Oesophageal transport of solid dosage forms depends on body position, swallowing volume and pharyngeal propulsion velocity

Investigation of real-life drug intake behaviour in older adults and geriatric patients in Northern Germany - A biopharmaceutical perspective

Dosing conditions (type and amount of accompanying fluid, the type of food, the time of administration, and dosage form modifications such as crushing tablets) are critical and affect the performance of oral dosage forms in the gastrointestinal tract and thus bioavailability. Because older adults are the primary users of medications and are more susceptible to adverse effects, it is important to understand how they take their medications in order to reduce risks and increase benefits of the pharmacotherapy. The aim of the study was to investigate the real-life drug intake behaviour in geriatric patients and older adults and discuss their influence on drug absorption after oral administration. The data from two settings home vs. hospital and genders women vs. men were presented. A questionnaire study was performed among people aged at least 65 years from two settings (hospital vs. home), recruited mostly from community pharmacies and a regional hospital in Mecklenburg - Western Pomerania. The obtained data demonstrates that older adults and geriatric patients take their medications in the same way regardless of the setting and gender. There were no significant differences. Interviewed participants were mostly adherent to the doctor's recommendations and mostly took their medications in the same way every day. Medications are most commonly taken with a small (100 mL) or large (200 mL) glass of noncarbonated water, after food (during or after breakfast 64 % of intakes in the morning and during or after dinner 81 % of intakes in the evening). Meal usually consisted of bread, either with jam or honey (breakfast), or ham and cheese (dinner). All reported dosage form modifications were made to tablets. In almost all cases it was splitting the tablet, which was performed due to doctor's indication.

A Window for Enhanced Oral Delivery of Therapeutics via Lipid Nanoparticles

Oral administration of dosage forms is convenient and beneficial in several respects. Lipid nanoparticulate dosage forms have emerged as a useful carrier system in deploying low solubility drugs systemically, particularly class II, III, and IV drugs of the Biopharmaceutics Classification System. Like other nanoparticulate delivery systems, their low size-to-volume ratio facilitates uptake by phagocytosis. Lipid nanoparticles also provide scope for high drug loading and extended-release capability, ensuring diminished systemic side effects and improved pharmacokinetics. However, rapid gastrointestinal (GI) clearance of particulate delivery systems impedes efficient uptake across the mucosa. Mucoadhesion of dosage forms to the GI mucosa results in longer transit times due to interactions between the former and mucus. Delayed transit times facilitate transfer of the dosage form across the mucosa. In this regard, a balance between mucoadhesion and mucopenetration guarantees optimal systemic transfer. Furthermore, the interplay between GI anatomy and physiology is key to ensuring efficient systemic uptake. This review captures salient anatomical and physiological features of the GI tract and how these can be exploited for maximal systemic delivery of lipid nanoparticles. Materials used to impart mucoadhesion and examples of successful mucoadhesive lipid nanoformulations are highlighted in this review.

Development of Test Programs for the Biorelevant Characterization of Esophageal-Applied Dosage Forms

In the local treatment of the esophageal mucosa, the retention time of the different dosage forms, such as tablets, films or liquids, is of high relevance for the effective treatment of diseases. Unfortunately, there are only few in vitro models describing the esophageal route of administration. To predict the behaviour of an esophageal-applied dosage form, it is necessary to simulate the site of application in a biorelevant way. The aim of this work was to develop two test setups for an esophageal peristalsis model which was described in a previous study. Different parameters such as flow rate, peristalsis, angle of inclination or mucous membrane were varied or introduced into the model. A stimulated and unstimulated modus were developed and tested with two different dosage forms. The time until the dosage form was cleared from the in vitro model was shorter with the stimulated than with the unstimulated modus. Also, esophageal-applied films had a prolonged transit time compared to a viscous syrup. The modification of the simulated esophageal surface made it possible to estimate the retention time of the dosage forms. It could be demonstrated that the residence time of a dosage form depends on different parameters affecting each other.

