Development and optimization of gastroretentive mucoadhesive microspheres of gabapentin by Box–Behnken design

Experimental design, formulation, and in-vivo evaluation of novel anticoagulant Rivaroxaban loaded cubosomes in rats model

The aim of this study was to develop novel cubosomes as an oral delivery system to improve the permeation and anti-clotting activity of Rivaroxaban (RX). The experimental design (2³ full factorial design) was employed to study individual and combined impacts of the assigned formulation variables. The variables RX amount (X₁), Poloxamer (PX): GMO (GMO) ratio (X₂) and PX/GMO: water ratio (X₃) were taken as independent factors, and their effect was examined on entrapment efficiency (Y₁), particle size (Y₂), and zeta potential. (Y₃). The cubosomal vesicle RX-C 3 composed of RX (20 mg), PX: GMO (1:0.5 % w/w), and PX/GMO: water (1:5% w/w) is the optimised formula achieving the required prerequisites. RX-C 3 had shown a vesicle size of 91.2 ± 1.3 nm, entrapment efficiency of 96.27 ± 0.12 %, and zeta potential of -24.1 ± 0.2 mV. The in-vivo studies showed revealed good inhibition of blood clotting, where RX-C 3 significantly increased clotting time by 35% and prothrombin time by 29% compared to Rivarospire^®. In conclusion, the present study suggested that oral cubosomes formulations provide prolonged delivery of Rivaroxaban.

Antibacterial and Wound-Healing Activities of Statistically Optimized Nitrofurazone- and Lidocaine-Loaded Silica Microspheres by the Box-Behnken Design

In the current study, nitrofurazone- (NFZ) and lidocaine-loaded (LD) silica microspheres were fabricated to address pathological indications of skin infections. The microspheres were prepared by the sol–gel method applying the Box–Behnken design and evaluated for size distribution, morphology, zeta potential, physico-chemical compatibility, XRD, thermogravimetric analysis, antibacterial and cytotoxicity activities. The comparative in vitro drug release study of microspheres revealed a 30% release of NFZ and 33% of LD after 8 h. The microspheres showed 81% percentage yield (PY) and 71.9% entrapment efficiency. XRD patterns confirmed the entrapment of NFZ–LD in silica microspheres with a significant reduction in crystallinity of the drugs. Thermal and FTIR studies proved the absence of any profound interactions of the formulation ingredients. The smooth spherical microspheres had a −28 mV zeta potential and a 10–100 µm size distribution. In vitro antibacterial activities of the NFZ–LD microspheres showed an increased zone of inhibition compared to pure drug suspensions. The in vivo efficacy tested on rabbits showed a comparatively rapid wound healing with complete lack of skin irritation impact. The cytotoxicity studies revealed more acceptability of silica microspheres with negligible harm to cells. The study suggests that the NFZ- and LD-loaded silica microspheres would be an ideal system for accelerating and promoting rapid healing of various acute and chronic wounds.

Single step nanospray drying preparation technique of gabapentin-loaded nanoparticles-mediated brain delivery for effective treatment of PTZ-induced seizures

In the present study, gabapentin (GBP)-loaded chitosan nanosized particles were fabricated applying the nanospray drying technique. Different preparation parameters (spray mesh diameter, chitosan concentration and presence of D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) were studied while fixing other parameters (spraying rate, inlet temperature and gas flow rate). An optimized formulation with a particle size 107 ± 13 nm was obtained upon spraying 0.1% (w/v) chitosan solution containing 0.05% (w/v) of TPGS utilizing the small nozzle (4 μm spray mesh hole size). Drug entrapment efficiency and yield were as high as 95% and 83%, respectively. A 98.1 ± 6.1% (w/w) cumulative drug release was recorded after 2 h. Confocal laser scanning microscopy showed higher fluorescent dye penetration into brain tissue following intranasal administration of Rhodamine B labeled spray dried chitosan nanoparticles (NPs) as compared to Rhodamine B solution. Pentylenetetrazole (PTZ) was used to induce convulsions in rats through elevating seizure stages, releasing neuroinflammatory mediators and reducing excitatory amino acid transporter 2 (EAAT 2) and γ-aminobutyric acid (GABA) brain contents. Nanospray dried GBP-loaded chitosan NPs reduced seizure score, neuroinflammation; TNF-α and TGF-β, elevated EAAT 2 and GABA as well as decreased degeneration in pyramidal neurons compared to marketed product Conventin® capsules. Thus, it can be concluded from the aforementioned data that nanospray dried GBP-loaded chitosan NPs could comprise an appropriate treatment of epilepsy.

Mucoadhesive gastroretentive microparticulate system for programmed delivery of famotidine and clarithromycin

AIM

The present research was aimed to develop thiolated polyacrylic acid (TPA) based microspheres (MSPs) containing famotidine (FX) and clarithromycin (CLX).

