Development of intranasal implantable devices for schizophrenia treatment

Preparation, characterisation, and testing of reservoir-based implantable devices loaded with tizanidine and lidocaine

Multiple sclerosis is a chronic neuroimmunological disorder that causes progressive disability, primarily in young adults. It places a significant burden on healthcare systems due to high medication costs and long-term care needs. Implantable devices offer a promising alternative for delivering sustained drug doses in the treatment of chronic conditions. This study introduces a novel long-acting subcutaneous implant for dual-drug delivery: tizanidine (TZ) for spasticity management and lidocaine (LD) for post-insertion pain relief. Reservoir-type implants were developed with TZ in the core and LD in the shell. Two fabrication methods-direct compression and vacuum compression moulding (VCM)-were evaluated for TZ-loaded pellets (3 mm diameter, ~ 10 mm length) using TZ base and TZ hydrochloride. Pellets were encapsulated inside a biodegradable polycaprolactone (PCL) tubular membrane to control drug release. Direct compression pellets, made with poly(vinyl pyrrolidone) and hydroxypropyl-β-cyclodextrin, disintegrated quickly, releasing TZ over 20 days. VCM pellets, formulated with PCL or PCL/poly(ethylene glycol) (PEG), offered prolonged release: up to 200 days for TZ base and 80 days for TZ hydrochloride. Adding PEG accelerated TZ release, reducing duration to 20 days (TZ base) and 125 days (TZ hydrochloride). LD was incorporated into the PCL membrane, providing up to three days of sustained release. Physicochemical analysis confirmed formulation homogeneity and no covalent interactions. These findings highlight the potential of this implant system for MS-related spasticity management, supporting further research into long-acting implants to improve treatment adherence and patient outcomes.

Schizophrenia Treatment Based on Sustained Release of Risperidone from Poly(lactic-co-glycolic) Acid Implantable Microarray Patch

Schizophrenia is one of the most severe mental disorders, affecting approximately 24 million people worldwide. Conventional treatments, such as drug-loaded implants and intramuscular injections, have several limitations, including pain during administration and the need for medical professionals to perform the procedure. In this study, a poly(lactic-co-glycolic) acid (PLGA)-based implantable microneedle patch (IMN) was developed for the transdermal delivery of risperidone (RIS) as a treatment for schizophrenia. RIS IMNs were prepared by sequentially casting gel-based formulations into microneedle (MN) molds. The patches were then characterized using microscopy, differential scanning calorimetry, and infrared spectroscopy, as well as through evaluations of MN insertion and RIS release. A selected formulation was further tested by evaluating its cytocompatibility and its ability to deliver RIS in a rat animal model. The RIS IMN demonstrated excellent mechanical properties, successfully inserting up to 378 nm into model skin, which is crucial for effective transdermal drug delivery. A biocompatibility study using human dermal fibroblasts showed no cytotoxicity, with cell viability and proliferation being close to 100%. The optimized formulation achieved a sustained in vitro release over 7 days, while ex vivo skin deposition and permeation studies showed over 65% RIS delivery efficiency. In vivo animal studies confirmed that RIS IMNs maintained therapeutic plasma concentrations throughout the nine-day experiment, with Cmax values of RIS and 9-OH RIS reaching 387.96 ± 194.02 and 139.89 ± 47.68 ng/mL at 6 and 96 h, respectively. In contrast, intramuscular injection showed a Cmax of 1756.70 ± 246.06 and 1377.38 ± 160.78 ng/mL at 2 and 6 h but lost therapeutic effect after just 24 h. These findings suggest that RIS IMNs offer significant clinical benefits for patients with schizophrenia, providing prolonged therapeutic effects with a simple, self-administering drug delivery system, reducing the need for frequent medical interventions.

Development of axitinib-loaded polymeric ocular implants for the treatment of posterior ocular diseases

Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are the primary causes of vision impairment and blindness worldwide. The current treatment for these diseases is an intravitreal injection of anti-VEGF agents, which are costly and require frequent injections. Implants can be used to sustain the release of drugs and minimize side effects. Axitinib (AX) is a potent VEGF receptor inhibitor and a promising candidate for treating posterior ocular diseases, such as diabetic retinopathy (DR) and age-related macular degeneration (AMD). A sustained release of AX was successfully achieved from 3D-printed AX-loaded implants fabricated using the well-known 3D printing technique, semi-solid extrusion (SSE). AX at concentrations of 10% w/w and 20% w/w was incorporated within the polycaprolactone (PCL) and Precirol®-based matrix. The fabricated implants were characterized via FTIR spectroscopy, SEM imaging, and thermal analysis. The implants were also evaluated for their drug release and biocompatibility. The AX-loaded implants exhibited thermal stability, and no chemical interactions were found between AX and the matrix components. The release mechanism study of AX revealed that the concentration of drug loading influenced AX release from the implant, with a 10% w/w and 20 %w/w of AX showing first-order and Korsmeyer-Peppas mechanism, respectively. A biocompatibility study using ARPE-19 cells confirmed that AX-loaded implants are nontoxic and safe for ocular use.

