Sodium alendronate: proposal and reliability of indicators

Abstract The present study proposes and evaluates the test-retest reliability of indicators of the correct use of sodium alendronate in elderly patients. This is a test-retest reliability study for use of sodium alendronate. Six questions to evaluate the correct use of this medicine were elaborated after analysis of information in the literature. Data collection was performed through questionnaires in face-to-face in-home interviews by previously trained interviewers. The participants were initially interviewed (test) when they agreed to participate in the study, and secondly (retest), after a period of 7 to 14 days from the first interview. The reliability of the questions was evaluated by means of the agreement percentage and the Kappa coefficient. Fifty-seven pairs (test-retest) were obtained. The mean age was 69.3 (SD = 6.9) years, the majority (92.5%) completed elementary education, and declared themselves white (50.9%). All the questions presented high concordance ranging from 79.0% to 98.3%. The Kappa values ranged from 0.1 (low) to 0.83 (very good). The agreement percentage and the Kappa values suggest adequate reliability of the proposed questions. We suggest that they can be used as a simple and quick way to evaluate the quality of sodium alendronate use among the elderly.

Fabrication of Membrane Sensitive Electrodes for the Validated Electrochemical Quantification of Anti-Osteoporotic Drug Residues in Pharmaceutical Industrial Wastewater.

Accurate and precise application of ion-selective electrodes (ISEs) in the quantification of environmental pollutants is a strenuous task. In this work, the electrochemical response of alendronate sodium trihydrate (ALN) was evaluated by the fabrication of two sensitive and delicate membrane electrodes, viz. polyvinyl chloride (PVC) and glassy carbon (GC) electrodes. A linear response was obtained at concentrations from 1 × 10-5 to 1 × 10-2 M for both electrodes. A Nernstian slope of 29 mV/decade over a pH range of 8-11 for the PVC and GC membrane electrodes was obtained. All assay settings were carefully adjusted to obtain the best electrochemical response. The proposed technique was effectively applied for the quantification of ALN in pure form and wastewater samples, acquired from manufacturing industries. The proposed electrodes were effectively used for the determination of ALN in real wastewater samples without any prior treatment. The current findings guarantee the applicability of the fabricated ISEs for the environmental monitoring of ALN.

Quantification of the bisphosphonate alendronate using capillary electrophoresis mass spectrometry with dynamic pH barrage junction focusing.

A quantitative method was developed for the direct identity confirmation and quantification of alendronate using CE-MS combined with a pH-assisted focusing technique, dynamic pH barrage junction focusing. A pH-induced variation in electrophoretic mobility led to online focusing of alendronate at the sample/pH barrage boundary, significantly improving the detection sensitivity. In addition, the use of a flow-through microvial CE electrospray interface and the multiple reaction monitoring mode of MS further improved the specificity and quantification capability of this technology. This quantitative method presented a wide linear dynamic range over 8-2000 ng/mL and an LOD of 2 ng/mL. A 460-fold improvement in sensitivity was obtained when pH barrage junction focusing was applied during the CE process, in comparison to when normal CE was conducted without online sample stacking. The superior detection sensitivity over previously reported methods enables direct analysis of bisphosphonate compounds, eliminating tedious pre-column sample enrichment and derivatization. Validation of alendronate content in a commercial drug tablet further proved the reliability and power of this method. This simple method with no sample derivatization, superior sensitivity, and short run time (<8 min) is a promising alternative for accurate quantification of alendronate and other types of bisphosphonate compounds in both drug formulations and plasma samples.

Fracturas atípicas de fémur asociadas al uso de bifosfonatos / Bisphosphonate associated atypical femur fractures

Resumen Los bifosfonatos son medicamentos ampliamente conocidos por su efecto antagonista de la resorción ósea y la consecuente reducción del riesgo de fracturas en los pacientes con osteoporosis. La literatura actual provee evidencia en términos de datos clínicos y experimentales que asocian el uso prolongado de estos medicamentos con un aumento en el riesgo de fracturas atípicas de fémur. Para establecer si esta asociación es clínicamente relevante, se requiere realizar estudios posteriores que incluyan la relación entre otros factores que podrían influir en la aparición de este tipo de fracturas como lo es la propia enfermedad osteoporótica, el tipo de bifosfonato utilizado, el mecanismo lesional que originó la fractura, medicamentos concomitantes y patologías asociadas.

