Microsponges: a futuristic approach for oral drug delivery

Microsponges-mediated targeted topical delivery of rosemary oil for hair growth promotion: optimization and in-vivo studies

Individuals experiencing hair loss, irrespective of gender, confront significant psychological challenges. This study explores the untapped potential of rosemary oil (ROS) to stimulate hair growth, addressing its limited permeability. The focus is on innovating ROS-loaded microsponges (MS) for enhanced topical application. Utilizing Box-Behnken design (33), the study optimizes ROS-MS compositions by varying solvent volume, polymer mix, and drug concentration. The optimized ROS-MS formulation exhibits noteworthy attributes: a 94% ± 0.04 production yield, 99.6% ± 0.5 encapsulation efficiency, and 96.4% ± 1.6 cumulative ROS release within 24 h. These microsponges exhibit uniformity with a particle size of 14.1 µm ± 4.5. The OPT-ROSMS-gel showcases favorable characteristics in appearance, spreadability, pH, drug content, and extrudability. Ex-vivo skin deposition tests highlight heightened permeability of OPT-ROSMS-gel compared to pure ROS-gel, resulting in three-fold increased follicular retention. In-vivo studies underscore the superior efficacy of OPT-ROSMS-gel, revealing enhanced hair development in length, thickness, and bulb diameter, surpassing ROS-gel and minoxidil by approximately 1.2 and 1.5 times, respectively, along with nearly two-fold increase in β-catenin levels. In conclusion, microsponges emerge as a promising ROS delivery method, effectively addressing hair loss. This research advances hair loss treatments and underscores the significance of this innovative paradigm in fostering hair growth.

Obliteration of H. pylori infection through the development of a novel thyme oil laden nanoporous gastric floating microsponge

Thyme oil (TO) is a valuable essential oil believed to possess a variety of bioactivities, including antibacterial, anticancer, and antioxidant properties. These attributes grant TO the excellent capability to treat a wide range of diseases, particularly the effective eradication of Helicobacter pylori infection in the stomach. However, its practical use is limited by its low stability under atmospheric conditions. Our current research aims to encapsulate TO in eudragit (EGT) microsponges to enhance its stability and improve its effectiveness against H. pylori. The TO microsponges were prepared using EGT as a polymer, polysorbate 80 as a stabilizer, and dichloromethane (DCM) as a solvent via the quasi-emulsion solvent evaporation method. The product yield, particle size, surface morphology, entrapment efficiency, drug-polymer interaction, in-vitro floating, and in-vitro drug release of the microsponges were evaluated. The most promising microsponge was tested against H. pylori ATCC 43504 strains. The results showed that the microsponges exhibited a high product yield (ranging from 41 % ± 0.75-81.27 % ± 1.13), excellent entrapment efficiency (ranging from 63.01 % ± 0.79-88.64 % ± 0.98), prolonged in-vitro floating time (more than 12 h) and sustained in-vitro drug release for 18 h (81.53 %). Scanning electron microscopy results indicated that the microsponges were spherical in shape with a spongy surface. The average particle size of the selected microsponges was determined to be 49.79 ± 1.4 μm, and their average pore size was measured to be 0.81 ± 0.14 μm. DSC study results revealed that TO was physically entrapped in the microsponges. In-vitro anti-H. pylori activity studies demonstrated that TO in microsponge was more effective against H. pylori than pure TO. In conclusion, the developed microsponges containing thyme oil provide a promising alternative for the efficient targeting and eradication of H. Pylori infection.

