Impact of Propeptide Cleavage on the Stability and Activity of a Streptococcal Immunomodulatory C5a Peptidase for Biopharmaceutical Development.

Posttranslational modifications of proteins can impact their therapeutic efficacy, stability, and potential for pharmaceutical development. The Group AStreptococcus pyogenesC5a peptidase (ScpA) is a multi-domain protein composed of an N-terminal signal peptide, a catalytic domain (including propeptide), three fibronectin domains, and cell membrane-associated domains. It is one of several proteins produced by Group AS. pyogenesknown to cleave components of the human complement system. After signal peptide removal, ScpA undergoes autoproteolysis and cleaves its propeptide for full maturation. The exact location and mechanism of the propeptide cleavage, and the impact of this cleavage on stability and activity, are not clearly understood, and the exact primary sequence of the final enzyme is not known. A form of ScpA with no autoproteolysis fragments of propeptide present may be more desirable for pharmaceutical development from a regulatory and a biocompatibility in the body perspective. The current study describes an in-depth structural and functional characterization of propeptide truncated variants of ScpA expressed inEscherichia colicells. All three purified ScpA variants, ScpA, 79ΔPro, and 92ΔPro, starting with N32, D79, and A92 positions, respectively, showed similar activity against C5a, which suggests a propeptide-independent activity profile of ScpA. CE-SDS and MALDI top-down sequencing analyses highlight a time-dependent propeptide autoproteolysis of ScpA at 37 °C with a distinct end point at A92 and/or D93. In comparison, all three variants of ScpA exhibit similar stability, melting temperatures, and secondary structure orientation. In summary, this work not only highlights propeptide localization but also provides a strategy to recombinantly produce a final mature and active form of ScpA without any propeptide-related fragments.

Inflammatory Bowel Disease Infusion Therapy Adherence in a Rural Pediatric Population.

INTRODUCTION: Biologic therapy is often used in patients with inflammatory bowel disease (IBD), which includes Crohn's Disease (CD) and ulcerative colitis (UC). While biologic therapy improves outcomes, it is dependent on strict compliance for optimal benefit. Limited information is available to describe IBD infusion therapy compliance and adherence barriers in a rural, geographically dispersed pediatric population. METHODS: Parents/guardians and patients (aged 0-21 years) with a diagnosis of IBD and scheduled biologic therapy infusions were offered a survey consisting of a mix of multiple-choice and open-ended questions. Surveys were offered via in-person paper format or telephone. RESULTS: Of the 27 pediatric patients completing the survey, the mean age was 14 years old (SD 3.7 years) with 19 patients having CD and eight patients with UC. The results showed that more than half of the patients (59%) had to reschedule, miss, or delayed their infusion therapy at least once. Therapy compliance was maintained as patients were able to reschedule a new appointment within two weeks. The most common reasons for missing appointments were forgetfulness and school conflicts. Patients wanting to maintain health and avoid flare-ups were reported as key drivers for therapy. CONCLUSION: Pediatric patients in rural and geographically disperse areas continue to have long commutes and other barriers to IBD specialty care. Forgetfulness and school activities were reported as barriers to biological therapy adherence. Protective factors including knowledge of therapy health benefits, parental involvement, and staff support can help maintain high adherence rates in this population.

Inclusion Complex of Ibuprofen-ß-Cyclodextrin Incorporated in Gel for Mucosal Delivery: Optimization Using an Experimental Design.

