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Gaikwad SS, Zanje AL, Somwanshi JD. Advancements in transdermal drug delivery: A comprehensive review of physical penetration enhancement techniques. Int J Pharm 2024; 652:123856. [PMID: 38281692 DOI: 10.1016/j.ijpharm.2024.123856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/12/2024] [Accepted: 01/24/2024] [Indexed: 01/30/2024]
Abstract
Transdermal drug administration has grown in popularity in the pharmaceutical research community due to its potential to improve drug bioavailability, compliance among patients, and therapeutic effectiveness. To overcome the substantial barrier posed by the stratum corneum (SC) and promote drug absorption within the skin, various physical penetration augmentation approaches have been devised. This review article delves into popular physical penetration augmentation techniques, which include sonophoresis, iontophoresis, magnetophoresis, thermophoresis, needle-free injection, and microneedles (MNs) Sonophoresis is a technique that uses low-frequency ultrasonic waves to break the skin's barrier characteristics, therefore improving drug transport and distribution. In contrast, iontophoresis uses an applied electric current to push charged molecules of drugs inside the skin, effectively enhancing medication absorption. Magnetophoresis uses magnetic fields to drive drug carriers into the dermis, a technology that has shown promise in aiding targeted medication delivery. Thermophoresis is the regulated heating of the skin in order to improve drug absorption, particularly with thermally sensitive drug carriers. Needle-free injection technologies, such as jet injectors (JIs) and microprojection arrays, offer another option by producing temporary small pore sizes in the skin, facilitating painless and effective drug delivery. MNs are a painless, minimally invasive method, easy to self-administration, as well as high drug bioavailability. This study focuses on the underlying processes, current breakthroughs, and limitations connected with all of these approaches, with an emphasis on their applicability in diverse therapeutic areas. Finally, a thorough knowledge of these physical enhancement approaches and their incorporation into pharmaceutical research has the potential to revolutionize drug delivery, providing more efficient and secure treatment choices for a wide range of health-related diseases.
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Affiliation(s)
- Sachin S Gaikwad
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, Savitribai Phule Pune University, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India.
| | - Abhijit L Zanje
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, Savitribai Phule Pune University, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Jeevan D Somwanshi
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, Savitribai Phule Pune University, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
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Gaikwad SS, Kshirsagar SJ. Application of Tablet in Tablet technique to design and characterize immediate and modified release tablets of Timolol maleate. Heliyon 2024; 10:e25820. [PMID: 38356537 PMCID: PMC10865078 DOI: 10.1016/j.heliyon.2024.e25820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 02/01/2024] [Accepted: 02/02/2024] [Indexed: 02/16/2024] Open
Abstract
Hypertension is one of the major causes of mortality in the world. The non-selective -β-blocker which includes Timolol maleate (TM) is usually used in hypertension, at a given dose of 10-40 mg. The present research aims to design a tablet-in-tablet (TIT) formulation as a single-unit dosage form to achieve modified and rapid drug release. Wet granulation was used to create the inner core modified release tablet utilising the release modifying agent's Sodium alginate (SA) and Hydroxypropyl methylcellulose (HPMC K4M). The impact of independent factors, SA and HPMC K4M, in different percentages of w/w, which affect the in vitro drug release and swelling index, was investigated using a 32 complete factorial design. The TM outer instant-release shell, which was made using croscarmellose sodium and Microcrystalline cellulose (MCC) in three distinct sizes, was press-coated onto the optimised inner core tablet. The core and outer shell tablets are within acceptable ranges for several physicochemical properties. No indication of interactions between drugs, polymers, and excipients was found in the Fourier transform infrared (FTIR) and Differential scanning calorimetry (DSC) investigations. The inner core tablet's formulation F6 achieves a 96.38% in vitro drug release at 24 h and a swelling index of 52.7%. The TIT-2 was, however, considered as the final tablet-in-tablet formulation because contains fewer excipients and shorter disintegration time than TIT-3.
