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.

COMPARATIVE BIOAVAILABILITY ANALYSIS OF ORAL ALENDRONATE SODIUM FORMULATIONS IN PAKISTAN.

Alendronate sodium, a bisphosphonate drug, it is used to treat osteoporosis and other bone diseases. The present study was designed to conduct comparative bioavailability analysis of oral formulations of aledronate sodium through an open-label, randomized, 2-sequence, 2-period crossover study. Healthy adult male Pakistani volunteers received a single 70 mg dose of the test or reference formulation of alendronate sodium followed by a 7 day washout period. Plasma drug concentrations were determined using a validated HPLC post column fluorescence derivatization method. AUC(01,) AUC(0-8,) C(max). and T(max) were determined by non-compartmental analysis and were found within the permitted range of 80% to 125% set by the US Food and Drug Administration (FDA). Results show that both in vitio and in vivo assays of all test brands were within the spec- ification of the US Pharmacopoeial limits and were statistically bioequivalent. No adverse events were reported in this study.

The Effect of Alendronate Loaded Biphasic Calcium Phosphate Scaffolds on Bone Regeneration in a Rat Tibial Defect Model.

This study investigated the effect of alendronate (Aln) released from biphasic calcium phosphate (BCP) scaffolds. We evaluated the in vitro osteogenic differentiation of Aln/BCP scaffolds using MG-63 cells and the in vivo bone regenerative capability of Aln/BCP scaffolds using a rat tibial defect model with radiography, micro-computed tomography (CT), and histological examination. In vitro studies included the surface morphology of BCP and Aln-loaded BCP scaffolds visualized using field-emission scanning electron microscope, release kinetics of Aln from BCP scaffolds, alkaline phosphatase (ALP) activity, calcium deposition, and gene expression. The in vitro studies showed that sustained release of Aln from the BCP scaffolds consisted of porous microstructures, and revealed that MG-63 cells cultured on Aln-loaded BCP scaffolds showed significantly increased ALP activity, calcium deposition, and gene expression compared to cells cultured on BCP scaffolds. The in vivo studies using radiograph and histology examination revealed abundant callus formation and bone maturation at the site in the Aln/BCP groups compared to the control group. However, solid bony bridge formation was not observed at plain radiographs until 8 weeks. Micro-CT analysis revealed that bone mineral density and bone formation volume were increased over time in an Aln concentration-dependent manner. These results suggested that Aln/BCP scaffolds have the potential for controlling the release of Aln and enhance bone formation and mineralization.

Anti-reabsorptive agents in women with osteoporosis: determining statistical equivalence according to evidence-based methods.

BACKGROUND: In the present study, we undertook an equivalence analysis on the effectiveness of the main anti-reabsorptive agents indicated for women with osteoporosis. METHODS: Our methodology was a combination of meta-analysis (both pair-wise meta-analysis and network meta-analysis) and equivalence testing. The end-point was the incidence on new vertebral fractures. The anti-reabsorptive agents examined included alendronate, zoledronate, ibandronate, risedronate, and denosumab. RESULTS: Our analysis involved nine randomized trials. Ten head-to-head indirect comparisons were examined through network meta-analysis and the respective values of RR were estimated. The 95 % confidence intervals for RR remained within the interval of a relative ±40 % variation for all comparisons that involved alendronate, risedronate, ibandronate, and denosumab. In contrast, the comparisons involving zoledronate satisfied a post hoc margin up to ±67 %. CONCLUSION: Our results confirm that most of these anti-reabsorptive drugs (namely, alendronate, risedronate, ibandronate, and denosumab) are equivalent according to reasonable equivalence margins.

Renal drug dosing recommendations: evaluation of product information for brands of the same drug.

