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

Application of SeDeM Expert System in the development of novel directly compressible co-processed excipients via co-processing

Abstract Background Computer-aided formulation design is gaining fantastic attention in chemical engineering of high functionality pharmaceutical materials for dosage form manufacture. To accelerate development of novel formulations in a quality-by-design perspective, SeDeM Expert System preformulation algorithm was developed as a tool for the design of solid drug delivery systems and for prediction of direct compression manufacturability of solid formulations. This research aims to integrate SeDeM Expert System into particle engineering design space of co-processing of solid excipients to develop novel composites with optimum direct compression propensity, using corn starch and microcrystalline cellulose powders as model primary excipients. Result The data and information generated from the expert system have elucidated the bulk-level characteristics of the primary excipients, enabled computation of the optimum co-processing ratio of the ingredients, and validated the impact of co-processing on material functionality. The experimental flowability (7.78±0.17), compressibility functions (5.16±0.14), parameter profile (0.92), and parametric profile index (6.72±0.27) of the engineered composites, were within the acceptable thresholds. With a reliability constant of 0.961, the net direct compression propensity of the composites expressed as Good Compression Index (6.46±0.26) was superior to that of the primary excipients, but comparable to reference co-processed materials, StarLac® (6.44±0.14) and MicroceLac®100 (6.58±0.03). Conclusion Application of SeDeM Expert System in particle engineering via co-processing has provided an accelerated upstream proactive mechanism for designing directly compressible co-processed excipients in a quality-by-design fashion. A four-stage systematic methodology of co-processing of solid excipients was postulated. Stage I entails the characterization of CMAs of both defective and corrective excipients, and elucidation of their physicomechanical limitations using SeDeM diagrams. Stage II involves computation of loading capacity of the corrective excipient using dilution potential equation. Stage III entails the selection of co-processing technique based on desired Critical Material Attributes as revealed by the information obtained from Stage I. Stage IV evaluates the impact of co-processing by monitoring the critical behavior of the engineered composites with a decision on either to accept or reject the product

Evaluacija svojstava vezanja sluzi sjemenki biljke Plantago psyllium

Mucilage extracted from Plantago psyllium seeds was evaluated for inertness and safety parameters. The suitability of psyllium mucilage for a pharmaceutical binder was assessed in paracetamol tablets. Properties of the granules prepared using different concentrations of psyllium mucilage was compared with PVP and tragacanth. Psyllium mucilage at 5 % (m⁄m) level was found to be comparable with 3 % (m⁄m) of PVP. Investigated paracetamol tablets indicated that psyllium mucilage can retard the drug release.U radu je ispitivana neškodljivost i sigurnost uporabe sluzi ekstrahirane iz sjemenki biljke Plantago psyllium. Primjenjivost te sluzi kao veziva u farmaceutskim pripravcima ispitana je na tabletama paracetamola. Granule pripravljene s različitim koncentracijama sluzi uspoređene su s granulama s PVP-om i tragakantom. Sluz s udjelom 5 % (m/m) usporediva je s otopinom PVP-a masenog udjela 3 %. Pripravljene tablete paracetamola ukazuju na to da ispitivana sluz može usporiti oslobađanje lijeka

Letter of intent for KM3NeT 2.0

The main objectives of the KM3NeT Collaboration are ( i ) the discovery and subsequent observation of high-energy neutrino sources in the Universe and ( ii ) the determination of the mass hierarchy of neutrinos. These objectives are strongly motivated by two recent important discoveries, namely: ( 1 ) the high- energy astrophysical neutrino signal reported by IceCube and ( 2 ) the sizable contribution of electron neutrinos to the third neutrino mass eigenstate as reported by Daya Bay, Reno and others. To meet these objectives, the KM3NeT Collaboration plans to build a new Research Infrastructure con- sisting of a network of deep-sea neutrino telescopes in the Mediterranean Sea. A phased and distributed implementation is pursued which maximises the access to regional funds, the availability of human resources and the syner- gistic opportunities for the Earth and sea sciences community. Three suitable deep-sea sites are selected, namely off-shore Toulon ( France ) , Capo Passero ( Sicily, Italy ) and Pylos ( Peloponnese, Greece ) . The infrastructure will consist of three so-called building blocks. A building block comprises 115 strings, each string comprises 18 optical modules and each optical module comprises 31 photo-multiplier tubes. Each building block thus constitutes a three- dimensional array of photo sensors that can be used to detect the Cherenkov light produced by relativistic particles emerging from neutrino interactions. Two building blocks will be sparsely con fi gured to fully explore the IceCube signal with similar instrumented volume, different methodology, improved resolution and complementary fi eld of view, including the galactic plane. One building block will be densely con fi gured to precisely measure atmospheric neutrino oscillations. Original content from this work may be used under the ter

Matrix release from tablets prepared with aqueous dispersion of an acrylate methacrylate (a water – insoluble) copolymer as binder

PURPOSE: To investigate the binder effect of aqueous dispersions of acrylate methacrylates (AMA) copolymer with a view to obtaining matrix (non-disintegrating) tablets with a retard release property. METHODS: Aqueous dispersions of AMA (1-15% w/v) were formed by a coacervation procedure using ethanol (10 ml) as solvent and water (90 ml) as non-solvent for the copolymer. The aqueous dispersions were used to wet–mass the drug (paracetamol) powder. Resulting granules were compressed to 500 mg tablets using a single punch machine. The tablets were subjected to hardness, friability, disintegration and dissolution tests. RESULTS: The granules formed hard tablets (tensile strength 1 - 2.0 MNm-2) with low friability decreasing from 2 to 1 % as the AMA binder concentration increased from 0.75 to 11.25% w/w. The tablets failed to disintegrate in 3 hr. Drug release generally followed the Higuchi square root of time kinetic (R2 0.95). The AMA binder markedly retarded drug release as reflected by the sharp decrease in the dissolution rate constant from 30 min–2 (AMA, 0.75% w/w) to 9 min–2 (AMA, 11.25% w/w). CONCLUSION: The AMA dispersion is an effective binder, producing matrix tablets with a retard release property controlled by the binder content in the tablets. Keywords: Acrylate methacrylate copolymer; Aqueous dispersions; Matrix tablets, Retard release; Friability index; Tensile strength