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Affiliation(s)
- Sachin S. Gaikwad
- Department of Pharmaceutics, MET's Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India
| | - Sanjay J. Kshirsagar
- Department of Pharmaceutics, MET's Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India
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Gaikwad SS, Morade YY, Kothule AM, Kshirsagar SJ, Laddha UD, Salunkhe KS. Overview of phytosomes in treating cancer: Advancement, challenges, and future outlook. Heliyon 2023; 9:e16561. [PMID: 37260890 PMCID: PMC10227328 DOI: 10.1016/j.heliyon.2023.e16561] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 05/12/2023] [Accepted: 05/19/2023] [Indexed: 06/02/2023] Open
Abstract
One of the major causes of death on the globe is cancer. It has remained a significant obstacle for current therapies and has not yet been effectively treated. Conventional treatment strategies available for cancer such as surgery, chemotherapy, radiation therapy etc. have severe adverse effects. The use of herbal active constituents in cancer treatment has tremendous potential to increase the effectiveness of conventional cancer therapy. Natural plant active components have been reported to have strong in vitro pharmacological activity but narrow in vivo absorption. In order to increase their bioavailability and absorption and get around the drawbacks and negative effects of traditional herbal extracts, Phytosomes are one of the growing nanotechnologies that can be used to improve the miscibility of bioactive phytoconstituents in lipid-rich barriers and overcome their poor bioavailability. Many novel drug delivery carriers are employed for targeted delivery of phytoconstituent at the site of action. Phytosomes are well-known biocompatible nanocarriers that can be employed to increase the solubility and permeability of phytopharmaceuticals among various novel drug delivery systems (NDDS). This review mainly focused on various conventional as well as novel approaches and various Nano carrier used in cancer therapies. Also comprising summary of the most recent research on the development and use of phytosomes as a better carrier for herbal constituents in the treatment of cancer. Additionally provides information about the formulation, characterization technique and mechanism of drug release from phytosome. Some of the major herbal active constituents made of phytosome which have shown proven anticancer activity are also studied. Finally, challenges and future perspective related to phytosome in cancer treatment are also discussed.
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Affiliation(s)
- Sachin S. Gaikwad
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
- Department of Pharmaceutics, MET’s Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India
| | - Yogita Y. Morade
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Akshada M. Kothule
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Sanjay J. Kshirsagar
- Department of Pharmaceutics, MET’s Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India
| | - Umesh D. Laddha
- Department of Pharmaceutics, MET’s Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India
| | - Kishor S. Salunkhe
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
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Gaikwad SS, Kothule AM, Morade YY, Patil SS, Laddha UD, Kshirsagar SJ, Salunkhe KS. An overview of the implementation of SeDeM and SSCD in various formulation developments. Int J Pharm 2023; 635:122699. [PMID: 36764417 DOI: 10.1016/j.ijpharm.2023.122699] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/31/2023] [Accepted: 02/03/2023] [Indexed: 02/10/2023]
Abstract
The Sediment Delivery Model explains experimental analysis and quantitative assessment of the powdered substance characterizing parameters, which offer pertinent data about the material's appropriateness for direct compression (DC) of tablet, which involves mathematical modeling and Semisolid Control Diagram using software like iTCM. The SeDeM diagram expert system (DES) determines the suitability of excipients and active ingredients for DC and the ratio of API to excipient is calculated. The DC is most suitable as it saves time and makes process easy, but these technique excipients compensate for their poor flow. Thus, a new system was required to help reduce number of experiments and time for making an optimized direct compression tablet. The SeDeM DES is based on quality by design (QbD) (ICH Q8) as it evaluates critical quality attributes that affect finished product's quality. This review mainly focuses on various dosage forms like Solid, Semisolid, Liquisolid, and Solidified liquid dosage forms. These techniques mainly characterize all substances using 12 parameters, resulting 12-sided regular polygon. However, parameters may increase or decrease according to the requirement of a particular dosage form like an Orodispersible tablet 15 and a Semisolid dosage form applying 5 parameters. The rationales behind limits for indexes are justified accordingly.
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Affiliation(s)
- Sachin S Gaikwad
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India; Department of Pharmaceutics, MET's Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India.
| | - Akshada M Kothule
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Yogita Y Morade
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Sakshi S Patil
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Umesh D Laddha
- Department of Pharmaceutics, MET's Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India
| | - Sanjay J Kshirsagar
- Department of Pharmaceutics, MET's Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India
| | - Kishor S Salunkhe
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
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Gaikwad SS, Pathare SR, More MA, Waykhinde NA, Laddha UD, Salunkhe KS, Kshirsagar SJ, Patil SS, Ramteke KH. Dry Powder Inhaler with the technical and practical obstacles, and forthcoming platform strategies. J Control Release 2023; 355:292-311. [PMID: 36739908 DOI: 10.1016/j.jconrel.2023.01.083] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/29/2023] [Accepted: 01/30/2023] [Indexed: 02/07/2023]
Abstract
A Dry Powder Inhaler (DPI) is a technique as well as a device used to inhale formulation which is in the form of dry powder, and is inhaled through the nose or mouth. It was developed for the purpose of treating conditions like chronic obstructive pulmonary disease (COPD), Asthma, and even cystic fibrosis etc. The aim of the review is to discuss the different methods of preparation of dry powders along with the characterization of DPI. Here we present the outline of different methods like supercritical fluid extraction (SCF), spray drying, and milling. The review focussed on various devices including single and multi-dose devices used in the DPI. It also highlights on recent advances in the DPI including nano particulate system, siRNA-based medication, liposomes, and pro-liposomes based delivery. In COVID-19 silver nanoparticles-based DPIs provide very prominent results in the infected lungs. Moreover, this review states that the AI-based DPI development provides and improvement in the bioavailability and effectiveness of the drug along with the role of artificial neural networks (ANN). The study also showed that nasally administered drugs (nose to brain) can easily cross the blood-brain barrier (BBB) and enter the central nervous system (CNS) through the olfactory and trigeminal pathway which provides effective CNS concentrations at lower dosage. It is suggested that DPIs not only target respiratory complications but also treat CNS complications too. This review provides support and guides the researcher in the recent development and evaluation of DPI.
