Thermal degradation of Affinisol HPMC: Optimum Processing Temperatures for Hot Melt Extrusion and 3D Printing.

PURPOSE: Affinisol HPMC HME is a new popular form of hypromellose specifically designed for the hot melt extrusion and 3D printing of pharmaceutical products. However, reports of its thermal stability include only data obtained under inert N2 atmosphere, which is not consistent with the common pharmaceutical practice. Therefore, detailed investigation of its real-life thermal stability in air is paramount for identification of potential risks and limitations during its high-temperature processing. METHODS: In this work, the Affinisol HPMC HME 15LV powder as well as extruded filaments will be investigated by means of thermogravimetry, differential scanning calorimetry and infrared spectroscopy with respect to its thermal stability. RESULTS: The decomposition in N2 was proceeded in accordance with the literature data and manufacturer's specifications: onset at ~260°C at 0.5°C·min-1, single-step mass loss of 90-95%. However, in laboratory or industrial practice, high-temperature processing is performed in the air, where oxidation-induced degradation drastically changes. The thermogravimetric mass loss in air proceeded in three stages: ~ 5% mass loss with onset at 150°C, ~ 70% mass loss at 200°C, and ~ 15% mass loss at 380°C. Diffusion of O2 into the Affinisol material was identified as the rate-determining step. CONCLUSION: For extrusion temperatures ≥170°C, Affinisol exhibits a significant degree of degradation within the 5 min extruder retention time. Hot melt extrusion of pure Affinisol can be comfortably performed below this temperature. Utilization of plasticizers may be necessary for safe 3D printing.

Range of motion after total knee arthroplasty in hemophilic arthropathy.

BACKGROUND: Outcomes of total knee replacement in cases of hemophilic patients are worse than in patients who undergo operations due to osteoarthritis. Previous publications have reported varying rates of complications in hemophilic patients, such as infection and an unsatisfactory range of motion, which have influenced the survival of prostheses. Our retrospective study evaluated the data of hemophilic patients regarding changes in the development of the range of motion. METHODS: The data and clinical outcomes of 72 total knee replacements in 45 patients with hemophilia types A and B were reviewed retrospectively. Patients were operated between 1998 and 2013. All of the patients were systematically followed up to record the range of motion and other parameters before and after surgery. RESULTS: The mean preoperative flexion contracture was 17° ± 11° (range, 0°-40°), and it was 7° ± 12° (range, 0°-60°) postoperatively. The mean flexion of the knee was 73° ± 30° (range, 5°-135°) before the operation and 80° ± 19° (range, 30°-110°) at the last follow-up. The mean range of motion was 56° ± 34° (range, 0°-130°) before the operation and 73° ± 24° (range, 10°-110°) at the last follow-up. CONCLUSIONS: Statistical analysis suggested that the range of motion could be improved until the 9th postoperative week. The patient should be operated on until the flexion contracture reaches 22° to obtain a contracture < 15° postoperatively or until the contracture reaches 12° to obtain less than 5°. The operation generally does not change the flexion of the knee in cases of hemophilic patients, but it reduces the flexion contracture and therefore improves the range.

Serum and bone pentosidine in patients with low impact hip fractures and in patients with advanced osteoarthritis.

BACKGROUND: Femoral neck fractures are a common occurrence in patients suffering from osteoporosis, while intracapsular hip fracture is rare in cases of osteoarthritis of the hip. Previous histomorphometric studies have emphasized the association between bone microarchitecture and the risk of low-impact fractures in osteoarthritis and osteoporosis patients. However, the strength of bone material is also a function of composition of organic bone matrix. In order to compare tissue material properties in these two clinical conditions, serum and bone pentosidine, a non-enzymatic collagen crosslinking element, was measured in patients who suffered a low-impact fracture, and in patients with advanced osteoarthritis. METHODS: The patient population consisted of 70 patients who underwent hemiarthroplasty surgery for a femoral neck fracture, and 41 patients with advanced hip joint osteoarthritis without a history of low- impact fracture, who were indicated for total hip joint replacement. Pentosidine content was analyzed in bone samples and in serum obtained from fracture and osteoarthritis patients using high performance liquid chromatography. RESULTS: Serum and bone concentrations of pentosidine were higher in subjects with hip fractures compared with osteoarthritis after adjustment for age, sex, weight, serum creatinine, and diabetes. A significant positive correlation was found between bone and serum pentosidine in fractured cases. A comparable relationship was also demonstrated for pentosidine levels in serum and bone relative to differentiation of fracture and osteoarthritis cases. CONCLUSIONS: Serum pentosidine can be considered a potential biomarker for identification of subjects with impaired bone quality and bone strength.