Abstract Bisphosphonates are medications that are widely known for their antagonizing effect on bone resorption and their consequent reduction in the risk of fractures in patients with osteoporosis. Current literature provides evidence in terms of experimental and clinical data associating prolonged use of these drugs with an increase in the risk of atypical femur fractures. To establish if this association is clinically relevant, there lies a need for further studies that take into account other factors that might influence the occurrence of these type of fractures, like the osteoporotic disease itself, age, intake of other drugs and associated systemic illnesses.

FITC-Labeled Alendronate as an In Vivo Bone pH Sensor.

pH is a critical indicator of bone physiological function and disease status; however, noninvasive and real-time sensing of bone pH in vivo has been a challenge. Here, we synthesized a bone pH sensor by labeling alendronate with the H+-sensitive dye fluorescein isothiocyanate (Aln-FITC). Aln-FITC showed selective affinity for hydroxyapatite (HAp) rather than other calcium materials. An in vivo biodistribution study showed that Aln-FITC can be rapidly and specifically delivered to rat bones after caudal vein injection, and the fluorescence lasted for at least 12 h. The fluorescence intensity of Aln-FITC binding to HAp linearly decreased when the pH changed from 6 to 12. This finding was further confirmed on bone blocks and perfused bone when the pH changed from 6.8 to 7.4, indicating unique pH-responsive characteristics in the bone microenvironment. Aln-FITC was then preliminarily applied to evaluate the changes in bone pH in a nude mouse acidosis model. Our results demonstrated that Aln-FITC might have the potential for minimally invasive and real-time in vivo bone pH sensing in preclinical studies of bone healing, metabolism, and cancer mechanisms.

A simple innovative spectrofluorometric method for the determination of alendronate in bulk and in pharmaceutical tablets.

Sodium alendronate is the first in a pharmacological class known as bisphosphonates, used for treatment of various bone diseases. Assay of bisphosphonates by a spectroscopic technique is very challenging due to the fact that they lack chromophores and none of them are fluorescent. In this work, a simple method is presented for determination of alendronate in bulk and in pharmaceutical tablets using spectrofluorometry by exploiting the ability of alendronate to displace salicylate from the iron(III)-salicylate chelate, forming a non-fluorescent colorless iron(III)-alendronate complex. The liberated salicylate is fluorescent and is equivalent to the mount of alendronate added. The response was linear over the concentration range 20-90 µM and the proposed method was validated according to the guidelines of the International Conference on Harmonization. The correlation coefficient was found to be 0.995 and the limit of detection was 7.5 µM. The method was successfully applied for determination of alendronate in the commercially available Osteonate® tablets. The average percent recovery ± percent relative standard deviation was found to be 102.118 ± 2.033 which is congruent with the label claim of the dosage form. The results were also compared to a reported method using t-test and F-test at 95% confidence level; no significant differences were observed. The presented method is simple, fast, easy, cost-effective and suitable for routine pharmaceutical analysis.

Hantzsch pre-column derivatization for simultaneous determination of alendronate sodium and its pharmacopoeial related impurity: Comparative study with synchronous fluorometry using fluorescamine.

