Microemulsion-based delivery of triamcinolone acetonide to posterior segment of eye using chitosan and butter oil as permeation enhancer: an in vitro and in vivo investigation

Studies on cationic ocular emulsions containing bipartitioned oil droplets to codeliver cyclosporin A and etodolac

Background: To prepare ocular emulsions containing bipartitioned oil droplets to entrap cyclosporin A (0.05% w/w) and etodolac (0.2% w/w) by using castor, olive and silicon oils. Methods: The physicochemical characterizations of prepared emulsions were performed. The drug's biodistribution profiles and pharmacokinetic parameters from emulsions were checked using the ultraperformance liquid chromatography-tandem mass spectrometry method in the ocular tissues of the healthy rabbit eye model. Results: The emulsions displayed 365.13 ± 7.21 nm size and 26.45 ± 2.09 mV zeta potential. The ferrying of two drugs after releasing from emulsions occurred across corneal/conjunctival tissues to enter the vitreous and sclera following a single drop administration into the rabbit's eyes. Conclusion: The dual drug-loaded emulsions were more likely to produce synergistic anti-inflammatory activity for managing moderate-to-severe dry eye disease.

Glycol Chitosan-Poly(lactic acid) Conjugate Nanoparticles Encapsulating Ciprofloxacin: A Mucoadhesive, Antiquorum-Sensing, and Biofilm-Disrupting Treatment Modality for Bacterial Keratitis

Bacterial keratitis (BK) causes visual morbidity/blindness if not treated effectively. Here, ciprofloxacin (CIP)-loaded nanoparticles (NPs) using glycol chitosan (GC) and poly(lactic acid) (PLA) conjugate at three different ratios (CIP@GC(PLA) NPs (1:1,5,15)) were fabricated. CIP@GC(PLA) NPs (1:1) were more effective than other tested ratios, indicating the importance of optimal hydrophobic/hydrophilic balance for corneal penetration and preventing bacterial invasion. The CIP@GC(PLA) (NPs) (1:1) realized the highest association with human corneal epithelial cells, which were nonirritant to the hen's egg-chorioallantoic membrane test (HET-CAM test) and demonstrated significant antibacterial response in the in vitro minimum inhibitory, bactericidal, live-dead cells, zone of inhibition, and biofilm inhibition assays against the keratitis-inducing pathogen Pseudomonas aeruginosa. The antiquorum sensing activity of GC has been explored for the first time. The NPs disrupted the bacterial quorum sensing by inhibiting the production of virulence factors, including acyl homoserine lactones, pyocyanin, and motility, and caused significant downregulation of quorum sensing associated genes. In the in vivo studies, CIP@GC(PLA) NPs (1:1) displayed ocular retention in vivo (∼6 h) and decreased the opacity and the bacterial load effectively. Overall, the CIP@GC(PLA) NP (1:1) is a biofilm-disrupting antiquorum sensing treatment regimen with clinical translation potential in BK.

Ocular Drug Delivery: a Comprehensive Review

The human eye is a sophisticated organ with distinctive anatomy and physiology that hinders the passage of drugs into targeted ophthalmic sites. Effective topical administration is an interest of scientists for many decades. Their difficult mission is to prolong drug residence time and guarantee an appropriate ocular permeation. Several ocular obstacles oppose effective drug delivery such as precorneal, corneal, and blood-corneal barriers. Routes for ocular delivery include topical, intravitreal, intraocular, juxtascleral, subconjunctival, intracameral, and retrobulbar. More than 95% of marketed products exists in liquid state. However, other products could be in semi-solid (ointments and gels), solid state (powder, insert and lens), or mixed (in situ gel). Nowadays, attractiveness to nanotechnology-based carries is resulted from their capabilities to entrap both hydrophilic and lipophilic drugs, enhance ocular permeability, sustain residence time, improve drug stability, and augment bioavailability. Different in vitro, ex vivo, and in vivo characterization approaches help to predict the outcomes of the constructed nanocarriers. This review aims to clarify anatomy of the eye, various ocular diseases, and obstacles to ocular delivery. Moreover, it studies the advantages and drawbacks of different ocular routes of administration and dosage forms. This review also discusses different nanostructured platforms and their characterization approaches. Strategies to enhance ocular bioavailability are also explained. Finally, recent advances in ocular delivery are described.

