Geriatric drug delivery - barriers, current technologies and the road ahead

The geriatric population encompasses the largest part of the health care system worldwide. Chronic medical conditions are highly prevalent in the elderly, consequently, due to their complex health needs, there is a significant rate of multi-drug therapy. Despite the high numbers of medications prescribed, geriatric patients face several barriers when it comes to successful drug delivery including alterations in cognitive and physical function. The current review highlights the impact of chronic diseases on the ageing population along with how changes in drug pharmacokinetics could impact drug efficacy and safety. Also discussed are applications of administration routes in the geriatric population and complications that could arise. A focus is placed on the traditional and upcoming drug delivery advancements being employed in seniors with a focus addressing obstacles faced by this patient category. Nanomedicines, three-dimensional printing, long-acting formulations, transdermal systems, orally disintegrating tablets, and shape/taste modification technologies are discussed. Several barriers to drug delivery in the elderly have been identified in literature and directions for future studies should focus on addressing these gaps for geriatric drug formulation development including personalised medicine, insights into novel drug delivery systems like nanomedicines, methods for decreasing pill burden and shape/size modifications.ARTICLE HIGHLIGHTSTypically, senior citizens take more medications than any other patient population, yet most drug delivery technologies are not tailored to address the specific cognitive and physical barriers that these individuals encounter.The safety of drug delivery systems in the elderly patients should be prioritised with considerations on changes in pharmacokinetics with age, use of non-toxic excipients, and selecting drugs with minimal off-target side effects.Several commercialised and upcoming drug delivery technologies have begun to address the current limitations that the ageing population faces.Future research should focus on applying novel strategies like 3D printing, personalised medicine, and long-acting formulations to improve drug delivery to elderly patients.

Pharmacologic Treatment of Hypertension in Older Adults

The authors conducted a review of pharmacologic therapy in older adults with hypertension. They reviewed the evidence supporting their use in older adults, understanding the physiologic changes and potential adverse drug effects associated with aging and antihypertensive medication use, exploring guideline recommendations for antihypertensive use in older adults, and evaluating the associated risks and benefits of specific classes of antihypertensive medications.

Breaking barriers: bilosomes gel potentials to pave the way for transdermal breast cancer treatment with Tamoxifen

OBJECTIVE

Breast cancer affects women globally, regardless of age or location. On the other hand, Tamoxifen (TXN), a class II biopharmaceutical drug is acting as a prophylactic/treating agent for women at risk of and/or with hormone receptor-positive breast cancer. However, its oral administration has life-threatening side effects, which have led researchers to investigate alternative delivery methods. One such method is transdermal drug delivery utilizing bile salts as penetration enhancers, aka Bilosomes.

METHODS

Bilosomes formulations were optimized statistically for the outcome of vesicle shape, size, and entrapment efficiency using two types of bile, i.e. sodium taurocholate and sodium cholate. These bilosomes were then loaded into HPMC base gel and further characterized for their morphology, drug content, pH, viscosity, spreadability and eventually ex-vivo skin penetration and deposition studies.

RESULTS

Findings showed that sodium cholate has superiority as a penetration enhancer over sodium taurocholate in terms of morphological characterizes, zeta potential, and cumulative amounts of tamoxifen permeated per unit area (15.13 ± 0.71 μg/cm2 and 6.51 ± 0.6 μg/cm2 respectively). In fact, bilosomes designed with sodium cholate provided around 9 folds of skin deposition compared to TXN non-bilosomal gel.

CONCLUSION

Bilosomes gels could be a promising option for locally delivering tamoxifen to the breast through the skin, offering an encouraging transdermal solution.

Recent advances in dosage form design for the elderly: a review

INTRODUCTION

With the increase in the elderly population and the prevalence of multiple medical conditions, medication adherence, and efficacy have become crucial for the effective management of their health. The aging population faces unique challenges that need to be addressed through advancements in drug delivery systems and formulation technologies.

AREAS COVERED

The current review highlights the recent advances in dosage form design for older individuals, with consideration of their specific physiological and cognitive changes. Various dosage forms, such as modified-release tablets/capsules, chewable tablets, and transdermal patches, can be tailored to meet the specific needs of elderly patients. Advancements in drug delivery systems, such as nanotherapeutics, additive manufacturing (three-dimensional printing), and drug-food combinations, improve drug delivery and efficacy and overcome challenges, such as dysphagia and medication adherence.

EXPERT OPINION

Regulatory guidelines and considerations are crucial in ensuring the safe utilization of medications among older adults. Important factors to consider include geriatric-specific guidelines, safety considerations, labeling requirements, clinical trial considerations, and adherence and accessibility considerations.

Pharmacokinetics of Antibacterial Agents in the Elderly: The Body of Evidence

Infections are important factors contributing to the morbidity and mortality among elderly patients. High rates of consumption of antimicrobial agents by the elderly may result in increased risk of toxic reactions, deteriorating functions of various organs and systems and leading to the prolongation of hospital stay, admission to the intensive care unit, disability, and lethal outcome. Both safety and efficacy of antibiotics are determined by the values of their plasma concentrations, widely affected by physiologic and pathologic age-related changes specific for the elderly population. Drug absorption, distribution, metabolism, and excretion are altered in different extents depending on functional and morphological changes in the cardiovascular system, gastrointestinal tract, liver, and kidneys. Water and fat content, skeletal muscle mass, nutritional status, use of concomitant drugs are other determinants of pharmacokinetics changes observed in the elderly. The choice of a proper dosing regimen is essential to provide effective and safe antibiotic therapy in terms of attainment of certain pharmacodynamic targets. The objective of this review is to perform a structure of evidence on the age-related changes contributing to the alteration of pharmacokinetic parameters in the elderly.

