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da Silva CF, Almeida T, de Melo Barbosa R, Cardoso JC, Morsink M, Souto EB, Severino P. New Trends in Drug Delivery Systems for Veterinary Applications. Pharm Nanotechnol 2021; 9:15-25. [PMID: 32533821 DOI: 10.2174/2211738508666200613214548] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 04/24/2020] [Accepted: 05/04/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND The veterinary pharmaceutical industry has shown significant growth in recent decades. Several factors contribute to this increase as the demand for the improvement of the quality of life of both domestic and wild animals, together with the need to improve the quality, productivity, and safety of foodstuffs of animal origin. METHODS The goal of this work was to identify the most suitable medicines for animals that focus on drug delivery routes as those for humans, although they may have different devices, such as collars and ear tags. RESULTS Recent advances in drug delivery systems for veterinary use are discussed, both from academic research and the global market. The administration routes commonly used for veterinary medicines are also explored, while special attention is given to the latest technological trends to improve the drug performance, reducing the number of doses, animal stress, and side effects. CONCLUSION Drug delivery system in veterinary decreased the number of doses, side effects, and animal stress that are a small fraction of the benefits of veterinary drug delivery systems and represent a significant increase in profit for the industry; also, it demands investments in research regarding the quality, safety, and efficacy of the drug and the drug delivery systems.
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Affiliation(s)
- Classius Ferreira da Silva
- Instituto de Ciencias Ambientais, Quimicas e Farmaceuticas, Universidade Federal de Sao Paulo, Sao Paulo, Rua Sao Nicolau, 210, Diadema - SP, CEP 09913-030, Brazil
| | - Taline Almeida
- University of Tiradentes (Unit), Av. Murilo Dantas, 300, 49010- 390, Aracaju, Brazil
| | | | | | - Margaretha Morsink
- Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 65 Landsdowne Street, Cambridge, Massachusetts, 02139, United States
| | - Eliana Barbosa Souto
- Faculty of Pharmacy, University of Coimbra (FFUC), Polo das Ciências da Saude, Azinhaga de Santa Comba, 3000- 548, Coimbra, Portugal
| | - Patrícia Severino
- University of Tiradentes (Unit), Av. Murilo Dantas, 300, 49010- 390, Aracaju, Brazil
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Basu A, Domb AJ. Ion Exchange Nanoparticles for Ophthalmic Drug Delivery. Bioconjug Chem 2020; 31:2726-2736. [PMID: 33137253 DOI: 10.1021/acs.bioconjchem.0c00521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report here on ion-exchange polymeric nanoparticles from a linear copolymer of maleic anhydride methyl vinyl ether esterified with 30% octadecanol. The side chains for the polymer structure were optimized through metadynamics simulations, which revealed the use of octadecanol esters generates ideal free energy surfaces for drug encapsulation and release. Nanoparticles were synthesized using a solvent evaporation-precipitation method by mixing the polymer solution in acetone into water; upon acetone evaporation, a nanodispersion with an average particle size of ∼150 nm was obtained. Gentamicin sulfate, possessing five amino groups, was spontaneously entrapped in the nanocarrier by ionic interactions. Encapsulation efficiency increases significantly with the increase in pH and ionic strength. In vivo results demonstrate high gentamicin (GM) content in the enteric chamber (AUC 8207 ± 1334 (μg min)/mL) compared to 3% GM solution (AUC 2024 ± 438 (μg min)/mL). The formulation was also able to significantly extend the release of gentamicin when applied to rabbit cornea. These anionic nanoparticles can be used for extended-release of other cationic drugs.
