• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.155-165
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• 1994

Some mucoadhesive polymers such as hydroxypropylcelluose (HPC) and carbopol-934 (CP) have been employed for the preparation of mucoadhesive polymeric systems, and their physical properties including mucoadhesion, swelling, and drug release were evaluated. A new simple experimental technique that can quantitatively measure the bioadhesive properties of various polymeric systems has been developed by the methods of detachment force test. As the polymeric systems, the discs of freeze-dried HPC/CP solid dispersions were prepared. The mucosa used in these tests were upper, middle, and lower parts of small intestine of male rats weighing $300{\sim}350\;g$. Detachment forces were increased as the mole fraction of CP increased in discs of HPC/CP solid dispersions. In the points of intestinal site dependence of mucoadhesion, the solid dispersions revealed non-specific mucoadhesion to the intestine. Swelling and drug release characteristics of mucoadhesive polymeric systems were studied extensively to find out the feasibility for the oral controlled delivery systems. Swelling ratio, expressed as the final height/initial height, has been determined in various pH buffer solutions. Hydrochlorothiazide (HCT) was employed as a model drug for release study. Apparent swelling and drug release rate constants, $K_s$ and $K_r$ respectively, were obtained from the square-root time plot of either swelling ratio or released amount of drug, particularly for the time periods before reaching the equilibrium. As a result, the swelling ratio of HPC/CP solid dispersions was increased as the weight percentage of CP increased. Similarly, the release of HCT from the solid dispersions was dependent on pH changes and CP contents, resulted in the slower release of HCT with the increases of pH and CP contents.

• Journal of Pharmaceutical Investigation
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• v.36 no.2
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• pp.83-87
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• 2006

Poly(acrylic acid) (PAA) was identified to possess good mucoadhesive properties ensuring its application to extend the retention times of the formulations at the oral cavity, intended route of administration using the polymer. In the noncross-linked state, PAA will swell and become eroded owing to the presence of salivary flow from the site of application. The formation of cross-links between the polymer chains will allow swelling but prevents the erosion of the dosage form. In the current study, cross-linking was achieved by esterification of the PAA chains with sucrose. The density of crosslinking was modified by changing sucrose concentration and the duration of cure time. The cross-linking density of the polymer hydrogel was assessed by equilibrium swelling studies. The mucoadhesion testing method allowed a comparative study of the hydrogels prepared. An inverse relationship between equilibrium swelling and peak detachment force showed that increased PAA chain density per unit area enhanced the mucoadhesive interaction.

• Korean Journal of Food Science and Technology
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• v.44 no.2
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• pp.191-195
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• 2012

Aminated gelatin microparticles were prepared with fucoidan at concentrations ranging from 0.5 to 2.0%. In order to acquire a higher primary amino group content regarding gelatin, gelatin was synthesized by using 1,2-ethylenediamine and free amino groups of aminated gelatin microsphere sample uncrosslinked or crosslinked with fucoidan have been determined by using trinitrobenzensulfonic acid (TNBS) methods. At the smallest fucoidan concentration, the free amino group content of the aminated gelatin microparticles was highest and decreased when fucoidan concentrations were increased. Furthermore, as concentration of fucoidan increased, the release from microparticles decreased. The $in$ $vitro$ gastric mucoadhesion of microparticles were evaluated by using fluorescent-labeled microparticles in an isolated and perfused mouse stomach. The gastric mucoadhesion of the aminated gelatin microparticles was significantly improved compared with that of gelatin microparticles.

• Polymer(Korea)
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• v.36 no.2
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• pp.182-189
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• 2012

In this study, poloxamer hydrogels were prepared by electron beam irradiation and evaluated for potential application as a buccal mucoadhesive drug delivery system. Poloxamer, one of typical thermoresponsive polymers, was modified to have vinyl end groups for crosslinking reaction, and its hydrogels were fabricated by irradiation crosslinking reaction. Carbopol as a mucoadhesive polymeric additive was introduced to improve the mucoadhesive property of the hydrogels and its effect on the mucoadhesion and drug release properties was investigated. The results showed that the end group modification of poloxamer and the addition of carbopol improved mucoadhesive force and mechanical properties and led to a sustained drug release behavior.

