Formulation design and development of matrix diffusion controlled transdermal drug delivery of glimepiride

Development and evaluation of quercetin enriched bentonite-reinforced starch-gelatin based bioplastic with antimicrobial property

Nowadays novel bio-based materials have been widely employed in food and pharmaceutical industry because of their wide acceptability by the consumers rather than the synthetic materials nevertheless, they possess poor mechanical properties. Reinforcement of biopolymers with intercalation of mineral clays can improve their physicochemical properties; so that such biocomposites possess superior barrier and mechanical properties as well as stability and drug loading efficacy. Thus, this research aimed at formulating quercetin loaded bentonite-reinforced starch-gelatin based novel bioplastic with diverse applicability. The methodology of the study included Box Behnken optimization as well as physical, structural, mechanical and antimicrobial properties evaluation of the proposed reinforced bioplastics. Amount of starch, bentonite and glycerin were the independent variables while the tensile strength, swelling index and elongation percentage were studied as dependent variables. The optimized bioplastic film showed excellent physicochemical and morphological characteristics and also for efficient percentage drug content. The antimicrobial activity showed the highest activity against Escherichia coli followed by Pseudomonas aeruginosa and Staphylococcus aureus. Scanning electron microscopy (SEM) revealed the non-homogenous nature of the film. Generally, the results revealed that quercetin loaded bentonite-reinforced starch-gelatin based could be used as ecological friendly active food packaging as well as pharmaceutical application with significant antimicrobial properties.

Innovative Topical Patches for Non-Melanoma Skin Cancer: Current Challenges and Key Formulation Considerations

Non-melanoma skin cancer (NMSC) is the most prevalent malignancy worldwide, with approximately 6.3 million new cases worldwide in 2019. One of the key management strategies for NMSC is a topical treatment usually utilised for localised and early-stage disease owing to its non-invasive nature. However, the efficacy of topical agents is often hindered by poor drug penetration and patient adherence. Therefore, various research groups have employed advanced drug delivery systems, including topical patches to overcome the problem of conventional topical treatments. This review begins with an overview of NMSC as well as the current landscape of topical treatments for NMSC, specifically focusing on the emerging technology of topical patches. A detailed discussion of their potential to overcome the limitations of existing therapies will then follow. Most importantly, to the best of our knowledge, this work unprecedentedly combines and discusses all the current advancements in innovative topical patches for the treatment of NMSC. In addition to this, the authors present our insights into the key considerations and emerging trends in the construction of these advanced topical patches. This review is meant for researchers and clinicians to consider utilising advanced topical patch systems in research and clinical trials toward localised interventions of NMSC.

Atorvastatin liposomes in a 3D-printed polymer film: a repurposing approach for local treatment of oral candidiasis

Oral candidiasis (OC) is an opportunistic fungal infection, common amongst the elderly and the immunocompromised. Unfortunately, the therapeutic efficacy of common antifungals is imperiled by the rise of antifungal drug resistance. An alternative promising therapeutic option possibly contributing to antifungal therapy is drug repurposing. Herein, we aimed to employ novel pharmaceutical drug delivery for enhancing the emerging antifungal potential of the hypocholesterolemic drug atorvastatin (ATV). ATV-propylene-glycol-liposomes (ATV/PG-Lip) were prepared then integrated in 3D-printed (3DP) mucoadhesive films comprising chitosan, polyvinyl-alcohol and hydroxypropyl methylcellulose, as an innovative blend, for the management of OC. ATV/PG-Lip demonstrated good colloidal properties of particle size (223.3 ± 2.1 nm), PDI (0.12 ± 0.001) and zeta potential (-18.2 ± 0.3 mV) with high entrapment efficiency (81.15 ± 1.88%) and sustained drug release. Also, ATV/PG-Lip showed acceptable three-month colloidal stability and in vitro cytocompatibility on human gingival fibroblasts. The developed 3DP-films exhibited controlled ATV release (79.4 ± 1.4% over 24 h), reasonable swelling and mucoadhesion (2388.4 ± 18.4 dyne/cm2). In vitro antifungal activity of ATV/PG-Lip was confirmed against fluconazole-resistant Candida albicans via minimum inhibitory concentration determination, time-dependent antifungal activity, agar diffusion and scanning electron microscopy. Further, ATV/PG-Lip@3DP-film exceeded ATV@3DP-film in amelioration of infection and associated inflammation in an in vivo oral candidiasis rabbit model. Accordingly, the results confirm the superiority of the fabricated ATV/PG-Lip@3DP-film for the management of oral candidiasis and tackling antifungal resistance.

