Proteins and peptides (PPs) have gradually become more attractive therapeutic molecules than small molecular drugs due to their high selectivity and efficacy, but fewer side effects. Owing to the poor stability and limited permeability through gastrointestinal (GI) tract and epithelia, the therapeutic PPs are usually administered by parenteral route. Given the big demand for oral administration in clinical use, a variety of researches focused on developing new technologies to overcome GI barriers of PPs, such as enteric coating, enzyme inhibitors, permeation enhancers, nanoparticles, as well as intestinal microdevices. Some new technologies have been developed under clinical trials and even on the market. This review summarizes the history, the physiological barriers and the overcoming approaches, current clinical and preclinical technologies, and future prospects of oral delivery of PPs.
In this study, we investigate molecularly imprinted polymers (MIPs), which form a three-dimensional image of the region at and around the active binding sites of pharmaceutically active insulin or are analogous to b cells bound to insulin. This approach was employed to create a welldefined structure within the nanospace cavities that make up functional monomers by cross-linking. The obtained MIPs exhibited a high adsorption capacity for the target insulin, which showed a significantly higher release of insulin in solution at pH 7.4 than at pH 1.2. In vivo studies on diabetic Wistar rats showed that the fast onset within 2 h is similar to subcutaneous injection with a maximum at 4 h, giving an engaged function responsible for the duration of glucose reduction for up to 24 h. These MIPs, prepared as nanosized material, may open a new horizon for oral insulin delivery.
This project aims to synthesize and characterize the pH-sensitive controlled release of 5-fluorouracil (5-FU) loaded hydrogels (5-FULH) by polymerization of acrylamide (AM) and acrylic acid (AA) in the presence of glutaraldehyde (GA) as a crosslinker with ammonium persulphate as an initiator. The formulation’s code is named according to acrylamide (A1, A2, A3), acrylic acid (B1, B2, B3) and glutaraldehyde (C1, C2, C3). The optimized formulations were exposed to various physicochemical tests, namely swelling, diffusion, porosity, sol gel analysis, and attenuated total reflection-Fourier transform infrared (ATR-FTIR). These 5-FULH were subjected to kinetic models for drug release data. The 5-FU were shown to be soluble in distilled water and phosphate buffer media at pH 7.4, and sparingly soluble in an acidic media at pH 1.2. The ATR-FTIR data confirmed that the 5-FU have no interaction with other ingredients. The lowest dynamic (0.98 ± 0.04% to 1.90 ± 0.03%; 1.65 ± 0.01% to 6.88 ± 0.03%) and equilibrium swelling (1.85 ± 0.01% to 6.68 ± 0.03%; 10.12 ± 0.02% to 27.89 ± 0.03%) of formulations was observed at pH 1.2, whereas the higher dynamic (4.33 ± 0.04% to 10.21 ± 0.01%) and equilibrium swelling (22.25 ± 0.03% to 55.48 ± 0.04%) was recorded at pH 7.4. These findings clearly indicated that the synthesized 5-FULH have potential swelling characteristics in pH 6.8 that will enhance the drug’s release in the same pH medium. The porosity values of formulated 5-FULH range from 34% to 62% with different weight ratios of AM, AA, and GA. The gel fractions data showed variations ranging from 74 ± 0.4% (A1) to 94 ± 0.2% (B3). However, formulation A1 reported the highest 24 ± 0.1% and B3 the lowest 09 ± 0.3% sol fractions rate among the formulations. Around 20% drug release from the 5-FULH was found at 1 h in an acidic media (pH1.2), whereas >65% of drug release (pH7.4) was observed at around 25 h. These findings concluded that GA crosslinked 5-FU loaded AM and AA based hydrogels would be a potential pH-sensitive oral controlled colon drug delivery carrier.
Bacopa monnieri (Linn.) Wettst. (family Scrophulariaceae), a therapeutically important perennial herb, was transformed to study the stability of the effects associated with the insertion of a gene encoding b-cryptogein, a proteinaceous elicitor, either alone or in addition to the T-DNA genes in long-term in vitro culture as well as after transfer to the greenhouse. Plant lines BmAr-IXcrypt obtained via transformation by LBA 9402-crypt (pRi1855?pBin19??crypt) showed integration and expression of rolA, rolB, rolC, and rolD genes after 4 years of maintenance in vitro. The plant line BmAt-ncrypt obtained via transformation with A. tumefaciens strain LBA4404-crypt (harboring pBin19??crypt) as well as plant line BmAr-IXcrypt showed stable integration and expression of nptII gene and crypt gene even after transfer to greenhouse. The clones of Ri-crypt-transformed plants differed morphologically from Ri-transformed plants in that the typical ''hairy root syndrome'' was not observed in plants expressing crypt gene in the presence of rol genes. Except plant line BmAr-IXcrypt, none of the other transgenic plant lines showed any alteration in floral morphology and onset of flowering. The crypt-transformed plant lines (BmAr-IXcrypt and BmAt-ncrypt), maintained under long-term culture, showed significantly higher (p B 0.05) amount of bacoside production in vitro (1.66-to 2.05-fold, with respect to non-transformed plants). In addition, accumulation of all the four bacosides was significantly higher (p B 0.05) in crypt-transformed plants as compared to non-transformed plants grown for 1 year in greenhouse. Thus, the crypt-transformed plant lines of B. monnieri may be considered as the potential source for sustainable bioproduction of bacosides.
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