Slower progression of amyotrophic lateral sclerosis with external application of a Chinese herbal plaster–The randomized, placebo-controlled triple-blinded ALS-CHEPLA trial

Background

Amyotrophic lateral sclerosis (ALS) is a chronic neurodegenerative disease characterized by gradually increasing damage to the upper and lower motor neurons. However, definitive and efficacious treatment for ALS is not available, and oral intake in ALS patients with bulbar involvement is complicated due to swallowing difficulties.

Hypothesis/purpose

This study investigated whether the external plaster application of the herbal composition Ji-Wu-Li efficiently slows ALS progression because prior studies obtained promising evidence with oral herbal applications.

Study design

The randomized, triple-blinded study compared the efficacy, safety, and tolerability of the application of Ji-Wu-Li plaster (JWLP) with placebo plaster (PLAP).

Methods

In total, 120 patients with definite ALS, clinically probable ALS, or clinically probable laboratory-supported ALS were randomized in a 1:1 ratio to receive JWLP or PLAP. Patients were treated and observed for 20 weeks. The primary outcome was the ALSFRS-R score, while the secondary outcomes were the ALS-SSIT score and weight loss.

Results

The mean±SD decrease in the ALSFRS-R over 20 weeks differed by 0.84 points in a group comparison (JWLP, −4.44 ± 1.15; PLAP, −5.28 ± 1.98; p = 0.005). The mean increase in the ALS-SSIT over 20 weeks differed by 2.7 points in a group comparison (JWLP, 5.361.15; PLAP, 8.06 ± 1.72; p < 0.001). The mean weight loss over 20 weeks differed by 1.65 kg in a group comparison (JWLP, −3.98 ± 2.61; PLAP, −5.63 ± 3.17; p = 0.002). Local allergic dermatitis suspected as causal to the intervention occurred in 10 of 60 participants in the JWLP group and 9 of 60 participants in the PLAP group. Systemic adverse events were mild, temporary, and considered unrelated to the intervention.

Conclusion

The JWLP showed clinical efficacy in the progression of ALS, as measured by the ALSFRS-R, ALS-SSIT, and weight loss in a randomized, placebo-controlled trial. Because skin reactions occurred in both groups, the covering material needs improvement. All of the Ji Wu Li herbal ingredients regulate multiple mechanisms of neurodegeneration in ALS. Hence, JWLP may offer a promising and safe add-on therapy for ALS, particularly in patients with bulbar involvement, but a confirmative long-term multicentre study is required.

Bioavailability Study of a Transdermal Patch Formulation of Rivastigmine Compared with Exelon in Healthy Subjects

BACKGROUND AND OBJECTIVES

Rivastigmine is a reversible cholinesterase inhibitor indicated for the treatment of all stages of Alzheimer's disease (AD). Transdermal patch formulation allows smooth and continuous drug delivery. Its tolerability, efficacy and convenience of use increase treatment compliance. This study was designed to evaluate the bioavailability and to assess the bioequivalence of two rivastigmine transdermal patches at steady state (RIV-TDS Test Product versus Exelon Marketed Reference Product), with a release rate of 13.3 mg/24 h, after multiple patch applications. As secondary objectives, safety, patch adhesion and skin irritation were evaluated.

METHODS

This was an open-label, randomized, balanced, two-period, two-sequence, cross-over study of healthy adults (n = 31). The treatment period consisted of two 5-day study periods during which consecutive daily application of the investigational patches with a release rate of 13.3 mg/24 h rivastigmine took place. Serial blood samples were collected to measure plasma concentrations. Adhesion and skin irritation assessments were performed after application of patches.

RESULTS

Point estimates and 90% confidence intervals of pharmacokinetic parameters at steady state, viz. area under the plasma concentration versus time curve from dosing time to the end of the dosing interval τ (profile day) at steady state [AUC_0-τ,ss] (97.4; 88.8-106.9), maximum plasma concentration within the dosing interval τ (profile day) at steady state [C_max,ss] (99.6; 90.4-109.7) and trough plasma concentration at the end of the dosing interval τ (profile day) at steady state [C_τ,ss] (96.8; 86.2-108.9), demonstrated that both patches were bioequivalent. Evaluation of patch adhesion showed better skin adherence for RIV-TDS as well as dermal response scores (skin tolerability after removal).

CONCLUSIONS

For both products, bioequivalence was shown and systemic tolerability was in accordance with the safety profile of the drug substance. The trial is registered in ClinicalTrials.gov: NCT03573050 and EudraCT: 2018-000968-28.

Biochemical, structural and physical changes in aging human skin, and their relationship

Skin is the largest organ of the human body, having the purpose of regulating temperature, protecting us from microbes or mechanical shocks, and allowing the sensations from touch. It is generally accepted that aging induces profound changes in the skin's biochemical, structural and physical properties, which can lead to impaired biological functions and/or diverse diseases. So far, the effects of aging on these skin properties have been well documented. However, very few studies have focused exclusively on the relationship among these critical properties in the aging process, which is this review's primary focus. Many in vivo, ex vivo, and in vitro techniques have been previously used to characterize these properties of the skin. This review aims to provide a comprehensive overview on the effects of aging on the changes in biochemical, structural, and physical properties, and explore the potential mechanisms of skin with the relation between these properties. First, we review different or contradictory results of aging-related changes in representative parameters of each property, including the interpretations of the findings. Next, we discuss the need for a standardized method to characterize aging-related changes in these properties, to improve the way of defining age-property relationship. Moreover, potential mechanisms based on the previous results are explored by linking the biochemical, structural, and physical properties. Finally, the need to study changes of various functional properties in the separate skin layers is addressed. This review can help understand the underlying mechanism of aging-related alterations, to improve the evaluation of the aging process and guide effective treatment strategies for aging-related diseases.

