The Open Orthopaedics Journal




ISSN: 1874-3250 ― Volume 13, 2019

In Vitro Elution Characteristics of Gentamicin and Vancomycin from Synthetic Bone Graft Substitutes



Gerrit Steffen Maier*, 1, Klaus Edgar Roth1, Stefan Andereya2, Klaus Birnbaum3, Christopher Niedhart4, Markus Lühmann5, Jörg Ohnsorge5, Uwe Maus6
1 Department of Orthopedic Surgery, Johannes-Guttenberg-University, Langenbeckstrasse 1, D-55131 Mainz, Germany
2 Orthopädische Gemeinschaftspraxis, Adalbertsteinweg 12, D-52070 Aachen, Germany
3 Orthopaedic Clinic Hennef, Adenauerplatz 1, D-53773 Hennef, Germany
4 Orthopädische Gemeinschaftspraxis, Liecker Str. 23, D-52525 Heinsberg, Germany
5 Orthopedic Center Oldenburger Münsterland, St. Antonius-Stift Emstek, Antoniusstr. 28, D-49685 Emstek, Germany
6 Department of Orthopedics and Special Orthopaedic Surgery, University Hospital for Orthopedic Surgery and Traumatology, Pius-Hospital, Georgstraße 12, D-26121 Oldenburg, Germany

Abstract

Objects:

Beta tricalciumphosphate pellets loaded with individualized antibiotics may represent novel options in the treatment of osteomyelitis and infectious bone disease. Here, the in vitro antibiotic elution of vancomycin and gentamicin from the synthetic bone graft substitutes Cerasorb® and Cerasorb M® was tested.

Methods:

Antibiotic elution and concentration of gentamcin and vancomycin were measured using photometrically-based measurement and homogeneous particle-enhanced turbidimetric inhibition immunoassays (PETINIA).

Results:

Initially both materials showed a high release of the loaded antibiotics, with Cerasorb M® showing lower release levels for gentamicin and vancomycin than Cerasorb®. Gentamicin concentrations of Cerasorb M granules and Cerasorb were below the minimum detectiontreshold until day four and six of the experiment respectively. The vancomycin release-level followed a similar pattern, although the vancomycin concentration eluted by Cerasorb M® granules stayed above the detection threshold during the experimental time.

Conclusions:

Cerasorb® and Cersorb M® may represent a new treatment option in osteomyelitis and infectious bone disease.

Keywords: Cerasorb®, Cerasorb M®, Osteomyelitis, beta tricalciumphosphate.


Article Information


Identifiers and Pagination:

Year: 2013
Volume: 7
First Page: 624
Last Page: 629
Publisher Id: TOORTHJ-7-624
DOI: 10.2174/1874325001307010624

Article History:

Received Date: 24/7/2013
Revision Received Date: 15/10/2013
Acceptance Date: 21/10/2013
Electronic publication date: 3 /11/2013
Collection year: 2013

Article Metrics:

CrossRef Citations:
0

Total Statistics:

Full-Text HTML Views: 1519
Abstract HTML Views: 1832
PDF Downloads: 312
Total Views/Downloads: 3663

Unique Statistics:

Full-Text HTML Views: 855
Abstract HTML Views: 738
PDF Downloads: 182
Total Views/Downloads: 1775
Geographical View

© Maier et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.


* Address correspondence to this author at the Department of Orthopedic Surgery, Johannes-Guttenberg-University, Langenbeckstrasse 1, D-55131 Mainz, Germany; Tel: 0049-6131-177302; Fax: 0040-6131-173416; E-mail: gerrit.s.maier@gmx.de





1. INTRODUCTION

The treatment of osteomyelitis remains a challenging problem for orthopaedic surgeons. Reaching a chronic state of osteomyelitis, the local vascularity is compromised. Therefore obtaining an effective local antibiotic concentration is hardly gained through oral or parental administration. Based on this knowledge, the local application of antibiotics, besides surgical debridement, represents a viable alternative treatment to handle osteomyelitis by reaching higher local antibiotic concentrations and minimizing systemic side effects [1Harle A, Ritzerfeld J. The release of gentamycin into the wound secretions from polymethylmethacrylate beads.A study with reference to the animal experiment. Arch Orthop Trauma Surg 1979; 95(1-2): 65-70.].

Since the introduction of antibiotic-impregnated composite and chains, the local application of antibiotics is a common and widely used procedure in the fields of trauma and orthopaedic surgery [2Klemm K. Gentamicin-PMMA-beads in treating bone and soft tissue infections (author's transl). Zentralbl Chir 1979; 104(14): 934-42., 3Buchholz HW, Engelbrecht H. [Depot effects of various antibiotics mixed with Palacos resins]. Chirurg 1970; 41(11): 511-.].

