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Thathapudi NC, Callai-Silva N, Malhotra K, Basu S, Aghajanzadeh-Kiyaseh M, Zamani-Roudbaraki M, Groleau M, Lombard-Vadnais F, Lesage S, Griffith M. Modified host defence peptide GF19 slows TNT-mediated spread of corneal herpes simplex virus serotype I infection. Sci Rep 2024; 14:4096. [PMID: 38374240 PMCID: PMC10876564 DOI: 10.1038/s41598-024-53662-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 02/03/2024] [Indexed: 02/21/2024] Open
Abstract
Corneal HSV-1 infections are a leading cause of infectious blindness globally by triggering tissue damage due to the intense inflammation. HSV-1 infections are treated mainly with antiviral drugs that clear the infections but are inefficient as prophylactics. The body produces innate cationic host defence peptides (cHDP), such as the cathelicidin LL37. Various epithelia, including the corneal epithelium, express LL37. cHDPs can cause disintegration of pathogen membranes, stimulate chemokine production, and attract immune cells. Here, we selected GF17, a peptide containing the LL37 fragment with bioactivity but with minimal cytotoxicity, and added two cell-penetrating amino acids to enhance its activity. The resulting GF19 was relatively cell-friendly, inducing only partial activation of antigen presenting immune cells in vitro. We showed that HSV-1 spreads by tunneling nanotubes in cultured human corneal epithelial cells. GF19 given before infection was able to block infection, most likely by blocking viral entry. When cells were sequentially exposed to viruses and GF19, the infection was attenuated but not arrested, supporting the contention that the GF19 mode of action was to block viral entry. Encapsulation into silica nanoparticles allowed a more sustained release of GF19, enhancing its activity. GF19 is most likely suitable as a prevention rather than a virucidal treatment.
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Affiliation(s)
- Neethi C Thathapudi
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC, H1T 2M4, Canada
- Department of Ophthalmology, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Institute of Biomedical Engineering, Université de Montréal, Montreal, QC, H3T 1J4, Canada
| | - Natalia Callai-Silva
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC, H1T 2M4, Canada
- Department of Ophthalmology, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Institute of Biomedical Engineering, Université de Montréal, Montreal, QC, H3T 1J4, Canada
| | - Kamal Malhotra
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC, H1T 2M4, Canada
- Department of Ophthalmology, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute, University of Ottawa, Ottawa, K1Y 4W7, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, K1H 8M5, Canada
| | - Sankar Basu
- Department of Microbiology, Asutosh College, (Affiliated With University of Calcutta), Kolkata, 700026, India
| | - Mozhgan Aghajanzadeh-Kiyaseh
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC, H1T 2M4, Canada
- Department of Ophthalmology, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Institute of Biomedical Engineering, Université de Montréal, Montreal, QC, H3T 1J4, Canada
| | - Mostafa Zamani-Roudbaraki
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC, H1T 2M4, Canada
- Department of Ophthalmology, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Institute of Biomedical Engineering, Université de Montréal, Montreal, QC, H3T 1J4, Canada
| | - Marc Groleau
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC, H1T 2M4, Canada
- Department of Ophthalmology, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | | | - Sylvie Lesage
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC, H1T 2M4, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - May Griffith
- Maisonneuve-Rosemont Hospital Research Centre, Montreal, QC, H1T 2M4, Canada.
- Department of Ophthalmology, Université de Montréal, Montreal, QC, H3C 3J7, Canada.
- Institute of Biomedical Engineering, Université de Montréal, Montreal, QC, H3T 1J4, Canada.
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Gote V, Ansong M, Pal D. Prodrugs and nanomicelles to overcome ocular barriers for drug penetration. Expert Opin Drug Metab Toxicol 2020; 16:885-906. [PMID: 32729364 DOI: 10.1080/17425255.2020.1803278] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Ocular barriers hinder drug delivery and reduce drug bioavailability. This article focuses on enhancing drug absorption across the corneal and conjunctival epithelium. Both, transporter targeted prodrug formulations and nanomicellar strategy is proven to enhance the drug permeation of therapeutic agents across various ocular barriers. These strategies can increase aqueous drug solubility and stability of many hydrophobic drugs for topical ophthalmic formulations. AREAS COVERED The article discusses various ocular barriers, ocular influx, and efflux transporters. It elaborates various prodrug strategies used for enhancing drug absorption. Along with this, the article also describes nanomicellar formulation, its characteristic and advantages, and applications in for anterior and posterior segment drug delivery. EXPERT OPINION Prodrugs and nanomicellar formulations provide an effective strategy for improving drug absorption and drug bioavailability across various ocular barriers. It will be exciting to see the efficacy of nanomicelles for treating back of the eye disorders after their topical application. This is considered as a holy grail of ocular drug delivery due to the dynamic and static ocular barriers, restricting posterior entry of topically applied drug formulations.