High performance liquid chromatographic (HPLC) method with a pre-column derivatization based on Hantzsch condensation reaction was applied for simultaneous determination of alendronate sodium (ALN) and its main related impurity, 4-Aminobutanoic acid (ABA) at its pharmacopeial limit. The separation of colored condensation products of ALN and ABA were achieved on Agilent Zobrax Eclipse SB-C18 analytical column (250 × 4.6 mm, 5 µm) using a mobile phase composed of acetonitrile-0.1 M acetate buffer, pH 5.0 (15:85, v/v). The flow rate was 1 mL min-1. The detection was carried out at 340 nm using photo-diode array detector. Peak areas were used for the linear regression line in the range of 10-500 and 0.2-40 µg mL-1 for ALN and ABA, respectively. Different conditions for the optimization of the derivatization reactions as well as for the HPLC measurement were studied. The proposed method was validated for linearity, precision, accuracy, specificity and robustness. This method was used to check the purity of ALN in the presence of ABA (related impurity) at the pharmacopeial limit (0.5%). For comparison purpose, another method was proposed which involves synchronous fluorescence measurement after ALN reaction with fluorescamine. In this method, the third derivative synchronous spectra were estimated as peak to peak measurement from 339 to 370 nm for ALN determination with LOD and LOQ of 24 and 73 ng mL-1, respectively, showing very high sensitivity. Both methods have been applied for determination of the alendronate sodium (ALN) in bulk and pharmaceutical preparations without interference of additives in tablets or oral solution.

Development and validation of a novel sensitive UV-direct capillary electrophoresis method for quantification of alendronate in release studies from biomaterials.

A simple, highly sensitive, and robust CE method applied to the determination of alendronate (ALN) was developed from matrices for tissue engineering, characterized by being highly complex systems. The novel method was based on the ALN derivatization with o-phthalaldehyde and 2-mercaptoethanol for direct ultraviolet detection at 254 nm. The BGE consisted of 20 mM sodium borate buffer at pH 10, and the electrophoretic parameters were optimized.The method was validated in terms of specificity, linearity, LOD, LOQ, precision, accuracy, and robustness. The LOD and LOQ obtained were 0.8 and 2.7 µg/mL, respectively. In addition, the method offers higher sensitivity and specificity compared to other CE and HPLC methods using UV-detectors, as well as low cost and simplicity that allowed the rapid and simple quantitation of ALN from bone regeneration matrices.

Efectividad del alendronato más calcio y vitamina D, comparado con calcio y vitamina D para la prevención de la fractura de cadera / Hip fractures prevention: Effectiveness with alendronate plus calcium+vitamin D compared with calcium +vitamin (control group

Resumen:Objetivo:establecer la efectividad del alendronato, comparado con un grupo control, para prevenir la fractura de cadera y perfilar la mortalidad a corto plazo.Métodos:estudio observacional, analítico, con todos los pacientes atendidos en la Seguridad Social con tratamiento con alendronato, calcio y vitamina D (grupo A), o con calcio y vitamina D (grupo control, C), que recibieron tratamiento continuo por 1 año como mínimo, y lo mantuvieron durante el periodo de observación y seguimiento, 3 años o hasta que ocurrió el evento de fractura, según el registro institucional por diagnóstico y la condición de egreso (vivo o fallecido).Resultados:en total se incluyó una muestra de 10395 pacientes que cumplieron con el tratamiento continuo previo y durante el seguimiento a 3 años; n= 5 570 (53,58%) expuestos al alendronato 70 mg semanal junto con calcio y vitamina D y como control, n= 4 825 (46,42%) que recibieron calcio y vitamina D. Durante el seguimiento a 3 años de ambos grupos, se registró un total de 108 fracturas de cadera; el evento ocurrió en el 1,08% de los pacientes que recibieron alendronato y en el 0,99% del control. La efectividad del tratamiento con alendronato (junto con calcio y vitamina D) para prevenir la fractura de cadera, se estableció en el 98,92%, similar a lo registrado para el grupo control (99,01%). La mortalidad aguda por fractura de cadera registrada en un tiempo máximo de 35 días de hospitalización (Cuadro 2), en el grupo alendronato alcanzó el 11,66% y todas eran mujeres. En el grupo control, la mortalidad aguda llegó al 22,91% y un 72,72% eran mujeres.Conclusiones:no hubo diferencias significativas en los grupos evaluados en número de fracturas ni mortalidad. Los adultos mayores resultaron más vulnerables para sufrir este evento y para un desenlace fatal a corto plazo.