ß-Cyclodextrin/ibuprofen inclusion complex was synthesized by freeze-drying method and characterized for phase solubility profiles, infrared spectra, thermal analysis, and X-ray powder diffractograms. The inclusion complex with HP-ß-CD, as confirmed by molecular dynamics simulations, enhanced the aqueous solubility of ibuprofen by almost 30-fold compared to ibuprofen alone. Different grades of Carbopol (Carbopol 934P/Carbopol 974P/Carbopol 980 NF/Carbopol Ultrez 10 NF) and cellulose derivatives (HPMC K100M/HPMC K15M/HPMC K4M/HPMC E15LV/HPC) were evaluated for mucoadhesive gels incorporating the inclusion complex. The central composite design generated by Design-Expert was employed to optimize the mucoadhesive gel using two independent variables (a varying combination of two gelling agents) on three dependent variables (drug content and in vitro drug release at 6 h and 12 h). Except for the methylcellulose-based gels, most of the gels (0.5%, 0.75%, and 1% alone or as a mixture thereof) exhibited an extended-release of ibuprofen, ranging from 40 to 74% over 24 h and followed the Korsmeyer-Peppas kinetics model. Using this test design, 0.95% Carbopol 934P and 0.55% HPC-L formulations were optimized to increase ibuprofen release, enhance mucoadhesion, and be non-irritating in ex vivo chorioallantoic membrane studies. The present study successfully developed a mucoadhesive gel containing the ibuprofen-ß-cyclodextrin inclusion complex with sustained release.

The development of a solid lipid nanoparticle (SLN)-based lacticin 3147 hydrogel for the treatment of wound infections.

Chronic wounds affect millions of people globally. This number is set to rise with the increasing incidence of antimicrobial-resistant bacterial infections, such as methicillin-resistant Staphylococcus aureus (MRSA), which impair the healing of chronic wounds. Lacticin 3147 is a two-peptide chain bacteriocin produced by Lactococcus lactis that is active against S. aureus including MRSA strains. Previously, poor physicochemical properties of the peptides were overcome by the encapsulation of lacticin 3147 into solid lipid nanoparticles. Here, a lacticin 3147 solid lipid nanoparticle gel is proposed as a topical treatment for S. aureus and MRSA wound infections. Initially, lacticin 3147's antimicrobial activity against S. aureus was determined before encapsulation into solid lipid nanoparticles. An optimised gel formulation with the desired physicochemical properties for topical application was developed, and the lacticin-loaded solid lipid nanoparticles and free lacticin 3147 aqueous solution were incorporated into separate gels. The release of lacticin 3147 from both the solid lipid nanoparticle and free lacticin gels was measured where the solid lipid nanoparticle gel exhibited increased activity for a longer period (11 days) compared to the free lacticin gel (9 days). Both gels displayed potent activity ex vivo against S. aureus-infected pig skin with significant bacterial eradication (> 75%) after 1 h. Thus, a long-acting potent lacticin 3147 solid lipid nanoparticle gel with the required physicochemical properties for topical delivery of lacticin 3147 to the skin for the potential treatment of S. aureus-infected chronic wounds was developed.

Development of amino acid-modified biodegradable lipid nanoparticles for siRNA delivery.

The use of siRNA therapeutics to treat cancer is a very promising approach. However, specific delivery of siRNAs to tumors remains a major challenge. The recent success of siRNA delivery to the liver has incentivized the development of biomaterials for siRNA delivery into tumors. Here, we report a new class of amino acid-modified lipids for siRNA delivery to cancer cells. Eight lipids were developed by headgroup modification with histidine and lysine. The lipids were screened in PC3-luciferase stable cells for gene silencing and cellular cytotoxicity study. The best lipid LHHK shows a pKa of 6.08, which is within the optimal pKa range of lipid nanoparticles (LNPs) for siRNA delivery. The LHHK LNP protects siRNA from serum degradation for up to 24 h and shows higher endosomal release and better cellular uptake compared to other lysine-modified lipids in PC3 cells. The LHHK LNP exhibits significant silencing activity of IKKα and IKBKE in prostate cancer and pancreatic cancer, respectively. Moreover, the LHHK LNP encapsulating IKBKE siRNA inhibits cell proliferation of pancreatic cancer cells and suppresses the tumor progression in a pancreatic cancer mouse model. STATEMENT OF SIGNIFICANCE: Lipid nanoparticle (LNP) is a promising platform for siRNA delivery. However, LNP is generally associated with high systemic toxicity. As a result, efficient and biodegradable lipids are highly needed for siRNA-based cancer therapy. Herein, we develop amino acid-modified biodegradable lipids. These lipids show very low cellular toxicity and high transfection efficiency. The best lipid LHHK shows a pKa of 6.08, which is within the optimal pKa range of LNPs for siRNA delivery. The LHHK LNP efficiently silences IKKα and IKBKE in prostate and pancreatic cancer, respectively. Moreover, the LHHK LNP encapsulating IKBKE siRNA inhibits cell proliferation and suppresses tumor growth of pancreatic cancer in vivo. These results suggest that amino acid-modified lipids possess a great potential for siRNA delivery in cancer therapy.

