Showing papers by "Government College published in 2009"

Trimethyl chitosan and its applications in drug delivery.

Abstract: Chitosan, a polymer obtained by deacetylation of chitin is widely studied for its pharmaceutical and nonpharmaceutical applications. Recommendations about uses of this polymer although could not be always realized due to limited solubility. Chitosan, for example, has been extensively evaluated for its mucoadhesive and absorption enhancement properties. The positive charge on the chitosan molecule gained by acidic environment in which it is soluble seems to be important for absorption enhancement. However chitosan is not soluble in medium except below pH 5.6. This limits its use as permeation enhancer in body compartments where pH is high. In this regard there is a need for chitosan derivatives with increased solubility, especially at neutral and basic pH values. Trimethylation of chitosan is an effort in this direction. Despite the abundance of the research related to trimethyl chitosan (TMC), the overview of the topic is not available. Hence an attempt is made in this review to cover the recent findings pertaining to synthesis, characterization and applications of TMC especially in pharmaceutical field. TMC has been synthesized by different ways and characterized by FTIR, NMR, DSC etc. This quaternized derivative of chitosan possesses a positive charge and is soluble over a wide range of pH. TMC, being a derivative of cationic polymer enriched with positive charge shows better mucoadhesive, permeation enhancement, drug delivery and DNA delivery properties. TMC can be further derivitized or grafted for modulating properties as solubility, cytotoxicity or cell recognition ability. Apart from these applications, TMC itself and its derivatives exhibit antimicrobial properties also. Quaternization of chitosan not only with methyl group but higher group as ethyl or along with spacer or quaternization of modified chitosan can be of interest too.

Co-crystals: a novel approach to modify physicochemical properties of active pharmaceutical ingredients.

Abstract: Crystal form can be crucial to the performance of a dosage form. This is especially true for compounds that have intrinsic barriers to drug delivery, such as low aqueous solubility, slow dissolution in gastrointestinal media, low permeability and first-pass metabolism. The nature of the physical form and formulation tends to exhibit the greatest effect on bioavailability parameters of water insoluble compounds that need to be given orally in high doses. An alternative approach available for the enhancement of drug solubility, dissolution and bioavailability is through the application of crystal engineering of co-crystals. The physicochemical properties of the active pharmaceutical ingredients and the bulk material properties can be modified, whilst maintaining the intrinsic activity of the drug molecule. This article covers the advantages of co-crystals over salts, solvates (hydrates), solid dispersions and polymorphs, mechanism of formation of co-crystals, methods of preparation of co-crystals and application of co-crystals to modify physicochemical characteristics of active pharmaceutical ingredients along with the case studies. The intellectual property implications of creating co-crystals are also highly relevant.

Physicochemical characterization of solid dispersion systems of tadalafil with poloxamer 407.

Abstract: Dissolution behaviour of a poorly water-soluble drug, tadalafil, from its solid dispersion systems with poloxamer 407 has been investigated. Solid dispersion systems of tadalafil were prepared with poloxamer 407 in 1:0.5, 1:1.5 and 1:2.5 ratios using the melting method. Characterization of binary systems with FTIR and XRPD studies demonstrated the presence of strong hydrogen bonding interactions, a significant decrease in crystallinity and the possibility of existence of amorphous entities of the drug. In the binary systems tested, 1:0.5 proportion of tadalafil/poloxamer 407 showed rapid dissolution of tadalafil (DE(30) 70.9 + or - 3.6 %). In contrast, higher proportions of poloxamer 407 (1:1.5 and 1:2.5) offered no advantage towards dissolution enhancement of the drug, indicating altered rheological characteristics of the polymer at its higher concentration, which might have retarded the release rate of tadalafil.

Copper K-edge XANES of Cu(I) and Cu(II) oxide mixtures

Abstract: XAFS at the copper K-edge has been recorded for cuprous oxide and cupric oxide separately and also for a mixture of the two in a specific ratio, at the XAFS beam line at SSRL. The normalized μ(E) data obtained for the two oxides, i.e., Cu(I) and Cu(II) oxides separately was linearly combined to fit the normalized μ(E) data of the mixture using the Linear Combination Fitting (LCF) method. The values obtained for the statistical goodness-of-fit parameters, R-factor and chi-square, show that the fit is reasonably good. This procedure yielded the percentage of the oxides in the mixture which was found to be nearly the same as the actual percentage which was used to prepare the mixture. Another method based on the analysis of normalized difference absorption edge spectra has also been used to quantitatively determine the percentage of the two copper species in the mixture. The LCF method is, however, found to be better than the normalized difference absorption edge analysis.

