Development of Bisphosphonate-Calcium Phosphate Composites and Drug Release Characteristic

2012 ◽  
Vol 1418 ◽  
Author(s):  
Hidekuni Kameda ◽  
Tomohiko Yoshioka ◽  
Toshiyuki Ikoma ◽  
Junzo Tanaka
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Drug Carrier ◽  
Phosphate Buffer Solution ◽  
Octacalcium Phosphate ◽  
Acetate Buffer Solution ◽  
Unit Weight ◽  
Unit Surface Area ◽  
Acetate Solution ◽  
Buffer Solution

ABSTRACTBisphosphonate (Bp) was adsorbed on the surface of crystalline calcium phosphates (CP); hydroxyapatite (HAp), octacalcium phosphate (OCP) and Dicalcium phosphate dehydrate (DCPD). The amount of Bp adsorbed was the largest for DCPD per unit surface area, while the amount was the largest for HAp per unit weight. The composites of Bp and amorphous calcium phosphate (ACP) were synthesized by titrating calcium acetate solution into phosphate buffer solution containing Bp. The amount of Bp doped in the composites was 366 μg / mg and was approximately 7 times larger than those of Bp adsorbed on the crystalline Calcium phosphates. TG-DTA measurements of a Bp-calcium and the composite indicated exothermic peaks due to Bp combustion, of which temperature were shifted to higher temperature for the composite. Bp in the composites was gradually released into phosphate buffered saline, while Bp was rapidly released into acetate buffer solution accompanied with the dissolution of ACP. This result suggests that the composite of Bp and ACP has potential for a drug-carrier releasing Bp in response to the condition of osteoclastic bone resorption.

scholarly journals Preparation, Characterization, and In Vitro Evaluation of Resveratrol-Loaded Cellulose Aerogel

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1624
Author(s):  
Lili Qin ◽  
Xinyu Zhao ◽  
Yiwei He ◽  
Hongqiang Wang ◽  
Hanjing Wei ◽  
...  
Keyword(s):  
High Speed ◽  
Drug Carrier ◽  
Phosphate Buffer Solution ◽  
Gastric Fluid ◽  
Simulated Gastric Fluid ◽  
Oxidized Cellulose ◽  
Buffer Solution ◽  
Aggregation State ◽  
Cellulose Aerogel

Resveratrol is a natural active ingredient found in plants, which is a polyphenolic compound and has a variety of pharmaceutical uses. Resveratrol-loaded TEMPO-oxidized cellulose aerogel (RLTA) was prepared using a freeze-drying method, employing high speed homogenization followed by rapid freezing with liquid nitrogen. RLTAs were designed at varying drug–cellulose aerogel ratios (1:2, 2:3, 3:2, and 2:1). It could be seen via scanning electron microscopy (SEM) that Res integrated into TEMPO-oxidized cellulose (TC) at different ratios, which changed its aggregation state and turned it into a short rod-like structure. Fourier transform infrared (FTIR) spectra confirmed that the RLTAs had the characteristic peaks of TC and Res. In addition, X-ray diffraction (XRD) demonstrated that the grain size of RLTA was obviously smaller than that of pure Res. RLTAs also had excellent stability in both simulated gastric fluid and phosphate buffer solution. The drug release rate was initially completed within 5 h under a loading rate of 30.7 wt%. The results of an MTT assay showed the low toxicity and good biocompatibility of the RLTAs. TC aerogel could be a promising drug carrier that may be widely used in designing and preparing novel biomedicine.

scholarly journals A New Type of Biphasic Calcium Phosphate Cement as a Gentamicin Carrier for Osteomyelitis

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Wen-Yu Su ◽  
Yu-Chun Chen ◽  
Feng-Huei Lin
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Biphasic Calcium Phosphate ◽  
Setting Time ◽  
Phosphate Buffer Solution ◽  
Infrared Spectrometry ◽  
Final Phase ◽  
Buffer Solution ◽  
Alternative Treatment Option ◽  
High Doses

