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OBJECTIVE@#Traditional Chinese medicine (TCM) has been widely used throughout China to prevent and cure diseases for thousands of years, and now it is a part of the integrative medicine field that is available in Western societies. To ensure the safety and quality of the herbal medicines that are a major part of the TCM tradition, they must be held to modern pharmaceutical standards. Erzhi pill (EZP) is a Chinese Pharmacopeia-listed herbal preparation that is used in the long-term clinical management of post-menopausal symptoms, osteoporosis and menstrual disorders. Until now, whether the drug release mechanism of EZP is in line with its intended TCM usage has not been studied.@*METHODS@#The release of specnuezhenide from three EZPs (self-made, Leiyunshang and Renhe) in simulated gastric fluid (SGF), acetate buffer (pH 4.5 buffer) and simulated intestinal fluid (SIF) was investigated in a dissolution test. The water uptake capacity and erosion extent of the three EZPs were investigated using swelling and erosion studies. The drug release mechanism was further assessed through statistical model fitting, using DDSolver software.@*RESULTS@#The release of specnuezhenide from all three EZPs in SGF was less than 50% within a 4 h period. However, over 70% of the specnuezhenide was released from each EZP in both pH 4.5 buffer and SIF in the same time. Analysis of the swelling and erosion behaviors and the drug release mechanism of the three EZPs confirmed that the release rate from EZP followed a sustained release profile, which was an interactive combination of swelling and erosion.@*CONCLUSION@#This study showed that the release pattern from the pills was in line with the intended TCM use of EZP. TCM had not only theoretically considered sustained release from the pills, but also formulated them to achieve this release pattern. When establishing quality control standards for pills, the theoretical TCM usage and the actual release patterns need to be considered.
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Background The time rhythm of human body is associated with the occurrence and development of manydiseases, and it also affects the efficacy and pharmacokinetic characteristics of the corresponding therapeuticdrugs. Therefore, the chronopharmacological drug delivery system has potential applications. Aim In this work, it is proposed to develop a kind of pulsatile release tablet of simple structure and preparingprocess, thus to provide an alternative drug delivery system for therapeutic agents used in treatment of diseasesof typical onset biorhythm at period inconvenient to take drug.Methods Metoprolol tartrate (MT), a drug widely used clinically to treat cardiovascular diseases was selected asa model drug for developing pulsatile tablets of time-controlled explosive system (TES). The MT pulsatile tabletswere ethyl cellulose (EC) coating tablets produced by pan coating process, and the core tablets were preparedby direct compression. The formulation and process was optimized by single factor test and orthogonal design.Also, the pulsatile release mechanism of the tablets was discussed through investigating the water absorptionand swelling capacity of tablets as well as the mechanical properties of EC free film.Results A kind of pulsatile tablets of MT were developed with a drug release lag time around 7 h and a fastrelease of drug after lag time. When the swelling force of core tablet caused by water uptake was high enoughover the tensile strength of EC coating film, the MT pulsatile tablets demonstrated a shell-type exploding rupturedue to the great rigidity and weak flexibility of EC film, and then a fast pulsatile release of drug was observed.Both the swelling capacity of core tablet and the thickness of coating film together controlled the lag time of drugrelease. The lag time showed a good linear relationship with the thickness of coating film (r = 0.9984, P < 0.01).The sort and amount of fillers and disintegrants dominated the release behaviour after lag time.Conclusion The developed MT pulsatile tablets can exert a timely release of drug before peak onset period ofhypertension and angina pectoris early in the morning after drug taking around 22:00 P.M the night before. Thegood linear relationship between lag time and coating thickness enabled the pulsatile tablets to be used fordelivery of other therapeutic agents of similar chronotherapy demand by adjusting the coating thickness toachieve the appropriate lag time of drug release to match the different high attack rhythm of the exact diseases.