Understanding the impact of formulation design on microstructure and drug release from porous microparticle-based tretinoin topical gels

For proportionally formulated intermediate strengths of a topical product, the relationship of drug release across multiple strengths of a given product is not always well understood. The current study aims to assess the proportionality of tretinoin release rates across multiple strengths of tretinoin topical gels when manufactured using two different methods to understand the impact of formulation design on drug product microstructure and tretinoin release rate. Two groups of tretinoin gels of 0.04 %, 0.06 %, 0.08 % and 0.1 % strengths were manufactured. Gels in Group I were prepared by incorporating 4-10 % g/g of 1 % w/w tretinoin-loaded microparticles into a gel base. Gels in Group II were manufactured using 10 % g/g of the microparticles that were loaded with increasing amounts (0.4-1 % w/w) of tretinoin. The two groups of gels were characterized by evaluating microstructure using a polarized microscope, rheology using an oscillatory rheometer, and drug release using Vison® Microette™ Hanson vertical diffusion cells. The microscopic images were used to discriminate between the two groups of gels based on the abundance of microparticles in the gel matrix observed in the images. This abundance increased across gels of Group I and was similar across gels of Group II. The rheology parameters, namely viscosity at a shear rate of 10 s-1, shear thinning rate, storage, and loss modulus, increased across gels of Group I, and were not significantly different across gels of Group II. The release rate of tretinoin from the drug products was proportional to the nominal strength of the drug product in both Group I and Group II, with a correlation coefficient of 0.95 in each case, although the absolute release rates differed. Overall, changing the formulation design of tretinoin topical gels containing porous microparticles may change the physicochemical and structural properties, as well as the drug release rate of the product. Further, keeping the formulation design consistent across all strengths of microparticle-based topical gels is important to achieve proportional release rates across multiple strengths of a given drug product.

Microsponges: a breakthrough tool in pharmaceutical research

Background

A microsponge delivery system (MDS) is an innovative and unique way of delivering drugs in a structured manner. Using microsponge drug delivery, regulated drug delivery may now be achieved quickly and easily.

Main body

MDS comprises porous microspheres ranging in size from 5 to 300 microns, with a large porous structure and a very tiny spherical shape. MDS is normally used to deliver drugs via topical channels, but they have recently shown the potential approach to drug delivery via oral, ophthalmic and parenteral routes. MDS can easily modify the pharmaceutical release contour and improve formulation stability while minimising the negative impact of the drug. The fundamental purpose of microsponge drug administration is to reach the highest possible peak plasma concentration in the blood. The capacity of MDS to self-sterilise is their most prominent attribute.

Conclusions

MDS is used as anti-allergic, anti-mutagenic and non-irritant in innumerable investigations. This review includes formulation, criteria for drugs to be incorporated in MDS, formulation methods, assessment parameters, and role of MDS in the management of various disorders. This review will be quite useful in the future in exploring the MDS in different disorders.

Graphical Abstract

Herbal microsponge incorporated sunscreen gel: A novel strategy

Different dermatological disorders have different effects on the lives of patients. Recently microsponge formulations have been used to treat several dermatological complications. Microsponges are basically tiny sponge like spherical particles with porous surface having valuable and attractive effect on topical delivery. The side effect of the used drug can be reduced, bioavailability can be increased, and the drug release can be modified. Microsponges can be used in different bases like gel, lotion, ointment and even in powder form. Microsponges used in sunscreen gel are now very popular. Excessive UV exposure leads to different pathological conditions like skin burns, erythema, skin carcinogenesis, etc., The microsponge sunscreen gel protects our skin from all these skin problems and most importantly, with a very less amount of side effects compared to others. Moreover, microsponges are very much cost effective, easy to handle, can deliver minimum dose of drug and enhance the stability.

Therapeutic application of microsponges based drug delivery system

Microsponges delivery system (MDS) is highly porous, cross-linked based polymeric systems, that activates in the presence of temperature, rubbing and pH. MDS offers wide range of advantage, like controlled drug release, site-specific action, stable over a broad range of pH, poor irritation, cost effective, improved patient compliance. They can be transformed into various dosage forms like creams, gels, and lotions. MDS based system are suitable for treatment of topical disorders like acne, psoriasis, dandruff, eczema, scleroderma, hair loss, skin cancer, and other dreadful diseases. MDS application for drug delivery is not limited to topical drug delivery but also explored for oral, parenteral and pulmonary drug delivery. Microsponges were studied for colon targeting of drugs and genes. Additionally, MDS has wide application for sunscreen, cosmetics, and over the counter (OTC) products. Furthermore, MDS does not actuate any irritation, genotoxicity, immunogenicity or cytotoxicity. Therefore, this review extensively highlights about microsponges, their advantages, key factors affecting the micro-sponges' characteristics, the therapeutic application of microsponges in topical disorders, cancer, as cosmetics, recent advances in MDS and addresses the associated challenges.

