VB12-coated Gel-Core-SLN containing insulin: Another way to improve oral absorption

Solid Lipid Nanoparticles as an Innovative Lipidic Drug Delivery System

In order to overcome some of the drawbacks of traditional formulations, increasing emphasis has recently been paid to lipid-based drug delivery systems. Solid lipid nanoparticles (SLNs) are promising delivery methods, and they hold promise because of their simplicity in production, capacity to scale up, biocompatibility, and biodegradability of formulation components. Other benefits could be connected to a particular route of administration or the makeup of the ingredients being placed into these delivery systems. This article aims to review the significance of solid lipid nanocarriers, their benefits and drawbacks, as well as their types, compositions, methods of preparation, mechanisms of drug release, characterization, routes of administration, and applications in a variety of delivery systems with a focus on their efficacy.

Nanoparticle and microparticle-based systems for enhanced oral insulin delivery: A systematic review and meta-analysis

Diabetes mellitus (DM) prevalence is rising worldwide. Current therapies comprising subcutaneous insulin injections can cause adverse effects such as lipodystrophy, local reactions like redness and swelling, fluid retention, and allergic reactions. Nanoparticle carriers for oral insulin are groundbreaking compared to existing methods because they are non-invasive treatments, showing operational convenience, controlled release profile, and ability to simulate the physiological delivery route into the bloodstream. These systems improve patient adherence and have demonstrated the potential to lower blood glucose levels in DM. We present a systematic review and meta-analysis aimed at compiling relevant data to pave the way for developing innovative nano- and microparticles for the oral delivery of insulin. Our analysis of 85 articles revealed that the diminution of glucose levels is not proportional to the administered insulin dosage, which ranged from 1 to 120 International Units (IU). The meta-analysis data indicated that 25 IU of encapsulated porcine insulin did not produce a statistically significant outcome (p = 0.93). In contrast, a dosage of 30 IU was efficacious in eliciting an optimal hypoglycemic effect compared to excipient controls. Parameters such as a high degree of encapsulation (~ 90%), particle size (200-400 nm), and polydispersity index (0.086-0.3) are all associated with lower blood glucose levels. These parameters were also significant in the linear regression analysis. Among the excipients employed, chitosan emerged as a prevalent excipient in formulations due to its biocompatible and biodegradable properties and its ability to establish stable polymeric matrices. Even though oral insulin administration is a promising therapeutic method, it cannot guarantee preclinical safety and therapeutic efficacy yet in regulating glucose levels in diabetic conditions.

Tailored Polymersomes for Enhanced Oral Drug Delivery: pH-Sensitive Systems for Intestinal Delivery of Immunosuppressants

Ensuring precise drug release at target sites is crucial for effective treatment. Here, pH-responsive nanoparticles for oral administration of mycophenolate mofetil, an alternative therapy for patients with inflammatory bowel disease unresponsive to conventional treatments is developed. However, its oral administration presents challenges due to its low solubility in the small intestine and high solubility and absorption in the stomach. Therefore, this aim is to design a drug delivery system capable of maintaining drug solubility compared to the free drug while delaying absorption from the stomach to the intestine. Successful synthesis and assembly of a block copolymer incorporating a pH-responsive functional group is achieved. Dynamic light scattering indicated a significant change in hydrodynamic size when the pH exceeded 6.5, confirming successful incorporation of the pH-responsive group. Encapsulation and controlled release of mycophenolate mofetil are efficiently demonstrated, with 90% release observed at intestinal pH. In vitro cell culture studies confirmed biocompatibility, showing no toxicity or adverse effects on Caco-2 cells. In vivo oral rat studies indicated reduced drug absorption in the stomach and enhanced absorption in the small intestine with the developed formulation. This research presents a promising drug delivery system with potential applications in the treatment of inflammatory bowel disease.