Pterostilbene-Loaded Soluplus/Poloxamer 188 Mixed Micelles for Protection against Acetaminophen-Induced Acute Liver Injury

Excessive acetaminophen (APAP) induces excess reactive oxygen species (ROS), leading to liver damage. Pterostilbene (PTE) has excellent antioxidant and anti-inflammatory activities, but poor solubility limits its biological activity. In this study, we prepared PTE-loaded Soluplus/poloxamer 188 mixed micelles (PTE-MMs), and the protective mechanism against APAP-induced liver injury was investigated. In vitro results showed that PTE-MMs protected H₂O₂-induced HepG2 cell proliferation inhibition, ROS accumulation, and mitochondrial membrane potential destruction. Immunofluorescence results indicated that PTE-MMs significantly inhibited H₂O₂-induced DNA damage and cGAS-STING pathway activation. For in vivo protection studies, PTE-MMs (25 and 50 mg/kg) were administered orally for 5 days, followed by APAP (300 mg/kg). The results showed that APAP significantly induced injury in liver histopathology as well as an increase in serum aspartate aminotransferase and alanine aminotransferase levels. Moreover, the above characteristics of APAP-induced acute liver injury were inhibited by PTE-MMs. In addition, APAP-induced changes in the activities of antioxidant enzymes such as SOD and GSH in liver tissue were also inhibited by PTE-MMs. Immunohistochemical results showed that PTE-MMs inhibited APAP-induced DNA damage and cGAS-STING pathway activation in liver tissues. For in vivo therapeutic effect study, mice were first given APAP (300 mg/kg), followed by oral administration of PTE-MMs (50 mg/kg) for 3 days. The results showed that PTE-MMs exhibited promising therapeutic effects on APAP-induced acute liver injury. In conclusion, our study shows that the Soluplus/poloxamer 188 MM system has the potential to enhance the biological activity of PTE in the protection and therapeutic of liver injury.

Studies on pomegranate seed oil enriched galantamine hydrobromide microemulsion: formulation, in vitro antioxidant and neuroprotective potential

Pomegranate seed oil with its high levels of phenolic compounds is known to exhibit neuroprotective effects. Delivering hydrophilic drugs to the brain is challenging since blood-brain barrier allows only a few lipophilic molecules into the brain, thus posing an additional barrier for drug delivery to the brain in conditions like Alzheimer's. The present study focuses on the preparation of the stable galantamine hydrobromide (GHBr) microemulsion (ME) using pomegranate seed oil (PSO) as an adjuvant. The developed ME was characterized for various physicochemical properties, cytotoxicity, and protective role against Amyloid Beta (1-42) oligomer-induced toxicity in IMR 32 cell line. GHBr and PSO ratio was optimized based on an in-vitro diffusion study and compatibility study using DSC and FTIR. The ME was prepared by the water titration method and optimized using the one variable at a time (OVAT) strategy. Globule size and PDI of GHBr PSO ME were found to be 200.36 ± 0.01 nm, and 0.219 ± 0.011 nm respectively. GHBr PSO ME showed significantly better results in terms of cell line toxicity, antioxidant activity and protective effect against Aβ induced cell death. The results obtained showed the potential of using PSO as an effective synergistic agent along with the anti-Alzheimer's drug for the treatment of disease.

Besifloxacin-loaded ocular nanoemulsions: design, formulation and efficacy evaluation

The purpose of this study was to develop and evaluate nanoemulsions (NEs) containing besifloxacin for ocular drug delivery. Pseudo ternary phase diagrams were constructed using Triacetin (oil), Cremophor® RH 40 (surfactant), and Transcutol®P (co-surfactant) to identify NE regions. Six formulations were developed by low-energy emulsification method and then evaluated for size, refractive index, pH, osmolality, viscosity, and drug release. After accelerated physical stability and bovine conrneal permeation studies, NE2 was chosen as optimized formulation forantimicrobial efficacy, and hen's egg test-chorioallantoic membrane (HET-CAM) tests. The particle size of optimum NE was 14 nm with a narrow size distribution. Moreover, other physicochemical characterizations were in the acceptable range for ocular administration. Besifloxacin-loaded NEs demonstrated sustained release pattern and 1.7-fold higher permeation compared with the control suspension in the ex vivo transcorneal permeation study. HET-CAM test indicated no irritation, and HL% revealed no damage to the tissue, so the optimum NE is well tolerated by the eye. In vitro antimicrobial evaluation, showed comparative efficacy of lower drug-loaded NE (0.2%) versus 0.6% besifloxacin suspension (equal concentration to commercial besifloxacin eye drop). In conclusion, besifloxacin-loaded NEs could be considered as a suitable alternative to the marketed suspension for treating bacterial eyeinfections.