Osteomyelitis therapy is a long-term and inconvenient procedure for a patient. Antibiotic-loaded bone cements are both a complementary and alternative treatment option to intravenous antibiotic therapy for the treatment of osteomyelitis. In the current study, the biphasic calcium phosphate cement (CPC), calledα-TCP/HAP (α-tricalcium phosphate/hydroxyapatite) biphasic cement, was prepared as an antibiotics carrier for osteomyelitis. The developed biphasic cement with a microstructure ofα-TCP surrounding the HAP has a fast setting time which will fulfill the clinical demand. The X-ray diffraction and Fourier transform infrared spectrometry analyses showed the final phase to be HAP, the basic bone mineral, after setting for a period of time. Scanning electron microscopy revealed a porous structure with particle sizes of a few micrometers. The addition of gentamicin inα-TCP/HAP would delay the transition ofα-TCP but would not change the final-phase HAP. The gentamicin-loadedα-TCP/HAP supplies high doses of the antibiotic during the initial 24 hours when they are soaked in phosphate buffer solution (PBS). Thereafter, a slower drug release is produced, supplying minimum inhibitory concentration until the end of the experiment (30 days). Studies of growth inhibition ofStaphylococcus aureusandPseudomonas aeruginosain culture indicated that gentamicin released after 30 days fromα-TCP/HAP biphasic cement retained antibacterial activity.

scholarly journals Phase transformation of calcium phosphates in the presence of glutamic acid

2011 ◽  
Vol 89 (7) ◽  
pp. 885-891 ◽  
Author(s):  
Tim W. T. Tsai ◽  
Wei-Ya Chen ◽  
Yao-Hung Tseng ◽  
Jerry C. C. Chan
Keyword(s):  
Phase Transformation ◽  
Calcium Phosphate ◽  
Glutamic Acid ◽  
Crystal Surface ◽  
Calcium Phosphates ◽  
Water Layer ◽  
Octacalcium Phosphate ◽  
Growth Direction ◽  
Transformation Kinetics ◽  
Transformation Pathway

This work describes a phase-transformation pathway of calcium phosphate in the presence of glutamic acid. The route follows the order starting from amorphous calcium phosphate and brushite, then octacalcium phosphate (OCP), and finally hydroxyapatite (HAp). The preferred growth direction of the intermediate OCP and the final HAp phases lies along the c axis. On the basis of our scanning electron microscopy, X-ray powder diffraction, and 31P solid-state NMR data, we suggest that the transformation is via the dissolution–reprecipitation process, which is facilitated in the presence of glutamic acid. The effect on the transformation kinetics is rationalized by the disruption of the water layer bound on the crystal surface.

Effect of pH Values on Conversion of Calcite Crystals into Calcium Phosphate Phases in Buffer Solutions

2007 ◽  
Vol 353-358 ◽  
pp. 2183-2186 ◽  
Author(s):  
Ya Ping Guo ◽  
Bao Qiang Li ◽  
Yu Zhou ◽  
De Chang Jia
Keyword(s):  
Calcium Phosphate ◽  
Ph Value ◽  
Octacalcium Phosphate ◽  
Precipitation Reaction ◽  
X Ray Diffraction ◽  
Buffer Solution ◽  
Effect Of Ph ◽  
X Ray ◽  
Buffer Solutions ◽  
Ph Values

Calcium phosphate phases with laminar-plate structure were converted from calcite powders after soaking in phosphate buffer solutions of pH’s 6.0-8.0 at 37 °C for 9 days. The effect of pH values on the conversion of calcite crystals was investigated by X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy. If the pH value of a buffer solution is kept at 6.0, calcite powders are converted mainly to dicalcium phosphate dehydrate (DCPD) or octacalcium phosphate (OCP). If the pH value is kept at 6.4 or 7.0, calcite powders are converted mainly to OCP. Hydroxyapatite (HAP) with poorly crystalline can be obtained from calcite powders both by treatment of a basic buffer solution, and by treatment of an acid buffer solution without regulating its pH value during the reaction. The conversion mechanism of calcite crystals is a dissolution-precipitation reaction.

Effects of citrate and NaCl on size, morphology, crystallinity and microstructure of calcium phosphates obtained from aqueous solutions at acidic or near-neutral pH

2012 ◽  
Vol 79 (2) ◽  
pp. 238-248 ◽  
Author(s):  
Omar Mekmene ◽  
Thierry Rouillon ◽  
Sophie Quillard ◽  
Paul Pilet ◽  
Jean-Michel Bouler ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Octacalcium Phosphate ◽  
Inhibitory Effect ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Phosphate Dihydrate ◽  
Constant Ph ◽  
Starting Solutions ◽  
Calcium Phosphate Precipitation