Advances in Nanomedicine for Precision Insulin Delivery

Diabetes mellitus, which comprises a group of metabolic disorders affecting carbohydrate metabolism, is characterized by improper glucose utilization and excessive production, leading to hyperglycemia. The global prevalence of diabetes is rising, with projections indicating it will affect 783.2 million people by 2045. Insulin treatment is crucial, especially for type 1 diabetes, due to the lack of β-cell function. Intensive insulin therapy, involving multiple daily injections or continuous subcutaneous insulin infusion, has proven effective in reducing microvascular complications but poses a higher risk of severe hypoglycemia. Recent advancements in insulin formulations and delivery methods, such as ultra-rapid-acting analogs and inhaled insulin, offer potential benefits in terms of reducing hypoglycemia and improving glycemic control. However, the traditional subcutaneous injection method has drawbacks, including patient compliance issues and associated complications. Nanomedicine presents innovative solutions to these challenges, offering promising avenues for overcoming current drug limitations, enhancing cellular uptake, and improving pharmacokinetics and pharmacodynamics. Various nanocarriers, including liposomes, chitosan, and PLGA, provide protection against enzymatic degradation, improving drug stability and controlled release. These nanocarriers offer unique advantages, ranging from enhanced bioavailability and sustained release to specific targeting capabilities. While oral insulin delivery is being explored for better patient adherence and cost-effectiveness, other nanomedicine-based methods also show promise in improving delivery efficiency and patient outcomes. Safety concerns, including potential toxicity and immunogenicity issues, must be addressed, with the FDA providing guidance for the safe development of nanotechnology-based products. Future directions in nanomedicine will focus on creating next-generation nanocarriers with precise targeting, real-time monitoring, and stimuli-responsive features to optimize diabetes treatment outcomes and patient safety. This review delves into the current state of nanomedicine for insulin delivery, examining various types of nanocarriers and their mechanisms of action, and discussing the challenges and future directions in developing safe and effective nanomedicine-based therapies for diabetes management.

Anti-inflammatory Fucoidan-ConA oral insulin nanosystems for smart blood glucose regulation

The smart oral administration Insulin device has the potential to improve glycemic management. It can reduce the risk of hypoglycemia associated with exogenous Insulin (INS) therapy while also avoiding many of the disadvantages associated with subcutaneous injections. Furthermore, diabetes mellitus (DM) is an endocrine illness characterized by inflammation, and it is critical to minimize the amount of inflammatory markers in diabetic patients while maintaining average blood glucose. In this study, a responsive nanosystem vitamin B12-Fucoidan-Concanavalin A (VB12-FU-ConA NPs) with anti-inflammatory action was developed for smart oral delivery of Insulin. Con A has high sensitivity and strong specificity as a glucose-responsive material. Fucoidan has anti-inflammatory, immunomodulatory, and hypoglycemic functions, and it can bind to Con A to form a reversible complex. Under high glucose conditions, free glucose competitively binds to Con A, which swells the nanocarrier and promotes Insulin release. Furthermore, in the low pH environment of the gastrointestinal tract, positively charged VB12 and anionic fucoidan bind tightly to protect the Insulin wrapped in the carrier, and VB12 can also bind to intestinal epithelial factors to improve transit rate, thereby promoting INS absorption. In vitro tests showed that the release of nanoparticles in hyperglycemic solutions was significantly higher than the drug release in normoglycemic conditions. Oral delivery of the nanosystems dramatically lowered blood glucose levels in type I diabetic mice (T1DM) during in vivo pharmacodynamics, minimizing the risk of hypoglycemia. Blood glucose levels reached a minimum of 8.1 ± 0.4 mmol/L after 8 h. Administering the nanosystem orally notably decreased the serum levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in diabetic mice. The nano delivery system can be degraded and metabolized in the intestinal tract after being taken orally, demonstrating good biodegradability and biosafety. In conclusion, the present study showed that VB12-FU-ConA nanocarriers are expected to be a novel system for rationalizing blood glucose.

Chemistry and Art of Developing Lipid Nanoparticles for Biologics Delivery: Focus on Development and Scale-Up

Lipid nanoparticles (LNPs) have gained prominence as primary carriers for delivering a diverse array of therapeutic agents. Biological products have achieved a solid presence in clinical settings, and the anticipation of creating novel variants is increasing. These products predominantly encompass therapeutic proteins, nucleic acids and messenger RNA. The advancement of efficient LNP-based delivery systems for biologics that can overcome their limitations remains a highly favorable formulation strategy. Moreover, given their small size, biocompatibility, and biodegradation, LNPs can proficiently transport therapeutic moiety into the cells without significant toxicity and adverse reactions. This is especially crucial for the existing and upcoming biopharmaceuticals since large molecules as a group present several challenges that can be overcome by LNPs. This review describes the LNP technology for the delivery of biologics and summarizes the developments in the chemistry, manufacturing, and characterization of lipids used in the development of LNPs for biologics. Finally, we present a perspective on the potential opportunities and the current challenges pertaining to LNP technology.

Mechanisms of Nanoparticle Transport across Intestinal Tissue: An Oral Delivery Perspective

Oral drug administration has been a popular choice due to patient compliance and limited clinical resources. Orally delivered drugs must circumvent the harsh gastrointestinal (GI) environment to effectively enter the systemic circulation. The GI tract has a number of structural and physiological barriers that limit drug bioavailability including mucus, the tightly regulated epithelial layer, immune cells, and associated vasculature. Nanoparticles have been used to enhance oral bioavailability of drugs, as they can act as a shield to the harsh GI environment and prevent early degradation while also increasing uptake and transport of drugs across the intestinal epithelium. Evidence suggests that different nanoparticle formulations may be transported via different intracellular mechanisms to cross the intestinal epithelium. Despite the existence of a significant body of work on intestinal transport of nanoparticles, many key questions remain: What causes the poor bioavailability of the oral drugs? What factors contribute to the ability of a nanoparticle to cross different intestinal barriers? Do nanoparticle properties such as size and charge influence the type of endocytic pathways taken? In this Review, we summarize the different components of intestinal barriers and the types of nanoparticles developed for oral delivery. In particular, we focus on the various intracellular pathways used in nanoparticle internalization and nanoparticle or cargo translocation across the epithelium. Understanding the gut barrier, nanoparticle characteristics, and transport pathways may lead to the development of more therapeutically useful nanoparticles as drug carriers.

