# Nanoformulation of Peptides for Pharmaceutical Applications: In Vitro and In Vivo Perspectives
## 5 In Vivo Analysis of Nanoformulated Peptides
(2017) prepared doxorubicin-encapsulated mesoporous silica nanoparticles, which were surface-modified by polydopamine, and the CSNRDARRC peptide was decorated on the DOX-loaded MSNs@PDA for bladder cancer treatment. In this study, the HT-1376 cells were injected into male mice. It has been identified via histological studies that the DOX-loaded MSNs@ PDA and DOX-loaded MSNs@ PDA-PEP injected mice gained weight, where mice injected with DOX in the MSNs@ PDA-PEP sample remained healthy. After scarification of the mice, there were no morphological changes in the heart, liver, spleen, lung, and kidney. On the other hand, the mice injected with DOX-loaded MSNs@ PDA were weak and noticeable damages were identified in the organs. The results suggest that DOX-loaded MSNs@ PDA-PEP possesses antitumor effects and the peptide has the ability to control drug release toward the tumor cells [123]. Moreover, [PERSON] et al. (2020) incorporated the AP1 peptide with increased molecular weights of A38, A60, A86, and A100 on an elastin-like polypeptide polymer with a particle diameter of ~38-40 nm to exhibit antitumor activity. In vivo analysis results revealed that the peptide with a higher molecular weight retained for a longer period (up to 48 h) in the tumor cells; the peptide with a lower molecular weight retained for up to 12 h, where A86 and A100 reduced the volume of the tumor cells with low accumulation in the kidney, spleen, lungs, and heart of the mice model [124]. [PERSON] et al. (2014) constructed nano-lipid formulations of monomeric and trimeric peptides for the treatment of atherosclerosis. The drug was administrated through oral and intraperitoneal (IP) injection toward the low-density lipoprotein receptor (LDLr)-containing mice model. The mice were fed with chow diet for 10 weeks to increase their blood cholesterol levels and to induce atherosclerotic plaque in the aorta. The plasma cholesterol level study revealed that the administration of the nano-lipid formulation has led to a 50% decrease in the total cholesterol level for reducing the atherosclerotic plaque. Ip-administrated trimeric nanoparticles reduced the area of atherosclerotic lesions more than the monomeric lipid nanoparticles. It is evident from the in vivo studies that both administration routes helped to improve the effectiveness of the nano-lipid formulation in reducing the total cholesterol level [125]. Similarly, [PERSON] et al. (2016) studied the PEG-PLA nanoparticles, which were decorated by the iRGD peptide with a particle size distribution of 39 nm. In vivo studies showed that the peptide-decorated polymer nanoparticles possess the ability to enhance the antitumor activity by ~60% by inhibiting the cancer cell proliferation via the binding of \(\alpha\)v integrins with tumor endothelial cells, compared to normal cells [126]. Likewise, [PERSON] et al. (2014) conjugated iRGD-PCCD and prepared the CRGDKGPDC cyclopeptide, which was encapsulated in a PEGylated polyamidoamine (PAMAM) dendrimer. The in vivo studies revealed that the peptide-conjugated sample was released in the tumor blood vessels and their accumulation in the tumor cells were higher compared to nonconjugated samples. The peptide-conjugated drug induced the highest inhibition of tumor vascular growth and effectively reduced the volume of vascular tumor [127]. Further, [PERSON] and co-workers (2014) developed iNGR peptide-coated PEGylated PLGA nanoparticles for glioma treatment. In vivo studies showed that peptide-coated polymer nanoparticles possess high florescence intensity and anti-glioma efficacy, compared to uncoated nanoparticles. The nanoformulated samples were identified to be accumulated in the tumor sites and they penetrated deeply into the parenchyma of cancer cells due to their proteolytic cleavage into CRNGR and binding with NRP-1 [128]. Recently, [PERSON] and co-workers (2016) designed a pyroropheophide-a-conjugated polymeric drug, decorated with the F3 peptide. The peptide was shown to possess the ability to bind with nucleolin and it is expressed in tumor cells.