Evaluation of Metformin Hydrochloride Tailoring Bilosomes as an Effective Transdermal Nanocarrier

Introduction

Metformin hydrochloride (metformin HCL), a first-line drug treating diabetes type II, was known to cause severe gastritis, so seeking a non-oral dosage form was the new trend. Bilosomes are bilayer nano-vesicles of non-ionic surfactants embodying bile salts. In our study, bilosomes were investigated as an acceptable novel carrier for active targeting transdermal delivery of metformin HCL, circumventing its side effects.

Methods

Twelve bilosome formulations were prepared with solvent evaporation method with slight modification according to a 3¹.2² full factorial design, and the optimized formulation was determined using Design -Expert 13 software (Stat-Ease, Inc., Minneapolis, Minnesota, USA) studying the effect of surfactant and bile salt types on the entrapment efficiency (EE), vesicle size (VS), polydispersity index (PDI), zeta potential (ZP), percentage of drug released within 24 h (R), and flux of drug permeated within 6 h (Jss) of vesicles. In addition, the optimized formulation was further evaluated to Fourier-transform infrared spectroscopy (FTIR), deformability index (DI), and transmission electron microscope (TEM) to ensure bilosomes formation, elasticity, and spherical shape, respectively.

Results

The resulting vesicles publicized EE from 56.21% to 94.21%, VS from 183.64 to 701.8 nm, PDI values oscillating between 0.33 and 0.53, ZP (absolute value) from 29 to 44.2 mV, biphasic release profile within 24 h from 60.62 and up to 75.28%, and permeation flux enhancement (198.79–431.91 ng cm ⁻² h⁻¹) in comparison with the non-formulated drug (154.26 ng cm ⁻² h⁻¹). Optimized formulation was found to be F8 with EE = 79.49%, VS = 237.68 nm, ZP = 40.9 mV, PDI = 0.325, R = 75.28%, Jss = 333.45 ng cm⁻² h⁻¹ and DI = 6.5 with spherical self-closed non-aggregated vesicles and non-superimposed bands of its components in the FTIR.

Conclusion

Overall results showed that bilosome incorporation of metformin HCL improved permeation and offered a new nano-carrier for active transdermal delivery.

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Nonopioid Analgesics for the Perioperative Geriatric Patient: A Narrative Review

Management of acute perioperative pain in the geriatric patient can be challenging as the physiologic and pharmacokinetic changes associated with aging may predispose older patients to opioid-related side effects. Furthermore, elderly adults are more susceptible to postoperative delirium and postoperative cognitive dysfunction, which may be exacerbated by both poorly controlled postoperative pain and commonly used pain medications. This narrative review summarizes the literature published in the past 10 years for several nonopioid analgesics commonly prescribed to the geriatric patient in the perioperative period. Nonopioid analgesics are broken down as follows: medications prescribed throughout the perioperative period (acetaminophen and nonsteroidal anti-inflammatory drugs), medications limited to the acute perioperative setting (N-methyl-D-aspartate receptor antagonists, dexmedetomidine, dexamethasone, and local anesthetics), and medications to be used with caution in the geriatric patient population (gabapentinoids and muscle relaxants). Our search identified 1757 citations, but only 33 specifically focused on geriatric analgesia. Of these, only 21 were randomized clinical trials' and 1 was a systematic review. While guidance in tailoring pain regimens that focus on the use of nonopioid medications in the geriatric patient is lacking, we summarize the current literature and highlight that some nonopioid medications may extend benefits to the geriatric patient beyond analgesia.

Comparative Bioavailability Study of a Novel Multi-Day Patch Formulation of Rivastigmine (Twice Weekly) with Exelon® Transdermal Patch (Daily)- A Randomized Clinical Trial

BACKGROUND

Rivastigmine, a reversible AChEI for symptomatic treatment of mild to moderately severe Alzheimer's dementia, is administered once daily transdermal patches, enabling an easier and continuous drug delivery. A novel multi-day (twice week) patch formulation was developed with greater convenience for patients' therapeutic management.

OBJECTIVE

To assess the bioequivalence under SS conditions of the multiple-day rivastigmine transdermal patch (Test Product, RID-TDS) in comparison to the once-daily Exelon® transdermal patch (Reference Product), both at a release rate of 9.5 mg/24 h.

DESIGN

Single-center, open-label, randomized, multiple-dose study in healthy male adults in a 2- period, 2-sequence-crossover design with multiple applications.

METHODS

Patches were applied on 11 consecutive days for Exelon® and a 4-3-4-day regimen for the multiday test patch (RID-TDS), separated by a 14-day wash-out period. The safety, local tolerability and inhibitory effect of rivastigmine on plasma BuChE activity were also evaluated.

RESULTS

57 subjects completed the study according to the protocol. Calculated point estimates and 90% CI for all primary parameters (AUC96-264, Cmax96-264 and Cmin96-264) were within the predefined acceptance interval of 80.00-125.00%. They were 113.64% (107.33-120.33), 105.14% (98.38- 112.38) and 107.82% (97.78-118.89) respectively. Satisfactory adhesion (CI of mean adhesion above 90%) was demonstrated for RID-TDS but not for Exelon®.

CONCLUSION

Bioequivalence was demonstrated between RID-TDS mg twice a week and Exelon® once daily in SS. Patch adhesion favored RID-TDS despite the longer dosing interval. Both products were well tolerated.

