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Abd-Elaty DM, Ishak RAH, Osman R, Geneidi AS. Engineering a novel water-in-oil biocompatible microemulsion system for the ocular delivery of dexamethasone sodium phosphate in the treatment of acute uveitis. Int J Pharm 2024; 650:123704. [PMID: 38097148 DOI: 10.1016/j.ijpharm.2023.123704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/04/2023] [Accepted: 12/11/2023] [Indexed: 12/18/2023]
Abstract
Due to their unique characteristics, microemulsions (ME) represent one of the most promising delivery systems which can conquer poor ocular drug bioavailability providing long residence time. Development of a ME system, relying on the use of a safe and non-irritant surfactant combination derived from sustainable resources and which can consolidate the small ME droplets, is the goal of this work. Herein, we report the design and characterization of a novel biocompatible, eco-friendly ME system loaded with the hydrophilic dexamethasone sodium phosphate (DEXP) using a novel surfactant mixture composed of D-α-tocopherol polyethylene glycol succinate (TPGS) and Plantacare® (coco-Glycosides). Capryol™ PGMC and double-distilled water were used as the respective oil and aqueous phases and the MEs were prepared by the water titration method, suitable for scaling up. Optimization of ME formulae was conducted by varying Plantacare® grades, TPGS to Plantacare® mass ratios and drug loading. The formulae were characterized in terms of physical appearance, droplet size (PS), size distribution (PDI), zeta potential (ZP), and stability. The optimized DEXP-loaded ME formula attained acceptable PS, PDI, and ZP values of 43 ± 5 nm, 0.35 ± 0.07, -12 ± 4 mV, respectively. TEM images confirmed a small PS ≤ 100 nm. The in vivo safety of ME was proved by the Draize test. The ME formula prompted excellent mucoadhesion and transcorneal permeation. The confocal studies showed deep penetration into the rabbits' corneas. In vivo studies using endotoxin-induced uveitis showed high ocular efficacy and a significant reduction in inflammatory cells, including interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The obtained results elect the novel engineered ME system as a promising tool for the ocular delivery of hydrophilic moieties in the management of various ophthalmic diseases.
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Affiliation(s)
- Dina M Abd-Elaty
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, 11566 Cairo, Egypt
| | - Rania A H Ishak
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, 11566 Cairo, Egypt.
| | - Rihab Osman
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, 11566 Cairo, Egypt
| | - Ahmed S Geneidi
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, 11566 Cairo, Egypt
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Allaboun H, Alkhamis KA, Al-Nimry SS. Preparation of Sustained Release Formulation of Verapamil Hydrochloride Using Ion Exchange Resins. AAPS PharmSciTech 2023; 24:114. [PMID: 37127745 DOI: 10.1208/s12249-023-02569-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 04/17/2023] [Indexed: 05/03/2023] Open
Abstract
The purpose of this investigation was to formulate and evaluate the interaction between cation exchange resins and verapamil hydrochloride. The uptake studies were conducted using the rotating bottle apparatus. The Langmuir-like equation was applied to the experimental data and the maximum drug loading was determined from the Langmuir-like parameters. The drug-resin complexes were evaluated using XRD, SEM, and particle size analysis. Release studies were performed using USP dissolution apparatus 2. The resin with the lowest percentage of cross-linking had the highest uptake capacity. The percent increase in particle size due to complexation was found to be associated with drug loading; the highest drug loading had the highest increase in particle size. The X-ray diffraction patterns of the resins and the drug-resin complexes showed that they were both amorphous. The maximum drug release was approximately 40% when conventional dissolution testing was used. Results showed that sink conditions could not be maintained using conventional dissolution methods. Maximum drug release increased dramatically by increasing the volume of samples withdrawn and fresh dissolution medium added. Excellent correlation was obtained between sample volume and drug release rate with an R-value of 0.988. Particle diffusion-controlled model and film diffusion-controlled model were both applied to the experimental data. The results indicated that the rate-limiting step is the diffusion of the exchanging cations through the liquid film. The modified release formulation was prepared successfully and correlated very well with the USP monograph for verapamil hydrochloride extended release capsules.
