Development of clindamycin loaded oral microsponges (Clindasponges) for antimicrobial enhancement: In vitro characterization and simulated in vivo studies

Clindamycin phosphate (CLP) is a broad-spectrum antibiotic that is used widely for different types of infections. It has a short half-life and hence it should be taken every six hours to ensure adequate antibiotic blood concentration. On the other hand, microsponges are extremely porous polymeric microspheres, offering the prolonged controlled release of the drug. The present study aims to develop and evaluate innovative CLP-loaded microsponges (named Clindasponges) to prolong and control the drug release and enhance its antimicrobial activity, consequently improving patient compliance. The clindasponges were fabricated successfully by quasi-emulsion solvent diffusion technique using Eudragit S100 (ES100) and ethyl cellulose (EC) as carriers at various drug-polymer ratios. Several variables were optimized for the preparation technique including the type of solvent, stirring time, and stirring speed. The clindasponges were then characterized in terms of particle size, production yield, encapsulation efficiency, scanning electron microscopy, FTIR spectroscopy analysis, in vitro drug release with kinetic modeling, and antimicrobial activity study. Moreover, in vivo, pharmacokinetics parameters of CLP from the candidate formula were simulated based on the convolution method and in vitro- in vivo correlation (IVIVC-Level A) was built up successfully. Uniform spherical microsponges with 82.3µm mean particle size with a porous spongy structure were evident. ES2 batch exhibited the highest production yield and encapsulation efficiency (53.75% and 74.57%, respectively) and it was able to exhaust 94% of the drug at the end of 8 hrs of the dissolution test. The release profile data of ES2 was best fitted to Hopfenberg kinetic model. ES2 was significantly (p< 0.05) effective against Staphylococcus aureus and Escherichia coli compared to the control. Also, ES2 displayed a twofold increase in the simulated AUC compared to the reference marketed product.

Microsponges: A Neoteric Approach for the Effective Management of Osteoarthritis

BACKGROUND

A microsponge delivery system (MDS) is a cutting-edge and distinctive method of structured medication delivery. Regulated drug distribution is now possible with the use of microsponge technology. Techniques for drug release are created specifically to distribute medications to the body's various locations. As a result, pharmacological therapy becomes more effective, and patient compliance significantly affects the health care system.

MAIN BODY

MDS consists of porous microspheres with a substantially porous structure and a very small spherical shape, ranging in size from 5 to 300 microns. MDS is typically used to administer medications through topical channels, but new research has demonstrated the promise of this technique for parenteral, oral, and ocular drug delivery. Topical formulations are an attempt to manage diseases like osteoarthritis, rheumatoid arthritis, psoriasis, etc. While reducing the drug's side effects, MDS can readily change the pharmaceutical release shape and enhance formulation stability. Reaching the highest peak plasma concentration in the blood is the main goal of microsponge medication delivery. The ability of MDS to self-sterilize is by far the most notable quality.

CONCLUSION

In countless studies, MDS is employed as an anti-allergic, anti-mutagenic, and nonirritant. This review covers the overview of microsponges along with their release mechanism. The article focuses on the marketed formulation of microsponges and patent data of the same. This review will be helpful for researchers working in MDS technology.

Preparation and Evaluation of a Microsponge Dermal Stratum Corneum Retention Drug Delivery System for Griseofulvin

Griseofulvin (GF) is used as an antifungal to treat superficial skin fungal infections such as tinea capitis and tinea pedis. Currently, GF is only available in traditional oral dosage forms and suffers from poor and highly variable bioavailability, hepatotoxicity, and long duration of treatment. Therefore, the main objective of this study was to reduce the side effects of the drug and to increase the concentration of the drug retained in the cutaneous stratum corneum (SC) and improve its efficacy through the preparation of drug-laden GF microsponge (GFMS). The emulsification-solvent-diffusion method was used to prepare GFMS, and the prescriptions were screened by a single-factor approach. The optimized formulation (GFF8) had a microsponge particle size (μm) of 28.36 ± 0.26, an encapsulation efficiency (%) of 87.53 ± 1.07, a yield (%) of 86.58 ± 0.42, and drug release (%) from 77.57 ± 3.88. The optimized microsponge formulation was then loaded into a Carbopol 934 gel matrix and skin retention differences between the microsponge gel formulation and normal gels were examined by performing skin retention and fluorescence microscopy tests. Finally, the hepatoprotective and cutaneous stratum corneum retention abilities of microsponge gel formulations compared to oral GF formulations were assessed by hepatotoxicity, pharmacokinetics, and tissue distribution studies. This provides a new perspective on GF dermal stratum corneum retention administration.

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.

Formulation and evaluation of hydroxypropylmethylcellulose-dicyclomine microsponges for colon targeted drug delivery: In vitro and in vivo evaluation

OBJECTIVE

The objective of present study was to design novel colon targeted delivery of dicyclomine Hydrochloride (DCH) microsponges.

METHODS

Microsponges (MS1-MS4) based on different ratios of hydroxypropylmethylcellulose (HPMC) and DCH was prepared by quasi-emulsion solvent diffusion method. Micro-sponges were analyzed by determining percent yield, encapsulation efficiency, drug content, drug-polymer compatibility and thermal stability. Kinetic analysis of thermal stability data was done by Chang method, Friedman method and Broido method. In vitro dissolution study was carried out at pH 1.2, pH 6.8 and pH 7.4 at different time intervals.