The main disadvantages in the utilisation of antibiotic-impregnated chains are the necessity of a second surgery to remove the material, as well as not being able to provide individualized chemotherapy in terms of local administration of different antibiotics.

Today there are several bone-graft substitutes available, which can be used as a controlled release delivery system for antibiotics. E.g. the usage of calcium sulfate as a bone graft substitute for bone lesions is known for a long time, with proven efficiency in experimental and clinical trials [4Alexander DI, Manson NA, Mitchell MJ. Efficacy of calcium sulfate plus decompression bone in lumbar and lumbosacral spinal fusion preliminary results in 40 patients. Can J Surg 2001; 44(4): 262-6.-7Mirzayan R, Panossian V, Avedian R, Forrester DM, Menendez LR. The use of calcium sulfate in the treatment of benign bone lesions.A preliminary report. J Bone Joint Surg Am 2001; 83-A(3): 355-8.]. Adversely several trials showed a transient cytotoxic effect of calcium sulphate, resulting in inflammatory reactions [8Coetzee AS. Regeneration of bone in the presence of calcium sulfate. Arch Otolaryngol 1980; 106(7): 405-9.-10Robinson D, Alk D, Sandbank J, Farber R, Halperin N. Inflammatory reactions associated with a calcium sulfate bone substitute. Ann Transplant 1999; 4(3-4): 91-7.].

Nevertheless in several trials calcium sulphate was used as an antibiotic-carrier material and has proven its efficiency as well as its security as a carrier substance [11Dacquet V, Varlet A, Tandogan RN. Antibiotic-impregnated plaster of Paris beads.Trials with teicoplanin. Clin Orthop Relat Res 1992; 282: 241-9., 12McKee MD, Wild LM, Schmeimitsch EH, Waddell JP. The use of an antibiotic-impregnated osteoconductive bioabsorbable bone substitute in the treatment of infected long bone defects: early results of a prospective trial. J Orthop Trauma 2002; 16(9): 622-7.].

The major drawback in earlier studies of calcium sulphate as an antibiotic-carrier material was the addition of the appropriate antibiotic to the calcium sulphate before hardening, creating possible risks of impairing the antibiotic activity due to hardening or sterilization procedures [11Dacquet V, Varlet A, Tandogan RN. Antibiotic-impregnated plaster of Paris beads.Trials with teicoplanin. Clin Orthop Relat Res 1992; 282: 241-9.].

Today there is a formulation of the material solving this problem by loading the antibiotic after sterilization, directly before application [13Gitelis S, Brebach GT. The treatment of chronic osteomyelitis with a biodegradable antibiotic-impregnated implant. J Orthop Surg (Hong Kong) 2002; 10(1): 53-60.].

Due to the cytotoxic effect of pure calcium sulphate and the probable loss of antibiotic efficiency during hardening, several combinations of calcium sulphate with different materials were developed, e.g. the combination of calcium sulphate and nanochrystalline hydroxyapatite. This combination is available in different moulds, which can be loaded with antibiotics after sterilization or hardening. Over a period of 10 days the composite material of calcium sulphate and hydroxyapatite showed a nearly complete release of the loaded antibiotics. Within these 10 days of trial the composite material revealed high initial antibiotic release with subsequent decline. The different release of antibiotics between the combination of a calcium sulphate/hydroxyapatite mixture and pure calcium sulphate was compared in several studies. Such studies found a higher early release (during the first 5 days) for the calcium sulphate/hydroxyapatite mixture. After 5 days of trial pure calcium sulphate showed a higher antibiotic release [14Rauschmann MA, Wichelhaus TA, Stirnal V. Nanocrystalline hydroxyapatite and calcium sulphate as biodegradable composite carrier material for local delivery of antibiotics in bone infections. Biomaterials 2005; 26: 2677-84.].

The same studies also showed an excellent resorption rate, biocompatibility and antibiotic release for the calcium sulphate/hydroxyapatite composite material.

Several other materials were shown to display similarly high levels of biocompatibility, resorption rate and osseointegration. Widely available are calciumphosphates, mainly hydoxyapatite and tricalciumphosphate. Both materials are reasonable alternatives for the current gold standard in the treatment of bone lesions, the autogenic cancelous bone repair [15Dorozhkin SV, Epple M. Biological and medical significance of calcium phosphates. Angew Chem Int Ed Engl 2002; 41(17): 3130-46., 16Ransford AO, Morley T, Edgar MA. Synthetic porous ceramic compared with autograft in scoliosis surgery.A prospective randomized study of 341 patients. J Bone Joint Surg Br 1998; 80(1): 13-8.].