Solid lipid nanoparticles: a promising tool for insulin delivery

INTRODUCTION

Insulin plays a critical role in metabolism modulation including carbohydrate, lipid, and protein metabolism. There is room to improve insulin delivery but optimizing the best carrier remains challenging. Traditional and conventional approaches for insulin delivery do not emulate the normal fate of insulin release in the body. Despite extensive research attempts to overcome this and other challenges, the goal of achieving optimal insulin delivery that emulates the natural system remains unresolved.

AREAS COVERED

Solid Lipid Nanoparticles (SLNs) may provide a solution, because they are nontoxic, biocompatible, and straightforward to formulate thus providing a promising platform for achieving targeted and controlled delivery of various therapeutic agents. This review aims to provide an overview on the suitability and application of SLNs for insulin delivery. A special emphasis is placed on the biopharmaceutical aspects of insulin loaded SLNs which have not been explored in detail to date.

EXPERT OPINION

SLNs have proven to be safe and versatile drug delivery systems suitable for insulin delivery and capable of improving the efficacy and pharmacokinetic profile of encapsulated insulin. There is still some work to be done to fully explore SLNs' true potential as drug delivery and specifically insulin delivery vehicles suitable for clinical use.

Hijacking the intrinsic vitamin B12 pathway for the oral delivery of nanoparticles, resulting in enhanced in vivo anti-leishmanial activity

Surface-functionalized vitamin B₁₂ (VB₁₂) biocompatible nanoparticles exploit the well-characterized uptake pathway of VB₁₂, shielding it from enzymatic degradation and inadequate absorption. In this perspective, subsequent to escalated mucus interaction and diffusion analysis, the nanoparticles were investigated by immunostaining with the anti-CD320 antibody, and their internalization mechanisms were examined by selectively blocking specific uptake processes. It was observed that their internalization occurred via an energy-dependent clathrin-mediated mechanism, simultaneously highlighting their remarkable ability to bypass the P-glycoprotein efflux. In particular, the synthesized nanoparticles were evaluated for their cytocompatibility by analyzing cellular proliferation, membrane viscoelasticity, and fluidity by fluorescence recovery after photobleaching and oxidative-stress detection, making them well-suited for successful translation to a clinical setup. Our previous in vitro antileishmanial results were paramount for their further in vivo and toxicity analysis, demonstrating their targeted therapeutic efficiency. The augmented surface hydrophilicity, which is attributed to VB₁₂, and monomerization of amphotericin B in the lipid core strengthened the oral bioavailability and stability of the nanoparticles, as evidenced by the fluorescence resonance energy transfer analysis.

Mechanism of Enhanced Oral Absorption of a Nano-Drug Delivery System Loaded with Trimethyl Chitosan Derivatives

Introduction

In the previous study, nanoparticles coated with trimethyl chitosan (TMC) derivatives (PPTT-NPs) could promote the oral bioavailability of panax notoginseng saponins (PNS). Herein, we chose PPTT-NPs as a model drug to study the property and mechanism of intestinal absorption in vitro and in vivo.

Methods

The stability of PPTT-NPs was evaluated using simulated gastric fluid and simulated intestinal fluid. The uptake and transport of PPTT-NPs were investigated in Caco-2 and Caco-2&HT29 co-culture cells. The biosafety, intestinal permeability, adhesion, and absorption mechanism of PPTT-NPs were investigated using SD rats in vivo. The live imaging and biodistribution of PPTT-NPs were observed by IVIS. Furthermore, the effects on CYP3A4 of PPTT-NPs were investigated using testosterone as the probe substrate.

Results

The results of the stability assay showed that PPTT-NPs had a strong tolerance to the pH and digestive enzymes in the gastrointestinal environment. In vitro cell experiments showed that the uptake of drugs exhibited a time-dependent. When the ratio of TMC-VB₁₂ and TMC-Cys was 1:3, the uptake capacity of PPTT-NPs was the highest. PPTT-NPs could enhance the paracellular transport of drugs by reversibly opening a tight junction. Animal experiments demonstrated that PPTT-NPs have good biological safety. PPTT-NPs had good adhesion and permeability to small intestinal mucosa. Meanwhile, PPTT-NPs needed energy and various protein to participate in the uptake of drugs. The live imaging of NPs illustrated that PPTT-NPs could prolong the residence time in the intestine. Moreover, TMC-VB₁₂ and TMC-Cys could reduce the metabolism of drugs by inhibiting CYP3A4 to a certain extent.