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Affiliation(s)
- Hussein Allaboun
- Department of Chemical Engineering, Faculty of Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Khouloud A Alkhamis
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan.
| | - Suhair S Al-Nimry
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan
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In vitro evaluation of antibacterial activity and biocompatibility of synergistically cross-linked gelatin-alginate hydrogel beads as gentamicin carriers. J Drug Deliv Sci Technol 2023. [DOI: 10.1016/j.jddst.2022.104078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Abstract
Carriers are protective transporters of drugs to target cells, facilitating therapy under each points of view, such as fast healing, reducing infective phenomena, and curing illnesses while avoiding side effects. Over the last 60 years, several scientists have studied drug carrier properties, trying to adapt them to the release environment. Drug/Carrier interaction phenomena have been deeply studied, and the release kinetics have been modeled according to the occurring phenomena involved in the system. It is not easy to define models’ advantages and disadvantages, since each of them may fit in a specific situation, considering material interactions, diffusion and erosion phenomena, and, no less important, the behavior of receiving medium. This work represents a critical review on main mathematical models concerning their dependency on physical, chemical, empirical, or semi-empirical variables. A quantitative representation of release profiles has been shown for the most representative models. A final critical comment on the applicability of these models has been presented at the end. A mathematical approach to this topic may help students and researchers approach the wide panorama of models that exist in literature and have been optimized over time. This models list could be of practical inspiration for the development of researchers’ own new models or for the application of proper modifications, with the introduction of new variable dependency.
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Effect of Formulation Variables on the Performance of Doxycycline-Loaded PLA Microsphere. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2020. [DOI: 10.1007/s13369-020-04592-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Jayanudin, Fahrurrozi M, Wirawan SK, Rochmadi. Preparation of Chitosan Microcapsules Containing Red Ginger Oleoresin Using Emulsion Crosslinking Method. J Appl Biomater Funct Mater 2019; 17:2280800018809917. [PMID: 30803278 DOI: 10.1177/2280800018809917] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND: Encapsulation is one of the methods used to trap active ingredients in the wall material of microparticles. AIM: The aim of this study was to evaluate the encapsulation of red ginger oleoresin using an emulsion crosslinking method with chitosan as the wall material. METHODS: Emulsions were formed of red ginger oleoresin with chitosan in concentrations of 1%, 2%, 3%, and 4% (w/v), respectively. The emulsions were then mixed with corn oil and stirred for one hour to obtain a second set of emulsions, and glutaraldehyde saturated toluene (GST) was added dropwise in quantities of 20, 10, 6.7, and 5 ml, respectively. This was followed by the addition of 2 ml of 25% glutaraldehyde and the emulsions were stirred for two hours. The resulting microcapsules were washed with petroleum ether followed by hexane and then dried in an oven at 70oC. RESULTS: The emulsion crosslinking method used to trap the red ginger oleoresin in chitosan produced microcapsules of good spherical geometry with the mean diameter ranging from 75.61 ± 11.8 µm to 178.65 ± 40.7 µm. The highest yield was 98.93% and encapsulation efficiency was 83.1%. Thermogravimetric and differential thermal analysis showed that the melting point was at a temperature between 120 and 130oC. CONCLUSION: Chitosan concentration has little effect on encapsulation yield, whereas the amount of GST tends to strengthen the crosslinking bonds of chitosan and reduces the mean diameter of microspheres.
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Affiliation(s)
- Jayanudin
- 1 Chemical Engineering Department, Faculty of Engineering, Universitas Gadjah Mada, Indonesia
- 2 Chemical Engineering Department, Faculty of Engineering, Universitas Sultan Ageng Tirtayasa, Indonesia
| | - Moh Fahrurrozi
- 1 Chemical Engineering Department, Faculty of Engineering, Universitas Gadjah Mada, Indonesia
| | - Sang Kompiang Wirawan
- 1 Chemical Engineering Department, Faculty of Engineering, Universitas Gadjah Mada, Indonesia
| | - Rochmadi
- 1 Chemical Engineering Department, Faculty of Engineering, Universitas Gadjah Mada, Indonesia
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Gracia R, Yus C, Abian O, Mendoza G, Irusta S, Sebastian V, Andreu V, Arruebo M. Enzyme structure and function protection from gastrointestinal degradation using enteric coatings. Int J Biol Macromol 2018; 119:413-422. [DOI: 10.1016/j.ijbiomac.2018.07.143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 12/18/2022]
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Novel NGR anchored pullulan micelles for controlled and targeted delivery of doxorubicin to HeLa cancerous cells. IRANIAN POLYMER JOURNAL 2018. [DOI: 10.1007/s13726-018-0606-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Pandit AP, Patel SA, Bhanushali VP, Kulkarni VS, Kakad VD. Nebivolol-Loaded Microsponge Gel for Healing of Diabetic Wound. AAPS PharmSciTech 2017; 18:846-854. [PMID: 27357423 DOI: 10.1208/s12249-016-0574-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/13/2016] [Indexed: 01/07/2023] Open
Abstract