The aim of this study was to evaluate the applicability of Cerasorb® (Curasan AG), a beta tricalciumphosphate ceramic, as a carrier substance for antibiotics by measuring in vitro the release kinetics of gentamicin and vancomycin [17Szabo G, Huys L, Coullthard P. A prospective multicenter randomized clinical trial of autogenous bone versus beta-tricalcium phosphate graft alone for bilateral sinus elevation: histologic and histomorphometric evaluation. Int J Oral Maxillofac Implants 2005; 20(3): 371-81., 18Maus U. Klinische Erfahrungen mit dem Knochenersatzstoff Cerasorb. Orthop dische Praxis 2007; 43: 258-61.].

Former studies showed the principal usage of beta- tricalciumphosphate as a carrier substance for proteins like BMP-2 [19Kim CS, Kim JI, Kim J, et al. Ectopic bone formation associated with recombinant human bone morphogenetic proteins-2 using absorbable collagen sponge and beta tricalcium phosphate as carriers. Biomaterials 2005; 26(15): 2501-7.].

2. MATERIALS AND METHODS

2.1. Antibiotic Carrier

We used Cerasorb® and Cerasorb M® as it was supplied to us by the manufacturer Curasan AG, Germany. Cerasorb® ortho has an open interconnecting microporosity of 35 % and is available in a round shape. Cerasorb M® features an interconnecting, open multi porosity with micro, meso and macro pores (5 µm - 500 µm) and a total porosity of approx. 65%. The granules are polygonal, i.e. irregularly shaped, and facilitate canting and interlocking in the defect cavity. Micro movements are largely prevented.

Both materials have a phase purity of more than 99% ß-tricalciumphosphate. For this study we had 10 pieces of Cerasorb® and Cerasorb M® at our disposal. Each of which measured 1x1x1 cm. One granule of each group was tested on the absorption of the antibiotics vancomycin and gentamicin. The remaining granules were tested on the release kinetic either of vancomycin or gentamicin, 4 granules per each antibiotic.

2.2. Antibiotic Uptake and Release

Both bone graft substitutes were loaded with antibiotics via a soaking process. 5 pellets of Cerasorb® and Cerasorb M® were soaked for 1 minute in a gentamicin (Gentamicin-ratiopharm 80 SF, Ratiopharm GmbH, Ulm) solution (40 mg/ml). The pellets were kept at room temperature and completely covert by the solution during the soaking process.

The vancomycin solution was produced by injecting 10 ml water for injection into the dry matter vancomycin (Vancomycin CP, Hikma Pharma GmbH, Gräfeling), thus creating a solution of 50 mg/ml. 5 pellets of Cerasorb® and Cerasorb M® were soaked for 1 minute in the vancomycin solution. As above the pellets were completely covered by the solution and kept at room temperature during the soaking process.

To measure the antibiotic uptake one pellet of Cerasorb® and Cerasorb M® loaded with either one of the antibiotics was pestled. Subsequently the material was mixed with 4 ml PBS and incubated at 37° for 24 hours. Supernatants were removed and stored at -80°. The antibiotic content was measured in the supernatant.

In order to determinine the release kinetics each of the two antibiotics was soaked into 4 pellets of Cerasorb® and 4 pellets of Cerasorb M®. We examined the elution in 4 ml phosphate-buffered saline (PBS) at pH 7,4 and 37°. Every 24 hours the supernatant was taken from the solution and 1 ml was preserved at -80°. The remaining pellets were cleaned with PBS and again covered with 4 ml of fresh PBS. This procedure was continued for 10 days.

The taken samples were preserved at -80° and defrosted immediately before being assayed with either MULTIGENT Gentamicin or Vancomycin assay (Abbott Laboratories Inc., USA), both homogeneous particle-enhanced turbidimetric inhibition immunoassays (PETINIA). Both assays were based on competition between drug in the sample and drug coated onto a microparticle for antibody binding sites of the gentamicin or vancomycin antibody reagent. The genta-micin- or vancomycin-coated microparticle reagent was rapidly agglutinated in the presence of the anti-genta-micin/vancomycin antibody reagent and in the absence of any competing drug in the sample.

The rate of absorbance change was measured photo-metrically and was directly proportional to the rate of agglutination of the particles. When a sample containing gentamicin/vancomycin was added, the agglutination reaction was partially inhibited, slowing down the rate of absorbance change. A concentration-dependent classic agglutination inhibition curve can be obtained with maximum rate of agglutination at the lowest gentamicin/vancomycin concentration, and the lowest agglutination rate at the highest gentamicin/vancomycin concentration.

