PREPARATION AND DRUG RELEASE CHARACTERISTICS OF PINGYANGMYCIN GELATIN MICROSPHERES FOR EMBOLIZATION THERAPY

Objective: To prepare Pingyangmycin gelatin microspheres (PYM-GMS) for carotid artery embolization therapy and to study the release characteristics in vivo and in vitro. Methods: PYM-GMS was prepared by optical double-phase emulsified condensation polymerization. Through UV-spectrophotometer drug content and encapsulation rate were measured. The characteristics of drug release in vitro which could simulate the actual state in vivo were tested by HPLC. Three ways of vein drop, artery perfusion and artery embolization were contrasted. Under the supervision of X-ray, PYM-GMS were perfused into the external carotid artery of rabbits by superselective artery embolization. Blood samples were tested at different time and analyzed statistically. Results: The roundness of PYM-GMS was 1.02?.005. The mean diameter was 85.6 mm, 78% of them ranging from 50-200 mm, which fitted the use of embolization. PYM content and encapsulation rate were 6.8% and 91.3% respectively. 70% of the drug was released in 3 h in the simulated environment in vivo and total drug was released after more than 6 h. After artery embolization with small dosage of PYM-GMS, the local drug concentration was 8 times higher than the blood drug concentration and the high level of local drug concentration was kept for more than 120 min. Conclusion: External carotid artery embolization with PYM-GMS, which significantly reduced the circulating drug level and employment dosage, could prolong the duration higher drug concentration and suit the purpose of targeted tumor therapy.

EXPERIMENTAL STUDY OF INTRATUMOR INJECTION WITH GELATIN MICROSPHERES CONTAINING ^(131)I AND MITOMYCIN C IN IMPLANTED HEPATOMA-22 IN MICE

The experiment of intratumor injection with gelatin microsphere containing 131I and mitomycin C (131I-MMC-GM) into implanted hepatoma-22 In mice is reported. Seventy Bal B/C mice were grouped into A, B, C, and D. Intratumor injection were given as follows: (A) 131I-MMC-GM, (B) 131I solution; (C) mitomycin C solution; (D) untreated control. The tumor-regression rates of the Group A, B and C as compared to Group D were 58. 7% , 23. 9% and 25. 4%. The average life times of Group A, B, C and were 40. 5, 25. 5, 24. 5 and 17. 1 days. Radioactivity counts in tumors and other organs in group A and B were measured with Y-Counter, which showed that 131I was concentrated in tumors in Group A but it was very low in other organs. The study showed that 131I-MMC-GM is effective and safe anticancer agent, intratumor injection with 131I-MMC-GM will be a promising therapy for the treatment of hepatoma.

Tissue Regeneration in Infected Wounds of Albino Rats Using Ciprofloxacin-Loaded Gelatin Microspheres Incorporated Collagen Scaffold: A Histological Approach with H&E Staining

A wound care system consisting of ciprofloxacin-loaded gelatin microspheres impregnated in a macroporous collagen scaffold was created to effectively control wound infection and regenerate soft tissue at the wound site.Histological and biochemical alterations were observed in infected wounds treated with these scaffolds in Albino Wistar rats.Furthermore,the study examined the immediate and prolonged release of ciprofloxacin from the scaffolds,as well as their function in eliminating bacterial infections and expediting the process of skin healing and regeneration.The developed technique was followed in the streamlined process of creating these collagen scaffolds.Compared to untreated wounds,the group receiving scaffold treatment experienced a faster rate of wound closure.It was noted that the rate of infections was considerably reduced and that full soft tissue regeneration occurred within 12 days.The development of well-deposited collagen bundles in the treated groups was demonstrated by H&E staining,which verified the flawless regeneration of the dermis and epidermis.The antimicrobial agent-loaded gelatin microspheres impregnated into the porous collagen scaffold demonstrated remarkable soft tissue regeneration and efficient infection control at the wound site.

Optimization of the Process of Gelatin-ceftiofur Sodium Microspheres

Gelatin microsphere（GMS） was prepared through W/O emulsion chemical-crossline method.The best formula was selected by examining its appearance,size,drug carrier and drug dissolution rate.The experimental results showed that the optimized gelatin microspheres were spherical ball with smooth surface and had well dispersion.The average size of blank gelatin microspheres was 15.84 μm,while the loaded microspheres＇average diameter were 33.10 μm.It was also shown that drug loading of microspheres increased with increasing loading capacity,but drug encapsulation efficiency had a trend of climbing up and then decline.The encapsulation efficiency reached the maximum when the dosage ratio was 2：1.And the results show ceftiofur sodium microspheres have sustained release in the PBS buffer of pH7.4.

