Functional outcome and quality of life following resection of the proximal humerus performed for musculoskeletal tumors and reconstruction done by four different methods

INTRODUCTION

The proximal humerus is a frequent site for both primary and secondary bone tumors. Several options are currently available to reconstruct the resected humerus, but there is no consensus regarding optimal reconstruction. The aim of this retrospective study was to compare the functional outcome, complications and patient compliance following four different types of reconstructive techniques.

MATERIAL AND METHODS

The authors performed 90 proximal humerus resections due to primary and secondary bone tumors over the past 21 years. Four different procedures were performed for reconstruction following the resection: fibula autograft transplantation, osteoarticular allograft implantation, modular tumor endoprosthesis (hemiarthroplasty) and reconstruction of the defect with a reverse shoulder prosthesis-allograft composite. A retrospective analysis of the complications and patient's physical status was performed. Functional outcome and life quality was evaluated by using the MSTS and SF-36 scores.

RESULTS

The best range of motion was observed following arthroplasty with a reverse shoulder prosthesis-homograft composite followed by a fibula autograft reconstruction. Revision surgery was required due to major complications most frequently in the osteoarticular allograft group, followed by the reverse shoulder prosthesis-allograft composite group, the autologous fibula transplantation group; the tumor endoprosthesis hemiarthroplasty group had superior results regarding revision surgery (40, 25, 24 and 14% respectively). MSTS was 84% on average for the reverse shoulder prosthesis-allograft composite group, 70% for the autologous fibula group, 67% for the anatomical hemiarthroplasty group and 64% for the osteoartricular allograft group. Using the SF-36 questionnaire for assessment no significant differences were found between the four groups regarding quality of life.

DISCUSSION

Based on the results of our study the best functional performance (range of motion and patient compliance) was achieved in the a reverse prosthesis-allograft combination group-in cases where the axillary nerve could be spared. The use of an osteoarticular allograft resulted in unsatisfying functional results and high complication rates, therefore we do not recommend it as a reconstructive method following resection of the proximal humerus due to either primary or metastatic bone tumors. Young patients who have good life expectancy but a small humerus or intramedullar cavity reconstruction by implantation of a fibula autograft is a good option. For patients with a poor prognosis (i.g. bone metastases) or in cases where the axillary nerve must be sacrificed, hemiarthroplasty using a tumor endoprosthesis was found to have acceptable results with a low complication rate. According to the MSTS and SF-36 functional scoring systems patients compliance was nearly identical following all four types of reconstruction techniques; the underlying cause may be the complexity of the shoulder girdle. However, we recommend the implantation of a reverse shoulder prosthesis-allograft whenever indication is appropriate, as it has been demonstrated to provide excellent functional outcomes, especially in young adults.

N-Acetylcysteine-Loaded Magnetic Nanoparticles for Magnetic Resonance Imaging

Acute respiratory distress syndrome (ARDS) is a life-threatening condition characterized by the rapid onset of lung inflammation Therefore, monitoring the spatial distribution of the drug directly administered to heterogeneously damaged lungs is desirable. In this work, we focus on optimizing the drug N-acetylcysteine (NAC) adsorption on poly-l-lysine-modified magnetic nanoparticles (PLLMNPs) to monitor the drug spatial distribution in the lungs using magnetic resonance imaging (MRI) techniques. The physicochemical characterizations of the samples were conducted in terms of morphology, particle size distributions, surface charge, and magnetic properties followed by the thermogravimetric quantification of NAC coating and cytotoxicity experiments. The sample with the theoretical NAC loading concentration of 0.25 mg/mL was selected as an optimum due to the hydrodynamic nanoparticle size of 154 nm, the surface charge of +32 mV, good stability, and no cytotoxicity. Finally, MRI relaxometry confirmed the suitability of the sample to study the spatial distribution of the drug in vivo using MRI protocols. We showed the prevailing transverse relaxation with high transverse relaxivity values and a high r₂⁽*⁾/r₁ ratio, causing visible hypointensity in the final MRI signal. Furthermore, NAC adsorption significantly affects the relaxation properties of PLLMNPs, which can help monitor drug release in vitro/in vivo.