Reservoir-Type Subcutaneous Implantable Devices Containing Porous Rate Controlling Membranes for Sustained Delivery of Risperidone

Implantable drug delivery systems are crucial for achieving sustained delivery of active compounds to specific sites or systemic circulation. In this study, a novel reservoir-type implant combining a biodegradable rate-controlling membrane with a drug-containing core prepared using direct compression techniques is developed. The membrane is composed of poly(caprolactone) (PCL), and risperidone (RIS) served as the model drug. Characterization of both membranes and direct compressed pellets includes hardness testing, optical coherence tomography, mercury intrusion porosimetry, and surface morphology observation. In vitro release studies of RIS reveal that higher drug loading in the pellets extended-release duration up to 70 days when incorporated into membranes with four layers. Increasing the number of membrane layers slows the release rate further, ranging from 70 to 170 days depending on membrane thickness. Biocompatibility studies demonstrate that these implantable devices are non-toxic and biocompatible with cells in vitro. In vivo studies conduct in male Wistar rats demonstrate sustained release of RIS, with plasma levels showing a significant increase post-implantation at a relatively constant rate for up to 49 days. These results indicate that the developed implants have the potential to provide long-acting drug delivery to the systemic circulation.

Advancement in the Nose-to-Brain Drug delivery of FDA-approved drugs for the better management of Depression and Psychiatric disorders

The Prevalence of Depressive and Psychiatric disorders is increasing globally, and despite the availability of numerous FDA-approved drugs, treatment remains challenging. Many conventional antidepressants and antipsychotic formulations face issues such as low solubility, high first-pass metabolism, poor bioavailability, inadequate blood-brain barrier penetration, and systemic side effects. These challenges lead to reduced efficacy, slower onset of action, and decreased patient adherence to treatment. To address these problems, recent studies have explored the nose-to-brain route for drug delivery. This method offers several advantages, including non-invasive drug administration, direct access to the brain, rapid onset of action, reduced systemic exposure and side effects, avoidance of first-pass metabolism, enhanced bioavailability, precision dosing, and improved patient compliance. The formulations used for this approach include lipidic nanoparticles, polymeric nanoparticles, nasal gels, cubosomes, niosomes, polymeric micelles, nanosuspensions, nanoemulsions, nanocapsules, and elastosomes. This review analyzes and summarizes the published work on the nose-to-brain delivery of FDA-approved antidepressants and antipsychotic drugs, with a focus on the preparation, characterization, pharmacokinetics, pharmacodynamics, and toxicity profiling of these nanoformulations.

Systematic Approach in the Development of Chitosan Functionalized Iloperidone Nanoemulsions for Transnasal Delivery, In Vitro and In Vivo Studies

Iloperidone, a second-generation USFDA approved antipsychotic and BCS class II drug shows poor oral bioavailability of 28%. The present research deals with optimization of transnasal nanoemulsions of Iloperidone using Design Expert (Version 11) and further surface functionalization with chitosan for potentiating nose to brain delivery. Chitosan functionalized transnasal Iloperidone nanoemulsions were developed using oleic acid, charge inducer, Tween 80, Transcutol HP and chitosan using ultrasonication technique and evaluated. Droplet size, polydispersity index and zeta potential of Iloperidone nanoemulsions was found to be 173 ± 0.5 nm, 0.413 ± 0.2 and - 22.5 ± 0.1 mV while that of chitosan functionalized Iloperidone nanoemulsions was 146.4 ± 0.5 nm, 0.291 ± 0.02 and + 23.6 ± 0.3 mV respectively. Ninhydrin assay, TEM and FTIR studies confirmed surface functionalization of Iloperidone nanoemulsion droplets with chitosan. In vitro release of Iloperidone from nanoemulsions and chitosan functionalized nanoemulsions was 90.41 ± 2.1% and 72.02 ± 0.21% while ex vivo permeation of Iloperidone across goat nasal mucosa was 1270.58 ± 0.023 μg/cm2 and 1096.13 ± 0.043 μg/cm2 respectively at the end of 8 h. Studies in RPMI 2650 nasal and Neuro2A brain cell line lines indicated safety of chitosan functionalized transnasal Iloperidone nanoemulsions. Studies in Wistar rats showed increased cataleptic effects, reduced cognitive impairment and anxiety-related behaviour with greater brain accumulation indicating promising potential of this approach in nose to brain drug delivery.

