Exploring temozolomide encapsulated PEGylated liposomes and lyotropic liquid crystals for effective treatment of glioblastoma: in-vitro, cell line, and pharmacokinetic studies

Temozolomide (TMZ) is one of the best choices for treating glioblastoma. However, due to the short plasma half-life, only 20-30 % brain bioavailability can be achieved using traditional formulations. In the present study, PEGylated liposomes and lyotropic liquid crystals (LLCs) were developed and investigated to prolong the plasma circulation time of TMZ. Industrially feasible membrane extrusion and modified hot melt emulsification techniques were utilized during the formulation. Liposomes and LLCs in the particle size range of 80-120 nm were obtained with up to 50 % entrapment efficiency. The nanocarriers were found to show a prolonged release of up to 72 h. The cytotoxicity studies in glioblastoma cell lines revealed a ∼1.6-fold increased cytotoxicity compared to free TMZ. PEGylated liposomes and PEGylated LLCs were found to show a 3.47 and 3.18-fold less cell uptake in macrophage cell lines than uncoated liposomes and LLCs, respectively. A 1.25 and 2-fold increase in the plasma t1/2 was observed with PEGylated liposomes and PEGylated LLCs, respectively, compared to the TMZ when administered intravenously. Extending plasma circulation time of TMZ led to significant increase in brain bioavailability. Overall, the observed improved pharmacokinetics and biodistribution of TMZ revealed the potential of these PEGylated nanocarriers in the efficient treatment of glioblastoma.

Tailoring the multi-functional properties of phospholipids for simple to complex self-assemblies

The unique interfacial properties, huge diversity, and biocompatible nature of phospholipids make them an attractive pharmaceutical excipient. The amphiphilic nature of these molecules offers them the property to self-assemble into distinct structures. The solubility, chemical and structural properties, surface charge, and critical packing parameters of phospholipids play an essential role during formulation design. This review focuses on the relationship between the structural features of a phospholipid molecule and the formation of different lipid-based nanocarrier drug delivery systems. This provides a rationale and guideline for the selection of appropriate phospholipids while designing a drug delivery system. Finally, we refer to relevant recent case studies covering different types of phospholipid-based systems including simple to complex assemblies. Different carriers in the size range of 50 nm to a few microns can be prepared using phospholipids. The carriers can be delivered through oral, intravenous, nasal, dermal, transmucosal, and subcutaneous routes. A wide range of applicability can be achieved by incorporating various hydrophilic and lipophilic additives in the phospholipid bilayer. Advanced research has led to the discovery of phospholipid complexes and cell membrane mimicking lipids. Overall, phospholipids remain a versatile pharmaceutical excipient for drug delivery. They play multiple roles as solubilizer, emulsifier, surfactant, permeation enhancer, coating agent, release modifier, and liposome former.

Emerging trends in microneedle-based drug delivery strategies for the treatment of rheumatoid arthritis

INTRODUCTION

The current drug therapies for treating Rheumatoid Arthritis (RA) include NSAIDs, DMARDs, or biological products designed to mitigate the symptoms of the disease. These therapies with conventional delivery systems possess limitations such as lack of selectivity and adverse effects in the extra-articular tissues. Microneedles-based transdermal drug delivery gained huge attention that can overcome the limitations associated with conventional preparations.

AREAS COVERED

This review aims to provide detailed information on types of Microneedles (MNs) and their usage in drug delivery for the management of Rheumatoid Arthritis. In addition, it also provides evidence for the effective use of MNs in RA treatment. Various types of MNs, their regulatory status, clinical trials and patents are also compiled in this review.

EXPERT OPINION

Microneedles are small patch-like structures consisting of needles in micron range arranged in array-like structure, used to manage drugs designed to be given via transdermal route. Microneedles provide painless delivery, fast onset of action, bypass the first-pass metabolism and be easily self-administered. In the case of RA treatment, which requires a long-term application of drugs, MNs is a new and emerging way to ease the symptoms of RA.

Revisiting techniques to evaluate drug permeation through skin

INTRODUCTION

Investigating the transportation of a drug molecule through various layers of skin and determining the amount of drug retention in skin layers is of prime importance in transdermal and topical drug delivery. The information regarding drug permeation and retention in skin layers aids in optimizing a formulation and provides insight into the therapeutic efficacy of a formulation.