Development of Positively Charged Poly-L-Lysine Magnetic Nanoparticles as Potential MRI Contrast Agent

A colloidal solution of magnetic nanoparticles (MNPs) modified with biocompatible positively charged poly-L-lysine (PLL) with an oleate (OL) layer employed as an initial coating was produced as a potential MRI contrast agent. The effect of various PLL/MNPs' mass ratios on the samples' hydrodynamic diameter, zeta potential, and isoelectric point (IEP) was studied by the dynamic light-scattering method. The optimal mass ratio for MNPs' surface coating was 0.5 (sample PLL_0.5-OL-MNPs). The average hydrodynamic particle size in the sample of PLL_0.5-OL-MNPs was 124.4 ± 1.4 nm, and in the PLL-unmodified nanoparticles, it was 60.9 ± 0.2 nm, indicating that the OL-MNPs' surface became covered by PLL. Next, the typical characteristics of the superparamagnetic behavior were observed in all samples. In addition, the decrease in saturation magnetizations from 66.9 Am²/kg for MNPs to 35.9 and 31.6 Am²/kg for sample OL-MNPs and PLL_0.5-OL-MNPs also confirmed successful PLL adsorption. Moreover, we show that both OL-MNPs and PLL_0.5-OL-MNPs exhibit excellent MRI relaxivity properties and a very high r₂⁽*⁾/r₁ ratio, which is very desirable in biomedical applications with required MRI contrast enhancement. The PLL coating itself appears to be the crucial factor in enhancing the relaxivity of MNPs in MRI relaxometry.

Targeting of carbonic anhydrase IX-positive cancer cells by glycine-coated superparamagnetic nanoparticles

Antibody-modified magnetic nanoparticles were prepared to study their cellular uptake in 3D multicellular spheroidal cell cultures. For this purpose, carbonic anhydrase IX specific monoclonal antibody VII/20 was selected to conjugate on the surface of positively charged glycine coated magnetic nanoparticles in a form of a stable magnetic fluid. In this work, glycine-functionalized magnetic nanoparticles were characterized by different methods. X-ray photoelectron analysis confirmed the binding of glycine to the magnetic nanoparticles, and quantification of the glycine coating on the surface of the magnetic nanoparticles was conducted by thermogravimetric analysis. The optimal weight ratio of glycine to magnetic nanoparticles was determined to be 5 showing good colloid stability due to the high surface charge density of protonated glycine coating shown by the great zeta potential (⁓40 mV). The antibody conjugation to the functionalized magnetic nanoparticles was performed at an antibody to magnetic nanoparticles weight ratio equal to 0.5. Applications of antibody-modified magnetic nanoparticles in cancer therapy rely on their ability to specifically target cancer tissues and enter the tumour intracellular space. Here, we show that antibody coupled nanoparticle internalization was triggered by selective binding to tumour cells expressing hypoxic marker carbonic anhydrase IX. Moreover, our results confirmed specific penetration of conjugated nanoparticles into the tumour cell spheroids.

MRI Relaxivity Changes of the Magnetic Nanoparticles Induced by Different Amino Acid Coatings

In this study, we analysed the physico-chemical properties of positively charged magnetic fluids consisting of magnetic nanoparticles (MNPs) functionalised by different amino acids (AAs): glycine (Gly), lysine (Lys) and tryptophan (Trp), and the influence of AA-MNP complexes on the MRI relaxivity. We found that the AA coating affects the size of dispersed particles and isoelectric point, as well as the zeta potential of AA-MNPs differently, depending on the AA selected. Moreover, we showed that a change in hydrodynamic diameter results in a change to the relaxivity of AA-MNP complexes. On the one hand, we observed a decrease in the relaxivity values, r₁ and r₂, with an increase in hydrodynamic diameter (the relaxivity of r₁ and r₂ were comparable with commercially available contrast agents); on the other hand, we observed an increase in r₂* value with an increase in hydrodynamic size. These findings provide an interesting preliminary look at the impact of AA coating on the relaxivity properties of AA-MNP complexes, with a specific application in molecular contrast imaging originating from magnetic nanoparticles and magnetic resonance techniques.

