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

Threading the needle: Achieving simplicity and performance in cellulose alkanoate ω-carboxyalkanoates for amorphous solid dispersion

Most active pharmaceutical ingredients (APIs) suffer from poor water solubility, often keeping them from reaching patients. To overcome the issues of poor drug solubility and subsequent low bioavailability, amorphous solid dispersions (ASDs) have garnered much attention. Cellulose ester derivatives are of interest for ASD applications as they are benign, sustainable-based, and successful in commercial drug delivery systems, e.g. in osmotic pump systems and as commercial ASD polymers. Synthesis of carboxy-pendant cellulose esters is a challenge, due in part to competing reactions between carboxyls and hydroxyls, forming ester crosslinks. Herein we demonstrate proof-of-concept for a scalable synthetic route to simple, yet highly promising ASD polymers by esterifying cellulose polymers through ring-opening of cyclic succinic or glutaric anhydride. We describe the complexity of such ring-opening reactions, not previously well-described, and report ways to avoid gelation. We report synthesis, characterization, and preliminary in vitro ASD evaluations of fifteen such derivatives. Synthetic routes were designed to accommodate these criteria: no protecting groups, no metal catalysts, mild conditions with standard reagents, simple purification, and one-pot synthesis. Finally, these designed ASD polymers included members that maintained fast-crystallizing felodipine in solution and release it from an ASD at rather high 20 % drug loading (DL).

Mechanistic PK-PD model of alendronate treatment of postmenopausal osteoporosis predicts bone site-specific response

Alendronate is the most widely used drug for postmenopausal osteoporosis (PMO). It inhibits bone resorption, affecting osteoclasts. Pharmacokinetics (PK) and pharmacodynamics (PD) of alendronate have been widely studied, but few mathematical models exist to simulate its effect. In this work, we have developed a PK model for alendronate, valid for short- and long-term treatments, and a mechanistic PK-PD model for the treatment of PMO to predict bone density gain (BDG) at the hip and lumbar spine. According to our results, at least three compartments are required in the PK model to predict the effect of alendronate in both the short and long terms. Clinical data of a 2-year treatment of alendronate, reproduced by our PK-PD model, demonstrate that bone response is site specific (hip: 7% BDG, lumbar spine: 4% BDG). We identified that this BDG is mainly due to an increase in tissue mineralization and a decrease in porosity. The difference in BDG between sites is linked to the different loading and dependence of the released alendronate on the bone-specific surface and porosity. Osteoclast population diminishes quickly within the first month of alendronate treatment. Osteoblast population lags behind but also falls due to coupling of resorption and formation. Two dosing regimens were studied (70 mg weekly and 10 mg daily), and both showed very similar BDG evolution, indicating that alendronate accumulates quickly in bone and saturates. The proposed PK-PD model could provide a valuable tool to analyze the effect of alendronate and to design patient-specific treatments, including drug combinations.

Development of a Pediatric Relative Bioavailability/Bioequivalence Database and Identification of Putative Risk Factors Associated With Evaluation of Pediatric Oral Products

Generally, bioequivalence (BE) studies of drug products for pediatric patients are conducted in adults due to ethical reasons. Given the lack of direct BE assessment in pediatric populations, the aim of this work is to develop a database of BE and relative bioavailability (relative BA) studies conducted in pediatric populations and to enable the identification of risk factors associated with certain drug substances or products that may lead to failed BE or different pharmacokinetic (PK) parameters in relative BA studies in pediatrics. A literature search from 1965 to 2020 was conducted in PubMed, Cochrane Library, and Google Scholar to identify BE studies conducted in pediatric populations and relative BA studies conducted in pediatric populations. Overall, 79 studies covering 37 active pharmaceutical ingredients (APIs) were included in the database: 4 bioequivalence studies with data that passed BE evaluations; 2 studies showed bioinequivalence results; 34 relative BA studies showing comparable PK parameters, and 39 relative BA studies showing differences in PK parameters between test and reference products. Based on the above studies, common putative risk factors associated with differences in relative bioavailability (DRBA) in pediatric populations include age-related absorption effects, high inter-individual variability, and poor study design. A database containing 79 clinical studies on BE or relative BA in pediatrics has been developed. Putative risk factors associated with DRBA in pediatric populations are summarized.

The potential impact of new effervescent alendronate formulation on compliance and persistence in osteoporosis treatment

Osteoporotic fractures are a public health problem and their incidence and subsequent economic and social costs are expected to rise in the next future. Different drugs have been developed to reduce osteoporosis and the risk of osteoporotic fractures, and among them, antiresorptive agents, and in particular oral alendronate, are the most widely utilized. However, one of the most common problems with antiresorptive drugs is poor adherence to treatment, which is associated with a high fracture incidence and with an increase in hospitalization costs. One of the main reasons of poor adherence to these treatments is the occurrence of adverse events, mainly at gastrointestinal (GI) level, including dyspepsia, dysphagia, and esophageal ulcers. In light of these considerations the aim of this paper is to perform a literature review to show the pathophysiologic bases of GI alendronate-induced adverse events and how new bisphosphonate formulations like effervescent alendronate can improve compliance and persistence to treatment and decrease the fracture rate incidence in osteoporotic patients.

Considerations regarding adherence of anti-osteoporosis therapy

Osteoporosis remains a challenging disease to treat due to a number of barriers including patient adherence to therapies. One of the most recent advances has been the development of the Fracture Risk Assessment Tool, which is helpful in conveying fracture risk to patients and providing treatment guidance to clinicians. The decision to use an anti-osteoporosis therapy must be tailored to the patient's specific clinical scenario. The bisphosphonates are first-line agents in the treatment of osteoporosis and are efficacious in substantially reducing fracture risk between 25% and 70% on average depending on fracture site. Compliance with oral bisphosphonate pills can be poor, resulting in a significant deterrent to the proper management of osteoporosis. Non-pill forms of bisphosphonate and nonbisphosphonate therapy are available for the treatment of osteoporosis and may increase compliance. Among these is Binosto, a new formulation of weekly effervescent alendronate, as well as intravenous bisphosphonates, teriparatide, and subcutaneously administered denosumab, which are all costly medications and are unlikely to become the mainstay of treatment over the oral bisphosphonate pills. Having a detailed conversation between the patient and physician is essential to the development of a tailored treatment plan that will decrease fracture risk.

A drinkable formulation of alendronate: potential to increase compliance and decrease upper GI irritation

Osteoporosis is a growing public health problem and several drugs have been developed in the past two decades to offer pharmacological solutions both in prevention and in therapy. Alendronate was the first compound registered as an anti-fracture agent and also the most prescribed drug worldwide for osteoporosis. Patient compliance is a major problem with alendronate, with studies demonstrating that 50-60% of patients discontinue treatment within one year. Dysphagia and swallowing difficulties are common especially among elderly people and the perceived potential for upper GI problems is a barrier to good long-term adherence. As non-persistence and non-compliance are linked to increased risk of fractures, efforts have been made to develop forms of alendronate which are more acceptable to patients. Among these, the drinkable formulations have the potential great convenience, simplicity of administration and reduction in gastro-intestinal side effects. In addition these novel soluble products are equivalent in cost to generic alendronate tablets. The approaches to improve adherence to an old and effective medication for osteoporotic patients will be reviewed in this report, with a special focus on the recently marketed product Bonasol 70 mg oral solution.