OBJECTIVES: To review the product information (PI) for various brands of the same generic drugs and investigate the extent to which information is currently available on dosing in renal impairment and the concordance between the dosing recommendations for the same generic drug. METHOD: The Monthly Index of Medical Specialities (MIMS) was examined for 28 generic drugs recommended to be used with caution in renal impairment. For each generic drug all available brands listed as having solid oral dosage form were recorded. For each identified brand, the current PI was consulted and data referring to renal impairment was collated. The dissimilarity between these PI regarding the renal dosage recommendation was determined. RESULTS: There was generally a lack of detailed information in the PI on the use of drugs in patients with renal impairment. The majority of PI documents (88 of 155 PI; 57%) provided quantitative dosage recommendations, but this was often not detailed enough to help users to make an informed decision. For 37 PI documents (24%), an altered dosage regimen was proposed without a quantifiable measure of renal function reported in the dose recommendation. The renal function severity category terms used and the associated quantitative values were also not consistent. It was observed that the recommendations varied among different brands of hydromorphone, morphine, oxycodone, tramadol, metformin and topiramate. CONCLUSION: The reporting of renal function quantification methods, and associated dosage recommendations, in PI requires standardisation to ensure optimal drug dosing. Regularly updating of PI is also necessary.

A simple pharmacokinetic model of alendronate developed using plasma concentration and urine excretion data from healthy men.

The study of pharmacokinetics of alendronate has been hampered by difficulties in accurately and reproducibly determining their concentrations in serum and urine. Thus, pharmacokinetic characteristics of alendronate have been described in many reports based on urinary excretion data; and plasma pharmacokinetics and the simultaneous pharmacokinetic models of alendronate in plasma and urine are not available. The aims of this study were to measure alendronate concentration in plasma and excretion in urine concurrently and to develop compartmental pharmacokinetic model using urine data. In open-label, single-dose pharmacokinetic study, 10 healthy male volunteers received oral dose of alendronate (70 mg tablet). Blood and urine alendronate concentrations were determined using validated high-performance liquid chromatography method. Non-compartmental analysis was performed using WinNonlin program (Pharsight Inc., Apex, NC). A one-compartment pharmacokinetic model was applied to describe pharmacokinetics of alendronate. A peak plasma alendronate concentration of 33.10 ± 14.32 ng/mL was attained after 1.00 ± 0.16 h. The cumulative amount of alendronate excreted in urine and peak excretion rate were 731.28 ± 654.57 µg and 314.68 ± 395.43 µg/h, respectively. The model, which included first-order absorption rate for oral dosing, showed good fit to alendronate data obtained from plasma and urine. The absorption rate constant was 2.68 ± 0.95 h(-1). The elimination rate constants Kurine and Knon-ur were 0.005 ± 0.004 h(-1) and 0.42 ± 0.08 h(-1), respectively. The pharmacokinetics of alendronate in plasma and urine of healthy men can be predicted using one-compartment model, and thus the behavior of drug in plasma can be estimated from urinary excretion data.

Pulmonary delivery of nanosized alendronate for decorporation of inhaled heavy metals: formulation development, characterization and gamma scintigraphic evaluation.

CONTEXT: Medical management of heavy metal toxicity including radioactive ones is the cause of concern because of their increased use in energy production, healthcare and mining. As inhalation is one of the primary routes for internalization, a formulation is needed to trap metal(s) at the portal of entry itself. OBJECTIVE: Objective was to formulate and characterize a nanonized dry powder inhaler (DPI) formulation of alendronate sodium as potential inhalable antidote for chelating metal toxicants. METHODS: In vitro binding studies of alendronate with respect to seven non-radioactive heavy metals were carried out using UV-spectroscopy and HPLC. Nanonizing of alendronate particles was achieved by antisolvent precipitation using Pluronic-F68 as stabilizer. Characterization was done with the help of SEM, TEM FT-IR, XRD, DSC, NMR spectroscopy and PSD studies. In vitro and in vivo pulmonary deposition studies were carried out using gamma scintigraphy, followed by a limited pharmacokinetic study in humans. RESULTS: In vitro binding studies confirmed the chelating action of alendronate. Anderson cascade impaction showed that nano-alendronate exhibited significantly higher respirable fraction (58.25 ± 1.32%) compared to the micronized form (28.7 ± 0.59%). Scintigraphy results showed significant increase in the alveolar deposition of drug post-nanonizing. CONCLUSION: Results strongly indicate the role of nano-alendronate DPI as potential inhalable antidote for neutralizing heavy metal toxicity, including radio-metal contamination.

Transdermal delivery of bisphosphonates using dissolving and hydrogel-forming microarray patches: Potential for enhanced treatment of osteoporosis.

