Free Drug Solution Research Articles

Curcumin-loaded gold nanoparticles with enhanced antibacterial efficacy and wound healing properties in diabetic rats

Diabetic wounds pose a significant global health challenge. Although curcumin exhibits promising wound healing and antibacterial properties, its clinical potential is limited by low aqueous solubility, and poor tissue penetration. This study aimed to address these challenges and enhance the wound healing efficacy of curcumin by loading it onto gold nanoparticles (AuNPs). The properties of the AuNPs, including particle size, polydispersity index (PDI), zeta potential, percent drug entrapment efficiency (%EE) and UV–Vis spectra were significantly influenced by the curcumin/gold chloride molar ratio used in the synthesis of AuNPs. The optimal formulation (F2) exhibited the smallest particle size (41.77 ± 6.8 nm), reasonable PDI (0.59 ± 0.17), high %EE (94.43 ± 0.25 %), a moderate zeta potential (−8.44 ± 1.69 mV), and a well-defined surface Plasmon resonance peak at 526 nm. Formulation F2 was incorporated into Pluronic® F127 gel to facilitate its application to the skin. Both curcumin AuNPs solution and gel showed sustained drug release and higher skin permeation parameters compared with the free drug solution. AuNPs significantly enhanced curcumin’s antibacterial efficacy by lowering the minimum inhibitory concentrations and enhancing antibacterial biofilm activity against various Gram-positive and Gram-negative bacterial strains. In a diabetic wound rat model, AuNPs-loaded curcumin exhibited superior wound healing attributes compared to the free drug. Specifically, it demonstrated improved wound healing percentage, reduced wound oxidative stress, increased wound collagen deposition, heightened anti-inflammatory effects, and enhanced angiogenesis. These findings underscore the potential of AuNPs as efficacious delivery systems of curcumin for improved wound healing applications.

Formulation and Characterization of Gabapentin-Loaded Bigel For Transpinal Delivery to Brain

In this research, the focus was on the design and evaluation of novel two-phase systems known as bigels (BGs) for the transpinal (TS) drug delivery of gabapentin. BGs combine the advantages of hydrogels and organogels while mitigating the drawbacks of individual gels. The formulation involved preparing hydrogels and organogels using carbopol 940 in varying concentrations, which were later combined in a 1:1 ratio to produce BGs. The Fourier-transform infrared spectroscopy (FTIR) analysis indicated the interaction between the drug and polymer was nil. The formulated BG formulations underwent comprehensive characterization, including assessments of physical appearance, pH, viscosity, swelling index, spreadability, drug content, in-vitro release, ex-vivo permeation, skin irritation, and antiepileptic activity. Formulation B5 emerged as the optimized formulation based on various evaluation parameters. Skin irritation studies demonstrated compatibility with the skin, showing no adverse reactions. In antiepileptic activity, rats receiving gabapentin BG via the TS route exhibited a significant reduction in convulsion duration compared to control groups that received BG without the drug or free drug solution orally. Conclusively, the study suggests that the developed BGs containing gabapentin, when applied through the TS route on the back of the neck, hold promise for reaching the brain effectively. This method presents a potential avenue for enhanced drug delivery in the control of epilepsy.

Enhancement of octreotide antiproliferative activity by PEGylated PAMAM dendrimers delivery

AbstractPEGylated PAMAM dendrimers (PEG‐PAMAM) are well‐characterized biomaterials with still unexplored applications as carriers of drugs acting via membrane receptors, such as octreotide. This work confirmed the safety and negligible internalization capacity of fourth‐generation 50%‐PEG‐PAMAM in HEK‐293 cells, to then assessed their supramolecular binding to octreotide through tryptophan quenching experiments and Gaussian‐accelerated molecular dynamics (GaMD) simulations. Tryptophan quenching showed that PEG‐PAMAM binds octreotide with a Kbind of 6 × 106 M−1 and a complex stoichiometry of 1:1.4, unlike native PAMAM. GaMD simulations revealed that octreotide binds at the outer PEG shell of PEG‐PAMAM, potentially hindering the drug from proteolytic degradation and enabling its release at a membrane level. Viability experiments on HeLa, PC‐12, and HEK‐293 cells incubated with increasing concentrations of octreotide in free drug solutions and equimolar mixtures with PEG‐PAMAM confirmed that the PEGylated dendrimer acts as an efficient supramolecular carrier for octreotide and enhances the antiproliferative effects of the drug. Our findings highlight a novel facet for PEG‐PAMAM dendrimers as macromolecular vehicles for peptide or non‐peptide drugs acting via membrane receptor sites.

