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Rambharose S, Kalhapure RS, Jadhav M, Govender T. Novel mono, di and tri-fatty acid esters bearing secondary amino acid ester head groups as transdermal permeation enhancers. NEW J CHEM 2018. [DOI: 10.1039/c7nj04025c] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mono-oleate derivative (MOAPE) enhancing in vitro transdermal permeation of tenofovir.
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Affiliation(s)
- S. Rambharose
- Department of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - R. S. Kalhapure
- Department of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - M. Jadhav
- Department of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - T. Govender
- Department of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
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52
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Kalhapure RS, Sikwal DR, Rambharose S, Mocktar C, Singh S, Bester L, Oh JK, Renukuntla J, Govender T. Enhancing targeted antibiotic therapy via pH responsive solid lipid nanoparticles from an acid cleavable lipid. Nanomedicine: Nanotechnology, Biology and Medicine 2017; 13:2067-2077. [DOI: 10.1016/j.nano.2017.04.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 04/01/2017] [Accepted: 04/11/2017] [Indexed: 02/07/2023]
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53
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Mhango EKG, Kalhapure RS, Jadhav M, Sonawane SJ, Mocktar C, Vepuri S, Soliman M, Govender T. Preparation and Optimization of Meropenem-Loaded Solid Lipid Nanoparticles: In Vitro Evaluation and Molecular Modeling. AAPS PharmSciTech 2017; 18:2011-2025. [PMID: 27933586 DOI: 10.1208/s12249-016-0675-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 11/18/2016] [Indexed: 12/20/2022] Open
Abstract
Encapsulation of antibiotics into nanocarriers has the potential to overcome resistance and disadvantages associated with conventional dosage forms as well as increase half-life of an antibiotic. Encapsulation of meropenem (MRPN) into solid lipid nanoparticles (SLNs) remains unexplored among the limited work reported on nanoformulation incorporating MRPN. The study aimed to use an experimental design, to optimize MRPN-loaded SLNs, and to undertake in vitro and in silico evaluations. A Box-Behnken design (BBD) was used to optimize manufacturing conditions of glycerol monostearate (GMS) SLNs loaded with MRPN. The SLNs were prepared using hot homogenization and ultrasonication method. Optimized MRPN-SLNs showed particle size, zeta potential, and entrapment efficiency of 112.61 ± 0.66 nm, -20.43 ± 0.99 mV, and 89.94 ± 1.26%, respectively. The morphology of the SLNs revealed nearly spherical shaped particles. Differential scanning calorimetry and X-ray diffraction analysis showed that meropenem was present in amorphous form in the SLNs. Controlled in vitro MRPN release from SLNs was achieved and followed the Korsmeyer-Peppas model (R 2 = 0.9679). Prolonged in vitro antibacterial activity against Escherichia coli was also observed. The molecular modeling showed that both hydrophobic interactions and hydrogen bonding led to a stable MRPN-GMS complex formation, which was confirmed by its low heat of formation (-5536.13 kcal/mol). This stable complex could have contributed to the controlled release of MRPN from the SLNs and subsequent sustained antibacterial activity.
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Govender T, Reddy P, Ghuman S. Obstetric outcomes and antenatal access among adolescent pregnancies in KwaZulu-Natal, South Africa. S Afr Fam Pract (2004) 2017. [DOI: 10.1080/20786190.2017.1333783] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- T Govender
- Department of Community Health Studies, Discipline of Environmental Health, Durban University of Technology, Durban, South Africa
| | - P Reddy
- Department of Community Health Studies, Discipline of Environmental Health, Durban University of Technology, Durban, South Africa
| | - S Ghuman
- Department of Community Health Studies, Discipline of Environmental Health, Durban University of Technology, Durban, South Africa
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55
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Sanusi ZK, Govender T, Maguire GEM, Maseko SB, Lin J, Kruger HG, Honarparvar B. Investigation of the binding free energies of FDA approved drugs against subtype B and C-SA HIV PR: ONIOM approach. J Mol Graph Model 2017; 76:77-85. [PMID: 28711760 DOI: 10.1016/j.jmgm.2017.06.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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: 04/01/2017] [Revised: 06/08/2017] [Accepted: 06/09/2017] [Indexed: 01/15/2023]
Abstract
Human immune virus subtype C is the most widely spread HIV subtype in Sub-Sahara Africa and South Africa. A profound structural insight on finding potential lead compounds is therefore necessary for drug discovery. The focus of this study is to rationalize the nine Food and Drugs Administration (FDA) HIV antiviral drugs complexed to subtype B and C-SA PR using ONIOM approach. To achieve this, an integrated two-layered ONIOM model was used to optimize the geometrics of the FDA approved HIV-1 PR inhibitors for subtype B. In our hybrid ONIOM model, the HIV-1 PR inhibitors as well as the ASP 25/25' catalytic active residues were treated at high level quantum mechanics (QM) theory using B3LYP/6-31G(d), and the remaining HIV PR residues were considered using the AMBER force field. The experimental binding energies of the PR inhibitors were compared to the ONIOM calculated results. The theoretical binding free energies (?Gbind) for subtype B follow a similar trend to the experimental results, with one exemption. The computational model was less suitable for C-SA PR. Analysis of the results provided valuable information about the shortcomings of this approach. Future studies will focus on the improvement of the computational model by considering explicit water molecules in the active pocket. We believe that this approach has the potential to provide much improved binding energies for complex enzyme drug interactions.
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Affiliation(s)
- Z K Sanusi
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4001, South Africa
| | - T Govender
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4001, South Africa
| | - G E M Maguire
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4001, South Africa; School of Chemistry and Physics, University of KwaZulu-Natal, 4001 Durban, South Africa
| | - S B Maseko
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4001, South Africa
| | - J Lin
- School of Life Sciences, University of KwaZulu-Natal, Durban 4001, South Africa
| | - H G Kruger
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4001, South Africa.
| | - B Honarparvar
- Catalysis and Peptide Research Unit, School of Health Sciences, University of KwaZulu-Natal, Durban 4001, South Africa.
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56
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Rambharose S, Kalhapure RS, Govender T. Nanoemulgel using a bicephalous heterolipid as a novel approach to enhance transdermal permeation of tenofovir. Colloids Surf B Biointerfaces 2017; 154:221-227. [PMID: 28343120 DOI: 10.1016/j.colsurfb.2017.03.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [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: 12/22/2016] [Revised: 02/21/2017] [Accepted: 03/17/2017] [Indexed: 11/30/2022]
Abstract
Improvements in permeation enhancement strategies, such as nanoemulsions (NEs) and nanoemulgels (NEGs), have led to a renewed interest in transdermal drug delivery (TDD). This study aimed to investigate the potential of LLA1E, a novel dendritic permeation enhancer, as an oily phase in the development of a NEG for the TDD of tenofovir (TNF). TNF loaded NEs (TNEs) were prepared and analysed for mean globule diameter (MGD), polydispersity index (PDI), zeta potential (ZP) and morphology. NEGs of the TNEs (TNEGs) were prepared and evaluated for ex vivo transdermal permeation efficacy. The skin integrity before and after the experiments was assessed using histology and transepithelial electrical resistance (TEER). TNEs had a MGD of 129.06±3.35nm, a PDI of 0.192±0.038 and a ZP of 20.9±2.02mV, with an incorporation efficiency of 91.94±0.84%. There was no significant change is these properties after incorporating the TNEs into the hydrogel, as MGD, PDI and ZP of TNEGs were found to be 136.13±5.21nm, 0.182±0.020 and -20.9±2.08mV respectively. Ex vivo permeation studies showed that the TNEG significantly enhanced the TNF permeation by 39.65-fold, with a cumulative amount of 1866.54±108.62μgcm-2. Histological and TEER assessments showed no permanent effects on the skin by TNEG, indicating that this novel TNEG nanosystem has the potential to translate into clinical trials as treatment alternatives for HIV/AIDs patients.