As of 2023, more than 200 million people worldwide are living with osteoporosis. Oral bisphosphonates (BPs) are the primary treatment but can cause gastrointestinal (GI) side effects, reducing patient compliance. Microarray (MAP) technology has the potential to overcome GI irritation by facilitating the transdermal delivery of BPs. This study examines the delivery of alendronic acid (ALN) and risedronate sodium (RDN) using dissolving and hydrogel-forming MAPs for osteoporosis treatment. In vivo testing on osteoporotic female Sprague Dawley rats demonstrated the efficacy of MAPs, showing significant improvements in mean serum and bone alkaline phosphatase levels, bone volume, and porosity compared to untreated bilateral ovariectomy (OVX) controls. Specifically, MAP treatment increased mean bone volume to 55.04 ± 2.25 % versus 47.16 ± 1.71 % in OVX controls and reduced porosity to 44.30 ± 2.97 % versus 52.84 ± 1.70 % in the distal epiphysis of the femur. In the distal metaphysis, bone volume increased to 43.32 ± 3.24 % in MAP-treated rats compared to 24.31 ± 3.21 % in OVX controls, while porosity decreased to 55.39 ± 5.81 % versus 75.69 ± 3.21 % in OVX controls. This proof-of-concept study indicates that MAP technology has the potential to be a novel, patient-friendly alternative for weekly osteoporosis management.

Alendronate-functionalized porous nano-crystalsomes mitigate osteolysis and consequent inhibition of tumor growth in a tibia-induced metastasis model.

Bone is one of the most prevalent sites of metastases in various epithelial malignancies, including breast cancer and this metastasis to bone often leads to severe skeletal complications in women due to its osteolytic nature. To address this, we devised a novel drug delivery approach using an Alendronate (ALN) functionalized self-assembled porous crystalsomes for concurrent targeting of Oleanolic acid (OA) and ALN (ALN + OA@NCs) to bone metastasis. Initially, the conjugation of both PEG-OA and OA-PEG-ALN with ALN and OA was achieved, and this conjugation was then self-assembled into porous crystalsomes (ALN + OA@NCs) by nanoemulsion crystallization. The reconstruction of a 3D single particle using transmission electron microscopy ensured the crystalline porous structure of ALN + OA@NCs, was well aligned with characteristic nanoparticle attributes including size distribution, polydispersity, and zeta potential. Further, ALN + OA@NCs showed enhanced efficacy in comparison to OA@NCs suggesting the cytotoxic roles of ALN towards cancer cells, followed by augmentation ROS generation (40.81%), mitochondrial membrane depolarization (57.20%), and induction of apoptosis (40.43%). We found that ALN + OA@NCs facilitated inhibiting osteoclastogenesis and bone resorption followed by inhibited osteolysis. In vivo activity of ALN + OA@NCs in the 4 T1 cell-induced tibia model rendered a reduced bone loss in the treated mice followed by restoring bone morphometric markers which were further corroborated bone-targeting effects of ALN + OA@NCs to reduce RANKL-stimulated osteoclastogenesis. Further, In vivo intravenous pharmacokinetics showed the improved therapeutic profile of the ALN + OA@NCs in comparison to the free drug, prolonging the levels of the drug in the systemic compartment by reducing the clearance culminating the higher accumulation at the tumor site. Our finding proposed that ALN + OA@NCs can effectively target and treat breast cancer metastasis to bone and its associated complications.

Alendronate-conjugated amphiphilic hyperbranched polymer based on Boltorn H40 and poly(ethylene glycol) for bone-targeted drug delivery.

A novel type of alendronate(ALE)-conjugated amphiphilic hyperbranched copolymer based on a hydrophobic hyperbranched Boltorn H40 (H40) core with ALE targeting moiety and many hydrophilic poly(ethylene glycol) (PEG) arms was synthesized as a carrier for bone-targeted drug delivery. The star copolymer H40-star-PEG/ALE was characterized using nuclear magnetic resonance (NMR), Fourier transformed infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) analysis. Benefiting from its highly branched structure, H40-star-PEG/ALE could form micelles in aqueous solution, which was confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The cytotoxicity and hemolysis of the H40-star-PEG/ALE micelles were evaluated via methylthiazoletetrazolium (MTT) assay against NIH/3T3 normal cells and red blood cell (RBC) lysis assay, respectively. As a model anticancer drug, doxorubicin (DOX) was encapsulated into the H40-star-PEG/ALE micelles. The anticancer activity of DOX-loaded micelles was evaluated by MTT assay against an HN-6 human head and neck carcinoma cell line. The strong affinity of H40-star-PEG/ALE micelles to bone was confirmed by the hydroxyapatite (HA) binding assay. These results indicate that the H40-star-PEG/ALE micelles are highly promising bone-targeted drug carriers for skeletal metastases.