Electrochemical Characterization of the Encapsulation and Release of 5-Fluorouracil in Nanocarriers Formed from Soy Lecithin Vesicles.

5-Fluorouracil (5-FU) is an antineoplastic agent known for its low bioavailability and limited cellular penetration, often resulting in adverse effects on healthy cells. Thus, finding vehicles that enhance bioavailability, enable controlled release, and mitigate adverse effects is crucial. The study focuses on encapsulating 5-FU within soy lecithin vesicles (SLVs) and assessing its impact on the carrier's properties and functionality. Results show that incorporating 5-FU does not affect SLVs' size or polydispersity, even postlyophilization. Liberation of 5-FU from SLVs requires system disruption rather than spontaneous release, with an encapsulation efficiency of approximately 43% determined using Square Wave Voltammetry. Cytotoxicity assays on colorectal cancer cells reveal SLV-based delivery's significant efficacy, surpassing free drug solution effects with 45% cell viability after 72 h vs 73% viability. The research addresses 5-FU's limited bioavailability by creating a biocompatible nanocarrier for efficient drug delivery, highlighting SLVs as promising for targeted cancer therapy due to sustained antiproliferative effects and improved cellular uptake. The study underscores the importance of tailored drug delivery systems in enhancing therapeutic outcomes and suggests SLV/5-FU formulations as a potential advancement in cancer treatment strategies.

Improving the stability and transdermal permeability of phycocyanin loaded cubosomes

Instability and low transdermal permeability of protein antioxidants are major obstacles to resist oxidative stress in transdermal drug delivery system. To overcome these shortcomings, cubosomes were developed as an advanced transdermal delivery system to improve stability and transdermal absorption of the model antioxidant phycocyanin in this study. Glyceryl monooleate and poloxamer 407 (P407) were used to prepare cubosomes as carrier matrix and stabilizer, respectively. Phycocyanin loaded cubosomes (PC-cubosomes) were prepared by the emulsification and homogenization method. A 33 full factorial design was used to optimize the cubosome formulations. The final optimal PC-cubosomes possessed an average particle size of 183.2 ± 0.5 nm and a negative surface charge as well as achieved a high encapsulation efficiency of 87.2% ± 2.7%. PC-cubosomes appeared as nano-sized and well-shaped spheres with highly ordered cubical structures. The residual amount of phycocyanin in PC-cubosomes was 3-fold higher than that in the free drug solution after 10 days ultraviolet radiation exposure. In vitro release kinetics of phycocyanin from PC-cubosomes fitted to the Higuchi kinetic model, indicating that phycocyanin released from cubosomes mainly attributed to drug diffusion and dissolution. PC-cubosomes also exhibited higher permeability (39.79 μg⋅cm−2⋅hour−1) across the rat skin than phycocyanin solution (16.33 μg⋅cm−2⋅hour−1). Furthermore, PC-cubosomes were easily taken up by keratinocytes, thereby achieving a prolonged anti-oxidative stress effect. These results therefore suggested that cubosomes could be a promising transdermal delivery system to improve the stability and transdermal permeability of phycocyanin.

An Artificial Gut/Absorption Simulator: Understanding the Impact of Absorption on In Vitro Dissolution, Speciation, and Precipitation of Amorphous Solid Dispersions.

