Development of Zoledronic Acid Containing Biomaterials for Enhanced Guided Bone Regeneration.

In recent years, biomaterial-based treatments, also called guided bone regeneration (GBR), which aim to establish a bone regeneration site and prevent the migration of gingival connective tissue and / or peripheral epithelium through the defective area during periodontal surgical procedures have come to the fore. In this report, we have developed a nanoparticle bearing thermosensitive in situ gel formulation of Pluronic F127 and poly(D,L-lactic acid) based membrane to reveal their utilization at GBR by in-vivo applications. In addition, the encouragement of the bone formation in defect area via inhibition of osteoclastic activity is intended by fabrication these biodegradable biomaterials at a lowered Zoledronic Acid (ZA) dose. Both of the developed materials remained stable under specified stability conditions (25 °C, 6 months) and provided the extended release profile of ZA. The in-vivo efficacy of nanoparticle bearing in situ gel formulation, membrane formulation and simultaneous application for guided bone regeneration was investigated in New Zealand female rabbits with a critical size defect of 0.5 × 0.5 cm in the tibia bone for eight weeks. Based on the histopathological findings, lamellar bone and primarily woven bone formations were observed after 8 weeks of post-implantation of both formulations, while fibrosis was detected only in the untreated group. Lamellar bone growth was remarkably achieved just four weeks after the simultaneous application of formulations. Consequently, the simultaneous application of ZA-membrane and ZA-nanoparticles loaded in-situ gel formulations offers enhanced and faster GBR therapy alternatives.

Guided bone regeneration by the development of alendronate sodium loaded in-situ gel and membrane formulations.

Biocompatible materials applied in guided bone regeneration are needed to prevent leakage caused by the invasion of peripheral epithelium. (2.1) The aim of this study is to develop a thermosensitive in situ gel system containing alendronate sodium loaded PLGA nanoparticles and alendronate sodium loaded membranes for guided bone regeneration. Thermosensitive Pluronic F127 gel system was preferred to prevent soft tissue migration to the defect site and prolong the residence time of the nanoparticles in this region. In situ gel system was combined with membrane formulation to enhance bone regenaration activity. Efficacy of combination system was investigated by implanting in 0.5 × 0.5 cm critical size defect in tibia of New Zealand female rabbits. According to the histopathological results, fibroblast formations were found at defect area after 6 weeks of post implantation. In contrast, treatment with the combination of in-situ gel containing nanoparticles with membrane provided woven bone formation with mature bone after 4 weeks of post implantation. As a results, the combination of in-situ gel formulation containing alendronate sodium-loaded nanoparticles with membrane formulation could be effectively applided for guided bone regeneration.

Antebrachial Angular Deformities Using Computer-Assisted Hexapod External Fixator Systems in Dogs.

OBJECTIVE: The aim of this study was to investigate the applicability of computer-assisted hexapod fixators in dogs and to consider the advantages and disadvantages during implementation. MATERIALS AND METHODS: This was a prospective study. The study material consisted of 11 deformed extremities of 6 dogs. The correction plans were defined according to multiple extremity radiographs of the dog and the clinical evaluation of deformities. All measurements were uploaded to Click2Correct software program. Latent, correction and consolidation periods of each dog were recorded. The hexapod external fixators were removed after completion of the correction. RESULTS: Data were adapted to the radiographic navigation software to be used during operation and postoperative period. The latent period ranged from 3 to 20 days, the correction period ranged from 7 to 20 days and the consolidation period ranged from 39 to 81 days. It was concluded that special fixators can be used in dogs with complex antebrachial deformities. CLINICAL SIGNIFICANCE: The ability to perform six axes correction at the same time has a considerable advantage, especially in dogs with complex antebrachial deformities. It is practical to use this fixation system in dogs with antebrachial deformities.

Magnetic Resonance Imaging Safety of Magnetically Controlled Growing Rods in an In Vivo Animal Model.

