Mucoadhesives carbomers

Borchard, G. LueBen, H.L. deBoer, A. G. Verhoef, J. C. Lehr, C.-M. Junginger, H.E., The potential of mucoadhesive polymers in enhancing intestinal peptide drug absorption. Ill Effects of chitosan-glutamate and carbomer on epithelial tight junctions in vitro, j. Control. Rel. 39, 131-138 (1996). 

LueBen, H.L., Verhoef, J.C., Borchard, G., Lehr, C.-M., De Boer, A.G., and Junginger, H.E., Mucoadhesive polymers in peroral peptide drug delivery. II. Carbomer and polycarbophil are potent inhibitors of the intestinal proteolytic enzyme trypsin, Pharm. Res., 12 1293-1298 (1995). 

These stabilizers are added to the formulation in order to stabilize the emulsion formed during particle preparation. These stabilizers, however, can also influence the properties of the particles formed. The type and concentration of the stabilizer selected may affect the particle size. Being present at the boundary layer between the water phase and the organic phase during particle formation, the stabilizer can also be incorporated on the particle surface, modifying particle properties such as particle zeta potential and mucoadhesion (203). Other polymers have also been evaluated as stabilizers in earlier studies such as cellulosic derivatives methylcellu-lose (MC), hydroxyethylcellulose ( ), hydroxypropylcellulose (HPC), and hydroxypropylmethylcellulose (HPMC), as well as gelatin type A and B, carbomer and poloxamer (203). 

Chitosan has been shown to increase precorneal drug residence times. The cationic chitosan slows tear drainage by increasing viscosity and by mucoadhesion with the negatively charged mucin. Up to a threefold increase of the corneal residence time has been achieved by the addition of chitosan to topical vehicles [5]. Carbomer gels at 0.3% have also been shown to be effective in prolonging the tear film break-up time [6]. Hyaluronic acid has been reported to... 

Singla, A. K., Chawla, M., and Singh, A. Potential applications of carbomer in oral mucoadhesive controlled drug delivery system A review. Drug Dev. Ind. Pharm. 26 913-924, 2000. 

Luessen, H. L., de Leeuw, B. J., Langemeyer, M. W., de Boer, A. B., Verhoef, J. C., and Junginger, H. E. Mucoadhesive polymers in peroral peptide drug delivery. VI. Carbomer and chitosan improve the intestinal absorption of the peptide drug buserelin in vivo. Pharm. Res. 1996a 13, 11, 1668-1672. 

Carbomer is also compatible with dimethyl sulfoxide. The veterinary product, Domoso (Syntex Veterinary Labs), is a topical gel consisting of carbomer 934 and 90% dimethyl sulfoxide. Carbomer 940 gels exhibit superior optical clarity compared with 934 gels, and can be used in ophthalmic preparations. However, only carbomer 934 is approved for internal use. The mucoadhesive properties of carbomer were studied with triamcinolone acetonide, with acyclovir and to improve protein uptake across the nasal mucosa. Pharmaceutical gel products containing carbomer in their formulations are listed in Table 6. All are dermatological gels except for Anbesol Gel (Whitehall) and Pilopine HS (Alcon). 

Llabot JM, Manzo RH, Allemandi DA. Drug release from carbomer carbomer sodium salt matrices with potential use as mucoadhesive drug delivery system. Int J Pharm 2004 276 59-66. 

Poly(acrylic acid) (PAA) (Figure 16.5) is an anionic mucoadhesive polymer produced by the radical polymerization of acrylic add. PAA and its derivatives—weakly crosslinked PAAs, also known as Carbomers or Carbopol—are widely used in ophthalmic formulation, such as the ones used for the management of the dry eye condition. Generally, PAA and its derivatives are used in the preparation of mucoadhesive ocular drug delivery formulations [25], either in the form of viscous gels [26], nanoparticles... 

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