Upon dissolution, amorphous solid dispersions (ASDs) of poorly water-soluble compounds can generate supersaturated solutions consisting of bound and free drug species that are in dynamic equilibrium with each other. Only free drug is available for absorption. Drug species bound to bile micelles, polymer excipients, and amorphous and crystalline precipitate can reduce the drug solute's activity to permeate, but they can also serve as reservoirs to replenish free drug in solution lost to absorption. However, with multiple processes of dissolution, absorption, and speciation occurring simultaneously, it may become challenging to understand which processes lead to an increase or decrease in drug solution concentration. Closed, nonsink dissolution testing methods used routinely, in the absence of drug removal, allow only for static equilibrium to exist and obscure the impact of each drug species on absorption. An artificial gut simulator (AGS) introduced recently consists of a hollow fiber-based absorption module and allows mass transfer of the drug from the dissolution media at a physiological rate after tuning the operating parameters. In the present work, ASDs of varying drug loadings were prepared with a BCS-II model compound, ketoconazole (KTZ), and hypromellose acetate succinate (HPMCAS) polymer. Simultaneous dissolution and absorption testing of the ASDs was conducted with the AGS, and simple analytical techniques were utilized to elucidate the impact of bound drug species on absorption. In all cases, a lower amount of crystalline precipitate was formed in the presence of absorption relative to the nonsink dissolution "control". However, formation of HPMCAS-bound drug species and crystalline precipitate significantly reduced KTZ absorption. Moreover, at high drug loading, inclusion of an absorption module was shown to enhance ASD dissolution. The rank ordering of the ASDs with respect to dissolution was significantly different when nonsink dissolution versus AGS was used, and this discrepancy could be mechanistically elucidated by understanding drug dissolution and speciation in the presence of absorption.

Non-invasive peptides delivery using chitosan nanoparticles assembled via scalable microfluidic technology

The delivery of peptides via non-invasive administration routes remains a challenge to be addressed. In this regard, chitosan nanoparticles (CS NPs) have shown promise. However, their current batch preparation methods (ionotropic gelation, polyelectrolyte complexing, emulsification solvent diffusion or micro emulsification) have proven difficult to scale up. Here, we established a microfluidic-assisted ionotropic gelation method for the manufacturing of CS NPs, ionically crosslinked with sodium tripolyphosphate (TPP), and loaded with a model peptide, Argireline. The microfluidic process was optimized through a design of experiments approach. CS concentration and pH have the greatest effect on particle size, while CS and TPP concentrations and pH on PDI. The optimum formulation was successfully loaded with the peptide (90 % EE) and characterized by a size of 186.0 ± 1.0 nm and a PDI of 0.440 ± 0.002. Subsequently, Argireline-loaded CS-TPP NPs suspension was converted into a gel for a potential topical application, considering the non-toxic, biocompatible, and biodegradable properties of the components used in the formulation. The NPs gel demonstrated appropriate mechanical properties for Argireline transdermal delivery, along with improved control over its release and enhanced skin permeation for up to 48 h, compared to NPs suspension and free drug solution. Hence, this study demonstrated that the microfluidic-assisted ionotropic gelation method could be an easy-scalable platform for the manufacturing of peptide-loaded CS-TPP NPs which could be potentially applied for the transdermal delivery of biologics.

Quality-by-design-engineered mitochondrial targeted nanoparticles for glioblastoma therapy.

Glioblastoma (GB, IDH-wildtype) constitutes the most aggressive primary malignant neoplasm with limited treatment modalities due to the blood-brain barrier (BBB) often restricting drug delivery. It also has an overall low survival rate with no curative solution, reinforcing the need for innovative formulation development for effective management of GB. This study explores a novel approach using triphenylphosphonium (TPP+)-conjugated chitosan nanoparticles for targeted mitochondrial delivery of temozolomide (TMZ) to GB cells. The conjugated nanoparticles were designed to leverage chitosan's biocompatibility and TPP's mitochondrial targeting ability. TMZ-loaded chitosan nanoparticles were systematically developed and optimized employing a Quality-by-Design (QbD) approach with a screening of factors (Taguchi design) followed by optimization (Box-Behnken design). The optimized nanoparticles had an average particle size of 138.1 ± 5 nm, PDI of 0.242 ± 0.04, and entrapment efficiency of 93.59 ± 3%. Further, a conjugate chitosan-TPP+ (CS-TPP+) was synthesized and validated, employing varied techniques such as NMR, FTIR, HPLC, zeta potential, and EDAX analysis. In vitro drug release in pH 5 phosphate buffer showed a sustained release for nanoparticulate formulations compared to the free drug solution further indicating that conjugation did not alter the release pattern of nanoparticles. With regards to intranasal delivery of the formulation, an ex vivo study carried out on goat nasal mucosa demonstrated greater retention of conjugated chitosan nanoparticles on nasal mucosa than free drug solution, and a mucin interaction study also corroborated this finding. In vitro cell line studies indicated nanoparticles' cytotoxic potential compared to TMZ solution. Overall, this study highlights the potential of TPP+-conjugated chitosan nanoparticles developed strategically for the targeted delivery of TMZ to mitochondria.