Effect of the Addition of Inorganic Fillers on the Properties of Degradable Polymeric Blends for Bone Tissue Engineering

Bone tissue exhibits self-healing properties; however, not all defects can be repaired without surgical intervention. Bone tissue engineering offers artificial scaffolds, which can act as a temporary matrix for bone regeneration. The aim of this study was to manufacture scaffolds made of poly(lactic acid), poly(ε-caprolactone), poly(propylene fumarate), and poly(ethylene glycol) modified with bioglass, beta tricalcium phosphate (TCP), and/or wollastonite (W) particles. The scaffolds were fabricated using a gel-casting method and observed with optical and scanning electron microscopes. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG), wettability, and degradation tests were conducted. The highest content of TCP without W in the composition caused the highest hydrophilicity (water contact angle of 61.9 ± 6.3°), the fastest degradation rate (7% mass loss within 28 days), moderate ability to precipitate CaP after incubation in PBS, and no cytotoxicity for L929 cells. The highest content of W without TCP caused the highest hydrophobicity (water contact angle of 83.4 ± 1.7°), the lowest thermal stability, slower degradation (3% mass loss within 28 days), and did not evoke CaP precipitation. Moreover, some signs of cytotoxicity on day 1 were observed. The samples with both TCP and W showed moderate properties and the best cytocompatibility on day 4. Interestingly, they were covered with typical cauliflower-like hydroxyapatite deposits after incubation in phosphate-buffered saline (PBS), which might be a sign of their excellent bioactivity.

Dissolving microarray patches for transdermal delivery of risperidone for schizophrenia management

Schizophrenia is a psychiatric disorder that results from abnormal levels of neurotransmitters in the brain. Risperidone (RIS) is a common drug prescribed for the treatment of schizophrenia. RIS is a hydrophobic drug that is typically administered orally or intramuscularly. Transdermal drug delivery (TDD) could potentially improve the delivery of RIS. This study focused on the development of RIS nanocrystals (NCs), for the first time, which were incorporated into dissolving microneedle array patches (DMAPs) to facilitate the drug delivery of RIS. RIS NCs were formulated via wet-media milling technique using poly(vinylalcohol) (PVA) as a stabiliser. NCs with particle size of 300 nm were produced and showed an enhanced release profile up to 80 % over 28 days. Ex vivo results showed that 1.16 ± 0.04 mg of RIS was delivered to both the receiver compartment and full-thickness skin from NCs loaded DMAPs compared to 0.75 ± 0.07 mg from bulk RIS DMAPs. In an in vivo study conducted using female Sprague Dawley rats, both RIS and its active metabolite 9-hydroxyrisperidone (9-OH-RIS) were detected in plasma samples for 5 days. In comparison with the oral group, DMAPs improved the overall pharmacokinetic profile in plasma with a ∼ 15 folds higher area under the curve (AUC) value. This work has represented the novel delivery of the antipsychotic drug, RIS, through microneedles. It also offers substantial evidence to support the broader application of MAPs for the transdermal delivery of poorly water-soluble drugs.

Design of a Novel Delivery Efficiency Feedback System for Biphasic Dissolving Microarray Patches Based on Poly(Lactic Acid) and Moisture-Indicating Silica

Dissolving microarray patches (DMAPs) represent an innovative approach to minimally invasive transdermal drug delivery, demonstrating efficacy in delivering both small and large therapeutic molecules. However, concerns raised in end-user surveys have hindered their commercialization efforts. One prevalent issue highlighted in these surveys is the lack of clear indicators for successful patch insertion and removal time. To address this challenge, a color-change-based feedback system is devised, which confirms the insertion and dissolution of DMAPs, aiming to mitigate the aforementioned problems. The approach combines hydrophilic needles containing model drugs (fluorescein sodium and fluorescein isothiocyanate (FITC)-dextran) with a hydrophobic poly(lactic acid) baseplate infused with moisture-sensitive silica gel particles. The successful insertion and subsequent complete dissolution of the needle shaft are indicated by the progressive color change of crystal violet encapsulated in the silica. Notably, distinct color alterations on the baseplate, observed 30 min and 1 h after insertion for FITC-dextran and fluorescein sodium DMAPs respectively, signal the full dissolution of the needles, confirming the complete cargo delivery and enabling timely patch removal. This innovative feedback system offers a practical solution for addressing end-user concerns and may significantly contribute to the successful commercialization of DMAPs by providing a visualized drug delivery method.

Clopidogrel-loaded vascular grafts prepared using digital light processing 3D printing

The leading cause of death worldwide and a significant factor in decreased quality of life are the cardiovascular diseases. Endovascular operations like angioplasty, stent placement, or atherectomy are often used in vascular surgery to either dilate a narrowed blood artery or remove a blockage. As an alternative, a vascular transplant may be utilised to replace or bypass a dysfunctional or blocked blood vessel. Despite the advancements in endovascular surgery and its popularisation over the past few decades, vascular bypass grafting remains prevalent and is considered the best option for patients in need of long-term revascularisation treatments. Consequently, the demand for synthetic vascular grafts composed of biocompatible materials persists. To address this need, biodegradable clopidogrel (CLOP)-loaded vascular grafts have been fabricated using the digital light processing (DLP) 3D printing technique. A mixture of polylactic acid-polyurethane acrylate (PLA-PUA), low molecular weight polycaprolactone (L-PCL), and CLOP was used to achieve the required mechanical and biological properties for vascular grafts. The 3D printing technology provides precise detail in terms of shape and size, which lead to the fabrication of customised vascular grafts. The fabricated vascular grafts were fully characterised using different techniques, and finally, the drug release was evaluated. Results suggested that the performed 3D-printed small-diameter vascular grafts containing the highest CLOP cargo (20% w/w) were able to provide a sustained drug release for up to 27 days. Furthermore, all the CLOP-loaded 3D-printed materials resulted in a substantial reduction of the platelet deposition across their surface compared to the blank materials containing no drug. Haemolysis percentage for all the 3D-printed samples was lower than 5%. Moreover, 3D-printed materials were able to provide a supportive environment for cellular attachment, viability, and growth. A substantial increase in cell growth was detected between the blank and drug-loaded grafts.

