Development of tetracycline-serratiopeptidase-containing periodontal gel: formulation and preliminary clinical study

Advances and challenges in serratiopeptidase topical formulation

Enzymes are a key part of most metabolic processes and are required for the correct functioning of the human body, either directly or indirectly. Proteolytic enzymes aid in the digestion of proteins in the body. Proteolytic enzymes are created in the pancreas naturally, but they can also be found in certain diets. Serratiopeptidase is an enzyme found in the stomach wall of silkworms and produced from S. marcescens strain. Less solubility, toxicity, instability, incompatibility, and less penetration are all common issues with Serratiopeptidase drug delivery. Because of its proteinaceous nature, serratiopeptidase is susceptible to enzymatic breakdown in the gastrointestinal system. It also has a low permeability through the intestinal barrier due to its hydrophilic nature. Depending on the features of the medicine, a suitable delivery mechanism is required. Topical formulation may eliminate the risk of gastric degradation of drug and increase direct permeation through skin and show effects. Topical SRP may effectively lower inflammatory markers, as it has been found to have superior anti-inflammatory effects than topical NSAIDs. Serratiopeptidase topical formulations could be more effective than nonsteroidal anti-inflammatory medications in treating local inflammation. This article reviews studies on various topical formulations.

Supra and subgingival application of antiseptics or antibiotics during periodontal therapy

Periodontal diseases (gingivitis and periodontitis) are characterized by inflammatory processes which arise as a result of disruption of the balance in the oral ecosystem. According to the current S3 level clinical practice guidelines, therapy of patients with periodontitis involves a stepwise approach that includes the control of the patient's risk factors and the debridement of supra and subgingival biofilm. This debridement can be performed with or without the use of some adjuvant therapies, including physical or chemical agents, host modulating agents, subgingivally locally delivered antimicrobials, or systemic antimicrobials. Therefore, the main aim of this article is to review in a narrative manner the existing literature regarding the adjuvant application of local agents, either subgingivally delivered antibiotics and antiseptics or supragingivally applied rinses and dentifrices, during the different steps in periodontal therapy performed in Europe.

Optimization of In Situ Gel-Forming Chlorhexidine-Encapsulated Polymeric Nanoparticles Using Design of Experiment for Periodontitis

Periodontitis is a chronic inflammatory disease of the gums caused by pathogenic microorganisms damaging and destroying periodontal tissues. Chlorhexidine digluconate (CHX) is a commonly used antimicrobial agent for the treatment of periodontitis. However, it has many drawbacks, such as toxicity due to the high dosage required, low prolonged release, and low adhesion in the periodontal pocket. The objective of this study was to develop and optimize CHX-encapsulated polymeric nanoparticles (NPs) loaded into in situ gel-forming (ISGF) using design of experiment (DoE) to improve the treatment of periodontitis and overcome these limitations. CHX-NPs were optimized from 0.046%w/v chitosan, 0.05%w/w gelatin, and 0.25%w/w CHX. After that, the optimized of CHX-NPs was loaded into a thermosensitive ISGF, which was a mixture of 15%w/v Poloxamer 407 and 1% hydroxypropyl methylcellulose (HPMC). The optimized CHX-NPs, loaded into ISGF, was evaluated by measuring gelling temperature and time, pH, viscosity, compatibility, in vitro drug release, antibacterial activity, cytotoxicity, and stability. The results showed that the size, PDI, and zeta potential of optimized CHX-NPs were 53.07±10.17 nm, 0.36±0.02, and 27.63±4.16 mV, respectively. Moreover, the optimized ISGF loading CHX-NPs showed a gelling temperature at 34.3±1.2°C within 120.00±17.32 s with a pH value of 4.06. The viscosity of the formulations at 4°C was 54.33±0.99 cP. The DSC and FTIR showed no interaction between ingredients. The optimal formulations showed a prolonged release of up to 7 days while providing potential antibacterial activity and were safe for normal gingival fibroblast cells. Moreover, the formulations had high stability at 4°C and 25°C for 3 months. In conclusion, the study achieved the successful development of ISGF loading CHX-NPs formulations for effectiveness use in periodontal treatment.