Conclusion

The results show that TMC-VB₁₂ and TMC-Cys are effective in the transport of PPTT-NPs. PPTT-NPs can increase the intestinal adhesion of drugs and exert high permeation by intestinal enterocytes which demonstrate significant and efficient potential for oral delivery of the BCS III drugs.

Dual crosslinking of folic acid-modified pectin nanoparticles for enhanced oral insulin delivery

Pectin-based drug delivery systems hold great potential for oral insulin delivery, since they possess excellent gelling property, good mucoadhesion and high stability in the gastrointestinal (GI) tract. However, lack of enterocyte targeting ability and premature drug release in the upper GI tract of the susceptible ionic-crosslinked pectin matrices are two major problems to be solved. To address these issues, we developed folic acid (FA)-modified pectin nanoparticles (INS/DFAN) as insulin delivery vehicles by a dual-crosslinking method using calcium ions and adipic dihydrazide (ADH) as crosslinkers. In vitro studies indicated insulin release behaviors of INS/DFAN depended on COOH/ADH molar ratio in the dual-crosslinking process. INS/DFAN effectively prevented premature insulin release in simulated GI fluids compared to ionic-crosslinked nanoparticles (INS/FAN). At an optimized COOH/ADH molar ratio, INS/DFAN with FA graft ratio of 18.2% exhibited a relatively small particle size, high encapsulation efficiency and excellent stability. Cellular uptake of INS/DFAN was FA graft ratio dependent when it was at/below 18.2%. Uptake mechanism and intestinal distribution studies demonstrated the enhanced insulin transepithelial transport by INS/DFAN via FA carrier-mediated transport pathway. In vivo studies revealed that orally-administered INS/DFAN produced a significant reduction in blood glucose levels and further improved insulin bioavailability in type I diabetic rats compared to INS/FAN. Taken together, the combination of dual crosslinking and FA modification is an effective strategy to develop pectin nano-vehicles for enhanced oral insulin delivery.

Physicochemical Characterizations and Pharmacokinetic Evaluation of Pentazocine Solid Lipid Nanoparticles against Inflammatory Pain Model

Pentazocine (PTZ), a narcotic-antagonist analgesic, has been extensively used in the treatment of initial carcinogenic or postoperative pain. Hepatic first-pass metabolism results in low oral bioavailability and high dose wastage. Herein, 10 mg (-)-Pentazocine (HPLC-grade) was incorporated to solid lipid nanoparticles (SLNs) using a double water-oil-water (w/o/w) emulsion by solvent emulsification-evaporation technique, followed by high shear homogenization to augment its oral bioavailability, considering the lymphatic uptake. The resulting SLNs were characterized for zeta potential (ZP), particle size (PS), and polydispersity index (PDI) using a zetasizer. The entrapment efficiency (EE) and loading capacity (LC) were calculated. Chemical interactions, through the identification of active functional groups, were assessed by Fourier-transformed infrared (FTIR) spectroscopy. The nature (crystallinity) of the SLNs was determined by X-ray diffractometry (XRD). The surface morphology was depicted by transmission electron microscopy (TEM). In vitro (in Caco-2 cells) and in vivo (in male Wistar rats) investigations were carried out to evaluate the PTZ release behavior and stability, as well as the cellular permeation, cytotoxicity, systemic pharmacokinetics, antinociceptive, anti-inflammatory, and antioxidative activities of PTZ-loaded SLNs, mainly compared to free PTZ (marketed conventional dosage form). The optimized PTZ-loaded SLN2 showed significantly higher in vitro cellular permeation and negligible cytotoxicity. The in vivo bioavailability and pharmacokinetics parameters (t1/2, Cmax) of the PTZ-loaded SLNs were also significantly improved, and the nociception and inflammation, following carrageenan-induced inflammatory pain, were markedly reduced. Concordantly, PTZ-loaded SLNs showed drastic reduction in the oxidative stress (e.g., malonaldehyde (MDA)) and proinflammatory cytokines (e.g., Interleukin (IL)-1β, -6, and TNF-α). The histological features of the paw tissue following, carrageenan-induced inflammation, were significantly improved. Taken together, the results demonstrated that PTZ-loaded SLNs can improve the bioavailability of PTZ by bypassing the hepatic metabolism via the lymphatic uptake, for controlled and sustained drug delivery.