STUDY DESIGN: Experimental animal study. OBJECTIVE: To investigate the interaction between magnetically controlled growing rods (MCGRs) and magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: Growing rod treatment through serial operations results in adverse effects on the patient and high treatment costs. MCGRs can be lengthened noninvasively in an outpatient setting and with lower treatment costs. When MRI investigation is required, the interaction between MCGRs and MRI is an issue of concern in patients with MCGRs. This study investigated MRI compatibility of MCGRs in an in vivo setting. METHODS: The study was conducted on three sheep. A standard posterior approach was used. One polyaxial pedicle screw at the ends was placed. Two sheep were instrumented unilaterally and one bilaterally with MCGRs. Temperature change was measured using MR-compatible sensors. Thoracic and lumbar MRIs were obtained using a 0.3 T MRI unit. MRI waves were applied for 45 minutes and temperature changes were recorded every 3 minutes. The lengths of the MCGRs were measured and anteroposterior and lateral spine radiographs were obtained pre- and postoperatively. RESULTS: No displacement in the positions of the MCGRs occurred. The lengths of the MCGRs did not change compared with the preoperative length. The ability of the MCGRs to elongate was not impaired after MRI scanning. There was a mean increase in the temperature of the MCGRs by 1.45°C (0.5-2.4°C). The MCGRs had a strong scattering effect on MRI of the related segments. CONCLUSION: This study indicated that lower magnet MRI is safe in an animal model with MCGRs, with no displacement of the rods and no changes in their length, no significant heating, and no adverse effects on the lengthening mechanism but with a significant scattering effect on visualization of the surrounding tissues. Further investigations are needed to clarify the exact distance where an MRI investigation of distant organs may be done without scattering. LEVEL OF EVIDENCE: N/A.

Effects of immobilization and whole-body vibration on rat serum Type I collagen turnover.

OBJECTIVE: The aim of this study was to investigate the effects of short-term, high-magnitude whole-body vibration (WBV) on serum type I collagen turnover in immobilized rats. MATERIALS AND METHODS: Thirty Wistar albino rats were randomly divided into the following 5 groups: immobilization (IS), immobilization + remobilization (IR), immobilization + WBV (IV), control (C), and WBV control (CV). Immobilization was achieved by casting from the crista iliaca anterior superior to the lower part of the foot for 2 weeks. The applied WBV protocol involved a frequency of 45 Hz and amplitude of 3 mm for 7 days starting a day after the end of the immobilization period. Serum type I collagen turnover markers were measured by using ELISA kits. RESULTS: Serum NH2-terminal propeptide of type I collagen (PINP) levels were significantly lower in the immobilization groups (p < 0.02) compared with the control groups. Although WBV improved PINP levels in the control groups, there were no differences in PINP levels among the immobilization groups. Similarly, serum COOH-terminal telopeptide of type I collagen (CTX) levels were higher in the WBV controls than their own controls (p < 0,05). Immobilization led to deterioration of tendon tissue, as observed by histopathological analysis with a transmission electron microscope. CONCLUSION: Although 1 week of WBV had a positive effect on type I collagen turnover in controls, it is not an efficient method for repairing tissue damage in the early stage following immobilization.

In Vivo Healing Effects of Ankaferd Blood Stopper on the Residual Pancreatic Tissue in a Swine Model of Distal Pancreatectomy.