Role of connexin 43 in the mechanism of action of alendronate: dissociation of anti-apoptotic and proliferative signaling pathways.

Bisphosphonates (BPs) inhibit osteocyte and osteoblast apoptosis via opening of connexin (Cx) 43 hemichannels and activating the extracellular signal regulated kinases ERKs. Previously, we hypothesized that intracellular survival signaling is initiated by interaction of BPs with Cx43. However, using whole cell binding assays with [(3)H]-alendronate, herein we demonstrated the presence of saturable, specific and high affinity binding sites in the Cx43-expressing ROS 17/2.8 osteoblastic cells, authentic osteoblasts and MLO-Y4 cells expressing Cx43 or not, as well as in HeLa cells lacking Cx43 expression and ROS 17/2.8 cells pretreated with agents that disassemble Cx channels. In addition, both BPs and the PTP inhibitor Na(3)VO(4) increased proliferation of cells expressing Cx43 or not. Furthermore, although BPs are internalized and inhibit intracellular enzymes in osteoclasts, whether the drugs penetrate non-resorptive bone cells is not known. To clarify this, we evaluated the osteoblastic uptake of AF-ALN, a fluorescently labeled analog of alendronate. AF-ALN was rapidly internalized in cells expressing Cx43 or not indicating that this process is not mediated via Cx43 hemichannels. Altogether, these findings suggest that although required for triggering intracellular survival signaling by BPs, Cx43 is dispensable for cellular BP binding, its uptake, as well as the proliferative effects of these agents.

Upper gastrointestinal tract transit times of tablet and drinkable solution formulations of alendronate: a bioequivalence and a quantitative, randomized study using video deglutition.

The bioequivalence and upper digestive tract transit time of a drinkable solution of 70 mg/100 mL alendronate was compared to reference tablets. A randomized, single- dose, two-way crossover study of the rate of urinary recovery of alendronate during 36 h (AE((0-36 h))) by HPLC, in 104 healthy young male volunteers, showed that AE((0-36 h)) and the maximum excretion rate (R (max)) were within the accepted range of bioequivalence 81.8-105.7 and 81.7-106.2, respectively. To characterize the oesophageal passage time of the two alendronate formulations, we performed a randomized, controlled study, in 24 healthy men and women (mean 52 years old), who took the formulations standing or lying down, by an X-ray video deglutition system. When taken in the standing position, both formulations had equal mean transit times from mouth to stomach and tablet disintegration but data dispersion was significantly smaller with the liquid form. When taken in lying position, drinkable alendronate had shorter and less variable median transit times compared to the tablets. These results show that the drinkable alendronate formulation is bioequivalent to the tablets and may be advantageous in patients in whom the transit or disintegration of the tablets is impaired.

Design and synthesis of novel bone-targeting dual-action pro-drugs for the treatment and reversal of osteoporosis.

There is an important medical need for effective therapies to redress the general bone loss associated with advanced osteoporosis. Prostaglandin E(2) and related EP4 receptor agonists have been shown to stimulate bone regrowth but their use has been limited by systemic side effects. Herein is described the design and synthesis of novel dual-action bone-targeting conjugate pro-drugs where two classes of active agents, a bone growth stimulating prostaglandin E(2) EP4 receptor subtype agonist (5 or 6) and a bone resorption inhibitor bisphosphonate, alendronic acid (1), are coupled using metabolically labile carbamate or 4-hydroxyphenylacetic acid based linkers. Radiolabelled conjugates 9, 11a/b and 25 were synthesized and evaluated in vivo in rats for uptake of the conjugate into bone and subsequent release of the EP4 agonists over time. While conjugate 11a/b was taken up (9.0% of initial dose) but not released over two weeks, conjugates 9 and 25 were absorbed at 9.4% and 5.9% uptake of the initial dose and slowly released with half-lives of approximately 2 weeks and 5 days respectively. These conjugates were well tolerated and offer potential for sustained release and dual synergistic activity through their selective bone targeting and local release of the complimentary active components.