The antibiotic concentration of the eluates was determined by an automatic antibiotic concentration analysing system (Architect 4000, Abbott Laboratories Inc., USA).

3. RESULTS

The loading of the granules showed no technical difficulties and does not affect the macroscopic or mechanical features of the granules after being loaded.

Antibiotic uptake of gentamicin was 406,38 μg/ml for Cerasorb ® and 145,2 μg /ml for Cerasorb M®. The uptake of vancomycin was 1552,4 μg /ml for Cerasorb®, Cerasorb M ® granules had an uptake of 149 μg/ml.

Release kinetics of both granule types were measured as described by Rauschmann et al. [14Rauschmann MA, Wichelhaus TA, Stirnal V. Nanocrystalline hydroxyapatite and calcium sulphate as biodegradable composite carrier material for local delivery of antibiotics in bone infections. Biomaterials 2005; 26: 2677-84.]. Initially both materials showed a high release of the loaded antibiotics, Cerasorb M® showing a lower initial release level for gentamicin and vancomycin than Cerasorb®. At day 4 the gentamicin concentration of the Cerasorb M® granules was under the detection treshold, for Cerasorb® the gentamicin concentration was undetectable at day 6 (Fig. 1, Table 1).

Fig. (1)

Elution pharmacokinetics of Gentamicin from Cerasorb® and Cerasorb M®. Antibiotic release is expressed in μg /ml. Mean values were derived from a total of 4 different tests. Granules were loaded in a solution of 40 g/L antibiotics.



Table 1

Elution Pharmacokinetics and Standard Deviation of Gentamicin from Cerasorb® and Cerasorb M®. Antibiotic Release is Expressed in µg /ml. Mean Values were Derived from a Total of 4 Different Tests. Granules were Loaded in a Solution of 40 g/L Antibiotics




The vancomycin release-level followed a similar pattern, although the vancomycin concentration eluted by Cerasorb M® granules stayed above the detection threshold during the period of the experimental (Fig. 2, Table 2).

Fig. (2)

Elution pharmacokinetics of vancomycin from Cerasorb® and Cerasorb M®. Antibiotic release is expressed in μg /ml. Mean values were derived from a total of 4 different tests. Granules were loaded in a solution of 50 g/L antibiotic.



Table 2

Elution Pharmacokinetics and Standard Deviation of Vancomycin from Cerasorb® and Cerasorb M®. Antibiotic Release is Expressed in µg /ml. Mean Values were Derived from a Total of 4 Different Tests. Granules were Loaded in a Solution of 50 g/L Antibiotics




DISCUSSION

Osteomyelitis is a difficult infection to treat and to eradicate. It represents a challenge for orthopaedic surgeons worldwide. Multiple surgical debridements and long-term parental antibiotics are often required for effective therapy. Besides these techniques, the local administration of antibiotics plays a crucial role in a successful therapy.

The main goal for local antibiotic therapies is to deliver an effective antimicrobial at sufficiently high concentrations to the area of infection. It is usually performed in addition with the use of polymethylmetacrylate (PMMA) beads and bone cements. The disadvantages associated with the usage of PMMA beads include being determined to one antibiotic at a time and the necessity of a second surgery to remove the beads after the antibiotic elution [2Klemm K. Gentamicin-PMMA-beads in treating bone and soft tissue infections (author's transl). Zentralbl Chir 1979; 104(14): 934-42., 3Buchholz HW, Engelbrecht H. [Depot effects of various antibiotics mixed with Palacos resins]. Chirurg 1970; 41(11): 511-., 21Liu SJ, Ueng SW, Chan EC. In vitro elution of vancomycin from biodegradable beads. J Biomed Mater Res 1999; 48(5): 613-20.].

All these disadvantages made an intense search for possible alternatives necessary. An ideal antibiotic delivery system should provide an adequate antimicrobial concentration at the target site a constant release of antimicrobial over a prolonged period and be biodegradable to avoid the necessity of a second surgery [30Joosten U, Joist A, Gosheger G, Liljenqvist U, Brandt B, vonEiff C. Effectiveness of hydroxyapatite-vancomycin bone cement in the treatment of Staphylococcus aureus induced chronic osteomyelitis. Biomaterials 2005; 26(25): 5251-8.].