Lipid Nanoparticles for the Posterior Eye Segment

This review highlights the application of lipid nanoparticles (Solid Lipid Nanoparticles, Nanostructured Lipid Carriers, or Lipid Drug Conjugates) as effective drug carriers for pathologies affecting the posterior ocular segment. Eye anatomy and the most relevant diseases affecting the posterior segment will be summarized. Moreover, preparation methods and different types and subtypes of lipid nanoparticles will also be reviewed. Lipid nanoparticles used as carriers to deliver drugs to the posterior eye segment as well as their administration routes, pharmaceutical forms and ocular distribution will be discussed emphasizing the different targeting strategies most recently employed for ocular drug delivery.

Recent advances in ophthalmic preparations: Ocular barriers, dosage forms and routes of administration

The human eye is a complex organ with unique anatomy and physiology that restricts the delivery of drugs to target ocular tissues/sites. Recent advances in the field of pharmacy, biotechnology and material science have led to development of novel ophthalmic dosage forms which can provide sustained drug delivery, reduce dosing frequency and improve the ocular bioavailability of drugs. This review highlights the different anatomical and physiological factors which affect ocular bioavailability of drugs and explores advancements from 2016 to 2020 in various ophthalmic preparations. Different routes of drug administration such as topical, intravitreal, intraocular, juxtascleral, subconjunctival, intracameral and retrobulbar are discussed with their advances and limitations.

Posterior Segment Ophthalmic Drug Delivery: Role of Muco-Adhesion with a Special Focus on Chitosan

Posterior segment eye diseases (PSEDs) including age macular degeneration (AMD) and diabetic retinopathy (DR) are amongst the major causes of irreversible blindness worldwide. Due to the numerous barriers encountered, highly invasive intravitreal (IVT) injections represent the primary route to deliver drugs to the posterior eye tissues. Thus, the potential of a more patient friendly topical route has been widely investigated. Mucoadhesive formulations can decrease precorneal clearance while prolonging precorneal residence. Thus, they are expected to enhance the chances of adherence to corneal and conjunctival surfaces and as such, enable increased delivery to the posterior eye segment. Among the mucoadhesive polymers available, chitosan is the most widely explored due to its outstanding mucoadhesive characteristics. In this review, the major PSEDs, their treatments, barriers to topical delivery, and routes of topical drug absorption to the posterior eye are presented. To enable the successful design of mucoadhesive ophthalmic drug delivery systems (DDSs), an overview of mucoadhesion, its theory, characterization, and considerations for ocular mucoadhesion is given. Furthermore, chitosan-based DDs that have been explored to promote topical drug delivery to the posterior eye segment are reviewed. Finally, challenges of successful preclinical to clinical translation of these DDSs for posterior eye drug delivery are discussed.

Comparative evaluation of fish oil and butter oil in modulating delivery of galantamine hydrobromide to brain via intranasal route: pharmacokinetic and oxidative stress studies

The present study investigates the role of fish oil (FO)- and butter oil (BO)-enriched microemulsion-based system of galantamine hydrobromide (GH), an anti-Alzheimer drug, for its potential role in brain permeation enhancement and neuroprotection against oxidative stress. Microemulsion (ME)-based system of GH was prepared using water phase titration. The prepared ME was characterized by several physicochemical parameters like particle size, polydispersity index, and ex vivo drug permeation. Cell-based oxidative stress assays and pharmacokinetic studies were performed using C6 glial cell lines, and Sprague Dawley rats, respectively. The optimized ME comprised 5.3% v/v of Capmul MCM EP (as oil),15.8% v/v of Tween-80 (as surfactant), 5.3% v/v of Transcutol P (as co-surfactant), and 73.6% v/v of water (as aqueous phase). The addition of FO and BO resulted in a slight increase in the droplet size and decrease in transparency of ME. Cell-based anti-oxidative stress assays (glutathione assay, nitrite assay, and lipid peroxidation assay) showed the efficacy of formulation in the order of ME, BO ME, and FO ME, respectively. A similar trend was also observed in in vivo animal studies, wherein GH FO ME showed a comparatively higher percentage of drug reaching the brain when administered by intranasal route than by IV route. The study concluded the potential benefits of co-administering FO- and BO-enriched microemulsion is not only enhancing the permeation of drugs across BBB but also improving efficacy against lipopolysaccharide-induced oxidative stress. Graphical abstract.

