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Search Results: 1 - 10 of 527 matches for " Ahuja Alka "
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Skin permeation mechanism and bioavailability enhancement of celecoxib from transdermally applied nanoemulsion
Faiyaz Shakeel, Sanjula Baboota, Alka Ahuja, Javed Ali, Sheikh Shafiq
Journal of Nanobiotechnology , 2008, DOI: 10.1186/1477-3155-6-8
Abstract: FTIR spectra and DSC thermogram of skin treated with nanoemulsion indicated that permeation occurred due to the disruption of lipid bilayers by nanoemulsion. The significant decrease in activation energy (2.373 kcal/mol) for celecoxib permeation across rat skin indicated that the stratum corneum lipid bilayers were significantly disrupted (p < 0.05). Photomicrograph of skin sample showed the disruption of lipid bilayers as distinct voids and empty spaces were visible in the epidermal region. The absorption of celecoxib through transdermally applied nanoemulsion and nanoemulsion gel resulted in 3.30 and 2.97 fold increase in bioavailability as compared to oral capsule formulation.Results of skin permeation mechanism and pharmacokinetic studies indicated that the nanoemulsions can be successfully used as potential vehicles for enhancement of skin permeation and bioavailability of poorly soluble drugs.By many estimates up to 90% of new chemical entities (NCEs) discovered by the pharmaceutical industry today and many existing drugs are poorly soluble or lipophilic compounds [1]. The solubility issues obscuring the delivery of these new drugs also affect the delivery of many existing drugs (about 40%). Relative to compounds with high solubility, poor drug solubility often manifests itself in a host of in vivo consequences like decreased bioavailability, increased chance of food effect, more frequent incomplete release from the dosage form and higher intersubject variability. Poorly soluble compounds also present many in vitro formulation development hindrances, such as severely limited choices of delivery technologies and increasingly complex dissolution testing with limited or poor correlation to the in vivo absorption. However, important advances have been made in improving the bioavailability of poorly soluble compounds, so that promising drug candidates need no longer be neglected or have their development hindered by sub optimal formulation. In addition to more conv
Impact Factor : Pros and Cons
Javed Ali,Alka ahuja,Sanjula Baboota,R. K. Khar
Pharmaceutical Reviews , 2003,
Abstract: In recent years the Institute of Scientific Information Journal Citation Reports impact factor has changed from an obscure bibliometric indicator to become the chief quantitative measure of the quality of a journal, its published papers, the scientists who wrote those papers and even the institutes they work within. This article looks at the use and abuse of the impact factor, how it should and should not be used. Introduction The impact factor is o-ne of the three standardized measures created by the Institute of Scientific Information (ISI) which can be used to measure the way a journal receives citations to its articles over time (1,2). These characteristics form the basis of the ISI indicators impact factor, immediacy index and cited half-life. The journal impact factor is a measure of the frequency with which the "average article" in a journal has been cited in a particular year. The impact factor will help you evaluate a journal’s relative importance, especially when you compare it to others in the same field. The impact factor is calculated by dividing the number of current citations to articles published in the two previous years by the total number of articles published in that period. The impact factor is useful in clarifying the significance of absolute (or total) citation frequencies. It eliminates some of the bias of such counts which favour large journals over small o-nes, or frequently issued journals over less frequently issued o-nes, and of older journals over newer o-nes. In the latter case such journals have a larger citable body of literature than smaller or younger journals (3,4).
Formulation and development of targeted retentive device for the treatment of periodontal infections with Amoxycillin trihydrate
Ahuja Alka,Ali J,Shareef A,Khar R
Indian Journal of Pharmaceutical Sciences , 2006,
Abstract: In the present study, an attempt was made to develop a low-dose controlled-release delivery system for the treatment of periodontal infections. Nylon fibres were taken as core material. The coating solution contained polyvinyl acetate and amoxycillin trihydrate. The fibres were coated five times to maximize drug loading. The coating composition was optimized and fibres were subjected to in vitro release studies. For the study, a continuous-flow-through apparatus for in situ drug release, simulating the in vivo conditions of periodontal pocket, was designed in a manner that the drug released was well above the minimum inhibitory concentration of amoxycillin trihydrate. In situ samples were further subjected to microbiological evaluation against the microorganisms which are implicated in periodontal infections. Optimized fibre was further subjected to permeation rate study using modified Franz diffusion cell. The drug-coated fibres provided sustained effect up to a period of 11 d (264 h) and followed first-order release. The drug release followed Fickian diffusion mechanism. In situ samples revealed that the drug level at different time intervals remained above its minimum inhibitory concentration (1.5 μg/ml) for a period of 11 d. In situ release samples when subjected to microbiological evaluation against microorganisms inhibited the growth of S. aureus, S. mutans and B. cereus . Permeation rate studies through bovine cheek pouch membrane revealed that only a low level of drug permeated through the membrane and it followed zero-order permeation rate. The retentive fibres were shown to provide controlled delivery of amoxycillin trihydrate.