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Affiliation(s)
- Vrinda Gote
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City , Kansas City, MO, USA
| | - Michael Ansong
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City , Kansas City, MO, USA
| | - Dhananjay Pal
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City , Kansas City, MO, USA
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Begum G, Leigh T, Courtie E, Moakes R, Butt G, Ahmed Z, Rauz S, Logan A, Blanch RJ. Rapid assessment of ocular drug delivery in a novel ex vivo corneal model. Sci Rep 2020; 10:11754. [PMID: 32678110 PMCID: PMC7366725 DOI: 10.1038/s41598-020-68254-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 06/05/2020] [Indexed: 12/29/2022] Open
Abstract
Drug delivery by topical application has higher patient acceptance and lower morbidity than intraocular injection, but many ophthalmic treatments are unable to enter the eye or reach the posterior segment after topical application. The first stage towards posterior segment delivery after topical application is ocular surface penetration and existing models are in vivo or use large quantities of tissue. We therefore developed a novel ex vivo model using discs of porcine and human cornea and sclera (5 mm diameter) to assess penetration of a candidate neuroprotective siRNA. siRNA against caspase 2 or control solutions of known penetrance were applied to the corneal epithelial surface and trans-corneal penetration and corneal adsorbance measured at fixed time points. To demonstrate that leakage did not occur, we applied dextran blue, which should not penetrate the intact cornea and did not do so in our model. Fluorescein penetration (0.09%) was less than rhodamine B (6.98%) at 60 min. siCASP2 penetration was 0.01% by 60 min. When the applied siCASP2 was washed off after 2 min, (representing lacrimal drainage) 0.071% penetrated porcine cornea by 60 min and 0.0002% penetrated human cornea and 0.001% penetrated human sclera. Our ex vivo model rapidly and cost-effectively assesses transcorneal penetration of candidate topical therapies, allowing rates of trans-corneal penetration for potential therapies such as siRNA to be evaluated with small quantities of human or animal tissue.
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Affiliation(s)
- Ghazala Begum
- miRNA Diagnostics, Birmingham, UK.,Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK.,NIHR Surgical Reconstruction and Microbiology Research Centre, University of Birmingham, Birmingham, UK
| | - Thomas Leigh
- School of Chemistry, University of Birmingham, Birmingham, UK
| | - Ella Courtie
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK.,NIHR Surgical Reconstruction and Microbiology Research Centre, University of Birmingham, Birmingham, UK
| | - Richard Moakes
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
| | - Gibran Butt
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK.,Academic Unit of Ophthalmology, Birmingham and Midland Eye Centre, University of Birmingham, Birmingham, UK
| | - Zubair Ahmed
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Saaeha Rauz
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK.,Academic Unit of Ophthalmology, Birmingham and Midland Eye Centre, University of Birmingham, Birmingham, UK
| | - Ann Logan
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK.,NIHR Surgical Reconstruction and Microbiology Research Centre, University of Birmingham, Birmingham, UK
| | - Richard J Blanch
- Neuroscience and Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK. .,NIHR Surgical Reconstruction and Microbiology Research Centre, University of Birmingham, Birmingham, UK. .,Academic Department of Military Surgery and Trauma, Royal Centre for Defence Medicine, Birmingham, UK. .,Department of Ophthalmology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
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4
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Sharma HP, Halder N, Singh SB, Velpandian T. Involvement of nucleoside transporters in the transcorneal permeation of topically instilled substrates in rabbits in-vivo. Eur J Pharm Sci 2018; 114:364-371. [DOI: 10.1016/j.ejps.2017.12.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 11/09/2017] [Accepted: 12/29/2017] [Indexed: 01/02/2023]
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Vellonen KS, Hellinen L, Mannermaa E, Ruponen M, Urtti A, Kidron H. Expression, activity and pharmacokinetic impact of ocular transporters. Adv Drug Deliv Rev 2018; 126:3-22. [PMID: 29248478 DOI: 10.1016/j.addr.2017.12.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/24/2017] [Accepted: 12/13/2017] [Indexed: 12/13/2022]
Abstract
The eye is protected by several tissues that limit the permeability and entry of potentially harmful substances, but also hamper the delivery of drugs in the treatment of ocular diseases. Active transport across the ocular barriers may affect drug distribution, but the impact of drug transporters on ocular drug delivery is not well known. We have collected and critically reviewed the literature for ocular expression and activity of known drug transporters. The review concentrates on drug transporters that have been functionally characterized in ocular tissues or primary cells and on transporters for which there is available expression data at the protein level. Species differences are highlighted, since these may explain observed inconsistencies in the influence of specific transporters on drug disposition. There is variable evidence about the pharmacokinetic role of transporters in ocular tissues. The strongest evidence for the role of active transport is available for the blood-retinal barrier. We explored the role of active transport in the cornea and blood retinal barrier with pharmacokinetic simulations. The simulations show that the active transport is important only in the case of specific parameter combinations.
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Yellepeddi VK, Palakurthi S. Recent Advances in Topical Ocular Drug Delivery. J Ocul Pharmacol Ther 2016; 32:67-82. [DOI: 10.1089/jop.2015.0047] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Venkata Kashyap Yellepeddi
- College of Pharmacy, Roseman University of Health Sciences, South Jordan, Utah
- Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, University of Utah, Salt Lake City, Utah
| | - Srinath Palakurthi
- Irma Lerma Rangel College of Pharmacy, Texas A&M Health Science Center, Kingsville, Texas
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7
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Influence of drug loading and type of ointment base on the in vitro performance of acyclovir ophthalmic ointment. Int J Pharm 2015; 495:783-91. [DOI: 10.1016/j.ijpharm.2015.08.096] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/24/2015] [Accepted: 08/27/2015] [Indexed: 11/20/2022]
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8
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Vellonen KS, Malinen M, Mannermaa E, Subrizi A, Toropainen E, Lou YR, Kidron H, Yliperttula M, Urtti A. A critical assessment of in vitro tissue models for ADME and drug delivery. J Control Release 2014; 190:94-114. [DOI: 10.1016/j.jconrel.2014.06.044] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/22/2014] [Accepted: 06/23/2014] [Indexed: 12/22/2022]
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Pharmacokinetic studies and LC-MS/MS method development of ganciclovir and dipeptide monoester prodrugs in Sprague Dawley rats. Eur J Drug Metab Pharmacokinet 2014; 40:325-34. [PMID: 24943988 DOI: 10.1007/s13318-014-0200-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 04/15/2014] [Indexed: 02/07/2023]
Abstract
Ganciclovir (GCV) is utilized as an anti-herpetic agent. Reports from our laboratory have suggested that dipeptide ester prodrugs of GCV exhibit high affinity towards the oligopeptide transporter hPEPT1 and therefore seem to be promising candidates for the treatment of oral herpes virus infections. In this study, we have examined the bio-availability of a dipeptide prodrug of GCV after oral administration in jugular cannulated Sprague-Dawley rats. A new bio-analytical method was developed with Q-TRAP liquid chromatography tandem mass spectroscopy (LC-MS/MS) for simultaneous analysis of GCV, Valine-GCV (VGCV) and Tyrosine-Valine-GCV (YVGCV). Acyclovir (ACV) was used as an internal standard in the analysis. Area under plasma-concentration time curves for total concentration of GCV after oral administration of YVGCV was found to be approximately 200 % more than that of GCV following intestinal absorption. A complete conversion of the dipeptide prodrug (YVGCV) to parent compound, GCV, by hepatic first-pass metabolism was evident due to the absence of intermediate metabolite VGCV and administered prodrug YVGCV. The dipeptide prodrugs of GCV exhibit higher systemic availability of regenerated GCV upon oral administration and thus seem to be promising drug candidate in the treatment of systemic herpes infections.