Studying the ophthalmic toxicity potential of developed ketoconazole loaded nanoemulsion in situ gel formulation for ophthalmic administration

Ocular fungal infections are one of the essential reasons for vision loss, especially in developing countries for tropical regions. Ketoconazole (KZ), a broad-spectrum antifungal drug, is a lipophilic compound and practically insoluble in water. Since topical ophthalmic drug delivery confronts low bioavailability, an in situ gel formulation is designed to improve the residence time and consequently the bioavailability. Safety of the developed formulation as a carrier for ophthalmic drug delivery was measured using three different methods: MTT assay for measuring cell viability in which the human retinal pigmentation epithelial cells (RPE) were used, HET-CAM as a borderline method between in vivo and in vitro techniques for investigating the irritation potential of the chosen formulation which was done by adding formulation directly on the CAM surface and visually monitoring the vessels in terms of irritation reactions, and finally the modified Draize test for evaluating tolerability of the selected formulation on eyes. According to our results from the MTT test, cell viability for KZ-NE in situ gel formulation at 0.1% concentration was acceptable. The results obtained from the HET-CAM investigation didn't show any sign of vessel injury on the CAM surface for prepared formulation. Additionally, during 24 hours, the developed formulation was tolerable by rabbit eyes. Regarding our results, KZ-NE in situ gel formulation was non-irritant and non-toxic and can be well-tolerated and presented as an applicable vehicle for ophthalmic delivery of the anti-fungal drug.

Engineered nanoplex mediated targeted miRNA delivery to rescue dying podocytes in diabetic nephropathy

MicroRNAs (miRNA) is vital for gene expression regulation and normal kidney function. Mainly, miRNA-30a is responsible for the homeostasis of podocytes. In the diabetic nephropathic condition, miRNA-30a is directly and primarily suppressed by hyperglycemic kidney induced Notch signaling pathway leads to podocyte damage and apoptosis. Thus, transferring the exogenous miRNA-30a to podocytes might improve albuminuria as well as podocytes injury. The deprived stability, poor targetability, and low specificity in vivo are critical limitations to attain this objective. This investigation reports the specific and efficient delivery of miRNA-30a mimic via cyclo(RGDfC)-gated polymeric-nanoplexes with dendrimer templates to alleviate podocyte conditions. The nanoplexes able to protect RNase enzyme and to exhibit greater cellular uptake viaαvβ3 receptor selective binding in HG treated podocytes. The nanoplexes up-regulated the expression level of miRNA-30a and repress the elevated Notch-1 signaling in HG exposed podocytes. The critical results of in vivo experimentation attribute marked suppression of Notch-1 in streptozotocin (STZ) induced diabetic C57BL/6 mice and reduced glomerular expansion and fibrosis in the glomerular area. Developed nanoplexes represents an efficient platform for the targeted delivery of exogenous miRNA to podocytes. The approach developed herein could be extrapolated to other gene therapeutics and other kidney-related diseases.

Development of Triamcinolone Acetonide-Loaded Microemulsion as a Prospective Ophthalmic Delivery System for Treatment of Uveitis: In Vitro and In Vivo Evaluation

Treatment of uveitis (i.e., inflammation of the uvea) is challenging due to lack of convenient ophthalmic dosage forms. This work is aimed to determine the efficiency of triamcinolone acetonide (TA)-loaded microemulsion as an ophthalmic delivery system for the treatment of uveitis. Water titration method was used to construct different pseudo-ternary phase diagrams. Twelve microemulsion formulations were prepared using oleic acid, Cremophor EL, and propylene glycol. Among all tested formulations, Formulation F3, composed of oil: surfactant-co-surfactant (1:1): water (15:35:50% w/w, respectively), was found to be stable and showed acceptable pH, viscosity, conductivity, droplet size (211 ± 1.4 nm), and zeta potential (-25 ± 1.7 mV) and almost complete in vitro drug release within 24 h. The in vivo performance of the optimized formulation was evaluated in experimentally uveitis-induced rabbit model and compared with a commercial TA suspension (i.e., Kenacort®-A) either topically or by subconjunctival injection. Ocular inflammation was evaluated by clinical examination, white blood cell count, protein content measurement, and histopathological examination. The developed TA-loaded microemulsion showed superior therapeutic efficiency in the treatment of uveitis with high patient compliance compared to commercial suspension. Hence, it could be considered as a potential ocular treatment option in controlling of uveitis.