Recent advances in polymeric transdermal drug delivery systems

Transdermal delivery has proven to be one of the most favorable methods among novel drug delivery systems. Since drugs administered by transdermal delivery systems avoid the gastrointestinal tract, and thus avoid conversion by the liver, the likelihood of liver dysfunction and gastrointestinal tract irritation as side effects is low. Drug delivery through the skin has other advantages, such as maintaining an effective rate of drug delivery over time, a steady rate of circulation, and the benefits of a passive delivery system and diffusion. Transdermal drug delivery is achieved using patches which consist of different and specific layers. In the last few decades, many types of patches have been approved worldwide, such as medical plasters, which have been generally applied to the skin for localized diseases. Such patches can be traced back to ancient China (around 2000 BCE) and are the early precursors of today's transdermal patches. With the help of effective design, materials, manufacturing, and evaluation, a large number of drugs can now be administered using this valuable advanced technology. This study reviews different types of polymer patches, their advantages and disadvantages, and different studies related to transdermal drug delivery methods, and the advantages and disadvantages of each method. Different mechanisms of transdermal drug delivery system with patches are also discussed.

Allopurinol Loaded Transferosomes for the Alleviation of Symptomatic After-effects of Gout: An Account of Pharmaceutical Implications

Background:

The present study assessed the transdermal potential of transferosomes loaded with allopurinol for the treatment of gout.

Methods:

Transferosomes of allopurinol were composed of different ratios of tween-80, soya lecithin and solvent using a thin-film hydration method. Transferosomes were characterized for Scanning Electron Microscopy (SEM), zeta potential, % entrapment efficiency (%EE), Fourier Transform Infrared Spectroscopy (FTIR), in-vitro drug release and kinetics as well as stability. Then, optimized formulation was incorporated in gel and evaluated for viscosity, pH, extrudability, homogeneity, skin irritation study, spreadability, ex vivo skin permeation study, flux, and stability.

Results:

SEM studies suggested that vesicles were spherical and zeta potential were in the range of -11.4 mV to -29.6 mV and %EE was 52.4- 83.87%. FTIR study revealed that there was no interaction between allopurinol and excipients during the preparation of transferosomes. The cumulative percentage of drug release from various transferosomes was ranged from 51.87 to 81.87%. A transferosomal gel of F8 formulation was prepared using dispersion method reported pseudoplastic rheological behavior, optimum pH, spreadability and maximum drug permeation i.e. 79.84% with flux 13.06 g/cm2/hr, followed zero-order release kinetics. Irritation and in-vivo studies of optimized transferosomal gel G8 on rabbits revealed better results than the standard allopurinol.

Conclusion:

This research suggested that allopurinol loaded transferosomal gel can be potentially used as a transdermal drug delivery system for the treatment of gout.

Prescribing medicines to older people-How to consider the impact of ageing on human organ and body functions

Ageing is associated with several changes in human organs, which result in altered medication pharmacokinetics and pharmacodynamics. Ageing is also associated with changes in human body functions, such as impaired vision, hearing, swallowing, motor and cognitive functions, which can affect the adequate intake and administration of drugs. As a consequence, older people, and especially patients older than 75 years, are the main users of many drugs and they frequently use 5 drugs or more long-term (i.e. polypharmacy). All this increases the complexity of adequate drug intake, administration and adherence. However, there is a lack of evidence on the considerations that should be taken into account to ensure appropriate drug prescribing to older people. This review article summarizes the most clinically relevant changes in human organ and body functions and the consequential changes in pharmacokinetics and pharmacodynamics in older people, along with possible dosing consequences or alternatives for drugs frequently prescribed to this patient population. Recommendations are given on how ageing could be considered in clinical drug development, drug authorization and appropriate prescribing.

Novel Design Approaches in the Fabrication of Polymeric Microarray Patches via Micromoulding

The focus on novel systems for transdermal delivery of therapeutic agents has increased considerably over recent years, as this administration route comes with many advantages. Polymeric microarray patches (MAPs) are minimally invasive devices that enable systemic delivery of a wide range of drugs by overcoming the outer skin barrier. Conventionally, MAPs fabricated by micromoulding have a low needle density. In this study, the performance of hydrogel-forming MAPs cast using novel industrially manufactured micromoulds with a high needle density (600 needles/0.75 cm²) was compared to that of MAPs obtained using conventional moulds with a lower density (196 needles/0.89 cm²). Surrounding holders for micromoulds were designed for time-efficient fabrication of MAPs. The influence of needle densities on mechanical strength, insertion efficiency and in vitro permeation of ibuprofen sodium (IBU) was analysed. Insertion of both MAPs into an artificial skin model and neonatal porcine skin was comparable. No significant difference was observed in permeation studies of IBU (p > 0.05), with a delivery of 8.7 ± 1.7 mg for low-density and 9.5 ± 0.1 mg for high-density MAPs within 24 h. This highlights the potential of these novel micromoulds for manufacturing polymeric MAPs with a higher needle density for future applications.

Biopolymer Substrates in Buccal Drug Delivery: Current Status and Future Trend

BACKGROUND

This paper provides a critical review of biopolymer-based substrates, especially the cellulose derivatives, for their application in buccal drug delivery. Drug delivery to the buccal mucous has the benefits of immobile muscle, abundant vascularization and rapid recovery, but not all the drugs can be administered through the buccal mucosa (e.g., macromolecular drugs), due to the low bioavailability caused by their large molecular size. This shortfall inspired the rapid development of drug-compounding technologies and the corresponding usage of biopolymer substrates.

METHODS

Cellulose derivatives have been extensively developed for drug manufacturing to facilitate its delivery. We engaged in structured research of cellulose-based drug compounding technologies. We summarized the characteristic cellulose derivatives which have been used as the biocompatible substrates in buccal delivery systems. The discussion of potential use of the rapidly-developed nanocellulose (NC) is also notable in this paper.