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Abstract
The eye is a highly protected organ, and designing an effective therapy is often considered a challenging task. The anatomical and physiological barriers result in low ocular bioavailability of drugs. Due to these constraints, less than 5% of the administered dose is absorbed from the conventional ophthalmic dosage forms. Further, physicochemical properties such as lipophilicity, molecular weight and charge modulate the permeability of drug molecules. Vision-threatening diseases such as glaucoma, diabetic macular edema, cataract, wet and dry age-related macular degeneration, proliferative vitreoretinopathy, uveitis, and cytomegalovirus retinitis alter the pathophysiological and molecular mechanisms. Understanding these mechanisms may result in the development of novel treatment modalities. Recently, transporter/receptor targeted prodrug approach has generated significant interest in ocular drug delivery. These transporters and receptors are involved in the transport of essential nutrients, vitamins, and xenobiotics across biological membranes. Several influx transporters (peptides, amino acids, glucose, lactate and nucleosides/nucleobases) and receptors (folate and biotin) have been identified on conjunctiva, cornea, and retina. Structural and functional delineation of these transporters will enable more drugs targeting the posterior segment to be successfully delivered topically. Prodrug derivatization targeting transporters and receptors expressed on ocular tissues has been the subject of intense research. Several prodrugs have been designed to target these transporters and enhance the absorption of poorly permeating parent drug. Moreover, this approach might be used in gene delivery to modify cellular function and membrane receptors. This review provides comprehensive information on ocular drug delivery, with special emphasis on the use of transporters and receptors to improve drug bioavailability.
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11
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Barot M, Bagui M, Gokulgandhi MR, Mitra AK. Prodrug strategies in ocular drug delivery. Med Chem 2012; 8:753-68. [PMID: 22530907 DOI: 10.2174/157340612801216283] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 03/07/2012] [Accepted: 03/22/2012] [Indexed: 11/22/2022]
Abstract
Poor bioavailability of topically instilled drug is the major concern in the field of ocular drug delivery. Efflux transporters, static and dynamic ocular barriers often possess rate limiting factors for ocular drug therapy. Different formulation strategies like suspension, ointment, gels, nanoparticles, implants, dendrimers and liposomes have been employed in order to improve drug permeation and retention by evading rate limiting factors at the site of absorption. Chemical modification such as prodrug targeting various nutrient transporters (amino acids, peptide and vitamin) has evolved a great deal of interest to improve ocular drug delivery. In this review, we have discussed various prodrug strategies which have been widely applied for enhancing therapeutic efficacy of ophthalmic drugs. The purpose of this review is to provide an update on the utilization of prodrug concept in ocular drug delivery. In addition, this review will highlight ongoing academic and industrial research and development in terms of ocular prodrug design and delivery.
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Affiliation(s)
- Megha Barot
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64108, USA
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12
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Vadlapudi AD, Vadlapatla RK, Kwatra D, Earla R, Samanta SK, Pal D, Mitra AK. Targeted lipid based drug conjugates: a novel strategy for drug delivery. Int J Pharm 2012; 434:315-24. [PMID: 22692074 DOI: 10.1016/j.ijpharm.2012.05.033] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 04/30/2012] [Accepted: 05/15/2012] [Indexed: 11/26/2022]
Abstract
A majority of studies involving prodrugs are directed to overcome low bioavailability of the parent drug. The aim of this study is to increase the bioavailability of acyclovir (ACV) by designing a novel prodrug delivery system which is more lipophilic, and at the same time site specific. In this study, a lipid raft has been conjugated to the parent drug molecule to impart lipophilicity. Simultaneously a targeting moiety that can be recognized by a specific transporter/receptor in the cell membrane has also been tethered to the other terminal of lipid raft. Targeted lipid prodrugs i.e., biotin-ricinoleicacid-acyclovir (B-R-ACV) and biotin-12hydroxystearicacid-acyclovir (B-12HS-ACV) were synthesized with ricinoleicacid and 12hydroxystearicacid as the lipophilic rafts and biotin as the targeting moiety. Biotin-ACV (B-ACV), ricinoleicacid-ACV (R-ACV) and 12hydroxystearicacid-ACV (12HS-ACV) were also synthesized to delineate the individual effects of the targeting and the lipid moieties. Cellular accumulation studies were performed in confluent MDCK-MDR1 and Caco-2 cells. The targeted lipid prodrugs B-R-ACV and B-12HS-ACV exhibited much higher cellular accumulation than B-ACV, R-ACV and 12HS-ACV in both cell lines. This result indicates that both the targeting and the lipid moiety act synergistically toward cellular uptake. The biotin conjugated prodrugs caused a decrease in the uptake of [(3)H] biotin suggesting the role of sodium dependent multivitamin transporter (SMVT) in uptake. The affinity of these targeted lipid prodrugs toward SMVT was studied in MDCK-MDR1 cells. Both the targeted lipid prodrugs B-R-ACV (20.25 ± 1.74 μM) and B-12HS-ACV (23.99 ± 3.20 μM) demonstrated higher affinity towards SMVT than B-ACV (30.90 ± 4.19 μM). Further, dose dependent studies revealed a concentration dependent inhibitory effect on [(3)H] biotin uptake in the presence of biotinylated prodrugs. Transepithelial transport studies showed lowering of [(3)H] biotin permeability in the presence of biotin and biotinylated prodrugs, further indicating a carrier mediated translocation by SMVT. Overall, results from these studies clearly suggest that these biotinylated lipid prodrugs of ACV possess enhanced affinity towards SMVT. These prodrugs appear to be potential candidates for the treatment of oral and ocular herpes virus infections, because of higher expression of SMVT on intestinal and corneal epithelial cells. In conclusion we hypothesize that our novel prodrug design strategy may help in higher absorption of hydrophilic parent drug. Moreover, this novel prodrug design can result in higher cell permeability of hydrophilic therapeutics such as genes, siRNA, antisense RNA, DNA, oligonucleotides, peptides and proteins.
