[The effect of lipophilic emulsifiers on the drug delivery of salves. 1. Consistency characteristics of salves: drug delivery in vitro].
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Benzocaine↗
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Results for “drug delivery”
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Placebo granules as cores for timed release drug delivery systems.
A drug delivery system is proposed constituted of spherical placebo granules as cores with polymeric surface films containing drug. This timed release dosage form has been prepared by means of a fluidized bed coating technique using ethyl cellulose as the polymeric film and caffeine and salicylic acid as model drugs. The release of the drugs from the dosage form (a) at different drug concentrations and (b) into solutions of different pH showed that drug release was linearly related to the square root of time. Good agreement was found between the theoretical release rate of caffeine, calculated according to Higuchi's equation for a homogenous matrix using membrane permeation parameters measured on linear films, and the experimental results in the case of low drug concentrations. Deviation of the release rate from the homogenous model at high drug concentrations could be explained by crystallization of the drug from the film.
Caffeine↗
Engineering strategies and translational progress in targeted nanoparticle drug delivery.
INTRODUCTION: Nanoparticle-based drug delivery has emerged as a transformative approach in modern therapeutics, offering improved targeting efficiency, enhanced pharmacokinetics, and reduced systemic toxicity compared to conventional drug delivery systems. AREAS COVERED: This review comprehensively examines major nanocarrier platforms, including lipid-based, polymeric, inorganic, and hybrid systems, with emphasis on their structural design and functional properties. It further explores current advancements in targeting strategies, including passive targeting via the enhanced permeability and retention (EPR) effect and active targeting through ligand-receptor interactions involving antibodies, peptides, aptamers, and small molecules. Key biological and technological barriers to clinical translation are also discussed, such as tumor heterogeneity, abnormal vasculature, dense extracellular matrix, immune clearance, and limited cellular uptake. Additionally, emerging stimuli-responsive systems, including pH-, redox-, and enzyme-sensitive nanocarriers, are highlighted for their role in controlled and site-specific drug release. EXPERT OPINION/COMMENTARY: Despite significant progress, the clinical translation of nanomedicine remains constrained by biological complexities and scalability challenges. Future advancements integrating biomimetic strategies, multifunctional design, and artificial intelligence-driven modeling are expected to enhance targeting precision, biocompatibility, and translational success.
Humans↗
Pharmacy, pharmaceutics and modern drug delivery.
Recent developments in the area of drug delivery are reviewed. Controlled delivery of drug substances (including controlled-release oral products, the Folkman-Long silastic device and membrane-medicated delivery systems) are discussed. The prodrug approach is illustrated by discussion of the esterification of epinephrine and the production of the dihydro form of 2-PAM (pro-2-PAM). It is suggested that the pharmacist study the release pattern of drug devices and the pharmaceutics of prodrugs in order to maintain his responsibility as the expert on drugs.
Chemistry, Pharmaceutical↗
The implantable infusion pump: a new concept in drug delivery.
Several of our most useful drugs cannot be administered orally. This paper is a summary of our work with a new drug delivery system: a totally implantable, continuous infusion pump, with a self-contained inexhaustible power source. Currently, after bench tests and animal experimentation, we have initiated clinical series utilizing this device to treat individuals with refractory thromboembolic conditions by intravenous heparin, and patients with localized solid tumors by intra-arterial chemotherapy. The use of this device for the infusion of insulin in the management of diabetes mellitus is yet in the laboratory stage of development. In addition to improving dy-today diabetic control and obviating the need for daily insulin injections, this pump offers an ideal opportunity to test whether optimal blood glucose control can significantly prevent or delay the onset of the crippling vascular complications of diabetes. The potential uses of this device, in many fields, are myriad.
Adult↗
pH-Dependent Surface Charge Modulation of Peptide-Coated Poly(lactic-co-glycolic Acid) (PLGA) Nanoparticle for Drug Delivery in Ovarian Cancer.