Discovery of Cyclic Peptide Inhibitors Targeting PD-L1 for Cancer Immunotherapy.

Blockade of the interaction between programmed cell death ligand-1 (PD-L1) and its receptor PD-1 has shown great success in cancer immunotherapy. Peptides possess unique characteristics that give them significant advantages as immune checkpoint inhibitors. However, unfavorable physicochemical properties and proteolytic stability profiles limit the translation of bioactive peptides as therapeutic agents. Studies have revealed that cyclization improves the biological activity and stability of linear peptides. In this study, we report the use of macrocyclization scanning for the discovery of cyclic anti-PD-L1 peptides with improved bioactivity. The cyclic peptides demonstrated up to a 34-fold improvement in the PD-1/PD-L1 blocking activity and significant in vivo anti-tumor activity. Our results demonstrate that macrocyclization scanning is an effective way to improve the serum stability and bioactivity of the anti-PD-L1 linear peptide. This strategy can be employed in the optimization of other bioactive peptides, particularly those for protein-protein interaction modulation.

Single versus double occupancy solid lipid nanoparticles for delivery of the dual-acting bacteriocin, lacticin 3147.

The bacteriocin lacticin 3147 (lacticin) has shown activity against clinically relevant and antimicrobial-resistant bacteria such as Listeria monocytogenes and Clostridioides difficile. It is composed of two peptides, Ltnα and Ltnß, which work together to form pores in the membrane of Gram-positive bacteria. Lacticin possesses poor aqueous solubility and is degraded by intestinal proteases. In a previous study, peptides encapsulated into solid lipid nanoparticles (SLNs) displayed activity in aqueous media and were protected from enzyme degradation but showed a low encapsulation efficiency (EE%) for Ltnα. In this study, however, lacticin was encapsulated into SLNs both individually (single occupancy, SLNα + SLNß) and together (double occupancy SLNαß) via a nanoprecipitation technique. This achieved SLNs of uniform size with an EE% above 87% for both peptides at loadings of 9 or 18 mg/g of lipid under single occupancy or double occupancy respectively. SLNαß dispersions displayed more potent activity at 3.13 and 1.56 µg/ml lacticin than SLNα + SLNß dispersions. Thus, the SLNαß dispersion was chosen for further analysis. SLNαß dispersions showed no cytotoxicity to endothelial cells. The SLN release media (fasted state simulated intestinal fluid; FaSSIF) retained activity at 1 h and 3 h indicating that lacticin may be sufficiently protected from proteases present in the duodenum. Finally, a reconstituted freeze-dried SLNαß dispersion was stable and achieved 99.99% bacterial killing at 3.125 µg/ml lacticin. Thus, an SLN based lacticin delivery system was developed, potentially enabling oral administration of the bacteriocin to the colon to treat local infections such as C. difficile.

An ion-paired moxifloxacin nanosuspension eye drop provides improved prevention and treatment of ocular infection.

There are numerous barriers to achieving effective intraocular drug administration, including the mucus layer protecting the ocular surface. For this reason, antibiotic eye drops must be used multiple times per day to prevent and treat ocular infections. Frequent eye drop use is inconvenient for patients, and lack of adherence to prescribed dosing regimens limits treatment efficacy and contributes to antibiotic resistance. Here, we describe an ion-pairing approach used to create an insoluble moxifloxacin-pamoate (MOX-PAM) complex for formulation into mucus-penetrating nanosuspension eye drops (MOX-PAM NS). The MOX-PAM NS provided a significant increase in ocular drug absorption, as measured by the area under the curve in cornea tissue and aqueous humor, compared to Vigamox in healthy rats. Prophylactic and treatment efficacy were evaluated in a rat model of ocular Staphylococcus aureus infection. A single drop of MOX-PAM NS was more effective than Vigamox, and completely prevented infection. Once a day dosing with MOX-PAM NS was similar, if not more effective, than three times a day dosing with Vigamox for treating S. aureus infection. The MOX-PAM NS provided increased intraocular antibiotic absorption and improved prevention and treatment of ocular keratitis, and the formulation approach is highly translational and clinically relevant.