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Affiliation(s)
- Aswani Dutt Vadlapudi
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108-2718, USA
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Sahin A, Hamrah P. Acute Herpetic Keratitis: What is the Role for Ganciclovir Ophthalmic Gel? OPHTHALMOLOGY AND EYE DISEASES 2012; 4:23-34. [PMID: 23650455 PMCID: PMC3619435 DOI: 10.4137/oed.s7267] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Herpes simplex keratitis (HSK) is a major cause of corneal blindness in the world. Following the primary infection, the virus enters into a latent phase. Recurrent infectious or immune keratitis cause structural damage to the cornea, scarring, and may lead to blindness. Several commercially available topical and oral antiviral drugs for HSK are currently available. However, toxicity and low patient compliance hamper their use in HSK. Further, oral antiviral drugs alone are not always effective in HSK. Thus, there had been a need for safe and effective topical antiviral agents against HSK. Systemic ganciclovir has been in use for the treatment of cytomegalovirus infections. Recently, topical ganciclovir has become available for use in patients with HSK. Ganciclovir 0.15% ophthalmic gel has been shown to be both safe and effective against viruses of the herpes family. Topical ganciclovir ophthalmic gel is well tolerated and does not cause significant toxic effects on the ocular surface. Several multicenter studies have revealed the potential role of ganciclovir ophthalmic gel in the treatment and prophylaxis of epithelial HSK. In this paper, we have reviewed the pharmacology, efficacy, side effects, and the role of ganciclovir ophthalmic gel 0.15% in the treatment of acute herpetic keratitis.
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Affiliation(s)
- Afsun Sahin
- Ocular Surface Imaging Center, Cornea and Refractive Surgery Service, Massachusetts Eye and Ear Infirmary, and Department of Ophthalmology, Harvard Medical School, Boston, MA. ; Eskisehir Osmangazi University Medical School, Department of Ophthalmology, Eskisehir, Turkey
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Suresh K, Xiadong Z, Ravi TS, Mitra AK. Small Neutral Amino Acid Ester Prodrugs of Acyclovir Targeting Amino Acid Transporters on the Cornea: Possible Antiviral Agents against Ocular HSV-1 Infections. OPHTHALMOLOGY AND EYE DISEASES 2010. [DOI: 10.1177/117917211000200002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aim of this study was to characterize the affinity and permeability patterns of the amino acid ester prodrugs of acyclovir (ACV), L-alanine-ACV (AACV), L-serine-ACV (SACV), L-serine-succinate-ACV (SSACV) and L-cysteine-ACV (CACV) on rabbit primary corneal epithelial cell culture (rPCEC) and on rabbit cornea. Amino acid prodrugs of acyclovir, AACV, SACV, SSACV and CACV were synthesized in our laboratory. Chemical hydrolysis in aqueous buffer, enzymatic hydrolysis in corneal homogenates and transport across freshly excised rabbit cornea of these prodrugs were studied. SSACV inhibited the uptake of [3H] L-alanine on rPCEC and across the intact rabbit cornea. Lineweaver-Burk plot transformation revealed competitive inhibition between L-alanine and SSACV. In corneal tissue homogenate, the half lives of SSACV, SACV and CACV (t1/2) were observed to be 3.5 ± 0.4, 9.2 ± 0.6 and 1.8 ± 0.1 hr respectively, whereas AACV was readily converted to the active parent drug acyclovir exhibiting complete degradation before 5 min. Interestingly translocation of SACV across cornea was inhibited in the presence of 5 mM arginine (~51%), a specific substrate for cationic transport system and in presence of BCH (~38%), a substrate specific for large neutral amino acid transport system (LAT) or cationic and neutral amino acid transport system (B0,+). SACV exhibited higher permeability across cornea along with excellent antiviral activity against herpes simplex virus (HSV-1) and varicella-zoster virus (VZV) in comparison to ACV. Recognition by multiple transporters, stability in corneal homogenate and changes in physico-chemical properties contributed to the increased permeability of SACV across cornea.