Schizophrenia: redox regulation and volume neurotransmission

Here, we show that volume neurotransmission and the redox property of dopamine, as well as redox-regulated processes at glutamate receptors, can contribute significantly to our understanding of schizophrenia. Namely, volume neurotransmission may play a key role in the development of dysconnectivity between brain regions in schizophrenic patients, which can cause abnormal modulation of NMDA-dependent synaptic plasticity and produce local paroxysms in deafferented neural areas. During synaptic transmission, neuroredox regulations have fundamental functions, which involve the excellent antioxidant properties and nonsynaptic neurotransmission of dopamine. It is possible that the effect of redox-linked volume neurotransmission (diffusion) of dopamine is not as exact as communication by the classical synaptic mechanism, so approaching the study of complex schizophrenic mechanisms from this perspective may be beneficial. However, knowledge of redox signal processes, including the sources and molecular targets of reactive species, is essential for understanding the physiological and pathophysiological signal pathways in cells and the brain, as well as for pharmacological design of various types of new drugs.

Visible light induced ocular delayed bioluminescence as a possible origin of negative afterimage

The delayed luminescence of biological tissues is an ultraweak reemission of absorbed photons after exposure to external monochromatic or white light illumination. Recently, Wang, Bókkon, Dai and Antal (2011) [10] presented the first experimental proof of the existence of spontaneous ultraweak biophoton emission and visible light induced delayed ultraweak photon emission from in vitro freshly isolated rat's whole eye, lens, vitreous humor and retina. Here, we suggest that the photobiophysical source of negative afterimage can also occur within the eye by delayed bioluminescent photons. In other words, when we stare at a colored (or white) image for few seconds, external photons can induce excited electronic states within different parts of the eye that is followed by a delayed reemission of absorbed photons for several seconds. Finally, these reemitted photons can be absorbed by non-bleached photoreceptors that produce a negative afterimage. Although this suggests the photobiophysical source of negative afterimages is related retinal mechanisms, cortical neurons have also essential contribution in the interpretation and modulation of negative afterimages.

New formulation of in situ gelling Metolose-based liquid suppository

CONTEXT

An in situ gelling liquid suppository is liquid at room temperature but forms a gel at body temperature. In our work, Metolose® SM-4000 (methylcellulose) is studied that basically shows thermal gelation at 68°C (2%, w/w).

OBJECTIVE

The objective was to study the potency of different factors (concentration, pH, additives) to change the value of thermal gelation temperature (T (t)) for Metolose® to form an in situ gelling liquid suppository.

MATERIALS AND METHODS

We studied the effect of Metolose® concentration, pH, and salts (sodium chloride, potassium chloride, sodium hydrogen carbonate, and sodium monohydrogen phosphate) on T (t) by viscosimetry. To choose the appropriate compound, in vitro drug release was examined. Rectal safety test was performed on rats in vivo after 12-hour application.

RESULTS

Increasing the Metolose® concentrations (0.5-4%, w/w), T (t) can be decreased, but it also altered the consistency of gel. pH does not affect the T (t). The water-soluble salts allowed reducing the gelation temperature to 37°C. Sodium monohydrogen phosphate in 4.5% concentration was found to be the most appropriate. The impact of examined factors on in vitro drug release of piroxicam from the in situ-formed gel was characterized according to Fickian diffusion. Metolose® and the chosen salt did not cause any morphological damage on the rectal tissues.

DISCUSSION

According to our study, Metolose® has the physical and chemical potential to be used as base for liquid suppositories.

In vitro food-drug interaction study: Which milk component has a decreasing effect on the bioavailability of ciprofloxacin?

The purpose of the present work was developing an in vitro dissolution test to highlight the possible molecular background causing ciprofloxacin (CPFX)-milk interaction. The in vitro dissolution of CPFX from film-coated tablets (Ciprinol) 500mg) was examined at different pH values, simulating certain parts of the gastrointestinal tract, in the presence of water, low-fat milk, casein- or calcium enriched water. In order to determine the amount of dissolved CPFX, solid phase extraction sample preparation followed by high performance liquid chromatography coupled with mass spectrometry was applied. Comparing the dissolution efficiency values in various media, it can be concluded, that casein has a more pronounced effect on the absorbable amount of the antibiotic at each pH value studied, than calcium. In the case of concomitant intake of CPFX film-coated tablet and milk or other dairy products not only the complexation with calcium, but also the adsorption of CPFX on the surface of proteins decreases the absorbable amount of CPFX.

