Controlled Release Drug Delivery System Research Articles

Controlled release of vitamin A palmitate from crosslinked cyclodextrin organic framework for dry eye disease therapy

Controlled release drug delivery systems of eye drops are a promising ophthalmic therapy with advantages of good patient compliance and low irritation. However, the lack of a suitable drug carrier for ophthalmic use limits the development of the aforementioned system. Herein, the crosslinked cyclodextrin organic framework (COF) with a cubic porous structure and a uniform particle size was synthesized and applied to solidify vitamin A palmitate (VAP) by using the solvent-free method. The VAP@COF suspension eye drops were formulated by screening co-solvents, suspending agents, and stabilizing agents to achieve a homogeneous state and improve stability. According to the in vitro release study, the VAP@COF suspension exhibited a controlled release of VAP within 12 h. Both the ex vivo corneal contact angle and in vivo fluorescence tracking indicated that the VAP@COF suspension prolonged the VAP residence time on the ocular surface. This suspension accelerated the recovery of the dry eye disease (DED) model in New Zealand rabbits. Furthermore, the suspension was non-cytotoxic to human corneal epithelial cells and non-irritation to rabbit eyes. In summary, the particulate COF is an eye-acceptable novel carrier that sustains release and prolongs the VAP residence time on the ocular surface for DED treatment

Advancements in microsponges for the management of vaginal and colorectal diseases: A comprehensive review

The controlled-release drug delivery systems have risen dramatically allowing various factors such as the prohibitive cost of developing new entities, the expiration of existing international patents, and the discovery of new polymeric materials suitable for prolonged drug release and improvement in therapeutic efficacy. Microsponges are the porous microspheres-based polymeric delivery system that allows controlled drug release at a specific site. Microsponges are developed for the efficient delivery of active ingredients at a low dose. They help in improving stability by modifying drug release kinetics, reducing side effects, and enhancing the retention of drug entities. Microsponge compositions are stable throughout a wide pH and temperature range, making them more compatible with numerous vehicles, and ingredients. Several studies have shown that microsponges are non-irritant, non-toxic, non-mutagenic, and non-allergic with self-sterilizing properties. They are typically used for topical administration but have lately been used for oral, vaginal, and colorectal administration as well. The current review contains basic information about microsponges, their method of preparation, and various characterization parameters. The review also discusses the application of microsponges in vaginal and colorectal diseases. The latter portion of the script includes various patents and preclinical trials.

A Review of Recent Advancements in Nanotechnology for Medical Drugs Delivery

In recent years, nanotechnology has played a crucial role in revolutionizing the delivery of drugs by allowing precise control of the release and targeting of the drugs. During this review, we will discuss some of the recent advances in nanotechnology for drug delivery systems, as well as strategies used for delivering targeted drugs, controlled release mechanisms, as well as the potential applications of nanotechnology for specific diseases. Among the strategies discussed for targeting drug delivery are ligand-targeted nanoparticles, size-dependent nanoparticles, magnetic nanoparticles, pH-responsive nanoparticles, antibody-targeted nanoparticles, active targeting using peptides that penetrate cells, and surface charge-based strategies. In addition to degradation-controlled release mechanisms, diffusion-controlled release mechanisms are also used as well as pH-controlled release mechanisms, magnetism-controlled release mechanisms, light-controlled release mechanisms, and temperature-controlled release mechanisms. The discussion also includes nanotechnology's potential to treat diseases, including cancer, heart disease, and neurological disorders. This is in addition to its potential applications in general. In order to improve patient outcomes, these advances in nanotechnology have the potential to revolutionize medicine in order to provide targeted and controlled release drug delivery systems that can revolutionize the way medicines are delivered to patients.