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Affiliation(s)
- Katragadda Suresh
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Zhu Xiadong
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Talluri S. Ravi
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Ashim K. Mitra
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, USA
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Majumdar S, Hippalgaonkar K, Srirangam R. Vitreal kinetics of quinidine in rabbits in the presence of topically coadministered P-glycoprotein substrates/modulators. Drug Metab Dispos 2009; 37:1718-25. [PMID: 19406953 DOI: 10.1124/dmd.108.026450] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The purpose of this study was to investigate whether topically administered P-glycoprotein (P-gp) substrates/modulators can alter vitreal kinetics of intravitreally administered quinidine. Male New Zealand rabbits were used under anesthesia. Vitreal kinetics of intravitreally administered quinidine (0.75-microg dose) was determined alone and in the presence of verapamil (coadministered topically/intravitreally) or prednisolone hemisuccinate sodium (PHS) (coadministered topically). In the presence of topically instilled verapamil (1% w/v), elimination half-life (t(1/2)) (176 +/- 7 min), apparent elimination rate constant (lambda(z)) (0.0039 +/- 0.0001 min(-1)), and mean retention time (MRT) (143 +/- 30 min) of intravitreally administered quinidine were significantly different from those of the control (105 +/- 11 min, 0.0066 +/- 0.0007 min(-1), and 83 +/- 13 min, respectively). A 2-fold increase in the t(1/2) with a corresponding decrease in lambda(z) and a 1.5-fold increase in the MRT of quinidine were observed in the presence of topically coadministered 2% w/v PHS. Intravitreal coadministration of quinidine and verapamil resulted in a significant increase in t(1/2) (159 +/- 9 min) and a decrease in lambda(z) (0.0043 +/- 0.0002 min(-1)) of quinidine. The vitreal pharmacokinetic parameters of sodium fluorescein, alone or in the presence of topically instilled verapamil, did not show any statistically significant difference, indicating that ocular barrier integrity was not affected by topical verapamil administration. Results from this study suggest that topically applied P-gp substrates/modulators can alter vitreal pharmacokinetics of intravitreally administered P-gp substrates, possibly through the inhibition of P-gp expressed on the basolateral membrane of the retinal pigmented epithelium.
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Affiliation(s)
- Soumyajit Majumdar
- Department of Pharmaceutics, School of Pharmacy, The University of Mississippi, University, MS 38677, USA.
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Katragadda S, Gunda S, Hariharan S, Mitra AK. Ocular pharmacokinetics of acyclovir amino acid ester prodrugs in the anterior chamber: evaluation of their utility in treating ocular HSV infections. Int J Pharm 2008; 359:15-24. [PMID: 18472234 PMCID: PMC2528302 DOI: 10.1016/j.ijpharm.2008.03.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2008] [Revised: 03/14/2008] [Accepted: 03/14/2008] [Indexed: 12/21/2022]
Abstract
PURPOSE To evaluate in vivo corneal absorption of the amino acid prodrugs of acyclovir (ACV) using a topical well model and microdialysis in rabbits. METHODS Stability of L-alanine-ACV (AACV), L-serine-ACV (SACV), L-isoleucine-ACV (IACV), gamma-glutamate-ACV (EACV) and L-valine-ACV (VACV) prodrugs was evaluated in various ocular tissues. Dose-dependent toxicity of these prodrugs was also examined in rabbit primary corneal epithelial cell culture (rPCEC) using 96-well based cell proliferation assay. In vivo ocular bioavailability of these compounds was also evaluated with a combination of topical well infusion and aqueous humor microdialysis techniques. RESULTS Among the amino acid ester prodrugs, SACV was most stable in aqueous humor. Enzymatic degradation of EACV was the least compared to all other prodrugs. Cellular toxicity of all the prodrugs was significantly less compared to trifluorothymidine (TFT) at 5mM. Absorption rate constants of all the compounds were found to be lower than the elimination rate constants. All the prodrugs showed similar terminal elimination rate constants (lambda(z)). SACV and VACV exhibited approximately two-fold increase in area under the curve (AUC) relative to ACV (p<0.05). Clast (concentration at the last time point) of SACV was observed to be 8+/-2.6microM in aqueous humor which is two and three times higher than VACV and ACV, respectively. CONCLUSIONS Amino acid ester prodrugs of ACV were absorbed through the cornea at varying rates (ka) thereby leading to varying extents (AUC). The amino acid ester prodrug, SACV owing to its enhanced stability, comparable AUC and high concentration at last time point (Clast) seems to be a promising candidate for the treatment of ocular HSV infections.
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Affiliation(s)
- Suresh Katragadda
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri
| | - Sriram Gunda
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri
| | - Sudharshan Hariharan
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri
| | - Ashim K. Mitra
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri
- Corresponding Author: Ashim K. Mitra, Ph.D., School of Pharmacy, University of Missouri-Kansas City, 5005 Rockhill Road, Kansas City, Missouri 64110-2499, U.S.A., Phone: 816-235-1615, Fax: 816-235-5190,
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Wang Z, Do CW, Avila MY, Stone RA, Jacobson KA, Civan MM. Barrier qualities of the mouse eye to topically applied drugs. Exp Eye Res 2007; 85:105-12. [PMID: 17490649 PMCID: PMC2151915 DOI: 10.1016/j.exer.2007.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Revised: 03/02/2007] [Accepted: 03/09/2007] [Indexed: 11/20/2022]
Abstract
The mouse eye displays unusually rapid intraocular pressure (IOP) responses to topically applied drugs as measured by the invasive servo-null micropipette system (SNMS). To learn if the time course reflected rapid drug transfer across the thin mouse cornea and sclera, we monitored a different parameter, pupillary size, following topical application of droplets containing 40 microM (0.073 microg) carbachol. No miosis developed from this low carbachol concentration unless the cornea was impaled with an exploring micropipette as used in the SNMS. We also compared the mouse IOP response to several purinergic drugs, measured by the invasive SNMS and non-invasive pneumotonometry. Responses to the previously studied non-selective adenosine-receptor (AR) agonist adenosine, the A(3)-selective agonist Cl-IB-MECA and the A(3)-selective antagonist MRS 1191 were all enhanced to varying degrees, in time and magnitude, by corneal impalement. We conclude that the thin ocular coats of the mouse eye actually present a substantial barrier to drug penetration. Corneal impalement with even fine-tipped micropipettes can significantly enhance entry of topically-applied drugs into the mouse aqueous humor, reflecting either direct diffusion around the tip or a more complex impalement-triggered change in ocular barrier properties. Comparison of invasive and non-invasive measurement methods can document drug efficacy at intraocular target sites even if topical drug penetration is too slow to manifest convincing physiologic effects in intact eyes.
