Poboljšana topljivost teško topljivog lijeka u čvrstim disperzijama s polimernim i nepolimernim hidrofilnim dodacima

Irbesartan (IBS) is a hydrophobic drug with poor aqueous solubility and dissolution rate. Solid dispersions (SDs) of IBS were prepared with both small molecules (tartaric acid and mannitol) and polymeric additives (polyvinylpyrrolidone, PVP, and hydroxy propyl methylcellulose, HPMC). A 9.5 and 7 folds enhancement in solubility over the crystalline form (14.6 g mL-1) was observed for tartaric acid (138 g mL-1) and PVP (103 g mL-1), respectively. Powder X-ray diffraction confirmed that IBS existed in the glassy state in all cases, even with excipients having low glass transition temperature. Thermal methods (differential scanning calorimetry and hot stage microscopy) were used to evaluate the miscibility of the drug and additives. These techniques suggested that tartaric acid led to generation of ‘amorphous solutions’ in contrast to ‘amorphous suspensions’ in other three cases. The in vitro dissolution of IBS depended on the additive load and increased with increasing concentration in the case of tartaric acid, an acidifying excipient. The results indicate the suitability of even small molecules for providing solubility benefits, which can be attributed to the good glass forming ability and reasonable ability of IBS to remain in the glassy state.Irbesartan (IBS) je hidrofobni lijek teško topljiv u vodi koji se slabo oslobađa iz ljekovitih pripravaka. U radu je opisana priprava čvrstih disperzija (SDs) IBS-a pomoću aditiva male relativne molekulske mase (vinska kiselina i manitol) i polimera (polivinilpirolidona, PVP, i hidroksipropil metilceluloze, HPMC). Koristeći vinsku kiselinu i PVP topljivost je povećana 9,5 puta (138 g mL1), odnosno 7 puta (103 g mL1) u odnosu na kristaliničnu formu (14,6 g mL1). Difrakcijom X-zrakama praškastog uzorka potvrđeno je da je IBS uvijek u staklastom stanju, pa i s pomoćnim tvarima koje pri niskim temperaturama prelaze u staklasto stanje. Termičke metode (diferencijalna pretražna kalorimetrija i mikroskopija s vrućom pločom) korištene su za procjenu sposobnosti miješanja lijeka s aditivima. Rezultati ukazuju da vinska kiselina stvara amorfnu otopinu, a ostale tvari amorfne suspenzije. Oslobađanje IBS-a in vitro ovisi o količini aditiva i raste s povećanjem koncentracije vinske kiseline, (kisele pomoćne tvari). Poboljšanje topljivosti dodatkom malih molekula može se pripisati sposobnosti prelaska IBS-a u staklasto stanje i sposobnosti zadražavanja u tom stanju

Kvalitativna i kvantitativna analiza polimorfa klopidogrel bisulfata

This study deals with characterization and quantification of form I and form II of clopidogrel bisulphate (CLP), a selective and irreversible inhibitor of ADP-induced platelet aggregation. Thermal (DSC, TGA, HSM), crystallographic (XRD) and spectroscopic (FTIR) methods were used for characterization. After characterization of active pharmaceutical ingredient (API), these techniques were further used for identification of the polymorphic form present in three marketed formulations (tablets). FTIR method was successfully developed and validated for the quantification of form I in polymorph mixtures.U radu je opisana karakterizacija i kvantifikacija forme I i forme II klopidogrel bisulfata (CLP), selektivnog i ireverzibilnog inhibitora ADP-inducirane agregacije krvnih pločica. Za karakterizaciju su upotrebljene termičke (DSC, TGA, HSM), kristalografske (XRD) i spektroskopske (FTIR) metode. Nakon karakterizacije aktivne supstancije te metode su dalje upotrebljene za identifikaciju polimorfnih formi u ljekovitim oblicima (tri vrste registriranih tableta). Razvijena je i validirana FTIR metoda za određivanje forme I u smjesi polimorfa

Strategic allocation and energy management of BESS for the provision of ancillary services in active distribution networks

The increased penetration of renewables has prompted the integration of battery energy storage systems (BESSs) in active distribution networks. The BESS not only act as backup power supply but also provides various ancillary services with extra degree of flexibility to distribution networks by changing its' role as generation and load. In this study, a new optimization framework is developed to optimally allocate the intense wind power generation units and BESSs considering its ancillary services in distribution systems. The BESSs are strategically allocated at two sites in coordination with the renewable generating source. One is installed at grid substation to participate in central ancillary services whereas; second will be used to participate in distributed ancillary services. The objective is to minimize the cost of annual energy loss while performing various ancillary services in distribution network. The proposed optimization framework is implemented on a real-life 108-bus Indian distribution system for different cases and solved using genetic algorithm. The comparison of simulation results show that the proposed optimization framework provides more energy loss reduction, improved system voltage and power factor at higher penetration of wind power generation units as compared to the cases in which ancillary services are not considered in planning

Optimal planning of hybrid energy conversion systems for annual energy cost minimization in Indian residential buildings