One possible alternative is calciumsulphate, which is, as several studies showed, an adequate local drug delivery system [11Dacquet V, Varlet A, Tandogan RN. Antibiotic-impregnated plaster of Paris beads.Trials with teicoplanin. Clin Orthop Relat Res 1992; 282: 241-9., 12McKee MD, Wild LM, Schmeimitsch EH, Waddell JP. The use of an antibiotic-impregnated osteoconductive bioabsorbable bone substitute in the treatment of infected long bone defects: early results of a prospective trial. J Orthop Trauma 2002; 16(9): 622-7.]. Admittedly during the first 60 days after implantation calciumsulphate causes inflammatory reactions in the circumjacent tissue [8Coetzee AS. Regeneration of bone in the presence of calcium sulfate. Arch Otolaryngol 1980; 106(7): 405-9.]. After day 60 the inflammation ceases in the affected bone, but not in the circumjacent soft tissue.

Lactic-acid polymer gained interest as antibiotic carrier material. These polymers are biodegradable, making a second surgery to remove the carrier material unnecessary. In vitro, as well as in vivo, lactic-acid polymers showed a high release kinetic of loaded antibiotics [22Benoit MA, Mousset B, Delloye C, Bouillet R, Gillard J. Antibiotic-loaded plaster of Paris implants coated with poly lactide-co-glycolide as a controlled release delivery system for the treatment of bone infections. Int Orthop 1997; 21(6): 403-8.-25Wie G, Kotoura Y, Oka M. A bioabsorbable delivery system for antibiotic treatment of osteomyelitis.The use of lactic acid oligomer as a carrier. J Bone Joint Surg Br 1991; 73(2): 246-52.]. A big drawback is its nonexistent osteoconductive property. Lactic-acid polymers are not commercially available. The addition of nanocrystalline hydroxyapatite to calciumsulphate enhanced the biocompatibility of calciumsulphate in a composite material. This combination showed a reduced inflammatory reaction in the adjacent soft tissue in comparison to pure calciumsulphate, as well as higher osteoconductive properties and provides a scaffold for new bone formation [26Sato S, Koshino T, Saito T. Osteogenic response of rabbit tibia to hydroxyapatite particle-Plaster of Paris mixture. Biomaterials 1998; 19(20): 1895-900.]. In vitro the calciumsulphate hydroxyapatite composite showed a high release rate of the loaded antibiotics, in particular during the first days of the trial this antibiotic delivery system showed local effective antibiotic concentrations above the minimal inhibiting concentration (MIC) of vancomycin and gentamicin susceptible pathogens [14Rauschmann MA, Wichelhaus TA, Stirnal V. Nanocrystalline hydroxyapatite and calcium sulphate as biodegradable composite carrier material for local delivery of antibiotics in bone infections. Biomaterials 2005; 26: 2677-84.]. The most relevant pathogen for bone infections is Staph. Aureus, showing an MIC90 (antibiotic concentration that inhibits growth of 90% Staph. Aureus strains) of 1 mg/L for both vancomycin and gentamicin in susceptible strains [14Rauschmann MA, Wichelhaus TA, Stirnal V. Nanocrystalline hydroxyapatite and calcium sulphate as biodegradable composite carrier material for local delivery of antibiotics in bone infections. Biomaterials 2005; 26: 2677-84., 23Kanellakopoulou K, Kolia M, Anastassiadis A. Lactic acid polymers as biodegradable carriers of fluoroquinolones an in vitro study. Antimicrob Agents Chemother 1999; 43(3): 714-6., 27Fluit AC, Jones ME, Schmitz FJ, Acar J, Gupta R, Verhoef J. Antimicrobial susceptibility and frequency of occurrence of clinical blood isolates in Europe from the SENTRY antimicrobial surveillance program, 1997 and 1998. Clin Infect Dis 2000; 30(3): 454-60.].

Calcium sulphate preloaded with Tobramycin (OsteoSet®T) in combination with surgical debridement showed promising results in the treatment of infected bone defects. However, an individualized chemotherapy in terms of local administration of different antibiotics is not provided [12McKee MD, Wild LM, Schmeimitsch EH, Waddell JP. The use of an antibiotic-impregnated osteoconductive bioabsorbable bone substitute in the treatment of infected long bone defects: early results of a prospective trial. J Orthop Trauma 2002; 16(9): 622-7.]. To avoid the emerging tobramycin resistance custom-made calciumsulphate pellets, individually loaded with the appropriate antibiotic, are commercially available. In clinical and experimental studies these pellets showed a high efficiency in treating osteomyelitis. However, antibiotic loading has to be done before hardening and sterilization, creating a potential risk of reducing antibiotic efficiency. Adding the antibiotic during the process of hardening may impair the antibiotic elution. Dacquet et al. showed that the elution of teicoplanin, which was added to the calcium sulphate powder before hardening, was only 1-5 μg during the first 10 days, too low for an effective osteomyelitis treatment [11Dacquet V, Varlet A, Tandogan RN. Antibiotic-impregnated plaster of Paris beads.Trials with teicoplanin. Clin Orthop Relat Res 1992; 282: 241-9.]. Furthermore, there is a potential deceleration in the surgical procedure due to the 12-14 minutes of hardening.