Co-delivering irinotecan and imiquimod by pH-responsive micelle amplifies anti-tumor immunity against colorectal cancer

Irinotecan (IRT), a classic clinical chemotherapeutic agent for treating colorectal cancer, has been found to induce immunogenic cell death (ICD) while exerting cytotoxicity in tumor cells. This effect is likely to be amplified in combination with immune modulators. Unfortunately, free drugs without targeting capacity would receive poor outcomes and strong side effects. To address these issues, in this work, an acid-sensitive micelle based on an amphiphilic poly(β-amino ester) derivative was constructed to co-deliver IRT and the immune adjuvant imiquimod (IMQ), termed PII. PII kept stable under normal physiological conditions. After internalization by tumor cells, PII dissociated in acidic lysosomes and released IRT and IMQ rapidly. In the CT26 tumor mouse model, PII increased the intra-tumoral SN38 (the active metabolite of IRT) and IMQ concentrations by up to 9.39 and 3.44 times compared with the free drug solution. The tumor inhibition rate of PII achieved 87.29%. This might profit from that IRT induced ICD, which promoted dendritic cells (DCs) maturation and intra-tumoral infiltration of CD8+ T cells. In addition, IMQ enhanced the antigen presenting ability of DCs and stimulated tumor associated macrophages to secrete tumor-killing cytokines. PII provided an effective strategy to combat colorectal cancer by synergy of chemotherapy and immunoregulation.

Anti-CD4 antibody and dendrimeric peptide based targeted nano-liposomal dual drug formulation for the treatment of HIV infection

AimsDevelopment and characterization of LAM and DTG loaded liposomes conjugated anti-CD4 antibody and peptide dendrimer (PD2) to improve the therapeutic efficacy and to achieve targeted treatment for HIV infection. Main methodsA 2-level full factorial design was used to optimize the preparation of dual drug loaded liposomes. Optimized dual drug loaded ligand conjugated liposomes were assessed for their cytotoxicity and cell internalization on TZM-bl cells. Anti-HIV efficiency of the dual drug loaded liposomes were screened for their inhibitory potential in TZM-bl cells and the activities were confirmed using Peripheral Blood Mononuclear Cells (PBMCs). Key findingsThe particle size of the optimized dual drug-loaded liposomes was 133.7 ± 4.04 nm, and the spherical morphology of the liposomes was confirmed by TEM analysis. The entrapment efficiency was 34 ± 4.9 % and 54 ± 1.8 % for LAM and DTG, respectively, and a slower in vitro release of LAM and DTG was observed when entrapped into liposomes. The cytotoxicity of the dual drug loaded liposomes was similar to the cytotoxicity of free drug solutions. Conjugation of anti-CD4 antibody and PD2 did not significantly influence the cytotoxicity but it enhanced the uptake of liposomes into the cells. Conjugated dual drug loaded liposomes exhibited better HIV inhibition with lower IC50 values (0.0003 ± 0.0002 μg/mL) compared to their free drug solutions (0.002 ± 0.001 μg/mL). The liposomal formulations have shown similar activities in both screening and confirmatory cell-based assays. SignificanceThe results demonstrated the cell targeting ability of dual drug loaded liposomes conjugated with anti-CD4 antibody and peptide dendrimer. Conjugated liposomes also improved anti-HIV efficiency of LAM and DTG.

Simultaneous Intranasal Codelivery of Donepezil and Memantine in a Nanocolloidal Carrier: Optimization, Pharmacokinetics, and Pharmacodynamics Studies.