Multifunctional organohydrogels for on-demand controlled drug release

Controlled drug release has sparked much attention in the field of drug delivery by prolonging the duration of drug effectiveness and reducing drug toxicity. However, the development of controlled-release drug delivery systems remains a significant challenge, primarily due to inadequate drug compatibility, low biocompatibility, and low response sensitivity of the drug carriers. Herein, an innovative strategy for fabricating multifunctional organohydrogels as drug carrier systems is designed. 1-Tetradecanol/water emulsions, stabilized by cellulose acetoacetate (CAA), are initially prepared. The organohydrogels are fabricated by the ternary enzyme-mediated polymerization of the monomer- containing emulsion. The amphipathy of CAA ensures the stability of emulsions during polymerization, and CAA participates in polymerization as an initiator. Through the reversible crystallization-melting transition of 1-tetradecanol, the drug can be encapsulated in/released from the organohydrogel. Moreover, 1-tetradecanol enhances the bioavailability of water-insoluble drugs without any additional cosolvent. Therefore, biofriendly organohydrogels can serve as ideal dressings with adjustable mechanical properties, effective temperature regulation, and temperature-triggered drug release ability.

A Perspective on Various Facets of Nanoemulsions and its Commercial Utilities.

Nanotechnology is a captivating contemporary technology owing to its extensive range of potential applications. This study emphasizes nanomaterials, substances with a size <100 nm, offering better qualities than coarse particles. Nanoparticles have several advantages compared with conventional drug delivery methods, including enhanced bioavailability and a larger surface area because of their smaller particle size. These characteristics make the nanoparticles a viable clinical candidate. Controlled-release drug delivery systems and targeted drug delivery systems rely heavily on nanoparticles. Because traditional drug delivery methods fail to achieve targeted drug delivery, resulting in toxicity, low bioavailability, poor therapeutic outcomes, and so on, these drug nanoparticles excel in all these areas. Researchers are already interested in developing drug delivery systems such as niosomes, bilosomes, and dendrimers. Nanoemulsion is one of these technologies; nanoemulsions outperform traditional emulsions in terms of pharmacodynamics and pharmacokinetics. Nanoemulsion effectively surpasses the constraints of standard emulsions, primarily by offering enhanced bioavailability, reduced toxicity, improved absorption, and the potential to be used in targeted drug delivery or controlled-release drug delivery systems. This particular work explores several aspects of nanoemulsions, including their constituents, classification, techniques for preparation, criteria for assessment, commercial applications, and future prospects.

Doxorubicin loaded octacalcium phosphate particles as controlled release drug delivery systems: Physico-chemical characterization, in vitro drug release and evaluation of cell death pathway

Mastering new and efficient ways to obtain successful drug delivery systems (DDS) with controlled release became a paramount quest in the scientific community. Increase of malignant bone tumors and the necessity to optimize an approach of localized drug delivery require research to be even more intensified. Octacalcium phosphate (OCP), with a number of advantages over current counterparts is extensively used in bone engineering. The aim of the present research was to synthesize bioactive and biocompatible doxorubicin (DOX) containing OCP particles. DOX-OCP was successfully obtained in situ in an exhaustive range of added drug (1–20 wt%, theoretical loading). Based on XRD, above 10 wt% of DOX, OCP formation was inhibited and the obtained product was low crystalline α-TCP. In-vitro drug release was performed in pH 7.4 and 6.0. In both pH environments DOX had a continuous release over six weeks. However, the initial drug burst for pH 7.4, in the first 24 h, ranged from 15.9 ± 1.3 % to 33.5 ± 12 % and for pH 6.0 23.7 ± 1.5 % to 36.2 ± 12 %.The DOX-OCP exhibited an inhibitory effect on viability of osteosarcoma cell lines MG63, U2OS and HOS. In contrast, MC3T3-E1 cells (IC50 > 0.062 µM) displayed increased viability and proliferation from 3rd to 7th day. Testing of the DDS on ferroptotic markers (CHAC1, ACSL4 and PTGS2) showed that OCP-DOX does not induce ferroptotic cell death. Moreover, the evaluation of protein levels of cleaved PARP, by western blotting analysis, corroborated that apoptosis is the main pathway of programmed cell death in osteosarcoma cells induced by DOX-OCP.

Chitosan-Grafted-Poly(N-vinylcaprolactam)-Decorated Fe3O4@SiO2 Core-Shell Nanoformulation as an Efficient Drug Delivery System for Poorly Soluble Drugs.

