A Brief Review on Microsponge Drug Delivery Systems: Innovations, Applications, and Future Directions

Omkar Dhembare*, Ashish Jain, Sofiya Moris.

Department of Pharmaceutics, Shri D.D. Vispute College of Pharmacy and Research Centre, New Panvel

Correspondence: omkardhembare13@gmail.com

INTRODUCTION

The microsponge drug delivery system was created in 1987. The microsponge medication delivery system is a patented polymeric device composed of porous microspheres.  These tiny spherical particles and interconnected spaces form a non-collapsible structure. The broad porous surface allows for controlled release of active substance. The pores range in size from 5 to 300 μm. The interior pore structure can measure up to 10 feet in length and has a capacity of ml/g. This results in a vast pool of storage.[1] These products often come in creams, gels, or lotions with high concentration of active chemicals. Recently, their utility in oral medication delivery has been studied. This page offers comprehensive information in the structure, development, applications, and future of microsponges. The oral route is the most popular and convenient method for medication delivery. The oral route is the most popular and convenient method for medication delivery. The oral route is the most popular and convenient method for medication delivery. The oral route of administration has gained popularity in the pharmaceutical industry due to its greater flexibility in dosage form formulation compare to other drug delivery methods.[2]

CHARACTERSTICS OF MICROSPONGE [3]

·         Microsponge compositions are stable through a PH range of 1-11.

·         Microsponge compositions are stable at temperatures of up 130°C.

·         Microsponge formulations self-sterilizing because to their average pore size of 0.25 µm, which prevents bacterial penetration.

·         Microsponge formulation offer a larger payload (50-60 %), are free flowing, and can be cost-effective.

·         The monomer should be fully miscible or can be rendered miscible with a tiny amount of water-immiscible solvent.

·         It should be water-immiscible or somewhat soluble.

ADVANTAGES [4]

Ø  Using microsponges instead of preservatives can improve the product shelf life and stability by preventing bacteria from entering.

Ø  Because of their highly segmented form, microsponges have a large internal surface area, resulting in a high pay loading capacity.

Ø  To make a substance appropriate for topical application on the skin, undesirable qualities such as oilness, tackiness, unpleasant sensations, and scents can be reduced significantly.

Ø  The ability to convert liquids into powder that flows smoothly provides advantages for handling materials.

Ø  Microsponges make the formulation more elegant.

Ø  Microsponges are non-collapsible structures composed of interconnected gaps with a huge porous surface.

Ø  Stable at temperatures of up to 130 °C and pH levels of 1 to 11.

Ø  Enhanced performance product.

Ø  Extended-release. Reduced irritation leads to better patient compliance.

Ø  The product now exhibits better thermal, physical, and chemical stability, as well as chemical stability, as well as enhanced elegance and formulation flexibility.

METHOD PREPARATION OF MICROSPONGES: [5,6]

A.    A quasi-emulsion solvent diffusion method:

This technique has a step between its outside and interior stages. The external phase consists of distilled water with surfactants. The interior phase consists of distilled water with surfactants. The interior phase consists of a drug, a polymer, and solvent.

Quasi emulsion solvent diffusion method.

Internal phase: Drug polymer + Solvent

       External phase:  Surfactant in distilled water.

Pour internal phase into external phase.

Stirring for 3 hrs. Filter suspension collect, microsponges

Microsponges dried in oven at 40°C.

Figure 1:  Preparation of Microsponges.

B.     Liquid-liquid suspension polymerization method: [7-11]

Microsponges are primed with the liquid-liquid suspension polymerization process. In this technique, the monomer and active compound are separated into the appropriate solvent. The solution is then stirred into the aqueous phase with surfactants. The polymerization procedure eliminates the solvent, resulting in spherical porous microsponges. As shown in fig no.2

                         Liquid-liquid suspension polymerization method

Monomers + Active ingredients dissolved in suitable solvent.