This work focuses on developing nanoemulsions using a low-energy emulsification method for the codelivery of donepezil and memantine in one dosage form intended to be administered via the intranasal route for enhanced brain delivery. The nanoemulsion formulation was prepared using a low emulsification technique and characterized using various microscopy and nasal ciliotoxicity studies. The safe nanoemulsion was intended for preclinical pharmacokinetics with brain distribution and pharmacodynamics in a scopolamine-induced murine model. The formulated nanoemulsion was 16 nm in size, with a zeta potential of -7.22 mV, and exhibited a spherical shape. The brain concentration of IN-administered NE for DPZ and MEM was ∼678 and 249 ng/mL after 15 min. This concentration is more than 2 times higher in amount when compared with NE administered via PO, free drug solution administered via IN and PO route both. However, the plasma concentration of IN-administered NE for DPZ and MEM was ∼3 and 28 ng/mL after 15 min. In pharmacodynamic studies, the efficacy of NE administered via the IN route was higher when compared with other groups in neurobehavioral, biochemical estimation, and gene expression studies. The results suggest that the IN route can be explored in the future for the delivery of actives via nanocolloidal carriers in the brain for neurological disorders and can serve as promising alternatives for conventional dosage forms and routes.

Exploring Penetration Ability of Carbonic Anhydrase Inhibitor-Loaded Ultradeformable Bilosome for Effective Ocular Application.

Brinzolamide is an effective carbonic anhydrase inhibitor widely used in glaucoma therapy but limits its application due to inadequate aqueous solubility and permeability. The aim of the present research work is the development and characterization of brinzolamide-loaded ultradeformable bilosomes to enhance the corneal permeation of the drug. These ultradeformable bilosomes were prepared by ethanol injection method and evaluated for physicochemical properties, particle size, morphology, drug release, ultra-deformability, corneal permeation, and irritation potential. The optimized formulation exhibited an average particle size of 205.4 ± 2.04nm with mono-dispersity (0.109 ± 0.002) and showed entrapment efficiency of 75.02 ± 0.017%, deformability index of 3.91, and release the drug in a sustained manner. The brinzolamide-loaded ultradeformable bilosomes released 76.29 ± 3.77% of the drug in 10h that is 2.25 times higher than the free drug solution. The bilosomes were found non-irritant to eyes with a potential irritancy score of 0 in Hen's egg-chorioallantoic membrane assay. Brinzolamide-loaded ultradeformable bilosomes showed 83.09 ± 5.1% of permeation in 6h and trans-corneal permeability of 8.78 ± 0.14cm/h during the ex vivo permeation study. The acquired findings clearly revealed that the brinzolamide-loaded ultradeformable bilosomes show promising output and are useful in glaucoma therapy.

In vitro dissolution/permeation tools for amorphous solid dispersions bioavailability forecasting II: Comparison and mechanistic insights

Along with the increasing demand for complex formulations comes the need for appropriate in vitro methodologies capable of predicting their corresponding in vivo performance and the mechanisms controlling the drug release which can impact on in vivo drug absorption. In vitro dissolution-permeation (D/P) methodologies that can account for the effects of enabling formulations on the permeability of drugs are increasingly being used in performance ranking during early development stages. This work comprised the application of two different cell-free in vitro D/P setups: BioFLUX™ and PermeaLoop™ to evaluate the dissolution-permeation interplay upon drug release from itraconazole (ITZ)- HPMCAS amorphous solid dispersions (ASDs) of different drug loads. A solvent-shift approach was employed, from a simulated gastric environment to a simulated intestinal environment in the donor compartment. PermeaLoop™ was then combined with microdialysis sampling to separate the dissolved (free) drug from other species present in solution, like micelle-bound drug and drug-rich colloids, in real time. This setup was applied to clarify the mechanisms for drug release and permeation from these ASDs. In parallel, a pharmacokinetic study (dog model) was conducted to assess the drug absorption from these ASDs and to compare the in vivo results with the data obtained from each in vitro D/P setup, allowing to infer which would be the most adequate setup for ASD ranking. Even though both D/P systems resulted in the same qualitative ranking, BioFLUX™ overpredicted the difference between the in vivo AUC of two ASDs, whereas PermeaLoop™ permeation flux resulted in a good correlation with the AUC observed in pharmacokinetic studies (dog model) (R2 ≈ 0.98). Also, PermeaLoop™ combined with a microdialysis sampling probe clarified the mechanisms for drug release and permeation from these ASDs. It demonstrated that the free drug was the only driving force for permeation, while the drug-rich colloids kept permeation active for longer periods by acting as drug reservoirs and maintaining constant high levels of free drug in solution, which are then immediately able to permeate. Hence, the data obtained points BioFLUX™ and PermeaLoop™ applications to different momentums in the drug product development pipeline: while BioFLUX™, an automated standardized method, poses as a valuable tool for initial ASD ranking during the early development stages, PermeaLoop™ combined with microdialysis sampling allows to gain mechanistic understanding of the dissolution-permeation interplay, being crucial to fine tune and identify leading ASD candidates prior to in vivo testing.