Abstract:Objective:To establish the effectiveness of alendronate, compared to a control group, in preventing hip fracture and outline the short-term mortality.Methods:Observational, analytical study, with all patients treated at the Social Security, for at least 1 continuous year, with alendronate, calcium and vitamin D (group A) and control group (C) with calcium and vitamin D, follow up by three years or until the event occurred (hip fracture) according to the institutional record for diagnosis and discharge status (alive or deceased). Subgroup analyzes> 65 years.Results:The total sample included 10395 patients that followed the pretreatment and the 3-year follow up. Group A n = 5.570 (53.58%) exposed to weekly 70mg alendronate with calcium and vitamin D, 95% female, mean age 69 years, median treatment period before event 749 days. Control group C n = 4.825, that received calcium and vitamin D, 89% female, 66 years old and 775 days of treatment, respectively. During the studied period (three years) 108 fractures were registered, 60 in group A (1.08%) and 48 in group C (0.99%). The effectiveness of the treatment with alendronate (with calcium and vitamin D) to prevent hip fracture was established in the 98.92%, similar to that registered for the control group (99.01). The acute mortality for hip fracture, registered in a maximum time of 35 days of hospitalization (table 2), in the alendronate group reached the 11.66% and were all women. In the control group acute mortality reached 22.91% and 72.72% were women.Conclusions:Alendronate showed similar effectiveness to control to prevent hip fractures. Older adults were more vulnerable to suffer this event and a short-term fatal outcome.

Alendronate sodium.

This chapter is a review on physical and chemical properties, methods of preparation, analysis, as well as pharmacodynamics and pharmacokinetics of Alendronate sodium (4-amino-1-hydroxybutane-1,1-diphosphonic acid sodium salt), a bone metabolism regulator, indicated for the treatment of excessive bone resorption and osteoporosis.

Analysis of alendronate in human urine and plasma by magnetic solid-phase extraction and capillary electrophoresis with fluorescence detection.

A simple, rapid and sensitive CE-fluorescence (FL) detection method for the analysis of alendronate (ALEN), a bisphosphonate drug, has been developed. Using a buffer solution of 20 mM sodium phosphate (pH 10.0) and a voltage of 24 kV, separation of ALEN in a 55-cm length (35-cm effective length) capillary was achieved in 5 min. FL detection of ALEN was performed via pre-column derivatization with 2,3-naphthalene dicarbox-yaldehyde (NDA). Linear correlation (r=0.9981, n=6) between FL intensity and analyte concentration was obtained in the range of 7-200 ng/mL ALEN. The developed CE-FL method was applied to the analysis of ALEN in human urine and plasma samples. In order to eliminate the interfering matrix components, SPE using magnetic Fe(3) O(4) @Al(2) O(3) nanoparticles as solid sorbents was employed to clean the biological fluids before CE-FL analysis. The linear ranges of ALEN in urine and plasma were 5-100 ng/mL (r = 0.9982, n = 7) and 5-70 ng/mL (r = 0.9954, n = 7), respectively. The LOD and LOQ in both urine and plasma samples were 1.5 and 5 ng/mL ALEN, respectively. Total analysis time including sample pre-treatment and CE separation was less than 1.5 h.

Clinical efficacy of 1% alendronate gel as a local drug delivery system in the treatment of chronic periodontitis: a randomized, controlled clinical trial.

BACKGROUND: Alendronate (ALN), an aminobisphosphonate, is known to inhibit osteoclastic bone resorption and was proposed to have osteostimulative properties in vivo and in vitro as shown by an increase in matrix formation. The present study aims to explore the efficacy of a 1% ALN gel compared to a placebo gel as a local drug delivery system in adjunct to scaling and root planing (SRP) for the treatment of intrabony defects in patients with chronic periodontitis. METHODS: A total of 66 intrabony defects were treated with a 1% ALN or placebo gel. The ALN gel was prepared by adding ALN to a polyacrylic acid-distilled water mixture. Clinical parameters (modified sulcus bleeding index, plaque index, probing depth [PD], and clinical attachment level [CAL]) were recorded at baseline and 2 and 6 months, and radiographic parameters at baseline and 6 months. The defect fill at baseline and 6 months was calculated on standardized radiographs by using image-analysis software. RESULTS: The mean PD reduction and CAL gain were greater in the ALN group than in the placebo group at 2 and 6 months. Furthermore, a significantly greater mean percentage of bone fill was found in the ALN group (40.4% ± 11.71%) than in the placebo group (2.5% ± 1.02%). CONCLUSIONS: Results of the present study shows that the local delivery of 1% ALN into the periodontal pocket stimulated a significant increase in PD reduction, CAL gain, and improved bone fill compared to a placebo gel as an adjunct to SRP. These results can provide a new direction in the field of periodontal healing.