Alendronate liposomes for antitumor therapy: activation of γδ T cells and inhibition of tumor growth.

Circulating γδ T cells are cytotoxic lymphocytes that are unique to primates. Recent -studies have shown that amino-bisphosphonates (nBP) activate γδ T cells to kill tumor cells in an indirect mechanism, which requires antigen presenting cells (APC). We hypothesized that selective targeting of nBP to monocytes would result in a more potent γδ T cells activation in circulation, and in tissue associated macrophages (TAM) following monocytes-laden drug extravasation and liposomes accumulation at the tumor site. In addition, inhibition of TAM by alendronate liposomes (ALN-L) is expected. ALN was targeted exclusively to monocytes, but not to lymphocytes, by encapsulating it in negatively-charged liposomes. The proportion of human γd-T cells in the CD3(+) population following treatment with ALN-L or the free drug was increased, from 5.6 ± 0.4% to 50.9 ;± 12.2% and 49.5 ± 12.9%, respectively. ALN solution and liposomes treatments resulted in an increased, and in a dose dependent manner, TNFα secretion from h-PBMC. Preliminary results showed that ALN-L inhibited tumor growth in a nude mouse breast tumor model. It is suggested that enhanced activation of γδ T cells could be obtained due to interaction with circulating monocytes as well as by TAM endocytosing liposomal nBP leading to a potentiated anti-tumor effect of nBP. It should be noted that this could be validated only in primates/humans since γδ T cells are unique in these species.

Inhalation of alendronate nanoparticles as dry powder inhaler for the treatment of osteoporosis.

The precipitation technique was used to prepare non-polymeric alendronate nanoparticles. The influence of various formulation parameters on the average particle size was investigated and the effect of various stabilizers (PVA, tween, chitosan, alginate, PEG, HPMC, poloxomers) was evaluated. The selection of surfactant was a key factor to produce particles with desired properties. Poloxomer F68 was found best in achieving the minimum particle size and providing physical stability to the drug. On basis of preliminary trials, a central composite design was employed to study the effect of independent variables, drug concentration (X1), antisolvent volume (X2), stirring speed (X3), and stabilizer concentration (X4) on the average particle size. The drug and stabilizer concentrations exhibited a more significant effect on a dependent variable. The particle size varied from 62 to 803.3 nm depending upon the significant terms. The validation of optimization study, performed using six confirmatory runs, indicated very high degree of prognostic ability of response surface methodology, with mean percentage error (±SD) as -2.32 ± 2.47. The minimum particle size (44.11 nm) was predicted at 10 mg/ml drug concentration, 20 ml antisolvent volume, 925 rpm stirring speed, and 8.5% stabilizer concentration with 98.16% experimental validity. Respirable fraction for optimized nanosized alendronate (43.85% ± 0.52%) was significantly higher when compared with commercial alendronate (17.6 ± 0.32). Mass median aerodynamic diameter of designed particles was 3.45 µm with geometric standard deviation of 2.10.

Dendritic poly(ethylene glycol) bearing paclitaxel and alendronate for targeting bone neoplasms.