Formulation strategy for low absorption window antihypertensive agent
Qureshi M,Ali J,Ahuja Alka,Baboota Sanjula
Indian Journal of Pharmaceutical Sciences , 2007,
Abstract: In the present study a hydrodynamically balanced system of celiprolol hydrochloride was developed as single unit floating capsule. Various grades of low density polymers were used for formulation of this system. They were prepared by physical blending of celiprolol hydrochloride and the polymer in varying ratios. The formulation was optimized on the basis of in vitro buoyancy and in vitro release in citrate phosphate buffer at pH 3.0. Effect of various release modifiers was studied to ensure the delivery of drug from the hydrodynamically balanced system capsule over a period of 12 h. Capsule prepared with HPMC K4 M and liquid paraffin gave the best in vitro percentage release and was taken as optimized formulation. By fitting the data in zero order, first order and Higuchi model it could be concluded that the release followed zero order release, as the correlation coefficient was higher for zero order release. It could be concluded from R 2 value for Higuchi model and K-Peppas model that drug release followed fickian diffusion mechanism.
Pulsatile drug delivery systems: An approach for controlled drug delivery
Arora Shweta,Ali J,Ahuja Alka,Baboota Sanjula
Indian Journal of Pharmaceutical Sciences , 2006,
Abstract: Pulsatile systems are gaining a lot of interest as they deliver the drug at the right site of action at the right time and in the right amount, thus providing spatial and temporal delivery and increasing patient compliance. These systems are designed according to the circadian rhythm of the body. The principle rationale for the use of pulsatile release is for the drugs where a constant drug release, i.e., a zero-order release is not desired. The release of the drug as a pulse after a lag time has to be designed in such a way that a complete and rapid drug release follows the lag time. Various systems like capsular systems, osmotic systems, single- and multiple-unit systems based on the use of soluble or erodible polymer coating and use of rupturable membranes have been dealt with in the article. It summarizes the latest technological developments, formulation parameters, and release profiles of these systems. Products available as once-a-daily formulation based on Pulsatile release like Pulsincap , Ritalin , and Pulsys are also covered in the review. These systems are beneficial for the drugs having chronopharmacological behaviour where night time dosing is required and for the drugs having high first-pass effect and having specific site of absorption in GIT. Drugs used in asthmatic patients and patients suffering from rheumatoid arthritis are also discussed along with many other examples.
Formulation and evaluation of pharmaceutically equivalent parenteral depot suspension of methyl prednisolone acetate
Alam MD.A,Ahuja Alka,Baboota Sanjula,Gidwani S
Indian Journal of Pharmaceutical Sciences , 2009,
Abstract: The aim of the present study was to formulate and evaluate pharmaceutically equivalent injectable aqueous suspension for parenteral depot of methyl prednisolone acetate. Various aqueous suspensions were prepared by rapid stirring and colloid milling method. The prepared aqueous suspensions were subjected to particle size determination, sedimentation study, in vitro release studies (pH dependent dissolution study), and stability studies. The optimized formulation consisted of 4% w/w of methyl prednisolone acetate, 2.91% w/w of PEG-3350, 0.19% w/v of injection grade Tween-80, 0.68% w/w of monobasic sodium phosphate, 0.15% w/w of di-basic sodium phosphate, 0.91% w/v of benzyl alcohol, 0.32% w/w sodium meta bisulphate. The f 2 value was calculated for innovator (DepoMedrol , Batch No. MPH-0254) and optimized formulation at pH 6.8 and pH 7.4 phosphate buffers. The f 2 values of 62.94 and 54.37 were obtained at pH 6.8 and pH 7.4 phosphate buffers respectively. The particle size ranged 23-27 μm at D value of 0.9 for both test and innovator product.
Chronomodulated drug delivery system of salbutamol sulphate for the treatment of nocturnal asthma
Qureshi J,Amir Mohd,Ahuja Alka,Baboota Sanjula
Indian Journal of Pharmaceutical Sciences , 2008,
Abstract: A time dependent pulsed release system consisting of an effervescent core surrounded by consecutive layers of swelling and rupturable polymers was prepared and evaluated. The cores containing salbutamol sulphate as bioactive agent were prepared by direct compression method using different ratios of microcrystalline cellulose and effervescent agent and then coated sequentially with an inner swelling layer containing a hydrocolloid, hydroxypropylmethylcellulose E5 and an outer rupturable layer having Eudragit RL/RS (1:1). The effects of various processing and formulative parameters on the performance of system were studied. The rupture and dissolution tests were studied using the USP paddle method at 50 rpm in 0.1 N HCl and phosphate buffer pH 6.8. The lag time of the drug release decreased by increasing the inner swelling layer and increased by increasing the rupturing layer level. All the results obtained in the present study suggest that osmotic pumping effect was involved which eventually lead to the drug release.