Docusate-Based Ionic Liquids of Anthelmintic Benzimidazoles Show Improved Pharmaceutical Processability, Lipid Solubility, and in Vitro Activity against Cryptococcus neoformans.

As the existing therapeutic modalities for the treatment of cryptococcal meningitis (CM) have suboptimal efficacy, repurposing existing drugs for the treatment of CM is of great interest. The FDA-approved anthelmintic benzimidazoles, albendazole, mebendazole, and flubendazole, have demonstrated potent but variable in vitro activity against Cryptococcus neoformans, the predominant fungal species responsible for CM. We performed molecular docking studies to ascertain the interaction of albendazole, mebendazole, and flubendazole with a C. neoformans ß-tubulin structure, which revealed differential binding interactions and explained the different in vitro efficacies reported previously and observed in this investigation. Despite their promising in vitro efficacy, the repurposing of anthelmintic benzimidazoles for oral CM therapy is significantly hampered due to their high crystallinity, poor pharmaceutical processability, low and pH-dependent solubility, and drug precipitation upon entering the intestine, all of which result in low and variable oral bioavailability. Here, we demonstrate that the anthelmintic benzimidazoles can be transformed into partially amorphous low-melting ionic liquids (ILs) with a simple metathesis reaction using amphiphilic sodium docusate as a counterion. In vitro efficacy studies on a laboratory reference and a clinical isolate of C. neoformans showed 2- to 4-fold lower IC90 values for docusate-based ILs compared to the pure anthelmintic benzimidazoles. Furthermore, using a C. neoformans strain with green fluorescent protein (GFP)-tagged ß-tubulin and albendazole and its docusate IL as model candidates, we showed that the benzimidazoles and their ILs reduce the viability of C. neoformans by interfering with its microtubule assembly. Unlike pure anthelmintic benzimidazoles, the docusate-based ILs showed excellent solubility in organic solvents and >30-fold higher solubility in bioavailability-enhancing lipid vehicles. Finally, the docusate ILs were successfully incorporated into SoluPlus, a self-assembling biodegradable polymer, which upon dilution with water formed polymeric micelles with a size of <100 nm. Thus, the development of docusate-based ILs represents an effective approach to improve the physicochemical properties and potency of anthelmintic benzimidazoles to facilitate their repurposing and preclinical development for CM therapy.

Microemulsion-based gel for the transdermal delivery of rasagiline mesylate: In vitro and in vivo assessment for Parkinson's therapy.

Rasagiline mesylate (RSM) is a selective and irreversible monoamine oxidase B inhibitor used for the treatment of Parkinson's disease (PD). However, its unfavorable biopharmaceutical properties, such as extensive degradation in the gastrointestinal tract and first-pass metabolism are responsible for its low oral bioavailability and suboptimal therapeutic efficacy. Here, we report the feasibility of delivering RSM via the transdermal route using RSM containing microemulsion-based gel (RSM-MEG) to achieve effective management of PD. Our in vitro skin permeation studies of RSM-MEG showed significantly higher (at least ~1.5-fold) permeation across rat skin compared to the conventional RSM hydrogel. Our skin irritation studies in rabbits showed that RSM-MEG is safe for transdermal application. Finally, using the rat model of rotenone-induced Parkinsonism, we demonstrated that the topical application of RSM-MEG was equally effective in reversing PD symptoms when compared to oral RSM therapy. Thus, our study confirmed the feasibility and potential of transdermal delivery of RSM via simple topical application of RSM-MEG, and this approach could be an alternative therapeutic intervention for the treatment of Parkinson's disease.

The Importance of Apparent pKa in the Development of Nanoparticles Encapsulating siRNA and mRNA.