METHODS

TPA was synthesised from polyacrylic acid and l-cysteine in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC). The prepared TPA was characterised using FT-IR (Fourier transform-infra red), ¹H-NMR (proton nuclear magnetic resonance) spectroscopy, P-XRD (powder X ray diffraction) method, and zeta potential. The analytical tools have supported the formation of TPA. The thiolated microspheres were prepared by emulsion solvent evaporation method using 0.75% w/v polymer concentration and stirring at 400 rpm for 8 hr.

RESULTS

The average particle size and zeta potential of optimised formulation was found to be 25.2 ± 1.87 μm and -26.68 mV, respectively. The entrapment efficiency of the optimised formulation was obtained 67.20% for FX and 70.20% for CLX. The developed microspheres were swelled only in 4 h from 0.5 to 0.9. The in vitro mucoadhesive study and in vitro drug release studies demonstrated that microspheres showed mucoadhesive property. In in vitro drug release studies, the release of FX and CLX were observed to be 58.68% and 60.48%, respectively from microspheres in 8 h. The thiolated microspheres showed higher adhesion time (7.0 ± 0.8 h) in comparison to the plain microspheres (2.6 ± 0.4 h).

CONCLUSION

The prepared TPA based mucoadhesive microspheres can be utilised as carriers for the treatment of peptic ulcer caused by Helicobacter pylori which will offer enhanced residence time for the rational drug combination in the gastric region.

Cubosomal based oral tablet for controlled drug delivery of telmisartan: formulation, in-vitro evaluation and in-vivo comparative pharmacokinetic study in rabbits

A nanoparticulate system; cubosomes has been suggested to support the controlled release of Telmisartan (TEL), a poorly water-soluble medication. Four distinctive formulae were selected according to the results of three estimated responses. The liquid cubosomes were successfully adsorbed onto Aerosil 380 to form granules. The formulae were evaluated for their flow properties. The best granules were compressed into tablets suitable for oral administration. The tablets were evaluated for its performance. The in vivo study of the best selected cubosomal tablets was checked after oral administration in the blood of albino rabbits utilizing an HPLC method. Results revealed that the highest EE was shown in formulae C5 (59.68 ± 1.3). All the prepared formulae had particle size less than 500 nm with PDI < 0.5 and the highest zeta potential results were observed in C5, C7, C9, C11 and C12 (>30 mv). A7 and A9 prepared using Aerosil 380 showed a perfect flowability. After 1 h of dissolution testing, the commercial product showed a 66% drug release while the release of all cubosomal formulae didn't exceed 35% during the first hour reaching a 85% of the drug released at the end of 24 h. A7 was selected for the in vivo study; T_max of TEL absorption is increased for cubosomal formula by three folds indicating sustained release pattern. The relative bioavailability is also increased by 2.6 fold. The investigation proposed the rationality of cubosome to figure an effective controlled release tablets to improve its bioavailability and expand its activity.

Optimization of microwave-assisted extraction conditions for preparing lignan-rich extract from Saraca asoca bark using Box-Behnken design

CONTEXT

Lyoniside is the major constituent of Saraca asoca Linn. (Caesalpiniaceae) bark. There is an immediate need to develop an efficient method to isolate its chemical constituents, since it is a therapeutically important plant.

OBJECTIVE

A rapid extraction method for lyoniside based on microwave-assisted extraction of S. asoca bark was developed and optimized using response surface methodology (RSM).

MATERIALS AND METHODS

Lyoniside was analyzed and quantified by high-performance liquid chromatography coupled with ultraviolet detection (HPLC-UV). The extraction solvent ratio (%), material solvent ratio (g/ml) and extraction time (min) were optimized using Box-Behnken design (BBD) to obtain the highest extraction efficiency. The optimal conditions were the use of 1:30 material solvent ratio with 70:30 mixture of methanol:water for 10 min duration.

RESULTS

The optimized microwave-assisted extraction yielded 9.4 mg/g of lyoniside content in comparison to reflux extraction under identical conditions which yielded 4.2 mg/g of lyoniside content. Under optimum conditions, the experimental values agreed closely with the predicted values. The analysis of variance (ANOVA) indicated a high goodness-of-fit model and the success of the RSM method for optimizing lyoniside extraction from the bark of S. asoca.

DISCUSSION

All the three variables significantly affected the lyoniside content. Increased polarity of solvent medium enhances the lyoniside yield.

CONCLUSION

The present study shows the applicability of microwave-assisted extraction in extraction of lyoniside from S. asoca bark.