Efficient Algorithms and Data Structures for Massive Data Sets
Alka
Computer Science , 2010,
Abstract: For many algorithmic problems, traditional algorithms that optimise on the number of instructions executed prove expensive on I/Os. Novel and very different design techniques, when applied to these problems, can produce algorithms that are I/O efficient. This thesis adds to the growing chorus of such results. The computational models we use are the external memory model and the W-Stream model. On the external memory model, we obtain the following results. (1) An I/O efficient algorithm for computing minimum spanning trees of graphs that improves on the performance of the best known algorithm. (2) The first external memory version of soft heap, an approximate meldable priority queue. (3) Hard heap, the first meldable external memory priority queue that matches the amortised I/O performance of the known external memory priority queues, while allowing a meld operation at the same amortised cost. (4) I/O efficient exact, approximate and randomised algorithms for the minimum cut problem, which has not been explored before on the external memory model. (5) Some lower and upper bounds on I/Os for interval graphs. On the W-Stream model, we obtain the following results. (1) Algorithms for various tree problems and list ranking that match the performance of the best known algorithms and are easier to implement than them. (2) Pass efficient algorithms for sorting, and the maximal independent set problems, that improve on the best known algorithms. (3) Pass efficient algorithms for the graphs problems of finding vertex-colouring, approximate single source shortest paths, maximal matching, and approximate weighted vertex cover. (4) Lower bounds on passes for list ranking and maximal matching. We propose two variants of the W-Stream model, and design algorithms for the maximal independent set, vertex-colouring, and planar graph single source shortest paths problems on those models.
Regionalization of River Basins Using Cluster Ensemble  [PDF]
Sangeeta Ahuja
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.47065
Abstract: In the wake of global water scarcity, forecasting of water quantity and quality, regionalization of river basins has attracted serious attention of the hydrology researchers. It has become an important area of research to enhance the quality of prediction of yield in river basins. In this paper, we analyzed the data of Godavari basin, and regionalize it using a cluster ensemble method. Cluster Ensemble methods are commonly used to enhance the quality of clustering by combining multiple clustering schemes to produce a more robust scheme delivering similar homogeneous basins. The goal is to identify, analyse and describe hydrologically similar catchments using cluster analysis. Clustering has been done using RCDA cluster ensemble algorithm, which is based on discriminant analysis. The algorithm takes H base clustering schemes each with K clusters, obtained by any clustering method, as input and constructs discriminant function for each one of them. Subsequently, all the data tuples are predicted using H discriminant functions for cluster membership. Tuples with consistent predictions are assigned to the clusters, while tuples with inconsistent predictions are analyzed further and either assigned to clusters or declared as noise. Clustering results of RCDA algorithm have been compared with Best of k-means and Clue cluster ensemble of R software using traditional clustering quality measures. Further, domain knowledge based comparison has also been performed. All the results are encouraging and indicate better regionalization of the Godavari basin data.
Interviewer versus self-administered health-related quality of life questionnaires - Does it matter?
Milo A Puhan, Alka Ahuja, Mark L Van Natta, Lori E Ackatz, Curtis Meinert, the Studies of Ocular Complications of AIDS Research Group
Health and Quality of Life Outcomes , 2011, DOI: 10.1186/1477-7525-9-30
Abstract: We included participants enrolled in the Longitudinal Study of Ocular Complications in AIDS (LSOCA) who completed the Medical Outcome Study [MOS] -HIV questionnaire, the EuroQol, the Feeling Thermometer and the Visual Function Questionnaire (VFQ) 25 every six months thereafter using self- or interviewer-administration. A large print questionnaire was available for participants with visual impairment. Considering all measurements over time and adjusting for patient and study site characteristics we used linear models to compare HRQL scores (all scores from 0-100) between administration formats. We defined adjusted differences of ≥0.2 standard deviations [SD]) to be quantitatively meaningful.We included 2,261 participants (80.6% males) with a median of 43.1 years of age at enrolment who provided data on 23,420 study visits. The self-administered MOS-HIV, Feeling Thermometer and EuroQol were used in 70% of all visits and the VFQ-25 in 80%. For eight domains of the MOS-HIV differences between the interviewer- and self- administered format were < 0.1 SD. Differences in scores were highest for the social and role function domains but the adjusted differences were still < 0.2 SD. There was no quantitatively meaningful difference between administration formats for EuroQol, Feeling Thermometer and VFQ-25 domain scores. For ocular pain (VFQ-25), we found a statistically significant difference of 3.5 (95% CI 0.2, 6.8), which did, however, not exceed 0.2 SD. For all instruments scores were similar for the large and standard print formats with all adjusted differences < 0.2 SD.Our large study provides evidence that administration formats do not have a meaningful effect on repeated measurements of patient-reported outcomes. As a consequence, longitudinal studies may not need to consider the effect of different administration formats in their analyses.Patient-reported outcomes (PRO) are measured in studies using information that is provided directly by study participants. Probably
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