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Affiliation(s)
- Sanjeev Rambharose
- Department of Pharmaceutical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Rahul S Kalhapure
- Department of Pharmaceutical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.
| | - Thirumala Govender
- Department of Pharmaceutical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.
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57
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Omolo CA, Kalhapure RS, Jadhav M, Rambharose S, Mocktar C, Ndesendo VM, Govender T. Pegylated oleic acid: A promising amphiphilic polymer for nano-antibiotic delivery. Eur J Pharm Biopharm 2017; 112:96-108. [DOI: 10.1016/j.ejpb.2016.11.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 11/17/2016] [Accepted: 11/18/2016] [Indexed: 12/16/2022]
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58
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Sikwal DR, Kalhapure RS, Jadhav M, Rambharose S, Mocktar C, Govender T. Non-ionic self-assembling amphiphilic polyester dendrimers as new drug delivery excipients. RSC Adv 2017. [DOI: 10.1039/c6ra28100a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Solubility enhancement of poorly soluble antibiotics via self-assembling nano systems could be a promising approach to effectively treat bacterial infections in the current scenario of evolving resistant species.
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Affiliation(s)
- Dhiraj R. Sikwal
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban
- South Africa
| | - Rahul S. Kalhapure
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban
- South Africa
| | - Mahantesh Jadhav
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban
- South Africa
| | - Sanjeev Rambharose
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban
- South Africa
| | - Chunderika Mocktar
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban
- South Africa
| | - Thirumala Govender
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban
- South Africa
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59
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Sonawane SJ, Kalhapure RS, Govender T. Hydrazone linkages in pH responsive drug delivery systems. Eur J Pharm Sci 2016; 99:45-65. [PMID: 27979586 DOI: 10.1016/j.ejps.2016.12.011] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [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: 10/21/2016] [Revised: 11/24/2016] [Accepted: 12/09/2016] [Indexed: 01/02/2023]
Abstract
Stimuli-responsive polymeric drug delivery systems using various triggers to release the drug at the sites have become a major focus area. Among various stimuli-responsive materials, pH-responsiveness has been studied extensively. The materials used for fabricating pH-responsive drug delivery systems include a specific chemical functionality in their structure that can respond to changes in the pH of the surrounding environment. Various chemical functionalities, for example, acetal, amine, ortho ester, amine and hydrazone, have been used to design materials that are capable of releasing their payload at the acidic pH conditions of the tumor or infection sites. Hydrazone linkages are significant synthons for numerous transformations and have gained importance in pharmaceutical sciences due to their various biological and clinical applications. These linkages have been employed in various drug delivery vehicles, such as linear polymers, star shaped polymers, dendrimers, micelles, liposomes and inorganic nanoparticles, for pH-responsive drug delivery. This review paper focuses on the synthesis and characterization methods of hydrazone bond containing materials and their applications in pH-responsive drug delivery systems. It provides detailed suggestions as guidelines to materials and formulation scientists for designing biocompatible pH-responsive materials with hydrazone linkages and identifying future studies.
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Affiliation(s)
- Sandeep J Sonawane
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Rahul S Kalhapure
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa..
| | - Thirumala Govender
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa..
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60
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Sikwal DR, Kalhapure RS, Govender T. An emerging class of amphiphilic dendrimers for pharmaceutical and biomedical applications: Janus amphiphilic dendrimers. Eur J Pharm Sci 2016; 97:113-134. [PMID: 27864064 DOI: 10.1016/j.ejps.2016.11.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [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: 09/23/2016] [Revised: 11/03/2016] [Accepted: 11/10/2016] [Indexed: 01/18/2023]
Abstract
In recent years, a new class of dendrimer, known as Janus dendrimers (JDs), has attracted much attention due to their different structures and properties to the conventional symmetric forms. The broken symmetry of JDs offers the opportunity to form complex self-assembled materials, and presents new sets of properties that are presently inconceivable for homogeneous or symmetrical dendrimers. Due to their unique features, JDs have a promising future in pharmaceutical and biomedical fields, as seen from the recent interest in their application in conjugating multiple drugs and targeting moieties, forming supramolecular hydrogels, enabling micellar delivery systems, and preparing nano-vesicles, known as dendrimersomes, for drug encapsulation. The present paper is the first review, with an emphasis on various emerging applications of JDs, in the drug delivery and biomedical field reported so far. In addition, the paper describes different synthetic methods for producing JDs that can guide the design of new biocompatible forms with pharmacological activities, and that have the potential to be nano drug delivery vehicles. Furthermore, future studies to optimize the applications of JDs in drug delivery sciences and biomedical field to realize their potential to treat various disease conditions are identified and highlighted. Overall, this review identifies the current status of JDs in terms of their synthesis and applications, as well as the future research for their translation into macromolecules for clinical applications to solve health problems. It highlights the future combined efforts needed to be taken by dendrimer chemists, formulation scientist and microbiologists to develop novel antibacterials and nanomedicines from JDs.
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Affiliation(s)
- Dhiraj R Sikwal
- Discipline of Pharmaceutical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Rahul S Kalhapure
- Discipline of Pharmaceutical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.
| | - Thirumala Govender
- Discipline of Pharmaceutical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.
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61
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Abstract
A lyophilized polymeric wafer matrix was developed for rapid drug delivery via the oramucosal route. Lyophilization produced a porous wafer matrix that allowed simulated saliva (SS) to be rapidly absorbed into the hydrophilic structure. This surge of SS led to rapid disintegration of the wafer matrix. Hydroxypropylcellulose (HPC) was selected as the polymeric material based on its low gelatin potential. Other excipients incorporated into the system were lactose and mannitol as diluents, and glycine was utilized as a collapse inhibitor. A face-centered central composite design was employed to establish the significant effects of the independent formulation variables on the physico-chemical and physico-mechanical properties of the wafer matrix. The formulation variables investigated were, HPC concentration, diluent type and concentration, glycine concentration and fill volume. An analysis of these variables elucidated the influential factors that may be used to form an effective wafer matrix. HPC concentration significantly affected the wafer matrix disintegration rate ( P = 0.003), influx rate of SS ( P = 0.011) and wafer matrix friability ( P = 0.023). Diluent concentration had a significant effect on the wafer matrix tolerance ( P = 0.029) and wafer matrix friability ( P = 0.032). Statistical optimization was performed using constrained and artificial neural network techniques to predict ideal wafer formulation. Karl Fischer titrations revealed the reliability of the wafer matrices when small quantities of moisture were absorbed while being stored under ambient conditions.