Precipitation of calcium phosphates occurs in dairy products and depending on pH and ionic environment, several salts with different crystallinity can form. The present study aimed to investigate the effects of NaCl and citrate on the characteristics of precipitates obtained from model solutions of calcium phosphate at pH 6·70 maintained constant or left to drift. The ion speciation calculations showed that all the starting solutions were supersaturated with respect to dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP) and hydroxyapatite (HAP) in the order HAP>OCP>DCPD. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses of the precipitates showed that DCPD was formed at drifting pH (acidic final pH) whereas poor crystallised calcium deficient apatite was mainly formed at constant pH (6·70). Laser light scattering measurements and electron microscopy observations showed that citrate had a pronounced inhibitory effect on the crystallisation of calcium phosphates both at drifting and constant pH. This resulted in the decrease of the particle sizes and the modification of the morphology and the microstructure of the precipitates. The inhibitory effect of citrate mainly acted by the adsorption of the citrate molecules onto the surfaces of newly formed nuclei of calcium phosphate, thereby changing the morphology of the growing particles. These findings are relevant for the understanding of calcium phosphate precipitation from dairy byproducts that contain large amounts of NaCl and citrate.

Screening of Electrolyte Complexes Formed Between Dextran Sulfate and Amine Structures of Small-Molecule Drugs

2021 ◽  
Vol 21 (7) ◽  
pp. 3679-3682
Author(s):  
Seung Ah Choi ◽  
Eun Ji Park ◽  
Young Hun Kim ◽  
Jun-Pil Jee ◽  
Sung-Tae Kim ◽  
...  
Keyword(s):  
Small Molecule ◽  
Electrostatic Interactions ◽  
Dextran Sulfate ◽  
Drug Carrier ◽  
Acetate Buffer Solution ◽  
Carrier System ◽  
Buffer Solution ◽  
Small Molecule Drugs ◽  
Colloidal Drug Carrier ◽  
Drug Carrier System

Formation of an electrolyte complex using the electrostatic interactions between a polyanionic polymer and a cationic drug is a simple and efficient method of preparing a colloidal drug carrier system. Dextran sulfate, with a negatively charged sulfate group, was reacted in an acetate buffer solution of pH 3 with positively charged 1° amine, 2° amine, 3° amine, piperazine, and piperidine structures from 24 small-molecule drugs. The electrolyte complex was formed from 15 drugs, 63% of those tested. The tendency to form the electrolyte complex was in the order of piperazine and piperidine >3° amine >>2° amine. The drugs with the 1° amine structure failed to form an electrolyte complex. The mean particle sizes were in the range of 50-740 nm, and most of them showed a submicron colloidal dispersion of <400 nm. Regarding drug encapsulation efficiency (%), 11 drugs with piperazine, piperidine, and 3° amine structures showed 60–98% efficiency, which was fairly high. The results suggest that directly forming the electrolyte complex with dextran sulfate yields promising structural attributes as a submicron colloidal drug carrier system.

Preparation and Characterization of Chitosan-Gelatin Films with Na2SO4 Cross-Linked for Controlled-Release of Nitrofurantoin

2017 ◽  
Vol 757 ◽  
pp. 78-82 ◽  
Author(s):  
Weenawan Somphon ◽  
Siriporn Samnaree
Keyword(s):  
Controlled Release ◽  
Water Absorption ◽  
Drug Carrier ◽  
Phosphate Buffer Solution ◽  
Absorption Capacity ◽  
Antibacterial Drug ◽  
Buffer Solution ◽  
Scanning Calorimetry ◽  
Solution Ph ◽  
Nausea And Emesis

This work prepared and characterized of chitosan (Cs)-gelatin (Gel) films for the controlled release of the nitrofurantoin (NF) antibacterial drug. The side effects of NF are nausea and emesis due to its high absorption rate immediately after oral administration. The use of Cs-Gel films enables economic production of the drug carrier system. Cs-Gel films were prepared by mixing Cs with Gel at different ratios and were cross-linked with Na2SO4 with different concentrations. NF was loaded into the films by soaking of drug solution. Films were characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and evaluated for thickness, water absorption capacity, swelling behaviour and invitro NF drug release in phosphate buffer solution pH 5.8 and pH 7.4. The results indicated that additional amount of gelatin and sulfate ion cross-linked to the films increased the swelling, water absorption ability and also improved NF release.