Hydrocortisone, a commonly used anti-inflammatory drug, has limited aqueous solubility and several side effects. To address this challenge, as a proof-of-concept, this article demonstrates the development of a controlled-release drug delivery system (DDS) for hydrocortisone using chitosan-grafted poly(N-vinylcaprolactam) (CS-g-PNVCL)-coated core-shell Fe3O4@SiO2 nanoformulations (NFs). Reported magnetic nanoparticles (NPs) were synthesized and modified with silica, PNVCL, and CS precursors to enhance the biocompatibility of DDS and drug-loading efficiency. The release rate of hydrocortisone from Fe3O4@SiO2@CS-g-PNVCL NFs was observed to be higher at lower pH values, and the smart polymer coating demonstrated temperature responsiveness, facilitating drug release at higher temperatures. Fe3O4@SiO2@CS-g-PNVCL NFs exhibited a cell viability of around 97.2 to 87.3% (5-100 μg/mL) after 24-48 h, while the hydrocortisone-NFs had a cell viability of around 93.2 to 82.3%. Our findings suggest that CS-g-PNVCL-coated Fe3O4@SiO2 NPs effectively enhance the solubility, loading capacity, and targeted delivery of poorly soluble drugs, thereby improving their therapeutic efficacy and bioavailability.

Zeolitic imidazole framework-8 loaded gelatin methacryloyl microneedles: A transdural and controlled-release drug delivery system attenuates neuroinflammation after spinal cord injury

Spinal cord injury (SCI) is a matter of significant clinical concern, often treated through early surgical decompression along with methylprednisolone sodium succinate (MPSS). However, the side effects and the unsatisfactory focal concentration of MPSS have limited its further applications. To address this limitation, herein, a versatile drug delivery system of zeolitic imidazole framework-8 (ZIF-8) and gelatin methacryloyl microneedles (GelMA MNs) was developed for stable, transdural, and controlled sustained release of drugs in SCI. The microneedles were used to create tiny pores in the dura mater, allowing for the direct administration of drugs into the spinal cord. ZIF-8 provided a secondary extended release once they were separated from the microneedles. To attenuate the neuroinflammation, MPSS was selected. Such a combination of ZIF-8 and GelMA MNs was able to prolong the release period of MPSS to five days. The system showed transdural capacity, reduction of M1 polarization, and decrease in NLRP3-positive inflammasome and proinflammatory cytokines. In vivo studies indicated that this novel drug delivery strategy could constrict the inflammatory microenvironment, reduce glial scar formation, and promote neural regeneration. Thus, this versatile drug delivery system provides an up-and-coming alternative for stable, transdural, and controlled sustained release of drugs to those suffering from SCI.

An Overview on IPN and its Medicinal applications

Interpenetrating polymer network (IPN) is regarded as one of the most useful novel biomaterial. The invention of IPN can be rendered biocompatible and biodegradable has far reaching and profound long‐term implications for the pharmaceutical industry and indeed medicine as a whole. The excellent biocompatibility and safety due to its physical characteristics such as impart stability of the drug in the formulations, improves solubility of hydrophobic drugs, excellent swelling capacity and its biological characteristics, like biodegradability, impart bioavailability, drug targeting in a specific tissue and very weak antigenicity, made IPN the primary resource in both pharmaceutical and medical applications IPNs, two or more networks are at least partially interlaced on a polymer scale. Base on applications, polymers and polymer networks needs to have certain properties. IPNs can be used with interpenetration of suitable polymers to have desired properties for specific applications. The potential applications of IPN as drug delivery systems specially for the controlled release drug delivery systems. It was also used for tissue engineering including bone substitutes, stationary phase and cartilage scaffolds These systems which are also termed as ‘hungry networks’ or ‘intelligent polymers’ are currently the focus of considerable scientific research due to their potential technological application in a large number of areas: medicine, industry, biology and environmental clean-up. Some of the significant applications of IPNs include artificial implants, dialysis membranes, drug-delivery systems, burn-dressings, etc Interpenetrating polymer network has scope for its use as carrier system in drug delivery system. Characteristics of rubber can be modified by using different reinforcements.

Synthesis and Characterization of Novel pH-Responsive Aminated Alginate Derivatives Hydrogels for Tissue Engineering and Drug Delivery.