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Affiliation(s)
- Rupal Patel
- Department of Pharmacy and Pharmacology, University of the Witwatersrand, Medical School, Johannesburg, Gauteng, South Africa,
| | - Viness Pillay
- Department of Pharmacy and Pharmacology, University of the Witwatersrand, Medical School, Johannesburg, Gauteng, South Africa,
| | - Yahya E. Choonara
- Department of Pharmacy and Pharmacology, University of the Witwatersrand, Medical School, Johannesburg, Gauteng, South Africa
| | - Thirumala Govender
- University of KwaZulu-Natal, School of Pharmacy and Pharmacology, Durban, South Africa
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Sikwal DR, Kalhapure RS, Rambharose S, Vepuri S, Soliman M, Mocktar C, Govender T. Polyelectrolyte complex of vancomycin as a nanoantibiotic: Preparation, in vitro and in silico studies. Materials Science and Engineering: C 2016; 63:489-98. [DOI: 10.1016/j.msec.2016.03.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 02/17/2016] [Accepted: 03/06/2016] [Indexed: 11/16/2022]
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63
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Ahmed S, Vepuri SB, Kalhapure RS, Govender T. Interactions of dendrimers with biological drug targets: reality or mystery - a gap in drug delivery and development research. Biomater Sci 2016; 4:1032-50. [PMID: 27100841 DOI: 10.1039/c6bm00090h] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Dendrimers have emerged as novel and efficient materials that can be used as therapeutic agents/drugs or as drug delivery carriers to enhance therapeutic outcomes. Molecular dendrimer interactions are central to their applications and realising their potential. The molecular interactions of dendrimers with drugs or other materials in drug delivery systems or drug conjugates have been extensively reported in the literature. However, despite the growing application of dendrimers as biologically active materials, research focusing on the mechanistic analysis of dendrimer interactions with therapeutic biological targets is currently lacking in the literature. This comprehensive review on dendrimers over the last 15 years therefore attempts to identify the reasons behind the apparent lack of dendrimer-receptor research and proposes approaches to address this issue. The structure, hierarchy and applications of dendrimers are briefly highlighted, followed by a review of their various applications, specifically as biologically active materials, with a focus on their interactions at the target site. It concludes with a technical guide to assist researchers on how to employ various molecular modelling and computational approaches for research on dendrimer interactions with biological targets at a molecular level. This review highlights the impact of a mechanistic analysis of dendrimer interactions on a molecular level, serves to guide and optimise their discovery as medicinal agents, and hopes to stimulate multidisciplinary research between scientific, experimental and molecular modelling research teams.
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Affiliation(s)
- Shaimaa Ahmed
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban, 4000, South Africa.
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64
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Sonawane SJ, Kalhapure RS, Rambharose S, Mocktar C, Vepuri SB, Soliman M, Govender T. Ultra-small lipid-dendrimer hybrid nanoparticles as a promising strategy for antibiotic delivery: In vitro and in silico studies. Int J Pharm 2016; 504:1-10. [PMID: 26992817 DOI: 10.1016/j.ijpharm.2016.03.021] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [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: 02/18/2016] [Accepted: 03/13/2016] [Indexed: 11/19/2022]
Abstract
The purpose of this study was to explore the preparation of a new lipid-dendrimer hybrid nanoparticle (LDHN) system to effectively deliver vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) infections. Spherical LDHNs with particle size, polydispersity index and zeta potential of 52.21±0.22 nm, 0.105±0.01, and -14.2±1.49 mV respectively were prepared by hot stirring and ultrasonication using Compritol 888 ATO, G4 PAMAM- succinamic acid dendrimer, and Kolliphor RH-40. Vancomycin encapsulation efficiency (%) in LDHNs was almost 4.5-fold greater than in lipid-polymer hybrid nanoparticles formulated using Eudragit RS 100. Differential scanning calorimetry and Fourier transform-infrared studies confirmed the formation of LDHNs. The interactions between the drug-dendrimer complex and lipid molecules using in silico modeling revealed the molecular mechanism behind the enhanced encapsulation and stability. Vancomycin was released from LDHNs over the period of 72 h with zero order kinetics and super case II transport mechanism. The minimum inhibitory concentration (MIC) against S. aureus and MRSA were 15.62 μg/ml and 7.81 μg/ml respectively. Formulation showed sustained activity with MIC of 62.5 μg/ml against S. aureus and 500 μg/ml against MRSA at the end of 72 and 54 h period respectively. The results suggest that the LDHN system can be an effective strategy to combat resistant infections.
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Affiliation(s)
- Sandeep J Sonawane
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001 Durban, 4000, South Africa
| | - Rahul S Kalhapure
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001 Durban, 4000, South Africa.
| | - Sanjeev Rambharose
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001 Durban, 4000, South Africa
| | - Chunderika Mocktar
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001 Durban, 4000, South Africa
| | - Suresh B Vepuri
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001 Durban, 4000, South Africa
| | - Mahmoud Soliman
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001 Durban, 4000, South Africa
| | - Thirumala Govender
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001 Durban, 4000, South Africa.