A Short History of High-Resolution Esophageal Manometry

High-resolution esophageal manometry (HRM) utilizes sufficient pressure sensors such that intraluminal pressure is monitored as a continuum along luminal length, similar to time viewed as a continuum on polygraph tracings in 'conventional' manometry. When HRM is coupled with pressure topography plotting, and pressure amplitude is transformed into spectral colors with isobaric areas indicated by same-colored regions, "Clouse plots" are generated. HRM has several advantages compared to the technology that it replaced: (1) the contractility of the entire esophagus can be viewed simultaneously in a uniform standardized format, (2) standardized objective metrics of peristaltic and sphincter function can be systematically applied for interpretation, and (3) topographic patterns of contractility are more easily recognized with greater reproducibility. Leveraging these advantages led to the current standard for the interpretation of clinical esophageal HRM studies, the Chicago Classification (CC), now in its fourth iteration. Compared to conventional manometry, HRM has vastly improved the sensitivity for detecting achalasia, largely due to the objectivity and accuracy of identification of impaired esophagogastric junction (EGJ) relaxation. Additionally, it has led to the subcategorization of achalasia into three clinically relevant subtypes, differentiated by the contractile function of the esophageal body, and identified an additional disorder of EGJ outflow obstruction wherein esophageal peristalsis is preserved. Headway has also been made in understanding hypocontractile and hypercontractile conditions. In summary, HRM and the CC process have revolutionized our understanding of esophageal motility and motility disorders. Moving forward, there will always be remaining challenges, but we now have the tools to meet them.

Comparing the gastric emptying of 240 mL and 20 mL water by MRI and caffeine salivary tracer technique

Gastrointestinal fluid volumes are a crucial parameter for dissolution and absorption of orally taken medications. Most often 240 mL are used in clinical standard setups. Nonetheless, surveys in patient populations revealed dramatically lower volumes for intake of oral medications in real life and even in some clinical studies reduced fluid volumes are common. These reductions might have serious impact on pharmacokinetics. Thus, it was the aim of this study to compare the gastric emptying of 240 mL and 20 mL of water in 8 healthy volunteers. For investigation of gastric fluid volumes Magnetic Resonance Imaging with strongly T2 weighted sequences was used. Gastric emptying was additionally quantified via caffeine pharmacokinetics measured in saliva. The absolute gastric volumes after intake of 240 mL or 20 mL obviously differed by factor 10 but relative gastric emptying expressed as fraction per time was nearly comparable. Only slighter slower emptying after intake of 20 mL was observed. Salivary caffeine pharmacokinetics representing mass transfer from stomach to small intestine after intake of different volumes did not differ. The absorbed caffeine fraction and emptied gastric volume fraction correlated well after intake of 240 mL, but not after intake of 20 mL, indicating a higher influence of secretion on gastric volume measurements after intake of smaller volumes. Relative gastric emptying as measured with MRI and salivary caffeine method was only slightly delayed, thus transfer of orally administered drug fraction could be comparable even with lower fluid intake as can be seen by comparable caffeine pharmacokinetics. Nonetheless, the considerably reduced volumes might interfere with dissolution and absorption.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Influence of the geometry of 3D printed solid oral dosage forms on their swallowability

3D printing can be used to realise a wide variety of geometries of oral dosage forms. In this work, the swallowability of 3D-printed dosage forms with comparable size and different shape using fused deposition modelling (FDM) from isomalt was investigated in a controlled, randomised crossover study design. To produce the required number of dosage forms, a commercial 3D printer was modified with regard to product safety and production time. The modifications carried out permit the printing of 4 pharmaceutical forms simultaneously as well as the printing of rigid filaments. Six 3D-printed placebo objects and two compressed placebo reference objects were tested by 12 subjects in a blinded design. A questionnaire was used to assess swallowability, foreign body sensation at the moment of swallowing, persistent foreign body sensation after swallowing and pain after swallowing. Furthermore, the amount of additional water drunk after administration was documented. With the modified printer, the required 576 test objects could be printed within a few days with good reproducibility. In all questions, the best results were obtained for the printed and compressed oblong tablets, followed by the printed and compressed round tablets, the football and the sphere. The worst results were obtained for the pyramid closely followed by the cuboctahedron. The study shows that the variety of shapes of oral dosage forms made possible by 3D printing needs to be tested in swallowability studies, as not every shape is also easy to swallow.