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Affiliation(s)
- Arijit Basu
- School of Pharmacy, Institute of Drug Research-Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Abraham J Domb
- School of Pharmacy, Institute of Drug Research-Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
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Shamma R, Basha M, Awad G. Biodegradable multifunctional platform for potential treatment of vaginal candidiasis: In-vitro preparation, in-vivo assessment of antifungal efficacy in rats. J Drug Deliv Sci Technol 2020. [DOI: 10.1016/j.jddst.2020.101561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Metal-organic frameworks, NH 2-MIL-88(Fe), as carriers for ophthalmic delivery of brimonidine. Acta Biomater 2018; 79:344-353. [PMID: 30134206 DOI: 10.1016/j.actbio.2018.08.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/25/2018] [Accepted: 08/17/2018] [Indexed: 12/19/2022]
Abstract
We have proposed a metal-organic framework (MOF), NH2-MIL-88(Fe), as a novel carrier for topical drug delivery to the eye. The NH2-MIL-88(Fe) particles were prepared via a solvothermal synthesis method and their structure was confirmed by powder X-ray diffraction, Fourier transform infrared analysis, thermogravimetric analysis, electron microscopy, and N2 adsorption-desorption measurements. When brimonidine, an anti-glaucoma medicine, was encapsulated into NH2-MIL(Fe)-88 (i.e., NH2-MIL-88(Fe)/Br), the drug was loaded at 121.3 µg/mg and released in a sustained manner for up to 12 h. The NH2-MIL-88(Fe)/Br exhibited mucoadhesive properties and remained on rabbit eyes for a period of up to 4 h. Consequently, a high concentration of brimonidine was found in tears for a prolonged period after the administration of NH2-MIL-88(Fe)/Br, which resulted in a greater than two-fold increase in drug bioavailability and activity period compared with those of Alphagan P, which are brimonidine eye drops already approved for clinical use. Hence, NH2-MIL-88(Fe) is suggested to be a promising carrier for topical delivery to the eye that provides enhanced bioavailability of ocular drugs. STATEMENT OF SIGNIFICANCE We suggest NH2-MIL(Fe)-88, a type of metal-organic frameworks (MOFs), as delivery carriers of an ophthalmic drug, brimonidine. The NH2-MIL(Fe)-88 particles possess a mucoadhesive property, hence prolonged retention in the preocular space when topically administered to the eye. The particles can also encapsulate the drug in their micro-pores, through which the drug can be released in a sustained manner. Therefore, when tested to rabbit eyes in vivo, the drug-loaded NH2-MIL(Fe)-88 particles were shown to enhance the ocular drug bioavailability, as compared with Alphagan P, the marketed eye drops of brimonidine.
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Cho IS, Park CG, Huh BK, Cho MO, Khatun Z, Li Z, Kang SW, Choy YB, Huh KM. Thermosensitive hexanoyl glycol chitosan-based ocular delivery system for glaucoma therapy. Acta Biomater 2016; 39:124-132. [PMID: 27163401 DOI: 10.1016/j.actbio.2016.05.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 04/28/2016] [Accepted: 05/04/2016] [Indexed: 01/02/2023]
Abstract
UNLABELLED Conventional eye drops quickly move away from the surface of the eye; as a result, ocular bioavailability is very limited. To overcome this issue, we developed a thermosensitive hexanoyl glycol chitosan (HGC) as a carrier for topical drug delivery to the eye. Here, we modulated the degree of N-hexanoylation to control the thermogelling behavior and prepared a new ocular formulation of HGC for glaucoma therapy. The viscosity of the aqueous formulation sharply and significantly increases at body temperature. The results from cytotoxicity evaluation showed that HGC is non-toxic at up to 1.25wt.%. In vivo experiments demonstrated that HGC is maintained on the preocular surface for a comparatively longer period of time due to its enhanced viscosity at body temperature. As a result, when brimonidine was loaded, the formulation exhibited attractive bioavailability properties as well as more prolonged period of lowered intra-ocular pressure (14h) compared with Alphagan P, the marketed medication for brimonidine treatment. STATEMENT OF SIGNIFICANCE In this manuscript, hexanoyl glycol chitosan (HGC) was synthesized by the N-hexanoylation of glycol chitosan. We have observed that an aqueous solution of HGC exhibited a dramatic increase in viscosity as the temperature increased. The HGC-based formulation showed prolonged retention on the preocular surface and enhanced drug availability and efficacy.