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65
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Azumah R, Dutta J, Somboro A, Ramtahal M, Chonco L, Parboosing R, Bester L, Kruger H, Naicker T, Essack S, Govender T. In vitro
evaluation of metal chelators as potential metallo- β -lactamase inhibitors. J Appl Microbiol 2016; 120:860-7. [DOI: 10.1111/jam.13085] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 01/15/2016] [Accepted: 01/26/2016] [Indexed: 01/16/2023]
Affiliation(s)
- R. Azumah
- Catalysis and Peptide Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
- Antimicrobial Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
| | - J. Dutta
- Catalysis and Peptide Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
| | - A.M. Somboro
- Catalysis and Peptide Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
- Antimicrobial Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
| | - M. Ramtahal
- Catalysis and Peptide Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
- Antimicrobial Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
| | - L. Chonco
- Department of Virology; National Health Laboratory Service; University of KwaZulu-Natal; Durban South Africa
| | - R. Parboosing
- Department of Virology; National Health Laboratory Service; University of KwaZulu-Natal; Durban South Africa
| | - L.A. Bester
- Biomedical Resource Unit; University of Kwa-Zulu Natal; Durban South Africa
| | - H.G. Kruger
- Catalysis and Peptide Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
| | - T. Naicker
- Catalysis and Peptide Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
| | - S.Y. Essack
- Antimicrobial Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
| | - T. Govender
- Catalysis and Peptide Research Unit; School of Health Sciences; University of Kwa-Zulu Natal; Durban South Africa
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66
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Kalhapure RS, Sonawane SJ, Sikwal DR, Jadhav M, Rambharose S, Mocktar C, Govender T. Solid lipid nanoparticles of clotrimazole silver complex: An efficient nano antibacterial against Staphylococcus aureus and MRSA. Colloids Surf B Biointerfaces 2015; 136:651-8. [PMID: 26492156 DOI: 10.1016/j.colsurfb.2015.10.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [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: 06/17/2015] [Revised: 09/25/2015] [Accepted: 10/02/2015] [Indexed: 01/08/2023]
Abstract
New and effective strategies to transform current antimicrobials are required to address the increasing issue of microbial resistance and declining introduction of new antibiotic drugs. In this context, metal complexes of known drugs and nano delivery systems for antibiotics are proving to be promising strategies. The aim of the study was therefore to synthesize a silver complex of clotrimazole and formulate it into a nano delivery system for enhanced and sustained antibacterial activity against susceptible and resistant Staphylococcus aureus. A silver complex of clotrimazole was synthesized, characterized and further encapsulated into solid lipid nanoparticles to evaluate its antibacterial activity against S. aureus and methicillin-resistant S. aureus (MRSA). An in vitro cytotoxicity study was performed on HepG2 cell lines to assess the overall biosafety of the synthesized clotrimazole silver complex to mammalian cells, and was found to be non-toxic to mammalian cells (cell viability >80%). The minimum inhibitory concentrations (MIC) of clotrimazole and clotrimazole-silver were 31.25 and 9.76 μg/mL against S. aureus, and 31.25 and 15.62 against MRSA, respectively. Clotrimazole SLNs exhibited MIC values of 104 and 208 μg/mL against both MSSA and MRSA at the end of 18 and 36 h, respectively, but thereafter completely lost its antibacterial activity. Clotrimazole-silver SLNs had an MIC value of 52 μg/mL up to 54 h, after which the MIC value was 104 μg/mL against both strains at the end of 72 h. Thus, clotrimazole-silver SLNs was found to be an efficient nanoantibiotic.
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Affiliation(s)
- Rahul S Kalhapure
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Sandeep J Sonawane
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Dhiraj R Sikwal
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Mahantesh Jadhav
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Sanjeev Rambharose
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Chunderika Mocktar
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
| | - Thirumala Govender
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.
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Ahmed SM, Maguire GEM, Kruger HG, Govender T. The impact of active site mutations of South African HIV PR on drug resistance: Insight from molecular dynamics simulations, binding free energy and per-residue footprints. Chem Biol Drug Des 2015; 83:472-81. [PMID: 24267738 DOI: 10.1111/cbdd.12262] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [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: 09/16/2013] [Revised: 10/28/2013] [Accepted: 11/15/2013] [Indexed: 01/31/2023]
Abstract
Molecular dynamics simulations and binding free energy calculations were used to provide an understanding of the impact of active site drug-resistant mutations of the South African HIV protease subtype C (C-SA HIV PR), V82A and V82F/I84V on drug resistance. Unique per-residue interaction energy 'footprints' were developed to map the overall drug-binding profiles for the wild type and mutants. Results confirmed that these mutations altered the overall binding landscape of the amino acid residues not only in the active site region but also in the flaps as well. Four FDA-approved drugs were investigated in this study; these include ritonavir (RTV), saquinavir (SQV), indinavir (IDV), and nelfinavir (NFV). Computational results compared against experimental findings were found to be complementary. Against the V82F/I84V variant, saquinavir, indinavir, and nelfinavir lose remarkable entropic contributions relative to both wild-type and V82A C-SA HIV PRs. The per-residue energy 'footprints' and the analysis of ligand-receptor interactions for the drug complexes with the wild type and mutants have also highlighted the nature of drug interactions. The data presented in this study will prove useful in the design of more potent inhibitors effective against drug-resistant HIV strains.
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Affiliation(s)
- Shaimaa M Ahmed
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Durban, 4001, South Africa
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Rambharose S, Kalhapure RS, Akamanchi KG, Govender T. Novel dendritic derivatives of unsaturated fatty acids as promising transdermal permeation enhancers for tenofovir. J Mater Chem B 2015; 3:6662-6675. [DOI: 10.1039/c5tb00957j] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Novel dendritic ester derivatives of unsaturated fatty acids as potential transdermal permeation enhancers.
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Affiliation(s)
- Sanjeev Rambharose
- Department of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
- School of Laboratory Medicine and Medical Sciences
| | - Rahul S. Kalhapure
- Department of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | | | - Thirumala Govender
- Department of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
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69
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Suleman N, Kalhapure RS, Mocktar C, Rambharose S, Singh M, Govender T. Silver salts of carboxylic acid terminated generation 1 poly (propyl ether imine) (PETIM) dendron and dendrimers as antimicrobial agents against S. aureus and MRSA. RSC Adv 2015. [DOI: 10.1039/c5ra03179f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this study the newly synthesised PETIM silver salts displayed a low toxicity level and showed significant antimicrobial activity against both sensitive (S. aureus) and resistant (MRSA) bacterial strains.
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Affiliation(s)
- Nadia Suleman
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Rahul S. Kalhapure
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Chunderika Mocktar
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Sanjeev Rambharose
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Moganavelli Singh
- Discipline of Biochemistry
- School of Life Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Thirumala Govender
- Discipline of Pharmaceutical Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
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Sonawane SJ, Kalhapure RS, Jadhav M, Rambharose S, Mocktar C, Govender T. Transforming linoleic acid into a nanoemulsion for enhanced activity against methicillin susceptible and resistant Staphylococcus aureus. RSC Adv 2015. [DOI: 10.1039/c5ra16248c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Schematic of formation of linoleic acid nanoemulsion.
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Affiliation(s)
- Sandeep J. Sonawane
- Discipline of Pharmaceutical Sciences
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Rahul S. Kalhapure
- Discipline of Pharmaceutical Sciences
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Mahantesh Jadhav
- Discipline of Pharmaceutical Sciences
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Sanjeev Rambharose
- Discipline of Pharmaceutical Sciences
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Chunderika Mocktar
- Discipline of Pharmaceutical Sciences
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
| | - Thirumala Govender
- Discipline of Pharmaceutical Sciences
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4000
- South Africa
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Kalhapure RS, Suleman N, Mocktar C, Seedat N, Govender T. Nanoengineered drug delivery systems for enhancing antibiotic therapy. J Pharm Sci 2014; 104:872-905. [PMID: 25546108 DOI: 10.1002/jps.24298] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [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: 10/14/2014] [Revised: 11/07/2014] [Accepted: 11/07/2014] [Indexed: 12/12/2022]
Abstract
Formulation scientists are recognizing nanoengineered drug delivery systems as an effective strategy to overcome limitations associated with antibiotic drug therapy. Antibiotics encapsulated into nanodelivery systems will contribute to improved management of patients with various infectious diseases and to overcoming the serious global burden of antibiotic resistance. An extensive review of several antibiotic-loaded nanocarriers that have been formulated to target drugs to infectious sites, achieve controlled drug release profiles, and address formulation challenges, such as low-drug entrapment efficiencies, poor solubility and stability is presented in this paper. The physicochemical properties and the in vitro/in vivo performances of various antibiotic-loaded delivery systems, such as polymeric nanoparticles, micelles, dendrimers, liposomes, solid lipid nanoparticles, lipid-polymer hybrid nanoparticles, nanohybirds, nanofibers/scaffolds, nanosheets, nanoplexes, and nanotubes/horn/rods and nanoemulsions, are highlighted and evaluated. Future studies that will be essential to optimize formulation and commercialization of these antibiotic-loaded nanosystems are also identified. The review presented emphasizes the significant formulation progress achieved and potential that novel nanoengineered antibiotic drug delivery systems have for enhancing the treatment of patients with a range of infections.