In the current study we tried to minimize possible risks of impairing antibiotic activity due to any hardening or sterilization processes. To prevent inactivation of antibiotics by hardening or sterilization we performed the loading of antibiotics after these procedures. The ready-for use pellets completely absorbed the antibiotic solution. By comparing Cerasorb® and Cerasorb® M with their different porosities, we proved that antibiotic uptake and release are influenced by different porosities of the bone graft pellets. The higher porosity of Cerasorb® M showed a lower release of both loaded antibiotics from the start. The antibiotic concentrations never reached the antibiotic concentrations eluted by Cerasorb®. This result is in accordance with several other studies [14Rauschmann MA, Wichelhaus TA, Stirnal V. Nanocrystalline hydroxyapatite and calcium sulphate as biodegradable composite carrier material for local delivery of antibiotics in bone infections. Biomaterials 2005; 26: 2677-84., 20Wichelhaus TA, Dingeldein E, Rauschmann M. Elution characteristics of vancomycin teicoplanin gentamicin and clindamycin from calcium sulphate beads. J Antimicrob Chemother 2001; 48(1): 117-9.]. Based on a minimal inhibition concentration (MIC) of 1 mg/L for both vancomycin and gentamicin, both materials achieved effective local antibiotic concentrations for Staph aureus within the first 4 and 5 days, respectively. After day 4 and 5, respectively, for both tested bone graft materials local antibiotic concentrations were less than the MIC and under the detection treshold. Rauschmann et al. reported similar results for the elution of vancomyin and gentamicin with nanocrystaline hydroxyapatite calcium sulphate as a carrier material. Local antibiotic concentrations for both antibiotics were initially high and stayed above the detection treshold for 3-4 days [14Rauschmann MA, Wichelhaus TA, Stirnal V. Nanocrystalline hydroxyapatite and calcium sulphate as biodegradable composite carrier material for local delivery of antibiotics in bone infections. Biomaterials 2005; 26: 2677-84.]. The present study showed concentrations of released gentamicin and vancomycin exceeding 100-1000-fold the MIC of susceptible Staph. aureus within the first day, at day 2 and 3 the MIC was exceeded 10-100-fold.

Prima facie these results seem to be comparable with the results reported by Rauschmann et al., however, the main difference is the method to measure the antibiotic concentration. Rauschmann et al. used a standard agar diffusion test with Bacillus subtilis ATCC 6633. In contrast, we used machine-aided diagnosis to evaluate the antibiotic elution of both used bone graft substitutes [14Rauschmann MA, Wichelhaus TA, Stirnal V. Nanocrystalline hydroxyapatite and calcium sulphate as biodegradable composite carrier material for local delivery of antibiotics in bone infections. Biomaterials 2005; 26: 2677-84.]. Wichelhaus et al. used the standard agar diffusion test as well in their evaluation of the release of 4 different antibiotics from calcium sulphate carrier beads and found antibiotic release to be above the MIC for a period of ten days [20Wichelhaus TA, Dingeldein E, Rauschmann M. Elution characteristics of vancomycin teicoplanin gentamicin and clindamycin from calcium sulphate beads. J Antimicrob Chemother 2001; 48(1): 117-9.].

Miclau et al. showed a high initial antibiotic release from autogenic bone graft and demineralized bone matrix during the first days of their study, whereas PMMA- and calcium sulphate carrier beads showed a prolonged release of the loaded antibiotics [29Miclau T, Dahners LE, Lindsey RW. In vitro pharmacokinetics of antibiotic release from locally implantable materials. J Orthop Res 1993; 11(5): 627-32.]. A major drawback of autogenic bone graft is the required removal of the bone graft resulting in a high risk for complications, as well as its limited disposability. Demineralized bone matrix is not rugged and due to its structure is limited in the way it acts as an osteoconductive scaffold.

In contrast calcium phosphate ceramics, like hydroxyapatite and tricalciumphoshate, are available in large quantities and show excellent osteoconductive features. Different studies have proven the qualification of hydroxyapatite as a local antibiotic delivery system [28Cornell CN, Tyndall D, Walter S, Lane JM, Brause BD. Treatment of experimental osteomyelitis with antibiotic-impregnated bone graft substitute. J Orthop Res 1993; 11(5): 619-26., 30Joosten U, Joist A, Gosheger G, Liljenqvist U, Brandt B, vonEiff C. Effectiveness of hydroxyapatite-vancomycin bone cement in the treatment of Staphylococcus aureus induced chronic osteomyelitis. Biomaterials 2005; 26(25): 5251-8.].

