Protamine coated proliposomes of recombinant human insulin encased in Eudragit S100 coated capsule offered improved peptide delivery and permeation across Caco-2 cells.

In present investigation, recombinant human insulin loaded proliposomes and protamine sulphate coated proliposomes (rh insulin-proliposomes and Pt-rh insulin proliposomes) were encased in Eudragit S100 coated capsule to offer peptide release in simulated intestinal conditions. The particle size and zeta potential of Pt-rh insulin proliposomes were measured to be 583.2±10.2nm/+28.3±3.7mV significantly (P<0.05) higher than 569.7±14.9nm/-37.9±4.3mV and 534.6±24.6nm/-42.7±2.8mV of rh insulin proliposomes and proliposomes, respectively. Next, shape and surface morphology analysis pointed out the successful transformation of proliposomes in to spherical shaped liposomes. Furthermore, in vitro release study specified that free rh insulin solution encapsulated in uncoated gelatine capsule released 97.8% of peptide within 1h in SGF (pH~1.2). On other hand, rh insulin-proliposomes and Pt-rh insulin proliposomes encased in Eudragit S100 coated capsule released 93.2% and 81.6% of peptide, up to 24 h in SIF (pH~7.2). SDS-PAGE and circular dichroism (CD) ascertained the stability and intactness of isolated rh insulin from tailored dosage forms. In last, cellular uptake in Caco-2 cells indicating the superiority of Pt-rh insulin proliposomes in comparison to rh-insulin proliposomes and free rh insulin solution, respectively. In conclusion, Pt-rh insulin proliposomes displayed promising results and may be considered for further investigations.
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