Differences between criminal offender versus non-offender female patients with schizophrenia spectrum disorder: a retrospective cohort study

The purpose of this study was to investigate the difference between offender female patients (OFS) and non-offender female patients (NOFS) with schizophrenia spectrum disorder (SSD).The patients in this study were admitted to the university psychiatry in Zurich Switzerland between 1982 and 2016. Demography, psychopathology, comorbidity, and treatment differences were analyzed using binary statistics to compare 31 OFS and 29 matching NOFS with SSD. The Fisher's exact test was used for categorical data variables in small size samples and the Mann-Whitney-U-Test for nonparametric test variables, adjusted with the Benjamini and Hochberg method.The results indicate that the NOFS were cognitively more impaired, they were more likely to have had antipsychotic drugs prescribed (NOFS; 100%, OFS: 71%, OR 1.41, 95% CI 1.13-1.77, p=0.022) and their medication compliance was higher (NOFS: 84.6%, OFS: 4.5%, OR 0.09, 95% CI 0.00-0.08, p=0.000). In contrast, the OFS had completed compulsory school less often and the were observed to be more often homeless and socially isolated (OFS: 72.4%, NOFS: 34.6%, OR 4.96, 95% CI 1.58-15.6, p=0.026), self-disorders (OFS: 51.6%, NOFS: 11.1%, OR 8.53, 95% CI 2.12-34.32, p=0.011), delusions (OFS: 96.8%, NOFS: 63%, OR 17.65, 95% CI 2.08-149.99, p=0.014) and substance use disorder (51.6%, OR 0.27, 95% CI 0.09-0.85, p=0.039). Clinicians treating female offender patients with SSD should focus more on the treatment for substance use disorder, medication and early recognition of the illness for preventative purposes.

Nanomedicines for intranasal delivery: understanding the nano-bio interactions at the nasal mucus-mucosal barrier

INTRODUCTION

Intranasal administration is an effective drug delivery routes in modern pharmaceutics. However, unlike other in vivo biological barriers, the nasal mucosal barrier is characterized by high turnover and selective permeability, hindering the diffusion of both particulate drug delivery systems and drug molecules. The in vivo fate of administrated nanomedicines is often significantly affected by nano-biointeractions.

AREAS COVERED

The biological barriers that nanomedicines encounter when administered intranasally are introduced, with a discussion on the factors influencing the interaction between nanomedicines and the mucus layer/mucosal barriers. General design strategies for nanomedicines administered via the nasal route are further proposed. Furthermore, the most common methods to investigate the characteristics and the interactions of nanomedicines when in presence of the mucus layer/mucosal barrier are briefly summarized.

EXPERT OPINION

Detailed investigation of nanomedicine-mucus/mucosal interactions and exploration of their mechanisms provide solutions for designing better intranasal nanomedicines. Designing and applying nanomedicines with mucus interaction properties or non-mucosal interactions should be customized according to the therapeutic need, considering the target of the drug, i.e. brain, lung or nose. Then how to improve the precise targeting efficiency of nanomedicines becomes a difficult task for further research.

Incorporating surfactants into PCL microneedles for sustained release of a hydrophilic model drug

Polymeric microneedles (MNs) are widely used for sustained drug release due to their distinct advantages over other types of MNs. Poly-ε-caprolactone (PCL) stands out as a biodegradable and biocompatible hydrophobic polymer commonly employed in drug delivery applications. This study explores the impact of surfactants on the encapsulation and release rate of a model hydrophilic drug, minoxidil (MXD), from PCL MNs. Three nonionic surfactants, Tween 80, Span 60, and polyethylene glycol (PEG), were integrated into PCL MNs at varying concentrations. Compared to the other types of surfactants, PEG-containing PCL MNs exhibit enhanced insertion capabilities into a skin-simulant parafilm model and increased mechanical strength, suggesting facile penetration into the stratum corneum. Furthermore, MXD-PEG MNs show the highest encapsulation efficiency and are further characterized using FTIR, DSC and XRD. Their mechanical strength against different static forces was measured. The MNs exhibit a sustained release pattern over 20 days. Eventually, MXD-PEG MNs were subjected to penetration testing using chicken skin and required minimal insertion forces with no observed MN failure during experimentation even after compression with the maximum force applied (32 N per patch). Taken together, the present work demonstrates the feasibility of incorporating nonionic surfactants like PEG into the tips of hydrophobic PCL MNs for sustained delivery of a model hydrophilic drug. This formulation strategy can be used to improve patient compliance by allowing self-administration and achieving prolonged drug release.