A hyperbolic shear deformation theory for flexure and vibration of thick isotropic beams

Abstract: A Hyperbolic Shear Deformation Theory taking into account transverse shear deformation effects, is presented for the static flexure and free flexural vibration analysis of thick isotropic beams. The displacement field of the theory contains two variables and does not require shear correction factor. The hyperbolic sine function is used in the displacement field in terms of thickness coordinate to represent shear deformation. The most important feature of the theory is that the transverse shear stress can be obtained directly from the use of constitutive relation, satisfying the stress free boundary conditions at top and bottom of the beam. Hence, the theory obviates the need of shear correction factor. Governing differential equations and boundary conditions of the theory are obtained using the principle of virtual work. Results obtained for flexure and free vibration of simply supported uniform, isotropic beams are compared with those of elementary, refined, and exact beam theories to validate the accuracy of the theory.

Structural and thermal properties of PVDF/PVA blends

Abstract: Thermal properties such as thermal diffusivity and thermal conductivity are measured by photoacoustics at room temperature for various particle sizes, thicknesses and the percentage of mixing of poly (vinyl alcohol) (PVA) in Poly (vinylidene fluoride) (PVDF)/PVA blends. The results are compared with other experimental reports, which is by laser flash technique for various temperatures. The agreement is very good at room temperature; in our study, it is 0.20 Wm−1 K−1, whereas by laser flash technique it is 0.18 Wm−1 K−1 for thermal conductivity. The importance of dislocation density and strain is discussed.

Formulation and evaluation of in situ gelling thermoreversible mucoadhesive gel of fluconazole.

Abstract: The purpose of the present study was to develop ophthalmic gel formulations of fluconazole. Intraocular delivery of topically applied drugs such as fluconazole is hampered by elimination of the solution due to tear turnover, so an in situ gelling thermoreversible mucoadhesive gel was formulated. Thermoreversible mucoadhesive gels were prepared using the cold method along with poloxamer 407 and different mucoadhesive polymers such as hydroxy ethyl cellulose (HEC), hydroxy propyl methyl cellulose (HPMC) K4M, and polyvinyl pyrrolidone (PVP) K30. Gels were evaluated for physical parameters like appearance, gelation temperature, pH, spreadability, drug content, gel strength, bioadhesion, and in vitro permeation. A modified device (modified K-C diffusion cell with a sheep's eye corneal membrane as a diffusion membrane) was used for evaluation of drug permeation through a sheep's corneal membrane. The formulated gels were transparent, uniform in consistency, and had spreadability with a pH range of 6.8 to 7.3. Satisfactory bioadhesion on the sheep's corneal surface and good gel strength were also observed. Diffusion studies have shown that a matrix is the best-fit model. As the concentration of mucoadhesive agent increases, the rate of permeation decreases. The order of drug permeation through the membrane was HEC > PVP K30 > HPMC K4M. This study found that a thermoreversib le polymer and mucoadhesive polymers can be effectively used to prolong residence time.

Determination of Montelukast Sodium and Bambuterol Hydrochloride in Tablets using RP HPLC.

Abstract: An accurate, specific and precise assay level gradient reverse-phase high-performance liquid chromatographic method was developed for simultaneous determination of montelukast sodium and bambuterol hydrochloride in tablet dosage form. An inertsil ODS C-18, 5 µm column having 250×4.6 mm I.D. in gradient mode, with mobile phase A, containing 0.025 M sodium phosphate buffer: methanol (85:15) and mobile phase B, containing acetonitrile:methanol (85:15) was used at different time intervals. The flow rate was 1.5 ml/min and effluent was monitored at 218 nm. The retention times of montelukast sodium and bambuterol hydrochloride were 21.2 min and 5.8 min respectively. The linearity for both the drugs was in the range of 0.25-0.75 mg/ml with correlation coefficients of 0.9999 and 0.9996 for montelukast sodium and bambuterol hydrochloride, respectively.