Assessment of oral solid dosage forms administration manner and acceptability

Taking oral solid dosage forms (OSDFs) safely and effectively is particularly important. This study aimed to determine the pattern and knowledge about the proper criteria of OSDF administration and the consumers’ preferences toward OSDF characteristics. The aims of this study were achieved by cross-sectional survey through open and closed-ended questionnaires, and the presence of the main OSDF administration recommendations of a sample of 32 OSDF drug leaflets was assessed. Based on a simple random sample of 250 volunteers, we found inadequate compliance with the OSDF medicine administration criteria. We also found an absence of the main recommendations of OSDF drug administration on most of the investigated OSDF drug leaflets. Conventional white, round tablets were found to be the most preferred type of OSDF drug. These findings can be valuable to pharmaceutical manufacturers, regulatory agencies, and pharmacists to enhancing patient awareness and compliance with OSDF administration for safe and effective drug administration.

Multi-Analytical Framework to Assess the In Vitro Swallowability of Solid Oral Dosage Forms Targeting Patient Acceptability and Adherence

A lack of effective intervention in addressing patient non-adherence and the acceptability of solid oral dosage forms combined with the clinical consequences of swallowing problems in an ageing world population highlight the need for developing methods to study the swallowability of tablets. Due to the absence of suitable techniques, this study developed various in vitro analytical tools to assess physical properties governing the swallowing process of tablets by mimicking static and dynamic stages of time-independent oral transitioning events. Non-anatomical models with oral mucosa-mimicking surfaces were developed to assess the swallowability of tablets; an SLA 3D printed in vitro oral apparatus derived the coefficient of sliding friction and a friction sledge for a modified tensometer measured the shear adhesion profile. Film coat hydration and in vitro wettability was evaluated using a high-speed recording camera that provided quantitative measurements of micro-thickness changes, simulating static in vivo tablet–mucosa oral processing stages with artificial saliva. In order to ascertain the discriminatory power and validate the multianalytical framework, a range of commonly available tablet coating solutions and new compositions developed in our lab were comparatively evaluated according to a quantitative swallowability index that describes the mathematical relationship between the critical physical forces governing swallowability. This study showed that the absence of a film coat significantly impeded the ease of tablet gliding properties and formed chalky residues caused by immediate tablet surface erosion. Novel gelatin- and λ-carrageenan-based film coats exhibited an enhanced lubricity, lesser resistance to tangential motion, and reduced stickiness than polyvinyl alcohol (PVA)–PEG graft copolymer, hydroxypropyl methylcellulose (HPMC), and PVA-coated tablets; however, Opadry^® EZ possessed the lowest friction–adhesion profile at 1.53 a.u., with the lowest work of adhesion profile at 1.28 J/mm². For the first time, the in vitro analytical framework in this study provides a fast, cost-effective, and repeatable swallowability ranking method to screen the in vitro swallowability of solid oral medicines in an effort to aid formulators and the pharmaceutical industry to develop easy-to-swallow formulations.

A Difficult Pill to Swallow: An Investigation of the Factors Associated with Medication Swallowing Difficulties

BACKGROUND

Many medications are available as solid oral dosage forms such as tablets and capsules; however, some people find these medications difficult to swallow.

AIM

To identify whether certain psychological, oral sensory, and oral motor characteristics contribute to medication swallowing difficulties.