Preparation and In Vitro-In Vivo Evaluation of Luteolin Loaded Gastroretentive Microsponge for the Eradication of Helicobacter pylori Infections

The current study aimed to develop a luteolin gastric floating microsponge for targeting Helicobacter pylori. The microsponge formulations were prepared by a quasi-emulsion method, and then evaluated for various physicochemical variables. The best microsponge was further assessed for drug-polymer interactions, surface morphology, in vivo floating, and in vitro anti H. pylori activity. The formulation which exhibited comparatively good production yield (64.45% ± 0.83), high entrapment efficiency (67.33% ± 3.79), prolonged in vitro floating time (>8 h), and sustained in-vitro drug release was selected as the best microsponge. The SEM study revealed that the best microsponge was spherical in shape and has a porous surface with interconnecting channels. DSC and XRD studies demonstrated the dispersion of luteolin in the polymeric matrix of the microsponge. Ultrasonography confirmed that the best microsponge could in the rat stomach for 4 h. The in vitro MIC results indicate that the anti H. pylori activity of the best microsponge was almost doubled and more sustained compared to pure luteolin. To conclude, it can be said that the developed luteolin gastric floating microsponge could be a better option to effectively eradicate H. pylori infections and the histopathological and pharmacodynamic assessments of our best microsponge can be expected to provide a rewarding outcome.

Gastro-retentive drug delivery systems: a recent update on clinical pertinence and drug delivery

Gastro-retentive drug delivery systems are some of the best technologies delivered through oral route. These mainly came into picture for their effective local action in the GI region, specifically for the drugs with narrow absorption window. In the recent decades, several technologies have evolved showing different mechanisms for retaining the drug in GI region for longer duration with increased bioavailability. Floatable, mucoadhesive, swelable, magnetic, nanofibrous, high-density, and expandable systems have been investigated extensively as the potential gastro-retentive strategies. The advances in the technologies studied, their clinical pertinence, and methods of drug delivery are described in this review with their immense future utilities. Their entry into the pharmaceutical market is a huge matter to look into as most of the studied strategies are facing problems and hence are underrated to overcome the clinical trials. Their success in the clinical trials are enormously required for gaining their access into the pharmaceutical market. Selection of the right technology for the right purpose through the right mechanism of action is to be done for obtaining the system with desired activity.

Microsponges for dermatological applications: Perspectives and challenges

Dermatological disorders have a huge psychosocial impact, causing significant impairment of patient's life. Topical therapy plays a pivotal role in management of such disorders. Conventional topical delivery systems result in overmedication/undermedication, leading to adverse effects and reduction in therapeutic efficacy. Consequently, researchers have been striving towards the development of alternative delivery systems for dermatological applications. In the last decade, microsponges emerged as an attractive option for topical delivery. Their characteristic particle size offers enhanced benefits, making them superior to the contemporary microcarriers. The present review furnishes a comprehensive account of state of the art, important factors affecting the performance and mechanism of drug release from topically applied microsponges, along with characterization techniques. Further, a list of marketed products and their applications for common dermatological disorders has been presented. All in all, this paper is an attempt to lay a bibliographic foundation for researchers working in this field and foster further investigations in this arena.