Trilinearization and localized coherent structures and periodic solutions for the (2 + 1) dimensional K-dV and NNV equations

Abstract: In this paper, using a novel approach involving the truncated Laurent expansion in the Painleve analysis of the (2 + 1) dimensional K-dV equation, we have trilinearized the evolution equation and obtained rather general classes of solutions in terms of arbitrary functions. The highlight of this method is that it allows us to construct generalized periodic structures corresponding to different manifolds in terms of Jacobian elliptic functions, and the exponentially decaying dromions turn out to be special cases of these solutions. We have also constructed multi-elliptic function solutions and multi-dromions and analysed their interactions. The analysis is also extended to the case of generalized Nizhnik–Novikov–Veselov (NNV) equation, which is also trilinearized and general class of solutions obtained.

Hepatoprotective activity of hydroalcoholic extract of leaves of Alocasia indica (Linn.)

Abstract: Oral administration of hydroalcoholic extract of A. indica (250 and 500 mg/kg) effectively inhibited CCl4 and paracetamol induced changes in the serum marker enzymes, cholesterol, serum protein and albumin in a dose-dependent manner as compared to the normal and the standard drug silymarin-treated groups. Hepatic steatosis, fatty infiltration, hydropic degeneration and necrosis observed in CCl4 and paracetamol-treated groups were completely absent in histology of the liver sections of the animals treated with the extracts. The results suggests that the hydroalcoholic extract of leaves of A. indica possess significant potential as hepatoprotective agent.

Acoustic and Thermodynamic Properties of Binary Liquid Mixtures of Benzaldehyde in Hexane and Cyclohexane

Abstract: Densities and ultrasonic speeds of binary mixtures of benzaldehyde with n-hexane and cyclohexane at 30 °C were measured over the entire composition range. From these experimental data, the adiabatic compressibility (K S ), intermolecular free length (L f), acoustic impedance (Z), relative association (R a) and relaxation strength (r) were calculated. Also, the excess adiabatic compressibility (K E ), intermolecular free length (L f E ), acoustic impedance (Z E), and ultrasonic velocity (U E) were calculated. The observed variation of these parameters helps in understanding the nature of interactions in these mixtures. Further, theoretical values of the ultrasonic speed were evaluated using theories and empirical relations. The relative merits of these theories and relations were discussed.

Synthesis and characterization of palladium(II) complexes of thioureas. X-ray structures of [Pd(N,N′-dimethylthiourea)4]Cl2 · 2H2O and [Pd(tetramethylthiourea)4]Cl2

Abstract: Palladium(II) complexes of thiones having the general formula [Pd(L)4]Cl2, where L = thiourea (Tu), methylthiourea (Metu), N,N′-dimethylthiourea (Dmtu), and tetramethylthiourea (Tmtu) were prepared by reacting K2[PdCl4] with the corresponding thiones. The complexes have been characterized by elemental analysis, IR and NMR spectroscopy, and two of these, [Pd(Dmtu)4]Cl2 · 2H2O (1) and [Pd(Tmtu)4]Cl2 (2), by X-ray crystallography. An upfield shift in the >C=S resonance of thiones in 13C NMR and downfield shift in N–H resonance in 1H NMR are consistent in showing sulfur coordination with palladium(II). The crystal structures of the complexes show a square-planar coordination environment around the Pd(II) ions with the average cis and trans S–Pd–S bond angles of 89.64° and 173.48°, respectively.

Auxin Analogues and Nitrogen Metabolism, Photosynthesis, and Yield of Chickpea

Abstract: The impact of three auxins indole-3-acetic acid (IAA), 4-chloroindole-3-acetic acid (4-Cl-IAA), and indole-3-butyric acid (IBA) on nitrogen metabolism were investigated in chickpea (Cicer arietinum L.). Plants were raised from seeds soaked in water (control), 10−8 M of IAA, IBA, or 4-Cl-IAA, for 12 hours and were assessed for different parameters at 60 days after sowing. Observations showed that auxins, irrespective of the analogue significantly increased the nodulation, leghemoglobin content, nodule nitrogen content and the enzymes of nitrogen assimilation. Of the three auxins, 4-Cl-IAA was the most effective in increasing these parameters. The increase in seed yield was 27% higher than the water soaked control. The response to auxins followed the trend 4-Cl-IAA > IAA > IBA > control. It may be concluded from the present investigation that auxins, irrespective of the type, significantly improved the nitrogen metabolism, photosynthesis and yield of the chickpea. Of three auxins used, 4-Cl-IAA gen...

