Controlled Drug Release Studies of Atenolol Using Differently Sulfonated Acryloxyacetophenone and Methyl Methacrylate Copolymer Resins as Drug Carriers

2-Acryloxyacetophenone （AAP） was prepared and subjected to suspension polymerization with methyl methacrylate （MMA） using azobisisobutyronitrile （AIBN） as free radical initiator. The differently sulfonated AAP-MMA cross-linked copolymer cationic exchange resins were prepared by sulfonation with concentrated sulphuric acid at 70 ~C. Several characteristics of the prepared resins were evaluated, i.e. FTIR, the ion-exchange capacity （IEC）, thermo gravimetric analysis （TGA）, particle size distribution and microscopic morphology. The resin characteristics were altered with degree of sulfonation, providing that differently sulfonated resins could be prepared. The behavior of atenolol （ATL） loading and in vitro release in the USP stimulated gastric and intestinal fluids of the obtained resins were evaluated. The drug loaded in the resin increased with increasing degree of sulfonation and hence the drug binding site in resin employed. The drug release was lower from the resins with higher content of sulfonic group due to the increase in the diffusive path depth. The drug release was a little lower in stimulated gastric fluid （SGF） than in stimulated intestinal fluids （SIF）. The basic groups, ionized to a little greater extent in SGF and preferred binding with the resin rather than releasing. Hence, the differently sulfonated resins could be utilized as novel carriers for drug delivery.

Formulation and evaluation of a bioadhesive patch for buccal delivery of tizanidine

Tizanidine hydrochloride(THCl)is an antispasmodic agent which undergoes extensive first pass metabolism making it a possible candidate for buccal delivery.The aim of this study was to prepare a monolayered buccal patch containing THCl using the emulsification solvent evaporation method.Fourteen formulations were prepared using the polymers Eudragit■ RS 100 or EudragitB RL 100 and chitosan.Polymer solutions in acetone were combined with a THCl aqueous solution(in some cases containing chitosan)by homogenization at 9000 rpm for 2 min in the presence of triethyl citrate as plasticizer and cast in novel Teflon molds.Physicochemical properties such as film thickness,in vitro drug release and in vitro mucoadhesion were evaluated after which permeation across sheep buccal mucosa was examined in terms of flux and lag time.Formulations prepared using a Eudragit■polymer alone exhibited sa tisfactory physicomechanical properties but lacked a gradual in vitro drug release pattern.Incorporation of chitosan into formulations resulted in the formation of a porous structure which did exhibit gradual release of drug.In conclusion,THCl can be delivered by a buccal patch formulated as a blend of Eudragit■ and chitosan,the latter being necessary to achieve gradual drug release.

A novel cataplasma matrix of traditional Chinese medicine

The aim of this paper was to develop a cataplasma matrix that can be applicable to both watersoluble and liposoluble drugs.The gellan gum and konjaku were employed as the scaffold materials of the matrix.With polyacrylic acid sodium and oligosaccharides as tacktifier,the formula of the cataplasma matrix was optimized in the orthogonal method as:gellan gum 0.4 g,xanthan gum 0.03 g,konjac glue 0.1 g,glycerin 4 g,Gluco-Adhesive T(GAT)6 g,Gluco-Adhesive E(GAE)6 g,polyacrylic acid sodium 0.22 g,and sorbitol 3 g.The 180°peel strength,the tensile strength and the elongation at break was 3.043 N,0.275 MPa and 91.05%,respectively.Furthermore,the drug-compatibilities of the matrix were investigated with baicalin,berberine and curcumin,which were used as the models of hydrophilic,poor-water-soluble and hydrophobic ingredients.The drug contents could reach 4.12%,2.42%and 3.75%,while the in vitro release rate were measured as,361.79,55.85 and 104.41μg·cm^(-2)·h^(-1)for baicalin,berberine and curcumin,respectively.These results indicated that the obtained matrix had good drug-compatibility and drug-release properties for different ingredients.