Development of Transdermal Oleogel Containing Olmesartan Medoxomil: Statistical Optimization and Pharmacological Evaluation

Olmesartan medoxomil (OLM) is a first-line antihypertensive drug with low oral bioavailability (28.6%). This study aimed to develop oleogel formulations to decrease OLM side effects and boost its therapeutic efficacy and bioavailability. OLM oleogel formulations were composed of Tween 20, Aerosil 200, and lavender oil. A central composite response surface design chose the optimized formulation, containing Oil/Surfactant (SAA) ratio of 1:1 and Aerosil % of 10.55%, after showing the lowest firmness and compressibility, and the highest viscosity, adhesiveness, and bioadhesive properties (Fmax and Wad). The optimized oleogel increased OLM release by 4.21 and 4.97 folds than the drug suspension and gel, respectively. The optimized oleogel formulation increased OLM permeation by 5.62 and 7.23 folds than the drug suspension and gel, respectively. The pharmacodynamic study revealed the superiority of the optimized formulation in maintaining normal blood pressure and heart rate for 24 h. The biochemical analysis revealed that the optimized oleogel achieved the best serum electrolyte balance profile, preventing OLM-induced tachycardia. The pharmacokinetic study showed that the optimized oleogel increased OLM's bioavailability by more than 4.5- and 2.5-folds compared to the standard gel and the oral market tablet, respectively. These results confirmed the success of oleogel formulations in the transdermal delivery of OLM.

Serratiopeptidase: An integrated View of Multifaceted Therapeutic Enzyme

Microbial products have been used for the treatment of different diseases for many centuries. The serratiopeptidase enzyme provides a new hope for COVID-19-infected patients. Nowadays, anti-inflammatory drugs are easy to obtain at minimal expenditure from microbial sources. Serratia sp. is identified as one of the most efficient bacteria produced from serratiopeptidase. Screening for new and efficient bacterial strains from different sources has been of interest in recent years. Serratiopeptidase remains the most well-known anti-inflammatory drug of choice. Serratiopeptidase is a cheaper and safer anti-inflammatory drug alternative to NSAIDs. The multifaceted properties of serratiopeptidase may lead towards arthritis, diabetes, cancer and thrombolytic treatments. Existing serratiopeptidase treatments in combination with antibiotics are popular in the treatment of postoperative swelling. Although an exclusive number of serratiopeptidase-producing strains have been derived, there is an urge for new recombinant strains to enhance the production of the enzyme. This review explores the properties of serratiopeptidase, different therapeutic aspects, industrial production, and various analytical techniques used in enzyme recovery. In addition, the review highlights the therapeutic and clinical aspects of the serratiopeptidase enzyme to combat COVID-19-induced respiratory syndrome.

Formulation and development of Serratiopeptidase enteric coated tablets and analytical method validation by UV Spectroscopy

Serratiopeptidase (SRP) is a proteolytic enzyme that emerged as one of the most potent anti-inflammatory and analgesic drugs. The purpose of the present study was to formulate and evaluate enteric-coated tablets for SRP and investigate their stability using a simple and validated analytical method by ultraviolet (UV) spectroscopy. The colloidal silicon dioxide (2.50%), sodium starch glycolate (3.44%), and crospovidone (2.50%) were used as appropriate excipients for the development of core part of tablets. To protect the prepared tablets from acidic environment in the stomach, white shellac, castor oil, HPMC phthalate 40, and ethyl cellulose were used. The seal coating and enteric coating attained were 2.75% and 6.74%, respectively. SRP was found to be linear at 265 nm in the concentration range of 25–150 µg/mL. The results revealed that our developed method was linear (R² = 0.999), precise (RSD % = 0.133), and accurate (% recovery = 99.96–103.34). The formulated SRP tablets were found to be stable under accelerated conditions as well as under room temperature for 6 months (assay %: >97.5%). The in vitro drug release study demonstrated that enteric-coated tablets were able to restrict SRP release in both acidic environments: 0.1 N HCl and simulated gastric fluid (pH 1.2). Moreover, at 60 minutes, the formulated SRP tablets revealed 13.0% and 8.98% higher drug release in phosphate buffer (pH 6.8) and simulated intestinal fluid (pH 6.8), respectively, compared to the marketed tablet formulation. This study concludes that enteric-coated tablets of SRP with higher drug release in the intestine can be prepared and examined for their stability using validated analytical technique of UV spectroscopy.