Potential application of Metolose in a thermoresponsive transdermal therapeutic system

The purpose of the present study was to formulate a novel thermoresponsive membrane controlled therapeutic system from Metolose for possible transdermal application. Metolose gel shows thermal gelation property, which can be characterized by two (T(1), T(2)) temperatures. A sharp decrease of viscosity can be measured at T(1), but gelation can be observed at T(2). Different types of Metolose polymers were compared considering their thermoresponsive behaviour. Only thermal gelation was observed in the case of Metolose SM, while Metolose SH showed a sudden decrease of viscosity at T(1). Since this temperature is above the body temperature, so it should be shifted to the skin temperature in case of possible transdermal application. Modulation of thermoresponsibility was followed by rheological method, and the thermoresponsive drug release from Metolose gel was studied by static liberation test. Our results demonstrated that the effect of different salts (NaCl, NaHCO(3), KCl) of various concentrations in Metolose SH gel reduced T(1) to the skin temperature, which enabled enhanced drug release.

Comparison of the degenerative changes in weight-bearing joints following cementing or grafting techniques in giant cell tumour patients: medium-term results

The aim of this retrospective study was to compare and assess the effect of bone grafting and cementing techniques--two common applications used in the treatment of subchondral giant cell tumours of bone (GCTs)--on the development of degenerative changes in the weight-bearing joints of the lower extremity. Eighty patients were included in this follow-up study, 44 of whom underwent curettage followed by bone grafting, and 36 who had curettage followed by cementation. At the 24-month post-operative examination, significantly less degenerative change was found in patients with bone cement than in those with bone grafting. At the 50-month and later (range: 50-148 months) post-operative examination, however, no significant differences were found between the two groups, indicating that there was a significant acceleration of degenerative changes in the cemented group after the 24-month follow-up.

Application of sucrose fatty acid esters in transdermal therapeutic systems

Transdermal therapeutic systems (TTSs) were studied applying different sucrose fatty acid esters (SEs) as drug delivery agents. Matrix and membrane controlled TTSs were prepared and compared. Membrane was made from a methacrylic polymer (Eudragit NE) of pH independent permeability which can achieve diffusion controlled drug liberation. Model drug was a water soluble beta-blocker, metoprolol, which has short biological half-life, so applying it in a TTS, the duration of its action could be prolonged. Sucrose fatty acid esters of different fatty acid chain lengths and consequently different hydrophilic-lipophilic balance (HLB) values were studied considering their effect on the metoprolol release from TTSs. Different mathematical models were applied for the evaluation of the release process. The results of the in vitro studies indicated that SEs of shorter fatty acid chain length and higher HLB value increased the amount of released drug about 10 times. SEs could be promising agents in transdermal therapeutic systems to control the drug release and cutaneous absorption.

Quantitative estimation of film forming polymer–plasticizer interactions by the Lorentz–Lorenz Law

Molar refraction as well as refractive index has many uses. Beyond confirming the identity and purity of a compound, determination of molecular structure and molecular weight, molar refraction is also used in other estimation schemes, such as in critical properties, surface tension, solubility parameter, molecular polarizability, dipole moment, etc. In the present study molar refraction values of polymer dispersions were determined for the quantitative estimation of film forming polymer-plasticizer interactions. Information can be obtained concerning the extent of interaction between the polymer and the plasticizer from the calculation of molar refraction values of film forming polymer dispersions containing plasticizer.