• Journal of Microbiology and Biotechnology
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• v.29 no.5
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• pp.721-730
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• 2019

The probiotic Lactobacillus acidophilus KBL409 was encapsulated with alginate (Al) and alginate-chitosan (Al/Chi) through extrusion method. The sizes and zeta potentials of microspheres were measured to confirm encapsulation. To evaluate the protective effect of microspheres against gastrointestinal fluids, all the samples were exposed to simulated gastric fluids (SGFs, pH 1.5) at $37^{\circ}C$ for 1 or 2 h, followed by incubation with simulated intestinal fluids (SIFs, pH 6.5) for 2 h. The mucoadhesive ability of microspheres was evaluated using the intestinal epithelial cell line HT29-MTX. To extend the shelf-life of probiotics, lyoprotectants such as disaccharide and polysaccharide were mixed with free or encapsulated cells during the freeze-drying process. The size of the microspheres demonstrated a narrow distribution, while the zeta potentials of Al and Al/Chi-microspheres were $-17.9{\pm}2.3$ and $20.4{\pm}2.6mV$, respectively. Among all the samples, Al/Chi-encapsulated cells showed the highest survival rate even after exposure to SGF and SIF. The mucoadhesive abilities of Al and Al/Chi-microspheres were higher than 94%, whereas the free L. acidophilus showed 88.1% mucoadhesion. Ten percent of sucrose showed over 80% survival rate in free or encapsulated cells. Therefore, L. acidophilus encapsulated with Al and Al/Chi-microspheres showed higher survival rates after exposure to the gastrointestinal tract and better mucoadhesive abilities than the free cells. Also, sucrose showed the highest protective effect of L. acidophilus during the freeze-drying process.

• Archives of Pharmacal Research
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• v.19 no.5
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• pp.386-389
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• 1996

The in vivo behaviour of phenylephrine hydrochloride in different vehicles like gels of Carbopol $907^circledR$, Carbopol $934P^circledR$ and latex system of cellulose acetate hydrogen phthalate(CAHP) was evaluated by measuring the reduction in intraocular pressure and the mydriatic activity. The parameters that haave been utilised to assess the performance of the formulations were the area under the curve (AUC), the maximum mydriasis $(I_{max})$, ethe time of maximum response $(T_{max})$ and the duration of activity (D). The influence of viscosity and mucoadhesion on the bioavailability parameters has also been investigated. Carbopol 934P and CAHP formulations showed prolonged duration of action and greater AUC compared to Carbopol 907 aqueous solution(P<0.05).

• Advances in Traditional Medicine
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• v.7 no.1
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• pp.51-64
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• 2007

Mucus is an aqueous gel complex with a constitution of about 95% water, high molecular weight glycoprotein (mucin), lipid, salts etc. Mucus appears to represent a significant barrier to the absorption of some compounds. Natural mucoadhesive agent was isolated and purified from the aqueous extract of the seeds of prosopis pallida (PP). Formulated tablet with the isolated material by wet granulation method. Some natural edible substances are in consideration for candidates as mucoadhesive agents to claim more effective controlled drug delivery as an alternative to the currently used synthetic mucoadhesive polymers. Subjected the materials obtained from natural source i.e. PP and standard synthetic substance, sodium carboxymethyl cellulose for evaluation of mucoadhesive property by various in vitro and in vivo methods. Through standard dissolution test and a model developed with rabbit, evaluated in vitro controlled release and bioadhesive property of theophylline formulation. Mucoadhesive agent obtained from PP showed good mucoadhesive potential in the demonstrated in vitro and in viνo models. The results suggest that the mucoadhesive agent showed controlled release properties by their application, substantially. In order to assess the gastrointestinal transit time in vivo, a radio opaque X-ray study performed in healthy rabbit testing the same controlled release formulation with and without bioadhesive polymer. Plasma levels of theophylline determined by the HPLC method and those allowed correlations to the in vitro mucoadhesive study results. Better correlation found between the results in different models. PP may acts as a better natural mucoadhesive agent in the extended drug delivery system.