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Affiliation(s)
- Rahul S Kalhapure
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Durban, 4000, South Africa
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Kalhapure RS, Govender T, Akamanchi KG. Phosphine-Free Tetradentate Salicylaldimine Ligand Complexed with Palladium: First Application in Heck Reactions. SYNTHETIC COMMUN 2014. [DOI: 10.1080/00397911.2014.941501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Kapse-Mistry S, Govender T, Srivastava R, Yergeri M. Nanodrug delivery in reversing multidrug resistance in cancer cells. Front Pharmacol 2014; 5:159. [PMID: 25071577 PMCID: PMC4090910 DOI: 10.3389/fphar.2014.00159] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [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: 10/30/2013] [Accepted: 06/19/2014] [Indexed: 12/25/2022] Open
Abstract
Different mechanisms in cancer cells become resistant to one or more chemotherapeutics is known as multidrug resistance (MDR) which hinders chemotherapy efficacy. Potential factors for MDR includes enhanced drug detoxification, decreased drug uptake, increased intracellular nucleophiles levels, enhanced repair of drug induced DNA damage, overexpression of drug transporter such as P-glycoprotein(P-gp), multidrug resistance-associated proteins (MRP1, MRP2), and breast cancer resistance protein (BCRP). Currently nanoassemblies such as polymeric/solid lipid/inorganic/metal nanoparticles, quantum dots, dendrimers, liposomes, micelles has emerged as an innovative, effective, and promising platforms for treatment of drug resistant cancer cells. Nanocarriers have potential to improve drug therapeutic index, ability for multifunctionality, divert ABC-transporter mediated drug efflux mechanism and selective targeting to tumor cells, cancer stem cells, tumor initiating cells, or cancer microenvironment. Selective nanocarrier targeting to tumor overcomes dose-limiting side effects, lack of selectivity, tissue toxicity, limited drug access to tumor tissues, high drug doses, and emergence of multiple drug resistance with conventional or combination chemotherapy. Current review highlights various nanodrug delivery systems to overcome mechanism of MDR by neutralizing, evading, or exploiting the drug efflux pumps and those independent of drug efflux pump mechanism by silencing Bcl-2 and HIF1α gene expressions by siRNA and miRNA, modulating ceramide levels and targeting NF-κB. “Theragnostics” combining a cytotoxic agent, targeting moiety, chemosensitizing agent, and diagnostic imaging aid are highlighted as effective and innovative systems for tumor localization and overcoming MDR. Physical approaches such as combination of drug with thermal/ultrasound/photodynamic therapies to overcome MDR are focused. The review focuses on newer drug delivery systems developed to overcome MDR in cancer cell.
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Affiliation(s)
- Sonali Kapse-Mistry
- Department of Pharmaceutics, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, University of Mumbai Mumbai, India
| | - Thirumala Govender
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal Durban, South Africa
| | - Rohit Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay Mumbai, India
| | - Mayur Yergeri
- Department of Pharmaceutical Chemistry, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, University of Mumbai Mumbai, India
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75
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Kalhapure RS, Akamanchi KG, Mocktar C, Govender T. Synthesis and Antibacterial Activity of Silver Nanoparticles Capped with a Carboxylic Acid-terminated Generation 1 Oleodendrimer. CHEM LETT 2014. [DOI: 10.1246/cl.140151] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Rahul S. Kalhapure
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal
| | | | - Chunderika Mocktar
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal
| | - Thirumala Govender
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal
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76
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Abstract
The aim of this study was to explore the potential of novel oleic acid (OA) derivatives as buccal permeation enhancers for the delivery of didanosine (ddI). The OA derivatives, i.e. ester derivative (OA1E), the dicarboxylic acid derivative (OA1A) and the bicephalous dianionic surfactant (OA1ANa) were synthesized and their effects were compared to the parent OA. OA, OA1E, OA1A and OA1ANa at 1% w/w all showed potential for enhancing the buccal permeability of ddI with enhancement ratio (ER) of 1.29, 1.33, 1.01 and 1.72, respectively. OA1ANa at 1% w/w demonstrated the highest flux (80.30 ± 10.37 µg cm(-2 )h), permeability coefficient (4.01 ± 0.57 × 10(-3) cm h(-1)) and ER (1.72). The highest flux for ddI (144.00 ± 53.54 µg cm(-2 )h) was reported with OA1ANa 2% w/w, which displayed an ER of 3.09 more than that with ddI alone. At equivalent concentrations, OA1ANa (ER = 3.09) had a significantly higher permeation-enhancing effect than its parent OA (ER = 1.54). Histomorphological studies confirmed that OA1ANa at all concentrations (0.5, 2.0 and 6.0% w/w) had no adverse effects on the mucosae. Morphological changes such as vacuoles formation and increased intercellular spaces were attributed to the buccal permeation-enhancing effect of OA1ANa. This study demonstrated the potential of novel OA derivatives as buccal permeation enhancers. OA1ANa at 2% w/w was also identified as the optimal novel OA derivative to widen the pool of fatty acid derivatives as chemical permeation enhancers for buccal drug delivery.
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Affiliation(s)
- Elizabeth Ojewole
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal , Durban, KwaZulu-Natal , South Africa and
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Jones E, Ojewole E, Kalhapure R, Govender T. In vitrocomparative evaluation of monolayered multipolymeric films embedded with didanosine-loaded solid lipid nanoparticles: a potential buccal drug delivery system for ARV therapy. Drug Dev Ind Pharm 2014; 40:669-79. [DOI: 10.3109/03639045.2014.892957] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Rambharose S, Ojewole E, Branham M, Kalhapure R, Govender T. High-energy ball milling of saquinavir increases permeability across the buccal mucosa. Drug Dev Ind Pharm 2014; 40:639-48. [DOI: 10.3109/03639045.2014.884120] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [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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Abstract
Dendrimers are a relatively new class of monodisperse polymers, which have tree-like spherical structures with well-defined sizes and shapes. Their unique structure has a significant impact on their physical and chemical properties. Research on dendrimers is of significant interest to scientists from all areas and their utility in various scientific fields, including pharmaceuticals, is expanding. The present review is comprehensive and covers different aspects of dendrimers viz. (1) synthesis, (2) properties and (3) pharmaceutical applications. The emphasis is on their applications as well as the current ongoing research status for drug targeting.