An isocratic RP-HPLC-UV method for simultaneous quantification of tizanidine and lidocaine: application to in vitro release studies of a subcutaneous implant

Implantable devices have been widely investigated to improve the treatment of multiple diseases. Even with low drug loadings, these devices can achieve effective delivery and increase patient compliance by minimizing potential side effects, consequently enhancing the quality of life of the patients. Moreover, multi-drug products are emerging in the pharmaceutical field, capable of treating more than one ailment concurrently. Therefore, a simple analytical method is essential for detecting and quantifying different analytes used in formulation development and evaluation. Here, we present, for the first time, an isocratic method for tizanidine hydrochloride (TZ) and lidocaine (LD) loaded into a subcutaneous implant, utilizing reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with a UV detector. These implants have the potential to treat muscular spasticity while providing pain relief for several days after implantation. Chromatographic separation of the two drugs was accomplished using a C18 column, with a mobile phase consisting of 0.1% TFA in water and MeOH in a 58 : 42 ratio, flowing at 0.7 ml min-1. The method exhibited specificity and robustness, providing accurate and precise results. It displayed linearity within the range of 0.79 to 100 μg ml-1, with an R2 value of 1 for the simultaneous analysis of TZ and LD. The developed method demonstrated selectivity, offering limits of detection and quantification of 0.16 and 0.49 μg ml-1 for TZ, and 0.30 and 0.93 μg ml-1 for LD, respectively. Furthermore, the solution containing both TZ and LD proved stable under various storage conditions. While this study applied the method to assess an implant device, it has broader applicability for analysing and quantifying the in vitro drug release of TZ and LD from diverse dosage forms in preclinical settings.

Development of 3D-printed vaginal devices containing metronidazole for alternative bacterial vaginosis treatment

Bacterial vaginosis (BV) is an abnormal condition caused by the change of microbiota in the vagina. One of the most common bacteria found in the case of BV is Gardnerella vaginalis, which is categorised as anaerobic facultative bacteria. Currently, the available treatment for BV is the use of antibiotics, such as metronidazole (MTZ), in topical and oral dosage forms. The limitation of the currently available treatment is that multiple administration is required and thus, the patient needs to apply the drug frequently to maintain the drug efficacy. To address these limitations, this research proposed prolonged delivery of MTZ in the form of intravaginal devices made from biodegradable and biocompatible polymers. Semi-solid extrusion (SSE) 3D printing was used to prepare the intravaginal devices. The ratio of high and low molecular weight poly(caprolactone) (PCL) was varied to evaluate the effect of polymer composition on the drug release. The versatility of SSE 3D printer was used to print the intravaginal devices into two different shapes (meshes and discs) and containing two different polymer layers made from PCL and a copolymer of methyl vinyl ether and maleic anhydride (Gantrez™-AN119), which provided mucoadhesive properties. Indeed, this layer made from Gantrez™-AN119 increased ca. 5 times the mucoadhesive properties of the final 3D-printed devices (from 0.52 to 2.57 N). Furthermore, MTZ was homogenously dispersed within the polymer matrix as evidenced by scanning electron microscopy analysis. Additionally, in vitro drug release, and antibacterial activity of the MTZ-loaded intravaginal devices were evaluated. Disc formulations were able to sustain the release of MTZ for 72 h for formulations containing 70/30 and 60/40 ratio of high molecular weight/low molecular weight PCL. On the other hand, the discs containing a 50/50 ratio of high molecular weight/low molecular weight PCL showed up to 9 days of release. However, no significant differences in the MTZ release from the MTZ-loaded meshes (60/40 and 50/50 ratio of high molecular weight/low molecular weight PCL) were found after 24 h. The results showed that the different ratios of high and low molecular weight PCL did not significantly affect the MTZ release. However, the shape of the devices did influence the release of MTZ, showing that larger surface area of the meshes provided a faster MTZ release. Moreover, MTZ loaded 3D-printed discs (5% w/w) were capable of inhibiting the growth of Gardnerella vaginalis. These materials showed clear antimicrobial properties, exhibiting a zone of inhibition of 19.0 ± 1.3 mm. Based on these findings, the manufactured represent a valuable alternative approach to the current available treatment, as they were able to provide sustained release of MTZ, reducing the frequency of administration and thus improving patient compliance.

Tip loaded cyclodextrin-carvedilol complexes microarray patches

Carvedilol, a β-blocker prescribed for chronic heart failure, suffers from poor bioavailability and rapid first pass metabolism when administered orally. Herein, we present the development of tip microarray patches (MAPs) composed of ternary cyclodextrin (CD) complexes of carvedilol for transdermal delivery. The ternary complex with hydroxypropyl γ-cyclodextrin (HPγCD) and poly(vinyl pyrrolidone) (PVP) reduced the crystallinity of carvedilol, as evidenced by DSC, XRD, NMR, and SEM analysis. MAPs were fabricated using a two-step process with the ternary complex as the needle layer. The resulting MAPs were capable of breaching ex vivo neonatal porcine skin to a depth ≈600 μm with minimal impact to needle height. Upon insertion, the needle dissolved within 2 h, leading to the transdermal delivery of carvedilol. The MAPs displayed minimal toxicity and acceptable biocompatibility in cell assays. In rats, MAPs achieved significantly higher AUC levels of carvedilol than oral administration, with a delayed Tmax and sustained plasma levels over several days. These findings suggest that the carvedilol-loaded dissolving MAPs have the potential to revolutionise the treatment of chronic heart failure.

