Recent advances in long-acting nanoformulations for delivery of antiretroviral drugs

Unveiling the Performance of Co-Assembled Hybrid Nanocarriers: Moving towards the Formation of a Multifunctional Lipid/Random Copolymer Nanoplatform

Despite the appealing properties of random copolymers, the use of these biomaterials in association with phospholipids is still limited, as several aspects of their performance have not been investigated. The aim of this work is the formulation of lipid/random copolymer platforms and the comprehensive study of their features by multiple advanced characterization techniques. Both biomaterials are amphiphilic, including two phospholipids (1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)) and a statistical copolymer of oligo (ethylene glycol) methyl ether methacrylate (OEGMA) and 2-(diisopropylamino) ethyl methacrylate (DIPAEMA). We examined the design parameters, including the lipid composition, the % comonomer ratio, and the lipid-to-polymer ratio that could be critical for their behavior. The structures were also probed in different conditions. To the best of the authors' knowledge, this is the first time that P(OEGMA-co-DIPAEMA)/lipid hybrid colloidal dispersions have been investigated from a membrane mechanics, biophysical, and morphological perspective. Among other parameters, the copolymer architecture and the hydrophilic to hydrophobic balance are deemed fundamental parameters for the biomaterial co-assembly, having an impact on the membrane's fluidity, morphology, and thermodynamics. Exploiting their unique characteristics, the most promising candidates were utilized for methotrexate (MTX) loading to explore their encapsulation capability and potential antitumor efficacy in vitro in various cell lines.

Accelerated and Biopredictive In Vitro Release Testing Strategy for Single Agent and Combination Long-Acting Injectables

The purpose of this study was to develop an in vitro release testing (IVRT) strategy to predict the pre-clinical performance of single agent and combination long acting injectable (LAI) suspension products. Two accelerated IVRT methods were developed using USP apparatus 2 to characterize initial, intermediate, and terminal phases of drug release. Initial and intermediate phases were captured using a suspension cup with moderate agitation to ensure a constant, low surface area exposure of the LAI suspension to the release media. The terminal phase was obtained by exposing the LAI suspension to a high initial paddle speed. This resulted in smaller suspension particulates with high cumulative surface area that were dispersed throughout the release media, enabling rapid drug release. The in vitro release profiles obtained with these two methods in 48 h or less were independently time scaled to reflect the in vivo time scale of approximately 1800 h. Level-A in vitro in vivo correlations (IVIVCs) were separately developed for each method and active pharmaceutical ingredient (API) using in vivo absorption profiles obtained by deconvolution of rat plasma concentration-time profiles. The IVIVCs were successfully validated for each API. This work provides a framework for evaluating individual phases of drug release of complex LAIs to ultimately predict their in vivo performance.

Injectable long-acting formulations (ILAFs) and manufacturing techniques

INTRODUCTION

Most therapeutics delivered using short-acting formulations need repeated administration, which can harm patient compliance and raise failure risks related to inconsistent treatment. Injectable long-acting formulations (ILAFs) are controlled/sustained-release formulations fabricated to deliver active pharmaceutical ingredients (APIs) and extend their half-life over days to months. Longer half-lives of ILAFs minimize the necessity for frequent doses, increase patient compliance, and reduce the risk of side effects from intravenous (IV) infusions. Using ILAF technologies, the immediate drug release can also be controlled, thereby minimizing potential adverse effects due to high initial drug blood concentrations.

AREA COVERED

In this review, we have discussed various ILAFs, their physiochemical properties, fabrication technologies, advantages, and practical issues, as well as address some major challenges in their application. Especially, the approved ILAFs are highlighted.

EXPERT OPINION

ILAFs are sustained-release formulations with extended activity, which can improve patient compliance. ILAFs are designed to deliver APIs like proteins and peptides and extend their half-life over days to months. The specific properties of each ILAF preparation, such as extended-release and improved drug targeting capabilities, make them an effective approach for precise and focused therapy. Furthermore, this is especially helpful for biopharmaceuticals with short biological half-lives and low stability since most environmental conditions can protect them from sustained-release delivery methods.

Interactions between nanoparticles and lymphatic systems: Mechanisms and applications in drug delivery

The lymphatic system has garnered significant attention in drug delivery research due to the advantages it offers, such as enhancing systemic exposure and enabling lymph node targeting for nanomedicines via the lymphatic delivery route. The journey of drug carriers involves transport from the administration site to the lymphatic vessels, traversing the lymph before entering the bloodstream or targeting specific lymph nodes. However, the anatomical and physiological barriers of the lymphatic system play a pivotal role in influencing the behavior and efficiency of carriers. To expedite research and subsequent clinical translation, this review begins by introducing the composition and classification of the lymphatic system. Subsequently, we explore the routes and mechanisms through which nanoparticles enter lymphatic vessels and lymph nodes. The review further delves into the interactions between nanomedicine and body fluids at the administration site or within lymphatic vessels. Finally, we provide a comprehensive overview of recent advancements in lymphatic delivery systems, addressing the challenges and opportunities inherent in current systems for delivering macromolecules and vaccines.

Recent Advances in Nanotechnology-Based Drug Delivery Systems for the Diagnosis and Treatment of Reproductive Disorders

Over the past decade, nanotechnology has seen extensive integration into biomedical applications, playing a crucial role in biodetection, drug delivery, and diagnostic imaging. This is especially important in reproductive health care, which has become an emerging and significant area of research. Global concerns have intensified around disorders such as infertility, endometriosis, ectopic pregnancy, erectile dysfunction, benign prostate hyperplasia, sexually transmitted infections, and reproductive cancers. Nanotechnology presents promising solutions to address these concerns by introducing innovative tools and techniques, facilitating early detection, targeted drug delivery, and improved imaging capabilities. Through the utilization of nanoscale materials and devices, researchers can craft treatments that are not only more precise but also more effective, significantly enhancing outcomes in reproductive healthcare. Looking forward, the future of nanotechnology in reproductive medicine holds immense potential for reshaping diagnostics, personalized therapies, and fertility preservation. The utilization of nanotechnology-driven drug delivery systems is anticipated to elevate treatment effectiveness, minimize side effects, and offer patients therapies that are not only more precise but also more efficient. This review aims to delve into the various types, properties, and preparation techniques of nanocarriers specifically designed for drug delivery in the context of reproductive disorders, shedding light on the current landscape and potential future directions in this dynamic field.

