Pirfenidon yang dihantarkan secara peroral mengalami metabolisme lintas pertama, sehingga memerlukan dosis tinggi dan berpotensi menyebabkan efek samping sistemik. Oleh karena itu, pengembangan rute alternatif bagi pirfenidon perlu dilakukan. Penelitian sebelumnya melaporkan bahwa sistem penghantaran intrapulmonal berbasis solid lipid nanoparticles (SLN) dapat terdeposit dengan baik pada area alveolus paru-paru. Namun, karakteristik SLN dapat dipengaruhi oleh rasio lipid terhadap obat, jenis dan konsentrasi polimer. Oleh karena itu, optimisasi dengan metode permukaan respon perlu dilakukan untuk memperoleh formula SLN pirfenidon (P-SLN) yang optimal untuk penghantaran intrapulmonal. Lima belas formula disusun berdasarkan desain Box Behnken dengan tiga faktor yaitu, rasio lipid terhadap obat, jenis polimer dan konsentrasi polimer, serta tiga respon, meliputi ukuran partikel, PDI dan efisiensi penjerapan. Formula P-SLN optimal dikarakterisasi meliputi morfologi, kadar lembab, performa aerodinamik, studi disolusi dan stabilitas. Hasil optimisasi menunjukkan bahwa P-SLN optimal tersusun dari rasio lipid terhadap obat 6:1 dan 0,5% Plasdone K-29/32 (FO1). P-SLN FO1 memiliki bentuk sferis dengan ukuran partikel 212,67 nm, PDI 0,39, efisiensi penjerapan 95,02%, dan kadar lembab 1,59%. FO1 memiliki mass median aerodynamic diameter berkisar antara 0,54–12,12 μm. Selain itu, FO1 melepaskan pirfenidon sebanyak 89,61% dan 69,28% dalam medium pH 4,5 dan pH 7,4 selama 45 menit. Sebagai kesimpulan, FO1 terbukti memiliki karakteristik yang sesuai untuk menghantarkan pirfenidon melalui rute intrapulmonal.

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Orally administration of pirfenidone undergoes first-pass metabolism, hence requires high dose level and leads to systemic side effects. Therefore, it is necessary to develop an alternative route of administration for pirfenidone. Previous research reported that the solid lipid nanoparticle-based (SLN) intrapulmonary drug delivery system (IPDDS) was deposit well in the alveolar region of the lungs. However, the characteristics of SLN could be influenced by lipid-to-drug ratio, polymer type and concentration. Therefore, optimization using response surface methodology was carried out to obtain the optimized pirfenidon-loaded SLN (P-SLN) formula for IPDDS. Box-Behnken design was applied to create 15 formulas comprising three factors, including lipid-to-drug ratio, type and concentration of polymer and three responses, including particle size, PDI and entrapment efficiency. The optimized P-SLN formula was characterized, including morphology, moisture content, aerodynamic performance, dissolution and stability studies. The optimization results yielded an optimized P-SLN comprised a lipid-to-drug ratio of 6:1 and 0.5% Plasdone K-29/32 (FO1). The P-SLN FO1 had a spherical shape with a particle size of 212.67 nm, PDI of 0.39, entrapment efficiency of 95.02%, and moisture content of 1.59%. FO1 had a mass median aerodynamic diameter ranging from 0.54–12.12 μm. In addition, FO1 release 89.61% and 69.28% pirfenidone for 45 minutes in buffer medium pH 4.5 and pH 7.4. In conclusion, FO1 was proven to have an appropriate IPDDS characteristics for delivering pirfenidone.