RESULTS

Seventy-eight papers were referenced in this perspective paper with the majority (sixty-five) published later than 2010. Forty-seven papers defined the buccal drug delivery systems and their substrates. Fifteen papers outlined the properties and applications of cellulose derivatives. Nanocellulose was introduced as a leading edge of nanomaterial with sixteen papers highlighted its adaptability in drug compounding for buccal delivery.

CONCLUSION

The findings of this perspective paper proposed the potential use of cellulose derivatives, the typical kind of biopolymers, in the buccal drug delivery system for promoting the bioavailability of macromolecular drugs. Nanocellulose (NC) in particular was proposed as an innovative bio-binder/carrier for the controlled-release of drugs in buccal system.

Psychopharmacology and pharmacokinetics

The overall physiologic changes associated with aging lead to changes in both pharmacokinetic and pharmacodynamic actions of many medications. This, in turn, leads to changes in the impact that a wide variety of medications have on older adults when compared to younger, healthy individuals. These pharmacokinetic and pharmacodynamic variations can cause either lesser or greater than expected responses to medication. Knowledge of the physiologic changes that are expected to occur in the elderly can help to identify medications that may require dose adjustments or that should be avoided, due to increased risk in this population. As a general principle, medications should be started at lower doses in the elderly with slow titration schedules to reduce the risk of adverse effects.

In vivo and qualitative studies investigating the translational potential of microneedles for use in the older population

Microneedles (MNs) are a novel transdermal drug delivery platform, rapidly progressing from a substantive evidence base, towards commercialisation. As part of this transition, it is important to consider the future use of MNs by older people in order to ensure optimal therapeutic outcomes for this unique and increasing population group. This paper, therefore, considers the use of MNs by those aged over 65 years, investigating insertion parameters in ageing skin, alongside the feasibility and acceptability of the technology. Hydrogel-forming MN arrays were applied to seven subjects aged over 65 years, with breach of the stratum corneum confirmed using optical coherence tomography. Insertion depths recorded in each case were similar to a comparative group, aged 20–30 years. Skin recovery was, however, demonstrated to occur at a slower rate in the older subjects, as measured using transepidermal water loss. Qualitative methods, including focus groups and semi-structured interviews, were employed to collect the views and opinions of older people and community pharmacists respectively. The overall consensus was positive, with a number of benefits to MN-mediated drug delivery identified, such as reduced dosing frequency, improved adherence and an alternative delivery route where oral or injectable medication was precluded. Concerns centred on practical issues associated with age-related functional decline, including, for example, reduced dexterity and skin changes. The presentation of this work collectively provides the first convincing report of the importance of further translational research in this area to support future MN use in older people, ensuring an age-appropriate delivery platform.

Challenges and innovations of drug delivery in older age

Both drug delivery performance and various age-related physical, mental and physiological changes can affect drug effectiveness and safety in elderly patients. The many drug delivery systems developed over the years include recent novel transdermal, nasal, pulmonary and orally disintegrating tablets that provide consistent, precise, timely and more targeted drug delivery. Certain drug delivery systems may be associated with suboptimal outcomes in the elderly because of the nature of drug present, a lack of appreciation of the impact of age-related changes in drug absorption, distribution and clearance, the limited availability of pharmacokinetic, safety and clinical data. Polypharmacy, patient morbidity and poor adherence can also contribute to sub-optimal drug delivery systems outcomes in the elderly. The development of drug delivery systems for the elderly is a poorly realised opportunity, with each system having specific advantages and limitations. A key challenge is to provide the innovation that best meets the specific physiological, psychological and multiple drug requirements of individual elderly patients.

Development of Drug-in-Adhesive Patch with a Honeycomb Film as a Backing Layer

Excess stripping of stratum corneum (SC) layers by patch-peeling from the skin surface is one cause of skin irritation. High SC hydration by patch occlusion may also cause skin irritation, although the occlusive technique is preferable to increase the skin permeation of topically applied drugs. In the present study, film having a honeycomb structure was selected as the backing layer of a drug-in-adhesive (DIA) patch to reduce peeling of the SC without losing adhesion force to the skin surface, as well as decreasing the skin permeation of a model drug, tulobuterol. The usefulness of the DIA patch with honeycomb film was evaluated by transepidermal water loss (TEWL) changes, amount of SC removed by patch-peeling, distribution pattern of removed SC on the adhesive layer, and water permeation through the patch. Furthermore, skin permeation and release profiles of tulobuterol from the DIA patch were investigated. Significantly (p<0.05) less TEWL change was observed after removal of the patch with a honeycomb film compared with the conventional pressure-sensitive adhesive patch, and no difference in tulobuterol permeation through skin from the patches was confirmed regardless of the type of backing layer. In addition, a lower amount of SC was removed by the peeling of the patch with a honeycomb film. The results suggest that DIA patches with a honeycomb film as a backing layer may be used to achieve less SC removal without reducing the skin permeation of drugs.

Therapeutic challenges in the mature patient

With the tremendous increase in the proportion of seniors in the global population, geriatric health care has become of greater interest and concern. Increased emphasis on geriatric medicine, along with the growth in the development of age-related skin disorders, has led to particular attention for geriatric, dermatology and dermatopharmacology. An aging population has brought many therapeutic challenges that we need to recognize and overcome by applying geropharmacologic principles. The purpose of this paper is to inform dermatologists of the age-related changes in the pharmacokinetics of common dermatologic drugs, their various interactions potentially occurring in the elderly, and the principles and evidence-based strategies for detection, management, and prevention to improve medication adherence. By implementing these principles and strategies, we can ensure the best and the safest treatment to promote the desired therapeutic outcome and improved quality of life for this fragile subpopulation.

