TCA) cocrystals, at stoichiometric ratios, was developed using continuous Hot Melt Extrusion processing. Physicochemical characterization of the CBZ-TCA extrudates included scanning electron microscopy (SEM) differential scanning calorimetry (DSC), X-ray powder d...

Ion mobility spectrometry-mass spectrometry (IMS-MS) offers an opportunity to combine measurements and/or calculations of the collision cross-sections and subsequent mass spectra with computational modelling in order to derive the three-dimensional structure of ions. IMS-MS has previously been reported to separate two components for the compound no...

γ-Aminobutyric acid (GABA), and its positional isomers dl-α-aminobutyric acid (AABA) and dl-β-aminobutyric acid (BABA) have been analysed, in the solid state, using thermally stimulated current (TSC) spectroscopy. Secondary relaxations in these molecules have been detected for the first time. GABA displays two secondary relaxations at 77 ± 2 °C and...

Sirolimus has recently been introduced as a therapeutic agent for breast and prostate cancer. In the current study, conventional and Stealth® liposomes were used as carriers for the encapsulation of sirolimus. The physicochemical characteristics of the sirolimus liposome nanoparticles were investigated including the particle size, zeta potential, s...

The decomposition behaviour of chlorogenic acid (CGA) was studied under inert (nitrogen) and oxidative (air) atmospheres by themogravimetric analysis (TGA). Thermal decomposition was found to be faster under an air atmosphere with a total weight change of 97 ± 1% compared to 61 ± 1% under a nitrogen atmosphere. At least 3 or 4 processes were observ...

The prevalence of allergic disease has rapidly increased over the last few decades causing a significant amount of health burden. This review aims to identify and evaluate the published scientific evidence concerning the effects of diet during infancy on the risks of developing allergic disease in order to provide a better understanding of the rela...

Maternal & Child Nutrition, 9 (S3). pp. 48-49. ISSN 1740-8695 (Print), 1740-8709.

The majority of active pharmaceutical ingredients (APIs) found in oral dosage forms have a bitter taste. Masking the unpleasant taste of bitter, APIs is a major challenge in the development of such oral dosage forms. Taste assessment is an important quality-control parameter for evaluating taste-masked formulations of any new molecular entity. Hot-...

The phenomenon of ion mobility (IM), the movement/transport of charged particles under the influence of an electric field, was first observed in the early 20th Century and harnessed later in ion mobility spectrometry (IMS). There have been rapid advances in instrumental design, experimental methods, and theory together with contributions from compu...

The study reported herein was conducted in order to establish the concentration of 20 essential and non-essential elements in a representative range of commercial infant foods in the UK targeted for infants aged between 6-12months. The primary objective of this study was to examine the nutritive values and safety of such complementary infant foods...

Lyophilized muco-adhesive wafers with optimum drug loading for potential buccal delivery have been developed. A freeze-annealing cycle was used to obtain optimized wafers from aqueous gels containing 2% κ-carrageenan (CAR 911), 4% pluronic acid (F127), 4.4% (w/w) polyethylene glycol with 1.8% (w/w) paracetamol or 0.8% (w/w) ibuprofen. Thermogravime...

Quantitative analyses of the macronutrient content of eight popular commercial 'ready-to-feed' baby meals for 6-9-month old infants in the UK market have been undertaken in order to ascertain their nutritional suitability in relation to the total daily dietary intake as well as nutritional profiling of the products. The chemical analyses conducted...

The chemical and physical modifications of native maize starch subjected to treatment with aqueous Na silicate have been investigated. The application of FTIR, DSC, XRPD, and NMR analysis is discussed herein with respect to the interaction of Na silicate with starch in relation to gelatinization. XRPD results indicate that Na silicate, in the ioniz...

Solid-state Raman and IR spectra of two polymorphic forms of each of three fenamates (flufenamic acid, mefenamic acid and tolfenamic acid) display subtle but highly reproducible differences. Many of these spectral differences can be ascribed to different conformations of these molecules, involving two of four possible orientations of one substitute...

A comprehensive series of aqueous solutions of four ethylene oxide–propylene oxide–ethylene oxide block copolymers (EPE) of varying concentrations have been prepared. The EPE molecules are amphiphilic with the P blocks providing the hydrophobic segment of the molecules and the E blocks providing the hydrophilic parts. The surface tension of these s...

A comprehensive profile of chitin with 61 references is reported. A full description including nomenclature, formulae, elemental analysis, and appearance is included. Methods of preparation for chitin and its derivative, such as chitosan, are discussed. Physical properties, analytical methods, uses and applications, stability, biodegradability, and...