Liposome-loaded polymeric microneedles for enhanced skin deposition of rifampicin

Methicillin-resistant Staphylococcus aureus (MRSA) is a prevailing bacterial pathogen linked to superficial skin and soft tissue infections (SSTIs). Rifampicin (RIF), a potent antibiotic against systemic and localised staphylococcal infections, faces limitations due to its low solubility. This constraint hampers its therapeutic potential for MRSA-induced SSTIs. To address this, an advanced liposomal system was designed for efficient dermal RIF delivery. Rifampicin-loaded liposomes (LipoRIF) were embedded within polymeric dissolving microneedles (DMNs) to enable targeted intradermal drug delivery. A robust Design of Experiment (DoE) methodology guided the systematic preparation and optimisation of LipoRIF formulations. The optimal LipoRIF formulation integrated within polymeric DMNs. These LipoRIF-DMNs exhibited favourable mechanical properties and effective skin insertion characteristics. Notably, in vitro assays on skin deposition unveiled a transformative result - the DMN platform significantly enhanced LipoRIF deposition within the skin, surpassing LipoRIF dispersion alone. Moreover, LipoRIF-DMNs displayed minimal cytotoxicity toward cells. Encouragingly, rigorous in vitro antimicrobial evaluations demonstrated LipoRIF-DMNs' capacity to inhibit MRSA growth compared to the control group. LipoRIF-DMNs propose a potentially enhanced, minimally invasive approach to effectively manage SSTIs and superficial skin ailments stemming from MRSA infections.

3D-Printed Capsaicin-Loaded Injectable Implants for Targeted Delivery in Obese Patients

Diet-induced obesity and hyperlipidemia are a growing public health concern leading to various metabolic disorders. Capsaicin, a major bioactive compound obtained from natural chili peppers, has demonstrated its numerous beneficial roles in treating obesity and weight loss. Current treatment involves either administration of antiobesity drugs or surgical procedures such as Roux-en-Y-gastric bypass or sleeve gastrectomy, both of which are associated with serious side effects and poor patient acceptance. Capsaicin, a pungent molecule, has low oral bioavailability. Therefore, there is a need for the development of site-specific drug delivery system for capsaicin. The present study is aimed at preparing and characterizing 3D-printed capsaicin-loaded rod-shaped implants by thermoplastic extrusion-based 3D printing technology. The implants were printed with capsaicin-loaded into a biodegradable polymer, polycaprolactone, at different drug loadings and infill densities. The surface morphology revealed a smooth and uniform external surface without any capsaicin crystals. DSC thermograms showed no significant changes/exothermic events among the blends suggesting no drug polymer interactions. The in vitro release studies showed a biphasic release profile for capsaicin, and the release was sustained for more than three months (~ 85% released) irrespective of drug loading and infill densities. The HPLC method was stability-indicating and showed good resolution for its analogs, dihydrocapsaicin and nordihydrocapsaicin. The implants were stable for three months at accelerated conditions (40°C) without any significant decrease in the assay of capsaicin. Therefore, capsaicin-loaded implants can serve as a long-acting injectable formulation for targeting the adipose tissue region in obese patients.

Long-acting microneedle formulations

The minimally-invasive and painless nature of microneedle (MN) application has enabled the technology to obviate many issues with injectable drug delivery. MNs not only administer therapeutics directly into the dermal and ocular space, but they can also control the release profile of the active compound over a desired period. To enable prolonged delivery of payloads, various MN types have been proposed and evaluated, including dissolving MNs, polymeric MNs loaded or coated with nanoparticles, fast-separable MNs hollow MNs, and hydrogel MNs. These intricate yet intelligent delivery platforms provide an attractive approach to decrease side effects and administration frequency, thus offer the potential to increase patient compliance. In this review, MN formulations that are loaded with various therapeutics for long-acting delivery to address the clinical needs of a myriad of diseases are discussed. We also highlight the design aspects, such as polymer selection and MN geometry, in addition to computational and mathematical modeling of MNs that are necessary to help streamline and develop MNs with high translational value and clinical impact. Finally, up-scale manufacturing and regulatory hurdles along with potential avenues that require further research to bring MN technology to the market are carefully considered. It is hoped that this review will provide insight to formulators and clinicians that the judicious selection of materials in tandem with refined design may offer an elegant approach to achieve sustained delivery of payloads through the simple and painless application of a MN patch.