The aim of this study was to determine whether intraoperative Ankaferd blood stopper (ABS) application into the pancreatic channel and to the pancreatic remnant surface following distal pancreatectomy can or cannot prevent postoperative pancreatic fistula formation. Three pigs underwent distal pancreatectomy under general anesthesia. In two of the pigs, 0.5 ml of ABS was applied to the stump surface area after adding 0.5 ml of ABS into the pancreatic channel. The remaining one animal served as the control. The pigs were sacrificed on the seventh postoperative day for autopsy. The pancreatic remnants from the animals were then taken for histopathological analyses. It was observed that the oral intake had been broken and abdominal distention had developed in the control pig following on the third postoperative day. However, no significant clinical changes were observed in the ABS-applied pigs. In the autopsy, it was found that the control pig had generalized peritonitis with pancreatic necrosis. On the other hand, the ABS-applied pigs had either macroscopically and microscopically normal pancreatic tissue architecture with an occluded Wirsung duct at the pancreatic stump. It was concluded that application of ABS on the transected surface and into the pancreatic channel could prevent pancreatic fistula formation and improve wound healing in the residual pancreatic tissue following distal pancreatectomy.

Effect of intraoperative PEEP application on colonic anastomoses healing: An experimental animal study.

PURPOSE: This study aimed to assess the effect of intraoperative PEEP intervention on the healing of colonic anastomoses in rabbits. MATERIALS AND METHODS: Thirty-two New Zealand type male rabbits were divided into two groups of sixteen animals each. Following ventilation with tracheostomy, colonic resection and anastomosis were performed in both groups. While 10 cm H2O PEEP level was applied in Group I (PEEP), Group II (ZEEP) was ventilated without PEEP throughout the surgery. Half of the both PEEP and ZEEP group animals were killed on the third postoperative day, while the remaining half on the seventh. Anastomotic bursting pressures, the tissue concentrations in hydroxyproline, and histological assessments were performed. Besides, intraoperative oxygen saturation and postoperative arterial blood gas parameters were also compared. RESULTS: On the first postoperative day, both arterial oxygen tension (PO2) and oxygen saturation (SO2) in the PEEP group were significantly higher than in the ZEEP group. On the seventh postoperative day, the bursting pressures of the anastomoses were significantly higher in the PEEP group, however the hydroxyproline content was significantly lower in the PEEP group than that in the ZEEP group. At day 7, PEEP group was significantly associated with increased neoangiogenesis compared with the ZEEP group. CONCLUSION: The anastomotic healing process is positively influenced by the intraoperative PEEP application.

Thermal necrosis induced by electrocauterization as a local adjuvant therapy in local aggressive bone tumors, what is the safe limit for surgical margins? An experimental study.

OBJECTIVE: In the current study, it was aimed to investigate the temperature change in the cavity wall and pathologic necrosis occurred during cauterization, which was applied at different voltages and time intervals. MATERIALS AND METHODS: The right tibias of 32 male rabbits were used. Three 2-mm-diameter holes were created on the cortical surface of the tibia using a hand-held drill. Using an electrocautery device, 55 mV was applied for 3 and 5 s and 65 mV was applied for 3 and 5 s. Maximum temperatures at 3 and 6 mm distance from the application site were measured. Biopsy specimens obtained at 3 and 6 mm distance from the application site were evaluated microscopically for bone cell viability and periosteal necrosis. RESULTS: Thirty-two rabbits were divided into four groups. In all groups, periosteal bone cells located at the region, extending from the application site to 3 mm distance, died. In this region, application of 55 mV for 3 s caused peripheral necrosis. There were significant differences between the four groups in terms of maximum temperatures measured at 3 mm distance from the application site (p = 0.027). On the other hand, no significant differences were noted between the four groups in terms of maximum temperatures measured at 6 mm distance from the application site (p > 0.05). CONCLUSIONS: Cauterization of the cavity wall in the spray mode at 55 mV for 3 s after tumor resection caused necrosis in the cavity wall, extending from the application site to 3 mm distance. LEVEL OF EVIDENCE: Experimental animal study, Level II.

Evaluation of sericin/collagen membranes as prospective wound dressing biomaterial.