Poly(ethylene glycol) (PEG) is the most popular polymer for protein conjugation, but its potential as carrier of low molecular weight drugs has been limited by the intrinsic low loading, owing to its chemical structure. In fact, only the two end chain groups of PEG can be modified and exploited for drug coupling. We have demonstrated that by synthesizing a dendrimer structure at the polymer end chains, it is possible to increase the drug payload and overcome this limitation. Furthermore, this approach can be improved by using heterobifunctional PEG. These polymers allow the precise linking of two different drugs, or a drug and a targeting agent, on the same polymeric chain. Heterobifunctional PEG-dendrimers have been obtained with defined chemical structures leading to their attractive use as drug delivery systems. In fact, they offer a double benefit; first, the possibility to choose the best drug/targeting agent ratio, and second, the separation of the two functions, activity and targeting, which are coupled at the opposite polymer end chains. In this study, we investigated the role of a PEG-dendrimer, H(2)N-PEG-dendrimer-(COOH)(4), as carrier for a combination of paclitaxel (PTX) and alendronate (ALN). PTX is a potent anticancer drug that is affected by severe side effects originating from both the drug itself and its solubilizing formulation, Cremophor EL. ALN is an aminobiphosphonate used for the treatment of osteoporosis and bone metastases as well as a bone-targeting moiety. The PTX-PEG-ALN conjugate was designed to exploit active targeting by the ALN molecule and passive targeting through the enhanced permeability and retention (EPR) effect. Our conjugate demonstrated a great binding affinity to the bone mineral hydroxyapatite in vitro and an IC(50) comparable to that of the free drugs combination in human adenocarcinoma of the prostate (PC3) cells. The PTX-PEG-ALN conjugate exhibited an improved pharmacokinetic profile compared with the free drugs owed to the marked increase in their half-life. In addition, PTX-PEG-ALN could be solubilized directly in physiological solutions without the need for Cremophor EL. The data presented in this manuscript encourage further investigations on the potential of PTX-PEG-ALN as treatment for cancer bone metastases.

Effects of amines on percutaneous absorption of alendronate.

OBJECTIVE: The aim of this study was to examine the effects of amines on the permeation of alendronate using solution formulations and pressure-sensitive adhesive (PSA) transdermal delivery systems (TDS). MATERIALS AND METHODS: Monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), diethylamine (DEYA), and triethylamine (TEYA) at concentrations of 3, 6, and 10% were added to propylene glycol (PG) containing 6% caprylic acid. In vitro and in vivo experiments were conducted using alendronate solution and PSA TDS formulations. RESULTS: When using saturated solution formulations, 3% TEA and 10% DEYA showed high permeation rates of 8.20 ± 0.80 and 7.87 ± 0.18 µg/cm(2)/h, respectively. The maximum permeation flux of 1.79 ± 0.28 µg/cm(2)/h from 1 mg/ml solution was obtained with the addition of 10% DEYA followed by the addition of 10% TEYA (1.72 ± 0.72 µg/cm(2)/h). The highest enhancement factor of 1.86 was obtained with alendronate PSA TDS containing 10% MEA compared with no amine. In the in vivo study, the amount remaining to be excreted (ARE) at time 0 (Ae(∞)) and ARE at time t [Ae(t)] differed between TDS and oral delivery significantly (P < 0.01). The TDS containing 10% MEA showed the highest Ae(∞) (19.5 ± 6.93 µg), which was 2.7- and 2.2-fold, compared with oral and no amine administration, respectively. CONCLUSION: Based on the results, TDS with 10% MEA in PG containing 6% caprylic acid could be a good candidate for the alendronate TDS.

Development, optimisation and evaluation of chitosan nanoparticles of alendronate against Alzheimer's disease in intracerebroventricular streptozotocin model for brain delivery.

The current study aimed to develop alendronate (ALN)-loaded chitosan nanoparticles (CS-ALN-NPs) for brain delivery via intranasal route. These CS-ALN-NPs reduced the peripheral side effects and released ALN directly to brain. These NPs were formulated through ionic gelation technique by mixing sodium tripolyphosphate (1.5 mg/ml) in ALN-CS (1.75 mg/ml) solution. CS-ALN-NPs attained 135.75 ± 5.80 nm, 0.21 ± 0.013, 23.8 ± 3.69 mV, 72.46 ± 0.879% and 30.92 ± 0.375% mean particle size, PDI, zeta potential, entrapment efficiency and loading capacity, respectively. Furthermore, the TEM and SEM analysis of CS-ALN-NPs, respectively, revealed the particle size in 200 nm range and spherical shape. The in vitro and ex vivo release profile revealed a sustained drug release through CS-ALN-NPs as compared to pure drug solution. Also these NPs acquired a high concentration in mice brain and better pharmacokinetic profile than ALN solution (intranasal) CS-ALN-NPs were then evaluated against intracerebroventricular-streptozotocin (ICV-STZ) induced Alzheimer's disease (AD)-like pathologies in mice. The intranasal CS-ALN-NP altered the ICV-STZ induced neurobehavioral, neurochemical and histopathological changes in mice. These effects were significant to those of ALN solution (intranasal). The neuroprotective potential of CS-ALN-NPs observed in ICV-STZ mice model of AD may be a promising brain-targeted delivery system for AD treatment along with further extensive exploration at both pre-clinical and clinical edge. HIGHLIGHTS CS-ALN-NPs were developed and optimised to overcome the poor pharmacokinetic profile and associated side effects of ALN CS-ALN-NPs showed particle size within 200 nm range as well as controlled and sustained release in in vitro release study These optimised NPs of ALN attained higher brain:blood ratio and better pharmacokinetic profile (Cmax, tmax, AUC) CS-ALN-NPs markedly altered ICV STZ induced impairment in cognitive functions of mice and changes in APP processing, neuroinflammatory cytokines and other biochemical parameters in mice hippocampus.

