ABSTRACT
Developmental changes in children can affect drug disposition and clinical effects. A physiologically-based pharmacokinetic (PBPK) model is a mathematical model that can be used to predict blood drug concentrations in children and gain insight into age-dependent physiological differences in drug disposition impact. Pediatric PBPK (P-PBPK) models have attracted attention over the past decade. With the concerted efforts of academia, pharmaceutical companies, and regulatory agencies, there are more and more examples of pediatric clinical studies using PBPK models. Nevertheless, the number of P-PBPK models and their predictive performance still lag behind adult models. By referring to the literature, we study the process of children adapting to adult absorption, distribution, metabolism, and excretion (ADME) parameters and analyze the general principles of P-PBPK model establishment. In addition, we summarize the functions and application examples of commonly used P-PBPK modeling software to provide a basis for the rational application of modeling software.
ABSTRACT
In the research on cancer theranostics, most environment-sensitive drug delivery systems can only achieve unidirectional and irreversible responsive changes under pathological conditions, thereby improving the targeting effect and drug release performance of the delivery system. However, such irreversible changes pose potential safety hazards when the dynamically distributed delivery system returns to the blood circulation or transports to the normal physiological environment. Intelligent reversible drug delivery systems can respond to normal physiological and pathological microenvironments to achieve bidirectional and reversible structural changes. This feature will help to precisely control the drug release of the delivery system, prolong the blood circulation time, improve the targeting efficiency, and avoid the potential safety hazards of the irreversible drug delivery system. In this review, we describe the research progress of intelligent reversible drug delivery system from two main aspects: controlled drug release and prolonged blood circulation time/enhanced cellular internalization of drug.
ABSTRACT
The drug delivery system with "gatekeeper" is designed to achieve a stable entrapment state of the payload under normal physiological conditions through the gatekeepers. With tumor microenvironment or stimulation of exogenous factors, the gatekeeper is detached or altered to promote the responsive release of the drug. In this paper, we focus on applications of stimuli-responsive linkages and stimuli-responsive groups, and review research progresses of drug delivery system with "gatekeeper" developed over the past 10 years.
ABSTRACT
Extracellular acidity has been associated with many pathological states, such as cancer, ischemic stroke, neurotrauma and infection, which makes it an effective target for therapy and diagnosis of such diseases. As a polypeptide vector, pH low insertion peptides (pHLIPs) are endowed with high sensitivity to extracellular acidic environment, which can insert the membrane and deliver payload to pathological cells in a pH dependent manner. Here, theranostic applications of pHLIP in disease, are reviewed in two aspects:pHLIP-mediated single-molecule transporter and nano-sized carrier.
ABSTRACT
The key of gene therapy is to deliver the functional gene to the target tissue in the body. The safe and efficient gene carrier is particularly important in the targeted delivery. Multifunctional envelope-type nano device (MEND), based on concept "Programmed packaging", is a new type of gene carrier system, with high encapsulation efficiency, favourable stability, high transfection efficiency, easy preparation, etc. MEND is designed to control intracellular trafficking as well as the tissue distribution of encapsulated compounds such as nucleic acids/proteins/peptides, permitting them to function at the appropriate location. In this paper, research progresses in MEND are reviewed in accordance with three types of payloads:the small interfering RNA (siRNA), DNA and proteins/peptides in recent years.
ABSTRACT
Cell-penetrating peptides are composed of positively-charged amino acids that can mediate molecules or nano-carriers across cell membranes. However, most of the known cell-penetrating peptides have no cell-or tissue-specificity, with affinity to almost all types of cells in internalization. The non-specificity of cell-penetrating peptides is a significant obstacle in the application to targeted delivery of imaging probes and therapeutic agents. Accordingly, many studies focused on selective switching of systemically-delivered inert cell-penetrating peptides into active forms in diseased tissues. Tsien groups introduced the concept of activatable cell-penetrating peptides in 2004. Subsequently, a growing number of similar delivery systems (molecular or nano-sized) have been documented, and the sensitive factors have included enzyme, lower pH, light and exogenous component. In this paper, we make an overview of the development of activatable delivery system in recent years.
ABSTRACT
Cell-penetrating peptides (CPPs) offer a non-selective and receptor-independent mode to promote cellular uptake. Although the non-specificity of CPP-mediated internalization allows this approach applicable to a wide range of tumor types potentially, their universality is a significant obstacle to their clinical utility for targeted delivery of cancer therapeutics and imaging agents. Accordingly, many reports have focused on selective switching of systemically delivered inert CPPs into their active form in lesions (tumor). In this review, our attention is mainly confined to such an enzyme-sensitive domain incorporated delivery system with activatable CPPs (ACPPs), which have displayed the exciting strength in balancing the CPPs' pros and cons, and potential in the treatment and diagnosis of some diseases.
Subject(s)
Humans , Cell-Penetrating Peptides , Chemistry , Drug Delivery Systems , Enzymes , Chemistry , Neoplasms , Drug TherapyABSTRACT
This paper reported that a new type of floating osmotic pump of ambroxol hydrochloride was designed. Third method apparatus (Chinese Pharmacopeia 2010, appendix XD) was employed to simultaneously evaluate the release and floating behavior in vitro. The system was optimized using central composite design-response surface methodology. Similar factor (f2) between the release profile of self-made formulation and the target release profile was chosen as dependent factor. The amount of glucose (A, mg), pore former (B, %) and weight of coating (C, %) were employed as independent factors. Optimized formulation was: A (100.99 mg), B (1.70%), C (4.21%). The value of f2 (89.14) was higher than that of market capsules (69.02) and self-made tablets (72.15). It was showed that self-made capsules possessed character of zero-order release (r = 0.994 4) and drug release completely (>90%). It was showed in result of in vivo study that tmax and Cmax of self-made capsules were significantly lower than that of market capsules and self-made tablets. The correlation coefficient between the fraction of absorption in vivo and the release rate in vitro was 0.985 1, and relative bioequivalence of self-made capsules was 110.77%. Accordingly, self-made capsules displayed obviously characteristics of controlled release both in vivo and in vitro.