CONCLUSION

The tricalcium phosphate ceramics Cerasorb® and Cerasorb® M are well established as bone graft substitutes. In the current study we loaded both ceramics with vancomycin and gentamycin to create a local antibiotic delivery system. The pre-fabricated pellets were loaded after sterilization and hardening to prevent inactivation of antibiotics by these procedures. We showed a high initial antibiotic release with subsequent decline well above the MIC of Staph aureus for both materials within the first 4 and 5 days, respectively. The pre-fabricated pellets offer fast and technically easy loading with the selected antibiotic. Loading can be done according to antibiograms offering individualized antibiotic treatment options. Due to the osteoconductive and biodegradability properties of Cerasorb® and Cerasorb M® there is nor need for removal of the material as in the case with PMMA. Given the different technical features of both ceramics it enables practitioners to react to different clinical requirements, e.g. slower or faster resorption.

In conclusion Cerasorb® and Cersorb M® has potential as a new treatment option in osteomyelitis and infectious bone disease.

CONFLICT OF INTEREST

The authors confirm that this article content has no conflict of interest.

ACKNOWLEDGEMENTS

This work was supported in part by Curasan AG, Kleinostheim, Germany.

REFERENCES

[1] Harle A, Ritzerfeld J. The release of gentamycin into the wound secretions from polymethylmethacrylate beads.A study with reference to the animal experiment. Arch Orthop Trauma Surg 1979; 95(1-2): 65-70.
[2] Klemm K. Gentamicin-PMMA-beads in treating bone and soft tissue infections (author's transl). Zentralbl Chir 1979; 104(14): 934-42.
[3] Buchholz HW, Engelbrecht H. [Depot effects of various antibiotics mixed with Palacos resins]. Chirurg 1970; 41(11): 511-.
[4] Alexander DI, Manson NA, Mitchell MJ. Efficacy of calcium sulfate plus decompression bone in lumbar and lumbosacral spinal fusion preliminary results in 40 patients. Can J Surg 2001; 44(4): 262-6.
[5] Gitelis S, Piasecki P, Turner T, Haggard W, Charters J, Urban R. Use of a calcium sulfate-based bone graft substitute for benign bone lesions. Orthopedics 2001; 24(2): 162-6.
[6] Kelly CM, Wilkins RM, Gitelis S, Hartjen C, Watson JT, Kim PT. The use of a surgical grade calcium sulfate as a bone graft substitute results of a multicenter trial. Clin Orthop Relat Res 2001; (382): 42-50.
[7] Mirzayan R, Panossian V, Avedian R, Forrester DM, Menendez LR. The use of calcium sulfate in the treatment of benign bone lesions.A preliminary report. J Bone Joint Surg Am 2001; 83-A(3): 355-8.
[8] Coetzee AS. Regeneration of bone in the presence of calcium sulfate. Arch Otolaryngol 1980; 106(7): 405-9.
[9] Lee GH, Khoury JG, Bell JE, Buckwalter JA. Adverse reactions to OsteoSet bone graft substitute the incidence in a consecutive series. Iowa Orthop J 2002; 22: 35-8.
[10] Robinson D, Alk D, Sandbank J, Farber R, Halperin N. Inflammatory reactions associated with a calcium sulfate bone substitute. Ann Transplant 1999; 4(3-4): 91-7.
[11] Dacquet V, Varlet A, Tandogan RN. Antibiotic-impregnated plaster of Paris beads.Trials with teicoplanin. Clin Orthop Relat Res 1992; 282: 241-9.
[12] McKee MD, Wild LM, Schmeimitsch EH, Waddell JP. The use of an antibiotic-impregnated osteoconductive bioabsorbable bone substitute in the treatment of infected long bone defects: early results of a prospective trial. J Orthop Trauma 2002; 16(9): 622-7.
[13] Gitelis S, Brebach GT. The treatment of chronic osteomyelitis with a biodegradable antibiotic-impregnated implant. J Orthop Surg (Hong Kong) 2002; 10(1): 53-60.
[14] Rauschmann MA, Wichelhaus TA, Stirnal V. Nanocrystalline hydroxyapatite and calcium sulphate as biodegradable composite carrier material for local delivery of antibiotics in bone infections. Biomaterials 2005; 26: 2677-84.
[15] Dorozhkin SV, Epple M. Biological and medical significance of calcium phosphates. Angew Chem Int Ed Engl 2002; 41(17): 3130-46.
[16] Ransford AO, Morley T, Edgar MA. Synthetic porous ceramic compared with autograft in scoliosis surgery.A prospective randomized study of 341 patients. J Bone Joint Surg Br 1998; 80(1): 13-8.
[17] Szabo G, Huys L, Coullthard P. A prospective multicenter randomized clinical trial of autogenous bone versus beta-tricalcium phosphate graft alone for bilateral sinus elevation: histologic and histomorphometric evaluation. Int J Oral Maxillofac Implants 2005; 20(3): 371-81.