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Yeluri T, Bhosale RS, Ghule NV, Raynor AM, Bhosale SV, Bhosale SV. Neomycin and gentamicin detection via molecular recognition with cyclam-decorated gold nanoparticles. Supramol Chem 2015. [DOI: 10.1080/10610278.2015.1071819] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Tanuja Yeluri
- Polymers and Functional Materials Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana 500 007, India
| | - Rajesh S. Bhosale
- Polymers and Functional Materials Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana 500 007, India
| | - Namdev V. Ghule
- Polymers and Functional Materials Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana 500 007, India
| | - Aaron M. Raynor
- School of Applied Sciences, RMIT University, GPO Box 2476, Melbourne, VIC 3001, Australia
| | - Sidhanath V. Bhosale
- Polymers and Functional Materials Division, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana 500 007, India
| | - Sheshanath V. Bhosale
- School of Applied Sciences, RMIT University, GPO Box 2476, Melbourne, VIC 3001, Australia
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Bell K, Pfeiffer N, Grus F. Pharmakokinetik am vorderen Augenabschnitt. Ophthalmologe 2014; 111:107-12. [DOI: 10.1007/s00347-013-2931-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Bozdag S, Weyenberg W, Adriaens E, Dhondt MMM, Vergote V, Vervaet C, De Prijck K, Nelis HJ, De Spiegeleer B, Ludwig A, Remon JP. In vitro evaluation of gentamicin- and vancomycin-containing minitablets as a replacement for fortified eye drops. Drug Dev Ind Pharm 2011; 36:1259-70. [PMID: 20545514 DOI: 10.3109/03639041003718030] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Ocular bioadhesive minitablets containing gentamicin and vancomycin were developed using different powder mixtures of pregelatinized starch and Carbopol (physical or cospray-dried mixtures). METHODS Drug content, antimicrobial activity, and radical formation of the powders used for tablet preparation were evaluated immediately and 30 days after gamma sterilization. Tablet properties and in vitro drug release from the sterilized minitablets were determined. Storage stability of vancomycin and gentamicin in sterilized bioadhesive mixtures was examined by LC-UV/MS and a microbiological assay, respectively. A bioadhesive powder mixture containing only vancomycin was irradiated by X electron-magnetic radiation to evaluate vancomycin stability following sterilization through irradiation. RESULTS The antimicrobial activity of gentamicin against Staphylococcus epidermidis was not altered in comparison to nonsterilized formulations. Only after an overkill dose of 50 kGy, the concentration of vancomycin decreases to an extent that was pharmaceutically significant. No significant difference in radiation stability between drug substance and product (i.e., powder mixture) was observed. A shift in stability profile was not observed at 6 weeks after irradiation. All other degradation products were present only in small quantities not exceeding 1.0%. The in vitro drug release from the minitablets prepared with physical powder mixtures of pregelatinized starch and Carbopol® 974P NF (96 : 4) was faster compared to the cospray-dried mixtures of starch with Carbopol® 974P NF (ratio: 95:5 and 85:15). The electron paramagnetic resonance signals of the radicals formed during sterilization were still visible after storage for 30 days. The slug mucosal irritation test indicated mild irritation properties of the bioadhesive powder mixtures although no tissue damage was observed.
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Affiliation(s)
- S Bozdag
- Laboratory of Pharmaceutical Technology and Biopharmacy, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
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Refai H, Tag R. Development and characterization of sponge-like acyclovir ocular minitablets. Drug Deliv 2010; 18:38-45. [DOI: 10.3109/10717544.2010.509364] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Velpandian T. Intraocular penetration of antimicrobial agents in ophthalmic infections and drug delivery strategies. Expert Opin Drug Deliv 2009; 6:255-70. [PMID: 19327043 DOI: 10.1517/17425240902798119] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Gasthuys F, Pockelé K, Vervaet C, Weyenberg W, De Prijck K, Pille F, Vlaminck L, Nelis H, Remon JP. Evaluation of the in vivo behaviour of gentamicin sulphate ocular mini-tablets in ponies. J Vet Pharmacol Ther 2007; 30:470-6. [PMID: 17803741 DOI: 10.1111/j.1365-2885.2007.00890.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The in vivo behaviour of 5% gentamicin sulphate ocular mini-tablets (2-mm diameter, 6.525 mg weight) was compared with gentamicin eye drops in six ponies. Two mini-tablets were inserted on the bulbar conjunctiva of the right eye while a similar dose of gentamicin was administered via eye drops in the left eye. Irritation induced by the mini-tablets and the eye drops was evaluated using a visual analogue scale (0-10). Tears were sampled with ophthalmologic absorption triangles for 1 min for the determination of the concentration of gentamicin sulphate using a microbiological plate diffusion method. Irritation induced by the tablets was minor and clinically acceptable (overall median score of 1.7 +/- 1.4). Eye drops induced a sharp increase in gentamicin sulphate concentration (364.4 microg/mL after 5 min) followed by a fast decline (10.8 microg/mL after 60 min). The increase in concentration induced by the ocular mini-tablets was less pronounced (up to 56.2 microg/mL after 30 min) and followed by a gradual decrease; the concentration remained above 15 microg/mL for 8 h. Ocular 5% gentamicin sulphate mini-tablets are clinically well-tolerated in ponies, assuring a constant concentration in the tears for at least 8 h.