The aims of this study are to synthesize new derivatives of sodium alginate that improve the inherent properties, such as hydrogel strengthening, and create environmental sensitivity, such as pH sensitivity, for use in drug delivery. Today, hydrogels, due to outstanding properties such as biodegradability, biocompatibility, mechanical properties, and response to stimuli properties, are widely used as harmless biomaterials in various fields in drug delivery, wound dressing, and tissue engineering. Stimulus-sensitive polymers significantly respond to slight changes in their environment. Different types of stimuli are used to influence the properties of polymers, the most important of which are temperature and pH because these are two vital factors in the human body; hence, temperature-sensitive and pHsensitive hydrogels have been extensively studied. The ability to absorb water and swell the hydrogel is due to hydrophilic chains in the hydrogel network, and water absorption by hydrogel can be controlled by response to the stimuli. Since hydrogels mimic human tissue, the ability to retain water in them is essential. As a result, it is considered in many biomedical drug delivery systems. Stimulusresponsive swelling can control diffusion out of and into the hydrogel network, which allows temporal and spatial control of drug release. When a drug is loaded onto a biodegradable and stimulisensitive hydrogel, the drug delivery system has the added advantage of sustained release of the drug, which reduces side effects. In this study, two different hydrocarbons, [1,3-diaminopropane (DAP)] as a short-chain hydrocarbon, and [1,7-diaminoheptane (DAH)] as a long-chain hydrocarbon were grafted onto three types ofsodium alginate (SA), through amide bond linkages. The hydrogel copolymer matrices were compared with sodium alginate (SA) beads. The graft copolymers were characterized using FTIR, 1HNMR, XRD spectroscopy, elemental analysis (CHNS) and thermal analysis (TGA, DTA and DSC). An environmental scanning electron microscope (ESEM) was used to investigate the surface morphology of hydrogels. Effects of variables such as the length of hydrocarbon chains cross-linked to alginate, temperature, pH, and cross-linkers on the properties of hydrogels investigated in the temperature range of 2-70 ˚C and two different pH values (4.4 and 7.4). The results showed that when the hydrocarbon chain length of diamines decreases, the extent of cross-linking and strength of the hydrogels are increased. Other results suggest that the hydrogels obtained from high-viscosity alginate derivatives had positive pH sensitivity. Hydrogels prepared in this study demonstrated good mechanical and swelling ratios that are necessary for wound dressing. DAP-g-SA and DAH-g-SA pH-sensitive hydrogels were successfully synthesized through amide bond linkages. The new synthesis derivatives showed lower swelling levels at low pH (4.4). In contrast, their swelling levels at higher pH (7.4) were significantly enhanced. Higher swelling degree could be obtained at high pH. pH-responsive hydrogels are especially useful for various biological applications due to their unique feature of controlled swelling, biodegradability, biocompatibility, and fluid retention in their network structures. pH-responsive hydrogels, as intelligent systems, can be used in controlled-release drug delivery systems such as insulin delivery.

Prolonged Anesthesia Effects of Locally Administered Ropivacaine via Electrospun Poly(caprolactone) Fibrous Membranes.

Prolonged analgesia is important to safeguard the patient's comfort and safety during and after surgery in clinical practice. To meet the demand for prolonged analgesia, medical professionals often resort to increasing drug frequency, which may lead to poor patient compliance and serious complications due to drug overdose. Therefore, it is of great interest to develop controlled-release drug delivery systems for local anesthetics, enabling slow and controlled drug release to prolong the analgesic effect and minimize systemic toxicity. In this study, we utilized an electrospinning technique to fabricate nonwoven poly(caprolactone) (PCL) fibrous membranes loaded with Ropivacaine and performed proof-of-principle experiments on both in vitro drug release tests and in vivo animal tests, to further prolong the analgesic effect of Ropivacaine and improve postoperative local pain management and chronic pain treatment. Material characterization and in vitro drug release studies confirmed the feasibility of the Ropivacaine-loaded PCL fibrous membranes for sustained release. The drug loading content and drug loading efficiency of Ropivacaine-loaded fibrous membrane are 8.7 ± 0.3 wt% and 96 ± 3 wt%, respectively. Evaluation in an animal model demonstrated prolonged anesthesia effects along with excellent biocompatibility and stability. At 72 h, the cumulative release accounted for approximately 50% of the drug loading content. This study offers novel approaches and strategies for clinical postoperative pain management and chronic pain treatment, while providing new insights and directions for the design of local anesthetic controlled-release delivery systems.