Recent developments in the use of nanocrystals to improve bioavailability of APIs

Nanocrystals refer to materials with at least one dimension smaller than 100 nm, composing of atoms arranged in single crystals or polycrystals. Nanocrystals have significant research value as they offer unique advantages over conventional pharmaceutical formulations, such as high bioavailability, enhanced targeting selectivity and controlled release ability and are therefore suitable for the delivery of a wide range of drugs such as insoluble drugs, antitumor drugs and genetic drugs with broad application prospects. In recent years, research on nanocrystals has been progressively refined and new products have been launched or entered the clinical phase of studies. However, issues such as safety and stability still stand that need to be addressed for further development of nanocrystal formulations, and significant gaps do exist in research in various fields in this pharmaceutical arena. This paper presents a systematic overview of the advanced development of nanocrystals, ranging from the preparation approaches of nanocrystals with which the bioavailability of poorly water-soluble drugs is improved, critical properties of nanocrystals and associated characterization techniques, the recent development of nanocrystals with different administration routes, the advantages and associated limitations of nanocrystal formulations, the mechanisms of physical instability, and the enhanced dissolution performance, to the future perspectives, with a final view to shed more light on the future development of nanocrystals as a means of optimizing the bioavailability of drug candidates. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Long-term antitrypanosomal effect of quinapyramine sulphate-loaded oil-based nanosuspension in T. evansi-infected mouse model

The goal of the present work consisted of the formulation development and evaluation of quinapyramine sulphate (QS)-loaded long-acting oil-based nanosuspension for improved antitrypanosomal effect. QS was transformed into a hydrophobic ionic complex using anionic sodium cholate (Na.C). The complex was characterized by FTIR, DSC, and XRD. Oil-based nanosuspension was prepared by dispersing the QS-Na.C complex in thixotropically thickened olive oil. The nanoformulation was found to be cytocompatible (82.5 ± 5.87% cell viability at the minimum effective concentration [MEC]) in THP-1 cell lines and selectively trypanotoxic (p < 0.0001). The pharmacokinetic studies of QS-Na.C complex-loaded oily nanosuspension showed 13.54-fold, 7.09-fold, 1.78-fold, and 17.35-fold increases in t1/2, AUC0-∞, Vz/F, and MRT0-ꝏ, respectively, as compared to free QS. Moreover, a 7.08-fold reduction in plasma clearance was observed after the treatment with the optimized formulation in Wistar rats. Furthermore, treatment with QS-Na.C complex-loaded oily nanosuspension (7.5 mg/kg) in T. evansi-infected mice model showed the absence of parasitaemia for more than 75 days after the treatment during in vivo efficacy studies. The efficacy of the treatment was assessed by observation of blood smear and PCR assay for DNA amplification. To conclude, our findings suggest that the efficient delivery of QS from the developed QS-Na.C complex-loaded oily nanosuspension could be a promising treatment option for veterinary infections against trypanosomiasis.

Development of long-acting injectable suspensions by continuous antisolvent crystallization: An integrated bottom-up process

Our present work elucidated the operational feasibility of direct generation and stabilization of long-acting injectable (LAI) suspensions of a practically insoluble drug, itraconazole (ITZ), by combining continuous liquid antisolvent crystallization with downstream processing (i.e., centrifugal filtration and reconstitution). A novel microchannel reactor-based bottom-up crystallization setup was assembled and optimized for the continuous production of micro-suspension. Based upon the solvent screening and solubility study, N-methyl pyrrolidone (NMP) was selected as the optimal solvent and an impinging jet Y-shaped microchannel reactor (MCR) was selected as the fluidic device to provide a reproducible homogenous mixing environment. Operating parameters such as solvent to antisolvent ratio (S/AS), total jet liquid flow rates (TFRs), ITZ feed solution concentration and the maturation time in spiral tubing were tailored to 1:9 v/v, 50 mL/min, 10 g/100 g solution, and 96 h, respectively. Vitamin E TPGS (0.5% w/w) was found to be the most suitable excipient to stabilize ITZ particles amongst 14 commonly used stabilizers screened. The effect of scaling up from 25 mL to 15 L was evaluated effectively with in situ monitoring of particle size distribution (PSD) and solid-state form. Thereafter, the suspension was subjected to centrifugal filtration to remove excess solvent and increase ITZ solid fraction. As an alternative, an even more concentrated wet pellet was reconstituted with an aqueous solution of 0.5% w/w Vitamin E TPGS as resuspending agent. The ITZ LAI suspension (of 300 mg/mL solid concentration) has the optimal PSD with a D10 of 1.1 ± 0.3 µm, a D50 of 3.53 ± 0.4 µm and a D90 of 6.5 ± 0.8 µm, corroborated by scanning electron microscopy (SEM), as remained stable after 548 days of storage at 25 °C. Finally, in vitro release methods using Dialyzer, dialysis membrane sac were investigated for evaluation of dissolution of ITZ LAI suspensions. The framework presented in this manuscript provides a useful guidance for development of LAI suspensions by an integrated bottom-up approach using ITZ as model API.

Advances in long-acting slow effective release antiretroviral therapies for treatment and prevention of HIV infection

Adherence to daily oral antiretroviral therapy (ART) is a barrier to both treatment and prevention of human immunodeficiency virus (HIV) infection. To overcome limitations of life-long daily regimen adherence, long-acting (LA) injectable antiretroviral (ARV) drugs, nanoformulations, implants, vaginal rings, microarray patches, and ultra-long-acting (ULA) prodrugs are now available or in development. These medicines enable persons who are or at risk for HIV infection to be treated with simplified ART regimens. First-generation LA cabotegravir, rilpivirine, and lenacapavir injectables and a dapivirine vaginal ring are now in use. However, each remains limited by existing dosing intervals, ease of administration, or difficulties in finding drug partners. ULA ART regimens provide an answer, but to date, such next-generation formulations remain in development. Establishing the niche will require affirmation of extended dosing, improved access, reduced injection volumes, improved pharmacokinetic profiles, selections of combination treatments, and synchronization of healthcare support. Based on such needs, this review highlights recent pharmacological advances and a future treatment perspective. While first-generation LA ARTs are available for HIV care, they remain far from ideal in meeting patient needs. ULA medicines, now in advanced preclinical development, may close gaps toward broader usage and treatment options.

