Liposomes collagens

Talk about milking a story. The newspapers got all excited when pop star Shania Twain revealed that the secret behind her soft, supple skin wasn t some complex, highly touted product filled with liposomes, collagen, or ceramides. The secret, she said, was udderly simple Bag Balm delivered the goods. Just as it had done for cow udders since 1908, when a small Vermont company decided to take the bull by the horns and tackle the chronic problem of chapped cow udders. 

Weiner, A., Carpenter-Green, S., Soehngen, E., Lenk, R., and Popescu, M., 1985, Liposome-collagen gel matrix A novel sustained drug delivery system, J. Pharm. Set 74 922-925. 

U Pleyer, B Elkins, D Ruckert, S Lutz, J Grammer, J Chou, KH Schmidt, BJ Mon-dino. (1994). Ocular absorption of cyclosporine A from liposomes incorporated into collagen shields. Curr Eye Res 13 177-181. 

Native chemical ligation also can be extended to the conjugation of peptides or proteins to other molecules or surfaces. For instance, Reulen et al. (2007) prepared liposomes that contained cysteine-PEG-phospholipid derivatives and then coupled thioester-modified peptides or proteins to form a protein-liposome conjugate. Using this procedure, approximately 100 molecules of a collagen binding protein could be coupled to the cysteine-containing liposomes. 

Pakkanen, T.M., Laitinen, M., Hippelainen, M., Hiltunen, M.O., Alhava, E. and Yla-Herttuala, S. (2000) Periadventitial lacZ gene transfer to pig carotid arteries using a biodegradable collagen collar or a wrap of collagen sheet with adenoviruses and plasmid-liposome complexes. J. Gene Med. 2, 52-60. 

Grammer et al. [120] studied collagen shield with dissolution times of 12 h, that were presoaked with either hydrophilic or lipophilic fluorophore (4,5-carboxyfluorescein and jV-[Lissamine rhodamine B sulfonyl]-diacyl-phosphatidylethanolamine, respectively), in a solution or unilamellar liposome suspension with different surface charges and bilayer fluidity. For the hydrophilic fluorophore, two to seven times higher concentrations were achieved in the collagen shield by immersion in aqueous solution than immersion in the liposome suspensions. 

The release kinetics data results indicated that liposome surface charge and bilayer fluidity are of minor importance for the interaction of liposomes with collagen shields. Moreover, the release kinetics of hydrophilic or lipophilic substance from collagen shield was similar for both liposome-encapsulated and nonencapsulated drug. Thus, these results suggest that there is no added value for combined application of collagen shields and liposomes. In another study, the combination of collagen shield and liposomes enhanced CsA ocular penetration but failed to provide sustained release compared to CsA liposomal suspension [121]. 

Grammer, J.B., et al. 1996. Impregnation of collagen corneal shields with liposomes Uptake and release of hydrophilic and lipophilic marker substances. Curr Eye Res 15 815. 

Liposomes to deliver cyclosporin A (CsA) have been incorporated into collagen shields. This delivery system provided the highest levels of CsA in both the cornea and sclera with higher levels in the aqueous humor compared to unencapsulated and capsulated CsA but not loaded into collagen shields. 

Yerushalmi, N., and Margalit, R. (1994), Bioadhesive, collagen-modified liposomes Molecular and cellular level studies on the kinetics of drug release and on binding to cell monolayers, Biochim. Biophys. Acta, 1189,13-20. 

The protective effects of liposome-entrapped superoxide dismutase and catalase have also been studied on bleomycin-induced collagen deposition in the lungs of mice (Ledwozyn, 1991). It has been suggested that liposomes might be good vectors for drugs in the treatment of bleomycin-induced fibrosis. 

Figure 182. 5(6)-Carboxyfluorescein leakage from liposomes during incubation at 20°C for 70 h in collagen-containing solutions as a function of collagen concentration. Lipid concentration O, 0,0.04% B, 0.4%. (Reproduced from Ref. 720 with permission.)...

The main applications of collagen as dmg delivery systems are components in ophthalmology, sponges for burns or wounds, pellets and tablets for protein delivery, gel formulation in combination with liposomes for sustained dmg delivery, as controlling material for transdermal delivery, and nanoparticles for gene delivery. ... 

Utility of collagen for sustained release of protein drugs was demonstrated by Weiner et al. (1985), who reported that enhanced retention of intramuscularly administered human growth hormone was measured in rats, upon incorporation of liposomal hormone in a dilute collagen gel. Increased duration of serum insulin levels in diabetic rats occurred with insulin-containing liposomes entrapped in 0.9% collagen, relative to liposomal insulin alone. Hori et al. (1989) showed that subcutaneous injection of insulin in a collagen gel increased plasma levels in rats (over a... 

D-Glucosidase has been immobilized and insolubilized with retention of enzymic activity by covalent reaction with cellulose cyclic imidocarbonate and chitosan, by attachment to collagen membranes, and by entrapment in liposomes, and in resealed eyrthocytes. ... 

---