Investigation of Brønsted acidity in zeolites through adsorbates with diverse proton affinities.

Understanding the adsorption behavior of base probes in aluminosilicates and its relationship to the intrinsic acidity of Brønsted acid sites (BAS) is essential for the catalytic applications of these materials. In this study, we investigated the adsorption properties of base probe molecules with varying proton affinities (acetonitrile, acetone, formamide, and ammonia) within six different aluminosilicate frameworks (FAU, CHA, IFR, MOR, FER, and TON). An important objective was to propose a robust criterion for evaluating the intrinsic BAS acidity (i.e., state of BAS deprotonation). Based on the bond order conservation principle, the changes in the covalent bond between the aluminum and oxygen carrying the proton provide a good description of the BAS deprotonation state. The ammonia and formamide adsorption cause BAS deprotonation and cannot be used to assess intrinsic BAS acidity. The transition from ion-pair formation, specifically conjugated acid/base interaction, in formamide to strong hydrogen bonding in acetone occurs within a narrow range of base proton affinities (812-822 kJ mol-1). The adsorption of acetonitrile results in the formation of hydrogen-bonded complexes, which exhibit a deprotonation state that follows a similar trend to the deprotonation induced by acetone. This allows for a semi-quantitative comparison of the acidity strengths of BAS within and between the different aluminosilicate frameworks.

Predicting the development of hemophilic arthropathy in patients with hemophilia based on patient age: a retrospective single-center database study.

BACKGROUND: Patients with hemophilia (PWH) develop hemophilic arthropathy of the major joints due to recurrent hemarthrosis. This study retrospectively estimated the age at which PWH may expect to develop hemophilic arthropathy and undergo joint replacement surgery. RESEARCH DESIGN AND METHODS: Using retrospective data from PWH at a Czech orthopedic center, Kaplan Meier analyses were used to estimate the cumulative proportions of patients with hemophilic arthropathy and undergoing joint replacement surgery as a function of age. RESULTS: Based on 1028 joint examinations in 167 PWH, hemophilic arthropathy of the knees, elbows, ankles and hips was estimated to develop by a median age of 48, 51, 52 and 61 years, respectively, with ≈80% of patients having such damage by ≈70 years of age. Hemophilic arthropathy of the shoulder occurred much later (median >80 years). In patients undergoing knee or hip replacement surgery, hemophilic arthropathy of the knee and hip occurred at a median age of ≈50 and ≈60 years, respectively, with replacement surgery occurring at a median of ≈70 and >75 years. CONCLUSIONS: In PWH, the risk of developing hemophilic arthropathy accumulates continuously over the patient's lifetime, allowing predictions about the ages at which such damage and joint replacement surgery may occur.

Hip fracture incidence from 1981 to 2009 in the Czech Republic as a basis of the country-specific FRAX model.

The aim of this study was to calculate rates of hospitalization for hip fracture and the incidence of hip fractures in the Czech Republic over a period of 29 years. A second aim was to use the most recent data to populate a FRAX(®) model for the assessment of fracture probability in individual patients. Data on hospitalizations for hip fracture (1981-2009) and number of women and men with hip fractures (2000-2009) were obtained, and incidences were computed for the entire population ≥50 years of age. Incidence of hospitalization for hip fracture in the Czech population aged ≥50 years increased progressively by calendar year. Age-standardized incidence of hip fractures increased to 2004 but leveled off thereafter and decreased after 2005. Data for hip fracture risk in 2008 and 2009 and the death hazard were used to populate a Czech-specific FRAX model for the computation of 10-year fracture probability. The customized FRAX model, using the verified epidemiological data, will be used to identify patients at increased fracture risk.