Polymeric in situ forming depots for long-acting drug delivery systems

Polymeric in situ forming depots have emerged as highly promising drug delivery systems for long-acting applications. Their effectiveness is attributed to essential characteristics such as biocompatibility, biodegradability, and the ability to form a stable gel or solid upon injection. Moreover, they provide added versatility by complementing existing polymeric drug delivery systems like micro- and nanoparticles. The formulation's low viscosity facilitates manufacturing unit operations and enhances delivery efficiency, as it can be easily administered via hypodermic needles. The release mechanism of drugs from these systems can be predetermined using various functional polymers. To enable unique depot design, numerous strategies involving physiological and chemical stimuli have been explored. Important assessment criteria for in situ forming depots include biocompatibility, gel strength and syringeability, texture, biodegradation, release profile, and sterility. This review focuses on the fabrication approaches, key evaluation parameters, and pharmaceutical applications of in situ forming depots, considering perspectives from academia and industry. Additionally, insights about the future prospects of this technology are discussed.

Do Mixtures of Beads with Different Sizes Improve Wet Stirred Media Milling of Drug Suspensions?

The impacts of bead sizes and bead mixtures on breakage kinetics, the number of milling cycles applied to prevent overheating, and power consumption during the nanomilling of drug (griseofulvin) suspensions were investigated from both an experimental and theoretical perspective. Narrowly sized zirconia beads with nominal sizes of 100, 200, and 400 µm and their half-and-half binary mixtures were used at 3000 and 4000 rpm with two bead loadings of 0.35 and 0.50. Particle size evolution was measured during the 3 h milling experiments using laser diffraction. An nth-order breakage model was fitted to the experimental median particle size evolution, and various microhydrodynamic parameters were calculated. In general, the beads and their mixtures with smaller median sizes achieved faster breakage. While the microhydrodynamic model explained the impacts of process parameters, it was limited in describing bead mixtures. For additional test runs performed, the kinetics model augmented with a decision tree model using process parameters outperformed that augmented with an elastic-net regression model using the microhydrodynamic parameters. The evaluation of the process merit scores suggests that the use of bead mixtures did not lead to notable process improvement; 100 µm beads generally outperformed bead mixtures and coarser beads in terms of fast breakage, low power consumption and heat generation, and low intermittent milling cycles.

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.

Prodrug approaches for the development of a long-acting drug delivery systems

Long-acting formulations are designed to reduce dosing frequency and simplify dosing schedules by providing an extended duration of action. One approach to obtain long-acting formulations is to combine long-acting prodrugs (LA-prodrug) with existing or emerging drug delivery technologies (DDS). The design criteria for long-acting prodrugs are distinct from conventional prodrug strategies that alter absorption, distribution, metabolism, and excretion (ADME) parameters. Our review focuses on long-acting prodrug delivery systems (LA-prodrug DDS), which is a subcategory of long-acting formulations where prodrug design enables DDS formulation to achieve an extended duration of action that is greater than the parent drug. Here, we define LA-prodrugs as the conjugation of an active pharmaceutical ingredient (API) to a promoiety group via a cleavable covalent linker, where both the promoiety and linker are selected to enable formulation and administration from a drug delivery system (DDS) to achieve an extended duration of action. These LA-prodrug DDS results in an extended interval where the API is within a therapeutic range without necessarily altering ADME as is typical of conventional prodrugs. The conversion of the LA-prodrug to the API is dependent on linker cleavage, which can occur before or after release from the DDS. The requirement for linker cleavage provides an additional tool to prolong release from these LA-prodrug DDS. In addition, the physicochemical properties of drugs can be tuned by promoiety selection for a particular DDS. Conjugation with promoieties that are carriers or amenable to assembly into carriers can also provide access to formulations designed for extending duration of action. LA-prodrugs have been applied to a wide variety of drug delivery strategies and are categorized in this review by promoiety size and complexity. Small molecule promoieties (typically MW < 1000 Da) have been used to improve encapsulation or partitioning as well as broaden APIs for use with traditional long-acting formulations such as solid drug dispersions. Macromolecular promoieties (typically MW > 1000 Da) have been applied to hydrogels, nanoparticles, micelles, dendrimers, and polymerized prodrug monomers. The resulting LA-prodrug DDS enable extended duration of action for active pharmaceuticals across a wide range of applications, with target release timescales spanning days to years.

Creation of a ready-to-use brexpiprazole suspension and the inflammation-mediated pharmacokinetics by intramuscular administration

Brexpiprazole (BPZ), which is approved for the treatment of schizophrenia and major depressive disorder, has the potential to meet diverse clinical needs. This study aimed to develop a long-acting injectable (LAI) formulation of BPZ that could provide sustained therapeutic benefits. A library of BPZ prodrugs was screened through esterification, and BPZ laurate (BPZL) was identified as an optimal candidate. To achieve stable aqueous suspensions, a pressure- and nozzle size-controlled microfluidization homogenizer was utilized. The pharmacokinetics (PK) profiles, considering dose and particle size modulation, were investigated following a single intramuscular injection in beagles and rats. BPZL treatment resulted in sustained plasma concentrations above the median effective concentration (EC₅₀) for 2∼3 weeks, without exhibiting an initial burst release. Histological examination of foreign body reaction (FBR) in rats revealed the morphological evolution of an inflammation-mediated drug depot, confirming the sustained release mechanism of BPZL. These findings provide strong support for the further development of a ready-to-use LAI suspension of BPZL, which could potentially enhance treatment outcomes, improve patient adherence, and address the clinical challenges associated with long-term regimens of schizophrenia spectrum disorders (SSD).