Safety and Tolerability of Topical Ophthalmic Triamcinolone Acetonide-Loaded Liposomes Formulation and Evaluation of Its Biologic Activity in Patients with Diabetic Macular Edema

Intravitreal injections (IVTs) of corticosteroids as triamcinolone acetonide (TA) are frequently used for the treatment of many vitreous and retinal disorders. However, IVTs are related to severe ocular complications. Lately, a topical ophthalmic TA-loaded liposomes formulation (TALF) was designed to transport TA into the posterior segment of the eye when instilled on the ocular surface. To evaluate the safety, tolerability, and biological activity of TALF, an animal study and a phase I clinical assay were performed. Moreover, four patients with diabetic macular edema (DME) were treated with TALF in order to explore the biological activity of the formulation. No inflammation, lens opacity, swelling, or increase in intraocular pressure were recorded after the instillation of TALF in any of the animal or clinical studies. Mainly, mild and transient adverse events such as dry eye and burning were reported. TALF significantly improves visual acuity and diminishes central foveal thickness in patients with DME. The current data demonstrate the safety, tolerability, and biological activity of TALF. It seems that TALF can be used topically to treat vitreous and retinal diseases that respond to TA such as DME, avoiding the use of corticosteroid IVTs and their associated hazards.

Cyclo-RGD Truncated Polymeric Nanoconstruct with Dendrimeric Templates for Targeted HDAC4 Gene Silencing in a Diabetic Nephropathy Mouse Model

Diabetic nephropathy (DN), a chronic progressive kidney disease, is a significant complication of diabetes mellitus. Dysregulation of the histone deacetylases (HDACs) gene has been implicated in the pathogenesis of DN. Hence, the HDAC-inhibitors have emerged as a critical class of therapeutic agents in DN; however, the currently available HDAC4-inhibitors are mostly nonselective in nature as well as inhibit multiple HDACs. RNA interference of HDAC4 (HDAC4 siRNA) has shown immense promise, but the clinical translation has been impeded due to lack of a targeted, specific, and in vivo applicable delivery modality. In the present investigation, we examined Cyclo(RGDfC) (cRGD) truncated polymeric nanoplex with dendrimeric templates for targeted HDAC4 Gene Silencing. The developed nanoplex exhibited enhanced encapsulation of siRNA and offered superior protection against serum RNase nucleases degradation. The nanoplex was tested on podocytes (in vitro), wherein it showed selective binding to the αvβ3 integrin receptor, active cellular uptake, and significant in vitro gene silencing. The in vivo experiments showed remarkable suppression of the HDAC4 and inhibition in the progression of renal fibrosis in the Streptozotocin (STZ) induced DN C57BL/6 mice model. Histopathological and toxicological studies revealed nonsignificant abnormality/toxicity with the nanoplex. Conclusively, nanoplex was found as a promising tactic for targeted therapy of podocytes and could be extended for other kidney-related ailments.

Effect of antiseptic gels in the microbiologic colonization of the suture threads after oral surgery

Three different bioadhesive gels were evaluated in a double-blind randomized clinical trial in which microbial growth in the suture thread was assessed following post-surgical application of the aforementioned gels. Also assessed in this trial were, the intensity of post-surgical pain as well as the degree of healing of the patients’ surgical wounds. A total of 21 patients (with 42 wisdom teeth) participated in this trial. Chlorhexidine gel, chlorhexidine-chitosan gel, and hyaluronic acid gel were evaluated, with a neutral water-based gel serving as the control agent. The aerobic and facultative anaerobic bacterial recovery on blood agar was lower in the placebo group than in the experimental groups. The most significant difference (p = 0.04) was observed in the chlorhexidine-chitosan group. in which the growth of Blood Agar and Mitis Salivarius Agar was significantly higher than in the placebo group. The intensity of post-surgical pain was very similar among all the groups. Significantly better healing rates were observed in the patients treated with chlorhexidine-chitosan gel when compared with those who used the placebo gel (p = 0.03), and in particular when compared with those patients who used hyaluronic acid gel (p = 0.01). Through our microbiological analyses, we were able to conclude that none of the bioadhesive gels tested resulted in beneficial reductions in the bacterial/fungal populations. However, the healing rates of patients who were treated with chlorhexidine-chitosan were better than those of the patients who used either the placebo gel or the hyaluronic acid gel.