Sericin, a silk protein, has high potential for use in biomedical applications. In this study, wound dressing membranes of Sericin (S) and Collagen (C) were prepared by glutaraldehyde cross-linking at S/C; 2:1, 1:1, 1:2, and 0:1 weight ratios. They were stable in water for 4 weeks. However, increasing the proportion of sericin had decreasing effect on the membrane stability. Water swelling property of membranes was enhanced with sericin. The highest water swelling was obtained in 1:1 group (9.06 g/g), but increasing collagen or sericin content in the membranes had a diminishing effect. Highest water vapor transmission rate was obtained with 1:2 group (1013.80 g/m(2)/day). Oxygen permeability results showed that 1:2 (7.67 mg/L) and 2:1 (7.85 mg/L) S/C groups were better than the other groups. While sericin decreased the tensile strength and elongation of membranes, it increased modulus. Sericin also increased brittleness of membranes, but their UTS range (24.93-44.92 MPa) was still suitable for a wound dressing. Membranes were not penetrable to microorganisms. Cytotoxicity studies showed that fibroblasts and keratinocytes attached and gained their characteristic morphologies. They also proliferated on membranes significantly. After 1 week of subcutaneous implantation, a fibrous capsule formed around all membranes with an acute inflammation. Sericin containing membranes showed signs of degradation (at 2nd week), while collagen only membranes remained largely intact. Eventually, sericin containing membranes degraded in 3 weeks with moderate inflammatory response. Overall results suggest that sericin/collagen membranes would be favorable as wound dressing material when sericin ratio is less than or equal to the collagen component.

The effects of the synovium on chondrocyte growth: an experimental study.

PURPOSE: The objective of this study was to evaluate the effects of synovium on the proliferation of the cartilage tissue and chondrocytes using a rabbit knee model as an in vivo synovial culture medium. METHODS: Twelve New Zealand rabbits were used as the animal model in this investigation. Standard size chondral and osteochondral cartilage grafts were taken from, respectively, the left and right knees of all the animals. Two groups of 6 animals were formed: in Group I (synovium group), grafts were placed into the synovial tissue and in group II (patellar tendon group) behind the patellar tendon of the corresponding knees. After 4 months, samples were collected and evaluated macroscopically by measuring their dimensions (vertical = D1, horizontal = D2, and depth = D3) and volumes, and histologically by counting the chondrocyte number using camera lucida method. RESULTS: Macroscopically, the increase in average D1, D2, and D3 measurements and volume in the osteochondral specimens were significantly higher compared to the chondral specimens in both groups (P < 0.05). However, no significant difference was observed between the two groups in terms of macroscopic values. Histologically, the mean chondrocyte counts in osteochondral and chondral specimens for Group I (synovium) were 20.2 and 18.1, and for Group II (patellar tendon) were 18.7 and 15.6, respectively. The mean number of chondrocytes was found to be significantly higher in osteochondral specimens than that of chondral specimens in either group (P < 0.05). Overall average chondrocyte count was significantly higher for Group I compared to Group II (P < 0.05). CONCLUSION: Transplantation of the cartilage grafts into the synovial tissue in rabbit knees significantly enhanced the chondrocyte production compared with the group where the grafts were transplanted into intra-articular patellar tendon. The results of this study indicate that native synovial tissue may have the potential to be used as an in vivo culture medium for osteochondral tissue growth.

Evaluation of a haemostatic agent in rabbits.

