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Şahin E. Enhanced injectability of aqueous β-tricalcium phosphate suspensions through PAA incorporation, gelling and preshearing. J Mech Behav Biomed Mater 2023; 145:106026. [PMID: 37467554 DOI: 10.1016/j.jmbbm.2023.106026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 07/10/2023] [Accepted: 07/13/2023] [Indexed: 07/21/2023]
Abstract
The major shortcoming of aqueous calcium phosphate suspensions used in biomedical applications is their unstable flow during delivery by mechanical means. In this study, microstructural changes and the resulting flow instabilities of aqueous β-TCP suspensions are demonstrated under both pressure-induced and drag-induced flow regimes and then remedied with the incorporation and subsequent gelling and preshearing of Carbopol 940, a biocompatible hydrogel. Mixing and dispersion of calcium phosphate particles into the hydrogel matrix was not efficient under simple agitation conditions. Swelling of the polymer chains was induced at approximately pH = 9.0 by water and particle intrusion within the opened-up coil structure due to deprotonation of the carboxylic acid groups by NaOH. As a result the composite material underwent a rapid viscoplastic transition into a doughy state which was not amenable to further processing without preshearing. Manual kneading converted the material into viscous state and enhanced the flow behavior significantly. Preshearing and probing the microstructure by mechanical spectrometer revealed multiple microstructural mechanisms responsible for the observed stable flow behavior, including improved dispersion of the particles, attrition of the polymeric network into microgel domains, enhanced adhesion and lubrication between the solid and liquid phase, crosslinking of the polymeric network. The net effect of these probable mechanisms was stiffening of the composite matrix, mobilization of solid particles and a marked enhancement in the stability of pressure-induced flow. The resistance of the material to liquid phase migration and its ability to undergo wall-slip and relax under stress were confirmed by simultaneous capillary rheometry and thermogravimetric analyses. The processing method enables improvements in the delivery of this composite material for injection and direct ink writing of scaffolds.
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Affiliation(s)
- Erdem Şahin
- Department of Metallurgical and Materials Engineering, Muğla Sıtkı Koçman University, Turkey.
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Şahin E. Enhanced injectability of aqueous β-tricalcium phosphate suspensions through PAA incorporation, gelling and preshearing. J Mech Behav Biomed Mater 2023; 145:106026. [DOI: https:/doi.org/10.1016/j.jmbbm.2023.106026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/21/2023]
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Abstract
Abstract
The review presents current research results for Carbopol-based microgels as yield-stress materials, covering three aspects: chemical, physical and rheological. Such a joint three-aspect study has no analog in the literature. The chemical aspects of Carbopol polymers are presented in terms of a cross-linking polymerization of acrylic acid, their molecular structure, microgel formulation, polyacid dissociation and neutralization, osmotic pressure and associated immense microgel swelling. The physical characterization is focused on models of the shear-induced solid-to-liquid transition of microgels, which are formed of mesoscopic particles typical for soft matter materials. Models that describe interparticle effects are presented to explain the energy states of microgel particles at the mesoscale of scrutiny. Typical representatives of the models utilize attributes of jamming dispersions, micromechanical and polyelectrolyte reactions. Selected relationships that result from the models, such as scaling rules and nondimensional flow characteristics are also presented. The rheological part presents the discussion of problems of yield stress in 2D and 3D deformations, appearance and magnitude of the wall slip. The theory and characteristics of Carbopol microgel deformation in rotational rheometers are presented with graphs for the steady-state measurements, stress-controlled oscillation and two types of transient shear deformation. The review is concluded with suggestions for future research.
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Affiliation(s)
- Zdzisław Jaworski
- Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology , Aleja Piastow 42 , 71-065 , Szczecin , Poland
| | - Tadeusz Spychaj
- Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology , Aleja Piastow 42 , 71-065 , Szczecin , Poland
| | - Anna Story
- Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology , Aleja Piastow 42 , 71-065 , Szczecin , Poland
| | - Grzegorz Story
- Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology , Aleja Piastow 42 , 71-065 , Szczecin , Poland
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Allmendinger A, Fischer S, Huwyler J, Mahler HC, Schwarb E, Zarraga IE, Mueller R. Rheological characterization and injection forces of concentrated protein formulations: An alternative predictive model for non-Newtonian solutions. Eur J Pharm Biopharm 2014; 87:318-28. [DOI: 10.1016/j.ejpb.2014.01.009] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 01/06/2014] [Accepted: 01/30/2014] [Indexed: 11/25/2022]
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Pisal PB, Patil SS, Pokharkar VB. Rheological investigation and its correlation with permeability coefficient of drug loaded carbopol gel: influence of absorption enhancers. Drug Dev Ind Pharm 2012; 39:593-9. [PMID: 22663597 DOI: 10.3109/03639045.2012.692377] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT The present study was planned to investigate the effect of absorption enhancers on the microstructure of Losartan potassium gel and hence its influence on the diffusion of Losartan potassium across nasal mucosa. METHOD Losartan potassium loaded carbopol gel (1% w/v) with and without absorption enhancers was prepared. Polyethylene glycol (PEG) 4000 and ethanol were used as absorption enhancers. Microstructural elucidation of prepared gels was done using shear rheology. Ex vivo drug release studies were performed on the prepared gels. RESULTS It was observed that the absorption enhancers PEG 4000 and ethanol altered the gel microstructure. The prepared gels were viscoelastic in nature suggesting their suitability for topical application. Permeability coefficient of Losartan potassium loaded into gels was found to be inversely proportional to the storage modulus. Thus increase in storage modulus lead to slow drug diffusion. CONCLUSION The current study emphasizes on the fact that selection of polymeric carrier for nasal drug delivery and/or absorption enhancer strongly influence the microstructure of the gel and hence the pharmaceutical performance of the formulation.