The increasing interest in renewables has encouraged power system planners to include the concept of hybrid energy systems in modern power industry. Besides, the modern power consumers are becoming more concerned about their energy bills which has led to the concept of hybrid energy management systems (HEMSs) for buildings to monitor, control and optimally manage energy consumptions without any waste. In this study, an optimal planning framework is proposed to determine optimal capacities and sharing of hybrid energy conversion systems (HECS) such as wind turbine, solar photovoltaic, battery energy storage and the utility grid. The objective is to maximize the net present value of the project/system which includes the cost of annual investment, operation and maintenance costs of HEMS expected to have incurred in the planning period. All the costs and parameters are considered in the Indian context, and Genetic Algorithm (GA) is adopted to solve this proposed planning framework. The simulation results obtained are compared with same obtained for conventional houses in India. The comparison shows that the proposed framework effectively reduces the electricity bills while improving its reliability

A single DC source generalized switched capacitors multilevel inverter with minimal component count

This paper presents a new single-source switched capacitor- (SC-) based multilevel inverter (MLI) design with a boosting potential of three times the supply voltage. To produce a waveform with seven output voltage levels, the suggested switching capacitor inverter consists of eight switches, single diode, and two capacitors. Because capacitors are inherently balanced, there is no need for a balancing circuit or sensor. The structure can be expanded using the provided generalized equations. In addition, the technique for switching control and loss analyses is explored. A fair comparison with the most recent SCMLI topologies has been conducted to demonstrate the merits of the proposed work. Furthermore, the proposed topology is evaluated using the MATLAB/SIMULINK tool, and experiments under both transient and steady-state situations are performed to demonstrate its feasibility. At dynamic-loaded situations, the performance of the proposed SCMLI with dynamic modulation index and switching frequency is tested.International Research: SA/China Joint Research Programme.https://www.hindawi.com/journals/iteesElectrical, Electronic and Computer Engineerin

An enhanced space vector PWM strategies for three phase asymmetric multilevel inverter

This work presents the two space vector pulse width modulation (SVPWM-I and SVPWM-II) strategies for eleven-level (11L) asymmetric cascaded H-bridge (CHB) multilevel inverter (MLI). Depending on the isolated structure and nonappearance of capacitor voltage balancing issues, the CHB MLI structure is favoured. These days, the SVPWM control method is accomplished superior consideration among the diverse PWM methods. In common, the SVPWM strategy is realized based on deteriorating higher-level hexagons into a lower level hexagon (2-level). Compared to the classical SVPWM strategy, the proposed SVPWM-I strategy decreases the memory and mathematical burden necessity included within the demonstration of eleven-level SVPWM devoid of losing the inverter output voltage (AC) contour by diminution the number of two-level hexagons. Also, the SVPWM-II strategy is presented, which incredibly diminishes the mathematical endeavours. The presented two SVPWM methods performed on an eleven-level asymmetric CHB multilevel inverter (MLI) by utilizing SIMULINK/MATLAB program tool and are compared with conventional sinusoidal PWM and Third harmonic injection (THI) PWM methods to confirm the proposed SVPWM methods. The proposed SVPWM methods give higher AC RMS voltage and lower harmonic distortion when compared to SPWM and THIPWM methods. To validate the presented two SVPWM control schemes, hardware results are taken on asymmetric eleven-level CHB MLI.https://www.hindawi.com/journals/iteesElectrical, Electronic and Computer Engineerin

Enhancing Biopharmaceutical Attributes of Phospholipid Complex-loaded Nanostructured Lipidic Carriers of Mangiferin: Systematic Development, Characterization and Evaluation

Mangiferin (Mgf), largely expressed out from the leaves and stem bark of Mango, is a potent antioxidant. However, its in vivo activity gets tremendously reduced owing to poor aqueous solubility and inconsistent gastrointestinal absorption, high hepatic first-pass metabolism and high P-gp efflux. The current research work, therefore, was undertaken to overcome the biopharmaceutical hiccups by developing the Mgf-phospholipid complex (PLCs) loaded in nanostructured lipidic carriers (NLCs). The PLCs and NLCs were prepared using refluxing, solvent evaporation and hot emulsification technique, respectively with various molar ratios of Mgf and Phospholipon 90 G, i.e., 1:1; 1:2; and 1:3. The complex was evaluated for various physicochemical parameters like drug content (96.57%), aqueous solubility (25-fold improved) and oil-water partition coefficient (10-fold enhanced). Diverse studies on the prepared complex using FTIR, DSC, PXRD and SEM studies ratified the formation of PLCs at 1:1 ratio. The PLCs were further incorporated onto NLCs, which were systematically optimized employing a face centered cubic design (FCCD), while evaluating for particle size, zeta potential, encapsulation efficiency and in vitro drug release as the CQAs. Caco-2 cell line indicated insignificant cytotoxicity, and P-gp efflux, bi-directional permeability model and in situ perfusion studies specified enhanced intestinal permeation parameters. In vivo pharmacokinetic studies revealed notable increase in the values of Cmax (4.7-fold) and AUC (2.1-fold), respectively, from PLCs-loaded NLCs vis-à-vis Mgf solution. In a nutshell, the promising results observed from the present research work signified boosted biopharmaceutical potential of the optimized PLCs-loaded NLCs for potentially augmenting the therapeutic efficacy of Mgf