AREAS COVERED

This perspective covers various methods that have been explored to estimate drug/therapeutics in skin layers using in vitro, ex vivo, and in vivo conditions. In vitro methods such as diffusion techniques, ex vivo methods such as isolated perfused skin models and in vivo techniques including dermato-pharmacokinetics employing tape stripping, and microdialysis are discussed. Application of all techniques at various stages of formulation development where various local and systemic effects need to be considered.

EXPERT OPINION

The void in the existing methodologies necessitates improvement in the field of dermatologic research. Standardization of protocols, experimental setups, regulatory guidelines, and further research provides information to select an alternative for human skin to perform skin permeation experiments to increase the reliability of data generated through the available techniques. There is a need to utilize multiple techniques for appropriate dermato-pharmacokinetics evaluation and formulation's efficacy.

UV spectroscopic method for estimation of temozolomide: Application in stability studies in simulated plasma pH, degradation rate kinetics, formulation design, and selection of dissolution media

Temozolomide (TMZ) is a broad spectrum alkylating agent found effective in the treatment of glioblastoma multiforme, refractory anaplastic astrocytoma, and metastatic melanoma. The major drawback associated with TMZ is pH-dependent stability and short half-life. At physiological pH, it undergoes conversion to MTIC (methyltriazine imidazole carboxamide) and AIC (amino imidazole carboxamide), resulting in only 20-30% brain bioavailability. There is a need for an analytical method for the estimation of TMZ in stability samples and nanoformulations. In this research study, analytical methods were developed for the estimation of TMZ using two media pH 1.2 (0.1 N HCl) and pH 4.5 acetate buffer, which were validated for linearity, range, precision, accuracy, limit of detection, limit of quantification, and specificity as per ICH guidelines. The % RSD was found to be <2% indicating the reliability of the method. Further, the application of the developed methods was explored. The stability of TMZ in three pH conditions (1.2, 4.5, and 7.4) and the respective degradation rate kinetics was studied. Conversion of TMZ was found to follow first order kinetics with the conversion rate of 0.0011, 0.0011, and 0.0453 h^-1 in pH 1.2, 4.5, and 7.4 respectively. The developed methods accurately estimated the TMZ concentration in lipid nanoformulation (liposomes) indicated by ~100% recovery. Acetate buffer (pH 4.5) was found to be an appropriate dissolution media for TMZ loaded lipid nanoformulations. The developed methods were found to be suitable for routine analysis, for the determination of drug stability and estimation of temozolomide in lipid nanoformulations.

Quality by design (QbD) in the formulation and optimization of liquid crystalline nanoparticles (LCNPs): A risk based industrial approach

The intersection of lipid-based nanoparticles and lyotropic liquid crystals has provided a novel type of nanocarrier system known as 'lipid-based lyotropic liquid crystals' or 'liquid crystalline nanoparticles' (LCNPs). The unique advantages and immense popularity of LCNPs can be exploited in a better way if the formulation of LCNPs is done using the approach of quality by design (QbD). QbD is a systematic method that can be utilized in formulation development. When QbD is applied to LCNPs formulation, it will proffer many unique advantages, such as better product and process understanding, the flexibility of process within the design space, implementation of more effective and efficient control strategies, easy transfer from bench to bedside, and more robust product. In this work, the application of QbD in the formulation of LCNPs has been explored. The elements of QbD, viz. quality target product profile, critical quality attributes, critical material attributes, critical process parameters, quality risk management, design of experiments, and control strategy for the development of LCNPs have been explained in-depth with case studies. The present work will help the reader to understand the nitty-gritties in the application of QbD in the formulation of LCNPs, and provide a base for QbD-driven formulation of LCNPs with a regulatory perspective.