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Affiliation(s)
- F Gasthuys
- Department of Surgery and Anaesthesiology of Domestic animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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Gubernator J, Drulis-Kawa Z, Kozubek A. A simply and sensitive fluorometric method for determination of gentamicin in liposomal suspensions. Int J Pharm 2006; 327:104-9. [PMID: 16935441 DOI: 10.1016/j.ijpharm.2006.07.039] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Revised: 07/19/2006] [Accepted: 07/20/2006] [Indexed: 11/29/2022]
Abstract
A new method for measuring gentamicin in liposomes fluorometrically is described. The assay is based on the reaction between the amino groups in the gentamicin molecule and o-phthaldialdehyde (OPA), under basic pH conditions; the product's fluorescence can be read directly on a simple fluorimeter. The effects of several factors (time of reaction, volume of the OPA reagent, and product stability) were investigated. The standard curve was linear in the concentration range of 0.5-4.0microg, showing an excellent determination coefficient of r(2)=0.99. Additionally, the influence of different liposomal lipids on gentamicin determination was tested. Liposomal lipids containing no free amino groups (PC, Chol, DOTAP) have no influence on the reaction when present in the reaction mixture. In contrast, amino groups containing lipid (SA) showed intense method interference. Therefore, a method of lipid extraction was adapted to remove undesired lipids. The described method was successfully utilised during 2 years of liposomal gentamicin experiments.
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Affiliation(s)
- Jerzy Gubernator
- Institute of Biochemistry and Molecular Biology, University of Wroclaw, Przybyszewskiego 63/77, 51-148 Wroclaw, Poland
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Weyenberg W, Bozdag S, Foreman P, Remon JP, Ludwig A. Characterization and in vivo evaluation of ocular minitablets prepared with different bioadhesive Carbopol–starch components. Eur J Pharm Biopharm 2006; 62:202-9. [PMID: 16209917 DOI: 10.1016/j.ejpb.2005.08.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 08/10/2005] [Accepted: 08/10/2005] [Indexed: 10/25/2022]
Abstract
The purpose of this study was to evaluate different bioadhesive ocular formulations based on drum dried waxy maize starch (DDWM), Amioca starch and Carbopol 974P. The concentrations of Carbopol 974P in the mixtures varied between 5 and 25% (w/w). The rheological properties of the non-sterilized and gamma-irradiated physical blends of Carbopol 974P with either DDWM or Amioca were compared to those of the corresponding co-spray dried Amioca starch/Carbopol powders. Higher viscosity or consistency values were measured for sterilized co-spray dried powder mixtures containing an amount of Carbopol 974P equal or above 15% (w/w) compared to the physical blends. Sustained release minitablets (2 mm, 6 mg), consisting of sodium fluorescein as model drug and the bioadhesive powders, were manufactured at a compression force of 1.25 kN. Afterwards, the tablets were sterilized with gamma-irradiation. The amount of Carbopol in the co-spray dried powder mixtures on the one hand and gamma-irradiation on the other hand had no significant influence on the crushing strength and friability of the minitablets evaluated. However, these two factors affected the in vitro release properties of the minitablets. The slowest release was obtained with tablets containing 25% Carbopol 974P, which unfortunately possess mucosal irritating properties. By using co-spray dried Amioca with 15% (w/w) Carbopol 974P, a slower release can be achieved compared to the physical mixtures of DDWM or Amioca starch with Carbopol 974P. Moreover, this ocular formulation is very promising and is preferred, as it did not cause any mucosal irritation and released the model drug for at least 12 h, after application in the fornix.