Transport of hydrocortisone in targeted layers of the skin by multi-lamellar liposomes

Hydrocortisone (HyC), a hydrophobic pharmaceutical active, was encapsulated in multi-lamellar liposomes (MLLs) composed of P100, a mixture of phospholipids, and Tween®80. Three different HyC-loaded formulations were designed to target the stratum corneum, the living epidermis and the hypodermis. The impact of encapsulation on their size, elasticity and zeta potential, the three key factors controlling MLLs skin penetration, was studied. Raman mapping of phospholipids and HyC allowed the localisation of both components inside an artificial skin, Strat-M®, demonstrating the efficiency of the targeting. Percutaneous permeation profiles through excised human skin were performed over 48 h, supporting results on artificial skin. Their modelling revealed that HyC encapsulated in MLLs, designed to target the stratum corneum and living epidermis, exhibited a non-Fickian diffusion process. In contrast, a Fickian diffusion was found for HyC administered in solution, in a pharmaceutical cream and in transdermal MLLs. These results allowed us to propose a mechanism of interaction between HyC-containing MLLs and the skin.

A comprehensive review on invasomal carriers incorporating natural terpenes for augmented transdermal delivery

Background

Transdermal drug delivery is one of the most widely used drug administration routes, which offer several advantages over other routes of drug delivery. The apical layer of the skin called the stratum corneum is the most dominant obstacle in the transdermal drug delivery, which restricts the passage of drugs across the skin. Considerable strategies have been applied to enhance the rate of permeation across the epithelial cells; however, the most widely used strategy is the use of sorption boosters, also known as permeation enhancers.

Main body

Terpenes were considered as efficient skin permeation enhancers and are generally recognized as safe as per Food and Drug Administration. Terpenes improve the permeability of drugs either by destructing the stratum corneum’s tightly packed lipid framework, excessive diffusivity of drug in cell membrane or by rampant drug partitioning into epithelial cells. Various vesicular systems have been developed and utilized for the transdermal delivery of many drugs. Invasomes are one such novel vesicular system developed which are composed of phospholipids, ethanol and terpenes. The combined presence of ethanol and terpenes provides exceptional flexibility to the vesicles and improves the permeation across the barrier offered due to the stratum corneum as both ethanol and terpenes act as permeation enhancers. Therefore, utilization of invasomes as carriers to facilitate higher rate of drug permeation through the skin can be a very useful approach to improve transdermal drug delivery of a drug.

Conclusion

The paper focuses on a broad updated view of terpenes as effective permeation enhancers and invasomes along with their applications in the pharmaceutical formulations.

Microscopic and Spectroscopic Imaging and Thermal Analysis of Acrylates, Silicones and Active Pharmaceutical Ingredients in Adhesive Transdermal Patches

Dermal or transdermal patches are increasingly becoming a noteworthy alternative as carriers for active pharmaceutical ingredients (APIs), which makes their detailed physicochemical evaluation essential for pharmaceutical development. This paper demonstrates mid-infrared (FTIR) and Raman spectroscopy with complementary microscopic methods (SEM, optical and confocal Raman microscopy) and differential scanning calorimetry (DSC) as tools for the identification of the state of model API (testosterone TST, cytisine CYT or indomethacin IND) in selected adhesive matrices. Among the employed spectroscopic techniques, FTIR and Raman may be used not only as standard methods for API identification in the matrix, but also as a means of distinguishing commercially available polymeric materials of a similar chemical structures. A novel approach for the preparation of adhesive polymers for the FTIR analysis was introduced. In silicone matrices, all three APIs were suspended, whereas in the case of the acrylic PSA, Raman microscopy confirmed that only IND was dissolved in all three acrylic matrices, and the dissolved fraction of the CYT differed depending on the matrix type. Moreover, the recrystallization of TST was observed in one of the acrylates. Interestingly, a DSC analysis of the acrylic patches did not confirm the presence of the API even if the microscopic images showed suspended particles.