Design of mesalamine loaded micro-particles: Preparation, in vitro and in-vivo characterization

The goal of this study was to develop mesalamine (MS) microparticles that could be ingested by the colon without first passing via the stomach and small intestines. Without resorting to the time-consuming and laborious double emulsion solvent diffusion method, microparticles were successfully fabricated using the Box-Behnken Design method. Microparticle production was optimized, and the effects of many parameters were analyzed (X1: Eudragit S100, X2: Span 80 and X3: agitation speed). Using the Box-Behnken design (BBD), we compared the chosen optimized microparticles to the pure drug solution utilizing in vivo pharmacokinetic study for particle size (Y1), entrapment efficiency (Y2), and drug-release (Y3). It was simple to create spherical, free-flowing, smooth-surfaced microparticles with a zeta potential of −36.52 mV and a size distribution of 264.35 ± 6.28–652.34 ± 6.49 nm. Coefficients of 264.35 ± 6.28–652.34 ± 6.49%, 42.31 ± 2.43–89.74 ± 2.17%, and 52.31 ± 0.43–93.51 ± 0.33% from a quadratic model best fit the observed values of dependent variables. Formulation F4 was selected as the best option because it prevented the drug from being released in the upper GIT before it was ready and instead released it only in the colon, where the pH is optimal. The formulation had a particle size of 266.597 μm, an entrapment efficiency of 93.735%, a cumulative drug release of 95.578 percent, and a desirability factor of 0.998. In comparison to drug solution pharmacokinetics, microparticle pharmacokinetics showed a 6.35-fold decrease in Cmax and MS with an appropriately increased half-life of 8.13 h. (13.67 and 3.46). This enhanced bioavailability of MS released from microparticles is probably due to an increase in the half-life, mean residence time (MRT), and area under the concentration–time curve (AUC0-24) of MS. Over a long length of time with no increase in plasma MS level, it became clear that the novel method of MS-loaded microparticles would provide successful therapy for ulcerative colitis. A pharmacodynamic study found that mesalamine-loaded microparticles dramatically decreased colon edema, necrosis, and bleeding compared to free drug solution. Results from this study suggest that mesalamine-loaded microparticles may be an effective pharmaceutical delivery strategy for the management of ulcerative colitis.

PH-sensitive liposomes bearing a chemotherapeutic agent and a natural apoptosis modulator for effective intracellular delivery to the solid tumor.

The intracellular delivery of the drug to the solid tumor is a major challenge in the treatment of solid tumors. This project aims to increase cytosolic drug delivery using the endosomal escape of drugs. Topotecan (TPT) and capsaicin were used for the treatment of solid tumors. The pH-dependent conversion of active lactone form to inactive carboxylic form is a major problem of TPT that limits its therapeutic use. Liposomal encapsulation of TPT improved the stability of active lactone form and increased the therapeutic efficacy of TPT. Endosomal degradation of liposomes may reduce the content in the target cells. To solve these problems, pH-sensitive liposomes (pSLPs) were developed which improved the intracellular drug delivery by the endosomal escape of drugs. The liposomes (LPs) bearing the drug(s) were prepared using the cast film method and optimized for various formulation and process variables using the Design-Expert 7 software by employing the Box-Behnken design (BBD). The developed hyaluronic acid (HA)-conjugated pSLPs (HA-pSLPs) displayed a vesicle size of 166.5 ± 2.31nm, zeta potential - 30.53 ± 0.91, and entrapment efficiency of 44.39 ± 1.78%, and 73.48 ± 2.15% for TPT and CAP, respectively. HA-pSLPs displayed better cytotoxicity in comparison to free drugs either single or in combination on the MCF-7 cell line. The apoptosis and cellular uptake of HA-pSLPs were increased ⁓ 4.45-fold and ⁓ 6.95-fold as compared to unconjugated pSLPs, respectively. The pharmacokinetic studies in Balb/c mice demonstrated that HA-pSLPs increased the half-life, MRT, and AUC in comparison to the free drug solution. The HA-pSLPs formulation has shown remarkable tumor regression as compared to PpSLPs, pSLPs, and free drug combinations. These results demonstrated that TPT- and CAP-loaded HA-pSLPs offer a potential platform for targeted drug delivery to solid tumors.