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Affiliation(s)
- Zhao Wang
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6085
| | - Chi Wai Do
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6085
- School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Marcel Y. Avila
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6085
- Department of Physiological Sciences, Facultad de Medicina, Universidad Nacional de Colombia, Bogota, Colombia
| | - Richard A. Stone
- Department of Ophthalmology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6085
| | | | - Mortimer M. Civan
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6085
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6085
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18
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Gunda S, Hariharan S, Mitra AK. Corneal absorption and anterior chamber pharmacokinetics of dipeptide monoester prodrugs of ganciclovir (GCV): in vivo comparative evaluation of these prodrugs with Val-GCV and GCV in rabbits. J Ocul Pharmacol Ther 2007; 22:465-76. [PMID: 17238815 DOI: 10.1089/jop.2006.22.465] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
AIM The overall aim of this study was to evaluate the corneal absorption of dipeptide monoester prodrugs of ganciclovir (GCV) and compare these results with L-valine-GCV and GCV. Another aim was to evaluate the pharmacokinetics of these prodrugs in aqueous humor. METHODS A well was placed on the cornea of anesthetized New Zealand albino rabbits with linear probes implanted in the aqueous humor. Two hundred microlitres (200 microL) of a 0.43% w/v (saturation concentration) solution of GCV and equimolar concentrations of its prodrugs, VGCV, glycine-valine-GCV (GVGCV), valine-valine-GCV (VVGCV), and tyrosine-valine- GCV (YVGCV), were placed in the corneal well and were allowed to diffuse for a period of 2 h. Subsequently, the drug solution was aspirated and the well removed. Samples were collected every 20 min throughout the infusion and postinfusion phases and were analyzed by high-performance liquid chromatography to determine the aqueous humor concentrations. RESULTS Area under the concentration time profile (AUC)infinity and maximum concentration (Cmax) of YVGCV were found to be higher than other prodrugs. AUC of total GCV obtained from YVGCV administration was found to be twelvefold more than AUC of GCV and 6.2-fold more than AUC obtained with total GCV from VGCV administration. VVGCV also exhibited 3.2 times higher AUC relative to VGCV. Also, AUC and Cmax of regenerated GCV from YVGCV was 8.6 and 4.9 times more than GCV, respectively. VVGCV did not produce higher concentrations of GCV. Elimination half-life of regenerated GCV from YVGCV administration was observed to be 157 min. CONCLUSIONS YVGCV and VVGCV exhibited superior corneal absorption and bioavailability, in comparison with GVGCV, VGCV, and GCV. Such facilitated absorption of prodrugs may be a result of a combination of transcellular passive diffusion and peptide transporter (PEPT1)-mediated transport across the corneal epithelium.
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Affiliation(s)
- Sriram Gunda
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO 64110-2499, USA
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19
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Mannermaa E, Vellonen KS, Urtti A. Drug transport in corneal epithelium and blood-retina barrier: emerging role of transporters in ocular pharmacokinetics. Adv Drug Deliv Rev 2006; 58:1136-63. [PMID: 17081648 DOI: 10.1016/j.addr.2006.07.024] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Accepted: 07/31/2006] [Indexed: 12/12/2022]
Abstract
Corneal epithelium and blood-retina barrier (i.e. retinal capillaries and retinal pigment epithelium (RPE)) are the key membranes that regulate the access of xenobiotics into the ocular tissues. Corneal epithelium limits drug absorption from the lacrimal fluid into the anterior chamber after eyedrop administration, whereas blood-retina barrier restricts the entry of drugs from systemic circulation to the posterior eye segment. Like in general pharmacokinetics, the role of transporters has been considered to be quite limited as compared to the passive diffusion of drugs across the membranes. As the functional role of transporters is being revealed it has become evident that the transporters are widely important in pharmacokinetics. This review updates the current knowledge about the transporters in the corneal epithelium and blood-retina barrier and demonstrates that the information is far from complete. We also show that quite many ocular drugs are known to interact with transporters, but the studies about the expression and function of those transporters in the eye are still sparse. Therefore, the transporters probably have greater role in ocular pharmacokinetics than we currently realise.
