Influence of Mucilage Viscosity On The Globule Structure And Stability Of Certain Starch Emulsions

A study was carried out to determine the influence of mucilage viscosity on the globule structure (i.e. size and number) of certain starch emulsions. The starches investigated were cassava, potato and maize. The emulsions were prepared by mixing the starch mucilage of a predetermined concentration 4%w/v with arachis oil in the ratio 50:50, using a silverson mixer fitted with a dispersator head. The emulsions were stored at room temperature (28±20C) for 7 days. Changes in globule size were monitored by photomicroscopy. Viscosities of the mucilage and those of resulting emulsions were determined using a capillary flow method. The viscosities of the emulsions expressed as time of flow (seconds), were 680 (cassava starch), 369 (potato starch) and 270 (Maize starch), and for the mucilage 510 (cassava), 336 (potato) and 248 (maize). The corresponding mean globule sizes of the fresh emulsions were (µm) 28±6, 42±6 and 45±5 respectively. The increase in globule size during storage (measure of globule coalescence rate) was 1.8±0.2µm day -1 (cassava), 3.5±0.2µm day -1 (potato) and 4.6±0.3µm day -1 (maize). Thus, a higher viscosity of the dispersion medium is associated with the production of finer and more stable emulsions

Modeling of drug release from multi-unit dosage tablets of theophylline

A model of multi-unit dose tablets of theophylline (dose, 600 mg) has been designed to give a prompt release dose (200 mg) in the first 1 h and the remaining sustained release dose (400 mg) to be releasedover 11 h at a first order release rate constant of 0.24 h-1. The prompt release component (A) consisted of conventional granules of the drug while the sustained release component (B) was made up of matrixgranules of the drug obtained by melt granulation i.e. granulating the drug powder with a melted wax (carnuba). To form the multi-unit dose tablets, granules of A and B were mixed together in variousproportions in the ratios (A: B) 2:1, 1:1 and 1:2. The disintegration times of the tablets and their dissolution profiles were measured to investigate consistence with the model. The results showed thatthe tablets generally disintegrated readily within 10 min irrespective of the proportion of A to B. Of the various formulations tested, only the formulation consisting of A and B in the ratio 1:1 gave dissolutionprofile that was comparable to that of the model. The following were the dissolution parameters of this formulation: the maximum release (m) = 580 mg, prompt release dose (mp) = 180 mg, time to attainmaximum release (t) = 11 h and first order release rate constant (k1) = 0.27 h-1 which is comparable with the release data for the model. The other formulations deviated by giving mp and t that were either toohigh or too low compared with those of the model. The indication is that the prompt release dose was not determined only by the amount of A in the multi-unit dose formulation but also by the amount of B,attributable to the deformation of granules of A into B during tableting

Effect of matrix granulation and wax coating on the dissolution rates of paracetamol granules

The study was carried out to investigate the release profile of matrix (non-disintegrating) granules consisting of paracetamol (drug) and acrylatemethacrylate copolymer, a matrix forming material. Theeffect of coating the matrix granules with wax on the drug release profiles was also investigated. The objective was to produce drug particles of different release profiles for application as multi-unit dosageforms. The matrix granules were formed by massing paracetamol powder with a concentrated ethanolic solution of the acrylatemethacrylate copolymer (40%, w/v) followed by drying and screening. Waxcoating was achieved by mixing the matrix granules with a melt of carnuba wax. Conventional granules of paracetamol were made by granulation with starch mucilage (20%, w/v); this served as reference samples for comparison. The granules were subjected to size analysis, packing/flow property, friability and dissolution tests. All the granules (i.e. conventional, matrix as well as the coated matrix granules) flowed readily and were also compressible upon tapping. The compressibility index values wereconventional granules (39±2.2%), matrix granules (27±1.8%) and coated matrix granules (24±1.9%). The friability values were conventional granules (1.96±0.02), matrix granules (0.78±0.01) and coated matrixgranules (0.63±0.03), indicating that matrix granulation increased the cohesive strength of the granules. The dissolution rates were conventional granules (16% h-1), matrix granules (9.4% h-1) and coated matrixgranules (4.4% h-1). Thus, matrix granulation and wax coating of the matrix granules are approaches for retarding drug release and hence prolonging the biologic action of drugs with short biologic half liv

Parameters to be Considered in the Simulation of Drug Release from Aspirin Crystals and their Microcapsules