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Affiliation(s)
- Sachin S Gaikwad
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India; Department of Pharmaceutics, MET's Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India.
| | - Snehal R Pathare
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Mayur A More
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Nikita A Waykhinde
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Umesh D Laddha
- Department of Pharmaceutics, MET's Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India
| | - Kishor S Salunkhe
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Sanjay J Kshirsagar
- Department of Pharmaceutics, MET's Institute of Pharmacy, Affiliated to Savitribai Phule Pune University, Bhujbal Knowledge City, Adgaon, Nashik 422003, India
| | - Sakshi S Patil
- Department of Pharmaceutics, Sanjivani College of Pharmaceutical Education and Research, At Sahajanandnagar, Post-Shinganapur, Tal-Kopargaon, Dist-Ahmednagar, Maharashtra 423603, India
| | - Kuldeep H Ramteke
- Department of Pharmaceutics, Shivajirao Pawar College of Pharmacy, Pachegaon, Newasa, Ahmednagar Pin: 413725, Affiliated to Dr. Babasaheb Ambedkar Technological University, Lonare, India
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Laddha UD, Sandhan PD, Gaikwad SS, Moravkar KK, Kshirsagar SJ. Fabrication of pioglitazone nanoparticles loaded polymeric dispersion for treatment of dry eye disease with in vitro and in vivo investigation. J Drug Deliv Sci Technol 2023. [DOI: 10.1016/j.jddst.2023.104267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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Abstract
Abstract
Background
Among all available dosage form, tablet is most widely used because of its stability and patient acceptability. The better aesthetic quality like color, texture, mouth feel, and taste masking depended on film and sugar coatings, so the coating is an important part in the formulation of the tablet. The present work aims to comprehensively review the formulation, characterization, and challenges in the development of Tablet in Tablet dosage form.
Main text
Film and sugar coatings have the number of disadvantages; most important one is the utilization of aqueous or organic solvent that leads to toxicity. To overcome this problem in the year 1896, Noyes firstly introduced the compression coating or Tablet in Tablet technique. In the development of Tablet in Tablet dosage form, substantial attention among researchers and various research reports and patents inputs can be found in the literature. Also, we focused on the recent advancements in techniques like one-step dry-coating (OSDrC®) for manufacturing Tablet in Tablet dosage form.
Conclusion
The current review gathered information on the latest patent, formulation, advantages, and disadvantages of Tablet in Tablet or compression coating. The review also elaborates on the importance of Tablet in Tablet techniques in the development of a modified release system.
Graphical abstract
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Abstract
Objective: The main aim of this research work was to develop and evaluate cost effective modified release tablets of Capecitabine (CAP) without utilizing coating techniques.Methods: The tablets were prepared by non-aqueous wet granulation method. Hydroxypropyl cellulose (HPC) was used as an extended release matrix former and sodium alginate (SA) was used as sustained release agent due to its gel forming ability. 32 full factorial design was used to study the effect of the independent variables i.e. HPC and SA on dependent variables, in vitro drug release and swelling index. The physiochemical properties of the drug were analyzed by ultraviolet (UV), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and powder X-ray diffraction (P-XRD). The formulated tablets were evaluated for hardness, thickness, weight variation, content uniformity, swelling index, and in vitro drug release study.Results: The FTIR and DSC studies confirmed that there was no any interaction between drug, polymers and excipients. Also from DSC and P-XRD studies it was clear that the crystalline nature of CAP was remain unchanged in the optimized formulation tablet. Formulation F8 retarded the drug release up to 24 h with the optimum concentration of the both the polymers.Conclusion: We have successfully developed the modified release tablets of CAP with the combination of diffusion and erosion controlled type of drug release mechanism.
