Use of antibiotic-impregnated bone grafts in a rabbit osteomyelitis model.

BACKGROUND: Both osteomyelitis and prosthetic joint infection can be treated surgically with the use of antibiotic loaded bone grafts, as part of local antimicrobial therapy. OBJECTIVE: The purpose of the study was to evaluate and to report on a novel, biodegradable, long-acting (4-6 weeks) antibiotic-impregnated bone graft (AIBG). A novel drug delivery system, containing vancomycin, was utilized in a rabbit osteomyelitis model in order to evaluate the antimicrobial efficacy of the antibiotic bone graft. METHODS: Forty adult New Zealand rabbits were used. The animals were randomized into three Groups: healthy animals without osteomyelitis, where AIBG was used to fill a defect (Group I); osteomyelitis caused with a methicillin-resistant S.aureus strain (MRSA) treated with AIBG (Group II); osteomyelitis caused with MRSA and treated with bone grafts without local antibiotics (Group III). At six weeks post-operation, the animals were sacrificed and histological, laboratory and radiologic evaluations were performed. RESULTS: Of the 24 operated rabbits, osteomyelitis was confirmed in 18 animals. In groups with osteomyelitis, only minor radiological changes were observed on day 21 post-op. Radiographs taken on day 42 post-op showed radiological signs of chronic osteomyelitis in Group III, whereas in Group II, bone healing was observed. Bacterial cultures taken on day 42 post-op revealed the original MRSA strain in Group III, whereas no bacteria were detected in Group II. Histological examinations showed the presence of macrophage cells which slowly break down the DDS matrix. The presence of DDS did not inhibit re-ossification. CONCLUSIONS: The drug delivery system was effective against MRSA-induced osteomyelitis without negative effect on osteointegration. This biodegradable technology has the potential to be a powerful tool in fighting bone infections.

[Development of new magistral method for the preparation of artificial tears]. / Korszeru tartósítási módszer fejlesztése magisztrálisan eloállítható mukönnyhöz.

Nowadays, large part of the population in Hungary is affected by the dry eye disease or symptom. Most of these magistral pharmaceuticals (FoNo VI) compared to the industrial products have disadvantages. They are not compatible with contact lenses, because of the preservatives and after opening they can be used only for seven days. In our experiments we used sodium-perborate as preservative, which could be a solution for the problems mentioned above. Our results indicate that the sodium-perborate sterilized the solution and resists against microbiological contamination. Its preservative effect maintained for more than four weeks. Our further purpose is to develop a new pharmacy drug preparation method to find an effective solution for the microbiological stability-related problems of artificial tears.

In vitro efficiency of vancomycin containing experimental drug delivery systems.

Biofilm-forming Staphylococcus epidermidis strains are common cause of the periprosthetic infection. The treatment of the periprosthetic infection is very problematic, so the prevention of these infections by an antibiotic containing prothesis could be an option for prevention.The purpose of the present study was to examine the in vitro effects of drug delivery systems (DDSs), namely Wax 1 and Wax 2 with different vancomycin content: 0.5, 1, 2 and 4 mg. In order to control the antibacterial activity of DDSs killing curve study was performed and in order to determine the antibiotic release and the antibiotic peak concentration from the DDSs biological assay was carried out.The time kill curve studies showed, that both DDSs with all vancomycin concentration decreased significantly the bacterial counts, however, Wax 2 with 4 mg vancomycin significantly decreased the bacterial count than all the other groups.The vancomycin release was the best with the highest peak concentration from DDSs with 4 mg vancomycin contain; it was significantly better than in the other groups, however, no significant difference was observed between Wax 1 and Wax 2 in this respect.These findings suggest that Wax 2 with 4 mg vancomycin content could be a potential agent for clinical use.

[Importance of the HLB-value in drug technology]. / A HLB-érték jelentosége a gyógyszertechnológiában.

Surface active agents can be classified 60 years ago with the introduction of the HLB system. The characterization of emulgents allowed their common use in the practice. The objective of the review is to summarize the research in the field of surface active agents and HLB-value. The basic principles and relationships related to HLB are detailed such as the predicting and experimental methods for the determination, as well as the achievements of development and applications of surface active agents.

[Gastrointestinal manifestation of Recklinghausen's disease]. / A Recklinghausen-kór enterális manifesztációja.

In a 52-year-old women suffering in Recklinghausen's disease, operated for acute abdomen, subserous neurinomas and neurofibroma were found on the jejunum and in the mesentery. Gastrointestinal tumors (neurofibroma, GIST, carcinoid etc.) should be considered in patients with Recklinghausen's disease and gastrointestinal symptoms.

[Designing antibiotic-containing carrier systems used in bone surgery]. / Csontmutéteknél alkalmazható antibiotikum-tartalmú hordozórendszerek tervezése.

The controlled release of antibiotics from bone can significantly reduce the prevalence of septic complication of revision operations. Consequently, the patients could avoid further operations and the hospitals could save the cost of repeated operations, which has economic notability too. The conditions of the correct antibiotic therapy are the right indication, the use of the most appropriate antibiotic, the right dose and the adequate duration of the therapy. The spread of antibiotic resistance is particularly important in the case of long residence time in a hospital. In revision surgery, periprothetic infections are principally caused by Staphylococcus aureus and Staphylococcus epidermidis, but in most cases it is needed to reckon with multiresistance strains. In such cases, patients take antibiotics for weeks before the surgery to heal the inflammation, in order to remove the infected prosthesis in time and implant the new one.

Gels and liposomes in optimized ocular drug delivery: studies on ciprofloxacin formulations.

Ciprofloxacin (CPFX) containing therapeutic systems were developed using gel- and liposome-based formulations to minimize tear-driven dilution in the conjunctival sac, a long-pursued objective in ophthalmology. Physicochemical properties (pH, osmolarity, viscosity, expansivity, membrane fluidity and in vitro CPFX release rate) of the preparations were studied by the appropriate methods. For gel preparation, the bio-adhesive poly(vinyl alcohol) and polymethacrylic acid derivatives were applied in various concentrations. In our liposome-supported carrier systems, multilamellar vesicles from lecithin and alpha-L-dipalmithoyl-phosphatidylcholine provided the encapsulating agent. Electron paramagnetic resonance (EPR) spectroscopy was applied to study the molecular interactions in the ophthalmic formulations. The polymer hydrogels used in our preparations ensured a steady and prolonged active ingredient release. In addition, encapsulation of the CPFX into liposomes prolonged the in vitro release of the antibacterial agent depending on the lipid composition of the vesicles.