Topical Delivery of Coenzyme Q10-Loaded Microemulsion for Skin Regeneration

The aim of this study was to develop a coenzyme Q10 (CoQ10) microemulsion system with improved solubility, penetration, and wound healing efficacy. Based on the pseudo-ternary diagram, microemulsions containing isopropyl myristate (IPM), Cremophor EL^®, and Transcutol^® HP were selected and confirmed to be nanosized (<20 nm) and thermodynamically stable based on the dilution and thermodynamic stability tests. The CoQ10-loaded microemulsion with a surfactant/co-surfactant (S/CoS) ratio of 2:1 (w/w %) demonstrated a higher permeation efficacy compared to microemulsions with S/CoS ratio of 3:1 or 4:1 (w/w %). Additionally, the CoQ10-loaded microemulsion with an S/CoS ratio of 2:1 demonstrated a relatively rapid wound healing effect in keratinocytes and fibroblasts. Overall, these data suggest that a microemulsion based on IPM, Cremophor EL^®, and Transcutol^® HP could be an effective vehicle for the topical administration of CoQ10 and could be utilized for the application of other therapeutic agents that have difficulty in penetrating the skin.

Role of Omega-3 Fatty Acids and Butter Oil in Targeting Delivery of Donepezil Hydrochloride Microemulsion to Brain via the Intranasal Route: a Comparative Study

In order to investigate the possible role of butter oil (BO) and omega-3 fatty acids-rich fish oil (O3FO) in the delivery of donepezil hydrochloride microemulsion (DH-ME) to the brain via intranasal route, the present study was conducted. DH:BO and DH:O3FO binary mixtures (9:1 to 1:9) were prepared by simple physical mixing and subjected to in vitro diffusion study. Ratios of DH:BO and DH:O3FO, which showed the highest diffusion, were selected for further development of microemulsion (ME). Globule sizes of DH-BO-ME and DH-O3FO-ME were found to be 87.66 ± 5.23 nm and 88.59 ± 8.23 nm, respectively. Nasal histopathological study and in vitro cytotoxicity study revealed the safety of the formulation. Higher percentage of nasal diffusion was found with DH-BO-ME (71.22 ± 1.21%) and DH-O3FO-ME (62.16 ± 1.23%) in comparison to DH-ME (59.69 ± 1.74%) and DH solution (55.01 ± 1.19%), which was further supported by in vitro cell permeability study. After intranasal administration, %bioavailability of drug in the rat brain (Sprague-Dawley rats)(on the basis of DH-ME IV) was higher with DH-BO-ME (313.59 ± 12.98%) and DH-O3FO-ME (361.73 ± 15.15%) in comparison to DH-ME (168.62 ± 6.60%) and DH solution (8.960 ± 0.23%). The results of ex vivo diffusion study and in vivo pharmacokinetic study suggested that BO and O3FO helped in enhancing the nasal permeability and the brain uptake of drug when administered intranasally.

Method and its Composition for encapsulation, stabilization, and delivery of siRNA in Anionic polymeric nanoplex: An In vitro- In vivo Assessment

Small interfering RNA (siRNA) are synthetic RNA duplex designed to specifically knockdown the abnormal gene to treat a disease at cellular and molecular levels. In spite of their high potency, specificity, and therapeutic potential, the full-fledged utility of siRNA is predominantly limited to in vitro set-up. Till date, Onpattro is the only USFDA approved siRNA therapeutics available in the clinic. The lack of a reliable in vivo siRNA delivery carrier remains a foremost obstacle towards the clinical translation of siRNA therapeutics. To address the obstacles associated with siRNA delivery, we tested a dendrimer-templated polymeric approach involving a USFDA approved carrier (albumin) for in vitro as well as in vivo delivery of siRNA. The developed approach is simple in application, enhances the serum stability, avoids in vivo RNase-degradation and mediates cytosolic delivery of siRNA following the endosomal escape process. The successful in vitro and in vivo delivery of siRNA, as well as targeted gene knockdown potential, was demonstrated by HDAC4 inhibition in vitro diabetic nephropathy (DN) podocyte model as well as in vivo DN C57BL/6 mice model. The developed approach has been tested using HDAC4 siRNA as a model therapeutics, while the application can also be extended to other gene therapeutics including micro RNA (miRNA), plasmids oligonucleotides, etc.