Development of dissolving microneedles for intradermal delivery of the long-acting antiretroviral drug bictegravir

Oral administration and intramuscular (IM) injection are commonly recommended options for human immunodeficiency virus (HIV) treatment. However, poor patient compliance due to daily oral dosing, pain at injection sites and the demand for trained healthcare staff for injections limit the success of these administration routes, especially in low-resource settings. To overcome these limitations, for the first time, we propose novel bilayer dissolving microneedles (MNs) for the intradermal delivery of long-acting nanosuspensions of the antiretroviral (ARV) drug bictegravir (BIC) for potential HIV treatment and prevention. The BIC nanosuspensions were prepared using a wet media milling technique on a laboratory scale with a particle size of 358.99 ± 18.53 nm. The drug loading of nanosuspension-loaded MNs and BIC powder-loaded MNs were 1.87 mg/0.5 cm² and 2.16 mg/0.5 cm², respectively. Both dissolving MNs exhibited favorable mechanical and insertion ability in the human skin simulant Parafilm® M and excised neonatal porcine skin. Importantly, the pharmacokinetic profiles of Sprague Dawley rats demonstrated that dissolving MNs were able to intradermally deliver 31% of drug loading from nanosuspension-loaded MNs in the form of drug depots. After a single application, both coarse BIC and BIC nanosuspensions achieved sustained release, maintaining plasma concentrations above human therapeutic levels (162 ng/mL) in rats for 4 weeks. These minimally invasive and potentially self-administered MNs could improve patient compliance, providing a promising platform for the delivery of nanoformulated ARVs and resulting in prolonged drug release, particularly for patients in low-resource settings.

Long-acting Parenteral Drug Delivery Systems for the Treatment of Chronic Diseases

The management of chronic conditions often requires patients to take daily medication for an extended duration. However, the need for daily dosing can lead to nonadherence to the therapy, which can result in the recurrence of the disease. Long-acting parenteral drug delivery systems have the potential to improve the treatment of chronic conditions. These systems use various technologies, such as oil-based injectables, PLGA-based microspheres, and in situ forming gel-based depots, to deliver different types of drugs. The use of long-acting parenteral formulations for the treatment of chronic infections such as HIV/AIDS and tuberculosis is a recent development in the field. Researchers are also exploring the use of long-acting parenteral formulations for the treatment of malaria, with the aim of reducing dosing frequency and improving adherence to treatment. This review discusses various aspects of long-acting formulation development, including the impact of the physicochemical properties of the drug, the type of long-acting formulation, and the route of administration. The clinical significance of long-acting formulations and recent advances in the field, such as long-acting nanoformulations and long-acting products currently in clinical trials, have also been highlighted.

Development of Hybrid DSPC:DOPC:P(OEGMA950-DIPAEMA) Nanostructures: The Random Architecture of Polymeric Guest as a Key Design Parameter

Hybrid nanoparticles have gained a lot of attention due to their advantageous properties and versatility in pharmaceutical applications. In this perspective, the formation of novel systems and the exploration of their characteristics not only from a physicochemical but also from a biophysical perspective could promote the development of new nanoplatforms with well-defined features. In the current work, lipid/copolymer bilayers were formed in different lipid to copolymer ratios and examined via differential scanning calorimetry as a preformulation study to decipher the interactions between the biomaterials, followed by nanostructure preparation by the thin-film hydration method. Physicochemical and toxicological evaluations were conducted utilizing light scattering techniques, fluorescence spectroscopy, and MTS assay. 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) in different weight ratios were the chosen lipids, while a linear random copolymer with pH- and thermoresponsive properties comprised of oligo (ethylene glycol) methyl ether methacrylate (OEGMA) and 2-(diisopropylamino) ethyl methacrylate (DIPAEMA) in different ratios was used. According to our results, non-toxic hybrid nanosystems with stimuli-responsive properties were successfully formulated, and the main parameters influencing their overall performance were the hydrophilic/hydrophobic balance, lipid to polymer ratio, and more importantly the random copolymer topology. Hopefully, this investigation can promote a better understanding of the factors affecting the behavior of hybrid systems.

Design of Montelukast Nanocrystalline Suspension for Parenteral Prolonged Delivery

Background

Montelukast (MTK), a representative leukotriene receptor antagonist, is currently being investigated as a potential candidate for treating Alzheimer’s disease. For potent and effective dosing in elderly patients, a parenteral prolonged delivery system is favored, with improved medication adherence with reduced dosage frequency.

Purpose

This study aimed to design a nanocrystalline suspension (NS)-based MTK prolonged delivery system and evaluate its pharmacokinetics profile and local tolerability following subcutaneous administration.

Methods

To decelerate the dissolution rate, the amorphous MTK raw material was transformed into a crystalline state using a solvent-mediated transformation method and subsequently formulated into NS using a bead-milling technique. The MTK NSs were characterized by morphology, particle size, crystallinity, and in vitro dissolution profiles. The pharmacokinetic profile and local tolerability at the injection site following subcutaneous injection of MTK suspension were evaluated in rats.

Results

Microscopic and physical characterization revealed that the amorphous MTK powder was lucratively transformed into a crystalline form in acidic media (pH 4). MTK crystalline suspensions with different diameters (200 nm, 500 nm, and 3 μm) were uniformly prepared using bead-milling technology, employing polysorbate 80 as suspending agent. Prepared crystalline suspensions exhibited analogous crystallinity (melting point, 150°C) and size-dependent in vitro dissolution profiles. MTK NSs with particle sizes of 200 nm and 500 nm provided a protracted pharmacokinetic profile for up to 4 weeks in rats, with a higher maximum drug concentration in plasma than the 3 μm-sized injectable suspensions. Histopathological examination revealed that MTK NS caused chronic granulomatous inflammation at the injection site, which resolved after 4 weeks.