[18] Maus U. Klinische Erfahrungen mit dem Knochenersatzstoff Cerasorb. Orthop dische Praxis 2007; 43: 258-61.
[19] Kim CS, Kim JI, Kim J, et al. Ectopic bone formation associated with recombinant human bone morphogenetic proteins-2 using absorbable collagen sponge and beta tricalcium phosphate as carriers. Biomaterials 2005; 26(15): 2501-7.
[20] Wichelhaus TA, Dingeldein E, Rauschmann M. Elution characteristics of vancomycin teicoplanin gentamicin and clindamycin from calcium sulphate beads. J Antimicrob Chemother 2001; 48(1): 117-9.
[21] Liu SJ, Ueng SW, Chan EC. In vitro elution of vancomycin from biodegradable beads. J Biomed Mater Res 1999; 48(5): 613-20.
[22] Benoit MA, Mousset B, Delloye C, Bouillet R, Gillard J. Antibiotic-loaded plaster of Paris implants coated with poly lactide-co-glycolide as a controlled release delivery system for the treatment of bone infections. Int Orthop 1997; 21(6): 403-8.
[23] Kanellakopoulou K, Kolia M, Anastassiadis A. Lactic acid polymers as biodegradable carriers of fluoroquinolones an in vitro study. Antimicrob Agents Chemother 1999; 43(3): 714-6.
[24] Kanellakopoulou K, Galanakis N, Giamarellos-Bourboulis EJ. Treatment of experimental osteomyelitis caused by methicillin-resistant Staphylococcus aureus with a biodegradable system of lactic acid polymer releasing pefloxacin. J Antimicrob Chemother 2000; 46(2): 311-4.
[25] Wie G, Kotoura Y, Oka M. A bioabsorbable delivery system for antibiotic treatment of osteomyelitis.The use of lactic acid oligomer as a carrier. J Bone Joint Surg Br 1991; 73(2): 246-52.
[26] Sato S, Koshino T, Saito T. Osteogenic response of rabbit tibia to hydroxyapatite particle-Plaster of Paris mixture. Biomaterials 1998; 19(20): 1895-900.
[27] Fluit AC, Jones ME, Schmitz FJ, Acar J, Gupta R, Verhoef J. Antimicrobial susceptibility and frequency of occurrence of clinical blood isolates in Europe from the SENTRY antimicrobial surveillance program, 1997 and 1998. Clin Infect Dis 2000; 30(3): 454-60.
[28] Cornell CN, Tyndall D, Walter S, Lane JM, Brause BD. Treatment of experimental osteomyelitis with antibiotic-impregnated bone graft substitute. J Orthop Res 1993; 11(5): 619-26.
[29] Miclau T, Dahners LE, Lindsey RW. In vitro pharmacokinetics of antibiotic release from locally implantable materials. J Orthop Res 1993; 11(5): 627-32.
[30] Joosten U, Joist A, Gosheger G, Liljenqvist U, Brandt B, vonEiff C. Effectiveness of hydroxyapatite-vancomycin bone cement in the treatment of Staphylococcus aureus induced chronic osteomyelitis. Biomaterials 2005; 26(25): 5251-8.

Endorsements



"Open access will revolutionize 21st century knowledge work and accelerate the diffusion of ideas and evidence that support just in time learning and the evolution of thinking in a number of disciplines."


Daniel Pesut
(Indiana University School of Nursing, USA)

"It is important that students and researchers from all over the world can have easy access to relevant, high-standard and timely scientific information. This is exactly what Open Access Journals provide and this is the reason why I support this endeavor."


Jacques Descotes
(Centre Antipoison-Centre de Pharmacovigilance, France)

"Publishing research articles is the key for future scientific progress. Open Access publishing is therefore of utmost importance for wider dissemination of information, and will help serving the best interest of the scientific community."


Patrice Talaga
(UCB S.A., Belgium)

"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."


Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."


Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."


Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."


Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."


J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."


Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."


Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."


Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."


Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."


Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."


M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."


Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."


Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."


Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."


Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."


Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."


Jih Ru Hwu
(National Central University, Taiwan)


Browse Contents




Webmaster Contact: info@benthamopen.net
Copyright © 2019 Bentham Open