Pyruvate-conjugation of PEGylated liposomes for targeted drug delivery to retinal photoreceptors

Despite several promising candidates, there is a paucity of drug treatments available for patients suffering from retinal diseases. An important reason for this is the lack of suitable delivery systems that can achieve sufficiently high drug uptake in the retina and its photoreceptors. A promising and versatile method for drug delivery to specific cell types involves transporter-targeted liposomes, i.e., liposomes surface-coated with substrates for transporter proteins highly expressed on the target cell. We identified strong lactate transporter (monocarboxylate transporter, MCT) expression on photoreceptors as a potential target for drug delivery vehicles. To evaluate MCT suitability for drug targeting, we used PEG-coated liposomes and conjugated these with different monocarboxylates, including lactate, pyruvate, and cysteine. Monocarboxylate-conjugated and dye-loaded liposomes were tested on both human-derived cell-lines and murine retinal explant cultures. We found that liposomes conjugated with pyruvate consistently displayed higher cell uptake than unconjugated liposomes or liposomes conjugated with lactate or cysteine. Pharmacological inhibition of MCT1 and MCT2 reduced internalization, suggesting an MCT-dependent uptake mechanism. Notably, pyruvate-conjugated liposomes loaded with the drug candidate CN04 reduced photoreceptor cell death in the murine rd1 retinal degeneration model while free drug solutions could not achieve the same therapeutic effect. Our study thus highlights pyruvate-conjugated liposomes as a promising system for drug delivery to retinal photoreceptors, as well as other neuronal cell types displaying high expression of MCT-type proteins.

Effective loading of incompatible drugs into nanosized vesicles: a strategy to allow concurrent administration of furosemide and midazolam in simulated clinical settings

The current study aims to assess the use of nanocarriers to limit drug incompatibilities in clinical settings, and thus eliminating serious clinical consequences (e.g., catheter obstruction and embolism), and enhancing in vivo bioavailability and efficacy. As a proof-of-concept, the impact of loading well-documented physically incompatible drugs (i.e., furosemide and midazolam) into nanosized vesicles on in vitro stability and in vivo bioavailability of the two drugs was investigated. Furosemide and midazolam were loaded into nanosized spherical vesicles at high entrapment efficiency (ca. 62–69%). The drug-loaded vesicles demonstrated a sustained drug release patterns, high physical stability and negligible hemolytic activity. Physical incompatibility was assessed by exploiting microscopic technique coupled with image processing and analysis, dynamic light scattering and laser Doppler anemometry. Incorporation of drugs separately inside the nanosized vesicles dramatically decreased size and number of the precipitated particles. In vivo, the niosomal drug mixture demonstrated a significant improvement in pharmacokinetic profiles of furosemide and midazolam compared to the mixed free drug solutions, as evidenced by their longer circulation half-lives and higher area under the plasma-concentration time curves of both drugs. Nanocarriers could provide an auspicious strategy for circumventing drug incompatibilities, thus reducing adverse reactions, hospitalization period and improving therapeutic outcomes.

