Enhanced antimalalarial activity of a prolonged release in situ gel of arteether–lumefantrine in a murine model

Injectable controlled-release systems for the prevention and treatment of infectious diseases

Pharmaceutical drugs, including vaccines, pre- and post-exposure prophylactics, and chronic drug therapies, are crucial tools in the prevention and treatment of infectious diseases. These drugs have the ability to increase survival and improve patient quality of life; however, infectious diseases still accounted for more than 10.2 million deaths in 2019 before the COVID-19 pandemic. High mortality can be, in part, attributed to challenges in the availability of adequate drugs and vaccines, limited accessibility, poor drug bioavailability, the high cost of some treatments, and low patient adherence. A majority of these factors are logistical rather than technical challenges, providing an opportunity for existing drugs and vaccines to be improved through formulation. Injectable controlled-release drug delivery systems are one class of formulations that have the potential to overcome many of these limitations by releasing their contents in a sustained manner to reduce the need for frequent re-administration and improve clinical outcomes. This review provides an overview of injectable controlled drug delivery platforms, including microparticles, nanoparticles, and injectable gels, detailing recent developments using these systems for single-injection vaccination, long-acting prophylaxis, and sustained-release treatments for infectious disease.

Facile Technology for Extemporaneous Preparation of Long-Acting Injectable Microparticulate Suspensions at the Patient Side

In this study, we present an innovative and facile in situ approach for extemporaneous preparation of sterile microparticles. An amazingly simple approach, in situ technology circumvents the stability, and scale up challenges as well as sterilization issues associated with long-acting particulate systems. Monophasic preconcentrates of donepezil base (DPZ), a model drug with a biodegradable polymer poly (DL-lactide-co-glycolide) (PLGA), with stabilizer were prepared by simple solution and sterilized by filtration (0.22 micron). The sterile preconcentrates when added to aqueous dextrose solution (total volume < 3 mL) generated ready-to-inject DPZ PLGA microparticles (DPZ-PLGA-MP) with high reproducibility, entrapment efficiency (> 80%), and size ~ 80 micron. DPZ micro suspension (DPZ-MS) with high precipitation efficiency (> 90%) and size ~ 80 micron was obtained in a similar manner omitting PLGA. XRD and DSC study confirmed decreased crystallinity in the presence of PLGA. No interaction between PLGA and DPZ was evident in the FTIR study. The microparticulate dispersions exhibited good in vitro injectability when tested using the texture analyzer (force < 5 N). When evaluated using the dialysis bag method (Himedia 12-14 kDa molecular weight cutoff), both microparticulate formulations exhibited controlled release up to 1 week in vitro. Further, low burst release of ~ 10% at the end of 6 h in the ex vivo chicken muscle study proposes great promise. Our data propose the facile extemporaneous generation of microparticles as a practical and promising approach for development of long-acting injectables. This facile approach could serve as platform technology for other drug candidates.

Development of favipiravir loaded PLGA nanoparticles entrapped in in-situ gel for treatment of Covid-19 via nasal route

In 2019 the emergence of SARS-COV-2 caused pandemic situation worldwide and claimed ∼6.4 M lives (WHO 2022). Favipiravir (FAV) is recommended as a therapy for Covid-19 which belongs to BCS class III with a short half-life of 2-5.5h. Thus, the objective of current study was the development of favipiravir loaded PLGA nanoparticles (NPs) by box-behnken design. Moreover, these NPs were entrapped in thermosensitive gel to increase the permeation through nasal route. The nanoparticles exhibit particle size of 175.6 ± 2 nm with >70 ± 0.5 %EE. NPs showed PDI (0.130) and zeta potential (-17.1 mV) suggesting homogeneity and stability of NPs. DSC, XRD, and FTIR studies concluded absence of any interaction of FAV and the excipients. SEM and AFM studies demonstrated spherical morphology of NPs with smooth surface. The NPs entrapped in-situ gel showed clarity and pH 5.5-6.1. The gelation temperature of NPs dispersed in-situ gel was found in the range of 35 °C -37 °C. The gel has viscosity in range of 34592-4568 cps. The texture analysis profile of gel showed good gelling properties. Dissolution study suggested a sustained release of FAV from NPs (24h) and NPs dispersed gel (32h) as compared to FAV solution (4h). The gel showed good mucoadhesion properties (9373.9 dyne/cm²). Ex-vivo permeation through nasal mucosa of goat elucidated NPs dispersed gel demonstrated significantly higher permeation than solution and NPs. Therefore, it would be a prospective formulation to combat Covid-19 infection with high patient compliance.

