Ophthalmic agent preparation viscosity measurement
An ophthalmic preparation refers to a sterile preparation that is directly used for the therapeutic action of the eye. Mainly for topical treatment, mydriasis, miosis, reduce intraocular pressure, anti-infection. Ophthalmic preparations can be classified into ophthalmic liquid preparations (eye drops, eye washes, intraocular injection solutions, etc.), ophthalmic semisolid preparations (eye ointments, ophthalmic creams, ophthalmic gels, etc.) according to the physical form of the preparation. ), ophthalmic preparations solid (Mask, eye pill, intraocular insert, and the like). Ophthalmic liquid preparations may also be packaged in solid form with a solvent and formulated as a solution or suspension prior to use. 02  The significance of viscosity measurement and rheological study 2015  The fourth part of the Chinese Pharmacopoeia contains the viscosity measurement method: the representation of viscosity is mainly  3  Kind of sport Viscosity, intrinsic viscosity and dynamic viscosity, correspondingly  3  a viscometer to test, in which the dynamic viscosity is tested Rotating viscometer. There are many types of rotary viscometers, including coaxial double barrel rotary viscometer, single cylinder rotary viscometer, cone - plate Viscometer, rotor type rotary viscometer, you can choose different types of viscometer according to actual needs. Compared with injection, ocular administration is more convenient, simple, economical, easy for patients to accept, and drugs absorbed by the eye can avoid liver The first pass effect. Compared with other tissues, ocular tissue is not sensitive to immune response and is suitable for drugs such as proteins and peptides. The absorption of these drugs is often not obvious for oral absorption. However, there are some drawbacks to the use of ophthalmic preparations: Small eye volume (in microliters), resulting in less dose; The dilution of the drug by tears will affect the efficacy; The short stay of the drug in the eye will also affect the efficacy. In the development and production of ophthalmic preparations, by adding appropriate pharmaceutical excipients (viscosity regulators) or adjusting internal groups The ratio and composition of the ingredients change the viscosity and rheological properties of the preparation, which can effectively prolong the residence time of the drug on the surface of the eyeball. Increase the release of drug in the eye. It is often desirable to minimize the amount of polymer in the formulation while achieving the desired viscosity and enhancing the efficacy. on the one hand It can reduce the cost of materials, on the other hand, it can reduce the accumulation of polymer in the body and increase the safety of medication. Research and practice It has been found that the combination of some polymers produces a significant synergistic effect on the viscosity of the solution, minimizing the formulation design. The idea of ​​a total amount of polymer is possible. Such as early  PVP  The usual concentration of eye drops is  2.00% , later the United States  Ross Developed by the company  Murine  Tear  Improved to  0.6%  Polyvinylpyrrolidone and  0.5%  Polyvinyl alcohol is mainly The effect of the composition, while maintaining the viscosity, greatly reducing the amount of polymer. 03  Viscosity and rheology of ophthalmic preparations The value of ophthalmic preparations is generally high, and the products are not easily obtained in large quantities, so  AMETEK  -  Brookfield  Suggestion use  Wells  Cone and plate viscometer + TC  Series circulating water bath system (as shown  1  Shown), the ophthalmic formulation viscosity test was performed. The cone and plate viscometer is suitable for the viscosity test of a small sample. The sample volume required for the test is only  0.5-2.0  mL (specific sample The amount is related to the type of rotor used), which can effectively save the test cost; the cone and plate viscometer uses a conical rotor and matching samples. The cup can calculate the exact shear rate and shear stress to get the absolute viscosity; built in the sample cup  RTD  Temperature probe, Through the external circulating water bath, the temperature and temperature of the sample can be controlled and measured during the test; due to the small amount of sample, it can be fast and constant. Temperature, effectively improve test efficiency. TC  Precision temperature control system of circulating water bath zui series high up  0.01 ° C for viscosity testing For accurate and stable temperature conditions. Simple analysis. TC-650  AP  An external circulating water bath is used to control the temperature of the sample.  Rheocalc  T  Software editing test The program collects test data. Test data as shown  2  As shown: the viscosity of the sample shows a decreasing trend as the shear rate increases. The shear stress is nonlinearly related to the shear rate, and it is judged that the sample belongs to a non-Newtonian fluid and has shear thinning characteristics. Sex. For non-Newtonian fluid viscosity testing, the proper rotor and speed (or shear rate) should be chosen to provide greater torque  10% (Medium and high torque is better). In addition, must be under the same test conditions (viscometer model, rotor number, speed, temperature, Test time, sample container, sample size, etc.) for data comparison. In the field of pharmacy, rheological research has important practical applications. Not only the prescription design and production process of pharmaceutical preparations, Storage, transportation, safety and effectiveness are also of great importance for the quality control and application characteristics of pharmaceutical preparations. example If used  RST  Rheometer  3  Shown: Good ophthalmic suspension should be higher under storage (low shear) conditions Viscosity to ensure the stability of the suspension; in use (high shear) should have a lower viscosity, easy to use the drug and Coating. The ophthalmic gel should have a certain thixotropy. When it is dropped into the eye, it will be condensed with the rapid shear caused by eye movement. The viscosity of the gel is rapidly reduced, which is beneficial to the coating of the preparation on the surface of the eyeball; when the eyelid stops twitching, the shear is reduced, and the gel is reduced. The viscosity is quickly restored to ensure the residence time on the surface of the eyeball and increase the release of the drug in the eye. But the gel after the recovery The degree should not be too large, so as not to cause damage to the cornea and increase the discomfort of the eye. 04  Application overview As one of the world's leading zui viscometer / rheometer producers, AMETEK  -  Brookfield  Always committed to the majority The user provides products with stable and reliable quality, high measurement accuracy and good measurement repeatability. Brookfield  Viscometer measurement The accuracy can reach ±1% of the full-scale measurement range , and the repeatability can reach ±0.2% . It is the quality control of the laboratory. Ideal for product development. Personalized solutions for viscosity testing needs in different industries, perfect for each Analysis needs of industry users. RST  The rheometer is capable of comprehensive rheology testing and provides perfect rheological analysis in both quality control and R&D. RST  The series of rheometers have two modes of controlling shear rate and shear stress, and are especially suitable for measuring the steady flow of non-Newtonian fluids. Characteristics such as viscosity and rheological curve. In addition, it can measure viscoelasticity in unsteady shear flow and creep conditions, Yield stress and rheological properties such as thixotropy. Potassium Chloride,Magnesium Chloride Hexahydrate,Calcium Chloride Granules,Calcium Chloride Dihydrate Wuxi Yangshan Biochemical Co.,Ltd. , https://www.salesacetates.com
Ophthalmic preparation
use  DV2TLV  Viscosity measurement and rheological properties of a clinically used eye drop for postoperative disinfection 
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