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Affiliation(s)
- Sachin S Gaikwad
- Department of Pharmaceutics, SND College of Pharmacy, Nashik, Maharashtra, India
| | - Rohini D Avhad
- Department of Pharmaceutics, Amrutvahini College of Pharmacy, Ahmednagar, Maharashtra, India
| | - Ramesh S Kalkotwar
- Department of Pharmaceutical Chemistry, SND College of Pharmacy, Nashik, Maharashtra, India
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Dhavale VM, Singh SK, Nadeema A, Gaikwad SS, Kurungot S. Correction: Nanocrystalline Fe-Fe 2O 3 particle-deposited N-doped graphene as an activity-modulated Pt-free electrocatalyst for oxygen reduction reaction. Nanoscale 2017; 9:13341-13342. [PMID: 28848949 DOI: 10.1039/c7nr90179h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Correction for 'Nanocrystalline Fe-Fe2O3 particle-deposited N-doped graphene as an activity-modulated Pt-free electrocatalyst for oxygen reduction reaction' by Vishal M. Dhavale et al., Nanoscale, 2015, 7, 20117-20125.
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Affiliation(s)
- Vishal M Dhavale
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411 008, India.
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Gaikwad SS, Avari JG. Effect on Morphology, Osmotic Fragility and Electro Kinetic Potential of Erythrocytes in Hypertension. Curr Hypertens Rev 2017; 13:132-137. [PMID: 28901247 DOI: 10.2174/1573402113666170911140747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/25/2017] [Accepted: 08/26/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND Hypertension is a common health problem concerning a large proportion of population and a leading global risk factor for the burden of cardiovascular disease (CVD). The purpose of this study was to assess the efficacy of the erythrocyte zeta potential as a potential additional indicator for cardiovascular disorder risk so that patients with this can be more rapidly identified and treated. METHODS In the present study, blood samples were collected in 5% dextrose solution from patients suffering from hypertension and healthy volunteers (Not taken any medication). The mobility of individual RBCs was tracked by equipped Zeta meter-ZM4DAQ software using microscopicallyacquired video images, data were recorded 10 times for each sample and average zeta-potential in mv was recorded. RESULTS We found that mean erythrocytic ZP of control group was found to be 23.41 mv (± 1.87) whereas, erythrocytic ZP for Hypertensive patients was found to be 16.05 (±1.72) mV and Hypertensive patients with Diabetes is much lower from 6.96 mV to 22.76 (+3.88) mV along with structural deformities and increased osmotic fragility of erythrocytes. CONCLUSION The data suggest that there are morphological changes in erythrocyte structure, increased osmotic fragility along with significantly lower ZP value as compared to that of healthy volunteers which may be the major cause for progression to the development of cardiovascular disease.
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Affiliation(s)
- S S Gaikwad
- Department of Pharmaceutical Sciences, R. T. M. Nagpur University, Mahatma, Jyotiba Fuley Educational Campus, Amravati Road, Nagpur, 440033, Maharashtra. India
| | - J G Avari
- Department of Pharmaceutical Sciences, R. T. M. Nagpur University, Mahatma, Jyotiba Fuley Educational Campus, Amravati Road, Nagpur, 440033, Maharashtra. India
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Dhavale VM, Singh SK, Nadeema A, Gaikwad SS, Kurungot S. Nanocrystalline Fe-Fe2O3 particle-deposited N-doped graphene as an activity-modulated Pt-free electrocatalyst for oxygen reduction reaction. Nanoscale 2015; 7:20117-20125. [PMID: 26568372 DOI: 10.1039/c5nr04929f] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The size-controlled growth of nanocrystalline Fe-Fe2O3 particles (2-3 nm) and their concomitant dispersion on N-doped graphene (Fe-Fe2O3/NGr) could be attained when the mutually assisted redox reaction between NGr and Fe(3+) ions could be controlled within the aqueous droplets of a water-in-oil emulsion. The synergistic interaction existing between Fe-Fe2O3 and NGr helped the system to narrow down the overpotential for the oxygen reduction reaction (ORR) by bringing a significant positive shift to the reduction onset potential, which is just 15 mV higher than its Pt-counterpart. In addition, the half-wave potential (E1/2) of Fe-Fe2O3/NGr is found to be improved by a considerable amount of 135 mV in comparison to the system formed by dispersing Fe-Fe2O3 nanoparticles on reduced graphene oxide (Fe-Fe2O3/RGO), which indicates the presence of a higher number of active sites in Fe-Fe2O3/NGr. Despite this, the ORR kinetics of Fe-Fe2O3/NGr are found to be shifted significantly to the preferred 4-electron-transfer pathway compared to NGr and Fe-Fe2O3/RGO. Consequently, the H2O2% was found to be reduced by 78.3% for Fe-Fe2O3/NGr (13.0%) in comparison to Fe-Fe2O3/RGO (51.2%) and NGr (41.0%) at -0.30 V (vs. Hg/HgO). This difference in the yield of H2O2 formed between the systems along with the improvements observed in terms of the oxygen reduction onset and E1/2 in the case of Fe-Fe2O3/NGr reveals the activity modulation achieved for the latter is due to the coexistence of factors such as the presence of the mixed valancies of iron nanoparticles, small size and homogeneous distribution of Fe-Fe2O3 nanoparticles and the electronic modifications induced by the doped nitrogen in NGr. A controlled interplay of these factors looks like worked favorably in the case of Fe-Fe2O3/NGr. As a realistic system level validation, Fe-Fe2O3/NGr was employed as the cathode electrode of a single cell in a solid alkaline electrolyte membrane fuel cell (AEMFC). The system could display an open circuit voltage (OCV) of 0.73 V and maximum power and current densities of 54.40 mW cm(-2) and 200 mA cm(-2), respectively, which are comparable to the performance characteristics of a similar system derived by using 40 wt% Pt/C as the cathode electrode.