Topical hemostatic agents are applied locally to areas of injured vascular endothelium to control local bleeding. Ankaferd Blood Stopper (ABS) has gained approval in Turkey and Bosnia-Herzegovina as a topical haemostatic agent for external post-surgical and post-dental surgery bleeding. The safety of topical use of ABS has been demonstrated in numerous in vitro and in vivo animal models, as well as in a clinical Phase I trial in humans. ABS, besides its haemostatic activity, also has in vitro anti-infectious and anti-neoplastic effects. To assess potential detrimental effects of intravenous administration of ABS into intact systemic circulation in a rabbit experimental model, one milliliter of ABS was administered intravenously into the systemic circulation of twelve rabbits which were included in the study via the marginal ear vein. Animals were observed for 1 hr before euthanasia was performed by administering 40 mg of intracardiac suxamethonium chloride. In the event of death (cardiopulmonary arrest) before the end of the planned observation period of 60 minutes, time of death was recorded and histopathological examination of the liver and spleen was commenced. Ten rabbits were alive by the end of the planned observation period, without showing any clear signs of discomfort, whereas two animals died within five minutes after systemic administration of intravenous ABS. Postmortem histopathological examination of the livers and spleens of all animals' revealed findings consistent with hepatic venous outflow obstruction. Systemic intravascular administration of ABS into intact vascular endothelium should never be performed in any setting. Further experimental and clinical studies on this liquid hemostatic agent should proceed by accepting ABS as purely a topical haemostatic agent, to be applied solely to areas of injured vascular endothelium.

Biomechanical and histological outcome of combined raloxifene-estrogen therapy on skeletal and reproductive tissues.

Estrogen replacement is a potent therapy for postmenopausal osteoporosis. However, its carcinogenic effects on breasts and the uterus limit its utilization. Raloxifene has estrogen-like effects on bones without the carcinogenic symptoms on breast or uterine tissue. Their individual effects are well characterized, but the results of their interaction remains elusive. In this work, we investigate the consequences of a combined raloxifene/estrogen therapy on bone and uterus with experimental osteoporosis. 40 Wistar rats began treatment 3 months post-ovariectomy. Estrogen and raloxifene were administered 0.03 mg/kg/day and 1.5mg/kg/day separately and together for 5 times per week for 12 weeks. Biomechanical tests and bone mineral density measurements, histology of uterus, and blood markers were analyzed. The co-administration group had higher toughness and ultimate strength than the ovariectomized controls (P<0.01). E+R had better biomechanical properties than the single treatments; yet the differences were not significant. Uterus histology signified high degeneration in the estrogen group. The raloxifene group had less degeneration but higher vascularization. Less immune reaction and vascularization were observed in the group with combined dosage than in those with individual treatments. Hence, the uterus of the combined treatment had fewer side effects than the ones that were individually treated. Mutual antagonization might be possible between raloxifene and estrogen, and that might have caused a decrease in the adverse effects. Overall, combined therapy might be useful to minimize the individual side effects of raloxifene and estrogen on the uterus and still provide bone strength and toughness.

Oral systemic administration of Ankaferd blood stopper has no short-term toxicity in an in vivo rabbit experimental model.

BACKGROUND: Ankaferd blood stopper (ABS) is a standardized herbal extract obtained from 5 different plants. In Turkey, it has been approved for local topical applications in external postsurgical and postdental surgery bleedings. Ankaferd blood stopper, besides its hemostatic activity, has in vitro anti-infectious and antineoplastic actions. OBJECTIVE: The aim of this study was to assess short-term hematological and biochemical safety following the oral systemic administration of ABS to rabbits. METHODS: Twelve rabbits (aged 6-12 months) were included to test the safety of oral ABS. Animals were divided into 4 groups, which had ABS administered orally at doses of 1, 3, 6, and 9 mL, irrespective of their weight. The general well-being and feeding patterns of the animals were observed for a period of 7 days. Blood samples (5.5 mL) were obtained just before oral administration, on days 1 and 4. RESULTS: During the observation period of 7 days, none of the animals showed any abnormal behavior or deviation from the normal. Acute mucosal toxicity, hematotoxicity, hepatotoxicity, nephrotoxicity, and biochemical toxicity were not observed during the short-term follow-up of the animals. CONCLUSIONS: No signs of toxicity were observed in rabbits during short-term study with oral ABS administration.

Ultrastructural and morphological analyses of the in vitro and in vivo hemostatic effects of Ankaferd Blood Stopper.