An attempt was made to formulate nebivolol-loaded microsponge gel to access drug at wound area, incorporated into gel that possess optimum moist wound management environment during later stages of wound closure. Nebivolol, antihypertensive drug, exhibits vasodilating effects via nitric oxide pathway, slows diabetic neuropathy, and restores endothelial function in diabetic wounds. Microsponges were prepared by optimizing independent variables; drug to polymer ratio and internal phase volume and their effects on production yield, entrapment efficiency, and particle size. Formulations of microsponges were evaluated for drug content. Differential scanning calorimetry indicated reduction in crystallinity of NB during the formation of microsponges. In vitro study (drug to polymer 1:4 and 10 ml internal phase volume acetone) showed 80% drug released within 8 h. Spherical and porous microsponges confirmed by scanning electron microscopy were incorporated in the carbopol 934 (2%) gel base. Gel was characterized for pH, viscosity, and drug content. Less spreadability determined by texture analyzer demonstrated viscous nature of gel. In vitro diffusion study revealed entrapped drug in porous microsponges with slow release to heal wound. In vivo study performed using streptozotocin-induced diabetic rats and excision wound model showed wound healing and closure activity within day 10. Histology revealed inflammatory cell infiltrations and neovascularization in granulation tissues, ultimately healing wound. Microsponge gel prolonged drug release due to entrapped form in porous structure of microsponges with significant and fast wound healing and closure in diabetic rats. Microsponges with loaded drug fulfilled accessibility at wound area, while gel provided optimum moist wound management environment during later stages of wound closure.
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Ahmed TA, El-Say KM. Transdermal film-loaded finasteride microplates to enhance drug skin permeation: Two-step optimization study. Eur J Pharm Sci 2016; 88:246-56. [DOI: 10.1016/j.ejps.2016.03.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 03/09/2016] [Accepted: 03/14/2016] [Indexed: 12/20/2022]
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Effect of binders on the release rates of direct molded verapamil tablets using twin-screw extruder in melt granulation. Int J Pharm 2014; 463:89-97. [PMID: 24406670 DOI: 10.1016/j.ijpharm.2013.12.053] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 12/04/2013] [Accepted: 12/27/2013] [Indexed: 11/21/2022]
Abstract
Conventional manufacturing of pharmaceutical tablets often involves single processes such as blending, granulation, milling and direct compression. A process that minimizes and incorporates all these in a single continuous step is desirable. The concept of omitting milling step followed by direct-molding of tablets utilizing a twin-screw extruder in a melt granulation process using thermoplastic binders was explored. The objective of this study was to investigate the effect of combining hydrophilic binder (HPMC K4M, PEO 1M), and hydrophobic binder (Compritol® ATO 888, Precirol® ATO 5) on the release profiles of direct-molded tablets and direct-compressed tablets from milled extrudates using a quality-by-design approach. It was identified that hydrophilic binder type and process significantly affects (p=0.005) the release profiles of verapamil. Moreover, two-way interaction analysis demonstrated that the combination of process with type of hydrophilic polymer (p=0.028) and the type of hydrophilic polymer with polymer ratio (p=0.033) significantly affected the release profiles. The formulation release kinetics correlated to Higuchi release model and the mechanism correlated to a non-Fickian release mechanism. The results of the present study indicated that direct-molded tablets with different release profiles can be manufactured without milling process and through a continuous melt granulation using twin-screw extruder with appropriate thermoplastic binder ratio.
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Thakare M, Israel B, Garner ST, Ahmed H, Garner P, Elder D, Price JC, Capomacchia AC. Formulation parameters and release mechanism of theophylline loaded ethyl cellulose microspheres: effect of different dual surfactant ratios. Pharm Dev Technol 2011; 18:1213-9. [DOI: 10.3109/10837450.2011.620969] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Zaki Rizkalla CM, latif Aziz R, Soliman II. In vitro and in vivo evaluation of hydroxyzine hydrochloride microsponges for topical delivery. AAPS PharmSciTech 2011; 12:989-1001. [PMID: 21800216 DOI: 10.1208/s12249-011-9663-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 06/30/2011] [Indexed: 11/30/2022] Open
Abstract
Hydroxyzine HCl is used in oral formulations for the treatment of urticaria and atopic dermatitis. Dizziness, blurred vision, and anticholinergic responses, represent the most common side effects. It has been shown that controlled release of the drug from a delivery system to the skin could reduce the side effects while reducing percutaneous absorption. Therefore, the aim of the present study was to produce an effective drug-loaded dosage form that is able to control the release of hydroxyzine hydrochloride into the skin. The Microsponge Delivery System is a unique technology for the controlled release of topical agents, and it consists of porous polymeric microspheres, typically 10-50 μm in diameter, loaded with active agents. Eudragit RS-100 microsponges of the drug were prepared by the oil in an oil emulsion solvent diffusion method using acetone as dispersing solvent and liquid paraffin as the continuous medium. Magnesium stearate was added to the dispersed phase to prevent flocculation of Eudragit RS-100 microsponges. Pore inducers such as sucrose and pregelatinized starch were used to enhance the rate of drug release. Microsponges of nearly 98% encapsulation efficiency and 60-70% porosity were produced. The pharmacodynamic effect of the chosen preparation was tested on the shaved back of histamine-sensitized rabbits. Histopathological studies were driven for the detection of the healing of inflamed tissues.