METHODS

A sample of healthy adults from two academic institutions in Brisbane were assessed for their experiences with swallowing solid oral dosage forms, food preferences, and food neophobia. The gag reflex, oral cavity size, fungiform papillae count, and chewing efficacy were also evaluated followed by a capsule-swallowing task. Primary outcome was the incidence of medication swallowing difficulties. Secondary outcomes were the association of medication swallowing difficulties with psychological, oral sensory, and oral motor factors.

RESULTS

Of 152 subjects, 32% reported difficulty swallowing tablets or capsules whole. This group was significantly more likely to have had a memory of choking on medications compared to those without medication swallowing difficulties (OR = 7.25, p < 0.05). Current medication swallowing difficulties were significantly associated with a smaller mouth cavity size (OR = 2.98, p < 0.05), a higher density of taste receptors on the tongue (OR = 3.27, p < 0.05), and were higher among those who chewed a jelly candy to non-homogenous particle size (OR = 4.1, p < 0.05). Current medication swallowing difficulties were associated with lower confidence in swallowing large capsules (000 size: OR = 0.47, 00 size: OR = 0.39, p < 0.05). No associations were found between medication swallowing difficulties and the gag reflex or food neophobia.

CONCLUSION

A combination of heightened oral perception characterized by a small oral cavity and high taste sensitivity compounded by a past choking episode on medications may be precipitating factors for medication swallowing difficulties. These factors may be helpful in identifying individuals who are more likely to experience difficulty swallowing medications.

Updates on diagnostic modalities for esophageal dysphagia

Esophageal dysphagia is a common symptom in adults. Fluoroscopic contrast studies, endoscopy, and esophageal manometry have been used in the diagnosis of esophageal dysphagia for many years. The diagnostic yield has been improved with new test protocols that highlight abnormal bolus transit in the esophagus and outflow obstruction, as well as new high-definition and high-resolution technical advances in equipment. Functional luminal impedance planimetry and the addition of impedance to high-resolution esophageal manometry have also allowed the assessment of new parameters to better understand esophageal structure and function. In this concise review, we describe the role and utility of various diagnostic modalities in the assessment of patients with esophageal dysphagia.

Enhancing High-Resolution Esophageal Manometry: Use of Ancillary Techniques and Maneuvers

High-resolution manometry evaluates esophageal motor function using 10 supine water swallows. Superimposing impedance over high-resolution manometry pressure topography assesses the relationship between contraction and bolus propulsion and identifies inadequate clearance. Ancillary techniques and maneuvers augment the standard supine high-resolution manometry evaluation by challenging peristaltic function. Increasing bolus volume (rapid drink challenge) and altering bolus consistency (standardized test meal, solid swallows) enhance identification of esophageal outflow obstruction syndromes. Physiologic maneuvers (multiple rapid swallows, abdominal compression) address the ability of the esophageal smooth muscle to augment contraction vigor. Pharmacologic challenge is less commonly used clinically, and elucidates pathophysiology of esophageal motor disorders.

The EsoCap-system - An innovative platform to drug targeting in the esophagus

For the therapy of esophageal diseases such as eosinophilic esophagitis, there are no possibilities of local targeted therapy. This publication describes a novel, innovative drug delivery concept, that enables a targeted, long-lasting administration of drug substances to the esophageal mucosa. In addition to a comprehensive in-vitro characterization of the dosage form, this work includes a proof-of-concept study with healthy volunteers, which shows the functionality and acceptance of this novel drug delivery concept. This novel drug delivery technology enables for the first time a targeted, local and long-lasting therapy of the esophagus.