Potential of nanoformulations in malaria treatment

Malaria is caused by the protozoan Plasmodium sp and affects millions of people worldwide. Its clinical form ranges from asymptomatic to potentially fatal and severe. Current treatments include single drugs such as chloroquine, lumefantrine, primaquine, or in combination with artemisinin or its derivatives. Resistance to antimalarial drugs has increased; therefore, there is an urgent need to diversify therapeutic approaches. The disease cycle is influenced by biological, social, and anthropological factors. This longevity and complexity contributes to the records of drug resistance, where further studies and proposals for new therapeutic formulations are needed for successful treatment of malaria. Nanotechnology is promising for drug development. Preclinical formulations with antimalarial agents have shown positive results, but only a few have progressed to clinical phase. Therefore, studies focusing on the development and evaluation of antimalarial formulations should be encouraged because of their enormous therapeutic potential.

Lyotropic liquid crystals for parenteral drug delivery

The necessity for long-term treatments of chronic diseases has encouraged the development of novel long-acting parenteral formulations intending to improve drug pharmacokinetics and therapeutic efficacy. Lately, one of the novel approaches has been developed based on lipid-based liquid crystals. The lyotropic liquid crystal (LLC) systems consist of amphiphilic molecules and are formed in presence of solvents with the most common types being cubic, hexagonal and lamellar mesophases. LC injectables have been recently developed based on polar lipids that spontaneously form liquid crystal nanoparticles in aqueous tissue environments to create the in-situ long-acting sustained-release depot to provide treatment efficacy over extended periods. In this manuscript, we have consolidated and summarized the various type of liquid crystals, recent formulation advancements, analytical evaluation, and therapeutic application of lyotropic liquid crystals in the field of parenteral sustained release drug delivery.

The effects of cis and trans butenedioic acid on the physicochemical behavior of lumefantrine

A study of the differences in the effects of cis (maleic acid) and trans (fumaric acid) isomers of butenedioic acid on the crystallinity, amorphous nature, and pharmaceutical behaviour of the antimalarial drug lumefantrine is provided.

Dimeric artesunate-choline conjugate micelles coated with hyaluronic acid as a stable, safe and potent alternative anti-malarial injection of artesunate

Artesunate (ARS) is the only artemisinin-based intravenous drug approved for treatment of malaria in the clinic. ARS is rapidly metabolized in vivo to short lived (∼30-45 min) but fast acting, dihydroartemisinin (DHA). The short half-life of DHA necessitates multiple dose administration to circumvent the risk of recrudescence and development of artemisinin resistance. In this work, we report a stable, safe and potent alternative artemisinin-based injectable nanocomplex consisting of dimeric artesunate-choline conjugate (dACC) micelles coated with hyaluronic acid (HA). Firstly, dACC was synthesized by one-step esterification of two artesunate molecules with 3-(dimethylamino)-1,2-propanediol followed by quaternization. After that, dACC was self-assembled into cationic nanomicelles and further coated with anionic small molecular weight HA. The HA-coated dACC nanocomplex (dACC/HA nanocomplex) has a narrow size distribution of about 30 nm. Hemolytic toxicity and cytotoxicity studies revealed a favorable bio-safety profile. Finally, in vitro and in vivo studies showed the dACC/HA nanocomplex possess superior safety and antimalarial efficacy compared to ARS. Taken together, the dACC/HA nanocomplex is a promising injectable alternative to the traditional clinically used artesunate.

Polymeric Nanoparticle Based Diagnosis and Nanomedicine for Treatment and Development of Vaccines for Cerebral Malaria: A Review on Recent Advancement

Cerebral malaria occurs due to Plasmodium falciparum infection, which causes 228 million infections and 450,000 deaths worldwide every year. African people are mostly affected with nearly 91% cases, of which 86% are pregnant women and infants. India and Brazil are the other two countries severely suffering from malaria endemicity. Commonly used drugs have severe side effects, and unfortunately no suitable vaccine is available in the market today. In this line, this review is focused on polymeric nanomaterials and nanocapsules that can be used for the development of effective diagnostic strategies, nanomedicines, and vaccines in the management of cerebral malaria. Further, this review will help scientists and medical professionals by updating the status on the development stages of polymeric nanoparticle based diagnostics, nanomedicines, and vaccines and strategies to eradicate cerebral malaria. In addition to this, the predominant focus of this review is antimalarial agents based on polymer nanomedicines that are currently in the preclinical and clinical trial stages, and potential developments are suggested as well. This review further will have an important social and commercial impact worldwide for the development of polymeric nanomedicines and strategies for the treatment of cerebral malaria.