Fluorescence imaging of osteoclasts using confocal microscopy.

In order to understand osteoclast cell biology, it is necessary to culture these cells on a physiological -substrate that they can resorb in vitro, such as bone or dentine. However, this creates problems for analysis by fluorescence microscopy, due to the depth of the sample under investigation. By virtue of its optical sectioning capabilities, confocal microscopy is ideal for analysis of such samples, enabling precise intracellular localisation of proteins in resorbing osteoclasts to be determined. Moreover, by taking a series of images in the axial dimension, it is possible to create axial section views and to reconstruct 3D images of the osteoclasts, enabling the spatial organisation of the structures of interest to be more easily discerned.

Fluorimetric quantification of clodronate and alendronate in aqueous samples and in serum.

The bisphosphonates clodronate and alendronate are drugs in the therapy of osteoporosis or Paget's disease. They are highly hydrophilic and therefore of low oral bioavailability. Determination methods for bisphosphonates are often laborious and expensive equipment is needed. The presented quantification method based on kinetic measurement of the fluorescence decrease of an Al(3+)-morin complex can be used to determine the bisphosphonate content in aqueous and plasma samples. The intra- and inter-assay accuracies were found to be within 98.8% and 102.3% of the target samples for clodronate and within 97.2% and 105.0% of the target samples for alendronate. The LOQ was defined as 15.6 ng/ml for clodronate and 62.5 ng/ml for alendronate. In serum samples, intra- and inter-assay accuracy was found to be within 99.0% and 101.6% of the target samples for clodronate and within 97.8% and 102.6% of the target samples for alendronate. In serum samples, the LOQ was defined as 1.55 mg/ml for clodronate and 0.39 mg/ml for alendronate. Though less sensitive in serum, the presented method could support research on the development of drug delivery systems in vitro and in vivo for the investigated and other structurally related bisphosphonates.

Demineralization removes residual alendronate in allograft bone procured from donors with a history of bisphosphonate use.

BACKGROUND: Bisphosphonate-associated osteonecrosis (BON) of the jaw is a growing concern in the dental community, but the possible presence of residual bisphosphonates in demineralized allograft bone from bisphosphonate-using tissue donors and the clinical implications of using such bone are unclear. The objectives of this study are to determine whether alendronate remained in demineralized bone matrix (DBM) procured from donors with a documented history of oral bisphosphonate use and to examine whether the demineralization process removes alendronate from allograft bone. METHODS: A gas chromatography?mass spectrometry method was developed and validated to quantify residual alendronate in allograft bone. Alendronate levels in DBM procured from tissue donors with a history of oral bisphosphonate use were compared to alendronate levels in DBM procured from donors without a history of bisphosphonate use. In addition, mineralized and demineralized bone was soaked in alendronate at concentrations of 0.002, 2.0, and 2,000 ng/mg bone and analyzed to examine the effect of the demineralization process. RESULTS: Residual alendronate was not detected in the DBM from either group, nor was it detected in any of the DBM samples soaked in alendronate solutions. Soaked mineralized bone contained measureable alendronate, but the substance was removed by demineralization. CONCLUSIONS: The demineralization process effectively removed residual alendronate from allograft bone. These results may relieve anxieties regarding the use of DBM in dental patients because it is unlikely to trigger BON of the jaw.