An Integrative QbD Approach for the Development and Optimization of Controlled Release Compressed Coated Formulation of Water-Soluble Drugs

Controlled release dosage forms maintain regulated pharmacokinetic profile of drug substance within its therapeutic window by ensuring constant plasma concentrations. Controlled release formulations not only increase the therapeutic efficacy of drug substances but also reduce their dose-related side effects. Present investigation was conducted to develop, optimize, and validate compressed coated controlled release tablet formulation for highly water-soluble drug substances which have no rate-controlling factor towards its release from dosage form. Drug dispersed waxy core tablet, press coated within the swellable hydrophilic polymeric barrier layer, was developed and optimized via quality by design approach (QbD) using Box-Behnken design. The optimized formulation was characterized and validated using in vitro quality control parameters. Attributes identified under SUPAC guidelines, such as drug release rates at 30 min, 6 h, and 12 h, were considered as the critical quality attributes (CQAs) that significantly affected efficiency of the compressed coated controlled release tablets. CQAs screened using risk assessment and Pareto chart analyses were used for optimizing controlled release dosage form. Findings revealed that tablets containing drug to wax ratio of 1:1, hydrophilic swellable polymer concentration of 200 mg, and prepared using compression pressure of 6.5 kg/cm² exhibited the highest desirability indices in terms of controlling the release rate of drug substance. Optimized formulation was also evaluated for swelling rate, erosion rate, and other post-compression parameters, including release kinetics. Fickian diffusion-based zero-order controlled release of BCS class I drug substance was achieved through the developed dosage form.

Systematic Review on the Effectiveness of Essential and Carrier Oils as Skin Penetration Enhancers in Pharmaceutical Formulations

Oils, including essential oils and their constituents, are widely reported to have penetration enhancement activity and have been incorporated into a wide range of pharmaceutical formulations. This study sought to determine if there is an evidence base for the selection of appropriate oils for particular applications and compare their effectiveness across different formulation types. A systematic review of the data sources, consisting of Google Scholar, EMBASE, PubMed, Medline, and Scopus, was carried out and, following screening and quality assessment, 112 articles were included within the analysis. The research was classified according to the active pharmaceutical ingredient, dosage form, in vitro/in vivo study, carrier material(s), penetration enhancers as essential oils, and other chemical enhancers. The review identified four groups of oils used in the formulation of skin preparations; in order of popularity, these are terpene-type essential oils (63%), fatty acid-containing essential oils (29%) and, finally, 8% of essential oils comprising Vitamin E derivatives and miscellaneous essential oils. It was concluded that terpene essential oils may have benefits over the fatty acid-containing oils, and their incorporation into advanced pharmaceutical formulations such as nanoemulsions, microemulsions, vesicular systems, and transdermal patches makes them an attractive proposition to enhance drug permeation through the skin.

Fabrication of Tizanidine Loaded Patches Using Flaxseed Oil and Coriander Oil as a Penetration Enhancer for Transdermal Delivery