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Affiliation(s)
- W Weyenberg
- Laboratory of Pharmaceutical Technology and Biopharmacy, University of Antwerp, Antwerp, Belgium
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Weyenberg W, Vermeire A, D'Haese E, Vanhaelewyn G, Kestelyn P, Callens F, Nelis HJ, Remon JP, Ludwig A. Effect of different sterilisation methods on the properties of bioadhesive powders and ocular minitablets, and clinical evaluation. Eur J Pharm Sci 2005; 23:77-87. [PMID: 15324925 DOI: 10.1016/j.ejps.2004.05.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Revised: 05/11/2004] [Accepted: 05/25/2004] [Indexed: 10/26/2022]
Abstract
The purpose of this study was to evaluate the influence of gamma-irradiation and dry heat sterilisation on the properties of a bioadhesive powder mixture containing ciprofloxacin and its corresponding ocular minitablets. The molecular weight characteristics of drum dried waxy maize starch (DDWM), employed as major component of the bioadhesive formulation, the decay kinetics of radicals, the rheological properties of the bioadhesive polymers and the microbial activity of ciprofloxacin were studied. The influence of the different sterilisation methods on the characteristics of the ocular minitablets was investigated by measuring the crushing strength, the friability, and the in vitro release of ciprofloxacin from the minitablets. Finally, the clinical value of the selected sterilised minitablets was evaluated in seven healthy volunteers. Both sterilisation methods similarly affected the properties of the bioadhesive formulation by inducing stable radicals and decreasing the molecular weight of DDWM, although no changes in the microbiological activity of ciprofloxacin were measured. An obvious influence of both sterilisation methods was observed in the in vitro release study. The crushing strength and friability of the minitablets were not significantly influenced by gamma-irradiation. Based on these data, gamma-irradiation was more adequate as sterilisation method for the bioadhesive ocular minitablets than dry heat sterilisation, because it affected the least the physical properties of the minitablets. Therefore, the gamma-sterilised minitablets were selected for an in vivo evaluation in seven volunteers. The concentration of ciprofloxacin in the tear film remained above its MIC value for the most common ocular pathogens for at least 8 h. Consequently, the gamma-irradiated minitablets containing ciprofloxacin can be considered as a promising formulation to treat bacterial keratitis and conjunctivitis.
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Affiliation(s)
- W Weyenberg
- Laboratory of Pharmaceutical Technology and Biopharmacy, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium
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Levet L, Touzeau O, Scheer S, Borderie V, Laroche L. Étude de la dilatation pupillaire par l’insert ophtalmique Mydriasert®. J Fr Ophtalmol 2004; 27:1099-108. [PMID: 15687919 DOI: 10.1016/s0181-5512(04)96278-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE To evaluate the tolerance and efficiency of the Mydriasert(R) ophthalmic insert on pupil dilation. METHOD Two pharmaceutical forms of a combination of tropicamide and phenylephrine (HCl) were compared on both eyes of 80 patients. For each patient, one Mydriasert insert (Ioltech) was placed in the lower conjunctival sac of the eye. Dilation of the control eye was obtained using 0.5% tropicamide eye drops and 10% phenylephrine eye drops (Novartis Ophthalmics), which were instilled with three frequency regimens (5, 10 or 15 min). The pupil diameter was regularly measured until the maximal mydriasis had occurred. RESULTS Both subjective and objective tolerance of the insert was excellent. The size of the maximal mydriasis obtained when using the insert was significantly greater than that obtained when using the eye drops, regardless of the frequency of the instillation (p < 0.04). The difference in maximal pupil diameter ranged from +0.16 mm to +0.38 mm. Mydriasis kinetics was slower with the insert. The time necessary to obtain a maximal mydriasis was 47.3 min when the insert was used, whereas it was in the range of 31.4 to 38.5 minutes with the eye drops (p < 0.001). As far as pupil diameter is concerned, the superiority of the insert compared to the eye drops became observable only about 45 min after the insert had been placed in the eye. The relative efficacy of the insert compared to the eye drops did not correlate with patient features (p > or = 0.06). CONCLUSION Despite the small quantity of drug delivered by the insert, Mydriasert allows a much greater mydriasis compared to that usually obtained when the eye drops were used. However, a longer time lapse is necessary for this to occur.