Rapid analysis of alkylphosphonate drugs by capillary zone electrophoresis using indirect ultraviolet detection.

A rapid capillary electrophoretic method for the analysis of three alkylphosphonate drugs (i.e. fosfomycin disodium (FOS), clodronate disodium (CLO) and alendronate sodium (ALN)) was developed by using multiple probe BGE and indirect UV detection. BGE containing 30 mM benzoic acid, 5 mM salicylic acid and 0.5 mM CTAB (pH 3.8), temperature of 30 degrees C, applied voltage of -30 kV and detection at 220 nm provided baseline separation of all analytes (resolution (R)>2.2) in 3.2 min. EOF reversal by addition of CTAB and negative voltage polarity leading to the co-EOF flow and short analysis time. Two probe BGE greatly improved peak symmetry. The method showed good linearity (r(2)>0.999 in ranges of 20-1000 microg/mL for FOS, 100-1000 microg/mL for CLO and 100-750 microg/mL for ALN) repeatablitiy (RSD<2.15%), recovery (99.3-101.1%) and sensitivity (LOD<50 microg/mL). Freshly prepared BGE and sample solutions are essential for the method precision and accuracy. This new method can be utilized for routine analysis of FOS, CLO and ALN in dosage forms because of its efficiency, reliability, speed and simplicity.

Considerações sobre a determinação quantitativa de alendronato de sódio: titulometria x cromatografia / Observations on the quantitative determination of alendronate sodium: titrimetry vs. chromatography

O alendronato de sódio é um composto aminodifosfonado capaz de se fixar à matriz óssea e inibir a reabsorção mediada por osteoclastos. A escassez de metodologias oficiais para a determinação quantitativa deste fármaco levou ao desenvolvimento de diversos métodos, os quais empregam, em sua maioria, a cromatografia líquida de alta eficiência (CLAE), com a derivatização do fármaco para poder empregar detectores de ultravioleta. Também há relatos sobre metodologias mais simples para a análise do alendronato, utilizando titulometria ou análise espectrofotométrica. Neste trabalho foi avaliado o emprego da titulometria de neutralização na determinação quantitativa do alendronato de sódio em três lotes de matéria-prima, utilizando NaOH 0,1 M como titulante. Os resultados obtidos na titulometria foram comparados aos encontrados em método cromatográfico de referência (CLAE com derivatização por 9-fluorenilmetilcloroformato ou FMOC), descrito na Farmacopéia Americana (United States Pharmacopeia), os quais apresentaram valores estatisticamente diferentes. Ensaios para a caracterização das amostras também foram realizados e foi observado comportamento distinto das 3 matérias-primas em relação à substância de referência (padrão secundário). O método titulométrico apresentou adequada precisão, mas não mostrou especificidade para a determinação das matérias-primas, embora possa ser validado para determinação do fármaco em produto acabado.

Alendronate sodium is an aminobisphosphonate compound that can bind to the bone matrix and inhibit its osteoclast-mediated resorption. The lack of official monographs on the quantitative analysis of this drug has led to the proposal of a number of different methods for its determination, most of which employ high performance liquid chromatography (HPLC), performed after derivatization of the drug to enable ultraviolet detection. Simpler methodologies based on titrimetry and spectrophotometry have also been described. In this paper, the results obtained by acid-base titration of three batches of bulk alendronate, with 0.1 M sodium hydroxide as titrant, were compared with those achieved by a chromatographic reference method (HPLC of an FMOC derivative of the drug) published in the United States Pharmacopeia. The two methods gave statistically different results for the analysis of the three samples. Also, physical and chemical characterization of these samples showed differences between them and the reference substance (brand-name drug). The acid-base titrimetry was precise but not specific for determination of the bulk drug. However, it may be employed in the quality control of alendronate sodium dosage forms, since the excipients do not interfere with the analysis.