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Patil SB, Sawant KK. Development, optimization and in vitro evaluation of alginate mucoadhesive microspheres of carvedilol for nasal delivery. J Microencapsul 2011; 26:432-43. [PMID: 18932060 DOI: 10.1080/02652040802456726] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The present research work was aimed at development and optimization of alginate mucoadhesive microspheres of carvedilol for nasal delivery to avoid first pass metabolism and to improve the therapeutic efficacy in the treatment of hypertension and angina pectoris. The microspheres were prepared by a water-in-oil (w/o) emulsification technique. A 2(3) factorial design was employed with drug : polymer ratio, calcium chloride concentration and cross-linking time as independent variables while particle size of the microspheres and in vitro mucoadhesion were the dependent variables. Regression analysis was performed to identify the best formulation conditions. Particle size was analysed by dynamic laser light diffraction technique and found to be in the range of 26.36-54.32 microm, which is favourable for intranasal absorption. The shape and surface characteristics were determined by scanning electron microscopy (SEM) which depicted the spherical nature and nearly smooth surfaces of the microspheres. The percentage encapsulation efficiency was found to be in the range between 36.62-56.18. In vitro mucoadhesion was performed by adhesion number using sheep nasal mucosa and was observed in a range from 69.25-85.28. Differential scanning calorimetry and X-ray diffraction results indicated a molecular level dispersion of carvedilol in the microspheres. In vitro release studies in pH 6.2 phosphate buffer indicated non-Fickian or anomalous type of transport for the release of carvedilol from the microspheres.
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Affiliation(s)
- Sanjay B Patil
- New Drug Delivery Research Laboratory, TIFAC Center of Relevance and Excellence in NDDS, Pharmacy Department, The M. S. University of Baroda, Fatehgunj, Vadodara, Gujarat, India
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Zaky A, Elbakry A, Ehmer A, Breunig M, Goepferich A. The mechanism of protein release from triglyceride microspheres. J Control Release 2010; 147:202-10. [DOI: 10.1016/j.jconrel.2010.07.110] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 07/14/2010] [Accepted: 07/17/2010] [Indexed: 10/19/2022]
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Jelvehgari M, Barar J, Valizadeh H, Shadrou S, Nokhodchi A. Formulation, characterization and in vitro evaluation of theophylline-loaded Eudragit RS 100 microspheres prepared by an emulsion-solvent diffusion/evaporation technique. Pharm Dev Technol 2010; 16:637-44. [DOI: 10.3109/10837450.2010.508075] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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17
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Pattnaik S, Kalpana S, Choudhury P, Acharya PK, Mallick S. Alfuzosin hydrochloride transdermal films: evaluation of physicochemical, in vitro human cadaver skin permeation and thermodynamic parameters. Int Braz J Urol 2009; 35:716-29. [DOI: 10.1590/s1677-55382009000600010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2009] [Indexed: 11/21/2022] Open
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Duvvuri S, Gaurav Janoria K, Mitra AK. Effect of polymer blending on the release of ganciclovir from PLGA microspheres. Pharm Res 2006; 23:215-23. [PMID: 16320000 DOI: 10.1007/s11095-005-9042-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2005] [Accepted: 10/05/2005] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of the study is to investigate the effect of polymer blending on entrapment and release of ganciclovir (GCV) from poly(D,L-lactide-co-glycolide) (PLGA) microspheres using a set of empirical equations. METHODS Two grades of PLGA, PLGA 7525 [D,L-lactide:glycolide(75:25), MW 90,000-126,000 Da] and Resomer RG 502H [D,L-lactide:glycolide(50:50), MW 8000 Da], were employed in the preparation of PLGA microspheres. Five sets of microsphere batches were prepared with two pure polymers and their 