Biodegradable microneedles fabricated with carbohydrates and proteins: Revolutionary approach for transdermal drug delivery

There has been a surge in the use of transdermal drug delivery systems (TDDS) for the past few years. The market of TDDS is expected to reach USD 7.1 billion by 2023, from USD 5.7 billion in 2018, at a CAGR of 4.5%. Microneedles (MNs) are a novel class of TDDS with advantages of reduced pain, low infection risk, ease of application, controlled release of therapeutic agents, and enhanced bioavailability. Biodegradable MNs fabricated from natural polymers have become the center of attention among formulation scientists because of their recognized biodegradability, biocompatibility, ease of fabrication, and sustainable character. In this review, we summarize the various polysaccharides and polypeptide based biomaterials that are used to fabricate biodegradable MNs. Particular emphasis is given to cellulose and its derivatives, starch, and complex carbohydrate polymers such as alginates, chitosan, chondroitin sulfate, xanthan gum, pullulan, and hyaluronic acid. Additionally, novel protein-based polymers such as zein, collagen, gelatin, fish scale and silk fibroin (polyamino acid) biopolymers application in transdermal drug delivery have also been discussed. The current review will provide a unique perspective to the readers on the developments of biodegradable MNs composed of carbohydrates and protein polymers with their clinical applications and patent status.

Luliconazole loaded lyotropic liquid crystalline nanoparticles for topical delivery: QbD driven optimization, in-vitro characterization and dermatokinetic assessment

Fungal infections are an important cause of morbidity and pose a serious health concern especially in immunocompromised patients. Luliconazole (LUL) is a topical imidazole antifungal drug with a broad spectrum of activity. To overcome the limitations of conventional dosage forms, LUL loaded lyotropic liquid crystalline nanoparticles (LCNP) were formulated and characterized using a three-factor, five-level Central Composite Design of Response Surface Methodology. LUL loaded LCNP showed particle size of 181 ± 12.3 nm with an entrapment efficiency of 91.49 ± 1.61 %. The LUL-LCNP dispersion in-vitro drug release showed extended release up to 54 h. Ex-vivo skin permeation studies revealed transdermal flux value (J) of LUL-LCNP gel (7.582 μg/h/cm²) 2 folds higher compared to marketed cream (3.3706 μg/h/cm²). The retention of LUL in the stratum corneum was ∼1.5 folds higher and ∼2 folds higher in the epidermis and other deeper layers in comparison to the marketed cream. The total amount of drug penetrated (AUC_0-∞) with LCNP formulation was 4.7 folds higher in epidermis and 6.5 folds higher in dermis than marketed cream. The study's findings vouch that LCNP can be a promising and effective carrier system for the delivery of antifungal drugs with enhanced skin permeation.

Nanostructured Lipid Carriers as Potential Drug Delivery Systems for Skin Disorders

Background:

Skin diseases affect all the age groups of people and have an impact on patients’ physical, mental, and emotional status. Conventional topical preparation is limited with its efficacy due to low permeation, frequent application, and poor adherence to the therapy for prolong time.

Objective:

The objective of this review article is to address the emerging trends of nanotechnology derived lipidic carrier systems for an effective treatment for skin disorders.

Methodology:

Various research and review articles from reputed international journals were referred and compiled.

Results and Discussion:

opical drug delivery systems were found to be more effective than oral and parenteral drug delivery systems for treating skin diseases due to targeted localized applications with reduced side effects. Lipid-based nanoparticles have been found to have the potential in treating skin diseases due to the biocompatibility and the versatility of the lipids. Nanostructured lipid carriers (NLCs) have gained much attention in treating skin diseases due to improved stability of the drugs, enhanced skin permeation, retention, and better therapeutic efficacy. The review summarizes the NLCs characteristics and their application for topical delivery of various therapeutics in skin disorders. NLCs have shown great potential in effective drug delivery for the treatment of psoriasis, dermatitis, bacterial infections, and skin cancer. Its cosmetic application has opened a new area for skincare. Furthermore, safety and clinical status revealed its future commercial acceptability.

Conclusion:

NLCs have been found as effective lipid nanocarriers for the delivery of topical therapeutics.