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Affiliation(s)
- Prashant B Pisal
- Department of Pharmaceutics, Poona College of Pharmacy, Bharati Vidyapeeth University, Erandwane, Pune, Maharashtra, India
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Yu T, Malcolm K, Woolfson D, Jones DS, Andrews GP. Vaginal gel drug delivery systems: understanding rheological characteristics and performance. Expert Opin Drug Deliv 2011; 8:1309-22. [DOI: 10.1517/17425247.2011.600119] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kelessidis VC, Hatzistamou V. Preparation Methodology and Rheological Properties of Yield Pseudoplastic Transparent Fluids. J DISPER SCI TECHNOL 2011. [DOI: 10.1080/01932691003662399] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Andrews GP, Donnelly L, Jones DS, Curran RM, Morrow RJ, Woolfson AD, Malcolm RK. Characterization of the rheological, mucoadhesive, and drug release properties of highly structured gel platforms for intravaginal drug delivery. Biomacromolecules 2009; 10:2427-35. [PMID: 19642670 PMCID: PMC2745825 DOI: 10.1021/bm9003332] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/08/2009] [Indexed: 11/28/2022]
Abstract
This investigation describes the formulation and characterization of rheologically structured vehicles (RSVs) designed for improved drug delivery to the vagina. Interactive, multicomponent, polymeric platforms were manufactured containing hydroxyethylcellulose (HEC, 5% w/w) polyvinylpyrrolidone (PVP, 4% w/w), Pluronic (PL, 0 or 10% w/w), and either polycarbophil (PC, 3% w/w) or poly(methylvinylether-co-maleic anhydride) (Gantrez S97, 3% w/w) as a mucoadhesive agent. The rheological (torsional and dynamic), mechanical (compressional), and mucoadhesive properties were characterized and shown to be dependent upon the mucoadhesive agent used and the inclusion/exclusion of PL. The dynamic rheological properties of the gel platforms were also assessed following dilution with simulated vaginal fluid (to mimic in vivo dilution). RSVs containing PC were more rheologically structured than comparator formulations containing GAN. This trend was also reflected in formulation hardness, compressibility, consistency, and syringeability. Moreover, formulations containing PL (10% w/w) were more rheologically structured than formulations devoid of PL. Dilution with simulated vaginal fluids significantly decreased rheological structure, although RSVs still retained a highly elastic structure (G' > G'' and tan delta < 1). Furthermore, RSVs exhibited sustained drug release properties that were shown to be dependent upon their rheological structure. It is considered that these semisolid drug delivery systems may be useful as site-retentive platforms for the sustained delivery of therapeutic agents to the vagina.
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Affiliation(s)
- Gavin P Andrews
- Drug Delivery and Biomaterials Group, The School of Pharmacy, The Queen's University of Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland, United Kingdom.
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Alsarra IA, Hamed AY, Mahrous GM, El Maghraby GM, Al-Robayan AA, Alanazi FK. Mucoadhesive polymeric hydrogels for nasal delivery of acyclovir. Drug Dev Ind Pharm 2009; 35:352-62. [PMID: 18770068 DOI: 10.1080/03639040802360510] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The study evaluated different mucoadhesive polymeric hydrogels for nasal delivery of acyclovir. Gels containing poly-N-vinyl-2-pyrrolidone (PVP) were prepared with crosslinking achieved by irradiation with a radiation dose of 15 kGy being as efficient as 20 kGy. Gels containing chitosan and carbopol were also evaluated. The mucoadhesive properties of gels were measured by a modification of a classical tensile experiment, employing a tensile tester and using freshly excised sheep nasal mucosa. Considering the mucoadhesive force, chitosan gel and gel prepared with 3% PVP in presence of polyethylene glycol (PEG) 600 were the most efficient. The in vitro drug release depended on the gel composition. Higher release rates were obtained from PVP gels compared to chitosan or carbopol gels. The release rate of drug from PVP gels was increased further in presence of PEG or glycerol. Histopathological investigations proved that the PVP was a safe hydrogel to be used for mucosal delivery. The PEG in gel formulations caused less damages to the nasal mucosal compared to formulation containing glycerol.
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Affiliation(s)
- Ibrahim A Alsarra
- Kayyali Chair for Pharmaceutical Industry, Pharmaceutical Technology Center, College of Pharmacy, King Saud University, Riyadh, Kingdom of Saudi Arabia.