RESULTS

Results showed that there was no chemical interaction between DCH and HPMC in all microsponge formulations. Production yield, drug content and encapsulation efficiency were enhanced on increasing the drug-polymer ratio. Thermal stability of all the micro-sponges was greater than that of pure drug. In vitro drug release was decreased on increasing the polymer concentration at different pH levels. The newly prepared micro-sponges based on HPMC were confirmed as a promising means of colon targeted delivery of DCH. An HPLC method was developed and validated for the bioequivalence study of newly designed microsponges. Pharmacokinetics parameters were calculated using linear trapezoidal method after single oral administration of microsponges in white albino rabbits. Pharmacokinetics results indicate an enhancement in the value of t1/2, tmax, Cmax and AUC0-t of DCH in the microsponges as compared to standard DCH showing enhanced bioavailability of drug after microsponges formation.

CONCLUSION

The current study shows a new approach for colon specific delivery of DCH based on microsponges.

Formulation and optimization of microsponge-loaded emulgel to improve the transdermal application of acyclovir-a DOE based approach

The cutaneous penetration of acyclovir from the conventional topical formulations such as cream and ointments is poor due to low water solubility and low octanol buffer partition coefficient of the drug. The present investigation was aimed to prepare acyclovir-loaded microsponge-based emulgel to improve its topical delivery. The microsponges were prepared by the quasi-emulsion diffusion method. The central composite design was employed to investigate the effect of changes in various formulation and process parameters on critical product attributes. Homogenization speed (X1), drug/polymer ratio (X2), and concentration of PVA (X3) were selected as independent variables while particle size,b% yield, % drug loading efficiency, % entrapment efficiency, the drug released at 0.25 h and 6 h were selected as response variables. The regression analysis proved a significant effect of all the independent variables on the dependent variables (p < 0.05). All the designed batches released more than 40% drug in less than 1 h and were also able to sustain the drug release for more than 6 h. Based on the solution suggested by the software, the optimized batch was prepared with 1000-rpm homogenization speed, 1.6:1 drug/polymer ratio, and 0.088% of PVA. The optimized microsponge-loaded emulgel had acceptable viscosity (10,897 to 12,416 centipoise), spreadability (32.5 to 36.57 g × cm/s), pH (between 6 and 7), and drug content (93 to 95%). The results of the ex vivo permeation study proved significant improvement in drug permeation from optimized microsponge-loaded emulgel compared to the marketed formulation (f2 < 50).

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.

Formulation and evaluation of curcumin microsponges for oral and topical drug delivery

The aim of the present study was to improve the release rate of curcumin by microsponges prepared through quasi-emulsion solvent diffusion technique using ethylcellulose and PVA as carriers. The microsponges were characterized by FTIR, DSC, XRD and SEM studies followed by determination of total drug content and entrapment efficiency. The prepared microsponges were further filled in hard gelatin capsule shell and then loaded in carbopol gel to evaluate its potential in oral and topical drug delivery. Further, it was observed from the studies on release rate that microsponges filled in hard gelatin capsule shells (batch MS4) showed 93.2% release of curcumin whereas pure curcumin filled in capsule showed only 11.7% release in 8 h study. Furthermore, the microsponges loaded in carbopol gel were evaluated for ex vivo drug deposition studies and it was found that 77.5% of the curcumin was released within 24 h. The estimated drug remained in the skin was 207.61 ± 5.03 μg/cm2 as determined by a Franz diffusion cell. The drug release profile data were found to be fitted best into the zero-order model with anomalous transport mechanism of drug release in both cases.

Fabrication and Characterization of Sertaconazole Nitrate Microsponge as a Topical Drug Delivery System

Present study was taken up to develop a topical formulation that releases the drug in controlled manner, reduce the side effects associated with topical drug delivery and improve product efficacy with aid of microsponges. Microsponges loaded with sertaconazole nitrate were prepared by using quasi emulsion solvent diffusion with five different proportions of the polymer (Eudragit RS 100). The developed microsponges were analyzed for particle size, production yield, entrapment efficiency and drug content. Scanning electron microscopic images of microsponges revealed that they are spherical in shape and contain pores. Pore structure analysis was done by using mercury intrusion porosimetry technique, which confirmed the porous nature of microsponges. Microsponges were then incorporated in to a 1% corbopol gel and evaluated for pH, drug content, texture profile analysis and in vitro drug release. The batch F IV was found to be optimal as it shown 69.38% controlled drug release in 8 h that followed Higuchi model.

Microsponges based novel drug delivery system for augmented arthritis therapy

The motive behind present work was to formulate and evaluate gel containing microsponges of diclofenac diethylamine to provide prolonged release for proficient arthritis therapy. Quasi-emulsion solvent diffusion method was implied using Eudragit RS-100 and microsponges with varied drug–polymer ratios were prepared. For the sake of optimization, diverse factors affecting microparticles physical properties were too investigated. Microsponges were characterized by SEM, DSC, FT-IR, XRPD and particle size analysis, and evaluated for morphology, drug loading, in vitro drug release and ex vivo diffusion as well. There were no chemical interactions between drug and polymers used as revealed by compatibility studies outcomes. The drug polymer ratio reflected notable effect on drug content, encapsulation efficiency and particle size. SEM results revealed spherical microsponges with porous surface, and had 7.21 μm mean particle size. The microsponges were then incorporated in gel; which exhibited viscous modulus along with pseudoplastic behavior. In vitro drug release results depicted that microsponges with 1:2 drug–polymer ratio were more efficient to give extended drug release of 75.88% at the end of 8 h; while conventional formulation get exhausted incredibly earlier by releasing 81.11% drug at the end of 4 h only. Thus the formulated microsponge-based gel of diclofenac diethylamine would be a promising alternative to conventional therapy for safer and efficient treatment of arthritis and musculoskeletal disorders.