Assessing the Performance of Secondary School Headteachers A Survey Study Based on Teachers’ Views in Punjab

Abstract: This article focuses on assessing the performance of government secondary school headteachers in the context of heads’ leadership qualities, instructional behavior, capabilities of interpersonal relationships, professional attitude and managerial abilities. The small-scale survey was carried out in 2006 in district Mianwali, Pakistan. The sample comprised 150 secondary school teachers drawn at random from 15 government schools. Data was collected through a questionnaire comprising 38 items on a five-point rating scale on various aspects of headteacher performance. The instrument was validated through a pilot study and its reliability was established at 0.901 (Cronbach’s alpha). Results revealed that the performance indicators of professional attitude, interpersonal relationship, leadership qualities and managerial abilities were found to be better, but the aspect of instructional behavior was weaker among the headteachers. The performance of female headteachers in regard to instructional behavior, profess...

The collision of multimode dromions and a firewall in the two-component long-wave–short-wave resonance interaction equation

Abstract: In this communication, we investigate the two-component long-wave‐shortwave resonance interaction equation and show that it admits the Painlev´ e property. We then suitably exploit the recently developed truncated Painlev´ e

High Q Microwave Dielectric Ceramics in (Ni1−x Znx)Nb2O6 System

Abstract: (Ni1−xZnx)Nb2O6, 0≤x≤10, ceramics with >97% density were prepared by a conventional solid-state reaction, followed by sintering at 1200°–1300°C (depending on the value of x) The XRD patterns of the sintered samples (0≤x≤10) revealed single-phase formation with a columbite (Pbcn) structure The unit cell volume slightly increased with increasing Zn content (x) All the compositions showed high electrical resistivity (ρdc=16±03 × 1011Ω·cm) The microwave (4–5 GHz) dielectric properties of (Ni1−xZnx)Nb2O6 ceramics exhibited a significant dependence on the Zn content and to some extent on the morphology of the grains As x was increased from 0 to 1, the average grain size monotonically increased from 76 to 212 μm and the microwave dielectric constant (ɛ′r) increased from 236 to 261, while the quality factors (Qu×f) increased from 18 900 to 103 730 GHz and the temperature coefficient of resonant frequency (τf) increased from −62 to −73 ppm/°C In the present work, we report the highest observed values of Qu×f=103 730 GHz, and ɛ′r=261 for the ZnNb2O6-sintered ceramics

Physicochemical investigation of the solid dispersion systems of etoricoxib with poloxamer 188.

Abstract: Solid dispersion systems of a poorly water-soluble drug, etoricoxib were prepared with poloxamer 188 in 1:0.5, 1:1.5 and 1:2.5 ratios and evaluated by FTIR, powder XRD and dissolution studies. Physical studies demonstrated a strong hydrogen bonding with significant decrease in the crystallinity and formation of amorphous etoricoxib in its binary systems. All binary systems of etoricoxib showed faster dissolution than pure drug alone (P < 0.001). However, 1:2.5 proportion of etoricoxib: poloxamer 188 showed superior performance (DE45: 71.27% ± 3.85) in enhancing solubility and dissolution rate of etoricoxib suggesting optimum ratio of the carrier.

Preparation and physicochemical characterization of surfactant based solid dispersions of ezetimibe.

Abstract: Solid dispersions of the poorly water-soluble drug ezetimibe were prepared with a surfactant, Pluronic® 188 in different ratios and characterized by FTIR, XRD, DSC and dissolution studies The melting method was employed to prepare the solid dispersions whereas a physical mixture (1:3) was prepared by co-grinding the individual components in a mortar Physical studies demonstrated a significant reduction in crystallinity with a possibility of presence of amorphous character of drug in the solid dispersions of ezetimibe Among all binary systems studied, the 1:3 proportion of ezetimibe: Pluronic® 188 showed fastest dissolution rate (DE 90 : 7338% ± 395) suggesting optimum ratio of the surfactant used

Study on the Participation of Women in Panchayati Raj Institution

Abstract: Panchyati Raj Institutions have always been considered as a means to good governance and 73rd Constitutional Amendment was effected in the hope that it would lead to better governance and provide p...

Application of D-STATCOM to mitigate voltage sag due to DOL starting of three phase induction motor

Abstract: A mathematical model of Distribution STATCOM has been implemented in MATLAB/Simulink to validate its capability for mitigation of voltage sag due to DOL starting of induction motor. This paper organized with brief introduction to voltage sag problem followed by characteristics of voltage sag, basic structure & operation of D-STATCOM. The model is subjected to, first without D-STATCOM and then with it. The results obtained in both the cases are analyzed. Based on this analysis the capability of D-STATCOM to mitigate the voltage sag due to DOL starting of IM is validated.