1:3, 1:1, and 3:1 blends. Drug entrapment, surface morphology, particle size analysis, drug release, and differential scanning calorimetric studies were performed. In vitro drug-release data were fitted to a set of empirical sigmoidal equations by nonlinear regression analysis that could effectively predict various parameters that characterize both diffusion and degradation cum diffusion-controlled release phases of GCV. RESULTS Entrapment efficiencies of GCV ranged from 47 to 73%. Higher amounts of GCV were entrapped in polymer blend microspheres relative to individual polymers. Triphasic GCV release profiles were observed, which consisted of both diffusion and degradation cum diffusion-controlled phases. In vitro GCV release was shortest for Resomer RG 502H microsphere (10 days) and longest for PLGA 7525 microspheres (90 days). Upon blending, the duration of release gradually decreased as the content of Resomer RG 502H in the matrix was raised. Equations effectively estimated the drug-release rate constants during both the phases with high R2 values (>0.990). GCV release was slower from the blend microsphere during the initial diffusion phase. Majority of entrapped drug (70-95%) was released during the matrix degradation cum diffusion phase. CONCLUSIONS Drug entrapment and release parameters estimated by the equations indicate more efficient matrix packing between PLGA 7525 and Resomer RG 502H in polymer-blended microspheres. The overall duration of drug release diminishes with rising content of Resomer RG 502H in the matrix. Differential scanning calorimetry studies indicate stronger binding between the polymers in the PLGA 7525/Resomer RG 502HColon, two colons 3:1 blend. Polymer blending can effectively alter drug-release rates of controlled delivery systems in the absence of any additives.
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Affiliation(s)
- Sridhar Duvvuri
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005, Rockhill Road, Kansas City, Missouri 64110, USA
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Sankalia MG, Mashru RC, Sankalia JM, Sutariya VB. Physicochemical characterization of papain entrapped in ionotropically cross-linked kappa-carrageenan gel beads for stability improvement using Doehlert shell design. J Pharm Sci 2006; 95:1994-2013. [PMID: 16850431 DOI: 10.1002/jps.20665] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This work examines the influence of various process parameters on papain entrapped in cross-linked kappa-carrageenan beads for improvement of its stability. A Doehlert shell design (DSD) was employed to investigate the effect of three process variables, namely kappa-carrageenan concentration, KCl concentration, and hardening time, on the entrapment, time required for 50% enzyme release (T50), time required for 90% enzyme release (T90), and particle size. The beads were prepared by dropping the kappa-carrageenan containing papain into a magnetically stirred KCl solution. Topographical characterization was carried out by scanning electron microscopy and entrapment was confirmed by Fourier transform infrared spectroscopy and differential scanning calorimetry. Stability testing was carried out according to the International Conference on Harmonization (ICH) guidelines for zone III and IV. A polymeric matrix was prepared with kappa-carrageenan (3.5% w/v) and potassium chloride (0.5 M) using the ionotropic gelation method, with a hardening time of 20 min. Beads characterized by a spherical disc shape with a collapsed center, an absence of aggregates, an entrapment of 82.75%, a T90 value of 55.36 min, and a composite index of 88.55 were produced. The shelf-life of the enzyme-loaded beads was found to increase to 3.63 years compared with 1.01 years for the conventional formulation. It can be inferred that the proposed methodology can be used to prepare papain-loaded kappa-carrageenan beads for stability improvement.
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Affiliation(s)
- Mayur G Sankalia
- Pharmacy Department, Centre of Relevance and Excellence in Novel Drug Delivery Systems, G. H. Patel Building, Donor's Plaza, The M. S. University of Baroda, Vadodara 390 002, India.