Distribution of chondrocytes containing alpha-smooth muscle actin in human normal, osteoarthrotic, and transplanted articular cartilage.

The aim of our study was to evaluate the occurrence of chondrocytes containing alpha-smooth muscle actin in human normal and diseased cartilage. Immunohistochemistry using monoclonal antibodies for alpha-smooth actin, muscle-specific actin, S-100 protein, CD 34, and desmin was performed on samples of human articular cartilage obtained at autopsy following sudden death, during total hip and knee replacement for osteoarthritis, or after femoral neck fracture in patients without symptoms of osteoarthritis. Moreover, the layers of residual cartilage from chondral posttraumatic defects obtained during preoperative arthroscopy and of newly formed cartilage after autologous-chondrocyte transplantation (Hyalograft C) obtained during second-look arthroscopy were also examined by immunohistochemistry and RT PCR. Our study showed that a significant percentage of articular chondrocytes express alpha-smooth muscle actin in healthy, diseased, and regenerated articular cartilage. Alpha-actin positive chondrocytes (18%) were observed predominantly in the upper zone of normal articular cartilage. By contrast, only approximately 10% of cartilage cells in the deep region stained for this contractile actin isoform. Actin-positive chondrocytes (myochondrocytes) are formed predominantly in response to injury to the osteoarthrotic cartilage, at sites of defective healing, and in newly formed cartilage after autologous chondrocyte transplantation. Fibrocartilage is present in some of these conditions, and it is known that this tissue contains chondrocytes with actin. The presence of myochondrocytes in the surface layer of normal articular cartilage indicates that this region probably plays an important role in maintaining cartilage integrity. Myochondrocytes may utilize the contractile actin isoform in manipulating the extracellular matrix of articular cartilage. It is also possible that actin-containing chondrocytes have a higher potential for regeneration in contrast to chondrocytes that do not contain this contractile material in their cytoplasm.

Secondary fracture prevention in hip fracture patients requires cooperation from general practitioners.

Despite individual recommendations on osteoporosis management in patients after hip fracture surgery, addressed by orthopedic surgeons to Czech general practitioners, the patients remained undiagnosed and untreated because of provider-level barriers to post-fracture secondary prevention. PURPOSE: The goal of the study was to assess whether an individual recommendation on osteoporosis treatment addressed to a hip fracture patient's GP would lead to better osteoporosis management. METHODS: Two groups of patients who suffered hip fractures and were treated at the Orthopedic Department were evaluated. In 111 patients, general recommendations on osteoporosis treatment and fracture prevention were provided in a discharge report addressed to the GP. In the second group, 96 patients were provided individually with a detailed written set of recommendations on osteoporosis examination, treatment, and fracture prevention, which was also provided in the discharge report. A questionnaire to assess the provided care was mailed to the patients 5.3 ± 1.2 months of discharge. Those patients who did not return the questionnaires were contacted by phone. RESULTS: The questionnaires were received from 44% and 49% of patients from the general and detailed recommendation groups, respectively. Along with the phone call, we were able to contact 78 (70.3%) and 68 (70.8%) patients from the general and detailed recommendation groups, respectively. GPs secured osteoporosis evaluation in 14.6% of the patients. Calcium supplementation and vitamin D supplementation were newly provided in 42.7 and 36.4% of the patients, respectively. Anti-resorptive therapy was newly provided in 8.3% of the patients. No significant differences between the groups were observed in osteoporosis evaluation, calcium and vitamin D supplementation, and anti-osteoporosis treatments. Out of 207 patients, further examination or treatment was requested by 45 patients (21.7%); 75 patients (36.2%) declared no interest in further care. CONCLUSION: Recommendations on osteoporosis management addressed to Czech GPs after surgical fracture management had little effect on treatment. As the anti-osteoporotic preparations can only be prescribed by specialists, the availability of necessary examinations and treatment is limited by the motivation of GPs. Consequently, the implementation of Fracture Liaison Services to help close the care gap may be limited in the absence of participation by Czech GPs.