Ultrastructural and morphological analyses of a novel hemostatic agent, Ankaferd Blood Stopper (ABS), in comparison to its in vitro and in vivo hemostatic effects were investigated. High-resolution scanning electron microscopy (SEM) images accompanied with morphological analysis after topical application of ABS revealed a very rapid (<1 second) protein network formation within concurrent vital erythroid aggregation covering the classical coagulation cascade. Histopathological examination revealed similar in vivo ABS-induced hemostatic network at the porcine hepatic tissue injury model. Instantaneous control of bleeding was achieved in human surgery-induced dental tissue injury associated with primary and secondary hemostatic abnormalities. Ankaferd Blood Stopper could hold a great premise for clinical management of surgery bleedings as well as immediate cessation of bleeding on external injuries based on upcoming clinical trials.

Hemostatic efficacy of Ankaferd Blood Stopper in a swine bleeding model.

OBJECTIVE: The purpose of this study was to show the hemostatic effect of spray, solution and tampon forms of Ankaferd Blood Stopper (ABS), a unique medicinal plant extract historically used as a hemostatic agent in Turkish folklore medicine, in a porcine bleeding model. MATERIALS AND METHODS: Two 1-year-old pigs were used as bleeding models for superficial and deep skin lacerations, grade II liver and spleen injuries, grade II saphenous vein injury and grade IV saphenous artery injury. Spray, solution or tampon forms of ABS were applied after continuing bleeding was confirmed. The primary outcome was time to hemostasis. Volume of blood loss was not measured. The pigs were euthanized at the end of the experiment. RESULTS: Spray or direct application of ABS solution resulted in instant control of bleeding in superficial and deep skin lacerations as well as puncture wounds of the liver. A 40-second application of ABS tampon was sufficient to stop bleeding of skin lacerations, while 1.5- and 3.5-min applications were used to control hemorrhage from the saphenous vein and artery, respectively. No rebleeding was observed once hemostasis was achieved. However, repeated applications of ABS solution and tampon were only temporarily effective in the hemostasis of spleen injury. CONCLUSIONS: The data showed that ABS was an effective hemostatic agent for superficial and deep skin lacerations and minor/moderate trauma injuries in a porcine bleeding model.

Enhanced efficacy of diclofenac sodium-loaded lipogelosome formulation in intra-articular treatment of rheumatoid arthritis.

Recent research into the complex and varied components of rheumatoid arthritis (RA) is leading to the development of more effective targets for pharmaceutical approach than even before. Current treatment of RA frequently includes the use of nonsteroidal anti-inflammatory drugs, such as Diclofenac sodium (DFNa) in spite of the severe adverse effects. Local application and incorporation of the drugs in liposome based formulations may reduce those side effects and improve the efficacy of drugs by reducing the availability of them in systemic circulation and increasing accumulation and retention time in the sites of inflammation. Herein, anti-inflammatory efficacy of the DFNa containing lipogelosome formulations (L1J1) was evaluated and found that L1J1 elicits a better anti-inflammatory efficacy after a single dose i.a. administration in comparison with commercial product, VE-CP, which is used topically. Histopathological examination of the opened joints showed that joints treated with L1J1, had significantly (p < 0.05) lower scores than contra lateral control joints for inflammatory changes in the synovium. These results were also confirmed by biodistribution studies.

Effects of vascular bundle implantation on autograft, fresh-frozen allograft, and xenograft incorporation in a rabbit model.

This study examined the effects of vascular bundle implantation into a bone graft. Vascularized and nonvascularized autografts, allografts, and xenografts were placed inside defects in the proximal tibia in rabbits. Evaluation using radiographs, magnetic resonance imaging, bone scintigraphy, and microscopy showed autografts fused more rapidly than allografts and xenografts, and the majority of the vascularized grafts were incorporated completely. Autografts emerged as the gold standard. These findings indicate vessel implantation enhances and accelerates vascularization, new bone formation, and incorporation in autografts, allografts, and xenografts.

Thrombus localization by using streptokinase containing vesicular systems.