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Sankalia MG, Mashru RC, Sankalia JM, Sutariya VB. Stability improvement of alpha-amylase entrapped in kappa-carrageenan beads: Physicochemical characterization and optimization using composite index. Int J Pharm 2006; 312:1-14. [PMID: 16500055 DOI: 10.1016/j.ijpharm.2005.11.048] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Revised: 11/01/2005] [Accepted: 11/24/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE This work examines the influence of various process parameters on alpha-amylase entrapped in crosslinked kappa-carrageenan beads for stability improvement. A three level full factorial design was employed to investigate the effect of three process variables namely kappa-carrageenan concentration, potassium chloride concentration and hardening time on % entrapment, time required for 50% (T50) and 90% (T90) of enzyme release and particle size. METHODS The beads were prepared by dropping the kappa-carrageenan-containing alpha-amylase to magnetically stirred potassium chloride solution. The composite index was applied to optimize the process under study. 'In vitro' enzyme release profile of the beads was fitted to various release kinetics models to understand the release mechanism. Topographical characterization was carried out by SEM and entrapment was confirmed by FTIR and DSC. Stability testing according to the ICH guidelines for zone III and IV was carried out. RESULTS With the use of ionotropic gelation method, a polymeric matrix prepared by 3.5% (w/v) kappa-carrageenan, 0.7 M potassium chloride and hardening time of 30 min resulted in the production of beads characterized by disc shaped with collapsed center, absence of aggregates, % entrapment of 73.79, T90 of 74.4 min, and composite index of 83.01. Moreover, shelf-life of the enzyme loaded beads was found to increase up to 3.53 years compared to 0.99 year of the conventional formulation. CONCLUSIONS It can be inferred that the proposed method can be used to prepare alpha-amylase loaded kappa-carrageenan beads for stability improvement. Also the proper selection of rate-controlling carrageenan concentration and its interactive potential for crosslinking is important and will determine the overall size and shape of beads, the duration and pattern of dissolution profiles and enzyme loading capacity.
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Affiliation(s)
- Mayur G Sankalia
- Centre of Relevance and Excellence in Novel Drug Delivery Systems, Pharmacy Department, G.H. Patel Building, The M.S. University of Baroda, Vadodara 390002, India.
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iHoroz BB, Kliçarslan M, Yüksel N, Baykara T. Influence of aluminum tristearate and sucrose stearate as the dispersing agents on physical properties and release characteristics of eudragit RS microspheres. AAPS PharmSciTech 2006; 7:E111-E117. [PMID: 16584146 PMCID: PMC2750723 DOI: 10.1208/pt070116] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Accepted: 12/29/2005] [Indexed: 11/30/2022] Open
Abstract
The purpose of this research was to investigate the effects of different concentrations of polymer and sucrose stearate, aluminum tristearate as dispersing agents on microsphere properties and performance. The yield values of microspheres were over the 78%, and the encapsulation efficiencies were found to be approximately 73%. Particle sizes of microspheres prepared with aluminum tristearate were between 76 and 448 microm, while that of the microspheres containing sucrose stearate were between 521 and 2000 microm. Morphological and physicochemical properties of microspheres were investigated by scanning electron micrography and differential scanning calorimetry (DSC). DSC analysis indicated that verapamil hydrochloride formed a solid solution with acrylic polymers. In vitro release studies were performed using the flow-through cell method. While approximately 80% of drug was released from the microspheres containing aluminum tristearate in 480 minutes, the same amount of drug was released from microspheres containing sucrose stearate in only 60 minutes. Chemical structures and concentrations of the dispersing agents were clearly effective on the physical properties of microspheres and their drug-release characteristics.
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Affiliation(s)
- B Bahar iHoroz
- Ankara University Faculty of Pharmacy, Department of Pharmaceutical
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Duvvuri S, Janoria KG, Mitra AK. Development of a novel formulation containing poly(d,l-lactide-co-glycolide) microspheres dispersed in PLGA-PEG-PLGA gel for sustained delivery of ganciclovir. J Control Release 2005; 108:282-93. [PMID: 16229919 DOI: 10.1016/j.jconrel.2005.09.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 08/30/2005] [Accepted: 09/01/2005] [Indexed: 11/23/2022]
Abstract
The purpose of this work is to develop empirical equations for describing the in vitro ganciclovir (GCV) release from PLGA microspheres and also to develop and characterize a formulation containing GCV loaded PLGA microspheres dispersed in thermogelling PLGA-PEG-PLGA polymer gel. Effect of polymer chain length and polymer blending on GCV entrapment and release from PLGA microspheres is also examined. PLGA microspheres of GCV were prepared from two polymers PLGA 6535 (d,l-lactide:glycolideColon, two colons65:35, Mw=45,000-75,000 Da) and Resomer RG 502H (d,l-lactide:glycolideColon, two colons50:50, Mw=8000 Da) and a 3:1 mixture. PLGA-PEG-PLGA polymer was synthesized and characterized. In vitro GCV release studies were conducted with microspheres and microspheres dispersed in 23% w/v PLGA-PEG-PLGA solution. Polymer blended microspheres entrap more GCV (72.67+/-2.49%) than both PLGA 6535 (51.37+/-2.7%) and Resomer RG 502H (47.13+/-1.13%) microspheres. In vitro drug release data was fit to sigmoid equations and release parameters were estimated by nonlinear regression analysis. These equations effectively describe three different phases in GCV release from PLGA microspheres, initial diffusion, matrix hydration and degradation. The amount of drug release during the initial phase decreased for the blend microspheres indicating efficient packing between the PLGA 6535 and Resomer RG 502H in the microsphere matrix. Moreover, upon dispersion into the polymer gel, the rate of drug release during initial diffusion phases slowed relative to microspheres alone. In conclusion, this study reports the development of PLGA microspheres with high payloads and their PLGA-PEG-PLGA gel based formulations. Drug release equations have been developed that effectively describe the triphasic GCV release.