Transdermal drug delivery is important to maintain plasma drug concentrations for therapeutic efficacy. The current study reports the design, formulation, and evaluation of tizanidine transdermal patches formulated using chitosan and thiolated chitosan, ethyl cellulose (EC), polyvinylpyrrolidone (PVP), and Eudragit RL100 in different ratios. The tizanidine patches were formulated using flaxseed oil and coriander oil in the concentrations of 1% v/w, 2% v/w, 3% v/w, 4% v/w, 5% v/w, and 10% v/w. The patches were subjected to characterization of physicochemical property (thickness, weight uniformity, drug content, efficiency, percentage moisture uptake/loss), in vitro drug release and drug permeation, skin irritation, in vivo application, pharmacokinetics analysis, and stability studies. The results indicate that the interaction of thiolated chitosan with the negative charges of the skin opens the tight junctions of the skin, whereas flaxseed and coriander oils change the conformational domain of the skin. The novelty of this study is in the use of flaxseed and coriander oils as skin permeation enhancers for the formulation of tizanidine transdermal patches. The formulations follow non-Fickian drug release kinetics. The FTZNE23, FTZNE36 and FTZNE54, with 5% v/w flaxseed oil loaded formulations, exhibited higher flux through rabbit skin compared with FTZNE30, FTZNE35, FTZNE42, and FTZNE47, formulations loaded with 10% v/w coriander oil. The study concludes that flaxseed oil is a better choice for formulating tizanidine patches, offering optimal plasma concentration and therapeutic efficacy, and recommends the use of flaxseed and coriander oil based patches as a novel transdermal delivery system for tizanidine and related classes of drugs.

Recent advances in polymeric transdermal drug delivery systems

Transdermal delivery has proven to be one of the most favorable methods among novel drug delivery systems. Since drugs administered by transdermal delivery systems avoid the gastrointestinal tract, and thus avoid conversion by the liver, the likelihood of liver dysfunction and gastrointestinal tract irritation as side effects is low. Drug delivery through the skin has other advantages, such as maintaining an effective rate of drug delivery over time, a steady rate of circulation, and the benefits of a passive delivery system and diffusion. Transdermal drug delivery is achieved using patches which consist of different and specific layers. In the last few decades, many types of patches have been approved worldwide, such as medical plasters, which have been generally applied to the skin for localized diseases. Such patches can be traced back to ancient China (around 2000 BCE) and are the early precursors of today's transdermal patches. With the help of effective design, materials, manufacturing, and evaluation, a large number of drugs can now be administered using this valuable advanced technology. This study reviews different types of polymer patches, their advantages and disadvantages, and different studies related to transdermal drug delivery methods, and the advantages and disadvantages of each method. Different mechanisms of transdermal drug delivery system with patches are also discussed.

Effect of a Selection of Skin Penetration Enhancers on Topical Anti-Inflammatory Effect of Boswellic Acids in Carrageenan-Induced Paw Edema in Rats

BACKGROUND

Boswellia species have been used for treatment of chronic inflammatory disease. Several studies have documented the anti-inflammatory effect of Boswellic acids (BAs) after systemic administration. This study was aimed to evaluate the effect of some skin penetration enhancers on topical anti-inflammatory effect of BAs in rats.

MATERIALS AND METHODS

Male Wistar rats weighting 180-220 were used. Anti-inflammatory activity was assessed using carrageenan test. BAs dissolved in ethanol, propylene glycol 2%, 5%, olive oil and applied topically. Menthol, D-limonene, or eucalyptus oil 0.5%, 1% were also tested as other skin penetration enhancers and applied topically 30 min prior to subplantar injection of carrageenan into the right hind paw of rats. The volume of the paw was measured at 0 and 4 h after carrageenan with a digital plethysmometer and the difference was used as an index of inflammation. Piroxicam gel was used as a standard drug.

RESULTS

A 4% ethanolic solution of BAs showed significant anti-inflammatory effect. Propylene glycol (2% and 5%) in alcohol did not change the effect. Olive oil also enhanced penetration of BAs. Menthol 0.5%, 1% and D-limonene 0.5%, 1% did not show any significant change compared to olive oil alone. In the present study, eucalyptus oil 1% in olive oil was known as the best carrier for transdermal delivery of BAs.

CONCLUSION

BAs have considerable topical anti-inflammatory effects and olive oil alone or especially in combination with eucalyptus oil can be promising vehicles for skin penetration of topical BAs.