Conclusion

The MTK parenteral NS delivery system is expected to be a valuable tool for treating Alzheimer’s disease with extended dose intervals.

Microcrystals of Ketal-Linked Paliperidone Prodrugs for Long-Acting Antipsychotics

Intramuscularly injectable long-acting prodrug-based microcrystals (MCs) are of particular interest for chronic disease management. Nevertheless, current prevalently used linkers degraded by enzymes have the potential drawback of substantial differences in enzyme levels between individuals. Here, we reported the synthesis of a stearyl-modified paliperidone prodrug (SKP) with an acid-sensitive ketal linker for developing long-acting MC antipsychotics. SKP-MCs of three different sizes were prepared and systematically examined. We found that paliperidone exposure in SKP-MC-treated rats was prolonged compared with that in rats treated with the commercial antipsychotic Invega Sustenna and that the drug release rate decreased with increasing MC size. In inflammation-inhibition-model rats, paliperidone release from the SKP-MCs was considerably decreased, indicating that the immune-mediated foreign-body response after intramuscular administration boosted paliperidone release. Our findings will provide valuable insights into in vivo drug release from prodrug-based MC formulations. The ketal-linked prodrug strategy might be a new solution for developing long-acting prodrug formulations of hydroxyl-group-bearing drugs.

Real-Life Therapeutic Concentration Monitoring of Long-Acting Cabotegravir and Rilpivirine: Preliminary Results of an Ongoing Prospective Observational Study in Switzerland

SHCS#879 is an ongoing Switzerland-wide multicenter observational study conducted within the Swiss HIV Cohort Study (SHCS) for the prospective follow-up of people living with HIV (PLWH) receiving long-acting injectable cabotegravir-rilpivirine (LAI-CAB/RPV). All adults under LAI-CAB/RPV and part of SHCS are enrolled in the project. The study addresses an integrated strategy of treatment monitoring outside the stringent frame of controlled clinical trials, based on relevant patient characteristics, clinical factors, potential drug-drug interactions, and measurement of circulating blood concentrations. So far, 91 blood samples from 46 PLWH have been collected. Most individuals are less than 50 years old, with relatively few comorbidities and comedications. The observed concentrations are globally in accordance with the available values reported in the randomized clinical trials. Yet, low RPV concentrations not exceeding twice the reported protein-adjusted 90% inhibitory concentration have been observed. Data available at present confirm a considerable between-patient variability overall. Based on the growing amount of PK data accumulated during this ongoing study, population pharmacokinetic analysis will characterize individual concentration-time profiles of LAI-CAB/RPV along with their variability in a real-life setting and their association with treatment response and tolerability, thus bringing key data for therapeutic monitoring and precision dosage adjustment of this novel long-acting therapy.

Drug Nanocrystals for Active Tumor-Targeted Drug Delivery

Drug nanocrystals, which are comprised of active pharmaceutical ingredients and only a small amount of essential stabilizers, have the ability to improve the solubility, dissolution and bioavailability of poorly water-soluble drugs; in turn, drug nanocrystal technology can be utilized to develop novel formulations of chemotherapeutic drugs. Compared with passive targeting strategy, active tumor-targeted drug delivery, typically enabled by specific targeting ligands or molecules modified onto the surface of nanomedicines, circumvents the weak and heterogeneous enhanced permeability and retention (EPR) effect in human tumors and overcomes the disadvantages of nonspecific drug distribution, high administration dosage and undesired side effects, thereby contributing to improving the efficacy and safety of conventional nanomedicines for chemotherapy. Continuous efforts have been made in the development of active tumor-targeted drug nanocrystals delivery systems in recent years, most of which are encouraging and also enlightening for further investigation and clinical translation.

Development of cationic Isometamidium chloride loaded long-acting lipid nanoformulation: optimization, cellular uptake, pharmacokinetics, biodistribution, and immunohistochemical evaluation

The aim of the present work involved the development and evaluation of long-acting Isometamidium chloride (ISMM)-Docusate sodium (DS) complex loaded lipid nanoparticles (LA ISMM-DS LNP). The development involved screening various anionic complexing agents, including DS, dextran sulphate, and sodium alginate. Anionic DS was selected to synthesize hydrophobic ionic complex (ISMM-DS HIC), which was loaded into lipid nanoparticles (LA ISMM-DS LNP) by in situ complexation followed by the solvent evaporation method. 35-5-folds increase in the drug loading of hydrophilic cationic ISMM within nanoparticles was observed due to ISMM-DS HIC. The LA ISMM-DS LNP were non-hemolytic (0-2.52%), cytocompatible (80.6-47.5% cell viability), and enhanced THP-1 cellular uptake (2.3-folds higher) compared with free ISMM. The LA ISMM-DS LNP engender protracted in vivo plasma drug concentration for seven days with enhanced AUC_0-ꝏ, MRT_0-ꝏ, and t_1/2, along with reduced Cl compared with free ISMM. Interestingly, the amount of ISMM was 2.9-, 4.2- and 2.0-folds higher in target reticuloendothelial (RES) organs like liver (Kupffer cells), spleen (spleenotropic macrophages and 15% T-lymphocytes), and lymph nodes (75% T-lymphocytes), respectively in LA ISMM-DS LNP group compared with free ISMM. Furthermore, LA ISMM-DS LNP caused higher peripheral blood mononuclear cells (PBMC) infiltration with diminished toxicity and inflammation. Therefore, the in vitro and in vivo studies predicted enhanced safety and efficacy of LA ISMM-DS LNP compared with free ISMM. To conclude, successfully developed LA ISMM-DS LNP would elicit a tremendous clinical potential for treatment and prevention against trypanosomiasis.