CO2-Driven Nebulization of pH-Sensitive Supramolecular Polymers for Intraperitoneal Hydrogel Formation and the Treatment of Peritoneal Metastasis.

Because peritoneal metastasis (PM) from ovarian cancer is characterized by non-specific symptoms, it is often diagnosed at advanced stages. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) can be considered a promising drug delivery method for unresectable PM. Currently, the efficacy of intraperitoneal (IP) drug delivery is limited by the off-label use of IV chemotherapeutic solutions, which are rapidly cleared from the IP cavity. Hence, this research aimed to improve PM treatment by evaluating a nanoparticle-loaded, pH-switchable supramolecular polymer hydrogel as a controlled release drug delivery system that can be IP nebulized. Moreover, a multidirectional nozzle was developed to allow nebulization of viscous materials such as hydrogels and to reach an even IP gel deposition. We demonstrated that acidification of the nebulized hydrogelator solution by carbon dioxide, used to inflate the IP cavity during laparoscopic surgery, stimulated the in situ gelation, which prolonged the IP hydrogel retention. In vitro experiments indicated that paclitaxel nanocrystals were gradually released from the hydrogel depot formed, which sustained the cytotoxicity of the formulation for 10 days. Finally, after aerosolization of this material in a xenograft model of PM, tumor progression could successfully be delayed, while the overall survival time was significantly increased compared to non-treated animals.

Injectable controlled-release systems for the prevention and treatment of infectious diseases.

Pharmaceutical drugs, including vaccines, pre- and post-exposure prophylactics, and chronic drug therapies, are crucial tools in the prevention and treatment of infectious diseases. These drugs have the ability to increase survival and improve patient quality of life; however, infectious diseases still accounted for more than 10.2 million deaths in 2019 before the COVID-19 pandemic. High mortality can be, in part, attributed to challenges in the availability of adequate drugs and vaccines, limited accessibility, poor drug bioavailability, the high cost of some treatments, and low patient adherence. A majority of these factors are logistical rather than technical challenges, providing an opportunity for existing drugs and vaccines to be improved through formulation. Injectable controlled-release drug delivery systems are one class of formulations that have the potential to overcome many of these limitations by releasing their contents in a sustained manner to reduce the need for frequent re-administration and improve clinical outcomes. This review provides an overview of injectable controlled drug delivery platforms, including microparticles, nanoparticles, and injectable gels, detailing recent developments using these systems for single-injection vaccination, long-acting prophylaxis, and sustained-release treatments for infectious disease.

PREPARATION AND EVALUATION OF PROPRANOLOL HCL AND CARBAMAZEPINE RELEASE PROFILES FROM POLY(Є-CAPROLACTONE) MICROPARTICLE BLENDS SYSTEM

Objective: The goal of this research was to look into the physicochemical properties of poly(-caprolactone) microparticle blends that contained medicines of various solubilities (Propranolol HCl [Pro] and carbamazepine [CBZ]). Methods: W/O/W emulsion for Pro and O/W emulsion for CBZ were used to create microparticle blends. With dispersion time intervals (DTI) of 0 and 60 min, the Pro emulsion (W/O) and CBZ oil phase (O) were dispersed in an external aqueous phase (W). Scanning electron microscopy was used to examine the morphology of microparticle blends (SEM). Focused beam reflectance measurements were utilized to monitor the particle size mean of emulsion droplets/hardened microparticles (FBRM). In phosphate buffer (pH 7.4), encapsulation efficiency (EE) and in vitro drug release were also examined. Results: The final microparticle blends generated by solvent evaporation method were spherical and had two populations, according to the findings. The size of microparticle blends prepared with DTI 60 min and stirring duration 4 h was bigger than those prepared with DTI 0 min, according to FBRM data. In microparticle blends, encapsulation efficiency ranged from 62.05±3.74 percent to 66.38±4.16 percent for Pro and 70.56±4.62 percent to 73.85±4.11 percent for CBZ. After 28 d, drug release in phosphate buffer revealed that Pro release (33%) was shorter than CBZ release (60%) from microparticle blends with DTI 60 min. This was related to the interaction of the oil phase (CBZ) with hard particles from the primary emulsion (Pro), in which the oil phase occluded and covered surface structure of the harsh particles from the primary emulsion. Conclusion: Novel microparticle blends comprising drugs/medicines with varying solubilities (e. g. propranolol HCl and carbamazepine) have a lot of promise as controlled-release drug delivery systems. The physical properties of microparticle blends were impacted by the type of dispersion time interval used.

