Mucoadhesive Microspheres for Gastroretentive Delivery of Acyclovir: In Vitro and In Vivo Evaluation

Acyclovir (ACV), a model drug for this study, is one of the most effective drugs against viruses of the herpes group. Absorption of orally administered ACV is variable and incomplete, with a bioavailability of ca. 15-30%. The drug is absorbed in the duodenum after oral administration and hence, preparation of a floating drug delivery system (FDDS) for ACV may increase oral absorption of the drug. ACV matrix tablets (200 mg) containing an effervescent base (sodium bicarbonate and citric acid) and a binary combination of hydroxypropyl methylcellulose (HPMC) K4M with carbopol or sodium carboxymethyl cellulose (Na CMC) or polyvinylpyrrolidone (PVP) and/or sodium alginate were prepared by the direct compression method. The tablets were evaluated for physicochemical properties and in vitro floating ability (floating lag-time and duration), bioadhesiveness and drug release. The drug release studies were carried out in 0.1 N HCl (pH 1.2) at 37 0.5°C. At appropriate time intervals, samples were withdrawn and assayed spectrophotometrically at λ max 259 nm. The floating test showed tablets containing 15% effervescent base had a floating lag time of 10-30 s and a duration of floating time of 24 h. The formulations containing HPMC-PVP, HPMC-Na CMC, HPMC-carbopol, and HPMC-sodium alginate released about 60-90% of their drug content during a 12-h period. Increasing carbopol caused slower drug release. We concluded that the proposed tablets with 15% effervescent base, 20-30% HPMC, 30% Na CMC (and/or 20% PVP or 20% sodium alginate) showed good floating and drug release properties in vitro, and should be considered as FDDS for ACV.Key words acyclovir; floating drug delivery system; gastric residence time Considering their simple administration, oral drug dosage forms are the most commonly used drug delivery systems (DDS). The bioavailability of these dosage forms is affected by many different factors, of which one of the most important is their gastric residence time. In this respect, gastro retentive drug delivery systems (GRDDS), in which the drug is continuously released in the upper gastro-intestinal (GI), has attracted more attention in recent decades. Using GRDDS, many limitations of conventional oral dosage forms have been overcome. 1)Garg and Gupta 2) classified GRDDS into four main categories: a) gastric floating systems, b) expandable systems, c) bioadhesive systems and d) high density systems.Floating drug delivery systems (FDDS) consist mainly of two groups: 1) effervescent formulations, which produce carbon dioxide gas in contact with gastric contents, and 2) noneffervescent formulations which include hydrodynamically balanced systems, microporous systems, alginate beads, and hallow microsphere-microballoons.Moreover, superporous hydrogels and magnetic systems are categorized as gastric retaining oral delivery formulations. 2,3)FDDS offer various potential advantages for drugs which (i) have local gastric effects (such as misoprostol), (ii) are mainly absorbed in the stomach (e.g. furosemide), (iii) have an absorptio...

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“…10) Recently one study reported the application of multiple unit hollow floating microspheres for the oral sustained release of acyclovir.…”

mentioning

confidence: 99%

Development and Evaluation of a Monolithic Floating Drug Delivery System for Acyclovir

Tavakoli

Varshosaz

Dorkoosh

et al. 2012

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…100 nos. of dry microcapsules were placed on a clean glass slide and a few drops of liquid paraffin was added and covered with a glass slide and observed under a compound microscope using stage and ocular micrometer (Dhaliwal et al, 2008;.…”

Section: Particle Sizementioning

confidence: 99%

Formulation and evaluation of carvedilol microcapsules using Eudragit NE30D and sodium alginate

Bal

Sengupta

Murthy³

2013

Braz. J. Pharm. Sci.

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Inclusion complexes of carvedilol(CR) with hydroxyl propyl beta-cyclodextrin (HPBCD) was prepared using co-grinding technique. Then, the inclusion complex was microencapsulated using combinations of Eudragit NE30D (EU) and sodium alginate (SA) utilizing orifice gelation technique. The formulations were analysed by using Scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), Differential scanning Calorimetry (DSC) and X-ray diffractometer (XRD) and also evaluated for particle size, encapsulation efficiency, production yield, swelling capacity, mucoadhesive properties, zeta potential and drug release. The microcapsules were smooth and showed no visible cracks and extended drug release of 55.2006% up to 12 hours in phosphate buffer of pH 6.8, showing particle size within the range of 264.5-358.5 µm, and encapsulation efficiency of 99.337±0.0100-66.2753±0.0014%.The in vitro release data of optimized batch of microcapsules were plotted in various kinetic equations to understand the mechanisms and kinetics of drug release, which followed first order kinetics, value of "n" is calculated to be 0.459 and drug release was diffusion controlled. The mice were fed with diet for inducing high blood pressure and the in vivo antihypertensive activity of formulations was carried out administering the optimized formulations and pure drug separately by oral feeding and measured by B.P Monwin IITC Life Science instrument and the results indicated that the bioavailability of carvedilol was increased both in vitro and in vivo with the mucoadhesive polymers showing primary role in retarding the drug release.

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“…Mucoadhesive acyclovir microspheres were prepared by a emulsion-chemical crosslinking technique using chitosan, thiolated chitosan, Carbopol 71G and Methocel K15M (Dhaliwal et al, 2008). The microspheres showed release of 78.8 ±3.9% in 12 hours compared with a release of 90.5±3.6% in 1 hour from the drug powder.…”

Section: Mucoadhesive Microparticlesmentioning

confidence: 99%

“…(Dhaliwal et al, 2008) Chitosan microspheres containing lacidipine have also been evaluated in vitro for the treatment of pyloroplasm. The entrapment efficiency, using glutaraldehyde as the cross-linking agent, was between 14-40.82% and the microspheres exhibited a mucoadhesive property of over 70% in the in vitro wash off test using rat stomach mucosa.…”

Section: Mucoadhesive Microparticlesmentioning

confidence: 99%

Gastroretentive microparticles for drug delivery applications

Adebisi

Conway

2011

Journal of Microencapsulation

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Many strategies have been proposed to explore the possibility of exploiting gastroretention for drug delivery. Such systems would be useful for local delivery, for drugs that are poorly soluble at higher pH or primarily absorbed from the proximal small intestine. Generally, the requirements of such strategies are that the vehicle maintains controlled drug release and exhibits prolonged residence time in the stomach. Despite widespread reporting of technologies, many have an inherent drawback of variability in transit times. Microparticulate systems, capable of distributing widely through the GI tract, can potentially minimize this variation. While being retained in the stomach, the drug content is released slowly at a desired rate,

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Mucoadhesive Microspheres for Gastroretentive Delivery of Acyclovir: In Vitro and In Vivo Evaluation

Cited by 107 publications

References 30 publications

Development and Evaluation of a Monolithic Floating Drug Delivery System for Acyclovir

Development and Evaluation of a Monolithic Floating Drug Delivery System for Acyclovir

Formulation and evaluation of carvedilol microcapsules using Eudragit NE30D and sodium alginate

Gastroretentive microparticles for drug delivery applications

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