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Affiliation(s)
- Rahul S Kalhapure
- Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal , Durban , South Africa and
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Jones E, Ojewole E, Pillay V, Kumar P, Rambharose S, Govender T. Monolayered multipolymeric buccal films with drug and polymers of opposing solubilities for ARV therapy: Physico-mechanical evaluation and molecular mechanics modelling. Int J Pharm 2013; 455:197-212. [DOI: 10.1016/j.ijpharm.2013.07.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 07/13/2013] [Accepted: 07/15/2013] [Indexed: 10/26/2022]
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du Toit LC, Carmichael T, Govender T, Kumar P, Choonara YE, Pillay V. In Vitro, In Vivo, and In Silico Evaluation of the Bioresponsive Behavior of an Intelligent Intraocular Implant. Pharm Res 2013; 31:607-34. [DOI: 10.1007/s11095-013-1184-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 08/09/2013] [Indexed: 11/29/2022]
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82
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Du Toit LC, Govender T, Carmichael T, Kumar P, Choonara YE, Pillay V. Design of an Anti-Inflammatory Composite Nanosystem and Evaluation of Its Potential for Ocular Drug Delivery. J Pharm Sci 2013; 102:2780-805. [DOI: 10.1002/jps.23650] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 05/17/2013] [Accepted: 06/10/2013] [Indexed: 12/31/2022]
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83
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Rambharose S, Ojewole E, Mackraj I, Govender T. Comparative buccal permeability enhancement of didanosine and tenofovir by potential multifunctional polymeric excipients and their effects on porcine buccal histology. Pharm Dev Technol 2013; 19:82-90. [DOI: 10.3109/10837450.2012.752505] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [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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84
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Ahmed SM, Kruger HG, Govender T, Maguire GEM, Sayed Y, Ibrahim MAA, Naicker P, Soliman MES. Comparison of the Molecular Dynamics and Calculated Binding Free Energies for Nine FDA-Approved HIV-1 PR Drugs Against Subtype B and C-SA HIV PR. Chem Biol Drug Des 2012; 81:208-18. [DOI: 10.1111/cbdd.12063] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Branham ML, Buth SM, Govender T, Ross EA. Effect of ultrasound-facilitated fixation on oral mucosa density and morphology. Biotech Histochem 2012; 87:331-9. [DOI: 10.3109/10520295.2012.655778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Govender T, Ramanna L, Rawat I, Bux F. BODIPY staining, an alternative to the Nile Red fluorescence method for the evaluation of intracellular lipids in microalgae. Bioresour Technol 2012; 114:507-11. [PMID: 22464420 DOI: 10.1016/j.biortech.2012.03.024] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 02/15/2012] [Accepted: 03/07/2012] [Indexed: 05/03/2023]
Abstract
In order to develop feasible production processes for microalgal biodiesel, the isolation of high neutral lipid producing microalgae is crucial. Since the established Nile Red (NR) method for detection of intracellular lipids has been successful only for some microalgae, a more broadly applicable detection method would be desirable. Therefore, BODIPY 505/515, a lipophilic bright green fluorescent dye was tested for detection of intracellular lipids in Chlorella vulgaris, Dunaliella primolecta and Chaetoceros calcitrans. An optimum concentration of 0.067 μg ml(-1) was determined for lipid staining in the microalgae. Compared to NR, BODIPY 505/515 was more effective in staining microalgae and showed resistance to photobleaching, maintaining its fluorescence longer than 30 min.
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Affiliation(s)
- T Govender
- Institute for Water and Wastewater Technology, Durban University of Technology, Durban 4001, South Africa
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Yang DJ, Xiong CD, Govender T, Wang YZ. Preparation and Drug-Delivery Potential of Metronidazole-Loaded PELA Tri-block Co-polymeric Electrospun Membranes. Journal of Biomaterials Science, Polymer Edition 2012; 20:1321-34. [DOI: 10.1163/156856209x453024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- De-Juan Yang
- a Center for Degradable and Flame-Retardant Polymeric Materials (MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610064, P.R. China; Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, P.R. China
| | - Cheng-Dong Xiong
- b Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, P.R. China
| | - Thirumala Govender
- c School of Pharmacy and Pharmacology, University of KwaZulu-Natal, Durban 4000, South Africa
| | - Yu-Zhong Wang
- d Center for Degradable and Flame-Retardant Polymeric Materials (MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610064, P.R. China
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Loveland JA, Govender T, Botha J, Britz R. Paediatric liver transplantation in Johannesburg: initial 29 cases and prospects for the future. S Afr Med J 2012; 102:233-236. [PMID: 22464505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Accepted: 08/22/2011] [Indexed: 05/31/2023] Open
Abstract
BACKGROUND The Wits Donald Gordon Medical Centre paediatric liver transplant programme is the second such unit in sub-Saharan Africa. Initiated in November 2005, it forms part of the centre's solid organ transplant unit, comprising kidney, liver and simultaneous kidney-pancreas arms. Initially established in the private sector, we recently received government approval to expand our programme into the provincial sector and have performed transplants on several provincial-sector patients. Current challenges relate to the lack of appropriately trained paediatric sub-specialists, specifically critical care practitioners and hepatologists. METHODS Subsequent to institutional approval, a retrospective chart analysis of all paediatric liver transplants performed at our facility to date was conducted. RESULTS Defining children as those under 18 years of age, 29 patients have received a cadaveric liver transplant since 2005, using 16 whole livers, 10 reduced-size grafts, and 3 split segments; 13 were transplanted with biliary atresia, 3 hyperoxalurea, 3 autosomal recessive polycystic disease, 2 alpha-1 antitrypsin deficiency, and 2 idiopathic, with the remainder for a wide spectrum of other pathologies. Seven patients received combined liver-kidney transplants. There were 3 in-hospital mortalities. The remaining 26 patients are all long-term survivors. We describe 7 acute surgical morbidities in 6 patients, and 8 long-term surgical morbidities. One patient was subsequently re-transplanted in Cape Town. CONCLUSIONS Despite a shortage of organs, we have overcome a steep learning curve, with results comparable with other early series. The current threat to the continued viability of our unit is the lack of appropriately trained paediatric hepatologists and intensivists.
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Affiliation(s)
- J A Loveland
- Department of Paediatric Surgery, Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa.
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Ojewole E, Mackraj I, Akhundov K, Hamman J, Viljoen A, Olivier E, Wesley-Smith J, Govender T. Investigating the effect of Aloe vera gel on the buccal permeability of didanosine. Planta Med 2012; 78:354-361. [PMID: 22161764 DOI: 10.1055/s-0031-1280431] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The buccal mucosal route offers several advantages but the delivery of certain drugs can be limited by low membrane permeability. This study investigated the buccal permeability properties of didanosine (ddI) and assessed the potential of Aloe vera gel (AVgel) as a novel buccal permeation enhancer. Permeation studies were performed using Franz diffusion cells, and the drug was quantified by UV spectroscopy. Histomorphological evaluations were undertaken using light and transmission electron microscopy. The permeability of ddI was concentration-dependent, and it did not have any adverse effects on the buccal mucosae. A linear relationship (R² = 0.9557) between the concentrations and flux indicated passive diffusion as the mechanism of drug transport. AVgel at concentrations of 0.25 to 2 %w/v enhanced ddI permeability with enhancement ratios from 5.09 (0.25 %w/v) to 11.78 (2 %w/v) but decreased permeability at 4 and 6 %w/v. Ultrastructural analysis of the buccal mucosae treated with phosphate buffer saline pH 7.4 (PBS), ddI/PBS, and ddI/PBS/AVgel 0.5 %w/v showed cells with normal plasmalemma, well-developed cristae, and nuclei with regular nuclear envelopes. However, cells from 1, 2, and 6 %w/v AVgel-treated mucosae showed irregular nuclear outlines, increased intercellular spacing, and plasmalemma crenulations. This study demonstrates the potential of AVgel as a buccal permeation enhancer for ddI to improve anti-HIV and AIDS therapy.