Preparation and Administration of a Controlled-Release Delivery System of Chitosan Hydrogel loaded with Methadone and Piroxicam in Experimental Defect of Tibial in Rats; Histopathological Evaluation

Purpose: In this study, a controlled-release drug delivery system loaded with piroxicam and methadone was synthesized and used subcutaneously in rats with experimental tibial defect, and healing were assessed histopathologically.&#x0D; Materials and Methods: For this purpose, 100 adult female rats were randomly divided into five equal groups; control group, chitosan group, piroxicam group, methadone group, and piroxicam-methadone group. The morphological structure of the synthesized drug systems was studied by scanning electron microscope. In addition, the structure of the hydrogels was investigated by Fourier transform infrared spectroscopy and while releasing the hydrogels' gelation time, the release of piroxicam and methadone from the hydrogels was evaluated in vitro.&#x0D; Results: Histological results of the 3rd day of the study showed the lowest extent and severity of inflammation in the chitosan, piroxicam, and piroxicam-methadone groups, while on the 7th day, tissue inflammation and the extent of bleeding were lower in the piroxicam, methadone, and piroxicam-methadone groups than in the other groups. Evaluation of new bone formation on day 21 showed that the chitosan, piroxicam, and methadone groups had better repair than the other groups.&#x0D; Conclusion: It seems that in the control group that did not receive any treatment intervention, following the experimental bone defect, the highest inflammatory response was observed in histological examination and finally the weakest bone repair. On the other hand, the presence of piroxicam, methadone, and chitosan in the piroxicam-methadone group (all of which have anti-inflammatory effects) also seems to have a negative effect on the repair.

Evaluation of Changes in Antioxidant Factors and Albumin Level Following the Administration of a Controlled-Releasing Drug Delivery System of Chitosan Hydrogel Loaded with Buprenorphine and Ketorolac in an Experimental Bone Defect in the Tibia of the Rat

Full Title: Evaluation of Changes in Antioxidant Factors and Albumin Level Following the Administration of a Controlled-Releasing Drug Delivery System of Chitosan Hydrogel Loaded with Buprenorphine and Ketorolac in an Experimental Bone Defect in the Tibia of the Rat Model &#x0D; Background: In the present study, the effectiveness of a controlled-release drug delivery system of chitosan hydrogel loaded with ketorolac and buprenorphine on oxidative stress indices and albumin changes in the experimental bone defect model was considered.&#x0D; Methods: After creating an experimental defect in the right tibia of each rat, 5 groups, including (A) the control group that did not receive any pharmacological intervention, (B) the chitosan hydrogel receiving group, (C) the group receiving chitosan hydrogel loaded with buprenorphine, (D) the group receiving chitosan hydrogel loaded with ketorolac, and (E) the group receiving chitosan hydrogel loaded with ketorolac and buprenorphine, were considered. Serum concentrations of antioxidant factors and albumin levels were then measured on days 0, 3, 7, and 21 after surgery.&#x0D; Results: In the control group, the maximum amount of oxidative stress and the maximum activity of antioxidant enzymes on the third and seventh days were compared between the 4 treatment groups. Moreover, the maximum amount of albumin on the third day was recorded and compared between the 4 other treatment groups. In 4 treatment groups, a significant decrease was observed in the mean of parameters related to oxidative stress compared to the control group, which was more noticeable in the group receiving ketorolac.&#x0D; Conclusion: In the present study, the highest rate of control of oxidative stress conditions was observed in the group treated with the ketorolac-loaded chitosan hydrogel system, possibly due to its antioxidant properties and better control of inflammatory conditions caused by the use of chitosan and ketorolac in this treatment group.

