Untitled

Abstract

Considering the importance of polymorphism occurring in solid dosage forms causing instability, the polymorphic behavior of spray-dried and -congealed lipid micropellets was examined by differential scanning calorimetry and scanning electron microscopy. The results showed that both of the spraying processes exert an important effect on their polymorphic and crystallization properties. In spray-drying, due to the rapid solvent evaporation, the obtained lipid micropellets possess an unstable polymorphic form. This unstable form transforms gradually toward a stable form by storage at elevated temperatures. The same modifications were observed with spray-congealed lipid micropellets. The type of glyceride (composition, chain length), solvent and drugs (estradiol cypionate, medroxyprogesterone acetate) and, further, the presence of a stabilizing agent such as lecithin affect the polymorphic transition and its rate.

Adsorption of Poly(Ethylene Glycol) Amphiphiles to Form Coatings Which Inhibit Protein Adsorption

“…Given the above, the authors have initiated investigations of promote their clearance by phagocytic cells resident in the adsorption of serum proteins at a wide range of native blood, liver, spleen, marrow, and other tissues (1)(2)(3). This and modified surfaces (21-27).…”

“…to study the in situ adsorption and formation of proteinrejecting coatings, of a series of purified, linear amphiphiles 1 To whom correspondence should be addressed.…”

Adsorption of Complement Proteins C3 and C1q

“…by their interactions with serum proteins and the reticuloenContact between serum and the surface of a macromole-dothelial system (RES) (2)(3)(4). Such interactions screen excule, biomaterial, or a colloidal drug carrier is sufficient to ogeneous particles and promote their clearance by phagotrigger hemostatic mechanisms such as coagulation and the cytic cells resident in blood, liver, spleen, bone marrow, and other tissues.…”

“…This adversely affects drug delivery via limited delivery to the target, and nonspecific accumulation in RES-including immunoglobulins (e.g., IgG), adhesins (e.g., fi-preparation. Ester purification involved repeated solvent extraction and Sephadex LH-20 gel exclusion chromatogbrinogen and fibronectin), and complement components (e.g., C3 and C1q) (2)(3)(4)(5)(6)(7). An inverse correlation has been raphy in methanol -water ( 4:1 v / v ) to remove any unreacted fatty acids from the product and to limit the ester noted between the serum protein adsorption and the circulation half-life of liposomal drug carriers (8)(9).…”

“…PEG head group molecular weight was determined by size-exclusion high pressure coated with certain phospholipids (e.g., phosphatidylinositol) or poly(ethylene glycol) polymers have been shown to liquid chromatography to be 6650 { 200, representing an average of 151 { 5 ethylene oxide ( EO ) units per molesignificantly reduce the adsorption of complement and opsonic proteins and are being studied as drug carriers by cule. The critical micellization concentration ( CMC ) was 12 { 3 mM ( 12 ) , while the ratio of mono-to diesterified various groups (2)(3)(4)(5)(6)(7)(8)(9).…”