Polymer and lipid nanoparticles have been extensively used as carriers to address the biological barriers encountered in siRNA and mRNA delivery. We summarize the crucial role of nanoparticle charge and ionizability in complexing RNAs, binding to biological components, escaping from the endosome, and releasing RNAs into the cytoplasm. We highlight the significant impact of the apparent pKa of nanoparticles on their efficacy and toxicity, and the importance of optimizing pKa in the development of lead formulations for RNAs. We also discuss the feasibility of fine-tuning the pKa in nanoparticles and the applications of this approach in the optimization of delivery systems for RNAs.

Pharmaceutical design of a delivery system for the bacteriocin lacticin 3147.

Lacticin 3147 is a dual-acting two-peptide bacteriocin which is generally active against Gram-positive bacteria, including Listeria monocytogenes and antimicrobial-resistant bacteria such as Closteroides difficile in the colon. L. monocytogenes infections can cause life-long effects in the elderly and vulnerable and can cause severe complications in pregnant women. C. difficile causes one of the most common healthcare-associated infections and can be fatal in vulnerable groups such as the elderly. Although lacticin 3147 is degraded by intestinal proteases and has poor aqueous solubility, encapsulation of the bacteriocin could enable its use as an antimicrobial for treating these bacterial infections locally in the gastrointestinal tract. Lacticin 3147 displayed activity in aqueous solutions at a range of pH values and in gastric and intestinal fluids. Exposure to trypsin and α-chymotrypsin resulted in complete inactivation, implying that lacticin 3147 should be protected from these enzymes to achieve successful local delivery to the gastrointestinal tract. The amount of lacticin 3147 dissolved, i.e. its solution concentration, in water or buffered solutions at pH 1.6 and 7.4 was low and varied with time but increased and was stabilized in gastrointestinal fluids by the phospholipid and bile salt components present. Thus, the feasibility of a solid lipid nanoparticle (SLN) delivery system for local administration of lacticin 3147 was investigated. Bacteriocin activity was observed after encapsulation and release from a lipid matrix. Moreover, activity was seen after exposure to degrading enzymes. Further optimization of SLN delivery systems could enable the successful pharmaceutical development of active lacticin 3147 as an alternative to traditional antibiotics.

Synthesis and Characterization of Lipophilic Salts of Metformin to Improve Its Repurposing for Cancer Therapy.

Epidemiological evidence has accentuated the repurposing of metformin hydrochloride for cancer treatment. However, the extreme hydrophilicity and poor permeability of metformin hydrochloride are responsible for its poor anticancer activity in vitro and in vivo. Here, we report the synthesis and characterization of several lipophilic metformin salts containing bulky anionic permeation enhancers such as caprate, laurate, oleate, cholate, and docusate as counterions. Of various counterions tested, only docusate was able to significantly improve the lipophilicity and lipid solubility of metformin. To evaluate the impact of the association of anionic permeation enhancers with metformin, we checked the in vitro anticancer activity of various lipophilic salts of metformin using drug-sensitive (MYCN-2) and drug-resistant (SK-N-Be2c) neuroblastoma cells as model cancer cells. Metformin hydrochloride showed a very low potency (IC50 ≈ >100 mM) against MYCN-2 and SK-N-Be2c cells. Anionic permeation enhancers showed a considerably higher activity (IC50 ≈ 125 µM to 1.6 mM) against MYCN-2 and SK-N-Be2c cells than metformin. The association of metformin with most of the bulky anionic agents negatively impacted the anticancer activity against MYCN-2 and SK-N-Be2c cells. However, metformin docusate showed 700- to 4300-fold improvement in anticancer potency compared to metformin hydrochloride and four- to five-fold higher in vitro anticancer activity compared to sodium docusate, indicating a synergistic association between metformin and docusate. A similar trend was observed when we tested the in vitro activity of metformin docusate, sodium docusate, and metformin hydrochloride against hepatocellular carcinoma (HepG2) and triple-negative breast cancer (MDA-MB-231) cells.

Pharmaceutically Acceptable Carboxylic Acid-Terminated Polymers Show Activity and Selectivity against HSV-1 and HSV-2 and Synergy with Antiviral Drugs.