Functional outcome and life quality after endoprosthetic reconstruction following malignant tumours around the knee

Between 1993 and 2002, we treated 43 patients with malignant musculoskeletal tumours of the knee region. All patients had partial resection of the femur or tibia together with endoprosthetic replacement. We were able to follow-up 23 patients with an average follow-up of 30 (12-97) months. Complications occurred in ten cases, of which one was a case of local recurrence. Most of the patients were completely satisfied with their condition, with a decreased walking distance as the only notable restriction. There was no correlation between the functional outcome and life quality assessment and the type of the implanted prosthesis, length of resected bone and type of resection. However, patients with tumours in the distal femur had significantly better functional and life quality outcome than those with a proximal tibial tumour.

Surgical treatment and prognostic factors in giant-cell tumor of bone

The rate of local recurrence in the giant-cell tumor of bone (GCT) is influenced by many factors. GCT aggressiveness is related to mitotic activity, aneuploidy of tumor cells, chromosomal abnormality, excessive metalloproteinase expression and alterations in different oncogenes. Statistically, there was no correlation between the recurrence rate and the size and site of tumor, stage of disease and involvement of subchondral bone. However, statistical analysis revealed that the use of adjuvants (phenol, bone cement, etc) and the type of surgical intervention (en block resection versus curettage and grafting) were factors with a prognostic value. Although recurrence or malignant transformation in GCT cannot be predicted yet, about 96% of the patients can be cured. In the majority of cases, recurrences have no fatal consequences for the patient but may lead to various degrees of disability due to repeated and more radical surgical procedures. Joint-sparing surgery and careful curettage with the use of adjuvants should be the treatment of choice whenever possible. In the future, modern instruments of molecular biology will be used to aid the evaluation of primary and recurrent tumors and will have an increasing influence on surgical planning.

The effect of oil as a dietary component on in vitro dissolution of an acid-labile drug

The non-benzodiazepine-like anxiolytic agent deramiclane fumarate (EGIA-3886) was used to demonstrate that the presence of high oil/fat content in dissolution media serves as a barrier against accelerated drug degradation in acidic media.

[Biopharmaceutical considerations of dissolution testing used as a prognostic tool for oral drug adsorption]

Drug dissolution is a prerequisite to drug absorption and in vivo effectiveness for almost all drugs given in oral solid dosage forms. Drug absorption depends on the dissolution and solubilization of the drug under physiological conditions, and the permeability across the gastrointestinal tract. Because of the critical nature of the first steps, in vitro dissolution may be relevant to the prediction of biological response. Dissolution tests are applied to choose between formulation factors, assess the lot-to-lot quality of a drug product according to the biobatch; and ensure continuing product quality and performance after certain changes (e.g. in the formulation and manufacturing process, site of manufacture, scale-up). The recently developed Biopharmaceutical Classification System (BCS) has several benefits for recognizing how dissolution tests can be designed and which physiological factors have to be taken into consideration for the in vitro evaluation of solid dosage forms. Choice of test conditions (composition, volume and hydrodynamics of dissolution medium) should be based on where the drug is best absorbed in the gastrointestinal tract, and on whether it is administered in fasted or fed state. Duration of test and physiologically representative media can be selected to simulate gastric and intestinal environments according to the permeability profile of the drug, but mimicking in vivo hydrodynamics remains problematic and further research is required. To provide a basis for predicting the likelihood of achieving a successful in vivo-in vitro correlation, this review summarizes the biopharmaceutical considerations of in vivo drug release in accordance with the BCS.

Development of spherical crystals of acetylsalicylic acid for direct tablet-making

The production of spherical crystals has recently gained great attention due to the fact that the crystal habit (form, surface, size, etc.) can be modified during the crystallization process. Spherical crystals of ASA were developed by non-typical and typical spherical crystallization techniques. The non-typical spherical crystallization process (conventional stirred tank method) resulted in few monocrystals and non-spherical crystal agglomerates. The typical spherical crystallization process was carried out by the three solvent-system (ethanol-water-carbon tetrachloride). The products were qualified by morphological study, NIR investigation, salicylic acid content, dissolution rate, studies on flowability, compactibility, cohesivity and tablettability. The results demonstrate that only typical spherical crystallization can be recommended for the production of spherical crystals of ASA. Only product made by this technique shows excellent flow properties and favourable compactibility, cohesiveness and tablettability values.