Long-acting antiretrovirals: a new era for the management and prevention of HIV infection

The long-acting antiretroviral cabotegravir and rilpivirine combination has just received FDA, EMA and Health Canada approval. This novel drug delivery approach is about to revolutionize the therapy of people living with HIV, decreasing the 365 daily pill burden to only six intramuscular injections per year. In addition, islatravir, a first-in-class nucleoside reverse transcriptase translocation inhibitor, is intended to be formulated as an implant with a dosing interval of 1 year or more. At present, long-acting antiretroviral therapies (LA-ARTs) are given at fixed standard doses, irrespectively of the patient's weight and BMI, and without consideration for host genetic and non-genetic factors likely influencing their systemic disposition. Despite a few remaining challenges related to administration (e.g. pain, dedicated medical procedure), the development and implementation of LA-ARTs can overcome long-term adherence issues by improving patients' privacy and reducing social stigma associated with the daily oral intake of anti-HIV treatments. Yet, the current 'one-size-fits-all' approach does not account for the recognized significant inter-individual variability in LA-ART pharmacokinetics. Therapeutic drug monitoring (TDM), an important tool for precision medicine, may provide physicians with valuable information on actual drug exposure in patients, contributing to improve their management in real life. The present review aims to update the current state of knowledge on these novel promising LA-ARTs and discusses their implications, particularly from a clinical pharmacokinetics perspective, for the future management and prevention of HIV infection, issues of ongoing importance in the absence of curative treatment or an effective vaccine.

Interests of the Non-Human Primate Models for HIV Cure Research

Non-human primate (NHP) models are important for vaccine development and also contribute to HIV cure research. Although none of the animal models are perfect, NHPs enable the exploration of important questions about tissue viral reservoirs and the development of intervention strategies. In this review, we describe recent advances in the use of these models for HIV cure research and highlight the progress that has been made as well as limitations using these models. The main NHP models used are (i) the macaque, in which simian immunodeficiency virus (SIVmac) infection displays similar replication profiles as to HIV in humans, and (ii) the macaque infected by a recombinant virus (SHIV) consisting of SIVmac expressing the HIV envelope gene serving for studies analyzing the impact of anti-HIV Env broadly neutralizing antibodies. Lessons for HIV cure that can be learned from studying the natural host of SIV are also presented here. An overview of the most promising and less well explored HIV cure strategies tested in NHP models will be given.

Sub-50 nm ultra-small organic drug nanosuspension prepared by cavi-precipitation and its brain targeting potential

The purpose of this study was to show whether it is possible to prepare sub 100 nm or preferably sub-50 nm drug nanosuspension (NS) of suitable quality for intravenous administration. Furthermore, we have studied how the brain targeting potential of such small size organic NS differs from relatively bigger size NS. Two combination technologies (cavi-precipitation, H96) and a standard high-pressure homogenization (HPH) technology were used to prepare drug NS of different sizes. The cavi-precipitation process generated the smallest AmB NS, i.e., 27 nm compared to 79 nm by H96 technology and 252 nm by standard HPH technology. Dialysis of the nanosuspension in the original dispersion media was found to be the most efficient solvent removal method without negatively affecting particle size. The removal of organic solvent was found to drastically improve the stability of the formulations. The protein adsorption pattern shows that the small size NS particles obtained by the cavi-precipitation process have the potential to circulate longer in the bloodstream and have the potential to be taken up by the blood-brain barrier. The cavi-precipitation process generated ultrafine NS particles, which fulfilled the quality requirements for intravenous administration and offer a potential solution for brain targeting.

The emergence of imaging mass spectrometry in drug discovery and development: Making a difference by driving decision making

The pharmaceutical industry is a dynamic, science-driven business constantly under pressure to innovate and morph into a higher performing organization. Innovations can include the implementation of new technologies, adopting new scientific methods, changing the decision-making process, compressing timelines, or making changes to the organizational structure. The drivers for the constant focus on performance improvement are the high cost of R&D as well as the lengthy timelines required to deliver new medicines for unmet needs. Successful innovations are measured against both the quality and quantity of potential new medicines in the pipeline and the delivery to patients. In this special feature article, we share our collective experience implementing matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) technology as an innovative approach to better understand the tissue biodistribution of drugs in the early phases of drug discovery to establish pharmacokinetic-pharmacodynamic (PK-PD) relationships, as well as in the development phase to understand pharmacology, toxicology, and disease pathogenesis. In our experience, successful implementation of MALDI IMS in support of therapeutic programs can be measured by the impact IMS studies have on driving decision making in pipeline progression. This provides a direct quantifiable measurement of the return to the organization for the investment in IMS. We have included discussion not only on the technical merits of IMS study conduct but also the key elements of setting study objectives, building collaborations, data integration into the medicine progression milestones, and potential pitfalls when trying to establish IMS in the pharmaceutical arena. We categorized IMS study types into five groups that parallel pipeline progression from the earliest phases of discovery to late stages of preclinical development. We conclude the article with some perspectives on how we see MALDI IMS maintaining relevance and becoming further embedded as an essential tool in the constantly changing environment of the pharmaceutical industry.

A review of existing strategies for designing long-acting parenteral formulations: Focus on underlying mechanisms, and future perspectives

The need for long-term treatments of chronic diseases has motivated the widespread development of long-acting parenteral formulations (LAPFs) with the aim of improving drug pharmacokinetics and therapeutic efficacy. LAPFs have been proven to extend the half-life of therapeutics, as well as to improve patient adherence; consequently, this enhances the outcome of therapy positively. Over past decades, considerable progress has been made in designing effective LAPFs in both preclinical and clinical settings. Here we review the latest advances of LAPFs in preclinical and clinical stages, focusing on the strategies and underlying mechanisms for achieving long acting. Existing strategies are classified into manipulation of in vivo clearance and manipulation of drug release from delivery systems, respectively. And the current challenges and prospects of each strategy are discussed. In addition, we also briefly discuss the design principles of LAPFs and provide future perspectives of the rational design of more effective LAPFs for their further clinical translation.