Thermosensitive Nanocomposite Hydrogels for Intravitreal Delivery of Cefuroxime

Endophthalmitis is a rare, but serious, intravitreal inflammatory disorder that can arise after cataract surgery. The intracameral injection of 1 mg cefuroxime (CEF) followed by three-times daily antibiotic topical administration for a week is generally recognized as the routine method of prophylaxis after cataract surgery. This procedure is controversial because of both the low efficacy and the low adherence to therapy by elderly patients. A unique slow release antibiotic intravitreal injection could solve these problems. The objective of the present study was to design ophthalmic nanocomposite delivery systems based on in situ gelling formulations that undergo sol-to-gel transition upon change in temperature to prolong the effect of CEF. Oil in water (O/W) microemulsion (µE) and solid lipid nanoparticles (SLN), obtained with an innovative formulation technology called cold microemulsion dilution, were evaluated as ocular drug delivery systems for CEF. Drug entrapment efficiency up to 80% was possible by esterifying CEF with 1-dodecanol to obtain dodecyl-CEF (dCEF). Both dCEF-loaded SLN and µE were then added with Pluronic®F127 (20% w/v) to obtain a nanocomposite hydrogel-based long acting system. The prepared thermosensitive formulations were evaluated for their physical appearance, drug content, gelation temperature, injectability and rheological properties, in vitro release studies and stability studies. Moreover, cell proliferation assays on human retinal pigment epithelial ARPE-19 cells were performed to evaluate the influence of this innovative system on the cellular viability. In addition, minimal inhibitory concentration (MIC) was assessed for both CEF and dCEF, revealing the need of dCEF hydrolysis for the antimicrobial activity. Although further experimental investigations are required, the physico-chemical characterization of the nanocomposite hydrogels and the preliminary in vitro release studies highlighted the potential of these systems for the sustained release of CEF.

Novel Triamcinolone Acetonide-Loaded Liposomal Topical Formulation Improves Contrast Sensitivity Outcome After Femtosecond Laser-Assisted Cataract Surgery

Purpose: To assess visual results, macular modifications, and the incidence of clinically significant macular edema (CSME) in patients using a topical triamcinolone acetonide-loaded liposomal formulation (TA-LF) after femtosecond laser-assisted cataract surgery (FLACS). Methods: Fifty-six eyes after FLACS were selected. Twenty-eight eyes in the combined therapy group (P + N) were treated with prednisolone 1% and nepafenac 0.1% for 21 days postoperatively, whereas 28 eyes in the TA-LF group received a liposomal formulation containing 2 mg/mL of TA (0.2%) for the same period of time. Follow-up visits at 1 day, 6 weeks, and 12 weeks after surgery consisted of visual acuity, contrast sensitivity (CS), central foveal thickness (CFT), total macular volume (TMV) measurements, and the detection of CSME. Results: CS improved in the TA-LF group (basal value: 1.087 ± 0.339 vs. 1.276 ± 0.147 at week 12, P = 0.0346), whereas in the P + N group, CS was not different from the baseline (basal value: 1.130 ± 0.331 vs. 1.274 ± 0.133 at week 12, P = 0.1276). There were similar increases in postoperative CFT and TMV in both groups. CFT and TMV significantly correlate with CS only in the TA-LF group. The r² for CFT and CS was 0.1963 (P = 0.0206), whereas the r² for TMV and CS was 0.3615 (P = 0.0007) at 12 weeks. No difference was observed in the incidence of CSME between the groups. Conclusion: TA-LF is associated with better CS outcomes compared to combined therapy after FLACS.

Dendrimer grafted albumin nanoparticles for the treatment of post cerebral stroke damages: A proof of concept study

Stroke is the second largest disease of mortality. The biggest hurdle in designing effective brain drug delivery systems is offered by the blood-brain barrier (BBB), which is highly impermeable to many drugs. Albumin nanoparticles (NP) have gained attention due to their multiple ligand binding sites and long circulatory half-life. Citicoline (CIT) is reported to enhance the acetylcholine secretion in the brain and also helps in membrane repair and regeneration. However, the poor BBB permeation of CIT results in lower levels of CIT in the brain. This demands the development of a suitable delivery platform to completely realize the therapeutic benefit of CIT in stroke therapy. This investigation reports the synthesis and characterization of second generation (2.0 G) dendrimer Amplified Albumin (dAA) biopolymer by FTIR, MALDI-TOF, and surface charge (mV). Further, the synthesized biopolymer has been utilized to develop a CIT nanoformulation using a commercially translatable one-pot process. Release of CIT from biopolymer was performed within an acetate buffer at pH 5 and Phosphate buffer at pH 7.4. Further, we investigated the ability of biopolymer to permeate BBB by in vitro permeability assay in bEnd.3 cells. MTT assay of CIT-dAA-NP, CIT-ANP, and 2.0 G PAMAM dendrimers was performed in bEnd.3 cells. Therapeutic efficacy of the synthesized biopolymer was determined by VEGF gene expression within an in vitro hypoxia model in PC12 cells. Thus, this investigation resulted in biopolymers that can be used to deliver any therapeutic agent by altering the permeability of the BBB. Also, cationization by dendrimer grafting is one such strategy that may be used to cationize any other negatively charged polymer, such as albumin. The synthesized biopolymer is not limited to deliver molecules to the brain, but can also be used to increase the loading of negatively-charged drug molecules, siRNA, or any other oligonucleotide.