The Optimization of a Dimenhydrinate Transdermal Patch Formulation Based on the Quantitative Analysis of In Vitro Release Data by DDSolver through Skin Penetration Studies

Dimenhydrinate is an over-the-counter medication that is used to relieve nausea, vomiting, and vertigo caused by motion sickness. It has a short elimination half-life, possibly due to its first-pass metabolism. The current study aimed to prepare and evaluate new transdermal formulations of dimenhydrinate to prolong the drug’s release and improve its cutaneous permeation. First, the patches were fabricated and evaluated to determine their properties. The results were statistically investigated and considered significant at the p < 0.05 level. Additionally, the quantitative analysis of the drug-release data and kinetic modeling was performed by using the DDSolver software to decide the candidate formula dependably. The effect of the penetration enhancers on the permeability of dimenhydrinate from the selected patch was then studied ex vivo compared to the control sample, and the patch’s safety was evaluated in rabbits, using the skin-irritation test.

Can limonene be a possible candidate for evaluation as an agent or adjuvant against infection, immunity, and inflammation in COVID-19?

Coronavirus disease (COVID-19) caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an ongoing pandemic and presents a public health emergency. It has affected millions of people and continues to affect more, despite the tremendous social preventive measures. The therapeutic strategy relies on suppressing infectivity and inflammation, along with immune modulation. The identification of candidate drugs effective for COVID-19 is crucial, thus many natural products including phytochemicals are also being proposed for repurposing and evaluated for their potential in COVID-19. Among numerous phytochemicals, limonene (LMN), a dietary terpene of natural origin has been recently showed to target viral proteins in the in-silico studies. LMN is one of the main compounds identified in many citrus plants, available and accessible in diets and well-studied for its therapeutic benefits. Due to dietary nature, relative safety and efficacy along with favorable physicochemical properties, LMN has been suggested to be a fascinating candidate for further investigation in COVID-19. LMN showed to modulate numerous signaling pathways and inhibits inflammatory mediators, including cytokines, chemokines, adhesion molecules, prostanoids, and eicosanoids. We hypothesized that given the pathogenesis of COVID-19 involving infection, inflammation, and immunity, LMN may have potential to limit the severity and progression of the disease owing to its immunomodulatory, anti-inflammatory, and antiviral properties. The present article discusses the possibilities of LMN in SARS-CoV-2 infections based on its immunomodulatory, anti-inflammatory, and antiviral properties. Though, the suggestion on the possible use of LMN in COVID-19 remains inconclusive until the in-silico effects confirmed in the experimental studies and further proof of the concept studies. The candidature of LMN in COVID-19 treatment somewhat appear speculative but cannot be overlooked provided favorable physiochemical and druggable properties. The safety and efficacy of LMN are necessary to be established in preclinical and clinical studies before making suggestions for use in humans.

Ocular films versus film-forming liquid systems for enhanced ocular drug delivery

The short residence time, corneal barrier functions, and other effective eye protective mechanisms limited the ocular availability after topical application. Ocular inserts are being developed as polymer films for insertion into the conjunctival sac with the goal of increasing ocular availability. Unfortunately, these devices are not convenient for patients and are associated with many problems. The use of in situ gel/film-forming systems may provide promising alternative with comparable efficacy but this requires verification. Therefore, the current study compared ocular inserts with in situ film-forming liquids containing the same polymer components for ocular delivery of pilocarpine nitrate. Solvent casting technique was employed to prepare the inserts using and polyvinyl alcohol (PVA) as film-forming polymer blended with sodium alginate, as bioadhesive polymer. The effect of addition of either carboxymethycellulose, carbopol, polyvinylpyrrolidone, or methylcellulose was investigated. Solid-state characterization of the inserts indicated compatibility of the drug with film component. All inserts were of acceptable bioadhesive parameters and folding endurance that depended on the film composition. In vitro release studies reflected matrix diffusion kinetics for the film and liquid formulations. This confirms the in situ gelation of liquids. The calculated in vivo miotic pharmacokinetics parameters, using albino rabbits, reflected a better rank for the film but the difference was not statistically different from the in situ gel/film-forming systems. Ocular safety, as reflected by tear volume test, indicated acceptable safety of both liquid and inserts to the eye. The study suggested comparable efficacy of film-forming liquids to that of ocular films. Graphical abstract.