Our research focused on the preparation of vesicular drug delivery systems, such as liposomes, noisomes, and sphingosomes, for achieving slow release of entrapped proteins in the circulation to increase half-life, to mask immunogenic properties, and to protect against loss of enzymatic activity. We prepared, characterized, and monitored the biodistribution of three types of vesicular systems (liposomes, niosomes, and sphingosomes) containing streptokinase. For biodistribution stuides, radiolabelled streptokinase dispersions were injected into the ear vein of female rabbits in the weight of 2.5-3 kg weight. Following the application, rabbits were sacrificed, then organs of these animals were removed and radioactivity of organs was measured by well-type gamma counter. The comparison of the biodistribution results of the free streptokinase with the streptokinase vesicles showed that incorporation of the enzyme into the vesicles changed the biodistribution of the drug and by the entrapment of the streptokinase in the vesicles, thrombus uptake and imaging quality were improved.

Scintigraphic imaging of radiolabelled drug delivery systems in rabbits with arthritis.

This paper describes a novel approach for designing drug delivery systems for intra-articular (i.a.) treatment of rheumatoid arthritis. Retention of these systems was evaluated by radiolabeling with Tc-99m and gamma scintigraphy in arthritic rabbits. Liposome, niosome, lipogelosome and niogelosome formulations of Diclofenac Sodium (DFNa) have been prepared and drug release properties and in vitro characterisation studies have been carried out. According to characterisation results L1 (DMPC: CHOL: DCP (7:1:2)), L1J1 (DMPC: CHOL: DCP (7:1:2) in C-940 1:1 (w/w)), N (SUR I: CHOL: DCP (7:1:2)) and NJ1 (SUR I: CHOL: DCP (7:1:2) in C-940 1:1 (w/w)) formulations were chosen for the further studies. Retention time of these formulations was evaluated by gamma scintigraphic imaging studies. Rabbits with antigen-induced arthritis were injected intra-articularly with Tc-99m labelled drug delivery systems. Serial scintigraphic images were obtained to investigate the retentions of labelled drug delivery systems in the arthritic joints and choose a suitable formulation for the treatment protocol of arthritis. At the end of the scintigraphic imaging studies it was observed that radiolabelled lipogelosome formulation containing DFNa (L1J1) retained much longer in the experimentally arthritic knee joints of the rabbits. This formulation was used for the treatment protocol of arthritis. Mono articular arthritis was induced in the knee joints of rabbits and it was monitored at regular time intervals by measuring changes in knee joint diameter. Also macroscopic and histopathologic evaluations were performed for further evaluation of arthritis. Great retention of DFNa in the arthritic joint might reduce potential adverse systemic effects of the drug because of local administration into the diseased area. It appeared to be a promising drug delivery system for intra-articular drug delivery.

In vivo behaviour of vesicular urokinase.

Thromboembolic diseases including deep vein thrombus (DVT) are major causes of morbidity and mortality. Detection of DVT in low extremities is difficult. There are some accepted imaging techniques in clinic but most of them have several disadvantages limiting their effective use. Because of this, researchers are still performed to develop a rapid, specific means of detecting and/or imaging venous thrombi-based on the changing composition of the thrombus. Urokinase, fibrinolytic enzyme isolated form human urine, is a direct activator of plasminogen. In thrombus formation, plasminogen seems to be trapped in or absorbed onto fibrin matrix thus leading to a localised concentration of plasminogen. This suggests that radiolabelled urokinase would be a suitable compound for the detection of thrombi. The most important disadvantage of this enzyme is short plasma half life. To overcome this problem, it was decided to encapsulate the enzyme in drug delivery systems such as liposomes, niosomes or sphingosomes. In this study, we prepared, characterized and monitored the biodistribution of three types of vesicular systems containing urokinase. All types of prepared vesicles show in vitro an acceptable encapsulation, stability and release profile. Thrombus uptake was increased by encapsulation of urokinase into vesicles.