Requirements: 1. Maintain the original format and structure. 2. The translation should be accurate, fluent, and natural. 3. Maintain professionalism and consistency. 4. Only provide the translation result; do not add any explanations. Original text: When AKG faced issues such as half-life, the blood-brain barrier, and stability, it had to make significant sacrifices. Although AKG-Ca improved in stability, its slow dissolution rate led to a delayed peak in blood drug concentration, and its lack of bone specificity also resulted in corresponding drawbacks. AKG and AKG-Ca liposomes—also known as lipoid microspheres—are ultra-small spherical vesicles formed by encapsulating active ingredients within a lipid molecular layer. They come in both nanoscale and micrometer sizes. Their core structure consists of a bilayer of phospholipids (the same material as cell membranes), cholesterol (for reinforcement), and the active ingredient, which is enclosed within either a “water compartment” or an “oil compartment.” The bilayer structure of liposomes perfectly mimics the human cell membrane, endowing them with unparalleled biocompatibility and viability. The liposomal phospholipid layer is resistant to stomach acid, increasing the efficiency of oral delivery by 3 to 5 times. Liposomes can disguise themselves as cell membranes to cross the blood-brain barrier, significantly increasing the concentration of active ingredients in the brain by 5 to 8 times. They also enable intelligent drug release, automatically releasing the active ingredient at different temperatures and pH levels. Liposomes act as a protective shield for the active ingredient, enhancing its antioxidant effects by 2 to 3 times. The optimal dosage forms for liposomes include: - **Enteric-coated capsules:** These have a dual-layer defense system. The outer enteric-coated gelatin shell dissolves at pH > 5.5, while the inner liposomes provide molecular-level protection. This design results in an almost 100% protection against stomach acid, a survival rate of the active ingredient of over 95%, and a peak blood drug concentration reached in just 45 minutes (2.7 times faster than with regular formulations). - **Oral liquids:** These use high-shear homogenization technology to produce liposomes with a particle size of ≤100 nm. Glycerol or trehalose is added as a cryoprotectant to ensure no loss of activity after rapid freezing at -196°C in liquid nitrogen. The liquid dissolves under the tongue in 3 seconds and enters the bloodstream in 30 seconds, with a bioavailability of 79% (compared to 28% for regular oral liquids). - **Multi-layered sustained-release microspheres:** These utilize three-dimensional release technology for precise, long-lasting drug delivery: a rapid-release layer (reaching peak in 30 minutes), a sustained-release layer (releasing the drug over 4–6 hours), and an enteric-coated layer that resists stomach acid erosion. This design reduces fluctuations in blood drug concentration and ensures the drug’s effectiveness for up to 8 hours. - **Granules:** These are designed to address swallowing difficulties in the elderly and children. Effervescent technology is used to create microbubbles; the reaction HCO₃⁻ + H⁺ → CO₂↑ + H₂O helps the liposomes adhere to the intestinal villi. The slightly acidic environment (pH 4.5–5.0) created by this process enhances the stability of the phospholipids by 300%. Liposomes offer numerous advantages for drug delivery, making them an excellent choice for various therapeutic applications.