An Overview on Thermosensitive Oral Gel Based on Poloxamer 407

In this review, we describe the application of thermosensitive hydrogels composed of poloxamer in medicine, especially for oral cavities. Thermosensitive hydrogels remain fluid at room temperature; at body temperature, they become more viscous gels. In this manner, the gelling system can remain localized for considerable durations and control and prolong drug release. The chemical structure of the poloxamer triblock copolymer leads to an amphiphilic aqueous solution and an active surface. Moreover, the poloxamer can gel by forming micelles in an aqueous solution, depending on its critical micelle concentration and critical micelle temperature. Owing to its controlled-release effect, a thermosensitive gel based on poloxamer 407 (P407) is used to deliver drugs with different characteristics. As demonstrated in studies on poloxamer formulations, an increase in gelling viscosity decreases the drug release rate and gel dissolution time to the extent that it prolongs the drug’s duration of action in disease treatment. This property is used for drug delivery and different therapeutic applications. Its unique route of administration, for many oral diseases, is advantageous over traditional routes of administration, such as direct application and systemic treatment. In conclusion, thermosensitive gels based on poloxamers are suitable and have great potential for oral disease treatment.

Soy Protein-Based Hydrogel under Microwave-Induced Grafting of Acrylic Acid and 4-(4-Hydroxyphenyl)butanoic Acid: A Potential Vehicle for Controlled Drug Delivery in Oral Cavity Bacterial Infections

The objective of this work was to evaluate grafted soy protein isolate (SPI) for pharmaceutical applications. The present work reports the microwave-assisted preparation of soy protein isolate\grafted[acrylic acid-co-4-(4-hydroxyphenyl)butanoic acid] [SPI-g-(AA-co-HPBA)] hydrogel via graft copolymerization using N,N-methylene-bis-acrylamide and potassium persulphate as the cross-linker and initiator, respectively. The chemical and physical properties of the synthesized polymeric hydrogels were analyzed by Fourier transform infrared spectroscopy, liquid chromatography-mass spectrometry (LCMS), nuclear magnetic resonance 1H-NMR, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The SEM, TEM, and XRD analyses have confirmed the formation of hydrogel SPI-g-(AA-co-HPBA) with the network structure having a layered and crystalline surface. The SPI-g-(AA-co-HPBA) hydrogel was investigated for the sustained and controlled drug delivery system for the release of model drug ciprofloxacin at basic pH for its utilization against bacterial infection in oral cavity. The drug release profile for SPI-g-(AA-co-HPBA) hydrogels was studied using LCMS at the ppb level at pH = 7.4. The synthesized hydrogel was found to be noncytotoxic, polycrystalline in nature with a network structure having good porosity, increased thermal stability, and pH-responsive behavior. The hydrogel has potential to be used as the vehicle for controlled drug delivery in oral cavity bacterial infections.

Comparative evaluation of 2% turmeric extract with nanocarrier and 1% chlorhexidine gel as an adjunct to scaling and root planing in patients with chronic periodontitis: A pilot randomized controlled clinical trial

Context

Nanoparticles, owing to their smaller size, penetrate regions inaccessible to other delivery systems, such as periodontal pockets. Thus, the present study aimed to comparatively evaluate efficacy of 2% curcumin with nanocarrier and 1% chlorhexidine gel as a local drug delivery (LDD) in the treatment of periodontal pockets.

Materials and Methods

Forty-five chronic periodontitis patients with pocket depth 5-7 mm in two or more teeth were selected. Full-mouth scaling and root planing (SRP) was done for all patients followed by random allocation to the three treatment groups, namely SRP group (Group 1), 2% curcumin with nanogel (Group 2), and 1% chlorhexidine gel (Group 3). Clinical parameter assessment and microbiological analysis of subgingival plaque samples for Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Tannerella forsythia (Tf) was done at baseline, 21^st day, and 45^th day.

Results

The results showed that when the two LDD agents were used as an adjunct to SRP in chronic periodontitis, there was an improvement in all clinical parameters. Evaluation of microbiological parameters also showed a significant reduction in Aa, Pg, and Tf levels. Comparison of 2% turmeric extract with a nanocarrier system with 1% chlorhexidine gel showed that both the agents had a comparable antibacterial effect on the three selected periodontopathic bacteria.

Conclusion

The present study showed that both the LDD agents showed an effective improvement of clinical and microbiologic parameters. 2% curcumin delivered with a nanocarrier system showed results comparable to chlorhexidine gel and hence shows promising future as an LDD agent in the treatment of periodontal pockets.