188Re(CO)3-dipicolylamine-alendronate: a new bisphosphonate conjugate for the radiotherapy of bone metastases.

The palliation of pain due to bone metastases using targeted compounds containing beta-emitters such as rhenium-188 ((188)Re) is an accepted and effective form of treatment. Here, we describe the efficient synthesis and preclinical evaluation of (188)Re(CO)(3)-dipicolylamine(DPA)-alendronate, a novel bifunctional bisphosphonate for the palliative treatment of bone metastases. (188)Re(CO)(3)-DPA-alendronate can be easily synthesized with high specific activities and yields (18.8 GBq/mg, radiochemical yield > or =96%) in two steps using kit-based methodology, and in contrast with the clinically approved bisphosphonate (186/188)Re-HEDP, it forms inert, single species that have been well-characterized. In vivo imaging and biodistribution studies demonstrate that (188)Re(CO)(3)-DPA-alendronate is superior to (188)Re-HEDP in targeting and accumulating in areas of high metabolic bone activity while having low soft-tissue uptake. In addition to these studies, a simple and convenient new method for purifying its precursor, fac-[(188)Re(CO)(3)(H(2)O)(3)](+), is described.

Adverse events, bone mineral density and discontinuation associated with generic alendronate among postmenopausal women previously tolerant of brand alendronate: a retrospective cohort study.

BACKGROUND: A rise in gastrointestinal (GI) adverse events (AEs) and a decline in bone mineral density (BMD) was observed in patients previously tolerant to brand alendronate shortly after generic versions were introduced in July 2005 to the Canadian market. The objective of our study was to quantify changes in AE rates and BMD scores, as well as associated alendronate discontinuation among patients before and after switch from brand to generic alendronate. METHODS: A chart review of postmenopausal women 50 years of age and older between 2003 and 2007 was conducted in two specialized tertiary care referral centers. Patients on alendronate both before and after July 2005 were included. The change in the number of AEs, changes in BMD and associated alendronate discontinuation was compared before and after the switch from brand to generic alendronate. RESULTS: 301 women with an average age of 67.6 years (standard deviation (SD) = 9.5) had a total of 47 AEs between July 2003 and December 2007 that resulted in discontinuation of the medication. There was a significant increase in the rate of AEs per patient-months-at-risk from 0.0001 before to 0.0044 after October 2005 (p < 0.001). The most common AEs were GI in nature (stomach pain, GI upset, nausea, and reflux). In addition, 23 patients discontinued alendronate due to BMD reduction after January 2006. In these patients, BMD scores were significantly reduced from their prior BMD measures (change of -0.0534, p < 0.001 for spine BMD and change of -0.0338, p = 0.01 for femur BMD). Among patients who discontinued due to BMD reduction, BMD was stable in the period prior to January 2006 (change of -0.0066, p = 0.5 for spine BMD and change of 0.0011, p = 0.9 for femur BMD); however, testing for reduction after January 2006 in BMD measures (one-sided T-test) revealed there was a significant reduction in BMD scores for both anatomic sites (change of -0.0321, p = .005 for spine, change of -0.0205, p = 0.05 for femur). CONCLUSIONS: Patients who were previously stable on doses of brand alendronate experienced an increase in AEs causing discontinuation after introduction of automatic substitution to generic alendronate. In addition, reductions in BMD were observed in some patients who had stable BMDs before January 2006. Given the substantial increase in AEs, generic alendronate may not be as well tolerated as brand alendronate.