Recent advances in targeting malaria with nanotechnology-based drug carriers

Malaria, as one of the most common human infectious diseases, remains the greatest global health concern, since approximately 3.5 billion people around the world, especially those in subtropical areas, are at the risk of being infected by malaria. Due to the emergence and spread of drug resistance to the current antimalarials, malaria-related mortality and incidence rates have recently increased. To overcome the aforementioned obstacles, nano-vehicles based on biodegradable, natural, and non-toxic polymers have been developed. Accordingly, these systems are considered as a potential drug vehicle, which due to their unique properties such as the excellent safety profile, good biocompatibility, tunable structure, diversity, and the presence of functional groups within the polymer structure, could facilitate covalent attachment of targeting moieties and antimalarials to the polymeric nano-vehicles. In this review, we highlighted some recent developments of liposomes as unique nanoscale drug delivery vehicles and several polymeric nanovehicles, including hydrogels, dendrimers, self-assembled micelles, and polymer-drug conjugates for the effective delivery of antimalarials.

Promising nanomaterials in the fight against malaria

For more than one hundred years, several treatments against malaria have been proposed but they have systematically failed, mainly due to the occurrence of drug resistance in part resulting from the exposure of the parasite to low drug doses. Several factors are behind this problem, including (i) the formidable barrier imposed by the Plasmodium life cycle with intracellular localization of parasites in hepatocytes and red blood cells, (ii) the adverse fluidic conditions encountered in the blood circulation that affect the interaction of molecular components with target cells, and (iii) the unfavorable physicochemical characteristics of most antimalarial drugs, which have an amphiphilic character and can be widely distributed into body tissues after administration and rapidly metabolized in the liver. To surpass these drawbacks, rather than focusing all efforts on discovering new drugs whose efficacy is quickly decreased by the parasite's evolution of resistance, the development of effective drug delivery carriers is a promising strategy. Nanomaterials have been investigated for their capacity to effectively deliver antimalarial drugs at local doses sufficiently high to kill the parasites and avoid drug resistance evolution, while maintaining a low overall dose to prevent undesirable toxic side effects. In recent years, several nanostructured systems such as liposomes, polymeric nanoparticles or dendrimers have been shown to be capable of improving the efficacy of antimalarial therapies. In this respect, nanomaterials are a promising drug delivery vehicle and can be used in therapeutic strategies designed to fight the parasite both in humans and in the mosquito vector of the disease. The chemical analyses of these nanomaterials are essential for the proposal and development of effective anti-malaria therapies. This review is intended to analyze the application of nanomaterials to improve the drug efficacy on different stages of the malaria parasites in both the human and mosquito hosts.

Choline and PEG dually modified artemether nano delivery system targeting intra-erythrocytic Plasmodium and its pharmacodynamics in vivo

OBJECTIVE

The choline derivative (CD) and polyethylene-glycol (PEG) dually modified artemether (ARM) nanostructured lipid carriers (CD-PEG-ARM-NLC) have been designed to prolong the circulation of ARM in blood, as well as to develop targeting for new permeability pathways (NPPs) and erythrocyte choline carriers (ECCs) that are expressed on the Plasmodium-infected erythrocyte membrane.

SIGNIFICANCE

The CD-PEG-ARM-NLC constructed in this study was found to be able to target endoerythrocytic Plasmodium by increasing the drug concentration and residence time in the infected erythrocytic microenvironment and minimizing toxicity and side effects.

METHODS

CD-PEG-ARM-NLC was prepared using high-pressure homogenization followed by physicochemical characterization. The targeting ability of CD-PEG-NLC to infected erythrocytes probed by coumarin-6 was investigated by using fluorescence microscopy imaging. The SYBR Green I assay for parasite nucleic acid was adapted in order to assess the efficacy of inhibition against parasite growth in vitro. The antimalarial activity of ARM-loaded NLCs was evaluated by a Pearson four-day suppressive test in Pyy265BY-bearing mice.