Ultra-long acting prodrug of dolutegravir and delivery system - Physicochemical, pharmacokinetic and formulation characterizations

The focus of present work was to characterize ultra-long acting prodrug of dolutegravir (DTG) and develop biodegradable microparticle formulation. Palmitic acid (PA) conjugated prodrug of DTG was prepared by esterification of hydroxyl group of DTG with the carboxyl group of PA. Physicochemical properties of the prodrug was characterize by MS, NMR, FTIR, SEM, DSC, NIR-CI, pH-solubility, and solid and liquid pH-stability. Comparative solid and liquid stability was performed by storing powder DTG and DTG-Palmitate at 40 °C/75% RH for three months and liquid solution pH 2-8 at room temperature for 24 h, respectively. Pharmacokinetic evaluation was performed in white albino New Zealand rabbits by subcutaneous injection (30 mg/Kg). Poly(lactide-co-glycolide) microparticle formulation was prepared by emulsification-evaporation method and characterized for particle size distribution, shape, drug loading and in-vitro release. MS, NMR, FTIR, SEM, DSC, NIR-CI indicated formation of prodrug. Melting point of the prodrug was lower than DTG but higher than PA. Shape of DTG crystals was irregular while DTG-Palmitate crystals was fine-needle. Solid and liquid stability profiles of the prodrug were similar to DTG. Plasma half-life, area under the curve, and mean-residence time of DTG-Palmitate were 8.8, 2.3 and 14.7 folds of DTG. D₉₀ of DTG and DTG-Palmitate microparticles was 107.1 ± 2.7 and 94.3 ± 3.4 µm, respectively. The in-vitro drug release was almost complete in three weeks from DTG microparticles while it was <85% in six months from DTG-Palmitate microparticles. In conclusion, physicochemical and pharmacokinetic properties and biodegradable microparticles of the prodrug suggested that the prodrug has potential of sustaining DTG release for ultra-long period compared to DTG.

Box-Behnken design aided optimization and validation of developed reverse phase HPLC analytical method for simultaneous quantification of dolutegravir sodium and lamivudine co-loaded in nano-liposomes

A stability-indicating reversed-phase high-performance liquid chromatography method for simultaneous estimation of dolutegravir sodium and lamivudine encapsulated in the nanoliposomal formulation was developed. The chromatographic parameters namely, organic phase ratio, flow rate, and sample injection volume were selected as independent factors and were optimized by multivariate Box-Behnken design. Responses analyzed were retention time, peak area, and resolution. The optimized chromatographic method with Hypersil BDS C8 CN column as stationary phase and methanol and acetonitrile mixture and acidified Milli-Q water (pH 2.8, adjusted with 0.02% v/v orthophosphoric acid) as the mobile phase in an isocratic elution mode was validated according to parameters of International Conference on Harmonization Q1(R2) guidelines. The validated reversed-phase high-performance liquid chromatography method exhibited specificity for both dolutegravir sodium and lamivudine in the presence of degradation products as well as the liposomal matrix. This method was effectively utilized to determine the amount of drug entrapped and drug loading efficiency of dolutegravir sodium and lamivudine in a nano-liposomal formulation.

Application of solid lipid nanoparticles as a long-term drug delivery platform for intramuscular and subcutaneous administration: In vitro and in vivo evaluation

The purpose of this work was to evaluate solid lipid nanoparticles (SLNs) as a long acting injectable drug delivery platform for intramuscular and subcutaneous administration. SLNs were developed with a low (unsaturated) and high (supersaturated) drug concentration at equivalent lipid doses. The impact of the drug loading as well as the administration route for the SLNs using two model compounds with different physicochemical properties were explored for their in vitro and in vivo performance. Results revealed that drug concentration had an influence on the particle size and entrapment efficiency of the SLNs and, therefore, indirectly an influence on the C_max/dose and AUC/dose after administration to rats. Furthermore, the in vitro drug release was compound specific, and linked to the affinity of the drug compounds towards the lipid matrix and release medium. The pharmacokinetic parameters resulted in an increased t_max, t_1/2 and mean residence time (MRT) for all formulations after intramuscular and subcutaneous dosing, when compared to intravenous administration. Whereas, the subcutaneous injections performed better for those parameters than the intramuscular injections, because of the higher blood perfusion in the muscles compared with the subcutaneous tissues. In conclusion, SLNs extend drug release, need to be optimized for each drug, and are appropriate carriers for the delivery of drugs that require a short-term sustained release in a timely manner.

Excipient-Free Pure Drug Nanoparticles Fabricated by Microfluidic Hydrodynamic Focusing

Nanoprecipitation is one of the most versatile methods to produce pure drug nanoparticles (PDNPs) owing to the ability to optimize the properties of the product. Nevertheless, nanoprecipitation may result in broad particle size distribution, low physical stability, and batch-to-batch variability. Microfluidics has emerged as a powerful tool to produce PDNPs in a simple, reproducible, and cost-effective manner with excellent control over the nanoparticle size. In this work, we designed and fabricated T- and Y-shaped Si-made microfluidic devices and used them to produce PDNPs of three kinase inhibitors of different lipophilicity and water-solubility, namely imatinib, dasatinib and tofacitinib, without the use of colloidal stabilizers. PDNPs display hydrodynamic diameter in the 90-350 nm range as measured by dynamic light scattering and a rounded shape as visualized by high-resolution scanning electron microscopy. Powder X-ray diffraction and differential scanning calorimetry confirmed that this method results in highly amorphous nanoparticles. In addition, we show that the flow rate of solvent, the anti-solvent, and the channel geometry of the device play a key role governing the nanoparticle size.

Intranasal Nanoemulsions for Direct Nose-to-Brain Delivery of Actives for CNS Disorders

The treatment of various central nervous system (CNS) diseases has been challenging, despite the rapid development of several novel treatment approaches. The blood-brain barrier (BBB) is one of the major issues in the treatment of CNS diseases, having major role in the protection of the brain but simultaneously constituting the main limiting hurdle for drugs targeting the brain. Nasal drug delivery has gained significant interest for brain targeting over the past decades, wherein the drug is directly delivered to the brain by the trigeminal and olfactory pathway. Various novel and promising formulation approaches have been explored for drug targeting to the brain by nasal administration. Nanoemulsions have the potential to avoid problems, including low solubility, poor bioavailability, slow onset of action, and enzymatic degradation. The present review highlights research scenarios of nanoemulsions for nose-to-brain delivery for the management of CNS ailments classified on the basis of brain disorders and further identifies the areas that remain unexplored. The significance of the total dose delivered to the target region, biodistribution studies, and long-term toxicity studies have been identified as the key areas of future research.

