As absorption enhancers

Ganem-Quintanar A, Quintanar-Guerrero D, Falson-Rieg F, Buri P (1998) Ex vivo oral mucosal permeation of lidocaine hydrochloride with sucrose fatty acid esters as absorption enhancers. Int J Pharm 173 203-210... 

In recent studies both in vitro (Caco-2 cells) and in vivo in rats, TMC with a degree of trimethylation of 60% was proven to be an excellent intestinal absorption enhancer of the peptide drugs buserelin and octreotide. The observed absolute bioavailability values were 13 and 16% for buserelin and octreotide, respectively [83] (impublished data Fig. 5). Permeation enhancing effects were more responsible for these increased bioavailabilities, rather than the mucoadhesive properties of the TMC polymers. Nevertheless, mucoadhesion is a prerequisite for these polymers in order to further act as absorption enhancers. 

Phospholipids, such as DPPC, act as absorption enhancers in the lung. A significantly higher reduction in blood glucose levels was observed with a DPPC-insulin physical mixture compared to liposome-insulin following intratracheal instillation into rats (Figure 10.5) (Mitra et al. 2001). In this study, insulin alone, 1 U/kg, resulted... 

Marttin, E., Verhoef, J. C., and Merkus, F. W. H. M. 1998. Ef cacy, safety and mechanism of cyclodextrins as absorption enhancers in nasal delivery of peptide and protein dtdgsug Target. 6 17-36. 

Rama Prasad, Y.V., et al. 2004. In situ intestinal absorption studies on low molecular weight heparin in rats using Labrasol as absorption enhancer. Int J Pharm 271 225. 

Other fatty acids as absorption enhancers have been reported. Ogiso et al. [112] demonstrated that lauric acid (C12) produced the largest increase in permeation rate, penetration coefficient, and partition coefficient of propranolol. Onuki et al. [113] reported that docosa-hexaenoic acid (DHA) has a strong insulin permeability enhancement effect and little toxicity, compared to oleic acid and eicosapentaenoic acid (EPA) using a water-in-oil-in-water (W/O/W) multiple emulsion with no or little mucosal damage. 

FIGURE 10.2 Bile salts used as absorption enhancer (deoxy-forms of these bile salts do not have the position 7 hydroxyl (OH ) group). 

Schipper, N.G.M., et al. 1999. Chitosans as absorption enhancers of poorly absorbable drugs 3 Influence of mucus on absorption enhancement. Eur J Pharm Sci 8 335. 

Schipper, N. G., Olsson, S., Hoogstraate, J. A., et al. Chitosans as absorption enhancers for poorly absorbable drugs 2. Mechanism of absorption enhancement. Pharm. Res. 14 923-929, 1997. 

A-Trimethyl Chitosan as Absorption Enhancer of Peptide Drugs. Ill... 

Van der Merwe, Verhoef, J.C., Kotze, A.F. and Junginger, H.E. (2004b) A-Trimethyl chitosan chloride as absorption enhancer in oral peptide drug delivery. Development and characterization of minitablet and granule formulations. Eur. J. Pharm. Biopharm. 57 85-91. 

Schipper NG, Olsson S, Hoogstraate JA, de Boer AG, Varum KM, Artursson P (1997) Chitosans as absorption enhancers for poorly adsorbable drugs 2 Mechanism of absorption enhancement Pharm Res 14 923-929... 

In view of their solubilizing effects and also their potential to change membrane permeability, surfactants have been considered as absorption enhancers, again mostly in animals. Polyoxyethylene ethers have been shown to enhance gastric or rectal absorption of linco-mycin, penicillin, cephalosporins, and fosfomycin in rats and rabbits. In rats, colonic absorption of interferon-alpha is increased from 3 to 8% by polyoxyethylene esters of oleic acid and oleic acid glycerides. 

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