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Affiliation(s)
- L Levet
- Service d'ophtalmologie, Hôpital des XV-XX, France
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Dumortier G, Chaumeil JC. Lachrymal Determinations: Methods and Updates on Biopharmaceutical and Clinical Applications. Ophthalmic Res 2004; 36:183-94. [PMID: 15292656 DOI: 10.1159/000078776] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Accepted: 02/25/2004] [Indexed: 11/19/2022]
Abstract
This article displays different procedures used to collect lachrymal fluid and describes some of its applications. Sampling tears represents the main difficulty to produce precise and reproducible results. The direct sampling procedure consists in collecting tears with capillary tubes and has the drawback of demanding previous stimulation that induces major dilution. The indirect method does not require preliminary stimulation but has been held responsible for altering epithelium and promoting leakage from plasma. Schirmer strips and sponges are classically required. Applications are numerous in biopharmaceutical and clinical fields. The determination of endogenous components has great potentiality as a diagnostic tool, but the use of tear as a substitute of plasma does not present clinical relevance. Levels of drugs like immunosuppressive or antibiotic agents are determined in tears to verify that pharmacological concentrations are reached and frequency of administration is deduced from kinetic fitting.
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Affiliation(s)
- G Dumortier
- Laboratoire de Galénique, UPRES EA 2498, Faculté des Sciences Pharmaceutiques et Biologiques (Paris 5), Paris, France.
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Weyenberg W, Vermeire A, Remon JP, Ludwig A. Characterization and in vivo evaluation of ocular bioadhesive minitablets compressed at different forces. J Control Release 2003; 89:329-40. [PMID: 12711455 DOI: 10.1016/s0168-3659(03)00130-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The influence of the compression force on the physical properties, the in vitro release and the in vivo behavior of ocular minitablets is evaluated in the present study. The bioerodible minitablets (Ø 2 mm, 6 mg) were produced at different compression forces. The crushing strength, friability, water uptake, hydration and swelling of the minitablets both in vitro as well as in vivo after application in the cul-de-sac were evaluated. The friability remained below 1% only for the minitablets made at 0.500 and 0.750 kN. The crushing strength measured was 3.53+/-0.98, 12.34+/-1.69 and 18.64+/-2.37 N for minitablets made at 0.250, 0.500 and 0.750 kN, respectively. The full hydration time equalled 20 and 30 min for minitablets compressed at 0.250 kN and 0.500-0.750 kN, respectively. Increasing the compression force resulted in a decreased swelling capacity. The in vivo release was evaluated in healthy volunteers using a non-invasive method to measure the apparent sodium fluorescein concentration in the tearfilm-cornea compartment as a function of time. The longest residence time of the fluorescent tracer at the administration site was obtained by the minitablets compressed at 0.750 kN. The in vitro release was evaluated with three different dissolution methods: the reciprocating cylinder method, vials in an oscillatory shaking bath and a static method with vials. The best correlation with the in vivo behavior of the matrix minitablets was obtained with the shaking bath method.
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Affiliation(s)
- W Weyenberg
- Laboratory of Pharmaceutical Technology and Biopharmacy, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium
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Frutos P, Diez-Peña E, Frutos G, Barrales-Rienda JM. Release of gentamicin sulphate from a modified commercial bone cement. Effect of (2-hydroxyethyl methacrylate) comonomer and poly(N-vinyl-2-pyrrolidone) additive on release mechanism and kinetics. Biomaterials 2002; 23:3787-97. [PMID: 12164182 DOI: 10.1016/s0142-9612(02)00028-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The influence of the (2-hydroxyethyl methacrylate) (HEMA) monomer addition as a comonomer to the cement liquid component and of a polymer, poly(N-vinyl-2-pyrrolidone) (PVP) to the solid component of a standard CMW-1 bone cement on gentamicin sulphate (GS) on its drug release properties have been studied. The addition of HEMA modifies the habit of the delivery curves. The incorporation of PVP into the cement matrix, apparently, did not very much modify the shape of the HEMA modified cement release curves, but led to a remarkable increase of the maximum amount of GS released. This effect was proportional to the PVP concentration incorporated. From the matrix composition and SEM data, a model based on the morphology of the matrix has been proposed. The cumulative amount of GS released by each slab Mt is most adequately fitted and represented by the equation Mt = c + at 1/2 + b[1 - exp(-nt)], which corroborates that the release occurs according to the model proposed. by means of three discrete mechanisms, namely: (i) a short-term initial elution due to the imperfections in the poly(methyl methacrylate) covering of the most external GS beads, burst effect by the buffer solution; (ii) followed by a fracture by stress cracking in an active media of the coated GS beads located on the external surface of the matrix where water molecules enter to dissolve GS molecules releasing them into the buffer solution by a diffusion-controlled process; and (iii) a third process in which the buffer solution penetrates into the internal voids and cracks creating a series of channels in a labyrinthic structure, which may facilitate the access of water molecules to the plastic-coated GS beads within the bulk matrix. This third process is enhanced by the incorporation of PVP beads as dissolved molecules within the matrix. This water-soluble additive is leachable, generating a highly porous structure in the cement. This HEMA and PVP modified cement may be used as a drug delivery system to modulate the GS release rate.