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Affiliation(s)
- Eliisa Mannermaa
- Department of Pharmaceutics, University of Kuopio, FIN-70211 Kuopio, Finland
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Hariharan S, Janoria KG, Gunda S, Zhu X, Pal D, Mitra AK. Identification and functional expression of a carrier-mediated riboflavin transport system on rabbit corneal epithelium. Curr Eye Res 2006; 31:811-24. [PMID: 17050273 DOI: 10.1080/02713680600899655] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To investigate the functional expression of a carrier-mediated transport mechanism for riboflavin (vitamin B2) across cultured rabbit primary corneal epithelial cells (rPCECs) and intact rabbit cornea. The secondary objective was to understand the physiological significance behind the presence of such a transport system for riboflavin on the apical side of the corneal epithelium. METHODS rPCECs and freshly excised rabbit corneas were selected as in vitro and ex vivo models, respectively. Transport and uptake characteristics of [3H]riboflavin were determined at various time points, concentrations, temperatures, and pH. Substrate specificity, energy, and ion dependence studies were carried out to characterize the translocation mechanism. Rabbit tear analysis was done with liquid chromatography/tandem mass spectrometry (LC-MS/MS) to understand the physiological relevance of this transporter. RESULTS The uptake process in rPCECs was found to be concentration dependent and saturable at higher concentrations. The process was also independent of pH, Na+, and Cl- but dependent on energy and temperature. Unlabeled riboflavin and its structural analogues caused significant inhibition, whereas unrelated vitamins did not interfere with the process. Transport of [3H]riboflavin across rabbit cornea was also saturable at higher concentration and energy dependent but Na+ independent. Substrate specificity studies across intact rabbit cornea produced results similar to the uptake studies in cultured rPCECs. LC-MS/MS analysis of rabbit tears showed the presence of riboflavin. CONCLUSIONS Results suggest the presence of a specialized, high-affinity transport mechanism for riboflavin that is expressed on the apical side of rabbit corneal epithelium and may in turn be responsible for influx of riboflavin from tears to cornea.
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Affiliation(s)
- Sudharshan Hariharan
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri 64112-2499, USA
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21
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Janoria KG, Hariharan S, Paturi D, Pal D, Mitra AK. Biotin uptake by rabbit corneal epithelial cells: role of sodium-dependent multivitamin transporter (SMVT). Curr Eye Res 2006; 31:797-809. [PMID: 17038304 DOI: 10.1080/02713680600900206] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE The objective of this research was to investigate the presence of sodium-dependent multivitamin transporter (SMVT) on rabbit corneal epithelial cells. METHODS Primary cultured rabbit corneal epithelial cells (rPCECs)and freshly excised rabbit corneas were used for characterization of biotin uptake and transport, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to confirm the molecular identity of SMVT. Liquid chromatography/tandem mass spectrometry (LC-MS/MS) analysis was performed to examine the presence of biotin in rabbit tears. RESULTS Uptake of biotin by rPCECs was found to be time and concentration dependent with Km of 32.52 microM and Vmax of 10.43 pmol min- 1 mg protein- 1. Biotin was significantly inhibited in the presence of pantothenic acid and lipoic acid. Biotin uptake was found to be energy and Na+ dependent but H+ and Cl- independent. The uptake was inhibited by valeric acid in a concentration-dependent manner but not much affected in the presence of biotin methyl ester and biocytin with no free carboxyl group. Modulators of both PKC- and PKA-mediated pathways had no effect on biotin uptake, but calcium-calmodulin inhibitor significantly inhibited its uptake. Sodium-dependent multivitamin transporter was identified by RT-PCR in rPCECs. Transport experiments across the rabbit corneas revealed the functional localization of SMVT on the apical side of the cornea, and thereby corroborating with in vitro results with cultured corneal cells. Finally, LC-MS/MS analysis showed the presence of biotin in rabbit tears. CONCLUSIONS Results obtained from both in vitro and exvivo studies suggest the possible role of SMVT expressed on corneal epithelial cells for the uptake of biotin, which co-transports pantothenic acid and lipoic acid. Further, the presence of biotin in tears suggests the physiological significance of this transporter in rabbit corneal epithelium.
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Affiliation(s)
- Kumar G Janoria
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri 64110-2499, USA
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Katragadda S, Talluri RS, Mitra AK. Modulation of P-glycoprotein-mediated efflux by prodrug derivatization: an approach involving peptide transporter-mediated influx across rabbit cornea. J Ocul Pharmacol Ther 2006; 22:110-20. [PMID: 16722797 DOI: 10.1089/jop.2006.22.110] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to investigate the modulation of efflux mechanisms using transporter- targeted prodrug derivatization of a model P-gp substrate, quinidine. The L-valine, L-valine-valine esters of quinidine, val-quinidine (VQ), and val-val-quinidine (VVQ) were synthesized in our laboratory, respectively. [(14)C] erythromycin was chosen to delineate the affinity of quinidine (Q) toward P-gp. [(3)H] glycylsarcosine (GS, or glysar) was chosen as a model peptide transporter (PEPT) substrate. Uptake studies were performed on rPCEC (rabbit primary corneal epithelial culture) using 12-well plates. Transport studies were conducted with isolated rabbit corneas at 34 degrees C. Efflux of [(14)C] erythromycin was significantly increased in the presence of quinidine, whereas it was unaltered in the presence of VQ and VVQ. VVQ was more stable, both in buffers and tissue homogenate. Transport of VQ and VVQ was inhibited with GS, and their permeability values were 1.5 and 3 times higher than the permeability of quinidine, respectively. Results from this study clearly indicate that prodrug derivatization of quinidine can modulate P-gp-mediated efflux. These prodrugs have a reduced or diminished affinity toward P-gp and were further recognized by the peptide transporter- mediated process. Enhanced permeabilities of the prodrugs indicate that drug derivatization can be a viable strategy for overcoming P-gp-mediated efflux.
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Affiliation(s)
- Suresh Katragadda
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, USA
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Kawazu K, Oshita A, Nakamura T, Nakashima M, Ichikawa N, Sasaki H. Transport of Acebutolol through Rabbit Corneal Epithelium. Biol Pharm Bull 2006; 29:846-9. [PMID: 16595934 DOI: 10.1248/bpb.29.846] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study is to characterize transport of acebutolol through the corneal epithelium. Cultured normal rabbit corneal epithelial cells (RCEC) were used to investigate the drug transport. Primary RCEC were seeded on a filter membrane of Transwell-COL insert coated with fibronectin and were grown in Dulbecco's modified Eagle's medium/nutrient mixture F-12 with various supplements. Measurements of acebutolol permeability through RCEC layer were carried out to assess transcellular permeability coefficient (P(transcell)) in the absence or presence of inhibitors. Paracellular permeability coefficient (P(paracell)) was calculated by permeability coefficient of hydrophilic drugs (P(cell)). The transcellular permeability of acebutolol from apical side to basal side (A-to-B) showed concentration-dependency. The acebutolol flux in the A-to-B direction was smaller than that of opposite direction. Sodium azide, verapamil, and cyclosporin A enhanced the transcellular permeability of acebutolol in the A-to-B direction. Acebutolol permeability through an excised rabbit cornea was also increased by verapamil. Thus, it was suggested that acebutolol was actively secreted via P-glycoprotein in a corneal epithelium.