The development of nanoparticle (NP)-based drug delivery systems that combine passive tumor targeting, physiological stability, and therapeutic efficacy remains a key challenge in cancer nanomedicine. Here, we report a pH-responsive peptide-functionalized poly(lactic-co-glycolic acid) (PLGA) NP system designed for cancer targeting. The PLGA core is coated with a short glutamic acid-lysine-histidine-phenylalanine x3 (EKHFFF) peptide shell, enabling tunable surface charge modulation around its isoelectric point and promoting environmental responsiveness. Physicochemical characterization confirms spherical NPs (~70-75 nm) with good colloidal stability, serum compatibility, and ion-dependent stability in physiological conditions. The peptide coating also provides pH-dependent modulation of the zeta potential. Evaluation of the NPs in ovarian cancer (OvCA) models, including immortalized and patient-derived cell lines (PDCLs), demonstrates efficient uptake across OvCA cell lines, with significantly enhanced internalization in PDCLs compared to immortalized cells. The EKHFFF nanoparticle (EKHFFF NP) induced minimal reactive oxygen species and nitric oxide production in macrophages, indicating low immunogenicity and favorable biocompatibility. Upon platinum loading (EKHFFF-Pt NP), the system exhibits potent cytotoxicity in both platinum-sensitive and platinum-resistant OvCA cell lines, outperforming carboplatin and showing comparable or improved efficacy relative to cisplatin in several cell lines. In vivo studies further demonstrate preferential tumor accumulation, sustained intratumoral retention, and measurable systemic circulation with a half-life of approximately 35 min.
Female↗
Analysis of theoretical behavior of a proposed zero-order drug delivery system.
An analysis of the theoretical behavior of a proposed zero-order drug delivery system is presented. Equations describing drug release with time are developed using a physically realistic model. The theory agrees well with experimental data and indicates that drug release from the device is nearly, although not rigorously, zero order.
Delayed-Action Preparations↗
Zero-order drug delivery system: theory and preliminary testing.
A new approach to zero-order drug delivery that includes geometric factors is described. An experimental device based on the theory was tested by following the release of stearic acid into ethanol. Three separate trials indicated that the solid was released via a zero-order process in a reproducible manner.
Delayed-Action Preparations↗
Dosage form index: an objective criterion for evaluation of controlled-release drug delivery systems.
A dimensionless parameter, the dosage form index (DLtau) is proposed for evaluating the performance of drug delivery systems. The index is defined as the ratio of the maximum to minimum concentrations of the drug in plasma within each interdose interval (in hours), tau, during repetitive administration of the dosage form in the quasisteady state. Dosage form indexes can be averaged among subjects or within subjects at successive time periods to arrive at a mean value. As an example, two GI therapeutic systems--the 15- and 20-mg/hr acetazolamide systems that deliver drug at constant rates for 6 and 12 hr and contain 125 and 250 mg, respectively--were compared in normal subjects with a commercial sustained-release product containing 500 mg of acetazolamide. The dosage form index, DI24, was 4.9 for the sustained-release dosage form and 3.2 for the 20-mg/hr system; DI12 was 1.6 for the 15-mg/hr system.
Acetazolamide↗
Combinatorial approaches for the identification of brain drug delivery targets.
The blood-brain barrier (BBB) represents a large obstacle for the treatment of central nervous system diseases. Targeting endogenous nutrient transporters that transcytose the BBB is one promising approach to selectively and noninvasively deliver a drug payload to the brain. The main limitations of the currently employed transcytosing receptors are their ubiquitous expression in the peripheral vasculature and the inherent low levels of transcytosis mediated by such systems. In this review, approaches designed to increase the repertoire of transcytosing receptors which can be targeted for the purpose of drug delivery are discussed. In particular, combinatorial protein libraries can be screened on BBB cells in vitro or in vivo to isolate targeting peptides or antibodies that can trigger transcytosis. Once these targeting reagents are discovered, the cognate BBB transcytosis system can be identified using techniques such as expression cloning or immunoprecipitation coupled with mass spectrometry. Continued technological advances in BBB genomics and proteomics, membrane protein manipulation, and in vitro BBB technology promise to further advance the capability to identify and optimize peptides and antibodies capable of mediating drug transport across the BBB.
Animals↗
Sustained drug delivery systems. I. The permeability of poly(epsilon-caprolactone), poly(DL-lactic acid), and their copolymers.
The maximum steady state flux, diffusion coefficients, and solubilities of five contraceptive steroids in homopolymers and copolymers of epsilon-caprolactone and DL-lactic acid were determined. The permeabilities of polymers of epsilon-caprolactone were comparable to silicone rubber and, by inference, are suitable for the construction of drug delivery devices. Poly(DL-lactic acid) was 10(4) times less permeable, although its permeability was significantly enhanced by additives.