Mid-foot reconstruction following involvement of five bones by giant cell tumor

We report on a patient who had giant cell tumor involving multiple bones of the mid-foot. The tumor originated from the navicular bone, but also destroyed the cuboid, and all cuneiform bones. This unusual presentation of giant cell tumor presented a therapeutic challenge for the surgeons. The patient was treated with en bloc resection and the bony defect replaced with a massive iliac crest graft which united within 9 months and has remained stable for 7 years without local recurrence, and with excellent function of the foot.

[Results of limb-saving surgery and prognostic factors in patients with osteosarcoma]

Ninety six patients with high-grade osteosarcoma of the extremities were treated between 1986 and 1997 in the authors institution. They were divided into three groups: in group I, all of 75 patients with non-metastatic OS received intensive chemotherapy and underwent surgery. In group II, 9 patients already had metastases at the time of referral. In group III, 12 patients received chemotherapy in delayed or suboptimal form. In group I, local recurrences occurred in 7 per cent (3 patients), metastases in 20 per cent of the patients with limb-saving, whereas these numbers were 3 per cent and 38 per cent in the amputation group. The 5-year disease free survival (DFS) was 72% v 69% in the limb-saving and amputation group, respectively. In groups II and III, 5-year DFS was extremely poor, 10 and 20% only. With univariate analysis, factors having a positive influence on the survival were: tumor volume < 60 cm3, wide or radical surgical margin, distal location of osteosarcoma, cartilagineous ground substance less than 20% and response to chemotherapy. The last 4 variables maintained their significance in the multivariate Cox model as well. Age > 30 showed indirect negative influence on the final outcome (enhanced intolerability to the drugs and less co-operability of the patients etc.). This data confirm the competence of the limb-saving surgery at certain indications beside the amputation.

[Malignant transformation of giant cell tumor in the distal radius. Value of the DNA cytophotometry]

The GCT is a primary bone tumor of intermedia dignity, whereby the forecast of the biological behaviour and outcome is impossible on the base of the conventional histological diagnosis. The authors observed in one of their GCT-patients a malignant transformation of the formerly benign tumor. Through announcement of their case the authors want to call the attention to the importance of the DNA-Cytophotometry and to their possible future additional role in the diagnostics of the GCT and in the prediction of their biological behaviour.

The prognostic significance of DNA cytophotometry and proliferation index (Ki-67) in giant cell tumors of bone

We studied DNA ploidy by smear cytophotometry and proliferation activity by Ki-67 MIB immunohistochemistry in 69 primary and recurrent giant cell tumors (GCT) from 50 randomly selected patients. The obtained results were evaluated with comparisons made to the available clinical data. From the 46 primary tumors 63% showed diploidy and 37% aneuploidy. A significantly (P=0.026) higher recurrence rate (64%) was observed in aneuploid than in diploid tumors (31%). In the course of the recurrences, both the ratio of aneuploid tumors as well as the proliferation index of the tumors increased, though the degree of the latter was non-significant. Aneuploidy did not mean an unambiguous tendency towards malignant transformation; however, a close follow-up of recurrent aneuploid tumors, and wide excision of the recurrence instead of intralesional curettage are the recommended procedures. The DNA cytophotometry and proliferation index of GCTs--as compared to other histologic examinations--are of prognostic value in the evaluation of the recurrence potential of the GCTs.

[Dual fluorescence in situ hybridization analysis of synovial sarcoma]

Synovial sarcoma have (about in 95% of the cases) the specific and characteristic reciprocal chromosomal translocation t(X; 18) (p11.2; q 11.2). Application of dual-colour fluorescence in situ hybridization (FISH) on interphase nuclei to identify the specific translocation has a diagnostic importance for daily pathological practice. For visualisation of the translocated chromosomal fragments of synovial sarcoma cells on imprint smears, chromosome X painting probes and chromosome 18 centromeric probes were used. Our present study indicates that the precise preoperative diagnosis of synovial sarcoma using dual-colour FISH is possible on smears and this possibility (to identify specific chromosomal translocations in soft tissue tumours) is a landmark in the preoperative diagnosis of soft tissue sarcomas.