Comparison of In Vitro and In Vivo Results Using the GastroDuo and the Salivary Tracer Technique: Immediate Release Dosage Forms under Fasting Conditions

The fasted state administration of immediate release (IR) dosage forms is often regarded as uncritical since physiological aspects seem to play a minor role for disintegration and drug release. However, recent in vivo studies in humans have highlighted that fasted state conditions are in fact highly dynamic. It was therefore the aim of this study to investigate the disintegration and drug release behavior of four different IR formulations of the probe drug caffeine under physiologically relevant conditions with the aid of the GastroDuo. One film-coated tablet and three different capsule formulations based on capsule shells either made from hard gelatin or hydroxypropylmethyl cellulose (HPMC) were tested in six different test programs. To evaluate the relevance of the data generated, the four IR formulations were also studied in a four-way cross-over study in 14 healthy volunteers by using the salivary tracer technique (STT). It could be shown that the IR formulations behaved differently in the in vitro test programs. Thereby, the simulated parameters affected the disintegration and dissolution behavior of the four IR formulations in different ways. Whereas drug release from the tablet started early and was barely affected by temperature, pH or motility, the different capsule formulations showed a longer lag time and were sensitive to specific parameters. However, once drug release was initiated, it typically progressed with a higher rate for the capsules compared to the tablet. Interestingly, the results obtained with the STT were not always in line with the in vitro data. This observation was due to the fact that the probability of the different test programs was not equal and that certain scenarios were rather unlikely to occur under the controlled and standardized conditions of clinical studies. Nonetheless, the in vitro data are still valuable as they allowed to discriminate between different formulations.

Evaluation of Esophageal Contraction Reserve Using HRM in Symptomatic Esophageal Disease

Esophageal high resolution manometry (HRM) is the gold standard for assessment of esophageal motor disorders, but motor responses to the standard 5 mL water swallow protocol may not provide precision in defining minor motor disorders. Provocative maneuvers, particularly multiple rapid swallows (MRS), have been used to assess deglutitive inhibition during the repetitive swallows, and the contractile response following the final swallow of the sequence. The augmentation of esophageal smooth muscle contraction following MRS is termed contraction reserve. This is determined as the ratio between esophageal body contraction vigor (distal contractile integral, DCI) following MRS to the mean DCI after single swallows, which is ≥1 in the presence of contraction reserve. Reliable assessment of contraction reserve requires the performance of 3 MRS maneuvers during HRM. Absence of contraction reserve is associated with a higher likelihood of late postfundoplication dysphagia and may correlate with higher esophageal reflux burden on ambulatory reflux monitoring. Esophageal motor responses to abdominal compression, functional lumen imaging probe (FLIP) balloon distension, and pharmacologic testing (using edrophonium and cisapride) may correlate with contraction reserve. Other provocative tests useful during HRM include rapid drink challenge, solid and viscous swallows, and standardized test meals, which are more useful in evaluation of esophageal outflow obstruction and dysphagia syndromes than in identification of contraction reserve. Provocative maneuvers have been recommended as part of routine HRM protocols, and while useful clinical information can be gleaned from these maneuvers, further research is necessary to determine the precise role of provocative testing in clinical esophagology.

Predictive PBPK modeling as a tool in the formulation of the drug candidate TMP-001

Since many drugs in the therapy scheme of multiple sclerosis (MS) are applied parenterally with significant side effects, oral treatment is the most accepted therapy option for chronic diseases like MS. The drug candidate TMP-001, which has disease-modifying properties, can be applied orally. Beside other symptoms, swallowing disorders have a major impact not only on the health status and quality of life of MS patients, but also impede reliable drug therapy. Consequently, the development of an easy-to-swallow liquid oral dosage form supported by a combined PBPK-IVIVC model was approached. In this context, the impact of formulation parameters was studied. Biorelevant in vitro drug release studies resulted in an almost complete release of 96.91% ± 1.00% in the intestine which was translated to rapidly increasing in silico plasma profiles. The predictions were compared to the outcome of a phase I clinical trial. A partial parameter sensitivity analysis of the in silico model deepened our understanding of the physiological processes underlying human pharmacokinetics.