RESULTS

In vitro imaging indicated that the intracellular delivery of CD-PEG-ARM-NLC was efficiently taken up by the infected erythrocytes via ECCs and NPPs, which could be inhibited by addition of furosemide (an inhibitor of NPPs) and excessive choline (native substrate of ECCs). Moreover, in vitro and in vivo studies that evaluated antimalarial activity suggested that CD-PEG-ARM-NLC exhibited higher antimalarial activity in comparison to ARM-NLC and PEG-ARM-NLC.

CONCLUSION

These findings suggested that choline and PEG dually modified NLC could be promising preparations for the production of hydrophobic antimalarial drugs, particularly for ARM.

A single dose of in situ gel formulation of antimalarial drug chloroquine phosphate as a sustained prophylactic candidate for COVID-19

In the ongoing COVID-19 outbreak, a prophylactic drug is strongly needed to stop the spread of this disease. Chloroquine (CQ) has been proposed as a prophylactic for individuals who are likely to be exposed to the virus. This study aimed to study the ability of CQ to act as a prophylactic treatment for susceptible people. The pharmacokinetic profiles of in situ gel and free CQ phosphate were determined using high-performance liquid chromatography. The effects of both formulations were examined on both liver and kidney functions. CQ levels were sustained in the plasma of both free and in situ gel-treated groups. Thus, our study shows that the in situ gel of CQ provides sustained release of CQ that is given only as a single dose. However, it should be used cautiously in patients with liver or kidney dysfunction.

Study towards improving artemisinin-based combination therapies

Covering: Up to 2020 Artemisinin has made a significant contribution towards global malaria control since its initial discovery. Countless lives have been saved by this unique and miraculous molecule. In 2006, artemisinin-based combination therapies (ACTs) were recommended by the World Health Organization (WHO) as the first-line treatment for uncomplicated malaria infection and have since remained as the mainstays of the antimalarial treatment. Even so, substantial efforts to pursue better curative effects for the treatment of malaria have never ceased, particularly with regards to the circumstances surrounding the appearance of delayed clearance of malaria parasites by 3 day ACT treatments in South-East Asian countries. Strategies to further optimize artemisinin-based therapies, including synthesizing better artemisinin derivatives, developing advanced drug delivery systems, and diversifying artemisinin partner drugs, have been proposed over the past few years. Here, we provide an updated account of the continuous efforts in improving ACTs for better efficacy in curing malarial infection.

Nanoemulsion composed of 10-(4,5-dihydrothiazol-2-yl)thio)decan-1-ol), a synthetic analog of 3-alkylpiridine marine alkaloid: development, characterization, and antimalarial activity

Malaria treatment is based on a reduced number of antimalarial drugs, and drug resistance has emerged, leading to the search for new antimalarial drugs incorporated into pharmaceutical formulations. In this study, 10-(4,5-dihydrothiazol-2-yl)thio)decan-1-ol) (thiazoline), a synthetic analog of 3-alkylpiridine marine alkaloid, and a potent antimalarial substance, was incorporated into O/W nanoemulsion. This formulation was prepared by a 2³ factorial design. It was characterized by globule diameter, polydispersity index, zeta potential, encapsulation efficiency, in vitro thiazoline release at pH 2 and 6.86, and accelerated stability. In vitro and in vivo antimalarial activity was determined against P. falciparum and P. berghei, respectively. Thiazoline nanoemulsion showed 248.8 nm of globule diameter, 0.236 of polydispersity index, -38.5 mV of zeta potential, 96.92% encapsulation efficiency, and it was stable for 6 months. Thiazoline release profiles differed in acidic and neutral media, but in both cases, the nanoemulsion controlled and prolonged the thiazoline delivery. Thiazoline nanoemulsion exerted in vitro antimalarial activity against the parasite (IC₅₀ = 1.32 µM), and it significantly reduced the in vivo parasitemia for 8 days without increasing the survival time of animals. Therefore, the thiazoline nanoemulsion represents a strategy to treat malaria combining an antimalarial candidate and a new nanocarrier.

Combination Therapy Strategies for the Treatment of Malaria

Malaria is a vector- and blood-borne infection that is responsible for a large number of deaths around the world. Most of the currently used antimalarial therapeutics suffer from drug resistance. The other limitations associated with the currently used antimalarial drugs are poor drug bioavailability, drug toxicity, and poor water solubility. Combination therapy is one of the best approaches that is currently used to treat malaria, whereby two or more therapeutic agents are combined. Different combination therapy strategies are used to overcome the aforementioned limitations. This review article reports two strategies of combination therapy; the incorporation of two or more antimalarials into polymer-based carriers and hybrid compounds designed by hybridization of two antimalarial pharmacophores.