In vitro and ex vivo studies on diltiazem hydrochloride-loaded microsponges in rectal gels for chronic anal fissures treatment

Diltiazem hydrochloride, topically applied at 2% concentration, is considered effective for the treatment of chronic anal fissures, although it involves several side effects among which anal pruritus and postural hypotension. To test the hypothesis that a sustained delivery system of diltiazem hydrochloride may be helpful for the treatment of chronic anal fissures, in the present study we evaluated the potential of gels containing diltiazem hydrochloride entrapped in microsponges. Such microsponges were based on Eudragit RS 100 and the effect of some formulation variables was assessed by a 2³ full factorial screening design. An optimized formulation of diltiazem hydrochloride microsponges was dispersed in Methylcellulose 2% or Poloxamer 407 20% and the resulting gels (micro-l-diltiazem hydrochloride 2%) were subjected to in vitro drug release, ex vivo permeability and drug deposition after application on porcine rectal mucosa. The results showed a prolonged release up to 24 h from micro-l-diltiazem hydrochloride at 2% in the gels. The permeation tests revealed up to 18% higher drug retention on the mucosal tissue after 24 h by the micro-l-diltiazem hydrochloride 2% gels compared to conventional diltiazem hydrochloride gels at 2%. These results suggest that diltiazem hydrochloride-loaded microsponges dispersed in rectal gels may be useful to overcome some limitations of conventional local chronic anal fissure therapy.

Ocular administration of acetazolamide microsponges in situ gel formulations

In the present work, the antiglaucoma drug, acetazolamide, was formulated as microsponges in situ gel for ocular drug delivery aiming an improved therapeutic efficacy and reduction in the systemic side effects of oral acetazolamide. The microsponges were prepared by the quasi emulsion solvent diffusion method and were incorporated into 25% pluronic F-127 in situ gel. Ethyl cellulose polymer in different proportions with drug was used to prepare the microsponges. Different parameters were evaluated to select the best formulation. The formula S2 with drug to polymer ratio (2:1) showed high entrapment efficiency of about 82% and mean particle size of about 10 µm with polydispersity index (PDI) of 0.22, which are suitable characters for ocular delivery. The in situ gels were evaluated for physicochemical properties (pH, gelling capacity, gelation time and rheological properties) and in vivo studies. S2 formulation showed higher therapeutic efficacy compared to free drug in gel. It was non irritant to the rabbit's eye. These results indicated that acetazolamide microsponges in situ gel have potential ability for ophthalmic delivery.

Encapsulation of babchi essential oil into microsponges: Physicochemical properties, cytotoxic evaluation and anti-microbial activity

Babchi essential oil (BEO) is a valuable essential oil reported to possess a variety of biological activities such as antitumor, anti inflammatory, immunomodulatory, antioxidant, antifungal and antibacterial properties. Due to its anti-microbial properties, this oil possesses an immense potential for the treatment of dermatological disorders. Further, it has minimal tendency to develop resistance, a common issue with most of the antibiotics. However, its highly viscous nature and poor stability in the presence of light, air and high temperature, limits its practical applications. To surmount these issues, this research aims to encapsulate BEO in ethyl cellulose (EC) microsponges for enhanced stability, antibacterial effect and decreased dermal toxicity. The quasi emulsion solvent evaporation technique was used for fabrication of the BEO microsponges employing EC as polymer, polyvinyl alcohol (PVA) as stabilizer and dichloro methane (DCM) as solvent. The effect of formulation variables such as the amount of EC and PVA were also investigated. The prepared microformulations were evaluated for production yield, encapsulation efficiency, particle size and in vitro release. In vitro cytotoxicity was also checked to assess dermal safety of BEO microsponges. Results revealed that all the dispersions were in micro size range (20.44 ± 3.13 μmto 41.75 ± 3.65 μm), with good encapsulation efficiency (87.70 ± 1.20% of F2) and controlled release profile (cumulative drug release 73.34 ± 1.76%). Field emission scanning electron microscopy results showed that the microsponges possessed a spherical uniform shape with a spongy structure. Results of cytotoxicity study indicated that the prepared microsponges were safer on dermal cells in comparison to pure BEO. The optimized formulation was also evaluated for in vitro antimicrobial assay against dermal bacteria like Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, which confirmed their enhanced antibacterial activity. Furthermore, the results of photostability and stability analysis indicated improved stability of BEO loaded microsponges. Hence, encapsulation of BEO in microsponges resulted in efficacious carrier system in terms of stability as well as safety of this essential oil along with handling benefits.