The solution is then dispersed in the aqueous phase.

Polymerization is initiated by adding catalyst or by increasing temperature.

Figure 2: Liquid-liquid suspension polymerization method

MECHANISM OF ACTION:

The active substance is introduced into the vehicle in an entrapped form. Because the microsponge particles have an open structure (i.e., there is no continuous membrane around them), the active can freely move in and out of the particles and into the vehicle until equilibrium is attained, when the vehicle becomes saturated. Once the completed product is applied to the skin, the active that is already in the vehicle will be absorbed into the skin, depleting the vehicle, which will become unsaturated, thereby disrupting the balance. This intimates a flow of the active from the microsponge particle into the vehicle and then to the skin, until the vehicle is either dried or absorbed. Even after that, the microsponge particles that remain on the surface of the stratum corneum will continue to gradually release the active to the skin, enabling extended release over time. This proposed mode of action emphasizes the need of developing vehicles suitable for usage with microsponge entrapments. If the active is excessively soluble in the intended vehicle during final product compounding, the benefits of progressive release will be lost. Instead they will act as if the active was added to the vehicle in its free from. As a result, when developing microsponge entrapments, it is critical to construct a vehicle with a minimum solubilizing power of the actives. This principle contradicts the normal formulation rules commonly used to topical treatments. For these traditional systems, it is usually recommended to increase the solubility of the active in the vehicle. When employing the microsponge entrapments, some active solubility in the vehicle is permissible since the vehicle can give the initial loading dose of the active until release from the microsponge is initiated by the polymer-carrier equilibrium shift. Another method for avoiding unwanted premature leaching of the active from the microsponge polymer is to construct the product with both free and entrapped active, resulting in a pre-saturated vehicle. In this instance, the active will not leach from the polymer during compounding. The rate of active release will ultimately be determined not only by the partition coefficient of the active ingredients between the polymer and the vehicle (or the skin), but also by certain of the beads’ characteristics. Examples of these include surface area and, particularly, mean pore diameter. Moisture, pH, friction, or temperature can all be used to control release.

FACTORS AFFECTING RELEASE MECHANISM: [13,14,15]

Pressure Triggered system:

Rub the microsponge formulation onto the damaged region to release the material it has trapped. The pressure trigger mechanism is influenced by the sponge’s characteristics, trapped material type, method and formulation.

Temperature Triggered system:

Increasing the temperature can increase the flow of an active component trapped in a microsponge, especially when there is too much sticky material, the possibility for a greater release of activity from microsponge as temperature increases.

PH Triggered system:

The pH of the formulation varies depending on where it is applied. The micro sponge’s coating may be adjusted to control the active substance’s pH-dependant release rate.

Solubility Triggered system:

Microsponge containing hydrophilic compounds that release active components when water is present. The rate of release depends on the external medium’s capacity to sustain the active, concentration gradient, or inflate the microspore network.

EVALUATION OF MICROSPONGES: -

1. Particle Size and Size Distribution: -

Laser diffraction, microfluidic resistance pulsed detection, electromagnetism zone, single-particle optical sensing, screening, dynamic light scattering, permeability to air diameter, and nanoparticle tracker analysis are among the methods used to analyse the particle size distribution. The particle size analysis approach is used to evaluate and visualise data on the size and distribution of a collection of particles that influence a formulation's texture and forecast material representations. The regulation of particle size distribution enhances the powder's flowability by reducing aggregates or polymerization during handling, packing, research quality assurance, and product development. With laser light diffractometry, it is possible to look at the particle size of both loaded and unloaded microsponges as well as their mean range of sizes and cumulative percentage of drug release. [19,20]

2. Morphology and Surface Topography: -

Photon correlation spectroscopy (PCS), a combination of transmission electron microscopy (TEM) and scanning electron microscopy (SEM), may be used to study the morphology and surface topography of microsponges. Surface morphology of gold-palladium-encrusted microsponges is examined in an argon environment at temperatures between 25 and 27 degrees Celsius.[20]

3. Percentage Entrapment: -

After being carefully weighed at 100 mg, the microsponges were pulverized, dissolved in 100 ml of methanol, and then sonicated.