A 4-D approach for amelioration of periodontitis

Global prevalence of the severe periodontitis is at the alarming stage and its association with the systemic complications is highly evident which cannot be neglected. An insight into the pathophysiology of the periodontitis reveals that the promising amelioration could only be envisaged with the 4-D/multi-pronged approach of combining antibiotic along with the host modulating agents. The complications of the disease itself suggest that the use of antibiotic alone is not able to cater the symptoms completely. There is a need of other host modulatory agents too, such as Cyclo-oxygenase -II (COX II) enzyme inhibitors, Matrix metalloproteinase's (MMPs) inhibitors and osteo-integrating agents. Also, there is an unmet need of singular treatment modality through which all these agents can be sequentially and directly delivered into the periodontal cavity. The current hypothesis takes it a step forward wherein an antibiotic is combined with other three host modulatory agents in a singular drug delivery system. The encapsulation of multiple therapeutic agents with controlled release would therefore allow for reduced drug dose thus minimizing side effects; contributing to enhanced patient compliance and treatment efficacy. Hence this approach can be presented as a 4-D/multi-pronged approach for circumvention of periodontitis.

A Novel Thermoresponsive Gel as a Potential Delivery System for Lipoxin

The objective of this study was to evaluate a novel thermoresponsive polyisocyanopeptide (PIC)–based hydrogel as an injectable carrier for local drug delivery for periodontal applications. Three formulations of PIC gels, 0.2%, 0.5%, and 1% w/w, were prepared. As controls, commercially available poloxamer 407 (P407) gels of 20% and 26% w/w were used. Lipoxin A₄ (LXA₄), a proresolving drug, was suspended into the gel solutions. The systems were evaluated regarding dynamic mechanical properties, injectability and stability, release and bioactivity of LXA₄, and cytocompatibility. Results showed that the gelation temperatures of PIC and P407 gels were around 13°C to 23°C. PIC gels were less viscous and mechanically weaker than P407 gels due to the low polymer concentrations. However, PIC gels kept gel integrity for at least 2 wk when incubated with phosphate-buffered saline, whereas P407 gels were disintegrated totally within 1 wk. LXA₄ was chemically stable in both neutral and alkaline medium for over 1 mo. The release of LXA₄ from either 1% PIC or 26% P407 gels depicted an initial burst release followed by a sustained release for around 4 d. The extent of burst release was negatively correlated to the polymer concentration. LXA₄ remained bioactive after release from PIC gels. No cytotoxicity was observed for 1% PIC gel. However, 26% P407 inhibited periodontal ligament cell and gingival epithelial cell growth. In conclusion, the thermoresponsive PIC gel is a potential candidate for periodontal drug delivery.

Multiparticulate based thermosensitive intra-pocket forming implants for better treatment of bacterial infections in periodontitis

Considering alarming projections in the prevalence of periodontitis, following study was undertaken to develop chitosan-vanillin crosslinked microspheres loaded in-situ gel (MLIG) implants containing ornidazole and doxycycline hyclate for the treatment of pocket infections. Firstly, microspheres were formulated and optimized using response surface methodology for particle size <50 μm, entrapment efficiency >80%, in-vitro drug release (T_80%) >7 days and acceptable mucoadhesion. Further, MLIG were optimized for gelation temperature of 34-37 °C and viscosity <1000 cps respectively. FTIR, DSC and XRD graphs disclosed compatibility and alterations in crystallinity of drugs. In-vitro dissolution study demonstrated non-Fickian type of drug release mechanism for twelve days. Stability studies ascertained MLIG implants were sterilizable and stable for about 11.29 months on refrigeration. The formulations exhibited significant (p < 0.001) antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis, and were found biocompatible and biodegradable during preclinical studies. Ligature-induced periodontal rat model, corroborated significant growth (p < 0.05) of gingival tissue after two weeks. Clinical trials revealed, intra-pocket administration of MLIG along with SRP provided significant reduction in clinical parameters as compared to SRP alone. Conclusively, antimicrobials incorporated thermosensitive, biodegradable, mucoadhesive and syringeable MLIG implants appeared as better option for the treatment of periodontitis.