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Affiliation(s)
- Vishal M Dhavale
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411 008, India.
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Dhavale VM, Gaikwad SS, George L, Devi RN, Kurungot S. Nitrogen-doped graphene interpenetrated 3D Ni-nanocages: efficient and stable water-to-dioxygen electrocatalysts. Nanoscale 2014; 6:13179-87. [PMID: 25255470 DOI: 10.1039/c4nr03578j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Herein, we report the synthesis of a nitrogen-doped graphene (NGr) interpenetrated 3D Ni-nanocage (Ni-NGr) electrocatalyst by a simple water-in-oil (w/o) emulsion technique for oxidation of water to dioxygen. Correlation of adsorption of NGr and subsequent interpenetration through the specific surface plane of nickel particles as well as the concomitant interaction of N and C with Ni in the nano-regime has been investigated. Apart from the benefits of the synergistic interactions between Ni, N, and C, the overall integrity of the structure and its intra-molecular connectivity within the framework help in achieving better oxygen evolution characteristics at a significantly reduced overpotential. The engineered Ni-NGr nanocage displays a substantially low overpotential of ∼290 mV at a practical current density of 20 mA cm(-2) in 0.1 M KOH. In comparison, NGr and Ni-particles as separate entities give overpotentials of ∼570 and ∼370 mV under similar conditions. Moreover, the long term stability of Ni-NGr was investigated by anodic potential cycling for 500 cycles and an 8.5% increment in the overpotential at 20 mA cm(-2) was observed. Additionally, a chronoamperometric test was performed for 15 h at 20 mA cm(-2), which highlights the better sustainability of Ni-NGr under the actual operating conditions. Finally, the quantitative estimation of evolved oxygen was monitored by gas chromatography and was found to be 70 mmol h(-1) g(-1) of oxygen, which is constant in the second cycle as well.
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Affiliation(s)
- Vishal M Dhavale
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune-411 008, India
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Gaikwad SS, Thombre SK, Kale YK, Gondkar SB, Darekar AB. Design andin vitrocharacterization of buccoadhesive tablets of timolol maleate. Drug Dev Ind Pharm 2014; 40:680-90. [DOI: 10.3109/03639045.2014.892955] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Gaikwad SS, Ghate HV, Ghaskadbi SS, Patole MS, Shouche YS. DNA barcoding of nymphalid butterflies (Nymphalidae: Lepidoptera) from Western Ghats of India. Mol Biol Rep 2011; 39:2375-83. [PMID: 21670958 DOI: 10.1007/s11033-011-0988-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 05/28/2011] [Indexed: 11/30/2022]
Abstract
We have checked the utility of DNA barcoding for species identification of nymphalid butterflies from Western Ghats of India by using 650 bp sequence of mitochondrial gene cytochrome c oxidase subunit I. Distinct DNA barcoding gap (i.e. difference between intraspecies and interspecies nucleotide divergence), exists between species studied here. When our sequences were compared with the sequences of the conspecifics submitted from different geographic regions, nine cases of deep intraspecies nucleotide divergences were observed. In spite of this, NJ (Neighbour Joining) clustering analysis successfully discriminated all species. Observed cases of deep intraspecies nucleotide divergences certainly warrant further study.
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Affiliation(s)
- S S Gaikwad
- Department of Zoology, Modern College, Shivajinagar, Pune, 411005 Maharashtra, India
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