Nanoparticles composed of the tea polysaccharide-complexed cationic vitamin B12-conjugated glycogen derivative

Tea polysaccharides exhibit multiple important bioactivities, but very few of them can be absorbed through the small intestine. To enhance the absorption efficacy of tea polysaccharides, a cationic vitamin B12-conjugated glycogen derivative bearing the diethylenetriamine residues (VB12-DETA-Gly) was synthesized and characterized using FTIR, 1H NMR, and UV-vis spectroscopy. An acidic tea polysaccharide (TPSA) was isolated from green tea. The TPSA/VB12-DETA-Gly complexed nanoparticles were prepared, which showed positive zeta potentials and were irregular spherical nanoparticles in the sizes of 50-100 nm. To enable the fluorescence and UV-vis absorption properties of TPSA, a Congo red residue-conjugated TPSA derivative (CR-TPSA) was synthesized. The interactions and complexation mechanism between the CR-TPSA and the VB12-DETA-Gly derivatives were investigated using fluorescence spectroscopy, resonance light scattering spectroscopy, and UV-vis spectroscopy. The results indicated that the electrostatic interaction could play a major role during the CR-TPSA and VB12-DETA-Gly-II complexation processes. The TPSA/VB12-DETA-Gly nanoparticles were nontoxic and exhibited targeted endocytosis for the Caco-2 cells, and showed high permeation through intestinal enterocytes using the Caco-2 cell model. Therefore, they exhibit potential for enhancing the absorption efficacy of tea polysaccharides through the small intestinal mucosa.

A comparison study of lipid and polymeric nanoparticles in the nasal delivery of meloxicam: Formulation, characterization, and in vitro evaluation

With the increasingly widespread of central nervous system (CNS) disorders and the lack of sufficiently effective medication, meloxicam (MEL) has been reported as a possible medication for Alzheimer's disease (AD) management. Unfortunately, following the conventional application routes, the low brain bioavailability of MEL forms a significant limitation. The intranasal (IN) administration route is considered revolutionary for CNS medications delivery. The objective of the present study was to develop two types of nanocarriers, poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) and solid lipid nanoparticles (SLNs), for the IN delivery of MEL adapting the Quality by Design approach (QbD). Turning then to further enhance the optimized nanoformulation behavior by chitosan-coating. SLNs showed higher encapsulation efficacy (EE) and drug loading (DL) than PLGA NPs 87.26% (EE) and 2.67% (DL); 72.23% (EE) and 2.55% (DL), respectively. MEL encapsulated into the nanoformulations improved in vitro release, mucoadhesion, and permeation behavior compared to the native drug with greater superiority of chitosan-coated SLNs (C-SLNs). In vitro-in vivo correlation (IVIVC) results estimated a significant in vivo brain distribution of the nanoformulations compared to native MEL with estimated greater potential in the C-SLNs. Hence, MEL encapsulation into C-SLNs towards IN route can be promising in enhancing its brain bioavailability.

Recent advances of nanomedicine-based strategies in diabetes and complications management: Diagnostics, monitoring, and therapeutics

Diabetes mellitus (DM) is a metabolic disorder characterized by the presence of chronic hyperglycemia driven by insulin deficiency or resistance, imposing a significant global burden affecting 463 million people worldwide in 2019. This review has comprehensively summarized the application of nanomedicine with accurate, patient-friendly, real-time properties in the field of diabetes diagnosis and monitoring, and emphatically discussed the unique potential of various nanomedicine carriers (e.g., polymeric nanoparticles, liposomes, micelles, microparticles, microneedles, etc.) in the management of diabetes and complications. Novel delivery systems have been developed with improved pharmacokinetics and pharmacodynamics, excellent drug biodistribution, biocompatibility, and therapeutic efficacy, long-term action safety, as well as the improved production methods. Furthermore, the effective nanomedicine for the treatment of several major diabetic complications with significantly improved life qualities of diabetic patients were discussed in detail. Going through the literature review, several critical issues of the nanomedicine-based strategies applications need to be addressed such as stabilities and long-term safety effects in vivo, the deficiency of standard for formulation administration, feasibility of scale-up, etc. Overall, the review provides an insight into the design, advantages and limitations of novel nanomedicine application in the diagnostics, monitoring, and therapeutics of DM.