Role of sodium l-cysteine alginate conjugate and isopropyl myristate to enhance the permeation enhancing activity of BCS class III drug from TDDS; optimization by central composite design and in vivo pharmacokinetics study

OBJECTIVE

The objective of the present research was to study the effect and optimization of sodium alginate l-cysteine conjugate and permeation enhancer on permeation of high soluble low permeable ropinirole hydrochloride from the transdermal formulation.

METHODS

Sodium alginate l-cysteine conjugate was prepared and characterized and the same was added into a transdermal formulation along with IPM as a permeation enhancer. Twelve primary formulations were prepared by solvent casting method and evaluated. The results were fed into Design Expert® Software to obtain optimized formulation. The optimized formulation was evaluated for physicochemical, ex vivo permeation, stability, skin irritation, and pharmacokinetic studies.

RESULTS

The results of the characterization of prepared sodium alginate l-cysteine conjugate confirmed the thiolation process. Stability studies suggested that the drug was compatible with all the excipients. SEM images of the transdermal patch revealed that the amorphous drug was uniformly distributed. From the design space, the optimized formulation from the polymer's ratio (SA: SACC; 4:6) and IPM 9.5%w/w of polymers weight showed target steady state flux 9.004 µg/cm²/h with maximum drug permeation. The increased target flux and maximum drug permeation from an optimized patch suggested that there was an effect of SACC on ropinirole hydrochloride permeation in the presence of IPM as a permeation enhancer. Pharmacokinetic studies in rabbits showed that the optimized patch improved bioavailability as compared to marketed oral tablets.

CONCLUSIONS

The study was concluded that there was a positive effect of sodium alginate l-cysteine conjugate and IPM on ropinirole hydrochloride permeation from the transdermal formulation.

O/W Nanoemulsion as an Adjuvant for an Inactivated H3N2 Influenza Vaccine: Based on Particle Properties and Mode of Carrying

Background and Purpose

Adjuvant can reduce vaccine dosage and acquire better immune protection to the body, which helps to deal with the frequent outbreaks of influenza. Nanoemulsion adjuvants have been proved efficient, but the relationship between their key properties and the controlled release which greatly affects immune response is still unclear. The present work explores the role of factors such as particle size, the polydispersity index (PDI), stability and the safety of nanoemulsions by optimizing the water concentration, oil phase and modes of carrying, to explain the impact of those key factors above on adjuvant effect.

Methods

Isopropyl myristate (IPM), white oil, soybean oil, and grape-kernel oil were chosen as the oil phase to explore their roles in emulsion characteristics and the adjuvant effect. ICR mice were immunized with an emulsion-inactivated H3N2 split influenza vaccine mixture, to compare the nanoemulsion’s adjuvant with traditional aluminium hydroxide or complete Freund’s adjuvant.

Results

Particle size of all the nanoemulsion formed in our experiment ranged from 20 nm to 200 nm and did not change much when diluted with water, while the PDI decreased obviously, indicating that the particles tended to become more dispersive. Formulas with 80% or 85.6% water concentration showed significant higher HAI titer than aluminium hydroxide or complete Freund’s adjuvant, and adsorption rather than capsule mode showed higher antigen delivery efficiency. As mentioned about oil phase, G (IPM), F (white oil), H (soybean oil), and I (grape-kernel oil) showed a decreasing trend in their adjuvant efficiency, and nanoemulsion G was the best adjuvant with smaller and uniform particle size.

Conclusion

Emulsions with a smaller, uniform particle size had a better adjuvant effect, and the adsorption mode was generally more efficient than the capsule mode. The potential adjuvant order of the different oils was as follows: IPM > white oil > soybean oil > grape-kernel oil.