Fabrication of Mucoadhesive-Dendrimers as Solid Dosage Forms

Mucoadhesion has a potential role in the delivery of pharmaceutical medicaments via various routes of administration, viz. oral, nasal, vaginal, and buccal. Mucoadhesion provides controlled drug delivery, sustained drug delivery, and local or site-specific drug delivery. This chapter focuses on the mechanism of bio-adhesion to glycoprotein layer of mucosal membrane. Some of the gastric mucoadhesive solid dosage forms of nanocarrier, viz. nanoparticle, microsphere, and nanofibers, undergo evaluation of mucoadhesive parameters. That includes mucoadhesive strength, tensile strength, swelling index, stability studies, in vivo study, etc. The oral route is the most desirable way among intravenous, subcutaneous, intramuscular, intranasal, intravaginal, etc. for drug delivery and because of patient compliance. One of the novel approaches is where nanocarrier is loaded in the solid dosage form for effective drug action and enhanced local delivery of a drug. Mainly this chapter explains about dendrimer-based oral solid dosage form (tablet) employing mucoadhesive polymers with an aim to improve retention time of drug at desired sites. Dendrimer-loaded mucoadhesive tablets promise controlled drug delivery with a gastro-retentive property, higher drug incorporation, ease of formulation development, and accessible absorption, owing to adjacent interaction with a biological membrane and prolonged retention to mucosa providing higher bioavailability of drugs.

'Dendrimer-Cationized-Albumin' encrusted polymeric nanoparticle improves BBB penetration and anticancer activity of doxorubicin

Glioblastoma is one of the most rapaciously growing cancer within the brain with an average lifespan of 12-15 months (5-year survival <3-4%). Doxorubicin (DOX) is clinically utilized as a first line drug in the treatment of Glioblastoma, however, its restricted entry into the brain via the blood-brain barrier (BBB), limited blood-tumor barrier (BTB) permeability, hemotoxicity, short mean half-life of 1-3 hr as well as rapid body clearance results in tremendously diminished bioactivity in glioblastoma. Dendrimer-Cationized-Albumin (dCatAlb) was synthesized following the carboxyl activation technique and the synthesized biopolymer was characterized by FTIR, MALDI-TOF and zeta potential. The prepared dCatAlb was encrusted on DOX-loaded PLGA nanoparticle core to develop a novel hybrid DOX nanoformulation (dCatAlb-pDNP; particle size: 156 ± 10.85 nm; ƺ: -10.0 ± 2.1 mV surface charge). The formulated dCatAlb-pDNP showed a unique pH-dependent DOX release profile, diminished hemolytic toxicity, higher drug uptake (<0.001) and cytotoxicity in U87MG glioblastoma cells, increase levels of caspase-3 gene in U87MG cells (approximately 5.35-fold higher) inferred that anticancer activity is primarily taking place through caspase-mediated apoptosis mechanism. The developed novel DOX nanoformulation also showed superior trans-epithelial permeation transport across monolayer bEnd.3 cells as well as notable biocompatibility and stability. The dCatAlb-pDNP showed enhanced BBB permeation efficacy as confirmed permeation assay in bEnd.3 cell-based model. The long-term formulation stability of developed nanoformulations was studied by storing them at 5 ± 2 °C and 30 ± 2 °C/60 ± 5% Relative Humidity (% RH) in the stability chamber for a period of 60 days (ICHQ1A (R2)). The outcomes of this investigation evidently indicate that dCatAlb-pDNP offers superior anticancer activity of DOX in glioblastoma cells while significantly improving its BBB permeation. The developed formulation is a biocompatible, safer and commercially viable approach to delivering DOX selectively in sustained manner glioblastoma while countering its hemolytic toxic effect, which is a major ongoing issue with conventional DOX injectable available in the market today.