Famotidine microspheres reconstituted with floating in situ gel for stomach-specific delivery: Preparation and characterization

Solid lipid nanoparticles cyclodextrin-decorated incorporated into gellan gum-based dry floating in situ delivery systems for controlled release of bioactive compounds of safflower (Carthamus tinctorius. L): A proof of concept study in biorelevant media

Safflower (Carthamus tinctorius L.) has been explored as a source of natural antioxidant. However, quercetin 7-O-beta-D-glucopyranoside and luteolin 7-O-beta-D-glucopyranoside, as its bioactive compounds, possessed poor aqueous solubility, limiting its efficacy. Here, we developed solid lipid nanoparticles (SLNs) decorated with hydroxypropyl beta-cyclodextrin (HPβCD) incorporated into dry floating gel in situ systems to control the release of both compounds. Using Geleol® as a lipid matrix, SLNs were <200 nm in size with >80 % of encapsulation efficiency. Importantly, following the decoration using HPβCD, the stability of SLNs in gastric environment was significantly improved. Furthermore, the solubility of both compounds was also enhanced. The incorporation of SLNs into gellan gum-based floating gel in situ provided desired flow and floating properties, with <30 s gelation time. The floating gel in situ system could control the release of bioactive compounds in FaSSGF (Fasted-State Simulated Gastric Fluid). Furthermore, to assess the effect of food intake on release behavior, we found that the formulation could show a sustained release pattern in FeSSGF (Fed-State Simulated Gastric Fluid) for 24 h after being released in FaSGGF for 2 h. This indicated that this combination approach could be a promising oral delivery for bioactive compounds in safflower.

Montmorillonite-Famotidine/Chitosan Bio-nanocomposite Hydrogels as a Mucoadhesive/Gastroretentive Drug Delivery System

The main purpose of the present study was to fabricate mucoadhesive bio-nanocomposite hydrogels to prolong the drug retention time in the stomach. In these bio-nanocomposite hydrogels, chitosan (CH) was used as a bioadhesive matrix, montmorillonite (MMT) was applied to modulate the release rate, and tripolyphosphate (TPP) was the cross-linking agent. The test samples were analyzed via different methods such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Drug incorporation efficacy and mucoadhesive strength of these nanocomposite hydrogel beads were studied. Swelling and in vitro drug release behaviors of these bio-nanocomposite hydrogels were evaluated in simulated gastric fluid (SGF; pH 1.2). The optimized MMT-famotidine (FMT)/CH bio-nanocomposite hydrogels displayed a controllable and sustainable drug release profile with suitable mucoadhesion and prolonged retention time in the stomach. Thus, the results demonstrated that the fabricated mucoadhesive bio-nanocomposite hydrogels could remarkably increase the therapeutic efficacy and bioavailability of FMT by the oral route.

A novel in vitro approach to investigate the effect of food intake on release profile of valsartan in solid dispersion-floating gel in-situ delivery system

Valsartan (VAL) is a BCS class II drug with low solubility and high permeability and, thus, its formulations often encounter low bioavailability problems. Its low bioavailability can be improved through enhanced formulation, such as incorporating it into a solid dispersion system (SD). The absorption can be further enhanced through gastroretentive systems. Herein, we developed a novel combination delivery approach consisting of floating in-situ gel and SD. VAL was incorporated with polymer carrier PVP and PEG 6000 and its solubility was then evaluated. The study found that VAL-SD containing PVP K-30 as the carrier with drug:PVP K-30 ratio of 1:3 shown highest solubility in different media. Moreover, DSC and XRD evaluations exhibited the change of VAL from crystal to amorphous following SD formulation. The SD was then formulated into floating in-situ gel preparations using sodium alginate as gel forming compound and HPMC as the controlled release matrix. The prepared VAL-SD floating in-situ gels were evaluated for their physical properties and drug release profile. The results showed that all physical evaluation of the floating in-situ gel formula possessed desirable physical properties and the use of HPMC in floating in-situ gel was able to sustain the in vitro release of VAL for 24 h in biorelevant media. Importantly, the effect of food intake on VAL release was also investigated, for the first time, showing that the VAL release could be controlled in FaSSGF (Fasted-State Simulated Gastric Fluid) in 2 h and FeSSGF (Fed-State Simulated Gastric Fluid) onwards. Thus, in can be hypothesized that the food intake did not affect the VAL release after 2 h in an empty gastric environment. Leading on from these results, in vivo studies in an animal model should be carried out to further assess the potency of this system.

Promising Polymeric Drug Carriers for Local Delivery: The Case of in situ Gels

BACKGROUND

At present, the controlled local drug delivery is a very promising approach compared to systemic administration, since it mostly targets the affected tissue. In fact, various drug carriers for local delivery have been prepared with improved therapeutic efficacy.

OBJECTIVE

in situ polymer gels are drug delivery systems that not only present liquid characteristics before their administration in body, but once they are administered, form gels due to gelation. Their gelation mechanism is due to factors such as pH alteration, temperature change, ion activation or ultraviolet irradiation. in situ gels offer various advantages compared to conventional formulations due to their ability to release drugs in a sustainable and controllable manner. Most importantly, in situ gels can be used in local drug delivery applications for various diseases.

METHODS

This review includes the basic knowledge and theory of in situ gels as well as their various applications according to their administration route.

RESULTS

Various natural, semisynthetic, and synthetic polymers can produce in situ polymeric gels. For example, natural polysaccharides such as alginic acid, chitosan, gellan gum, carrageenan etc. have been utilized as in situ gels for topical delivery. Besides the polysaccharides, poloxamers, poly(Nisopropylacrylamide), poly(ethyleneoxide)/ (lactic-co-glycolic acid), and thermosensitive liposome systems can be applied as in situ gels. In most cases, in situ polymeric gels could be applied via various administration routes such as oral, vaginal, ocular, intranasal and injectable.

CONCLUSION

To conclude, it can be revealed that in situ gels could be a promising alternative carrier for both chronic and immediate diseases.

In-vitro and in-vivo evaluation of polymeric microsphere formulation for colon targeted delivery of 5-fluorouracil using biocompatible natural gum katira

The aim was to develop oral site-specific rate-controlled anticancer drug delivery to pacify systemic side-effects and offer effective and safe therapy for colon cancer with compressed dose and duration of treatment. The double emulsion solvent evaporation method was employed. To check functionality, DAPI-staining and in-vivo anticancer study of Ehrlich Ascites Carcinoma bearing mice was tested. Histopathology of liver and kidney and Cell morphology of EAC cell was also performed. Formulated and optimized polymeric microsphere of 5-FU showed excellent physicochemical features. In-vitro, DAPI results pointed drug-treated groups displayed the prominent feature of apoptosis. The percentage of apoptotic of entrapped drug played in a dose-dependent manner. Significant decreases in EAC liquid tumors and increased life span of treated mice were observed. Rate of variation of cell morphology was more in 5-FU loaded microsphere than 5-FU injection. Hematological and biochemical parameter's and Histopathology of liver and kidney resulted that due to control released formulation have slow release rate, that gives less trace on liver and kidney function. Finally, we foresee that polymeric microsphere of 5-FU applying natural gum katira could be an assuring micro-carrier for active colon targeting delivery tool with augmented chemotherapeutic efficacy and lowering side effect against colon cancer.