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Affiliation(s)
- Elizabeth Ojewole
- School of Pharmacy and Pharmacology, University of KwaZulu-Natal, Durban, South Africa
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90
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Branham ML, Singh P, Bisetty K, Sabela M, Govender T. Preparation, spectrochemical, and computational analysis of L-carnosine (2-[(3-aminopropanoyl)amino]-3-(1H-imidazol-5-yl)propanoic acid) and its ruthenium (II) coordination complexes in aqueous solution. Molecules 2011; 16:10269-91. [PMID: 22158629 PMCID: PMC6264669 DOI: 10.3390/molecules161210269] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 11/05/2011] [Accepted: 11/10/2011] [Indexed: 11/16/2022] Open
Abstract
This study reports the synthesis and characterization of novel ruthenium (II) complexes with the polydentate dipeptide, L-carnosine (2-[(3-aminopropanoyl)amino]-3-(1H-imidazol-5-yl)propanoic acid). Mixed-ligand complexes with the general composition [ML(p)(Cl)(q)(H₂O)(r)]·xH₂O (M = Ru(II); L = L-carnosine; p = 3 - q; r = 0-1; and x = 1-3) were prepared by refluxing aqueous solutions of the ligand with equimolar amounts of ruthenium chloride (black-alpha form) at 60 °C for 36 h. Physical properties of the complexes were characterized by elemental analysis, DSC/TGA, and cyclic voltammetry. The molecular structures of the complexes were elucidated using UV-Vis, ATR-IR, and heteronuclear NMR spectroscopy, then confirmed by density function theory (DFT) calculations at the B3LYP/LANL2DZ level. Two-dimensional NMR experiments (¹H COSY, ¹³C gHMBC, and ¹⁵N gHMBC) were also conducted for the assignment of chemical shifts and calculation of relative coordination-induced shifts (RCIS) by the complex formed. According to our results, the most probable coordination geometries of ruthenium in these compounds involve nitrogen (N1) from the imidazole ring and an oxygen atom from the carboxylic acid group of the ligand as donor atoms. Additional thermogravimetric and electrochemical data suggest that while the tetrahedral-monomer or octahedral-dimer are both possible structures of the formed complexes, the metal in either structure occurs in the ²⁺ oxidation state. Resulting RCIS values indicate that the amide-carbonyl, and the amino-terminus of the dipeptide are not involved in chelation and these observations correlate well with theoretical shift predictions by DFT.
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Affiliation(s)
- Michael Lee Branham
- School of Pharmacy and Pharmacology, University of KwaZulu-Natal, Durban, 4001, South Africa; (T.G.)
| | - Parvesh Singh
- Department of Chemistry, Durban University of Technology, Durban, 4001, South Africa; (P.S.); (K.B.); (M.S.)
| | - Krishna Bisetty
- Department of Chemistry, Durban University of Technology, Durban, 4001, South Africa; (P.S.); (K.B.); (M.S.)
| | - Myalo Sabela
- Department of Chemistry, Durban University of Technology, Durban, 4001, South Africa; (P.S.); (K.B.); (M.S.)
| | - Thirumala Govender
- School of Pharmacy and Pharmacology, University of KwaZulu-Natal, Durban, 4001, South Africa; (T.G.)
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91
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Branham ML, Moyo T, Govender T. Preparation and solid-state characterization of ball milled saquinavir mesylate for solubility enhancement. Eur J Pharm Biopharm 2011; 80:194-202. [PMID: 21906676 DOI: 10.1016/j.ejpb.2011.08.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [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: 05/03/2011] [Revised: 08/11/2011] [Accepted: 08/19/2011] [Indexed: 12/22/2022]
Abstract
Saquinavir is an anti-retroviral drug with very low oral bioavailability (e.g. 0.7-4.0%) due to its affinity toward efflux transporters (P-gp) and metabolic enzymes (CYP3A4). The aim of this study was to characterize the effects of high-energy ball milling on saquinavir solid-state characteristics and aqueous solubility for the design of effective buccal drug delivery systems. The solubility of saquinavir mesylate was evaluated in simulated saliva before and after milling for 1, 3, 15, 30, 50, and 60 h. To elucidate changes in crystallinity and long-range structure in the drug, analyses of the milled powders were performed using XRD, ATR-IR, DSC/TGA, BET surface area, EDX and SEM. In addition, the effects of milling time on saquinavir solubility were statistically correlated using repeated measures ANOVA. Results of this study indicate that the milling of saquinavir mesylate produces nanoporous particles with unique surface structures, thermal properties, and increased aqueous solubility. Optimal milling time occurred at 3h and corresponded to a 9-fold solubility enhancement in simulated saliva. Thermal analysis revealed only a slight decrease in melting point (T(m)) from 242 °C to 236 °C after 60 h milling. XRD diffractograms indicate a gradual crystalline-to-amorphous transition with some residual crystallinity remaining after 60 h milling time. Unstable polymorphic structures appeared between 15 and 30 h which were converted to more stable isomorphs at 60 h. Aggregate formation also seems to occur after 15 h but no metal contamination of the drug was observed during the milling process as determined by EDX analysis. In conclusion, high-energy ball milling may be a method of choice for improving the solubility of saquinavir and facilitating novel drug formulations design.
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Affiliation(s)
- Michael Lee Branham
- School of Pharmacy and Pharmacology, University of KwaZulu-Natal, Durban, South Africa.
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92
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Murambiwa P, Masola B, Govender T, Mukaratirwa S, Musabayane C. Anti-malarial drug formulations and novel delivery systems: a review. Acta Trop 2011; 118:71-9. [PMID: 21439929 DOI: 10.1016/j.actatropica.2011.03.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/15/2011] [Accepted: 03/16/2011] [Indexed: 10/18/2022]
Abstract
Artemisinin combination therapies have decreased malaria associated morbidity and mortality in several parts of the world. On the other hand, malaria cases have increased in sub-Saharan Africa largely due to falciparum resistance to the most frequently used drugs (chloroquine and sulphadoxine/pyrimethamine (SP) combination). Therapeutic failure has also been attributed in part to adverse effects of anti-malarial drugs and patients' non-compliance due to inconvenient dosing schedules. We consider that formulation and evaluation of novel drug delivery systems is not only less expensive than developing new drugs, but may also improve delivery of anti-malarials at the desired rates. In this review we evaluate the therapeutic efficacy of existing anti-malarial drugs and assess the feasibility of developing novel formulations and delivery systems.