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In the present experimental investigation an attempt has been made to assess the utility of Crushed Puffed Rice (CPR)-High Molecular Weight Chitosan (HMWCH)-Hydroxypropyl Methylcellulose K15M (HPMC K15M) as a polymeric carrier for the sustained stomach delivery of Piroxicam (PRX). A total of nine formulations were prepared by using 3 (2) Taguchi factorial design, physically blending drug and polymer(s) followed by encapsulation into hard gelatin capsules size 1. The prepared capsules were evaluated for various performance such as weight variation, drug contents, in vitro buoyancy and drug release in 0.1 M HCl. The effect of drug loading on in vitro performance of the formulations was also determined. Crushed puffed rice (CPR) remained buoyant for up to average time span of 06 hr as an unwetted irregular mass in 0.1 M HCl. However, when combined with HMWCH or HPMC K15M or HPMC K15M + HMWCH a low -density cylindrical raft type hydrogel was formed which remained buoyant for up to 12 hr and released up to 99% drug in a sustained manner from 8 to 12 hr following zero order release kinetics. It was also observed that drug release from drug + CPR matrices followed Fickian mechanism. Combination of CPR + HMWCH or HMWCH + HPMC K15M also follows Fickian mechanism. Obtained data from the research work suggests that CPR in combination with HMWCH or HPMC K15M or HPMC has sufficient potential to be used as a carrier for stomach specific delivery of gastric irritant drug like PRX
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Objective:To prepare febuxostat nanosuspension and prepare sustained-release pellets,and investigate the in vitro dis-solution.Methods: Febuxostat nanosuspension was prepared by a high pressure homogenization method. Febuxostat nanosuspension pellets were prepared by fluidized bed coating technique. Eudragit RL30D and Eudragit RS30D were used to prepare the sustained-re-lease pellets. The dissolution mechanism of febuxostat nanosuspension sustained-release pellets was evaluated. Results: The average particle size of the prepared febuxostat nanosuspension was (212.5 ± 36.3) nm, PdI was (0.193 ± 0.018), zeta potential was ( -12.4 ± 0.3) mV,and the scanning electron microscopy showed that the particle size distribution of febuxostat nanosuspension was narrow. The in vitro dissolution of febuxostat nanosuspension sustained-release pellets was more stable and conformed to the first-order release model. Conclusion: The in vitro dissolution of febuxostat nanosuspension sustained-release pellets is more stable, and the preparation provides a new choice for febuxostat clinical application.
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OBJECTIVE:To optimize the formulation of Cilnidipine sustained-release tablet,and study its drug-release mecha-nism. METHODS:Solvent method was adopted to prepare the cilnidipine solid dispersion,then Cilnidipine sustained-release tablet was prepared by using hypromellose K4M(HPMC K4M)as release material. Using comprehensive scores of cumulative release de-gree in 2,6,12 h as indexes,single factor method and Box-Behnken response surface method were used to screen the amounts of HPMC K4M and ethyl cellulose (EC),lactose-microcrystalline cellulose (MCC) ratio in formulation of Cilnidipine sustained-re-lease tablet,and verification test was conducted. The drug-release mechanism of Cilnidipine sustained-release tablet was investigat-ed by model fitting way. RESULTS:The optimal formulation was as follow as 25％ of cilnidipine solid dispersion,30％ of HPMC K4M,10％ of EC,lactose-MCC ratio of 1:1(m/m). The adhesive was 5％ PVPP ethanol solution and the lubricant was 0.5％magnesium stearate. The cumulative release degrees of prepared sustained-release tablet in 2,6,12 h were(21.4±3.3)％,(62.9± 2.8)％,(85.4±0.5)％(n=3),relative error of which to predicted value 25％,60％,90％were 14.4％,4.8％and 5.1％. Release curve showed the highest fitting degree with the first-order release model,conforming to non-Fick diffusion. CONCLUSIONS:Cil-nidipine sustained-release tablet with sustained-release effect is successfully prepared by optimized formulation.
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Controlling In-vitro drug release profiles for a system of PLGA/PLA microparticles encapsulating a hydrophobic drug. Challenges with the diversity of drug properties, microencapsulation methods, are evaluated with a focus on decreasing the time to lab-scale encapsulation of water-insoluble drug candidates in the drug development stage. The development of biodegradable microparticles systems that combined the beneficial properties of polymeric microparticles for hydrophobic drug delivery were reviewed here. Injectable biodegradable and biocompatible copolymers of lactic and glycolic acid are important advanced delivery system for week too month controlled release of hydrophobic drug (e.g., from biopharmaceutical classification system class IV), which often display poor oral bioavailability. Finally, three important properties affecting release behavior were identified as: polymer hydrophobicity, particle size and particle coating, . This review focuses on the microencapsulation of hydrophobic drugs, describes a variety of techniques for their preparation and analytics.