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Affiliation(s)
- P Frutos
- Departamento de Química-Física de Polímeros, Instituto de Ciencia y Tecnología de Polímeros, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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Kaur IP, Smitha R. Penetration enhancers and ocular bioadhesives: two new avenues for ophthalmic drug delivery. Drug Dev Ind Pharm 2002; 28:353-69. [PMID: 12056529 DOI: 10.1081/ddc-120002997] [Citation(s) in RCA: 199] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This review is focused on the two avenues of development that promise a major impact on future ocular drug therapeutics: bioadhesives, including hydrogels and other agents like carbopols, polyacrylic acids, chitosan, etc., and penetration enhancers, including different surfactants, calcium chelators, etc. The capacity of some polymers to adhere to the mucin coat covering the conjunctiva and the corneal surface of the eye forms the basis for ocular mucoadhesion. These systems markedly prolong the residence time of a drug in the conjunctival sac, since clearence is now controlled by the much slower rate of mucus turnover rather than the tear turnover rate. But improving the corneal drug retention alone is inadequate in bringing about a significant improvement of drug bioavailability. Another approach consists of transiently increasing the pentration characteristics of the cornea with appropriate substances, known as penetration enhancers or absorption promoters. The main aim of this article is to give an insight into the potential application of mucoadhesives and corneal penetration enhancers for the conception of innovative opthalmic delivery appraoches, to decrease the systemic side effects, and create a more focused effect, which may be achieved with lower doses of the drug. Ophthalmic formulations based on these mucoadhesives and penetration enhancers are simple to manufacture and exhibit an excellent tolerance when administered into the cornea. The use of the former considerably prolongs the corneal contact time and the use of the latter increases the rate and amount of drug transport. The various corneal epithelial barriers along with the major routes of transport of drugs are discussed. The article includes a list of the various substances in use or under investigation for the aforementioned properties, along with their mechanisms of action. A fair appraisal of the subject with regard to these two therapeutic approaches and any expected ill effects has been made.
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Affiliation(s)
- Indu Pal Kaur
- University Institute of Pharmaceutical Sciences, Punjab University, Chandigarh, India
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Abstract
Bioadhesion (and mucoadhesion) is the process whereby synthetic and natural macromolecules adhere to mucosal surfaces in the body. If these materials are then incorporated into pharmaceutical formulations, drug absorption by mucosal cells may be enhanced or the drug released at the site for an extended period of time. For synthetic polymers, such as the chitosans, carbopols and carbomers, the mechanism of bio/mucoadhesion is the result of a number of different physicochemical interactions. Biological bio/mucoadhesives, such as plant lectins, show specific interactions with cell surfaces and mucin and are seen as the 'second generation' bioadhesives. Bioadhesive systems for drug administration via the buccal and nasal cavities are nearing the market; in the case of nasal bioadhesion, bioadhesive microparticles are used. A bioadhesive formulation for drug administration to the vagina is in use. The gastrointestinal tract is proving a more difficult site because of the rapid turnover of mucus, and relatively constant transit time, but intensive research is in progress. Micro- and nano-particles, coated with either bio/mucoadhesive polymers or specific biological bioadhesives, are showing some promise, but will require considerable research and development before reaching the market.
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Affiliation(s)
- J Woodley
- Laboratoire Cinétique des Xénobiotiques, Faculty of Pharmacy, Toulouse, France.