Formulation, in-vitro characterization and clinical evaluation of curcumin in-situ gel for treatment of periodontitis

This study aimed to develop syringeable in-situ curcumin (cur) gel for the treatment of periodontal pockets as well as to evaluate the clinical efficacy of Cur in-situ gel formulation. Different in-situ gel formulations of Cur were prepared using 30% of pluronic F127, and 1% of carbopol P934. The formulations were evaluated regarding gelation temperature, pH, viscosity, syringeability study, in-vitro release and chemical stability of cur. The effect of aging of gel formulations for 3months in refrigerator was investigated. The selected formulation was clinically evaluated through the determination of probing depth, plaque index, and bleeding index at baseline and 1 month after application. The formulations showed accepted gelation temperature ranging from 28 to 34 °C and all had pH value of 4. The viscosity of the formulations at 4 °C ranged from 19 000 to 37 000 cP. All formulations were easily syringeable through 21 gauge needle at cold temperature. Curcumin stability during the release study was maintained. Aging showed no significant effect on release profile, drug content, or the pH after 3 months, while it showed a slight increase in viscosity with concomitant decrease in gelation temperature. Selected formulations delivered into periodontal pocket evaluated clinically showed to be effective. The treated group revealed that the adjunctive use of intracrevicular 2% curcumin in-situ gel adjunct to mechanical treatment in patients with adult periodontitis could aid in significant clinical reduction of probing depth, bleeding index, and to less extent of plaque. This indicates that curcumin in this novel drug delivery system is an excellent candidate for periodontal disease treatment.

Analytical techniques for serratiopeptidase: A review

A review is presented on different analytical techniques used for qualitative and quantitative analysis of serratiopeptidase, a proteolytic enzyme, which has recently gained importance as an anti-inflammatory agent. Efforts have been made to collate all the relevant references to the extent possible. The review discusses the advantages and disadvantages of the cited analytical techniques, which will help to give insights into the methods used for estimation of serratiopeptidase as such, from clinical isolates and from its dosage forms. The review highlights the basic as well as advanced techniques performed for estimating serratiopeptidase. The techniques illustrated here have been demonstrated to be useful for qualitative and quantitative determination of serratiopeptidase and may find application in analyzing other related proteases.

Thermosensitive periodontal sol of ciprofloxacin hydrochloride and serratiopeptidase: Pharmaceutical and mechanical analysis

AIM

The aim of the present work was to explore the development of a dual-controlled release periodontal system of a potent broad spectrum first-generation fluoroquinolone, ciprofloxacin, and the anti-inflammatory enzyme serratiopeptidase (STP).

MATERIALS AND METHODS

Based on 3(2) full factorial design, thermoreversible periodontal sols capable of controlled dual delivery of ciprofloxacin hydrochloride and STP were designed using pluronic F127 and carbopol 934P as thermosensitive gelling polymers. Sol gel transition characteristics, %cumulative drug release at 48(th) h and exvivo mucoadhesive strength were designated as dependent responses. The sols were mucoadhesive, syringeable, and inverted into gels at simulated periodontal cavity temperature.

RESULTS

F9 with optimal drug release was identified as the best formulation. Extra design check point generated using Design Expert software 8.02 (Stat-Ease, USA) validated the experimental design. Textural analysis revealed that the developed sols were syringeable and spreadable enough for periodontal treatment so it can be expected that hardness and compressibility of sols would pose no problem during clinical application. The in vitro release behavior exhibited controlled release of both cipro HCl and STP (>90% release).

CONCLUSION

A dual-controlled release thermoreversible periodontal sol of ciproflaxin and STP was successfully developed. Incorporation of STP as anti-inflammatory agent has the potential of developing a therapeutically efficacious system of cipro HCl for treatment of periodontal inflammatory anaerobic infections.

Serratiopeptidase Niosomal Gel with Potential in Topical Delivery

The objective of present study was to develop nonionic surfactant vesicles of proteolytic enzyme serratiopeptidase (SRP) by adapting reverse phase evaporation (REV) technique and to evaluate the viability of SRP niosomal gel in treating the topical inflammation. The feasibility of SRP niosomes by REV method using Span 40 and cholesterol has been successfully demonstrated in this investigation. The entrapment efficiency was found to be influenced by the molar ratio of Span 40 : cholesterol and concentration of SRP in noisome. The developed niosomes were characterized for morphology, particle size, and in vitro release. Niosomal gel was prepared by dispersing xanthan gum into optimized batch of SRP niosomes. Ex vivo permeation and in vivo anti-inflammatory efficacy of gel formulation were evaluated topically. SRP niosomes obtained were round in nanosize range. At Span 40 : cholesterol molar ratio 1 : 1 entrapment efficiency was maximum, that is, 54.82% ± 2.08, and showed consistent release pattern. Furthermore ex vivo skin permeation revealed that there was fourfold increase in a steady state flux when SRP was formulated in niosomes and a significant increase in the permeation of SRP, from SRP niosomal gel containing permeation enhancer. In vivo efficacy studies indicated that SRP niosomal gel had a comparable topical anti-inflammatory activity to that of dicolfenac gel.