[Modification of drug release with application of pharmaceutical technological methods]

Pharmaceutical technological methods, which enable the development of controlled release, prolonged action solid oral dosage forms, are of great importance. The purpose of our study was to apply these methods and evaluate the prepared samples. The first type of the samples were individually coated separated particles, prepared by mixing with lubricant to built up a lubricant film layer on the surface of the drug crystals. The next group of the samples were separately coated particles--wall material was wax--prepared using the following two technologies: fluidisation atomisation process and hot-melt coating. The third group of the samples was the matrix type, where the core material was mixed into the molten mass of the thermosoftening natural coating material or into some synthetic polymer film material. In some cases several surface active agents were added to the molten mixture to achieve a modification in the drug release process and the examined parameters of the samples. For the comparative evaluation of the prepared dosage forms drug release determination and kinetical analysis of the process were maintainly used. The surface morphology was examined on the base of scanning electronmicroscopic and optical microscopic studies. Among the physical and physico-chemical studies particle size analysis was carried out and dynamic contact angles of the solid samples as well as the surface tension decreasing effect was measured to determine the modifying properties of surface active excipients. To sum up, our results demonstrate that the economical and environmentally acceptable melt coating technology was justified as applicable advantageously in a large number of cases for the development of controlled release devices of highly watersoluble drug, even the medical substance is an organic compound having adjustable thermostability.

Fibrous dysplasia associated with intramuscular myxoma (Mazabraud's syndrome): a long-term follow-up of three cases

The association between of fibrous dysplasia and intramuscular myxomas is extremely rare. The authors summarize the characteristics of Mazabraud's syndrome, as well as its clinical course on the basis of 24 cases reported in the literature and 3 cases of their own. The syndrome is quite uniform, and mostly occurs in women. Usually the presentation of poliostotic fibrous dysplasia bilaterally in the lower limbs and pelvic bones is followed by the appearance of multifocal intramuscular myxomas in the adjacent muscles, mostly decades later. These hamartomas tend to recur locally or symmetrically in the ipsilateral muscle groups and may reach enormous size without treatment. Malignant transformation (osteosarcoma, fibrosarcoma) on the basis of fibrous dysplasia in Mazabraud's syndrome has been reported in the literature. In our cases, however, in spite of the many recurrences, and the enormous size of the tumours, no malignant transformation was noted in either the fibrous dysplasias or the intramuscular myxomas during the long follow-up time (31 years for fibrous dysplasia and 16 years for myxomas). Early wide surgical excision and a careful long-term follow-up for the often very late recurrences of the myxomas is suggested in Mazabraud's syndrome.

[Evaluation of substrate-binder interfacial interactions]

Substrate-binder interfacial interactions were evaluated on the basis of the physico-chemical and mechanical properties of granules and compressed samples. Linear relationship was found between the breaking strength, the diffuse reflectance and the binder content of the examined granule-systems and compressed samples. The increasing amount of binder in the granules improved the adhesive interaction existing between the substrate and the binder. Our results indicate that the mechanical properties of the single particles as well as of the compressed samples were basically determined by the physico-chemical interactions of the substrate-binder interfacial layer. The qualitative and quantitative evaluation of these interactions has a decisive impact on the formulation and in process control of solid dosage forms of optimal mechanical properties.

Effect of particle size and coating level on the diffuse reflectance of wax matrices

The aim of this study was to examine the influence of particle size and extent of coating on the diffuse-reflectance spectra of wax matrices containing embedded potassium chloride. Near-infrared spectroscopy was used to analyse the diffuse-reflectance characteristics of the prepared multi-particulate matrices without destructive sample preparation. A 2-factor, 3-level face-centred central composite design was selected to construct a second-order polynomial model which described the effect of particle size and amount of coating on the intensity of the diffusely reflected light. A non-linear model was used to demonstrate the effect of the selected parameters on the intensity of the reflected light; good correlation was obtained between experimental and predicted results. The results indicated that the extent of coating and the particle size of the examined systems in the selected particle size-range modified the intensity of the reflected light. It can be concluded that near-infrared spectroscopy is a sensitive means of measuring not only the particle size of powders (substrates and their mixtures), but also that of coated multi-particulate systems.