Application of quasi-emulsification and modified double emulsification techniques for formulation of tacrolimus microsponges

Background

The present study was to develop a stable and sustained-release delivery system of tacrolimus (TCM). TCM is a macrolide antibiotic used as an immunosuppressant. It is formulated as a microsponge, which is a safe and effective delivery system with reduced side effects.

Materials and methods

The method used to prepare ethyl cellulose (EC) and xanthan gum (XG)-facilitated EC-based microsponges employed emulsification and modified double emulsification techniques. TCM-containing microsponges were prepared using varying concentrations followed by evaluation of micromeritics, compatibility of drug and excipients, production yield, drug content and entrapment efficiency, zeta potential, size distribution and drug release.

Results

The results showed excellent flow properties with adequate entrapment efficiency of the system and satisfactory release of active pharmaceutical ingredient. In vitro dissolution studies, which were conducted to determine the amount of drug released, illustrated a pronounced sustained effect up to 8 h. Zeta size and zeta potential analysis of microsponges confirmed the existence of micro-sized (1.99–3.09 µm) and stable particles (−15.33 to −3.38 mV), respectively.

Conclusion

Conclusively, the applied technique and selected combination of ingredients were found suitable for the preparation of TCM-containing sustained-release microsponges.

A Review About the Drug Delivery from Microsponges

Microparticulate drug delivery systems have shown a great interest in the pharmaceutical area. They allow the increase of drug therapeutic efficacy and the reduction of side effects. In this context, microsponges represent a new model of porous polymer microspheres, which allow the entrapment of a wide range of active agents. During the development, it is necessary the characterization of the system and among of the most important tests are the release and permeation profile analysis. They can demonstrate the behavior of drug in a specific site with a particular application condition and are related to therapeutic efficacy. Therefore, this review provides an overview of drug delivery profile from microsponges. Methods for determination of in vitro release and ex vivo permeation studies are detailed. Examples of drug delivery from microsponges administered in different sites are also discussed with aim to provide an understanding of the use of this strategy to modify the drug delivery.

Curcumin loaded microsponges for colon targeting in inflammatory bowel disease: fabrication, optimization, and in vitro and pharmacodynamic evaluation

The present study was aimed to develop and optimize the microsponges of curcumin for colon specific drug delivery in a view to bypass the upper gastrointestinal tract (GIT) for enhanced therapeutic effect. Microsponges were developed by quasi emulsion solvent diffusion method using 3(2) full factorial design. Prepared microsponges were optimized in order to analyze the effects of independent variables (volume of ethanol and Eudragit L100) on the encapsulation efficiency, particle size, and drug release. The optimized formulation was subjected to in vivo study using acetic acid induced colitis model in rats. The F7 was selected as optimized formulation based on particle size of 41.63 μm, % entrapment efficiency of 78.13%, and % cumulative drug release of 84.12%, and desirability factor of 0.83. Release studies revealed that microsponges prevented the premature release of curcumin in upper GIT and specifically released the drug at colonic pH. The drug release profile of F7 formulation was subjected to different kinetic models and based upon the best correlation coefficient (r(2) = 0.9927) the release was found to follow Higuchi model, which suggested diffusion as the main mechanism of drug release. Pharmacodynamic study showed that curcumin loaded microsponges causes a significant decrease in edema, necrosis, and hemorrhage of colon as compared to free curcumin. This study proves that curcumin loaded microsponges may act as a promising drug delivery system for treatment of ulcerative colitis.