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Affiliation(s)
- Sridhar Duvvuri
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 5005, Rockhill road, Kansas City, MO 64110, USA
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Passerini N, Perissutti B, Albertini B, Voinovich D, Moneghini M, Rodriguez L. Controlled release of verapamil hydrochloride from waxy microparticles prepared by spray congealing. J Control Release 2003; 88:263-75. [PMID: 12628333 DOI: 10.1016/s0168-3659(03)00009-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this work, the potential of waxes for preparing with the ultrasonic spray congealing technique microparticles for controlling the in vitro release of verapamil HCl was investigated. The first part of the study encompassed the optimisation of the formulation to achieve an efficient drug incorporation together with a satisfactory in vitro drug release rate. In particular, microcrystalline wax, stearyl alcohol and mixtures of the two were used. Also a surfactant (soya lecithin) was added to the formulations. After the particle size analysis, the characterisation of the microparticles involved the study of the solid state of drug and carriers in the systems (DSC, HSM and XRD) and the morphological and chemical analyses of the microparticle surface (SEM and XPS). Finally, the drug release mechanism from these devices was evaluated using the statistical moment analysis. The results of this study show that by selecting the type and the amount of the carriers, microparticles with a spherical shape and a good encapsulation efficiency were observed. These particles showed a zero-order release for 8 h, without modifying the solid state properties of the drug. Therefore, waxy microparticles prepared by the ultrasonic spray congealing technique are promising solvent-free devices for controlling the release of verapamil HCl.
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Affiliation(s)
- Nadia Passerini
- Department of Pharmaceutical Sciences, University of Bologna, Via S. Donato 19/2, Italy.
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24
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Liu J, Chan SY, Ho PC. Polymer-coated microparticles for the sustained release of nitrofurantoin. J Pharm Pharmacol 2002; 54:1205-12. [PMID: 12356274 DOI: 10.1211/002235702320402044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Suspensions of nitrofurantoin (NTF) microparticles for controlled release were investigated in this study. The microparticles were enteric coated with various combinations of the two polymers, cellulose acetate phthalate/cellulose acetate butyrate (CAP/CAB) by a modified solvent evaporation method. Ratios of NTF to the two polymers (NTF/CAP/CAB) ranged from 1.0:1.6:0.4,1.0:1.0:1.0,1.0: 0.4:1.6 to 1.0:0.0:2.0. The encapsulation efficiency, percentage yield, determined by comparing the final mass of the microparticles with the initial mass of the ingredients used, distribution of particle size and the in-vitro dissolution profiles of the microparticles were determined. Based on light photographs for the evaluation of the microparticle morphology, the drug crystals appeared to be encapsulated sufficiently by the enteric polymers. In our study, the microparticles enteric coated with CAP/CAB in the ratio of 0.4:1.6 displayed the most satisfactory in-vitro release profile (reduced release in the simulated gastric fluid and sustained release in the simulated intestinal fluid). Thus, microparticles with NTF/CAP/CAB in the ratio of 1.0:0.4:1.6 were formulated into a suspension for further bioavailability and ulcerogenicity studies in Sprague-Dawley rats, with the suspension of NTF crystals as a control. The bioavailability study was carried out in eight rats fed with either the free NTF or the corresponding microparticles in a cross-over design. The ulcerogenicity study was carried out in three groups of six rats each: one group received no drug treatment; the control group was treated with free NTF; and the third group was treated with enteric-coated NTF microparticles. The bioavailability of NTF from the microparticles was comparable with the control. More importantly, there was notably less ulceration of the gastric mucosa observed after dosing with the microparticle suspension compared with that after the administration of the control suspension.