Emerging Trends in Topical Delivery of Curcumin Through Lipid Nanocarriers: Effectiveness in Skin Disorders

Curcumin is a unique molecule naturally obtained from rhizomes of Curcuma longa. Curcumin has been reported to act on diverse molecular targets like receptors, enzymes, and co-factors; regulate different cellular signaling pathways; and modulate gene expression. It suppresses expression of main inflammatory mediators like interleukins, tumor necrosis factor, and nuclear factor κB which are involved in the regulation of genes causing inflammation in most skin disorders. The topical delivery of curcumin seems to be more advantageous in providing a localized effect in skin diseases. However, its low aqueous solubility, poor skin permeation, and degradation hinder its application for commercial use despite its enormous potential. Lipid-based nanocarrier systems including liposomes, niosomes, solid lipid nanoparticles, nanostructured lipid carriers, lyotropic liquid crystal nanoparticles, lipospheres, and lipid nanocapsules have found potential as carriers to overcome the issues associated with conventional topical dosage forms. Nano-size, lipophilic nature, viscoelastic properties, and occlusive effect of lipid nanocarriers provide high drug loading, hydration of skin, stability, enhanced permeation through the stratum corneum, and slow release of curcumin in the targeted skin layers. This review particularly focuses on the application of lipid nanocarriers for the topical delivery of curcumin in the treatment of various skin diseases. Furthermore, preclinical studies and patents have also indicated the emerging commercialization potential of curcumin-loaded lipid nanocarriers for effective drug delivery in skin disorders. Graphical Abstract.

Psoriasis: pathological mechanisms, current pharmacological therapies, and emerging drug delivery systems

Psoriasis is a chronic autoimmune skin disorder triggered by either genetic factors, environmental factors, life style, or a combination thereof. Clinical investigations have identified pathogenesis, such as T cell and cytokine-mediated, genetic disposition, antimicrobial peptides, lipocalin-2, galectin-3, vaspin, fractalkine, and human neutrophil peptides in the progression of psoriasis. In addition to traditional therapies, newer therapeutics, including phosphodiesterase type 4 (PDE4) inhibitors, Janus kinase (JAK) inhibitors, monoclonal antibodies (mAbs), gene therapy, anti-T cell therapy, and phytoconstituents have been explored. In this review, we highlight nanotechnology-related developments for psoriasis treatment, including patented delivery systems and therapeutics currently in clinical trials.

Insightful exploring of microRNAs in psoriasis and its targeted topical delivery

Psoriasis is a common immune-mediated inflammatory skin disease. It includes multifaceted interaction between the immune system and the keratinocytes. Recent studies depicted the role of microRNAs (miRNAs) in hyperproliferation of keratinocytes and inflammatory cytokine production, which serve as biomarkers for diagnosis, monitoring treatment response, and prognosis. miRNAs are small nucleotide sequenced noncoding RNAs. Deregulation of miRNAs was found to be the most common factor in the studies pertaining to psoriasis. Hence, miRNA-based targeting for psoriasis treatment became the primary field of current research. miRNA due to its spatial and chemical properties offer different challenges in the process of its delivery. The topical delivery of different siRNAs and genes has paved a way to similar delivery of miRNA. The topical delivery of miRNAs to the skin can bring a revolutionary change in the field of psoriasis treatment.

UV spectrophotometric method for simultaneous estimation of betamethasone valerate and tazarotene with absorption factor method: Application for in-vitro and ex-vivo characterization of lipidic nanocarriers for topical delivery

The present study elucidates the development of an accurate, precise and simple simultaneous estimation method for the routine analysis of Betamethasone Valerate (BV) and Tazarotene (TZ). This combination is widely used in the treatment of psoriasis. No method has been reported so far for the simultaneous estimation of BV and TZ in topical dosage forms. The method proposed by this study for the quantification of BV and TZ is the Absorption factor method. The developed method was validated as per the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guideline. The validated method was found to be linear in a concentration range of 10-38 μg/mL and 4-14 μg/mL for BV and TZ respectively with a regression coefficient >0.990. The method was validated for accuracy and precision which revealed the recovery of >99.80% with RSD <2.0. The method was found to be precise with RSD <2% for inter and intraday. The developed method was employed for quantification of BV and TZ in lipid based nanocarriers formulation and their in-vitro drug release samples. Further, the developed method was successfully applied for the estimation of BV and TZ in the ex-vivo skin matrix. This showed that the method can sensitively determine the drugs in aqueous and biological samples.