Nanotechnology in pulmonary medicine

Nanotechnology in medicine—nanomedicine—is extensively employed to diagnose, treat, and prevent pulmonary diseases. Over the last few years, this brave new world has made remarkable progress, offering opportunities to address historical clinical challenges in pulmonary diseases including multidrug resistance, adverse side effects of conventional therapeutic agents, novel imaging, and earlier disease detection. Nanomedicine is also being applied to tackle the new emerging infectious diseases, including severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), influenza A virus subtype H1N1 (A/H1N1), and more recently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this review we provide both a historical overview of the application of nanomedicine to respiratory diseases and more recent cutting-edge approaches such as nanoparticle-mediated combination therapies, novel double-targeted nondrug delivery system for targeting, stimuli-responsive nanoparticles, and theranostic imaging in the diagnosis and treatment of pulmonary diseases.

Fully synthetic injectable depots with high drug content and tunable pharmacokinetics for long-acting drug delivery

Clinical studies have validated that antiretroviral (ARV) drugs can serve as an HIV pre-exposure prophylactic (PrEP) strategy. Dosing adherence remains a crucial factor determining the final efficacy outcomes, and both long-acting implants and injectable depot systems are being developed to improve patient adherence. Here, we describe an injectable depot platform that exploits a new mechanism for both formation and controlled release. The depot is a polymeric prodrug synthesized from monomers that incorporate an ARV drug tenofovir alafenamide (TAF) with degradable linkers that can be designed to control release rates. The prodrug monomers are synthetically incorporated into homopolymer or block designs that exhibit high drug weight percent (wt%) and also are hydrophobized in these prodrug segments to drive depot formation upon injection. Drug release converts those monomers to more hydrophilic pendant groups via linker cleavage, and as this drug release proceeds, the polymer chains losing hydrophobicity are then disassociated from the depot and released over time to provide a depot dissolution mechanism. We show that long-acting TAF depots can be designed as block copolymers or as homopolymers. They can also be designed with different linkers, for example with faster or slower degrading p-hydroxybenzyloxycarbonyl (Benzyl) and ethyloxycarbonyl (Alkyl) linkers, respectively. Diblock designs of p(glycerol monomethacrylate)-b-p(Alkyl-TAF-methacrylate) and p(glycerol monomethacrylate)-b-p(Benzyl-TAF-methacrylate) were first characterized in a mouse subcutaneous injection model. The alkylcarbamate linker design (TAF 51 wt%) showed excellent sustained release profiles of the key metabolite tenofovir (TFV) in skin and plasma over a 50-day period. Next, the homopolymer design with a high TAF drug wt% of 73% was characterized in the same model. The homopolymer depots with p(Alkyl-TAFMA) exhibited sustained TFV and TAF release profiles in skin and blood over 60 days, and TFV-DP concentrations in peripheral blood mononuclear cells (PBMC) were found to be at least 10-fold higher than the clinically suggested minimally EC90 protective concentration of 24 fmol/10⁶ cells. These are the first reports of sustained parent TAF dosing observed in mouse and TFV-DP in mouse PBMC. IVIS imaging of rhodamine labeled homopolymer depots showed that degradation and release of the depot coincided with the sustained TAF release. Finally, these polymers showed excellent stability in accelerated stability studies over a six-month time period, and exceptional solubility of over 700 mg/mL in the DMSO formulation solvent. The homopolymer designs have a drug reservoir potential of well over a year at mg/day dosing and may not require cold chain storage for global health and developed world long-acting drug delivery applications.

Nanosystems Applied to HIV Infection: Prevention and Treatments

Sexually-transmitted infections (STIs) are a global health concern worldwide as they cause acute diseases, infertility, and significant mortality. Among the bacterial, viral, and parasitic pathogens that can be sexually transmitted, human immunodeficiency virus (HIV) has caused one of the most important pandemic diseases, which is acquired immune deficiency syndrome (AIDS). 32.7 million people have died from AIDS-related illnesses since the start of the epidemic. Moreover, in 2019, 38 million people were living with HIV worldwide. The need to deal with this viral infection becomes more obvious, because it represents not only a problem for public health, but also a substantial economic problem. In this context, it is necessary to focus efforts on developing methods for prevention, detection and treatment of HIV infections that significantly reduce the number of newly infected people and provide a better quality of life for patients. For several decades, biomedical research has been developed allowing quick solutions through the contribution of effective tools. One of them is the use of polymers as vehicles, drug carrier agents, or as macromolecular prodrugs. Moreover, nanosystems (NSs) play an especially important role in the diagnosis, prevention, and therapy against HIV infection. The purpose of this work is to review recent research into diverse NSs as potential candidates for prevention and treatment of HIV infection. Firstly, this review highlights the advantages of using nanosized structures for these medical applications. Furthermore, we provide an overview of different types of NSs used for preventing or combating HIV infection. Then, we briefly evaluate the most recent developments associated with prevention and treatment alternatives. Additionally, the implications of using different NSs are also addressed.

Design strategies for long-acting anti-HIV pharmaceuticals

Current combination antiretroviral therapy (cART) for human immunodeficiency virus (HIV) is limited by the frequent dosing and unfavorable adherence, and the rapid appearance of resistant mutants. Thus, there is a continuous need to improve and optimize the present therapies. The clinical phase III trials of FLAIR and ATLAS, showed two-drug injectable cabotegravir (CAB) and rilpivirine (RPV) formulation is potent, safe, and tolerable in HIV-infected patients. The recent approval of cabenuva (CAB+RPV) by Health Canada is a milestone in the development of long-term therapies for HIV infection. Broadly neutralizing antibodies (bNAbs) with excellent breath and efficiency against HIV have been investigated as LA antiviral weapons. Several modern modalities capable of sustained drug release for long-term treatment and prevention of HIV infection are also in development, such as implants, vaginal rings, and nanotherapies.