Solid implantable devices for sustained drug delivery

Implantable drug delivery systems (IDDS) are an attractive alternative to conventional drug administration routes. Oral and injectable drug administration are the most common routes for drug delivery providing peaks of drug concentrations in blood after administration followed by concentration decay after a few hours. Therefore, constant drug administration is required to keep drug levels within the therapeutic window of the drug. Moreover, oral drug delivery presents alternative challenges due to drug degradation within the gastrointestinal tract or first pass metabolism. IDDS can be used to provide sustained drug delivery for prolonged periods of time. The use of this type of systems is especially interesting for the treatment of chronic conditions where patient adherence to conventional treatments can be challenging. These systems are normally used for systemic drug delivery. However, IDDS can be used for localised administration to maximise the amount of drug delivered within the active site while reducing systemic exposure. This review will cover current applications of IDDS focusing on the materials used to prepare this type of systems and the main therapeutic areas of application.

L-Cysteine-Modified Transfersomes for Enhanced Epidermal Delivery of Podophyllotoxin

The purpose of this study was to evaluate L-cysteine-modified transfersomes as the topical carrier for enhanced epidermal delivery of podophyllotoxin (POD). L-cysteine-deoxycholic acid (LC-DCA) conjugate was synthesized via an amidation reaction. POD-loaded L-cysteine-modified transfersomes (POD-LCTs) were prepared via a thin membrane dispersion method and characterized for their particle size, zeta potential, morphology, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and in vitro release. Subsequently, in vitro skin permeation and retention, fluorescence distribution in the skin, hematoxylin-eosin staining and in vivo skin irritation were studied. The POD-LCTs formed spherical shapes with a particle size of 172.5 ± 67.2 nm and a zeta potential of -31.3 ± 6.7 mV. Compared with the POD-Ts, the POD-LCTs provided significantly lower drug penetration through the porcine ear skin and significantly increased the skin retention (p < 0.05). Meaningfully, unlike the extensive distribution of the POD-loaded transfersomes (POD-Ts) throughout the skin tissue, the POD-LCTs were mainly located in the epidermis. Moreover, the POD-LCTs did not induce skin irritation. Therefore, the POD-LCTs provided an enhanced epidermal delivery and might be a promising carrier for the topical delivery of POD.

Evaluation of Brain Targeting and Antipsychotic Activity of Nasally Administrated Ziprasidone Lipid-Polymer Hybrid Nanocarriers

The feasibility of using lipid-polymer hybrid (LPH) nanocarriers as a potential platform for the intranasal delivery of ziprasidone (ZP), a second-generation antipsychotic, was explored. Different ZP-loaded LPH composed of a PLGA core and cholesterol-lecithin lipid coat were prepared using a single step nano-precipitation self-assembly technique. Modulation of polymer, lipid and drug amounts, as well as stirring-speed-optimized LPH with a particle size of 97.56 ± 4.55 nm and a ZP entrapment efficiency (EE%) of 97.98 ± 1.22%. The brain deposition and pharmacokinetics studies proved the efficiency of LPH to traverse the blood-brain barrier (BBB) following intranasal delivery with a 3.9-fold increase in targeting efficiency compared to the intravenous (IV) ZP solution with a direct nose-to-brain transport percentage (DTP) of 74.68%. The ZP-LPH showed enhanced antipsychotic activity in terms of animals' hypermobility over an IV drug solution in schizophrenic rats. The obtained results showed that the fabricated LPH was able to improve ZP brain uptake and proved its antipsychotic efficiency.

Radiolabeled Risperidone microSPECT/CT Imaging for Intranasal Implant Studies Development

The use of intranasal implantable drug delivery systems has many potential advantages for the treatment of different diseases, as they can provide sustained drug delivery, improving patient compliance. We describe a novel proof-of-concept methodological study using intranasal implants with radiolabeled risperidone (RISP) as a model molecule. This novel approach could provide very valuable data for the design and optimization of intranasal implants for sustained drug delivery. RISP was radiolabeled with 125I by solid supported direct halogen electrophilic substitution and added to a poly(lactide-co-glycolide) (PLGA; 75/25 D,L-Lactide/glycolide ratio) solution that was casted on top of 3D-printed silicone molds adapted for intranasal administration to laboratory animals. Implants were intranasally administered to rats, and radiolabeled RISP release followed for 4 weeks by in vivo non-invasive quantitative microSPECT/CT imaging. Percentage release data were compared with in vitro ones using radiolabeled implants containing either 125I-RISP or [125I]INa and also by HPLC measurement of drug release. Implants remained in the nasal cavity for up to a month and were slowly and steadily dissolved. All methods showed a fast release of the lipophilic drug in the first days with a steadier increase to reach a plateau after approximately 5 days. The release of [125I]I− took place at a much slower rate. We herein demonstrate the feasibility of this experimental approach to obtain high-resolution, non-invasive quantitative images of the release of the radiolabeled drug, providing valuable information for improved pharmaceutical development of intranasal implants.