Formulation, characterization and in vitro anti-leishmanial evaluation of amphotericin B loaded solid lipid nanoparticles coated with vitamin B12-stearic acid conjugate

Despite the advancement of new anti-leishmanials, amphotericin B (AmB) prevails as one of the most potent agent in the treatment of visceral leishmaniasis (VL), a neglected tropical disease affecting mostly poverty ridden and underdeveloped regions of the globe. Nonetheless, many patients display intolerance to parenteral AmB, notably at higher dosages. Also, conventional AmB presents an apparently poor absorption. Therefore, to improve AmB bioavailability and overcome multiple barriers for oral delivery of AmB, we fabricated a promising vitamin B₁₂-stearic acid (VBS) conjugate coated solid lipid nanoparticles (SLNs) encapsulated with AmB (VBS-AmB-SLNs) by a combination of double emulsion solvent evaporation and thermal sensitive hydrogel techniques. VBS-AmB-SLNs showed a particle size of 306.66 ± 3.35 nm with polydispersity index of 0.335 ± 0.08 while the encapsulation efficiency and drug loading was observed to be 97.99 ± 1.6% and 38.5 ± 5.6% respectively. In vitro drug release showed a biphasic release pattern and chemical stability of AmB was ensured against simulated gastrointestinal fluids. Cellular uptake studies confirmed complete internalization of the formulation. Anti-leishmanial evaluation against intramacrophage amastigotes showed an enhanced efficacy of 94% which was significantly (P < 0.01) higher than conventional AmB without showing any toxic effects on J774A.1 cells. VBS-AmB-SLNs could serve as a potential therapeutic strategy against VL.

Formulation and in-vivo Evaluation of Novel Topical Gel of Lopinavir for Targeting HIV

BACKGROUND

Lopinavir is a specific reversible inhibitor of the enzyme HIV protease with mean oral bioavailability of less than 20 % due to extensive hepatic metabolism by cytochrome P450 3A4. The reported half-life of Lopinavir is 5-6 hours and the maximum recommended daily dose is 400 mg/day. All the marketed tablet and capsule formulations of lopinavir are generally combined with Ritonavir, a potent inhibitor of cytochrome P450 3A4, to minimize presystemic metabolism of lopinavir. Hence, to overcome limitations associated with oral administration of lopinavir and to promote single drug administration, utilization of vesicular nanocarriers through topical route could prove to be effective, as the approach combines the inherent advantages of topical route and the drug-carrying potential of vesicular nanocarriers across the tough and otherwise impervious skin barrier layer, i.e., stratum corneum.

OBJECTIVE

The objective was to develop solid lipid nanoparticles (SLN) of lopinavir and formulate a topical gel for improved systemic bioavailability of lopinavir.

METHOD

SLNs were prepared using high-pressure homogenization technique and optimized. The nanoparticles were characterized by SEM to confirm their spherical shape. Differential Scanning Calorimetry (DSC) analysis was carried out to ensure the entrapment of drug inside the SLNs. A comparative evaluation was done between SLN based gel and plain gel of drug by performing exvivo skin permeation studies using Franz diffusion cell. To explore the potential of topical route, invivo bioavailability study was conducted in male Wistar rats.

RESULTS

The optimized formulation composed of Compritol 888ATO (0.5 %) as a lipid, Poloxamer 407 (0.25 %) as a surfactant and Labrasol (0.25 %) as a co-surfactant gave the maximum entrapment of 69.78 % with mean particle size of 48.86nm. The plain gel of the drug gave a release of 98.406 ± 0.007 % at the end of 4hours whereas SLN based gel gave a more sustained release of 71.197 ±0.006 % at the end of 12hours ex-vivo. As observed from the results of in-vivo studies, highest Cmax was found with SLN based gel (20.3127 ± 0.6056) µg/ml as compared to plain gel (8.0655 ± 1.6369) µg/ml and oral suspension (4.2550 ± 16.380) µg/ml of the drug. Also, the AUC was higher in the case of SLN based gel indicating good bioavailability as compared to oral suspension and plain gel of drug.

CONCLUSION

Lopinavir SLN based gel was found to have modified drug release pattern providing sustained release as compared to plain drug gel. This indicates that Lopinavir when given topically has a good potential to target the HIV as compared to when given orally.

Role of nanostructures in improvising oral medicine

The most preferable mode of drugs administration is via the oral route but physiological barriers such as pH, enzymatic degradation etc. limit the absolute use of this route. Herein lies the importance of nanotechnology having a wide range of applications in the field of nano-medicine, particularly in drug delivery systems. The exclusive properties particularly small size and high surface area (which can be modified as required), exhibited by these nanoparticlesrender these structures more suitable for the purpose of drug delivery. Various nanostructures, like liposomes, dendrimers, mesoporous silica nanoparticles, etc. have been designed for the said purpose. These nanostructures have several advantages over traditional administration of medicine. Apart from overcoming the pharmacokinetic and pharmacodynamics limitations of many potential therapeutic molecules, they may also be useful for advanced drug delivery purposes like targeted drug delivery, controlled release, enhanced permeability and retention (EPR) effect. In this review, we attempt to describe an up-to-date knowledge on various strategically devised nanostructures to overcome the problems related to oral drug administration.