Trends in Ophthalmological Patents, 2005-2020.

Purpose: Technological development drives the optimization of therapeutics in ophthalmology, but quantifiable and systematic review of such innovation is lacking. To fill this gap, we characterize trends in ophthalmology-related patents in the United States from 2005 to 2020. Methods: Publicly available patent data from the US Patent and Trademark Office was analyzed with the R programming language. Ophthalmology-related patents were identified with a keyword search of their titles and claims text. Temporal trends were assessed with the Mann-Kendall trend test (α = 0.05, two-sided). Results: Of 4.5 million collected patents, some 21,000 (0.5%) were ophthalmology related. The number of annually granted ophthalmology patents increased over time (Mann-Kendall test: z = 4.91; P < 0.001), from 619 patents released in 2005 to 2,019 patents in 2020. Patent counts also increased over time for all ophthalmic subspecialties except oculoplastics, with steepest rises in retina (z = 4.91; P < 0.001) and cornea (z = 4.64; P < 0.001). The most cited patents were in biocompatible intraocular implants and implantable controlled-release drug delivery systems, which underscores particular advancement in therapeutic efficacy and safety in devices used in the treatment and management of common yet debilitating eye conditions. Conclusion: This exploratory analysis reveals hotspots for ophthalmology-related innovation in the United States that may predict current and future growth trends in device development and pharmacologic advancement in ophthalmology, paving the way for more diverse and effective treatment options for preserving vision.

Preparation of pH sensitive bacteriostatic W/O/W emulsion microcapsules

This experiment was done to study the zeolite molecular sieve as a drug-binding effector, the non-antibiotic drug potassium diformate uniformly disperse in the internal aqueous phase of the 'egg box' structure formed by pectin-calcium ions. With oil phase as the intermediate phase and Xanthan gum Chitosan as the external water phase, the W/O/W type sustained release bacteriostatic microcapsules with pH response were prepared and characterized by Fourier transform infrared, thermogravimetric, SEM, and TEM. It can be obtained through characterization experiments that the inner water phase, oil phase, and outer water phase were formed by observation, and W/O/W emulsion microcapsules were obtained and the bacteriostasis effect of microcapsules was verified by bacteriostasis experiment. The permeance experiment showed that the molecular sieve was successfully coated in the microsphere. Studying on drug release mechanism and sustaining release performance of composite emulsion microcapsules. In vitro drug release study showed that the encapsulation efficiency and drug loading rate of microcapsules were improved by adding molecular sieve, reaching 12.31% and 61.55%, respectively. At the same time, we observed that the drug release rate slowed down during the simulated intestinal release process, and the drug release kinetics were in line with the first-order kinetic model and Ritger-Peppas model equation. Experiments had proven that the drug-loaded microcapsules exerted a significant bacteriostatic effect on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis, with the highest antibacterial rates of 97.25%, 94.05%, and 95.93%, respectively. Therefore, the composite emulsion microcapsules can be used as a new controlled-release drug delivery system in vivo.

The role of matrix tablet in controlled release drug delivery system

The purpose of this review article is to characterize all of the parameters regarding the types, polymers used, and release kinetics of matrix tablets. Matrix system was the earliest oral extended-release platform for medicinal use. Matrix tablets are most commonly used methods to modulate the release profile of drugs. They are much desirable and preferred for such therapy because they offer better patient compliance, maintain uniform drug levels, reduce dose and side effects, and increase safety margin for high potency drugs. Hydrophilic polymer matrix systems are widely used for designing oral controlled drug delivery dosage forms because of their flexibility to provide a desirable drug release profile, cost effectiveness, and broad regulatory acceptance. However, the use of hydrophilic matrix alone for extending drug release for highly water-soluble drugs is restricted due to rapid diffusion of the dissolved drug through the hydrophilic gel network. For such drugs it becomes essential to include hydrophobic polymers in the matrix system. This leads to the conclusion that matrix tablets seem to be most promising when developing an oral controlled release formulation.

The role of matrix tablet in controlled release drug delivery system

The role of matrix tablet in controlled release drug delivery system