Polyanionic macromolecules including carboxylate-terminated polymers (polycarboxylates) are capable of inhibiting sexually transmitted viruses such as human immunodeficiency virus (HIV) and herpes simplex virus (HSV). Cellulose acetate phthalate (CAP), a pharmaceutically acceptable pH-sensitive polycarboxylate polymer, showed promising prophylactic activity against HIV and HSV, but the instability of CAP in an aqueous environment prevented its clinical development. Interestingly, several pharmaceutically acceptable polycarboxylates have features similar to CAP with an aqueous stability significantly higher than that of CAP. However, their activity against sexually transmitted viruses remains unexplored. Here, we evaluate the activity of various polycarboxylates such as polyvinyl acetate phthalate (PVAP), various grades of hydroxypropyl methylcellulose phthalate (HPMCP-50, HPMCP-55, and HPMCP-55S), and various grades of methacrylic acid copolymers (Eudragit L100-55, Eudragit L100, Eudragit S100, and Kollicoat MAE 100P) against HSV. We, for the first time, demonstrate that PVAP, HPMCP-55S, and Eudragit S100 have activity and selectivity against HSV-1 and HSV-2. Further, we report that polycarboxylates can be easily transformed into nanoparticles (NPs) and in the nanoparticulate form, they show similar or enhanced activity against HSV. Finally, using PVAP NPs, as a model, we demonstrate using in vitro HSV therapy studies that polycarboxylate NPs are capable of synergizing with antiviral drugs such as acyclovir (ACV), tenofovir, and tenofovir disoproxil fumarate. Thus, pharmaceutically acceptable carboxylic acid-terminated polymers and their NPs have the potential to be developed into topical formulations for the prevention and treatment of HSV infection.

Co-delivery of IKBKE siRNA and cabazitaxel by hybrid nanocomplex inhibits invasiveness and growth of triple-negative breast cancer.

IKBKE is an oncogene in triple-negative breast cancer (TNBC), and we demonstrate that IKBKE small interfering RNA (siRNA) inhibits the proliferation, migration, and invasion of TNBC cells. Despite the recent success of siRNA therapeutics targeting to the liver, there still remains a great challenge to deliver siRNAs to solid tumors. Here, we report a hybrid nanocomplex to co-deliver the IKBKE siRNA and cabazitaxel to TNBC to achieve an optimal antitumor effect. The nanocomplex is modified with hyaluronic acid to target CD44 on TNBC cells. The nanocomplex shows higher cellular uptake and better tumor penetration of the encapsulated cargos. The nanocomplex also exhibits high tumor accumulation and antitumor activity in an orthotopic TNBC mouse model. Encapsulation of cabazitaxel in the nanocomplex enhances the activity of the IKBKE siRNA. The hybrid nanocomplex provides a novel and versatile platform for combination therapies using siRNAs and chemotherapy.

Celiac Disease in a 16-Month-Old Child Presenting as Motor Regression.

Neurodevelopmental symptoms were previously believed to be a complication of celiac disease (CD) and rarely seen as presenting symptoms. One case has been reported so far where motor regression was the presenting symptom. We present a 16-month-old girl with postprandial vomiting and regression of motor skills. Examination revealed abdominal distension, hypotonia, and decreased motor movements in lower extremities. Celiac serology showed elevated tissue transglutaminase (tTG) immunoglobulin A (IgA) levels. Esophagogastroduodenoscopy with biopsies confirmed CD. Gluten-free diet led to the improvement of neurological and gastrointestinal complaints. We recommend keeping CD as one of the differentials in children with neurodevelopmental symptoms.

Multi-Layered Nanomicelles as Self-Assembled Nanocarrier Systems for Ocular Peptide Delivery.