Polymer adhesion predictions for oral dosage forms to enhance drug administration safety. Part 3: Review of in vitro and in vivo methods used to predict esophageal adhesion and transit time

The oral cavity is frequently used to administer pharmaceutical drug products. This route of administration is seen as the most accessible for the majority of patients and supports an independent therapy management. For current oral dosage forms under development, the prediction of their unintended mucoadhesive properties and esophageal transit profiles would contribute for future administration safety, as concerns regarding unintended adhesion of solid oral dosage forms (SODF) during oro-esophageal transit still remain. Different in vitro methods that access mucoadhesion of polymers and pharmaceutical preparations have been proposed over the years. The same methods might be used to test non-adhesive systems and contribute for developing safe-to-swallow technologies. Previous works have already investigated the suitability of non-animal derived in vitro methods to assess such properties. The aim of this work was to review the in vitro methodology available in the scientific literature that used animal esophageal tissue to evaluate mucoadhesion and esophageal transit of pharmaceutical preparations. Furthermore, in vivo methodology is also discussed. Since none of the in vitro methods developed are able to mimic the complex swallowing process and oro-esophageal transit, in vivo studies in humans remain as the gold standard.

Comparison of videofluoroscopy and impedance planimetry for the evaluation of oesophageal stenosis: a retrospective study

Objectives

To compare videofluoroscopy that included a tablet test with impedance planimetry (EndoFLIP^®) for the evaluation of oesophageal stenosis in patients with dysphagia.

Methods

In 56 patients, videofluoroscopic examinations following the transit of a 14-mm tablet were retrospectively reviewed and correlated with impedance planimetry findings, a catheter-based method using impedance planimetry to display the oesophageal diameter estimates. Additional findings assessed were the occurrence of symptoms during tablet passage and evaluation of oesophageal motility.

Results

Impaction of the tablet occurred in 31/56 patients; nine showed a moderate delay (2–15 s), three a short delay (<2 s) and 13 no delay of tablet passage. Both methods showed a significant correlation between tablet impaction and oesophageal diameter <15.1 mm, as measured by impedance planimetry (p = 0.035). The feeling of the tablet getting stuck was reported by seven patients, six showing impaction of the tablet (four with an EndoFLIP-diameter < 13 mm, two with a diameter of 13–19 mm) and one showing delayed passage (EndoFLIP diameter of 17 mm).

Conclusions

Videofluoroscopy and impedance planimetry correlate significantly regarding tablet impaction and residual oesophageal lumen. A standardized 14-mm tablet is helpful in demonstrating oesophageal strictures in dysphagic patients. Triggering of subjective symptoms provides valuable information during a videofluoroscopic study.

Key Points

• A 14-mm tablet can demonstrate oesophagogastric junction narrowing in patients with dysphagia.

• Type of passage of a tablet enables estimation of oesophageal luminal diameter.

• Videofluoroscopy and impedance planimetry correlate significantly regarding tablet impaction and residual oesophageal lumen.

Patient-centred pharmaceutical design to improve acceptability of medicines: similarities and differences in paediatric and geriatric populations

Patient acceptability of a medicinal product is a key aspect in the development and prescribing of medicines. Children and older adults differ in many aspects from the other age subsets of population and require particular considerations in medication acceptability. This review highlights the similarities and differences in these two age groups in relation to factors affecting acceptability of medicines. New and conventional formulations of medicines are considered regarding their appropriateness for use in children and older people. Aspects of a formulation that impact acceptability in these patient groups are discussed, including, for example, taste/smell/viscosity of a liquid and size/shape of a tablet. A better understanding of the acceptability of existing formulations highlights opportunities for the development of new and more acceptable medicines and facilitates safe and effective prescribing for the young and older populations.

Two techniques to make swallowing pills easier

To evaluate whether 2 techniques (the pop-bottle method for tablets and the lean-forward technique for capsules) ease swallowing of tablets and capsules, we conducted a cross-sectional study including 151 adults of the general German population. Participants swallowed 16 differently shaped placebos, rated their ease of swallowing on an 8-point Likert scale, and swallowed the 2 dosage forms that they had rated most difficult again using the appropriate technique. The pop-bottle method substantially improved swallowing of tablets in 59.7% (169/283) and the lean-forward technique for capsules in 88.6% (31/35). Both techniques were remarkably effective in participants with and without reported difficulties swallowing pills and should be recommended regularly.