Design of temozolomide-loaded proliposomes and lipid crystal nanoparticles with industrial feasible approaches: comparative assessment of drug loading, entrapment efficiency, and stability at plasma pH

Temozolomide is a drug approved for treating glioblastomas, which has 100% oral bioavailability but gets degraded at physiological pH thus having very short half-life and only 20-30% brain bioavailability. Due to its amphiphilic nature, reported nanoformulations exhibits poor drug loading. The objective of this work was to formulate lipid-based drug delivery systems to enhance the brain bioavailability by prolonging the drug release and circulation time of the drug to overcome the limitations of the existing therapies and possible reduction of side effects. The size of the nanocarriers obtained was less than 300 nm and the PDI obtained was less than 0.3. The designed formulation showed higher entrapment efficiency as compared to the other reported nanocarriers of temozolomide. The designed formulations showed prolonged drug release from 12 to 20 h compared to 6 h for the pure drug. About 95% of the pure drug was degraded at plasma pH at the end of 12 h, whereas only 68% and 77% was degraded when entrapped inside the lipid crystal nanoparticles and proliposomes respectively. Further, pharmacokinetic and animal studies can confirm the potential of these for improvement of brain bioavailability.

UV Spectrophotometric method for characterization of curcumin loaded nanostructured lipid nanocarriers in simulated conditions: Method development, in-vitro and ex-vivo applications in topical delivery

Curcumin the extract obtained from the dried rhizome of turmeric, Curcuma longa is a hydrophobic phenol that delivers numerous pharmacological actions like anti-inflammatory, anti-microbial and anti-oxidant, anti-psoriasis, antidiabetic, anticancer. But curcumin has low bioavailability issues that accompany low aqueous solubility, further, when administered orally, >90% of the drug degrades rapidly in the alkaline medium. Administering the drug topically can bypass the problem as well as first-pass metabolism and therefore delivering the drug at the targeted site of action. Encapsulating curcumin in nanostructured lipid nanocarriers (NLC) is an excellent novel strategy. Further, these NLC provides both the controlled release and helps in the enhanced permeation of the drug through the skin's physiological barrier, stratum corneum. For the NLC characterization, a reliable method must be developed that can accurately and precisely determine the drug content in the formulation and also for its in-vitro and ex-vivo characterization. This experiment describes the analytical validation parameters described as per International Conference of Harmonization guidelines to develop a method using the UV-Visible spectroscopy. The method was developed in two solvent systems i.e. methanol and 6.4 pH phosphate buffer with 1.5% polysorbate 80. Methanol solvent was used for the determination of curcumin in the NLC formulation via determining the encapsulation efficiency and 6.4 pH phosphate buffer with 1.5% polysorbate 80 solvent was used for in-vitro and ex-vivo characterization of the developed NLC formulation (cream and gel). These methods were validated in response to linearity, the limit of detection, the limit of quantification, precision, accuracy, repeatability, and specificity.

Nanocarriers for ocular drug delivery: current status and translational opportunity

Ocular diseases have a significant effect on vision and quality of life. Drug delivery to ocular tissues is a challenge to formulation scientists. The major barriers to delivering drugs to the anterior and posterior segments include physiological barriers (nasolacrimal drainage, blinking), anatomical barriers (static and dynamic), efflux pumps and metabolic barriers. The static barriers comprise the different layers of the cornea, sclera, and blood–aqueous barriers whereas dynamic barriers involve conjunctival blood flow, lymphatic clearance and tear drainage. The tight junctions of the blood–retinal barrier (BRB) restrict systemically administered drugs from entering the retina. Nanocarriers have been found to be effective at overcoming the issues associated with conventional ophthalmic dosage forms. Various nanocarriers, including nanodispersion systems, nanomicelles, lipidic nanocarriers, polymeric nanoparticles, liposomes, niosomes, and dendrimers, have been investigated for improved permeation and effective targeted drug delivery to various ophthalmic sites. In this review, various nanomedicines and their application for ophthalmic delivery of therapeutics are discussed. Additionally, scale-up and clinical status are also addressed to understand the current scenario for ophthalmic drug delivery.

Ocular diseases have a significant effect on vision and quality of life.