The fluid was filtered with Whatman filter paper. After diluting the filtrate as necessary, the absorbance at 282 nm was measured in a UV-Vis Spectrophotometer with reference material set to methanol.[21]

           Entrapment efficiency (%) = Mact/Mthe) *100

 Where,

Mact is the actual amount of Terbinafine Hydrochloride in microsponges.

Mthe is the theoretical amount of Terbinafine Hydrochloride in microsponges

4. Percentage yield: -

Acquired a dried and independently weighed microsponge. The manufacturing yield of the microsponges was calculated by calculating the initial weight of the raw materials and the final mass of the microsponges. The formula utilized to calculate the production yield percentage was as follows: [22]

  Production Yield (PY) = Practical mass of microsponges / Theoretical mass (polymer + mass) *100

5. Diffusion Test: -

The drug release from microsponges is measured using a Franz diffusion cell. The drug release and penetration characteristics are analysed using membranes composed of animal skin (mouse, rat belly, and mucin) and synthetic membranes (cellulose acetate and silastic). Phosphate buffer is used as a dissolving solution at 37 °C in the receptor compartment and a microsponge composition is applied to the membranes in the donor compartment in order to conduct diffusion [23]

6. Dissolution tests: -

Using a modified basket made of 5μm stainless steel mesh, a dissolution test device may be used to study the microsponges' dissolution profile. The rotation is maintained at 150 revolutions per minute. In order to guarantee sink conditions, the dissolving medium is chosen with the solubility of the actives in mind. Analytical techniques appropriate for the task can be used to samples from the dissolving media at different

times.

MARKETED PRODUCTS USING MICROSPONGE DRUG DELIVERY SYSTEM

Table no.1 Marketed products using microsponge drug delivery system

APPLICATIONS OF MICROSPONGES: -

 A few uses of the microsponge medication delivery system are as follows:

v Microsponges in Oral Care Cosmetics:

Microsponge technology might be used in oral cosmetics to prolong the release of volatile compounds and enhance the ‘fresh feel’ experience. Microsponge containing such volatile chemicals can be readily included into toothpastes or mouthwashes.

v Long lasting-coloured cosmetics:

Colours entrapped in microsponges can enhance the longevity of cosmetic items like rouge and lipstick. As previously stated, microsponges aid in uniform distribution and increase covering power. Thus, colourful cosmetics made with microsponges would be extremely beautiful

v Going the natural way using a functional Active:

Consumers are increasingly interested in multifunctional natural components, while natural actives remain vital. Marinosomes®, liposomes derived from natural anti-inflammatory lipid extracts, have established a new paradigm for the use of such functional ‘active excipients. Using these compounds to create a microsponge structure looks cost-effective and inventive.

v Consumers are increasingly interested in multifunctional natural components, while natural actives remain vital. Marinosomes®, liposomes derived from natural anti-inflammatory lipid extracts, have established a new paradigm for the use of such functional 'active excipients'. Using these compounds to create a microsponge structure looks cost-effective and inventive.

CONCLUSION:

To summarize, the microsponge drug delivery system represents a substantial development in pharmaceutical technology, providing a diverse and effective route to drug administration. This technique improves the regulated release of active pharmaceutical components by using porous microspheres, resulting in better therapeutic results and fewer adverse effects. The capacity to adapt medication release patterns to individual demands enables for more precise therapy, possibly revolutionizing the management of a variety of medical disorders. Furthermore, the micro sponge system's versatility to many medication kinds and formulations indicates its potential for wider use. As research and development continue, improvements and advancements in microsponge technology may lead to even more successful and patient-friendly drug delivery options, indicating a bright future for this cutting-edge technique in pharmaceutical science.

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