Process analytical technology to understand the disintegration behavior of alendronate sodium tablets

Various adverse events including esophagus irritations have been reported with the use of alendronate tablets, likely attributed to the rapid tablet disintegration in the mouth or esophagus. Accordingly, the disintegration of six alendronate tablet drug products was studied using a newly developed testing device equipped with in-line sensors, in addition to the official compendial procedure for measuring the disintegration time. The in-line sensors were used to monitor the particle count and solution pH change to assess the onset and duration of disintegration. A relatively large variation was observed in the disintegration time of the tested drug products using the compendial method. The data collected using the in-line sensors suggested that all tested drug products exhibited almost instantaneous onset of disintegration, under 2 s, and a sharp drop in solution pH. The drop in pH was slower for tablets with slower disintegration. The in-house prepared alendronate test tablets also showed similar trends suggesting rapid solubilization of the drug contributed to the fast tablet disintegration. This research highlights the usefulness of the newly developed in-line analytical method in combination with the compendial method in providing a better understanding of the disintegration and the accompanying drug solubilization processes for fast disintegrating tablet drug products.

Imaging evaluation of dogs and cats with Dysphagia

The current literature is reviewed in this paper regarding the application of diagnostic imaging in the evaluation of swallowing disorders of the dog. The applications of radiography, contrast radiography, and contrast videofluoroscopy are discussed with pertinent case examples provided for emphasis. The indications for image-guided interventions are also described.

Comparison of bolus transit patterns identified by esophageal impedance to barium esophagram in patients with dysphagia

Bolus transit through the esophagus has not been validated by videoesophagram in patients with dysphagia and changes in impedance with abnormal barium transit have not been described in those patients. The aim of this study was to compare esophageal impedance findings with barium esophagram measurements in patients with dysphagia. The consecutive patients with dysphagia underwent conventional multichannel esophageal impedance manometry, after which a barium videoesophagram was performed simultaneously with multichannel esophageal impedance manometry using a mean of three swallows of barium. Esophageal emptying patterns shown in the esophagogram were classified by the degree of intraesophageal stasis and presence of intraesophageal reflux. Bolus transit patterns in impedance were classified as complete and incomplete transit. Sixteen patients (M : F = 8 : 8, mean age, 47 years) were enrolled. Their manometric diagnosis were normal (n= 6), ineffective esophageal motility (n= 1), diffuse esophageal spasm (DES; n= 2), and achalasia (n= 7). Sixty-three swallows were analyzed. According to impedance analysis, 21/22 swallows with normal barium emptying showed complete transit (96%) and 31/32 swallows with severe stasis showed incomplete transit (97%). Nine swallows with mild stasis showed either complete or incomplete transit patterns in impedance. Swallows with mild barium stasis and complete transit in impedance were observed in patients who had received treatment (two patients with achalasia with history of esophageal balloonplasty and a patient with DES after nifedipine administration). Impedance reflected severe stasis with retrograde barium movement and described typical bolus transit patterns in patients with achalasia and DES. In conclusion, impedance-barium esophagram concordance is high for swallows with normal esophageal emptying and for severe barium stasis in patients with dysphagia.

Pharmaceutical applications of AC biosusceptometry

AC Biosusceptometry offers an alternative to investigate noninvasively and without ionizing radiation the behavior of solid dosage forms in vitro and in the human gastrointestinal tract. This versatility allowed applying this technique in a wide field ranging from characterization of the disintegration process to elucidation of how the physiological parameters can interfere with pharmaceutical processes. It is increasingly important to understand how oral solid dosage forms behave in the human gastrointestinal tract. Once labelled, magnetic dosage forms provide an excellent opportunity to investigate complexes' interactions between dosage form and gastrointestinal physiology. In this paper, basic principles of this biomagnetic instrumentation and of the quantification based on magnetic images are reviewed. Also will be presented are some of the most recent applications of AC Biosusceptometry in the pharmaceutical research including oesophageal transit, gastric emptying and transit time of multiparticulate dosage forms, hydrophilic matrices and disintegration of tablets.