Preparation of Lung Targeting Microspheres of Gelatin Ceftiofur Alkali

Gelatin ceftiofur alkali microsphere was prepared to observe its characteristics and evaluate preservation conditions. The glutaraldehyde was increased and the carboxylic methyl chitosan was added to improve the microsphere. The experimental results show microspheres have a better morphology surface and fairly regular structure with 4% glutaraldehyde. The average particle size is 15.84 gm and particle size distribution is narrow which shows a good uniformity. Microsphere size was affected by the stirrer speed, dosing ratio and curing degree. The greater drug loaded is, the better microspheres loading is; but with the increase of drug loading rate, the entrapment efficiency increases first and then decreases. The drug release rate of the microsphere is 24.90% in 0.5 h and 84.90% in 48 h, when CMC-GMs with 4% curing agent is 32.03% in 0.5 h and 88.44% in 48 h. So Gms embedding of ceftiofur alkali are better than CMC-GM. The stability tests show that strong light, high temperature, high humidity have a great influence on the microspheres.

Direct in vivo injection of ^(131)I-GMS and its distribution and excretion in rabbit

AIM: To explore the distribution and metabolism of 131 I-gelatin microspheres ( 131 I-GMSs) in rabbits after direct injection into rabbits’ livers.METHODS: Twenty-eight healthy New Zealand rabbits were divided into seven groups,with four rabbits per group.Each rabbit’s hepatic lobes were directly injected with 41.336 ± 5.106 MBq 131 I-GMSs.Each day after 131 I-GMSs administration,4 rabbits were randomly selected,and 250 μL of serum was collected for γ count.Hepatic and thyroid functions were tested on days 1,4,8,16,24,32,48 and 64 after 131 I-GMSs administration.Single-photon emission computed tomography (SPECT) was taken for each group on days 0,1,4,8,16,24,32,48,64 after 131 I-GMSs administration.A group of rabbits were sacrificed respectively on days 1,4,16,24,32,48,64 after 131 I-GMSs administration.Their livers were taken out for histological examination.RESULTS: After 131 I-GMSs administration,the nuclide was collected in the hepatic area with microspheres.The radiation could be detected on day 48 after 131 IGMSs administration,and radiography could be seen in thyroid areas in SPECT on days 4,8,16 and 24.One day after 131 I-GMSs administration,the liver function was damaged but recovered 4 d later.Eight days after 131 I-GMSs administration,the levels of free triiodothyronine and free thyroxin were reduced,which restored to normal levels on day 16.Histological examination showed that the microspheres were degraded to different degrees at 24,32 and 48 d after 131 I-GMSs administration.The surrounding parts of injection points were in fibrous sheathing.No microspheres were detected in histological examination on day 64 after 131 I-GMSs administration.CONCLUSION: Direct in vivo injection of 131 I-GMSs is safe in rabbits.It may be a promising method for treatment of malignant tumors.

Controlled-release neurotensin-loaded silk fibroin dressings improve wound healing in diabetic rat model

Diabetic foot ulcers(DFU),which may lead to lower extremity amputation,is one of the severe and chronic complications of diabetic mellitus.This study aims to develop,and use dressings based on Silk fibroin(SF)as the scaffold material,gelatin microspheres(GMs)as the carrier for the neurotensin(NT),a neuropeptide that acts as an inflammatory modulator in wound healing and NT as accelerate wound healing drug to treat DFU.We evaluated the wound healing processes and neo-tissue formation in rat diabetic model by macroscopic observation,histological observation(H&E staining and Masson's trichrome staining)and immunofluorescence analysis at 3,7,14,21 and 28 post-operation days.Our results show that the NT/GMs/SF group performance the best not only in macroscopic healing and less scars in 28 post-operation days,but also in fibroblast accumulation in tissue granulation,collagen expression and deposition at the wound site.From release profiles,we can know the GMs are a good carrier for control release drugs.The SEM results shows that the NT/GMs/SF dressings have an average pore size are 40–80μm and a porosity of∼85%,this pore size is suit for wound healing regeneration.These results suggest that the NT/GMs/SF dressings may work as an effective support for control release NT to promote DFU wound healing.