Pharmacotherapies in Geriatric Chronic Pain Management

Pharmacologic management of chronic pain in older adults is one component of the multimodal, interdisciplinary management of this complex condition. In this article, we summarize several of the key barriers to effective pharmacologic management in older adults and review the existing (albeit limited) evidence for its effectiveness and safety, especially in a medically complex population with multimorbidity. This review covers topical formulations, acetaminophen, oral nonsteroidal antiinflammatory drugs, and adjuvant therapies. The article concludes with a suggested approach to managing chronic pain in the older patient, incorporating goals and expectations for treatment as well as careful monitoring of medication adjustments.

Regulatory development of geriatric medicines: To GIP or not to GIP?

Geriatric patients represent the main users of medicines, but are historically often minimally included in clinical trials, resulting in a gap in the knowledge of the benefit/risk balance of medicines in this heterogeneous population. As the worldwide population is aging, the need for safe and effective medicines for older patients is proportionally increasing. The aim of this review is to provide an overview of the current regulatory status of the development of geriatric medicines, the encountered challenges and the view of the involved stakeholders, coming to the conclusion whether it is necessary or not to implement a Geriatric Investigation Plan (GIP), by analogy with pediatrics.

Microneedle Coating Techniques for Transdermal Drug Delivery

Drug administration via the transdermal route is an evolving field that provides an alternative to oral and parenteral routes of therapy. Several microneedle (MN) based approaches have been developed. Among these, coated MNs (typically where drug is deposited on MN tips) are a minimally invasive method to deliver drugs and vaccines through the skin. In this review, we describe several processes to coat MNs. These include dip coating, gas jet drying, spray coating, electrohydrodynamic atomisation (EHDA) based processes and piezoelectric inkjet printing. Examples of process mechanisms, conditions and tested formulations are provided. As these processes are independent techniques, modifications to facilitate MN coatings are elucidated. In summary, the outcomes and potential value for each technique provides opportunities to overcome formulation or dosage form limitations. While there are significant developments in solid degradable MNs, coated MNs (through the various techniques described) have potential to be utilized in personalized drug delivery via controlled deposition onto MN templates.

Discontinued dermatological drugs in 2014

INTRODUCTION

Dermatology is a relatively small field concerned with conditions of the hair, skin, nails and their related diseases; yet there is considerable active research and development within the field. Pharmaceutical companies seek more effective treatments through various therapeutic classes and delivery routes. However, 28 drugs have been discontinued for the treatment of dermatologic diseases in 2014.

AREAS COVERED

Herein, the authors summarize the details about each discontinued drug in 2014. The dermatological conditions covered are: psoriasis, eczema, leg ulcers, wounds, allergies, acne, scleroderma, lupus erythematosus, urticaria, mastocytosis, epidermolysis bullosa, onychomycosis and one other unspecified disease. The authors also provide suggestions for improving and accelerating the future of dermatological drug development.

EXPERT OPINION

It is clear that improved metrics, especially for early assessment, emphasizing clinical relevance, are necessary to increase success rate. Transparency and clear communication within the field is necessary to reduce and salvage the waste that accumulates from these costly studies. Focused attention on how preclinical and early clinical studies failed to indicate subsequent toxicity profiles in patients would accelerate drug development. Distinguishing between disappointing study results and business/financial factors is important when analyzing discontinuations. A reformed approach toward study design would aid both. Ultimately, relevance and practicality for the patient must be kept in mind at all times.

Non-opiate pharmacotherapy options for the management of pain in older adults

Pain is highly prevalent, costly, and disabling in later life, especially when undertreated. In this article, we aim to describe the risks and benefits of non-opioid medication options for the management of pain in adults aged 65 years and older in order to provide additional options in a practitioner's tool box when designing a pain management regimen for an older adult. Non-opiate pharmacologic therapies, such as acetaminophen, nonsteroidal anti-inflammatory drugs, topicals, and antidepressants have an important role in pain management of older adults. When designing a pain regimen, taking an individualized approach that considers the patient's functional status, comorbidities, and treatment goals will maximize pain management.

Risk of pneumonia in new users of cholinesterase inhibitors for dementia

OBJECTIVES

To compare the risk of pneumonia in older adults receiving donepezil, galantamine, or rivastigmine for dementia.

DESIGN

Retrospective cohort study.

SETTING

Nationally representative 5% sample of Medicare databases.

PARTICIPANTS

Medicare beneficiaries aged 65 and older who newly initiated cholinesterase inhibitor therapy between 2006 and 2009.

MEASUREMENTS

Pneumonia, defined as the presence of a diagnosis code for pneumonia as the primary diagnosis on an inpatient claim or on an emergency department claim followed by dispensing of appropriate antibiotics. Cox proportional hazards models were used to estimate the risk of pneumonia. Subgroup analyses and sensitivity analyses were conducted using alternative pneumonia definitions and adjustments using high-dimensional propensity scores to test the robustness of the results.

RESULTS

The mean age of 35,570 new users of cholinesterase inhibitors (30,174 users of donepezil, 1,176 users of galantamine, 4,220 users of rivastigmine) was 82; 75% were women, and 82% were white. The cumulative incidence of pneumonia was 51.9 per 1,000 person-years. The risk of pneumonia for rivastigmine users was 24% lower than that of donepezil users (hazard ratio (HR)=0.75, 95% confidence interval (CI)=0.60-0.93). Risk in galantamine users (HR=0.87, 95% CI=0.62-1.23) was not significantly different from risk in donepezil users. Results of subgroup and sensitivity analyses were similar to the primary results.

CONCLUSION

The risk of pneumonia was lower in individuals receiving rivastigmine than in those receiving donepezil. Additional studies are needed to confirm the findings of pneumonia risk between the oral and transdermal forms of rivastigmine and in users of galantamine.