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Frutos P, Torrado S, Perez-Lorenzo ME, Frutos G. A validated quantitative colorimetric assay for gentamicin. J Pharm Biomed Anal 2000; 21:1149-59. [PMID: 10708399 DOI: 10.1016/s0731-7085(99)00192-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A colorimetric procedure was developed for the quantification of gentamicin. The method was based on the ninhydrin reaction with primary and secondary amines present in the gentamicin. This reaction produces a purple colour. The effects of several factors including pH, ninhydrin concentration and reaction time were investigated to optimize the assay method. Using the assay protocol, the absorption of the gentamicin-ninhydrin mixtures at 400 nm had a linear relationship with the gentamicin concentration ranging from 30 to 120 microg/ml. The colorimetric gentamicin assay reported herein is of great practical value because it is reproducible, sensitive, simple and extremely inexpensive.
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Affiliation(s)
- P Frutos
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Complutense University Madrid, Spain.
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Baeyens V, Kaltsatos V, Boisrame B, Fathi M, Gurny R. Evaluation of soluble Bioadhesive Ophthalmic Drug Inserts (BODI) for prolonged release of gentamicin: lachrymal pharmacokinetics and ocular tolerance. J Ocul Pharmacol Ther 1998; 14:263-72. [PMID: 9671434 DOI: 10.1089/jop.1998.14.263] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The purpose of this investigation was the evaluation of Bioadhesive Ophthalmic Drug Inserts (BODI) for prolonged release of gentamicin sulfate (GS) in tears. The BODIs (length 5.0 mm, diameter 2.0 mm, weight 20.5 mg, average GS content 5.0 mg) were prepared by extrusion of a mixture based on hydroxypropylcellulose (HPC), ethylcellulose (EC) and carbomer. Two methods were tested to prolong the release of GS in tears: (1) preliminary treatment of GS and (2) use of a less hydrophilic polymer than HPC, hydroxypropylmethylcellulose (HPMC), as a vehicle constituent. The preliminary treatment consisted of the formation of a GS/cellulose acetate phthalate (CAP) solid dispersion (ratio GS/CAP: 10/6) made in acetonic medium, and in the coating of GS/EC granules (GS/EC ratio: 10/0.5) with an aqueous dispersion of CAP, to form a GS/EC/CAP coprecipitate (GS/EC/CAP ratio: 10/0.5/6). Inserts containing GS/CAP solid dispersion, GS/EC/CAP coprecipitate and HPMC resulted in improved time of efficacy (t(eff)) (43.8, 23.3, and 33.1 h, respectively), when compared to inserts containing GS without preliminary treatment (t(eff) = 11.9 h). A high irritation level was observed for inserts containing the GS/EC/CAP and HPMC. A relation between t(eff) and irritation score was established, emphasizing the importance of irritability as a factor during the evaluation of the potential of these systems.
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Affiliation(s)
- V Baeyens
- School of Pharmacy, University of Geneva, Switzerland
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Baeyens V, Kaltsatos V, Boisramé B, Varesio E, Veuthey JL, Fathi M, Balant LP, Gex-Fabry M, Gurny R. Optimized release of dexamethasone and gentamicin from a soluble ocular insert for the treatment of external ophthalmic infections. J Control Release 1998; 52:215-20. [PMID: 9685951 DOI: 10.1016/s0168-3659(97)00212-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In the case of external ophthalmic infections, repeated instillations of antibiotics are required to reach therapeutic level, above the minimal inhibitory concentration (MIC). An additional administration of a corticosteroid is often needed, in order to limit the precorneal damages caused by the infection. However, repeated administration of a corticosteroid can increase intraocular pressure and thus lead to glaucoma. To overcome the disadvantages of separated and repeated instillations of two products and to avoid the side effects of dexamethasone, a soluble insert containing gentamicin sulfate and dexamethasone phosphate was developed. The new system ensures the concomitant release of the two drugs during the first 10 h of treatment, followed by an adequate concentration of gentamicin sulfate, above the MIC of 4.0 microgram ml-1, during 50 h, due to a combination of gentamicin sulfate with cellulose acetate phthalate, which reduces the solubility of gentamicin.
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Affiliation(s)
- V Baeyens
- School of Pharmacy, University of Geneva, Switzerland
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