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Affiliation(s)
- Kouichi Kawazu
- Nara Research and Development Center, Santen Pharmaceutical Co., Ltd, Ikoma, Japan
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Majumdar S, Nashed YE, Patel K, Jain R, Itahashi M, Neumann DM, Hill JM, Mitra AK. Dipeptide Monoester Ganciclovir Prodrugs for Treating HSV-1-Induced Corneal Epithelial and Stromal Keratitis:In VitroandIn VivoEvaluations. J Ocul Pharmacol Ther 2005; 21:463-74. [PMID: 16386088 DOI: 10.1089/jop.2005.21.463] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The aim of this study was to evaluate a series of dipeptide monoester ganciclovir (GCV) prodrugs with the goal of improving ocular bioavailability of GCV from topical ophthalmic solutions. METHODS Solubility, logP, pH-stability profile, permeability, interaction with corneal peptide transporter, and in vivo efficacy against herpes simplex virus type 1 (HSV-1) ocular disease in the rabbit model were studied. RESULTS Val-Val-GCV, Tyr-Val-GCV, and Gly-Val-GCV were more stable in aqueous solution than Val-GCV, showing no measurable degradation even after 7 d at 37 degrees C, within the pH range of 1.4-5.4. Tyr-Val-GCV and Val-Tyr-GCV were the most lipophilic among the prodrugs synthesized and were predicted to have an n-octanol/water partition coefficient 33 times greater than that of GCV. All of the prodrugs had a much higher aqueous solubility than the parent drug. Transcorneal permeability of Val-GCV and Val-Val-GCV was seven- to eightfold greater than that of GCV, in the presence of a proton gradient, and was significantly decreased in the presence of Gly-Pro. Val-Val-GCV (1% w/v) provided significantly better therapeutic activity than trifluorothymidine (1% w/v) against HSV-1 epithelial keratitis and equivalent therapeutic activity against stromal keratitis in the rabbit eye model. CONCLUSIONS Val-Val-GCV demonstrates excellent corneal permeability and chemical stability, high aqueous solubility, and substantial in vivo antiviral activity against the HSV-1.
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Affiliation(s)
- Soumyajit Majumdar
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005 Rockhill Road, 64110-2499, USA
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Majumdar S, Tirucherai GS, Pal D, Mitra AK. Functional differences in nucleoside and nucleobase transporters expressed on the rabbit corneal epithelial cell line (SIRC) and isolated rabbit cornea. AAPS PHARMSCI 2003; 5:E15. [PMID: 12866942 PMCID: PMC2751523 DOI: 10.1208/ps050215] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The purpose of this study was to investigate the expression of nucleoside/nucleobase transporters on the Statens Seruminstitut rabbit corneal (SIRC) epithelial cell line and to evaluate SIRC as an in vitro screening tool for delineating the mechanism of corneal permeation of nucleoside analogs. SIRC cells (passages 410-425) were used to study uptake of [3H]thymidine, [3H]adenine, and [3H]ganciclovir. Transport of [3H]adenine and [3H]ganciclovir was studied across isolated rabbit cornea. Uptake and transport studies were performed for 2 minutes and 120 minutes, respectively, at 34 degrees C. Thymidine uptake by SIRC displayed saturable kinetics (K(m) = 595.9 +/- 80.4 microM, and V(max) = 289.5 +/- 17.2 pmol/min/mg protein). Uptake was inhibited by both purine and pyrimidine nucleosides but not by nucleobases. [3H]thymidine uptake was sodium and energy independent but was inhibited by nitrobenzylthioinosine at nanomolar concentrations. Adenine uptake by SIRC consisted of a saturable component (K(m) = 14.4 +/- 2.3 microM, V(max) = 0.4 +/- 0.04 nmol/min/mg protein) and a nonsaturable component. Uptake of adenine was inhibited by purine nucleobases but not by the nucleosides or pyrimidine nucleobases and was independent of sodium, energy, and nitrobenzylthioinosine. [3H]ganciclovir uptake involved a carrier-mediated component and was inhibited by the purine nucleobases but not by the nucleosides or pyrimidine nucleobases. However, transport of [3H]adenine across the isolated rabbit cornea was not inhibited by unlabeled adenine. Further, corneal permeability of ganciclovir across a 100-fold concentration range remained constant, indicating that ganciclovir permeates the cornea primarily by passive diffusion. Nucleoside and nucleobase transporters on rabbit cornea and corneal epithelial cell line, SIRC, are functionally different, undermining the utility of the SIRC cell line as an in vitro screening tool for elucidating the corneal permeation mechanism of nucleoside analogs.
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Affiliation(s)
- Soumyajit Majumdar
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005 Rockhill Road, 64110 Kansas City, MO
| | - Giridhar S. Tirucherai
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005 Rockhill Road, 64110 Kansas City, MO
- Department of Clinical Pharmacology, Quintiles Inc, 10245 Hickman Mills Drive, 64137 Kansas City, MO
| | - Dhanajay Pal
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005 Rockhill Road, 64110 Kansas City, MO
| | - Ashim K. Mitra
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005 Rockhill Road, 64110 Kansas City, MO
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