Colloidal carriers for extended absorption window of furosemide

Objectives

The aim was to investigate the potential of self-microemulsifying drug delivery systems (SMEDDS) and niosomes as carriers for widening the gastrointestinal absorption window of furosemide (model acidic drug).

Methods

The drug was incorporated in SMEDDS and was encapsulated into niosomes. The intestinal absorption was monitored at two anatomical sites (duodenum and jejuno-ileum). This employed in situ rabbit intestinal perfusion technique.

Key findings

Perfusion of drug solution (control) revealed poor intestinal permeability with per cent fraction absorbed (%Fa) from the duodenum and jejuno-ileum being 1.3 and 0.6 % per cm, respectively. Formulation of furosemide as SMEDDS increased the %Fa from the duodenum and jejuno-ileum to reach 1.7 and 1 % per cm, respectively. Niosomal encapsulation increased the %Fa from duodenum and jejuno-ileum to record 1.9 and 1.2 % per cm, respectively. The increase in the %Fa was also revealed as a reduction in the length required for 95 % absorption of the drug which was reduced from 557.2 to 245.8 cm and to 279.8 cm after delivery as niosomes or SMEDDS, respectively, in case of jejuno-ileum. The same trend was recorded with the duodenum.

Conclusion

The recorded results highlighted the potential for SMEDDS and niosomes for widening the absorption window of acidic drugs after oral administration.

Nanovesicles of nitrendipine with lipid complex for transdermal delivery: pharmacokinetic and pharmacodynamic studies

CONTEXT

Vesicular transdermal delivery can enhance the bioavailability of a drug especially affected by first-pass metabolism, e.g. nitrendipine. However effective transdermal delivery employs permeation enhancer, e.g oleic acid (OA) with ceramide 2, stearic acid, behenic acid, and cholesteryl sulfate lipid complex.

OBJECTIVE

This study investigated the preparation, characterization of physicochemical properties, ex vivo permeation using human skin, pharmacokinetic parameters and antihypertensive potential in rats, of nitrendipine-loaded nanovesicles of ceramide 2, stearic acid, behenic acid and cholesteryl sulfate containing oleic acid gel (NOVG).

MATERIALS AND METHODS

The nanovesicles were made using film hydration method and characterized for physicochemical properties, ex vivo permeation using human skin, pharmacokinetic parameters and antihypertensive potential.

RESULTS

Nitrendipine-loaded nanovesicles of ceramide-2 containing oleic acid (NOV-5) have shown fluxes in the range of 4.88-24.72 μg/cm(2)/h nitrendipine oral suspension (NOS) at equal dose. NOVG-5 has shown almost 33% reduction in blood pressure in the first hour and a further decrease of 25% in the second hour to restore the normal pressure.

DISCUSSION

The permeation increases with increase in OA content. OA gets integrated in vesicle wall and enhances its permeability, whereas ceramide content makes sure that skin does not become damaged even after permeation.

CONCLUSION

NOVG-5 has shown the most favorable physicochemical properties and good permeation through skin providing good management of hypertension during crucial initial hours.

Formulation and evaluation of controlled-release of telmisartan microspheres: In vitro/in vivo study

The aim of this work was to design a controlled-release drug-delivery system for the angiotensin-II receptor antagonist drug telmisartan. Telmisartan was encapsulated with different EUDRAGIT polymers by an emulsion solvent evaporation technique and the physicochemical properties of the formulations were characterized. Using a solvent evaporation method, white spherical microspheres with particle sizes of 629.9–792.1 μm were produced. The in vitro drug release was studied in three different pH media (pH 1.2 for 2 hours, pH 6.8 for 4 hours, and pH 7.4 for 18 hours). The formulations were then evaluated for their pharmacokinetic parameters. The entrapment efficiency of these microspheres was between 58.6% and 90.56%. The obtained microspheres showed good flow properties, which were evaluated in terms of angle of repose (15.29–26.32), bulk and tapped densities (0.37–0.53 and 0.43–0.64, respectively), Carr indices and Hausner ratio (12.94–19.14% and 1.14–1.23, respectively). No drug release was observed in the simulated gastric medium up to 2 hours; however, a change in pH from 1.2 to 6.8 increased the drug release. At pH 7.4, formulations with EUDRAGIT RS 100 showed a steady drug release. The microsphere formulation TMRS-3 (i.e., microspheres containing 2-mg telmisartan) gave the highest C_max value (6.8641 μg/mL) at 6 hours, which was three times higher than C_max for telmisartan oral suspension (TOS). Correspondingly, the area under the curve for TMRS-3 was 8.5 times higher than TOS. Particle size and drug release depended on the nature and content of polymer used. The drug release mechanism of the TMRS-3 formulation can be explained using the Higuchi model. The controlled release of drug from TMRS-3 also provides for higher plasma drug content and improved bioavailability.