A randomized, controlled cross-over trial of dermally-applied lavender (Lavandula angustifolia) oil as a treatment of agitated behaviour in dementia

BACKGROUND

Lavender essential oil shows evidence of sedative properties in neurophysiological and animal studies but clinical trials of its effectiveness as a treatment of agitation in people with dementia have shown mixed results. Study methods have varied widely, however, making comparisons hazardous. To help remedy previous methodological shortcomings, we delivered high grade lavender oil in specified amounts to nursing home residents whose agitated behaviours were recorded objectively.

METHODS

64 nursing home residents with frequent physically agitated behaviours were entered into a randomized, single-blind cross-over trial of dermally-applied, neurophysiologically active, high purity 30% lavender oil versus an inactive control oil. A blinded observer counted the presence or absence of target behaviours and rated participants' predominant affect during each minute for 30 minutes prior to exposure and for 60 minutes afterwards.

RESULTS

Lavender oil did not prove superior to the control oil in reducing the frequency of physically agitated behaviours or in improving participants' affect.

CONCLUSIONS

Studies of essential oils are constrained by their variable formulations and uncertain pharmacokinetics and so optimal dosing and delivery regimens remain speculative. Notwithstanding this, topically delivered, high strength, pure lavender oil had no discernible effect on affect and behaviour in a well-defined clinical sample.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry (ACTRN 12609000569202).

Chronological age affects the permeation of fentanyl through human skin in vitro

AIM

To study the influence of chronological age on fentanyl permeation through human skin in vitro using static diffusion cells. Elderly individuals are known to be more sensitive to opioids and obtain higher plasma concentrations following dermal application of fentanyl compared to younger individuals. The influence of age - as an isolated pharmacokinetic term - on the absorption of fentanyl has not been previously studied.

METHOD

Human skin from 30 female donors was mounted in static diffusion cells, and samples were collected during 48 h. Donors were divided into three age groups: <30 years of age (n = 6), ≥30 and <60 years of age (n = 18) and ≥60 years of age (n = 6).

RESULTS

The youngest group had a significantly higher mean absorption (3,100 ng/cm(2)) than the two other groups (2,000 and 1,475 ng/cm(2), respectively) and a significant larger AUC (young age group: 9,393 ng; middle and old age groups: 5,922 and 4,050 ng, respectively). Furthermore, the lag time and absorption rate were different between the three groups, with a significantly higher rate in the young participants versus the oldest participants.

CONCLUSION

We demonstrate that fentanyl permeates the skin of young individuals in greater amounts and at a higher absorption rate than in middle-aged and old individuals in vitro.

A simple liquid chromatography-tandem mass spectrometry method for determination of plasma fentanyl concentration in rats and patients with cancer pain

A fentanyl patch is widely used for the treatment of cancer pain. Its few adverse effects include constipation and drowsiness. The absorption volume of transdermally applied fentanyl may differ according to its site of application and variability in patch adhesion. Since fentanyl is predominantly metabolized by the drug-metabolizing enzyme cytochrome P450 (CYP) 3A4 in the liver, its concentration may vary in cases of physiologically reduced CYP3A4 activity in the liver (liver disease and aging) or on co-administration of drugs. The clinical significance of measuring plasma concentration of fentanyl is high, but conventional methods require complicated processes such as solid-phase extraction and liquid-liquid extraction before the sample is injected into an HPLC system. In this study, a simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for determining plasma fentanyl concentrations by deproteinization with acetonitrile. A recovery test was conducted using an absolute calibration curve to confirm the method's linearity and inter- and intra-day reproducibility. The required plasma volume for detection was reduced from 1 mL in the conventional method to 20 µL in the present study, and a good calibration curve was obtained in the concentration range from 0.05 to 5 ng/mL. These findings suggest that the method for sample preparation and quantification developed in this study are appropriate for measuring fentanyl concentration in human plasma in clinical settings.

Ion-exchange and iontophoresis-controlled delivery of apomorphine

The objective of this study was to test a drug delivery system that combines iontophoresis and cation-exchange fibers as drug matrices for the controlled transdermal delivery of antiparkinsonian drug apomorphine. Positively charged apomorphine was bound to the ion-exchange groups of the cation-exchange fibers until it was released by mobile counter-ions in the external solution. The release of the drug was controlled by modifying either the fiber type or the ionic composition of the external solution. Due to high affinity of apomorphine toward the ion-exchanger, a clear reduction in the in vitro transdermal fluxes from the fibers was observed compared to the respective fluxes from apomorphine solutions. Changes in the ionic composition of the donor formulations affected both the release and iontophoretic flux of the drug. Upon the application of higher co-ion concentrations or co-ions of higher valence in the donor formulation, the release from the fibers was enhanced, but the iontophoretic steady-state flux was decreased. Overall, the present study has demonstrated a promising approach using ion-exchange fibers for controlling the release and iontophoretic transdermal delivery of apomorphine.

Low-dose 7-day transdermal buprenorphine in daily clinical practice - perceptions of elderly patients with moderate non-malignant chronic pain

OBJECTIVE

To assess patients' perceptions regarding the low-dose 7-day buprenorphine transdermal patch for treatment of moderate non-malignant chronic pain.

METHODS

Patient-reported outcome data were collected in clinical practices in Germany in a prospective, multicenter, non-interventional observation using the German Pain Questionnaire/German Pain Diary. Questionnaires were completed by the patients without influence from the attending physician. Mean change in pain intensity (lowest, average, and highest pain intensity in the previous 24 h), changes in Hospital Anxiety and Depression Scale scores (HADS-A and HADS-D), in impairments of daily activities (modified pain disability index, mPDI), in quality of life (quality of life impairment by pain inventory, QLIP), and in overall burden of pain over a 12-week treatment period were evaluated.