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Affiliation(s)
- Jita Liu
- Department of Pharmacy, National University of Singapore, Republic of Singapore
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Sipahigil O, Dortunç B. Preparation and in vitro evaluation of verapamil HCl and ibuprofen containing carrageenan beads. Int J Pharm 2001; 228:119-28. [PMID: 11576774 DOI: 10.1016/s0378-5173(01)00814-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The objective of this study was to prepare and evaluate carrageenan beads as a controlled release system for a freely water soluble drug verapamil hydrochloride and a slightly water soluble drug ibuprofen. Beads were prepared by ionotropic gelation method. The influence of formulation factors (drug content, polymer concentration, counterion type and concentration, outer phase volume) on the particle size, encapsulation efficiency and in vitro release characteristics of beads was investigated. The encapsulation efficiency of veraparnil HCl in the beads (34.8-71.1%) was higher than that of ibuprofen (23.6-58%). While about 30% of ibuprofen was released at 6 h, about 70% of verapamil HCl was released in 5 h from the carrageenan beads prepared.
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Affiliation(s)
- O Sipahigil
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Marmara University, Haydarpaşa, 81010, Istanbul, Turkey
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26
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Sereti V, Stamatis H, Pappas C, Polissiou M, Kolisis F. Enzymatic acylation of hydroxypropyl cellulose in organic media and determination of ester formation by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Biotechnol Bioeng 2001; 72:495-500. [PMID: 11180070 DOI: 10.1002/1097-0290(20010220)72:4<495::aid-bit1012>3.0.co;2-t] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Esters were prepared by acylation of hydroxypropyl cellulose with fatty acid catalyzed by immobilized lipase from Candida antarctica in tert-butanol. The nature of the substrates used, the initial water activity of the system, and the molecular weight of the hydroxypropyl cellulose were investigated. Moreover, Fourier transform-infrared (FT-IR) spectroscopy was used for determination of ester content on hydroxypropyl cellulose. Specifically, a linear relationship was established between the peak height assigned to the absorption of the esterified carboxyl groups of the cellulose and the ester content. At optimum reaction conditions, the ester content on the hydroxypropyl cellulose was about 11%.
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Affiliation(s)
- V Sereti
- Biotechnology Laboratory, Chemical Engineering Department, Division IV, National Technical University of Athens, 9 Iroon Polytechniou, Zografou Campus, 15700 Athens, Greece
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KONDO T. Microcapsules. Their Science and Technology. Part III. Industrial, Medical, and Pharmaceutical Applications. J Oleo Sci 2001. [DOI: 10.5650/jos.50.143] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Lewis KJ, Irwin WJ, Akhtar S. Development of a sustained-release biodegradable polymer delivery system for site-specific delivery of oligonucleotides: characterization of P(LA-GA) copolymer microspheres in vitro. J Drug Target 1998; 5:291-302. [PMID: 9713978 DOI: 10.3109/10611869808995882] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Development of a Sustained-Release Biodegradable Polymer Delivery System for Site-Specific Delivery of Oligonucleotides: Characterization of P(LA-GA) Copolymer Microspheres In Vitro Antisense oligodeoxynucleotides (ODNs) can selectively inhibit individual gene expression provided they gain access to and remain stable at the target site for a sufficient period of time. Biodegradable sustained-release delivery systems may facilitate site-specific delivery and also prevent degradation of ODNs by nucleases whilst delivering the nucleic acid in a controlled manner to the desired site of action. In this study, we have characterized biodegradable poly (lactide-co-glycolide) (P(LA-GA)) 50:50 microspheres for the potential delivery of antisense oligonucleotides in vivo. Phosphodiester (PO) oligonucleotides complementary to either c-myc proto-oncogene or the tat gene in HIV-RNA were adequately incorporated within P(LA-GA) microspheres with entrapment efficiencies up to 60% depending on particles size. In vitro release profiles of antisense nucleic acids from 10-20 microm size microspheres over 56 days in physiological buffer were triphasic. Profiles were characterised by an initial burst effect during the first 48 hours (phase 1) of release followed by a more sustained release (phase 2) with an additional increased release (phase 3) being observed after 25 days which corresponded with bulk degradation of the copolymer matrix. The release profiles were influenced by microsphere size, copolymer molecular weight, ODN loading, ODN length and by the pH of release medium used. The serum stability of PO ODNs was significantly improved when entrapped within P(LA-GA) microspheres and the hybridization capability, as assessed by duplex melting (Tm) measurements, of released ODN was not impaired by the double-emulsion microsphere fabrication procedure used. Thus, P(LA-GA) microspheres appear to be promising candidates for improving site-specific delivery profiles for ODNs and are worthy of further evaluation in vivo.
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Affiliation(s)
- K J Lewis
- Pharmaceutical Sciences Institute, Aston University, Birmingham, UK
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