Despite the great potential of peptides as therapeutics, there is an unmet challenge in sustaining delivery of sufficient amounts in their native forms. This manuscript describes a novel nanocarrier capable of delivering functional small peptides in its native form. Self-assembling multi-layered nanomicelles composed of two polymers, polyoxyethylene hydrogenated castor oil 40 (HCO-40) and octoxynol 40 (OC-40), were designed to combine hydrophilic interaction and solvent-induced encapsulation of peptides and proteins. The polymers are employed to encapsulate peptide or protein in the core of the organo-nanomicelles which are further encapsulated with another layer of the same polymers to form an aqueous stable nanomicellar solution. The size of the multi-layered nanomicelles ranges from ~ 16 to 20 nm with zeta potential close to neutral (~ - 2.44 to 0.39 mV). In vitro release studies revealed that octreotide-loaded multi-layered nanomicelles released octreotide at much slower rate in simulated tear fluid (STF) (~ 27 days) compared to PBST (~ 11 days) in its native form. MTT assay demonstrated negligible toxicity of the multi-layered nanomicelles at lower concentrations in human retinal pigment epithelial (HRPE, D407), human conjunctival epithelial (CCL 20.2), and rhesus choroid-retinal endothelial (RF/6A) cells. This work demonstrates an efficient small peptide delivery platform with significant advantages over existing approaches, as it does not require modification of the peptide, is biodegradable, and has a small size and high loading capacity.

Solid lipid nanoparticles of amphotericin B (AmbiOnp): in vitro and in vivo assessment towards safe and effective oral treatment module.

Amphotericin B, a gold standard broad spectrum antibiotic used in treatment of systemic fungal infections and visceral leishmaniasis, though is effective parenterally offers severe nephrotoxicity whereas the oral delivery is reported to give very meager oral bioavailability. Thus, to alleviate the toxicity and to improve oral bioavailability, an effective oral delivery approach in the form of solid lipid nanoparticles of amphotericin B (AmbiOnp) was reported earlier by our group. In this investigation, we report the predominant formation of nontoxic superaggregated form of amphotericin B, resulting from the probe sonication-assisted nanoprecipitation technique. The developed formulation was further confirmed to retain this nontoxic form and was found to be stable over the varied gastrointestinal conditions. Further, in vitro antifungal activity of AmbiOnp against Candida albicans showed minimum inhibitory concentration value of 7.812 µg/mL attributed to controlled release of drug from nanoparticulate matrix. In vivo pharmacokinetic studies revealed a relative bioavailability of AmbiOnp to be 1.05-fold with a Cmax of 1109.31 ± 104.79 ng/mL at the end of 24 h which was comparable to Cmax of 1417.49 ± 85.52 ng/mL achieved with that of marketed formulation (Fungizone®) given intravenously establishing efficacy of AmbiOnp. In vivo biodistribution studies indicated very low levels of Amphotericin B in kidneys when given as AmbiOnp as compared to that of marketed formulation proving its safety and was further corroborated by renal toxicity studies. Further, the formulations were found to be stable under refrigeration condition over a period of 3 months.

The influence of salinity and copper exposure on copper accumulation and physiological impairment in the sea anemone, Exaiptasia pallida.

Copper is a common pollutant in many aquatic environments, particularly those surrounding densely populated areas with substantial anthropogenic inputs. These same areas may also experience changes in salinity due to freshwater discharge and tidal influence. Biota that inhabit near-shore coastal environments may be susceptible to both stressors. Although copper is a noted concern in marine environments, effects of copper and varying salinity on symbiotic cnidarians are only scarcely studied. The sea anemone, Exaiptasia pallida, was used to investigate effects of copper on physiological impairment (i.e. activities of anti-oxidant enzymes) at two different salinities (20 and 25ppt). E. pallida was exposed to a control and three elevated copper concentrations for up to 21d, and copper accumulation and activity of the enzymes: catalase, glutathione reductase, glutathione peroxidase, and carbonic anhydrase were measured in the anemones. Photosynthetic parameters in E. pallida's symbiotic dinoflagellate algae were also quantified. Over the course of the exposure, E. pallida accumulated copper in a concentration-dependent manner. Higher tissue copper concentrations were observed in anemones exposed to the lower salinity water (20ppt), and physiological impairment was observed as a consequence of both increased copper exposure and decreased salinity; however, changes in salinity caused a greater response than copper exposure, at the levels tested. In general, antioxidant enzyme activity increased as a consequence of decreased salinity and/or increased copper exposure. These results clearly demonstrated the influence of two local stressors, at environmentally realistic concentrations, on a sensitive cnidarian, and highlight the importance of characterizing combined exposure scenarios.