Delayed-Action Preparations↗
Testing of drug delivery systems for use in the treatment of narcotic addiction.
The evaluation of the drug release characteristic of four naltrexone delivery systems has been carried out together with the development of analytical techniques and an investigation of the metabolic profile of naltrexone. Pharmacologic evaluation of the four delivery systems in the mouse indicated significant analgesic antagonism for a period of from 16-22 days. Further evaluation of one of these systems by measurement of the rate of excretion of radioactivity after administration of radiolabelled naltrexone in the delivery system confirmed that significant release occurs for a time period of about 15 days. Electron capture gas-liquid chromatographic assays for naltrexone and naloxone in plasma or urine have been developed that yield linear calibration curves and are sensitive to one ng/ml. Studies on naltrexone disposition indicate that (a) binding to plasma proteins in several species varies from 20-26%, (b) distribution of drug from blood is extremely rapid and extensive, (c) beta-naltrexol is a major metabolite of naltrexone in man, monkey and guinea pig among six species studies, whereas alpha-naltrexol is a minor metabolite in the monkey and guinea pig only, and (d) metabolic reduction of naltrexone occurs in the 100,000 x g supernatant of guinea pig liver. Pharmacokinetic studies of naltrexone in the dog and monkey indicate that the drug is rapidly distributed and eliminated, has a very large apparent volume of distribution and a total body clearance greater than the rate of liver blood flow.
Animals↗
Testing of drug delivery systems for use in the treatment of narcotic addiction.
The evaluation of the drug release characteristic of four naltrexone delivery systems has been carried out together with the development of analytical techniques and an investigation of the metabolic profile of naltrexone. Pharmacologic evaluation of the four delivery systems in the mouse indicated significant analgesic antagonism for a period of from 16-22 days. Further evaluation of one of these systems by measurement of the rate of excretion of radioactivity after administration of radiolabelled naltrexone in the delivery system confirmed that significant release occurs for a time period of about 15 days. Electron capture gas-liquid chromatographic assays for naltrexone and naloxone in plasma or urine have been developed that yield linear calibration curves and are sensitive to one ng/ml. Studies on naltrexone disposition indicate that (a) binding to plasma proteins in several species varies from 20-26 per cent, (b) distribution of drug from blood is extremely rapid and extensive, (c) beta-naltrexol is a major metabolite of naltrexone in man, monkey and guinea pig among six species studied, whereas alpha-naltrexol is a minor metabolite in the monkey and guinea pig only, and (d) metabolic reduction of naltrexone occurs in the 100,000 x g supernatant of guinea pig liver. Pharmacokinetic studies of naltrexone in the dog and monkey indicate that the drug is rapidly distributed and eliminated, has a very large apparent volume of distribution and a total body clearance greater than the rate of liver blood flow.
Animals↗
Drug delivery.
The calculations necessary to allow infusion of a known drug dosage at micrograms per kilogram of body weight per minute are time-consuming and error prone. A simpler method entails multiplication of the patient's weight in kilograms by the factor 15. The resultant figure represents the number of milligrams of drug to be placed in 250 ml of infusate vehicle. The solution, which is delivered through a microdrip chamber (60 gtt per milliliter), will contain 1 microgram per kilogram in each drop. One is thus permitted to define dosage by setting up the solution to have 1 gtt = 1 microgram/kg.
Body Weight↗
Continuous drug delivery methods reflect progress in therapy for chronic diseases.
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Aged↗
Implantable drug-delivery systems.
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Animals↗
A new biocompatible drug delivery system for chronic implantation in animal brain.
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Animals↗
Pharmacokinetic evidence for improved ophthalmic drug delivery by reduction of instilled volume.
The bioavailability of topically applied pilocarpine nitrate was studied as a function of instilled volume. As the instilled volume decreased, the fraction of dose absorbed increased. The relationship between fraction absorbed and instilled volume was not direct, but appropriate adjustment of instilled volume and concentration should permit substantial dosage reductions without sacrifice of drug concentration in the eye. The implications of these findings from both a therapeutic and toxicity standpoint are discussed.
Animals↗