Judul: Biodegradasi struktur dan morfologi mikrosfer polilaktat
Abstrak: Penggunaan mikrosfer radioaktif merupakan metode alternatif untuk mengobati kanker hati. Teknologi ini sudah mulai diaplikasikan dengan bahan dasar mikrosfer terbuat dari kaca atau keramik, namun keduanya tidak dapat terdegradasi dalam tubuh. Karena itulah diperlukan alternatif bahan lain yang dapat terdegradasi dalam tubuh, salah satunya ialah dengan memanfaatkan polimer biodegradabel, seperti polilaktat (PLA). PLA mempunyai sifat biodegradabel dan biokompatibel sehingga cocok digunakan sebagai bahan dasar pembuatan mikrosfer. Akan tetapi belum banyak pihak terutama di Indonesia yang mempelajari proses biodegradasi dan perubahan yang terjadi selama mikrosfer PLA terdegradasi sehingga penelitian tentang pengaruh biodegradasi terhadap perubahan struktur dan morfologi mikrosfer PLA akan sangat bermanfaat. Mikrosfer PLA dibuat dengan mengemulsikan 10 ml larutan PLA 10% dalam kloroform dan 10 ml larutan polivinil alkohol (PVA) 5% dalam air menggunakan motor pengaduk berkecepatan 1000 rpm, kemudian mendispersikannya dalam 500 ml akuades. Proses biodegradasi dilakukan secara in vitro pada pH 7.4 dan suhu 37°C. Proses degradasi mikrosfer PLA diamati melalui gejala kerusakan pada permukaan mikrosfer, penurunan entalpi pelelehan, penurunan bobot molekul, berturut-turut menggunakan scanning electron microscope, differential scanning calorimetry, dan gel permeation chromatography. Proses degradasi mikrosfer PLA tampak nyata setelah inkubasi selama 4 minggu. Jadi, PLA memenuhi syarat sebagai bahan baku pembuatan mikrosfer untuk digunakan sebagai pengungkung. Waktu 1 bulan itu cukup untuk proses terapi menggunakan mikrosfer radiofarmaka. Proses degradasi PLA berjalan lambat, hal itu disebabkan karena PLA yang digunakan bersifat kristalin dan adanya gejala munculnya sejumlah mikrosfer baru dari mikrosfer besar yang telah terdegradasi
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Judul: Degradasi in vitro mikrosfer polipaduan poli(asam laktat) dan poli (kaprolakton)
Abstrak: Poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) are examples of polymer that can be used as a matrix in drug delivery system because of its degradability property. Drug encapsulation system could be achieved by microspheres formation with emulsion method. The aim of this research was to examine in vitro degradation of microspheres obtained from PLA-PCL polyblend at pH 7.4. Several stages in the study consisted of PLA synthesis, mixing of PLA-PCL in polyblend, microspheres formation, shape and texture observation, and in vitro degradation test. Synthesis PLA produced a polymer with molecular weight 6064 g/mol. Microspheres were formed by emulsification with polyvinylalcohol (PVA) 1.5% (v/v) as an emulsifier. Physical texture of the microspheres was observed with stereomicroscope and scanning electron microscope (SEM). Degradation was analyzed weekly by measuring its molecular weight and viscosity using a digital viscometer, while its weight loss was measured using an analytical balance. The results showed that the composition of PLA microspheres: PCL (9:1) had degradation time faster than the others and it also affected morphological structure, viscosity, and weight of microsphere during degradation analysis. The higher the PLA composition the lower the viscosity value, therefore, the lower the molecular weight of microspheres. During degradation time, viscosity value and weight loss percentage decreased gradually. Kinetics of microsphere weight loss followed between zero and first order kinetic model.
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Judul: Estimation of Additive and Non-Additive Genetic Variances of Body Weight, Egg Weight and Egg Production for Quails (Coturnix coturnix japonica) with an Animal Model Analysis
Abstrak: This study estimates the additive and non-additive variances for egg production and body weight traits of two lines of quails from a long-term selection with the help of the REML method. For the body weight of 42-day-old females (BW42f) and males (BW42m), a total of 7,934 records for line 1 and 7,214 records for line 2 from 21 generations were used in our analyses. Additionally, 1,717 records of females from line 1 and 1,671 records of females from line 2 contained information on their egg production at an age of 42 to 200 days (EN200), on the average egg weight for the first 11 weeks of their laying season (EW1), on the average egg weight from weeks 12 to 23 (EW2), and on their body weight at an age of 200 days (BW200f). A multivariate additive animal model and one-trait dominance models, which include the inbreeding coefficients as covariates, were fitted to the data. The estimates of the heritability gained from our dominance models were smaller than those from the additive model. For line 1, the heritability values decreased for EN200 from 0.35 to 0.32, for EW1 from 0.66 to 0.56, for BW200f from 0.42 to 0.38, and for BW200m from 0.51 to 0.49, respectively. For the first line, the respective ratio (d2) of the dominance variance to the phenotypic variance for EN200, EW1, BW200f and BW200m was 0.08, 0.22, 0.09 and 0.21, and the values for the second line were 0.12, 0.06, 0.001 and 0.23.
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