The fractional dispersed phase hold-up and mass transfer coefficients were measured in modified spray columns of 50 mm i.d. using an aqueous two phase system of polyethylene glycol (PEG 4000)-sodium sulphate-buffer. The mass transfer coefficients were measured for amyloglucosidase and pgalactosidase. Both co-current and countercurrent modes of operation were investigated.The dispersed phase hold-up ( g o ) and the dispersed phase and the continuous phase mass transfer coefficients (kDa, k p ) increased with increasing dispersed phase velocity. An increase in the phase concentration of sodium sulphate and PEG was found to reduce E~, kDa, and k p . The performance of the modified spray column is compared with the conventional spray column. The modifications resulted into about a ten-fold enhancement in the throughput and about a five-fold reduction in the value of the height of a transfer unit (HTU or isolating a desired protein or an enzyme from a com-F plex mixture, the two-phase aqueous extraction technique offers the advantages of gentle environment, favourable processing time and easy scale-up (Albertsson, 1985).Methods of conventional extraction, such as spray columns, can be conveniently applied to aqueous two-phase systems. Spray columns are very popular because of their simple construction and ease of operation. Sawant et al. (1990) In these investigations, the maximum superficial velocity of the dispersed phase was 1.1 d s . Any W e r increase in the dispersed phase velocity led to the formation of a dense uncoalesced layer of drops in the top region of the liquid-liquid dispersion. This eventually resulted in the flooding of the spray column. The maximum permissible dispersed phase velocities are considerably lower than those possible for conventional liquid-liquid extraction systems using spray columns. This has resulted in relatively lower values of the mass transfer coefficient and the effective interfacial area. The HTU values estimated based on these prior results vary in the range of 3 to 5 m. Thus, a typical need of five theoretical stages will require considerably tall spray columns. From the foregoing discussion, it is clear *Author to whom correspondence should be addressed. E-mail address: j bj@udct .erne!. in that conventional spray columns need modification so that higher throughputs are possible and the values of HTU are well under 1 m.In addition to this, the data base with regard to mass transfer coefficients for proteins is limited. Protein molecules have a complex physical structure. Further, in comparison to the conventional solutes, the molar masses of proteins are very large (ranging from few to hundreds of thousands). The problem of mass transfer is further compounded by the higher viscosities of the two phases in aqueous two phase systems.The present paper addresses these problems. The spray column design is modified and the cross sectional area of the column in the coalescence zone is increased substantially to facilitate coalescence, thereby permitting the operation of the sp...
The aim of the present study was to prepare sustained release matrix tablets of lornoxicam to make drug in sustained form so as to prolong its elimination time for the effective treatment of rheumatoid arthritis, and also in the management of ankylosing spondylitis, acute sciatica and low back pain. The present investigation demonstrates that, use of hydrophilic and hydrophobic polymers could be successfully employed for formulating sustained release matrix tablets of Lornoxicam. Optimized formulation containing HPMC K100M and Ethyl cellulose at optimum ratio had successfully sustained the drug release for 24 h. Matrix tablets of optimized batch had in vitro drug release. It was observed that the optimized matrix tablets of optimized batch shows better flow property by studying various pre-compression parameters. Thus, sustained release matrix tablets of Lornoxicam using biocompatible polymers were successfully formulated, evaluated and found to be suitable candidates in extending the release of the drug from the matrix tablets.
Background: Improvement of patient care and safety in relation to the use of medicines with medical and paramedical interventions remains to be an important parameter. Adverse drug reactions have proved a significant problem in healthcare for a decade. The main aim of ADRs monitoring is to the promoting rational use of drugs, safe use of medicines improving patient care, improving public health. Objectives: The study aimed to determine the prevalence of ADRs in a tertiary care hospital to generating data safety of medications. Materials and Methods: The Prospective, observational study was conducted in the wards of a tertiary care Hospital. All patients were monitored for ADRs during their admission period. ADRs are a common occurrence but are often not recognized. Even if recognized, they are underreported as many physicians are unaware that all ADRs should be reported to ADR monitoring centers. Results and Discussion: Over the study period of two years, a total of 325 patients reports were monitored. The ADRs observed were higher in male patients and the highest number of ADRs were reported in the case of Sacubitril/valsartan followed by Amlodipine and in most of the cases drug is withdrawn.
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