Development of 3D-printed subcutaneous implants using concentrated polymer/drug solutions

Implantable drug-eluting devices that provide therapeutic cover over an extended period of time following a single administration have potential to improve the treatment of chronic conditions. These devices eliminate the requirement for regular and frequent drug administration, thus reducing the pill burden experienced by patients. Furthermore, the use of modern technologies, such as 3D printing, during implant development and manufacture renders this approach well-suited for the production of highly tuneable devices that can deliver treatment regimens which are personalised for the individual. The objective of this work was to formulate subcutaneous implants loaded with a model hydrophobic compound, olanzapine (OLZ) using robocasting - a 3D-printing technique. The formulated cylindrical implants were prepared from blends composed of OLZ mixed with either poly(caprolactone) (PCL) or a combination of PCL and poly(ethylene)glycol (PEG). Implants were characterised using scanning electron microscopy (SEM), thermal analysis, infrared spectroscopy, and X-ray diffraction and the crystallinity of OLZ in the formulated devices was confirmed. In vitro release studies demonstrated that all the formulations were capable of maintaining sustained drug release over a period of 200 days, with the maximum percentage drug release observed to be c.a. 60 % in the same period.

Fabrication and Characterisation of 3D-Printed Triamcinolone Acetonide-Loaded Polycaprolactone-Based Ocular Implants

Triamcinolone acetonide (TA) is a corticosteroid that has been used to treat posterior segment eye diseases. TA is injected intravitreally in the management of neovascular disorders; however, frequent intravitreal injections result in many potential side effects and poor patient compliance. In this work, a 3D bioprinter was used to prepare polycaprolactone (PCL) implants loaded with TA. Implants were manufactured with different shapes (filament-, rectangular-, and circle-shaped) and drug loadings (5, 10, and 20%). The characterisation results showed that TA was successfully mixed and incorporated within the PCL matrix without using solvents, and drug content reached almost 100% for all formulations. The drug release data demonstrate that the filament-shaped implants (SA/V ratio~7.3) showed the highest cumulative drug release amongst all implant shapes over 180 days, followed by rectangular- (SA/V ratio~3.7) and circle-shaped implants (SA/V ratio~2.80). Most implant drug release data best fit the Korsmeyer−Peppas model, indicating that diffusion was the prominent release mechanism. Additionally, a biocompatibility study was performed; the results showed >90% cell viability, thus proving that the TA-loaded PCL implants were safe for ocular application.

Valorization of Kraft Lignin from Black Liquor in the Production of Composite Materials with Poly(caprolactone) and Natural Stone Groundwood Fibers

The development of new materials is currently focused on replacing fossil-based plastics with sustainable materials. Obtaining new bioplastics that are biodegradable and of the greenest possible origin could be a great alternative for the future. However, there are some limitations-such as price, physical properties, and mechanical properties-of these bioplastics. In this sense, the present work aims to explore the potential of lignin present in black liquor from paper pulp production as the main component of a new plastic matrix. For this purpose, we have studied the simple recovery of this lignin using acid precipitation, its thermoplastification with glycerin as a plasticizing agent, the production of blends with poly(caprolactone) (PCL), and finally the development of biocomposite materials reinforcing the blend of thermoplastic lignin and PCL with stone groundwood fibers (SGW). The results obtained show that thermoplastic lignin alone cannot be used as a bioplastic. However, its combination with PCL provided a tensile strength of, e.g., 5.24 MPa in the case of a 50 wt.% blend. In addition, when studying the properties of the composite materials, it was found that the tensile strength of a blend with 20 wt.% PCL increased from 1.7 to 11.2 MPa with 40 wt.% SGW. Finally, it was proven that through these biocomposites it is possible to obtain a correct fiber-blend interface.

Preparation and characterization of flexible furosemide-loaded biodegradable microneedles for intradermal drug delivery

Transdermal drug delivery systems are a useful and minimally invasive alternative to other drug administration routes. Biodegradable polymeric microneedles (MNs) are widely used in controlled-release drug delivery due to their tunable properties and ease of patient self-administration. Polylactic-co-glycolic acid (PLGA) is often used for sustained drug release owing to special intrinsic properties including biocompatibility and biodegradability, which offer excellent applicability in preparing MNs. Congestive heart failure (CHF) is characterized by fluid overload during acute exacerbation, necessitating frequent patient hospitalization for continuous intravenous (i.v.) diuretic therapy. In the present study, we incorporated furosemide (FUR) as a model drug into flexible PLGA MN skin patches for potential intradermal delivery to overcome the limitations associated with i.v. diuresis. The MNs were fabricated by a casting-mold technique and consisted of two main parts, PLGA needle tips loaded with varying concentrations of FUR and a flexible backing layer comprising sodium alginate and glycerol. MN formulations were characterized by SEM and exhibited a uniform pyramidal shape. The measured surface pH of all samples suggested that no skin irritation is expected upon application. High encapsulation efficiency was obtained for FUR-MN formulations in which a decrease was noted as the FUR/PLGA ratio decreased. Drug loading content ranged from 19.1 ± 1% to 28.9 ± 1.4%. Successful insertion of MNs into a Parafilm® skin simulant model suggested that MNs will easily penetrate the skin's outermost layer, the stratum corneum, and will permit intradermal delivery of FUR. The MNs were further characterized by analytical methods. Finally, the MNs exhibited an initial burst release followed by a sustained release of FUR. Self-administered FUR-MNs can open new avenues to overcome i.v. drip limitations and increase patient compliance.