Texture and topography analysis of doxycycline hyclate thermosensitive systems comprising zinc oxide

To characterize the thermal behavior and texture analysis of doxycycline hyclate thermosensitive gels developed for periodontitis treatment containing zinc oxide prepared by using poloxamer (Lutrol^® F127) as polymeric material and N-methyl pyrrolidone was used as cosolvent. The thermosensitive gel comprising doxycycline hyclate, Lutrol^® F127, and N-methyl pyrrolidone were characterized for the thermal behavior and texture analysis. The topography of the system after the dissolution test was characterized with scanning electron microscope. Differential scanning calorimetric thermogram exhibited the endothermic peaks in the systems containing high amount of N-methyl pyrrolidone in solvent. The sol-gel transition temperature of the systems decreased as the zinc oxide amount was increased. The addition of doxycycline hyclate, zinc oxide, and N-methyl pyrrolidone affected the syringeability of systems. The addition of zinc oxide into the doxycycline hyclate-Lutrol^® F127 systems decreased the diameter of inhibition zone against Staphylococcus aureus, Escherichia coli, and Candida albicans since zinc oxide decreased the diffusion and prolonged release of doxycycline hyclate. From scanning electron microscope analysis, the porous surface of 20% w/w Lutrol^® F127 system was notably different from that of gel comprising doxycycline hyclate which had interconnected pores and smooth surfaces. The number of pores was decreased with increasing zinc oxide and the porous structure was smaller and more compact. Therefore, the addition of zinc oxide could increase the syringeability of doxycycline hyclate-Lutrol^® F127 system with the temperature dependence. Zinc oxide decreased inhibition zone against test microbes because of prolongation of doxycycline hyclate release and reduced size of continuous cells. Furthermore, zinc oxide also increased the compactness of wall surfaces of Lutrol^® F127.

Pharmacokinetics of an injectable long-acting parenteral formulation of doxycycline hyclate in pigs

Based on its ideal PK/PD ratios, doxycycline hyclate (DOX-h), a time-dependant antibacterial, is ideally expected to achieve sustained plasma drug concentrations at or slightly above the MIC level for as long as possible between dosing intervals. Pursuing this end, a poloxamer-based matrix was used to produce a 10% long-acting injectable preparation (DOX-h-LA) and its serum concentrations vs. time profile investigated after its injection to pigs in the pericaudal s.c. by parallel design. Results were compared with the forced oral bolus dose and i.v. pharmacokinetics of DOX-h. For this study, 12 recently weaned pigs per group were included in this trial, and a dose of 20 mg/kg was injected in all cases. DOX-h-LA showed the greatest values for bioavailability (115.38%); maximum serum concentration (Cmax) value was 1.5 ± 0.2 with a time to reach Cmax of 3.41 ± 0.04 h and an elimination rate constant of 70.93 ± 0.87( ) h. Considering minimum effective serum concentration of 0.5 μg/mL, a dose interval of at least 5 days can be achieved for DOX-h-LA, whereas p.o. and i.v. dosing of DOX-h may only last 11 and 15 h, respectively. Pigs were slaughtered on day 30 after this trial, and no visible remnants of the preparation were detected neither fibrosis was observed after a thorough macroscopic and histopathological analysis.

Preparation, characterization and targeted delivery of serratiopeptidase immobilized on amino-functionalized magnetic nanoparticles

Targeted delivery of serratiopeptidase enzyme immobilized on magnetic nanoparticles (MNPs) of Fe3O4 has been reported for the treatment using this enzyme. The enzyme was immobilized by covalent bonding through glutaraldehyde after amino functionalization of MNPs and parameters was studied. The enzyme bound MNPs (EMNPs) were characterized for size, crystallographic identity, phase purity, zeta potential and magnetic properties along with elemental and thermal analysis. The binding of enzyme had little effect on sizes (~10-17 nm) and on magnetic properties, but the zeta potential increased from -25 mV to +14.5 mV with surface amino groups up to 350 μmoles g(-1) MNPs, to stabilize its suspensions. In the molecular level, maximum of 17 molecules of enzyme could bind to each particle of MNPs that showed residual activity 67%, decreased KM and Vmax, good storage stability. Magnetic targeting of EMNPs increased the delivery (permeation) of drug through the membrane in in vitro study and enhanced the anti-inflammatory effect on carrageenan induced paw oedema in rats in in vivo study at much lower doses of enzyme than the doses required for treatment with free enzyme.