Purpose: Drug microparticles may be microencapsulated with water-insoluble polymers to obtain controlled release, which may be further determined by the particle distribution. The purpose of this study was to determine the drug release parameters needed for the theoretical prediction of the release profiles of single aspirin crystals and their microcapsules. Method: Four single crystals of aspirin of varied weight and orthorhombic in shape or their microcapsules also of varied weights were randomly selected for the study. The microcapsules were walled with an acrylatemethacrylate copolymer (wall thickness, 11 m). The following parameters were evaluated: the order of release, the dissolution rate constant, k (crystals), the diffusion coefficient, D (microcapsules), the maximum release m and time to attain it t. These parameters were in turn used to simulate the release profiles of hypothetical single particles of a wide range size distribution, 0.3 1.4 mm at 0.1mm intervals. Results: The empirical single crystals exhibited an initial zero order (93%; dissolution constant = 4.4 min-1) followed by a first order release (6%; dissolution constant = 0.38 min-1). Maximum release from each of the crystals was 99% of the initial particle weight; thus m was a constant fraction of the initial particle weight. A zero order release consistent with a Fickian diffusion model was displayed by the single microcapsules (diffusion coefficient, 5.4x10-4 mm2min-1). At same particle weight the release parameters m, t, and the slopes of the rate order plots compared favourably with the theoretical data. Conclusion: The study indicates that the empirical release data on a few single particles can be used to predict the release profiles of single particles of a wide range of size distribution. This finding may be exploited in the prediction of drug release from polydisperse systems. Keywords: Aspirin crystals, drug release, simulation, microcapsules Tropical Journal of Pharmaceutical Research 2002; 1(2): 99-11

Human Trafficking and Interface of Slavery In The 21st Century in Nigeria

Trafficking in human beings is modern-day slavery and has become a widespread phenomenon mostly in Africa. Two hundred years after the abolition of the trans-Atlantic slave trade, the trafficking of African children continues unabated. Human trafficking has become a heinous transnational crime undertaken by highly organized syndicates. The syndicates employ deceit, coercion and prey on vulnerable girls whom they traffic overseas for domestic servitude and sexual exploitation. Human trafficking is inherently demeaning, harmful and violates fundamental human rights to life, liberty, dignity and freedom from discrimination. This work therefore, examines all forms of human trafficking in Nigeria, revealing the operations of the trafficking business and the nature of the traffickers themselves. Using a historical and comparative perspective between human trafficking and slavery, it then demonstrates that there is great correspondence that exists between the two phenomenons. Necessary recommendations were also given to eradicate human trafficking and other related transnational crimes in Nigeria. Keywords: Human Trafficking, Child Labour, Slavery, Nigeria

Effect of acid treatment on the consolidation and plasto-elasticity of tapioca powder

Purpose: The effects of treating the tapioca (the fibrous residue obtained after up to 90% of the proportion of starch has been removed from the peeled and rasped roots of cassava tubers powder with dilute solutions of hydrochloric acid) in order to find an approach for rendering an otherwise poorly compressible material to a directly compressible powder. Method: The parameters measured were the degree of consolidation of the powder after compression (i.e. the packing fraction of resulting tablets), the plasto-elasticity of the powders as reflected by the brittle fracture index (BFI) of the tablets made from the powders and the viscosities of mucilages derived from the powders. The influence of time of exposure and the concentration of acid used in the treatment were studied. Results: The degree of consolidation of the powder increased slightly with increase in duration of exposure to acid (24 — 72 h) but drastically with increase in the acid concentration from 0.1 to 0.4 mol. L—1. On the other hand, the plasto-elasticity of the powders as measured by the BFI values and the viscosities of mucilages derived from the powders decreased slightly with duration of exposure but drastically with increase in acid concentration. A change in acid concentration was therefore the more determinant factor with regards to the consolidation and plasto-elasticity properties of the powders. The decrease in the viscosities of the mucilages following acid treatment of the powders was indicative of a breakdown of polymeric structure in the powder Conclusion: Acid treatment of tapioca powder imparted plasticity in tapioca powder which became compressible. Key words: Plasto-elasticity, brittle fracture index, tapioca powder. Trop J Pharm Res, June 2002; 1(1): 45-4

Limitation observed in the application of the three dimensional solubility parameters to the coating formulation of poly (3-hydroxybutyrate-hydroxyvalerate) systems

Purpose: Poly (3-hydroxybutyrate-hydroxyvalerate) displayed high dipole-dipole interaction, a high hydrogen bonding but low polar interaction, and was therefore expected to be miscible with solvents/plasticizers that exhibit similar pattern of cohesive interaction. To determine the applicability, or otherwise of the theory of the three dimensional solubility parameters to the formulation of poly (3-hydroxybutyrate-hydroxyvalerate) polymeric coating system, and hence identify any limitation in the application of the theory. This aspect was investigated in the study. Method: The structural group contribution method was employed to compute the partial and total solubility parameters of the compounds – the biopol polymer, a series of organic solvents and plasticizers. The computed partial solubility parameters included: dipole-dipole (dd), polar (dp) and hydrogen bonding (dh). Following a standard procedure in the literatures, the dd and dp values were combined to form a composite solubility parameter, dv: where dv = &#8730 &#948d 2+&#948p 2. A plot of dh versus dv gave the energy maps, which depicted the energy levels of the various compounds and from which the miscibility of the compounds were predicted. The closer the position of the solvent or plasticizer to the polymer in the map, the greater, the probability of mixing. Cast films of the various polymeric formulations were made and examined for homogeneity by scanning electron microscopy. Results: It was possible to select suitable plasticizers that were miscible with the polymer by applying theory of solubility parameters. The prediction for the solvents was, however, erroneous and this may be attributable to the inability of the dv parameter to clearly reflect the differences between the dd and dp interactions of the polymer on the one hand and those of the various solvents in all situations on the other hand. This means that in certain instances, the dv values of the polymer and the solvents were similar even though their dd and dp interactions were dissimilar. Conclusion: The analysis of the data showed that the composite solubility parameter dv of compounds could be similar even though the actual energies of dd and dp interactions are different. This is a limitation in the application of the theory of the three dimensional solubility parameters. Keywords: keyword; keyword; keyword > Tropical Journal of Pharmaceutical Research Vol. 4 (1) 2005: pp. 355-36