A comprehensive profile of magnesium silicate with 80 references is reported. A full description including nomenclature, formulae, and appearance is included. Methods for magnesium silicate preparation including precipitation, hydrothermal precipitation, and mechanochemical dehydration are reviewed. Physical characteristics, compendia and non-compe...

Bioadhesive buccal films are innovative dosage forms with the ability to adhere to the mucosal surface and subsequently hydrate to release and deliver drugs across the buccal membrane. This study aims to formulate and characterize stable carrageenan (CAR) based buccal films with desirable drug loading capacity. The films were prepared using CAR, po...

Abstract The cyclic di-amino acid peptide N,N′-diacetyl-cyclo(Gly-Gly), C8H10N2O4, crystallizes in the triclinic space group $$ P\bar{1} $$ with unit cell parameters a = 9.4855(4) Å, b = 10.0250(3) Å, c = 10.0763(4) Å, α = 73.682(2)°, β = 82.816(2)°, γ = 81.733(2)°, V = 906.40(6) Å3, Z = 4 (2 molecules, A and B, per asymmetric unit), Dc = 1.452 g c...

There is a paucity of data in respect of the nutritional quality of complementary foods for infants and young children aged between 6 and 12months. The primary objective of this study was to examine nutritive values of such complementary infant food on the UK market in order to ascertain their suitability relative to dietary guidelines for the 6–9m...

The cyclic di-amino acid peptide cyclo(l-homoCySH-l-homoCySH) [(3S, 6S)-3, 6-bis(2-sulfanylethyl) piperazine-2,5-dione, C8H14N2O2S2, crystallizes in the orthorhombic space group P212121 with unit cell parameters a = 6.1509(2) Å, b = 18.0217(9) Å, c = 29.6166(14) Å, V = 3283.0(2) Å3, Z = 12 (3 molecules, A, B and C, per asymmetric unit), D c = 1.422...

The aim of this study was to investigate the differences between the swelling and dissolution properties of solvent cast films and freeze-dried wafers as buccal drug delivery systems. Buccal drug delivery dosage forms have gained increased attention in recent years due to advantages such as bypassing first pass liver metabolism and avoiding GI enzy...

The aim of this study was to develop a freeze-dried wafer to deliver drugs via mucosal surfaces. The advantage of freeze-dried wafers over other mucosal dosage forms is their ability to hydrate in body fluids and maintain drug stability due to milder freeze-drying conditions

Systematic experimental work is required to improve knowledge related to the use of oily delivery systems. This work aimed to examine the influence of different molecular weights chitosan on formation and solubilization ability of w/o system of Labrasol, Plurol Oleique, water and oleic acid. Phase diagrams were constructed. Size measurements were p...

Solid state IR and Raman as well as aqueous solution state Raman spectra are reported for the anions of urazole and 4-methylurazole, and their N-deuterated derivatives. DFT calculations, at the B3-LYP/cc-pVTZ level, established that the structures and vibrational spectra of both anions can be interpreted using a model that incorporates hydrogen-bon...

A directly compressible excipient has been developed by co-processing starch with magnesium silicate. The foregoing was achieved either by co-precipitation of magnesium silicate onto different types of starch or by dry granulation of maize starch with magnesium silicate. A variety of techniques (permeability, water retention/swelling, compression a...

Infrared spectra of the cyclic peptide cyclosporin A and three analogues have been measured in a number of organic solvents (CCl4, CDCl3, acetonitrile, DMSO, and 50:50 acetonitrile: D2O). Seven of the eleven amide groups of cyclosporin A are methylated, the remaining four N-H protons forming strong intramolecular hydrogen bonds in the crystal and i...

Infrared (IR) and Raman spectrawere obtained for N,N�-dicyclohexylcarbodiimide (DCC) in the solid state and in CHCl3 solution. Structures and vibrational spectra of isolated, gas-phase DCC moleculeswith C2 and Ci symmetries, computed at the B3-LYP/ccpVTZ level, show that the IR and Raman spectra provide convincing evidence for a C2 structure in bot...

Back scattered visible Raman spectra of powdered and aqueous solution samples of Victoria Blue B and Victoria blue BO dye molecules show strong fluorescence. The FT-Raman spectral profiles of the two dye molecules, again in the powdered state (examined using an exciting wavelength equal to 1064 nm), are different and vibrational bands have been ass...

Surface enhanced resonance Raman spectroscopy has been used for the semi-quantitative detection of the azo dye Sudan I at ppb levels.

Raman spectroscopy is a potent analytical tool with an extraordinary and increasing number of applications. C.V Raman in 1928 received the Nobel Prize in Physics for this discovery which was eponymously named after him, although the technique was first predicted by A. Smekal in 1923. In the last 35 years the pace of change for this technique has be...