Characterization and Antimicrobial Activity of N-Methyl-2-pyrrolidone-loaded Ethylene Oxide-Propylene Oxide Block Copolymer Thermosensitive Gel

The purpose of this study is to investigate the effects of N-methyl-2-pyrrolidone on the thermosensitive properties of aqueous ethylene oxide-propylene oxide block copolymer (Lutrol^® F127) system. Due to the aqueous solubility enhancement and biocompatibility, N-methyl-2-pyrrolidone is an interesting solubilizer for the poorly water soluble drugs to be incorporated in the Lutrol^® F127 system. Effect of N-methyl-2-pyrrolidone on physicochemical properties of Lutrol^® F127 system was investigated using appearance, pH, gelation, gel melting temperature and rheology. The antimicrobial activity of the thermosensitive N-methyl-2-pyrrolidone gel was also tested. Lower N-methyl-2-pyrrolidone amount (≤30%w/w) could shift the sol-gel transition to a lower temperature but the gel-sol transition was shifted to a higher temperature. Higher N-methyl-2-pyrrolidone (≥40%w/w) could shift both sol-gel and gel-sol transitions of the system to a lower temperature. The amount of N-methyl-2-pyrrolidone >60% w/w could reverse the phase of the Lutrol^® F127 system to non-newtonian flow at 4° and Newtonian flow at high temperature. Aqueous Lutrol^® F127 system containing N-methyl-2-pyrrolidone exhibited antimicrobial activities against Staphylococcus aureus, Escherichia coli and Candida albicans with the N-methyl-2-pyrrolidone in a dose-dependent manner.

A new anti-infective strategy to reduce the spreading of antibiotic resistance by the action on adhesion-mediated virulence factors in Staphylococcus aureus

Staphylococcus aureus is a flexible microbial pathogen frequently isolated from community-acquired and nosocomial infections. S. aureus expresses a wide array of secreted and cell surface-associated virulence factors, including proteins that promote adhesion to damaged tissue and to the surface of host cells, and that bind proteins in blood to help evade immune responses. Furthermore, surface proteins have a fundamental role in virulence related properties of S. aureus, including biofilm formation. The present study evaluates the anti-infective capabilities of a secreted protein of Serratia marcescens (serratiopeptidase, SPEP), in impairing some staphylococcal virulence-related properties, such as attachment to inert surfaces and adhesion/invasion on eukaryotic cells. SPEP seems to exert its action by modulating specific proteins. It is not assessed if this action is due to the proteolytic activity of SPEP or to a specific mechanism which triggers an out/inside signal. Proteomic studies performed on surface proteins extracted from SPEP treated S. aureus cultures revealed that a number of proteins are affected by the treatment. Among these we found the adhesin/autolysin Atl, SdrD, Sbi, EF-Tu and EF-G. EF-Tu and EF-G are known to perform a variety of function, depending on their cytoplasmic or surface localization. All these factors can facilitate bacterial colonization, persistence and invasion of host tissues. Our results suggest that SPEP could be developed as a potential "anti-infective agent" capable to hinder the entry of S. aureus into human tissues, and also impairs the ability of this pathogen to adhere to prostheses, catheters and medical devices.

A clinical perspective on mucoadhesive buccal drug delivery systems

Mucoadhesion can be defined as a state in which two components, of which one is of biological origin, are held together for extended periods of time by the help of interfacial forces. Among the various transmucosal routes, buccal mucosa has excellent accessibility and relatively immobile mucosa, hence suitable for administration of retentive dosage form. The objective of this paper is to review the works done so far in the field of mucoadhesive buccal drug delivery systems (MBDDS), with a clinical perspective. Starting with a brief introduction of the mucoadhesive drug delivery systems, oral mucosa, and the theories of mucoadhesion, this article then proceeds to cover the works done so far in the field of MBDDS, categorizing them on the basis of ailments they are meant to cure. Additionally, we focus on the various patents, recent advancements, and challenges as well as the future prospects for mucoadhesive buccal drug delivery systems.