Solid nanoparticles for oral antimicrobial drug delivery: a review

Most microbial infectious diseases can be treated successfully with the remarkable array of antimicrobials current available; however, antimicrobial resistance, adverse effects, and the high cost of antimicrobials are crucial health challenges worldwide. One of the common efforts in addressing this issue lies in improving the existing antibacterial delivery systems. Solid nanoparticles (SNPs) have been widely used as promising strategies to overcome these challenges. In addition, oral delivery is the most common method of drug administration with high levels of patient acceptance. Formulation into NPs can improve drug stability in the harsh gastrointestinal (GI) tract environment, providing opportunities for targeting specific sites in the GI tract, increasing drug solubility and bioavailability, and providing sustained release in the GI tract. Here, we discuss SNPs for the oral delivery of antimicrobials, including solid lipid NPs (SLNs), polymeric NPs (PNs), mesoporous silica NPs (MSNs) and hybrid NPs (HNs). We also discussed about the role of nanotechnology in IV to oral antimicrobial therapy development as well as challenges, clinical transformation, and limitations of SNPs for oral antimicrobial drug delivery.

Intestinal uptake and transport of albumin nanoparticles: potential for oral delivery

AIM

To explore the potential of albumin nanoparticles for oral drug delivery.

METHODS

Sub-150 nm human serum albumin nanoparticles were fabricated via a desolvation technique. Nanoparticle cell uptake and epithelial translocation were tested in Caco-2 monolayers, while comparing with albumin solution.

RESULTS

Data suggest epithelial transcytosis of albumin, applied in solution form, via neonatal Fc receptor. Cell uptake of albumin nanoparticles demonstrated behaviors indicating a different cell uptake pathway compared with albumin solution. Importantly, application of equivalent concentrations of albumin solution or nanoparticles resulted in higher epithelial transport capacity of the latter, suggesting improvement of intestinal delivery via nanoformulation.

CONCLUSION

This study highlights for the first time that simply fabricated, nontoxic human serum albumin nanoparticles may find application in oral drug delivery.

The role of mucus as an invisible cloak to transepithelial drug delivery by nanoparticles

Mucosal administration of drugs and drug delivery systems has gained increasing interest. However, nanoparticles intended to protect and deliver drugs to epithelial surfaces require transport through the surface-lining mucus. Translation from bench to bedside is particularly challenging for mucosal administration since a variety of parameters will influence the specific barrier properties of the mucus including the luminal fluids, the microbiota, the mucus composition and clearance rate, and the condition of the underlying epithelia. Besides, after administration, nanoparticles interact with the mucosal components, forming a biomolecular corona that modulates their behavior and fate after mucosal administration. These interactions are greatly influenced by the nanoparticle properties, and therefore different designs and surface-engineering strategies have been proposed. Overall, it is essential to evaluate these biomolecule-nanoparticle interactions by complementary techniques using complex and relevant mucus barrier matrices.

Enhancement of scutellarin oral delivery efficacy by vitamin B12-modified amphiphilic chitosan derivatives to treat type II diabetes induced-retinopathy

BACKGROUND

Diabetic retinopathy is the most common complication in diabetic patients relates to high expression of VEGF and microaneurysms. Scutellarin (Scu) turned out to be effective against diabetes related vascular endothelial cell dysfunction. However, its clinical applications have been limited by its low bioavailability. In this study, we formulated and characterized a novel intestinal target nanoparticle carrier based on amphiphilic chitosan derivatives (Chit-DC-VB12) loaded with scutellarin to enhance its bioavailability and then evaluated its therapeutic effect in experimental diabetic retinopathy model.

RESULTS

Chit-DC-VB12 nanoparticles showed low toxicity toward the human colon adenocarcinoma (Caco-2) cells and zebra fish within concentration of 250 μg/ml, owing to good biocompatibility of chitosan. The scutellarin-loaded Chit-DC-VB12 nanoparticles (Chit-DC-VB12-Scu) were then prepared by self-assembly in aqueous solution. Scanning electron microscopy and dynamic light scattering analysis indicated that the Chit-DC-VB12-Scu nanoparticles were spherical particles in the sizes ranging from 150 to 250 nm. The Chit-DC-VB12-Scu nanoparticles exhibited high permeation in Caco-2 cell, indicated it could be beneficial to be absorbed in humans. We also found that Chit-DC-VB12 nanoparticles had a high cellular uptake. Bioavailability studies were performed in Sprague-Dawley rats, which present the area under the curve of scutellarin of Chit-DC-VB12-Scu was two to threefolds greater than that of free scutellarin alone. Further to assess the therapeutic efficacy of diabetic retinopathy, we showed Chit-DC-VB12-Scu down-regulated central retinal artery resistivity index and the expression of angiogenesis proteins (VEGF, VEGFR2, and vWF) of retinas in type II diabetic rats.