Injectable Polypeptide Hydrogel Depots Containing Dual Immune Checkpoint Inhibitors and Doxorubicin for Improved Tumor Immunotherapy and Post-Surgical Tumor Treatment

In this work, we developed a strategy for local chemo-immunotherapy through simultaneous incorporation of dual immune checkpoint blockade (ICB) antibodies, anti-cytotoxic T-lymphocyte-associated protein 4 (aCTLA-4) and anti-programmed cell death protein 1 (aPD-1), and a chemotherapy drug, doxorubicin (Dox), into a thermo-gelling polypeptide hydrogel. The hydrogel encapsulating Dox or IgG model antibody showed sustained release profiles for more than 12 days in vitro, and the drug release and hydrogel degradation were accelerated in the presence of enzymes. In comparison to free drug solutions or hydrogels containing Dox or antibodies only, the Dox/aCTLA-4/aPD-1 co-loaded hydrogel achieved improved tumor suppression efficiency, strengthened antitumor immune response, and prolonged animal survival time after peritumoral injection into mice bearing B16F10 melanoma. Additionally, after injection of Dox/aCTLA-4/aPD-1 co-loaded hydrogel into the surgical site following tumor resection, a significantly enhanced inhibition on tumor reoccurrence was demonstrated. Thus, the polypeptide hydrogel-based chemo-immunotherapy strategy has potential in anti-tumor therapy and the prevention of tumor reoccurrence.

An intra‐articular injectable phospholipids‐based gel for the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory and destructive arthropathy with a high deformity rate. Despite numerous studies and clinical trials, no curative treatment is available for large weight-bearing joints. Intra-articular (IA) injections could deliver high concentrations of drug to the afflicted joint and improve the drug efficacy while reducing systemic toxicity. However, free drugs are rapidly cleared from synovial fluid and do not significantly halt the progression of joint disease. Herein, a phospholipids-based controlled-release gel was prepared for sustained IA delivery of celastrol (CEL) and the therapeutic efficiency was evaluated in a rheumatoid arthritis rabbit model. The CEL-loaded gel (CEL-gel) contained up to 70% phospholipids yet was easy to inject. After injecting into the joint cavity, CEL-gel achieved sol to gel phase transition without special stimuli and gelling agent. In vitro release and in vivo pharmacokinetic studies evidenced the stable and sustained release action of CEL-gel. A single IA injection of CEL-gel could maintain therapeutic efficiency for about 25 d and showed much better anti-arthritic efficacy compared to repeated injections of free drug solution (CEL-sol). Furthermore, the IA injection of CEL-gel greatly reduced the systemic toxicity of CEL. With good biocompatibility and biodegradability, CEL-gel might be a promising IA drug delivery system.

Biodegradable concanavalin A functionalized polycaprolactone nanoparticle: A promising avenue for cancer therapy.

Receptor-based tumor-selective delivery of therapeutic efficacy and therapeutic index of cytotoxic drugs that exhibit dose-limiting toxicity is observed. Concanavalin A (Con A) was selected as the ligand for the proposed system, which was appended to the polycaprolactone nanoparticles (NPs) carrying the drug to be a very efficient approach for the treatment of cancer. Preparation of plain polycaprolactone nanoparticles was carried out employing the emulsion diffusion evaporation technique. Con A was conjugated using carbodiimide chemistry by coupling -COOH group on the surface of nanoparticles. The paclitaxel-loaded Con A-conjugated nanoparticles were further subjected to the characterization of various parameters, that is, surface morphology, particle size, and polydispersity index. In vitro drug release study of both the formulations (plain & conjugated) was done using a dialysis tube up to 48 h in phosphate buffer (pH 7.4). Studies done in xenograft models evidently propose a dose-dependent cytotoxicity response, that is, shrink in % cell growth with increase in the concentration of the drug. The fluorescence photomicrograph clearly revealed the access of the Con A-conjugated nanoparticles to the tumor. A noteworthy biodistribution difference of the paclitaxel from prepared systems was observed. At the same time, Con A-coupled nanoparticles increased the accumulation of paclitaxel in the tumor cells. Hence, the Con A-conjugated nanoparticles formulation as compared to uncoupled solid lipid nanoparticles formulation and free drug solution showed nearly two times higher uptake because of the lectin receptors on the surface of tumors. Hence, it was envisaged to design polymeric nanoparticles which would be administered intravenously for better therapeutic efficacy.