Comparison of the action of different proteases on virulence properties related to the staphylococcal surface

AIMS

The purpose of this study was to evaluate the antimicrobial efficacy of five different proteases belonging to two different families on Staphylococcus aureus and Staphylococcus epidermidis strains.

METHODS AND RESULTS

We used three serine proteases and two metalloproteases in single species biofilm formation assays and in human cell invasion processes. Following each protease incubation with bacterial cells, surface protein patterns were analysed by SDS-PAGE and zymography. Some differently expressed proteins were identified by mass spectrometry.

CONCLUSIONS

The effect of tested proteases on biofilm formation was not related to the protease category but was strain-dependent and was related to the biofilm formation capacity of each staphylococcal strain. Some proteases showed a nonspecific and indiscriminate effect on surface proteins, while others induced a discrete and reproducible action on protein profiles.

SIGNIFICANCE AND IMPACT OF THE STUDY

The inhibition of the surface-related virulence factors is a promising avenue to overcome persistent infections caused by bacterial biofilms. To this end, we show here that proteases, in particular the metalloprotease serratiopeptidase, can interfere with adhesion and invasion of eukaryotic cells and biofilm formation in staphylococci and their use could represent a viable treatment for the development of novel combination therapies.

Preparation of mucoadhesive oral patches containing tetracycline hydrochloride and carvacrol for treatment of local mouth bacterial infections and candidiasis

The specific aim of this work was to prepare mucoadhesive patches containing tetracycline hydrochloride and carvacrol in an attempt to develop a novel oral drug delivery system for the treatment of mouth infections. The bilayered patches were prepared using ethyl cellulose as a backing layer and carbopol 934 as a matrix mucoadhesive layer. Patches were prepared with different loading amounts of tetracycline hydrochloride and carvacrol. The antimicrobial activity was assessed for the prepared patches using the disc-diffusion method against the yeast Candida albicans and five bacterial strains, including Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus, Staphylococcus aureus, and Bacillus bronchispti. In this work, we highlighted the possibility of occurrence of a synergistic action between carvacrol and tetracycline. The best formulation was selected based on microbiological tests, drug release, ex-vivo mucoadhesive performance, and swelling index. Physical characteristics of the selected formulations were determined. These included pH, patch thickness, weight uniformity, content uniformity, folding endurance, and patch stability.

Microstructure and elution of tetracycline from block copolymer coatings

A critical metrology issue for pharmaceutical industries is the application of analytical techniques for the characterization of drug delivery systems to address interrelationships between processing, structure, and drug release. In this study, cast coatings were formed from solutions of poly(styrene-b-isobutylene-b-styrene) (SIBS) and tetracycline in tetrahydrofuran (THF). These coatings were characterized by several imaging modalities, including time-of-flight secondary ion mass spectrometry (TOF-SIMS) for chemical imaging and analysis, atomic force microscopy (AFM) for determination of surface structure and morphology, and laser scanning confocal microscopy (LSCM), which was used to characterize the three-dimensional structure beneath the surface. The results showed phase separation between the drug and copolymer regions. The size of the tetracycline phase in the polymer matrix ranged from hundreds of nanometers to tens of microns, depending on coating composition. The mass of drug released was not found to be proportional to drug loading, because the size and spatial distribution of the drug phase varied with drug loading and solvent evaporation rate, which in turn affected the amount of drug released.

Protease treatment affects both invasion ability and biofilm formation in Listeria monocytogenes

Listeria monocytogenes is a notably invasive bacterium associated with life-threatening food-borne disease in humans. Several surface proteins have been shown to be essential in the adhesion of L. monocytogenes, and in the subsequent invasion of phagocytes. Because the control of the invasion of host cells by Listeria could potentially hinder its spread in the infected host, we have examined the effects of a protease treatment on the ability of L. monocytogenes to form biofilms and to invade tissues. We have chosen serratiopeptidase (SPEP), an extracellular metalloprotease produced by Serratia marcescens that is already widely used as an anti-inflammatory agent, and has been shown to modulate adhesin expression and to induce antibiotic sensitivity in other bacteria. Treatment of L. monocytogenes with sublethal concentrations of SPEP reduced their ability to form biofilms and to invade host cells. Zymograms of the treated cells revealed that Ami4b autolysin, internalinB, and ActA were sharply reduced. These cell-surface proteins are known to function as ligands in the interaction between these bacteria and their host cells, and our data suggest that treatment with this natural enzyme may provide a useful tool in the prevention of the initial adhesion of L. monocytogenes to the human gut.