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93
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Abstract
IMPORTANCE OF THE FIELD A major challenge emanating in the design of topical ophthalmic preparations is their short precorneal residence time. Retention of a drug delivery system in the front of the eye is thus desirable. One solution identified to address this concern is a retentive system that can preferably be delivered in a liquid drop form and ultimately remain attached to the corneal tissue owing to incorporation of a bioadhesive component. Forward-thinking approaches are required to achieve advancements in this approach for the attainment of an effective drug concentration at the site of action. Accordingly, several investigators have identified the benefits of nanotechnology-based drug delivery systems for ophthalmic drug delivery. AREAS COVERED IN THIS REVIEW A concerted effort was made to review critically all 'nanobioadhesives', that is, nanosystems designed for ocular drug delivery with the goal of attaining prolonged ocular retention, in a systematic, chronological manner, from their reported point of inception to the present. WHAT THE READER WILL GAIN A perspective on possible future trends in this growing field of ocular drug delivery is formulated. TAKE HOME MESSAGE The importance of and need for new developments in the field of ocular nanobioadhesives is emphasized.
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Affiliation(s)
- Lisa C du Toit
- University of the Witwatersrand, Department of Pharmacy and Pharmacology, 7 York Road, Parktown, 2193, Johannesburg, South Africa
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94
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du Toit LC, Govender T, Pillay V, Choonara YE, Kodama T. Investigating the effect of polymeric approaches on circulation time and physical properties of nanobubbles. Pharm Res 2010; 28:494-504. [PMID: 21181551 DOI: 10.1007/s11095-010-0247-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 08/13/2010] [Indexed: 10/18/2022]
Abstract
PURPOSE A challenge in the field of nanobubbles, including lipobubbles and polymeric nanobubbles, is identification of formulation approaches to enhance circulation time or "bubble life" in the specific organ to allow for organ visualization. The aim of this study was to investigate the potential of two specific preparation approaches, polymeric surface modification to lipobubbles and a one-step approach for the preparation of ionotropically originated polymeric hydrogel nanobubbles for the production of biocompatible, biodegradable, and sufficiently echogenic ('flexible') bubbles, preferably within the nanometer range, that possess an enhanced in vivo lifetime compared to an unmodified lipobubble to allow visualization of the lymph node vasculature. METHODS In the first approach, formed liposomes (basic and polymerically enhanced) were sequentially layered with appropriate cationic and anionic polyelectrolytes followed by transformation into polymer-coated nanobubbles. In addition, a one-step approach was employed for the fabrication of ionotropically originated polymeric hydrogel bubbles. RESULTS Bubble lifetime was marginally enhanced by self-deposition of polyelectrolytes onto the normal lipobubble, however, not significantly (P = 0.0634). In general, formulations possessing a higher ratio of anionic:cationic coats and highly anionic overall surface charge (-20.62 mV to -17.54 mV) possessed an enhanced lifetime. The improvement in bubble lifetime was significant when a purely polymeric polyionic hydrogel bubble shell was instituted compared to a normal unmodified lipobubble (P = 0.004). There was enhanced persistence of these systems compared to lipobubbles, attributed to the highly flexible, interconnected hydrogel shell which minimized gas leakage. The prolonged contrast signal may also be attributed to a degree of polymeric deposition/endothelial attachment. CONCLUSIONS This study identified the relevance of polymeric modifications to nanobubbles for an improved circulating lifetime, which would be essential for application of these systems in passive drug or gene targeting via the enhanced permeability and retention effect.
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Affiliation(s)
- Lisa C du Toit
- Department of Pharmacy and Pharmacology, University of the Witwatersrand, 7 York Road, Parktown, 2193 Johannesburg, South Africa
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95
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Munasur AP, Pillay V, Choonara YE, Mackraj I, Govender T. Comparing the Mucoadhesivity and Drug Release Mechanisms of Various Polymer-Containing Propranolol Buccal Tablets. Drug Dev Ind Pharm 2009; 34:189-98. [DOI: 10.1080/03639040701539842] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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96
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Pillay V, Dangor CM, Govender T, Moopanar KR, Hurbans N. Drug Release Modulation from Cross-Linked Calcium Alginate Microdiscs, 1: Evaluation of the Concentration Dependency of Sodium Alginate on Drug Entrapment Capacity, Morphology, and Dissolution Rate. Drug Deliv 2009; 5:25-34. [DOI: 10.3109/10717549809052024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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97
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Pillay V, Dangor CM, Govender T, Moopanar KR, Hurbans N. Drug Release Modulation from Cross-Linked Calcium Alginate Microdiscs, 2: Swelling, Compression, and Stability of the Hydrodynamically-Sensitive Calcium Alginate Matrix and the Associated Drug Release Mechanisms. Drug Deliv 2009; 5:35-46. [DOI: 10.3109/10717549809052025] [Citation(s) in RCA: 8] [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] Open
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98
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Ramesar S, Baijnath H, Govender T, Mackraj I. Angiotensin I-converting enzyme inhibitor activity of nutritive plants in KwaZulu-Natal. J Med Food 2008; 11:331-6. [PMID: 18598177 DOI: 10.1089/jmf.2007.569] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Traditional herbal remedies still form an integral part of South African culture, hence necessitating reports on the scientific rationale for their uses. Organic and aqueous extracts from 16 nutritive plants found in KwaZulu-Natal, South Africa were screened for angiotensin I-converting enzyme (ACE) inhibitory activity using a fluorometric enzyme assay. A plant was considered to have potential antihypertensive properties if it inhibited the ACE enzyme and thus the conversion of angiotensin I to angiotensin II by greater than 50%. Eight of the 16 plants screened demonstrated ACE inhibitory activity and satisfied these criteria. These eight plants were then subjected to a gelatin salt block test for tannins to show that the ACE inhibitory activities were not due to the presence of tannins, as tannins also inhibit ACE activity. The plants that showed ACE inhibitory activity were Amaranthus dubius, Amaranthus hybridus, Asystasia gangetica, Galinsoga parviflora, Justicia flava, Oxygonum sinuatum, Physalis viscosa, and Tulbaghia violacea. T. violacea in particular shows promise with regards to ACE inhibition as in vivo administration of this extract showed only a 2.2% increase in maximum mean arterial pressure when compared to the 14.5% increase observed in the control group after co-administration with exogenous Ang I.
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Affiliation(s)
- S Ramesar
- Discipline of Physiology and Physiological Chemistry, University of KwaZulu-Natal (Westville Campus), Durban, South Africa
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99
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Perumal VA, Govender T, Lutchman D, Mackraj I. Investigating a New Approach to Film Casting for Enhanced Drug Content Uniformity in Polymeric Films. Drug Dev Ind Pharm 2008; 34:1036-47. [DOI: 10.1080/03639040801928952] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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100
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