Focal osteoporosis defects play a key role in hip fracture.

BACKGROUND: Hip fractures are mainly caused by accidental falls and trips, which magnify forces in well-defined areas of the proximal femur. Unfortunately, the same areas are at risk of rapid bone loss with ageing, since they are relatively stress-shielded during walking and sitting. Focal osteoporosis in those areas may contribute to fracture, and targeted 3D measurements might enhance hip fracture prediction. In the FEMCO case-control clinical study, Cortical Bone Mapping (CBM) was applied to clinical computed tomography (CT) scans to define 3D cortical and trabecular bone defects in patients with acute hip fracture compared to controls. Direct measurements of trabecular bone volume were then made in biopsies of target regions removed at operation. METHODS: The sample consisted of CT scans from 313 female and 40 male volunteers (158 with proximal femoral fracture, 145 age-matched controls and 50 fallers without hip fracture). Detailed Cortical Bone Maps (c.5580 measurement points on the unfractured hip) were created before registering each hip to an average femur shape to facilitate statistical parametric mapping (SPM). Areas where cortical and trabecular bone differed from controls were visualised in 3D for location, magnitude and statistical significance. Measures from the novel regions created by the SPM process were then tested for their ability to classify fracture versus control by comparison with traditional CT measures of areal Bone Mineral Density (aBMD). In women we used the surgical classification of fracture location ('femoral neck' or 'trochanteric') to discover whether focal osteoporosis was specific to fracture type. To explore whether the focal areas were osteoporotic by histological criteria, we used micro CT to measure trabecular bone parameters in targeted biopsies taken from the femoral heads of 14 cases. RESULTS: Hip fracture patients had distinct patterns of focal osteoporosis that determined fracture type, and CBM measures classified fracture type better than aBMD parameters. CBM measures however improved only minimally on aBMD for predicting any hip fracture and depended on the inclusion of trabecular bone measures alongside cortical regions. Focal osteoporosis was confirmed on biopsy as reduced sub-cortical trabecular bone volume. CONCLUSION: Using 3D imaging methods and targeted bone biopsy, we discovered focal osteoporosis affecting trabecular and cortical bone of the proximal femur, among men and women with hip fracture.

Cortical thickness mapping to identify focal osteoporosis in patients with hip fracture.

BACKGROUND: Individuals with osteoporosis are predisposed to hip fracture during trips, stumbles or falls, but half of all hip fractures occur in those without generalised osteoporosis. By analysing ordinary clinical CT scans using a novel cortical thickness mapping technique, we discovered patches of markedly thinner bone at fracture-prone regions in the femurs of women with acute hip fracture compared with controls. METHODS: We analysed CT scans from 75 female volunteers with acute fracture and 75 age- and sex-matched controls. We classified the fracture location as femoral neck or trochanteric before creating bone thickness maps of the outer 'cortical' shell of the intact contra-lateral hip. After registration of each bone to an average femur shape and statistical parametric mapping, we were able to visualise and quantify statistically significant foci of thinner cortical bone associated with each fracture type, assuming good symmetry of bone structure between the intact and fractured hip. The technique allowed us to pinpoint systematic differences and display the results on a 3D average femur shape model. FINDINGS: The cortex was generally thinner in femoral neck fracture cases than controls. More striking were several discrete patches of statistically significant thinner bone of up to 30%, which coincided with common sites of fracture initiation (femoral neck or trochanteric). INTERPRETATION: Femoral neck fracture patients had a thumbnail-sized patch of focal osteoporosis at the upper head-neck junction. This region coincided with a weak part of the femur, prone to both spontaneous 'tensile' fractures of the femoral neck, and as a site of crack initiation when falling sideways. Current hip fracture prevention strategies are based on case finding: they involve clinical risk factor estimation to determine the need for single-plane bone density measurement within a standard region of interest (ROI) of the femoral neck. The precise sites of focal osteoporosis that we have identified are overlooked by current 2D bone densitometry methods.