Effects of anatomical position on esophageal transit time: A biomagnetic diagnostic technique

AIM: To study the esophageal transit time (ETT) and compare its mean value among three anatomical inclinations of the body; and to analyze the correlation of ETT to body mass index (BMI).

METHODS: A biomagnetic technique was implemented to perform this study: (1) The transit time of a magnetic marker (MM) through the esophagus was measured using two fluxgate sensors placed over the chest of 14 healthy subjects; (2) the ETT was assessed in three anatomical positions (at upright, fowler, and supine positions; 90º, 45º and 0º, respectively).

RESULTS: ANOVA and Tuckey post-hoc tests demonstrated significant differences between ETT mean of the different positions. The ETT means were 5.2 ± 1.1 s, 6.1 ± 1.5 s, and 23.6 ± 9.2 s for 90º, 45º and 0º, respectively. Pearson correlation results were r = -0.716 and P < 0.001 by subjects’ anatomical position, and r = -0.024 and P > 0.05 according the subject’s BMI.

CONCLUSION: We demonstrated that using this biomagnetic technique, it is possible to measure the ETT and the effects of the anatomical position on the ETT.

Esophageal transit and in vivo disintegration of branded risedronate sodium tablets and two generic formulations of alendronic acid tablets: a single-center, single-blind, six-period crossover study in healthy female subjects

BACKGROUND

Delayed esophageal transit or disintegration of oral bisphosphonate tablets before they enter the stomach may be of concern with respect to iatrogenic complications among patients receiving longterm treatment. Different formulations of generic bisphosphonate tablets meeting regulatory requirements may have substantial differences in pharmaceutical attributes from the branded product that may result in different characteristics during esophageal transit.

OBJECTIVE

The primary objective of this study was to evaluate and compare esophageal transit times and in vivo disintegration of 3 bisphosphonate formulations, one branded and the others generic, that are commercially available in Canada and the United Kingdom.

METHODS

This was a single-center, randomized, singleblind, 6-period crossover study in healthy postmenopausal women aged >50 years. Each subject received a single oral dose of a branded risedronate sodium 35-mg tablet and 2 generic formulations of alendronic acid 70-mg tablets (Novopharm Limited, Toronto, Canada, and Teva UK Limited, Morley, United Kingdom) in both the erect and semisupine (45 degrees ) positions. Although the products are labeled to be taken in the erect position, the semisupine position was included to simulate dosing in bedridden patients. Subjects took tablets with 30 mL of water in the morning after an overnight fast. The tablets were radiolabeled with technetium-99m ion-exchange resins to enable visualization and measurement of esophageal transit time and disintegration using a gamma camera. Dynamic scintigraphic images were obtained for a total of 10 minutes: 2 images per second for the first 30 seconds and 1 image every 15 seconds for 9.5 minutes. This was a mechanistic study and tolerability was not assessed.

RESULTS

The study was conducted in 20 healthy white female subjects with a mean age of 62 years (range, 51-77 years). The effect of body position was statistically significant (P = 0.043), with the estimated hazard ratio (HR) of 0.74 indicating longer transit time in the semisupine position relative to the erect position. There was a statistically significant difference in transit time among the 3 types of tablets (P = 0.007), with the Novopharm tablet (HR = 0.59; P < 0.001) and Teva tablet (HR = 0.71; P = 0.042) having longer transit times compared with the risedronate tablet. In 4 instances, the Novopharm tablet disintegrated and dispersed in the esophagus, once in the erect position and 3 times in the semisupine position.

CONCLUSIONS

In these healthy female subjects, esophageal transit was delayed when the tablets were given in the semisupine position. The branded risedronate tablet had a significantly faster transit time than the 2 generic formulations of alendronate tested.