Electrochemical Hydroxyapatite Coatings on Nitinol Stents for the Reduction of Metal Ions Elution

2014 ◽  
Vol 1626 ◽  
Author(s):  
Daisuke Kondo ◽  
Tomohiko Yoshioka ◽  
Toshiyuki Ikoma ◽  
Kensuke Takamatsu ◽  
Kunihiro Ohta ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Metal Ions ◽  
Calcium Phosphates ◽  
Toxic Metal ◽  
Octacalcium Phosphate ◽  
Electrolytic Deposition ◽  
Nickel Ions ◽  
Nitinol Stent ◽  
Hydroxyapatite Coatings ◽  
Nitinol Stents

ABSTRACTNitinol was coated with biocompatible calcium phosphate materials by pulsed electrolytic deposition (ELD) to reduce toxic metal-ions elution. The pulse ELD for the stents was carried out with changing the current off-periods (toff) of the pulse wave. The pulse ELD suppressed the generation of H2 gas due to the electrolysis of water on a calcium phosphate layer and improved the adhesiveness of the coating layer on nitinol compared with a conventional DC-ELD. The coating layers were identified to be octacalcium phosphate (OCP) at lower toff, while they were transformed to dicalcium phosphate anhydraous (DCPA) with an increase of toff. The layers of OCP or DCPA on the nitinol surface were subjected to a NaOH treatment at 60°C for 3days to transform them into hydroxyapatite (HAp). From results of a metal-ions elution test, the deposited calcium phosphates suppressed nickel ions elution at one quarter compared with the bare nitinol stent. These results indicate that the pulse ELD of biocompatible calcium phosphate materials on the nitinol stent was one of the best techniques to create firmly attached coating on it and reduce toxic nickel ions elution.

scholarly journals Study of the dissolution kinetics of drugs in solid dosage form with lisinopril and atorvastatin and intestinal permeability to assess their equivalence in vitro

Pharmacia ◽  
2022 ◽  
Vol 69 (1) ◽  
pp. 61-67
Author(s):  
Nataliia Shulyak ◽  
Kateryna Liushuk ◽  
Oksana Semeniuk ◽  
Nadiya Yarema ◽  
Tetyana Uglyar ◽  
...  
Keyword(s):  
Intestinal Permeability ◽  
Dosage Form ◽  
Phosphate Buffer Solution ◽  
Dissolution Kinetics ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Solid Dosage Form ◽  
Solid Dosage ◽  
Kinetics Of

Atorvastatin and lisinopril are a successful combination for the treatment of patients with chronic heart failure and hypertension. Study of the dissolution kinetics of drugs in solid dosage form with lisinopril and atorvastatin and intestinal permeability to assess their equivalence in vitro were described. In medium with hydrochloric acid pH 1.2, in the medium of acetate buffer solution with a pH of 4.5 and in the medium phosphate buffer solution with a pH of 6.8 for 15 min more than 85% of the active substance passes into solution, hence the dissolution profiles these drugs in these environments are similar, and the drugs in them are “very quickly soluble”. Among the in vitro models that make it possible to assess the degree of absorption of API, the most widely used culture of adenocarcinoma cells of the colon – Caco-2. The development of the analytical methodology and its validation is the final stage of both the dissolution study and the Caco-2 test, as well as the biowaver procedure. It plays the most important role in the reliability of the results for all the above procedures and tests. To study permeability, method LC-MS/MS was developed. According to the obtained results, atorvastatin and lisinopril showed low permeability. The values ​​of recovery of transport of test and control substances through the monolayer of cells of the Caco-2 line indicate that the results of the experiment can be considered reliable. The equivalence of the drugs “Lisinopril”, tablets of 10 mg and “Atorvastatin”, tablets of 10 mg, belongs to class III BCS proven by in vitro studies.

scholarly journals Release Profiles of Dyes and Proteins from Calcium Phosphate Microspheres with Different Crystalline Phases

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 291-301
Author(s):  
Toshiki Miyazaki ◽  
Koudai Masuda ◽  
Kazuki Sakamoto
Keyword(s):  
Calcium Phosphate ◽  
Anticancer Agents ◽  
Bone Repair ◽  
Calcium Phosphates ◽  
Molecular Size ◽  
Octacalcium Phosphate ◽  
Release Behavior ◽  
Crystalline Phases ◽  
Adsorption And Release ◽  
Ph Decrease

Calcium phosphate is attracting attention as a bone repair material and a controlled-release carrier of various drugs such as bone disease therapeutic agents and anticancer agents. Compared with some bioabsorbable polymers, calcium phosphates have the advantage of preventing a pH decrease in the surrounding body fluid. However, there are few studies comparing the effect of supporting substances with different physicochemical properties on the production of calcium phosphate microspheres with different crystalline phases. In this study, we investigated conditions for obtaining low crystallinity apatite and octacalcium phosphate (OCP) microspheres from calcium carbonate microspheres with different crystalline structures using a simple phosphoric acid treatment. Furthermore, we investigated the adsorption and release behavior of different dyes and proteins from the apatite and OCP microspheres. Overall, the factors governing the adsorption and release behavior are different depending on the molecular size and surface charge of the dye and protein adsorbates.

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