RESULTS

Data of 891 patients were assessed (mean age 72.8 years). Buprenorphine starting doses were mainly 5 µg/h (67.1% of patients) and 10 µg/h (27.3%). At the end of week 12, the majority received either 5 µg/h (41%) or 10 µg/h (42.3%) buprenorphine. Mean average pain intensity was reduced by 5.1 points to 1.7 ± 1.3 from 6.8 ± 1.5 points at baseline (76% improvement). Amelioration was observed in HADS-A (59% from 7.8 ± 3.3 at baseline) and HADS-D (56% from 9.2 ± 3.1), in mPDI sum score (76%; from 31.1 ± 9.8), and in quality of life (165%; from 13.9 ± 10.1). Mean burden of pain continuously decreased.

LIMITATIONS

All those inherent in open-label observations and pain studies using subjective and patient-reported outcome parameters (such as the lack of a control group).

CONCLUSIONS

Our results indicate that the 7-day buprenorphine patch might be considered an effective treatment option for moderate non-malignant chronic pain management in daily clinical practice. The mostly elderly patient population of this patient survey experienced sustained pain relief and improvements in pain-related impairments of daily activities and quality of life, leading to a substantial reduction in overall burden of pain.

Pharmacokinetics and pharmacodynamic changes associated with aging and implications for drug therapy

The population of older adults continues to increase, and polypharmacy in this population is more the rule than the exception. Physiologic changes that occur with aging result in multiple alterations to the pharmacokinetics and pharmacodynamics of drugs, which, in turn, increase the risk of adverse drug reactions. Consideration of initial dose adjustment, along with frequent medication reconciliation and analysis of the medication list, are keys to providing optimal pharmaceutical care for elderly patients.

Pharmacokinetics of transdermal buprenorphine patch in the elderly

PURPOSE

Transdermal buprenorphine patches provide comparable pain relief to that of low-potency opioids in elderly individuals. However, specific data on their use in elderly individuals is limited. This study investigated and compared the PK of buprenorphine transdermal patches in elderly (≥ 75 years) versus younger (50-60 years) individuals.

METHODS

This was a multiple-dose, open-label, parallel-group study in healthy volunteers split into two age groups (younger, 50-60 years; elderly, ≥ 75 years) with 37 individuals in each. Study participants received two consecutive 7-day buprenorphine 5 μg/h transdermal patch applications, and blood samples were collected on the week of the second patch application [day 7 (predose), days 8, 9, 10, 12, and 14] to determine PK at steady state. Pharmacokinetic parameters were determined for buprenorphine and norbuprenorphine. Safety was assessed by analyzing adverse events, hematology, clinical chemistry, urine analysis, vital signs, electrocardiogram (ECG), and physical examinations.

RESULTS

The area under the plasma concentration-time curve at steady state (AUC(tau)), measured over one dosing interval, was similar for elderly [mean ± standard deviation (SD) 9,940 pg/h/ml (4,827 pg/h/ml] and younger [mean ± SD 11,309 (3,670 pg/h/ml] individuals. Bioequivalence was not demonstrated between groups, which may be attributable to the relatively high level of variability in individual plasma profiles. More adverse events were reported by younger (216) than elderly (164) study participants.

CONCLUSIONS

No dosage alterations are necessary for PK reasons when treating elderly people with buprenorphine transdermal patches.

Irritant contact dermatitis: effect of age

Knowledge on age-relationship to irritant contact dermatitis (ICD) remains of interest. We searched for articles and textbooks on age-relationship to ICD and evaluated relevant data. Irritant response may be enhanced in children and decline with increasing age. In general, older skin reacts more slowly and with less intensity to irritants when compared with young skin. Such age-related changes may depend: (i) on differences in percutaneous penetration in old and young skin, and/or on (ii) differences in the microcirculatory efficiency, which serves as the route by which inflammatory cells make their way to the site of inflammation. Additionally, stratum corneum turnover time increases with age which means that an irritant remains longer on the skin; a compromised cutaneous blood vessel network with ageing may lead to a decreased inflammatory response, decreased absorption and decreased clearance. In conclusion, age-related differences of ICD are present despite some conflicting data. Investigations elucidating this interesting subject may benefit in prevention and intervention strategies.

Pharmacokinetics of a granisetron transdermal system for the treatment of chemotherapy-induced nausea and vomiting

Objective. To determine the pharmacokinetic (PK) profile of granisetron transdermal formulation and examine its possible relationship with age, gender, and renal function.

Methods. This article describes a Phase I PK study and a post hoc pooled population PK analysis. The Phase I study was a randomized, cross-over study that assessed PK parameters of three granisetron patch sizes and oral granisetron. The pooled population PK analysis included data from three trials in healthy subjects (n = 48) and from Phase II and III studies in patients with cancer (n = 793). The population PK model was used to investigate granisetron exposure and its possible relationship with age, gender, and renal function.

Results. Following oral dosing, plasma granisetron concentration was quantifiable at 1 h, and maximal mean concentration (4.7 ng/mL) was reached 2 h after administration. With transdermal application, maximal concentration was reached 48 h post-application; t1/2 was 36 h. With oral dosing, overall exposure after 5 days was 306 ng/mL·h, and Cavg 2.6 ng/mL. This corresponded to an AUC0—∞ for the 52 cm2 patch of 420 ng/mL·h and Cavg 2.2 ng/mL over 6 days. Clearance was not affected by age, gender, weight, or renal function.

Conclusion. The 52 cm 2 granisetron patch achieves a similar exposure to that of a 2 mg oral dose and provides continuous delivery of granisetron over 6 days. The patch may have utility in treating chemotherapy-induced nausea and vomiting where prolonged drug delivery is advantageous. No dose adjustments would be needed based on age or renal function.