CONCLUSIONS

Chit-DC-VB12 nanoparticles loaded with scutellarin have better bioavailability and cellular uptake efficiency than Scu, while Chit-DC-VB12-Scu nanoparticles alleviated the structural disorder of intraretinal neovessels in the retina induced by diabetes, and it also inhibited the retinal neovascularization via down-regulated the expression of angiogenesis proteins. In conclusion, the Chit-DC-VB12 nanoparticles enhanced scutellarin oral delivery efficacy and exhibited potential as small intestinal target promising nano-carriers for treatment of type II diabetes induced-retinopathy.

Advances in Hybrid Polymer-Based Materials for Sustained Drug Release

The use of biomaterials composed of organic pristine components has been successfully described in several purposes, such as tissue engineering and drug delivery. Drug delivery systems (DDS) have shown several advantages over traditional drug therapy, such as greater therapeutic efficacy, prolonged delivery profile, and reduced drug toxicity, as evidenced by in vitro and in vivo studies as well as clinical trials. Despite that, there is no perfect delivery carrier, and issues such as undesirable viscosity and physicochemical stability or inability to efficiently encapsulate hydrophilic/hydrophobic molecules still persist, limiting DDS applications. To overcome that, biohybrid systems, originating from the synergistic assembly of polymers and other organic materials such as proteins and lipids, have recently been described, yielding molecularly planned biohybrid systems that are able to optimize structures to easily interact with the targets. This work revised the biohybrid DDS clarifying their advantages, limitations, and future perspectives in an attempt to contribute to further research of innovative and safe biohybrid polymer-based system as biomaterials for the sustained release of active molecules.

Oral absorption of peptides and nanoparticles across the human intestine: Opportunities, limitations and studies in human tissues

In this contribution, we review the molecular and physiological barriers to oral delivery of peptides and nanoparticles. We discuss the opportunities and predictivity of various in vitro systems with special emphasis on human intestine in Ussing chambers. First, the molecular constraints to peptide absorption are discussed. Then the physiological barriers to peptide delivery are examined. These include the gastric and intestinal environment, the mucus barrier, tight junctions between epithelial cells, the enterocytes of the intestinal epithelium, and the subepithelial tissue. Recent data from human proteome studies are used to provide information about the protein expression profiles of the different physiological barriers to peptide and nanoparticle absorption. Strategies that have been employed to increase peptide absorption across each of the barriers are discussed. Special consideration is given to attempts at utilizing endogenous transcytotic pathways. To reliably translate in vitro data on peptide or nanoparticle permeability to the in vivo situation in a human subject, the in vitro experimental system needs to realistically capture the central aspects of the mentioned barriers. Therefore, characteristics of common in vitro cell culture systems are discussed and compared to those of human intestinal tissues. Attempts to use the cell and tissue models for in vitro-in vivo extrapolation are reviewed.

Nanoparticles for oral delivery: Design, evaluation and state-of-the-art

The oral route is a preferred method of drug administration, though achieving effective drug delivery and minimizing off-target side effects is often challenging. Formulation into nanoparticles can improve drug stability in the harsh gastrointestinal (GI) tract environment, providing opportunities for targeting specific sites in the GI tract, increasing drug solubility and bioavailability, and providing sustained release in the GI tract. However, the unique and diverse physiology throughout the GI tract, including wide variation in pH, mucus that varies in thickness and structure, numerous cell types, and various physiological functions are both a barrier to effective delivery and an opportunity for nanoparticle design. Here, nanoparticle design aspects to improve delivery to particular sites in the GI tract are discussed. We then review new methods for evaluating oral nanoparticle formulations, including a short commentary on data interpretation and translation. Finally, the state-of-the-art in preclinical targeted nanoparticle design is reviewed.

Methocel-Lipid Hybrid Nanocarrier for Efficient Oral Insulin Delivery

Even with the use of double-emulsion technique for preparation, the hydrophobic nature of solid lipid nanoparticles (SLNs) limits their encapsulation efficiency (EE%) for peptides such as insulin. In this study, we hypothesize that inclusion of Methocel into SLN to form Methocel-lipid hybrid nanocarriers (MLNs) will significantly enhance insulin EE% without compromising the various characteristics of SLN favorable for oral drug delivery. Our data show that incorporation of 2% wt/wt of Methocel A15C had doubled insulin EE% (around 40%) versus conventional SLN prepared using standard double emulsion technique. MLN significantly protected the entrapped insulin against chymotrypsin degradation at gastrointestinal pH. Using intestinal epithelial cells Caco2 as a model, it was shown that MLN could be extensively taken up by Caco2 cells while demonstrating low cytotoxicity. The results indicate that MLN have preserved the key advantages of SLN (biocompatibility, low cytotoxicity, good drug protection, and good interaction with cells) while overcoming their key limitation for efficient peptide entrapment. Based on this, MLN may serve as a promising nanocarrier for oral delivery of peptides.