Implante de biomateriais e a consolidação óssea em cadelas submetidas à ovariossalpingo-histerectomia / Influence of biomaterials on the bony consolidation in spayed female dogs

Avaliou-se a hidroxiapatita com alandronato e hidroxiapatita com colágeno na aceleração da consolidação óssea do rádio de cadelas adultas submetidas à ovariossalpingo-histerectomia (OSH). Utilizaram-se 14 cadelas adultas, distribuídas aleatoriamente em dois grupos: grupo-controle e grupo OSH (submetidas à OSH). Quatro meses após a OSH, as cadelas dos dois grupos foram submetidas à cirurgia para produção de uma falha óssea de 4mm de diâmetro nos terços distal e proximal do rádio. No terço distal do membro direito, foi utilizada a hidroxiapatita com alandronato e, no membro esquerdo, a hidroxiapatita com colágeno; no terço proximal, não se utilizou nenhum biomaterial. Houve retardo na consolidação das falhas ósseas nas cadelas submetidas à OSH comparadas com as não submetidas. A hidroxiapatita com alandronato acelerou o processo de reparação e, em todos os animais dos dois grupos, a densidade óssea foi significativamente maior no terço distal onde foi implantada. Os dois biomateriais apresentaram biocompatibilidade, constatada pela ausência de reação inflamatória ou outra reação indesejável.

The hydroxyapatite with alendronate and hydroxyapatite with collagen were evaluated in the acceleration of the bony consolidation of adult spayed bitch radius. For that, 14 adult bitches were distributed in two groups (control and spayed). Four months after ovariohysterectomy, the groups were submitted to the surgery for production of a 4mm diameter bony flaw in the distal and proximal third regions of the radius. In the distal region of the right thoracic limb, hydroxyapatite with alendronate was used. In the distal region of the left thoracic limb, hydroxyapatite with collagen was used. Any biomaterial was used in proximal part of the limb. There was a retard in bony flaws consolidation in the spayed bitches. Hydroxyapatite with alendronate showed better result, since the place it was implanted considerably increased the bony formation. Both biomaterials presented biocompatibility, verified by the absence of inflammatory reaction or other undesirable reaction.

In vitro determination of the release of alendronic acid from alendronate tablets of different brands during deglutition.

Alendronic acid, a frequently applied compound for the treatment of different forms of diseases of bone metabolism, is a strong acid with a high solubility in water. In connection with the oral administration this exhibits a potential health risk for the upper gastrointestinal tract. The in vitro release of tablets containing alendronic acid of different brands (Stada, ratiopharm, interpharm, Fosamax) was determined by dissolution tests for the time period required for oral intake. The effect of rotation speed, temperature, and solvent volume on the release rate of alendronic acid was determined for the used dissolution apparatus. Analysis of alendronic acid was performed by a validated HPLC method. The highest rate of release was found for the original brand. The dissolution rate of the generic formulations was significantly lower in the early stage of dissolution. Over the complete range of dissolution, more than 85% of the claimed amount was dissolved within 4 min. Dissolution profiles were compared by calculation of the similarity factor f(2) showing equal products with the exception of one generic product, whose dissolution rate was lower.

Electrospray tandem mass spectrometry of alendronate analogues: fingerprints for characterization of new potential prodrugs.

1-hydroxymethylene-1,1-bisphosphonic acids (HMBPs) are important drugs for the treatment of a variety of bone diseases. Since these compounds have no chromophore, their detection is challenging and mass spectrometry (MS) appears to be an appropriate sensitive tool. Our work deals with the analysis by electrospray ionization tandem mass spectrometry (ESI-MSn) of the well-known nitrogen-containing HMBP alendronate and of three analogues, considered as potential prodrugs. These four molecules share a common structure with different protecting groups on the phosphonic acid and on the amine functions. We describe the dissociation mechanisms of nitrogen-containing HMBPs in positive ion mode and we compare, in negative ion mode, our results with literature data. In both modes, the dissociations are essentially losses of ROH, and of phosphorus-containing species (HPO2, ROP(OH)2 and ROPO(OH)2), where R=H, C6H5, or CH3OC6H5. These fingerprints will be of great value for differentiating alendronate from its potential prodrugs in complex biological mixtures.