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Abstract
Prophylactic efficacy of topical microbicidal drug delivery formulations against HIV may depend upon their abilities to coat and be retained on epithelial surfaces where infection begins. Rheological and surface properties play paramount roles in governing coating. While fundamental fluid mechanical studies of epithelial coating mechanisms have begun, their results have not previously addressed questions of practical value to formulators in the pharmaceutics community. The present theoretical study began this process. We focused upon squeezing flows of seven vaginal gels which are models for future microbicides or a candidate formulation in clinical trials. Each formulation is based upon one of three different macromolecules: cellulose, polyacrylic acid (PAA), or carrageenan. We addressed: (1) properties with greatest influence on squeezing flow; (2) alterations of properties to improve measures of coating dynamics; and (3) effects of polymer concentration and temperature on coating dynamics. We found that yield stresses dominated flows of PAA gels, and that surface slip, while small, significantly influenced coating by cellulose gels. Decreases in consistency, increases in shear-thinning, and increases in temperature led to thinner coatings. Details of altered coating rates depended upon parameter values and time. Specific polymer concentration effects differed between cellulose and PAA gels, though trends were similar.
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Affiliation(s)
- Sarah L Kieweg
- Department of Mechanical Engineering, University of Kansas, Lawrence, Kansas 66045, USA.
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Díez-Sales O, Garrigues TM, Herráez JV, Belda R, Martín-Villodre A, Herráez M. In vitro percutaneous penetration of acyclovir from solvent systems and Carbopol 971-P hydrogels: influence of propylene glycol. J Pharm Sci 2005; 94:1039-47. [PMID: 15793815 DOI: 10.1002/jps.20317] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The mechanism underlying propylene glycol (PG) effects on acyclovir (ACV) penetration through human epidermis were studied. Solvent systems and Carbopol gels containing increasing percentage of PG (from 0% to 70%, w/w) were used. Viscosity studies of both vehicles were carried out to characterise the influence of rheological behaviour. In solvent systems skin permeation values of ACV increase as the concentration of PG increase yielding a maximum enhancement ratio (ER = 10) for 70% PG. The release rate of ACV from gels was determined. Higuchi's model was used to estimate the apparent diffusion coefficient of the drug. These values show a decrease as the content of PG in the vehicle increases; this effect could be attributed to the increase of the viscosity in the diffusional pathway. When gels are used skin permeation values of ACV were smaller than those of the solvent systems. This could be attributed to the network structure created by the polymer that increases the length of the diffusional pathway. The maximum ER (= 6.8) was for Carbopol gel containing 50% PG. Therefore, these gels can be considered candidates for further research to confirm their usefulness as delivery systems for ACV topical formulations.
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Affiliation(s)
- O Díez-Sales
- Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, Valencia, Spain.
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Herráez-Domínguez JV, León FGGD, Díez-Sales O, Herráez-Domínguez M. Rheological characterization of two viscosity grades of methylcellulose: an approach to the modeling of the thixotropic behaviour. Colloid Polym Sci 2005. [DOI: 10.1007/s00396-005-1332-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Jones DS, Muldoon BCO, David Woolfson A, Dominic Sanderson F. Rheological destructuring of aqueous gels composed of cellulose ethers following storage in the presence of redox agents. J Appl Polym Sci 2005. [DOI: 10.1002/app.22180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Baudonnet L, Grossiord J, Rodriguez F. Effect of Dispersion Stirring Speed on the Particle Size Distribution and Rheological Properties of Three Carbomers. J DISPER SCI TECHNOL 2004. [DOI: 10.1081/dis-120030665] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Baudonnet L, Pere D, Michaud P, Grossiord JL, Rodriguez F. Effect of Dispersion Stirring Speed on the Particle Size Distribution and Rheological Properties of Carbomer Dispersions and Gels. J DISPER SCI TECHNOL 2002. [DOI: 10.1081/dis-120014018] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Abstract
A study is made of the polymerization process of polyacrylic acid, commercially known as Carbopol 971 NF, assessing its consistency as a function of the degree of neutralization at pH values from 3 to 12, approximately. Percentage concentrations ranging from 0.1 to 1.4% (w/w) were studied. The gels obtained were non-Newtonian, and pseudoplastic. As concentration and pH rise, the consistency of the gels increase to a maximum, which appears between pH 6 and 8, allowing their use as vehicles in bioadhesive formulations for mucosal application. Over the increasing viscosity interval, functions were obtained to indicate the consistency of the gel as a function of pH and concentration. Since the correlation between the theoretical and experimental results is excellent, the equation found can be used to theoretically calculate the working concentration and pH required to secure the necessary consistency for a given vehicle. The addition of soluble polyvinylpyrrolidone (PVP), and cross-linked PVP (PVPP) does not substantially modify the rheological behavior of the gels, thus permitting their addition to usual vehicles.
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Affiliation(s)
- T Sanz Taberner
- Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Valencia, 46100, Valencia, Burjassot, Spain
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