Influence of some starch binders on the brittle fracture tendency of paracetamol tablets

The study was carried out to compare the binder effects of cassava and cocoyam starch with that of maize starch BP. The parameters investigated were the brittle fracture index (BFI), the tablet packingfraction (Pf), and tensile strength (T). Mucilages of the starches of varying concentrations; 15, 20, and 25% (w/v) were formed; their viscosities were determined and used to form paracetamol granules bywet-massing. The granules were compressed at different compression loads (arbitrary units on the load scale; 8, 9 and 9.5). At all given compression loads and at all binder concentration, cassava starchmucilages binder produced the hardest and most compact tablets with the least tendency to brittle fracture compared with cocoyam or maize starch mucilage. For instance, the BFI values at the compression load, 8 were 0.13 (tablets formed with cassava starch mucilage 20% w/v) 0.18 (tablets formed with cocoyam starch mucilage 20% w/v) and 0.35 (tablets formed with maize starch mucilage 20% w/v). Increase in compression load (8 to 9.5) increased the BFI of these tablets while an increase in binder concentration generally caused a decrease in BFI of these tablets. This decrease was less marked at higher compression load. The results indicate that cassava starch mucilage which was themost viscous, displayed the highest potential for ameliorating brittle fracture during manufacture of paracetamol tablets

Current trends in the production and biomedical applications of liposomes: a review

A review of literature was carried out to determine methods of production of liposomes, their stability, biodistribution and their uses as drug delivery systems. The conventional method of preparing liposomes is basically for the multilamellar vesicles (MLVs). However, other methods are used to reduce the size of these MLVs to small unilamellar vesicles (SUVs) so as to increase their plasma lifetime and consequently increase the possibility of achieving greater tissue localisation. Some of these methods of size reduction are sonication and high pressure extrusion. Each of these methods has its own advantages and disadvantages. Large unilamellar vesicles (LUVs), on the other hand, are prepared mainly by detergent removal method and reverse phase extrusion technique. There are also improved pharmacokinetic properties with liposomal drugs compared to free drugs, though some formulation factors affect the release kinetics of the liposomal drugs. The review also shows that liposomes have a lot of biomedical applications and uses. They have been used in drug targeting, oral delivery of vaccines, insulins, peptides and some compounds, which are usually degraded in the gastrointestinal tract. It has also found application in topical therapy especially in the eye and lungs. Other areas of application are in cancer chemotherapy and treatment of human immunovirus (HIV) infection. The control of the stability of liposomes is an essential pre-requisite for effective use as drug carriers. Leakage of the liposome is attributable mainly to differences in lamellar structure. For instance, MLVs are less prone to leakage than ULVs. The use of a combination of saturated phospholipid and cholesterol in the formulation of the liposomes has also been found to enhance stability with lower tendency to leakage

Relationship Between Slugging Pressure and Brittle Fracture Tendency – A Case Study for Aspirin Tablets

Objective – Slugging is a pre-compression technique for the dry granulation of hydrolysable drugs (e.g. aspirin). The study was carried out to relate the slugging load to the hardness of the granules and the brittle fracture tendency of the final (recompressed) tablets. Method – Varying compression load were applied to aspirin powder to form slugs, which were subsequently broken down to form granules. These were recompressed to give the final tablets. The hardness of the slugs was determined and taken as measure of the hardness of the resulting granules. The following tableting parameters were measured for the final tablets - tensile strength (T), packing fraction (Pf) and the brittle fracture index (BFI). Results - A high slugging load was associated with the formation of hard slugs and hence hard granules. Upon recompression the hardest granules formed the hardest tablets (T = 3.29MN m-2) while the softest granules formed the softest tablets (T=1.09MN m-2). In turn, the hardest tablets displayed the highest brittle fracture tendency (BFI = 0.59) compared with the softest tablets (BFI= 0.21). A positive linear correlation existed between tablet hardness (T) and BFI values (r = 0.98). Keywords: Slugging pressure, aspirin granules, tablet tensile strength, brittle fracture index > Tropical Journal of Pharmaceutical Research Vol. 4 (2) 2005: pp. 483-48